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Publisher: John Wiley and Sons   (Total: 1577 journals)

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Showing 1 - 200 of 1577 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 12, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 61, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 46, SJR: 0.547, h-index: 30)
ACEP NOW     Free   (Followers: 1)
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 49, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 143, SJR: 0.101, h-index: 9)
Acta Geologica Sinica (English Edition)     Hybrid Journal   (Followers: 3, SJR: 0.552, h-index: 41)
Acta Neurologica Scandinavica     Hybrid Journal   (Followers: 5, SJR: 1.203, h-index: 74)
Acta Obstetricia et Gynecologica Scandinavica     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 81)
Acta Ophthalmologica     Hybrid Journal   (Followers: 5, SJR: 0.112, h-index: 1)
Acta Paediatrica     Hybrid Journal   (Followers: 56, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 6, SJR: 1.69, h-index: 88)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Acta Psychiatrica Scandinavica     Hybrid Journal   (Followers: 35, SJR: 2.518, h-index: 113)
Acta Zoologica     Hybrid Journal   (Followers: 6, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 3)
Addiction     Hybrid Journal   (Followers: 33, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 12, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 24, SJR: 6.411, h-index: 86)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 50, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 13, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 251, SJR: 9.021, h-index: 345)
Advanced Materials Interfaces     Hybrid Journal   (Followers: 6, SJR: 1.177, h-index: 10)
Advanced Optical Materials     Hybrid Journal   (Followers: 5, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 5)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17, SJR: 2.729, h-index: 121)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13, SJR: 0.344, h-index: 31)
Africa Confidential     Hybrid Journal   (Followers: 19)
Africa Research Bulletin: Economic, Financial and Technical Series     Hybrid Journal   (Followers: 12)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Development Review     Hybrid Journal   (Followers: 35, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 15, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 15, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 10, SJR: 4.374, h-index: 95)
Agribusiness : an Intl. J.     Hybrid Journal   (Followers: 6, SJR: 0.627, h-index: 14)
Agricultural and Forest Entomology     Hybrid Journal   (Followers: 14, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 44, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 30, SJR: 1.122, h-index: 120)
Alcoholism and Drug Abuse Weekly     Hybrid Journal   (Followers: 7)
Alcoholism Clinical and Experimental Research     Hybrid Journal   (Followers: 7, SJR: 1.416, h-index: 125)
Alimentary Pharmacology & Therapeutics     Hybrid Journal   (Followers: 34, SJR: 2.833, h-index: 138)
Alimentary Pharmacology & Therapeutics Symposium Series     Hybrid Journal   (Followers: 3)
Allergy     Hybrid Journal   (Followers: 49, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 134, SJR: 0.951, h-index: 61)
American Business Law J.     Hybrid Journal   (Followers: 24, SJR: 0.205, h-index: 17)
American Ethnologist     Hybrid Journal   (Followers: 91, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 27, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 31, SJR: 1.761, h-index: 77)
American J. of Human Biology     Hybrid Journal   (Followers: 12, SJR: 1.018, h-index: 58)
American J. of Industrial Medicine     Hybrid Journal   (Followers: 16, SJR: 0.993, h-index: 85)
American J. of Medical Genetics Part A     Hybrid Journal   (Followers: 15, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 3, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 5, SJR: 2.315, h-index: 79)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 36, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 254, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 63)
American J. of Reproductive Immunology     Hybrid Journal   (Followers: 3, SJR: 1.347, h-index: 75)
American J. of Transplantation     Hybrid Journal   (Followers: 16, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 126, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 10, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 16)
Anatomia, Histologia, Embryologia: J. of Veterinary Medicine Series C     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 27)
Anatomical Sciences Education     Hybrid Journal   (Followers: 1, SJR: 0.633, h-index: 24)
Andrologia     Hybrid Journal   (Followers: 2, SJR: 0.528, h-index: 45)
Andrology     Hybrid Journal   (Followers: 2, SJR: 0.979, h-index: 14)
Angewandte Chemie     Hybrid Journal   (Followers: 159)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 211, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 36, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 6, SJR: 0.569, h-index: 24)
Annalen der Physik     Hybrid Journal   (Followers: 5, SJR: 1.46, h-index: 40)
Annals of Anthropological Practice     Partially Free   (Followers: 2, SJR: 0.187, h-index: 5)
Annals of Applied Biology     Hybrid Journal   (Followers: 8, SJR: 0.816, h-index: 56)
Annals of Clinical and Translational Neurology     Open Access   (Followers: 1)
Annals of Human Genetics     Hybrid Journal   (Followers: 9, SJR: 1.191, h-index: 67)
Annals of Neurology     Hybrid Journal   (Followers: 44, SJR: 5.584, h-index: 241)
Annals of Noninvasive Electrocardiology     Hybrid Journal   (Followers: 2, SJR: 0.531, h-index: 38)
Annals of Public and Cooperative Economics     Hybrid Journal   (Followers: 9, SJR: 0.336, h-index: 23)
Annals of the New York Academy of Sciences     Hybrid Journal   (Followers: 5, SJR: 2.389, h-index: 189)
Annual Bulletin of Historical Literature     Hybrid Journal   (Followers: 12)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 24, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 17, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 15)
Anthropology of Consciousness     Hybrid Journal   (Followers: 11, SJR: 0.172, h-index: 5)
Anthropology of Work Review     Hybrid Journal   (Followers: 11, SJR: 0.256, h-index: 5)
Anthropology Today     Hybrid Journal   (Followers: 93, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 45, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 6, SJR: 0.432, h-index: 59)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apmis     Hybrid Journal   (Followers: 1, SJR: 0.855, h-index: 73)
Applied Cognitive Psychology     Hybrid Journal   (Followers: 69, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 138, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 48, SJR: 0.868, h-index: 13)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5, SJR: 0.613, h-index: 24)
Aquaculture Nutrition     Hybrid Journal   (Followers: 14, SJR: 1.025, h-index: 55)
Aquaculture Research     Hybrid Journal   (Followers: 31, SJR: 0.807, h-index: 60)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 34, SJR: 1.047, h-index: 57)
Arabian Archaeology and Epigraphy     Hybrid Journal   (Followers: 11, SJR: 0.453, h-index: 11)
Archaeological Prospection     Hybrid Journal   (Followers: 12, SJR: 0.922, h-index: 21)
Archaeology in Oceania     Hybrid Journal   (Followers: 13, SJR: 0.745, h-index: 18)
Archaeometry     Hybrid Journal   (Followers: 27, SJR: 0.809, h-index: 48)
Archeological Papers of The American Anthropological Association     Hybrid Journal   (Followers: 14, SJR: 0.156, h-index: 2)
Architectural Design     Hybrid Journal   (Followers: 25, SJR: 0.261, h-index: 9)
Archiv der Pharmazie     Hybrid Journal   (Followers: 4, SJR: 0.628, h-index: 43)
Archives of Drug Information     Hybrid Journal   (Followers: 4)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (SJR: 0.768, h-index: 54)
Area     Hybrid Journal   (Followers: 12, SJR: 0.938, h-index: 57)
Art History     Hybrid Journal   (Followers: 223, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 50, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 28, SJR: 2.256, h-index: 114)
Artificial Organs     Hybrid Journal   (Followers: 1, SJR: 0.872, h-index: 60)
ASHE Higher Education Reports     Hybrid Journal   (Followers: 14)
Asia & the Pacific Policy Studies     Open Access   (Followers: 14)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 316, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 7, SJR: 0.345, h-index: 20)
Asia-pacific J. of Clinical Oncology     Hybrid Journal   (Followers: 6, SJR: 0.554, h-index: 14)
Asia-Pacific J. of Financial Studies     Hybrid Journal   (SJR: 0.241, h-index: 7)
Asia-Pacific Psychiatry     Hybrid Journal   (Followers: 3, SJR: 0.377, h-index: 7)
Asian Economic J.     Hybrid Journal   (Followers: 8, SJR: 0.234, h-index: 21)
Asian Economic Policy Review     Hybrid Journal   (Followers: 4, SJR: 0.196, h-index: 12)
Asian J. of Control     Hybrid Journal   (SJR: 0.862, h-index: 34)
Asian J. of Endoscopic Surgery     Hybrid Journal   (SJR: 0.394, h-index: 7)
Asian J. of Organic Chemistry     Hybrid Journal   (Followers: 4, SJR: 1.443, h-index: 19)
Asian J. of Social Psychology     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 37)
Asian Politics and Policy     Hybrid Journal   (Followers: 12, SJR: 0.207, h-index: 7)
Asian Social Work and Policy Review     Hybrid Journal   (Followers: 5, SJR: 0.318, h-index: 5)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5, SJR: 0.168, h-index: 15)
Assessment Update     Hybrid Journal   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 2, SJR: 0.701, h-index: 40)
Atmospheric Science Letters     Open Access   (Followers: 29, SJR: 1.332, h-index: 27)
Austral Ecology     Hybrid Journal   (Followers: 13, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 10, SJR: 0.524, h-index: 28)
Australasian J. of Dermatology     Hybrid Journal   (Followers: 8, SJR: 0.714, h-index: 40)
Australasian J. On Ageing     Hybrid Journal   (Followers: 7, SJR: 0.39, h-index: 22)
Australian & New Zealand J. of Statistics     Hybrid Journal   (Followers: 13, SJR: 0.275, h-index: 28)
Australian Accounting Review     Hybrid Journal   (Followers: 4, SJR: 0.709, h-index: 14)
Australian and New Zealand J. of Family Therapy (ANZJFT)     Hybrid Journal   (Followers: 3, SJR: 0.382, h-index: 12)
Australian and New Zealand J. of Obstetrics and Gynaecology     Hybrid Journal   (Followers: 43, SJR: 0.814, h-index: 49)
Australian and New Zealand J. of Public Health     Hybrid Journal   (Followers: 11, SJR: 0.82, h-index: 62)
Australian Dental J.     Hybrid Journal   (Followers: 7, SJR: 0.482, h-index: 46)
Australian Economic History Review     Hybrid Journal   (Followers: 4, SJR: 0.171, h-index: 12)
Australian Economic Papers     Hybrid Journal   (Followers: 25, SJR: 0.23, h-index: 9)
Australian Economic Review     Hybrid Journal   (Followers: 6, SJR: 0.357, h-index: 21)
Australian Endodontic J.     Hybrid Journal   (Followers: 3, SJR: 0.513, h-index: 24)
Australian J. of Agricultural and Resource Economics     Hybrid Journal   (Followers: 3, SJR: 0.765, h-index: 36)
Australian J. of Grape and Wine Research     Hybrid Journal   (Followers: 5, SJR: 0.879, h-index: 56)
Australian J. of Politics & History     Hybrid Journal   (Followers: 13, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 18, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 398, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 4, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 68, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 11, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 19, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 31, SJR: 2.126, h-index: 39)
Autonomic & Autacoid Pharmacology     Hybrid Journal   (SJR: 0.371, h-index: 29)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
Basic & Clinical Pharmacology & Toxicology     Hybrid Journal   (Followers: 10, SJR: 0.539, h-index: 70)
Basic and Applied Pathology     Open Access   (Followers: 2, SJR: 0.113, h-index: 4)
Basin Research     Hybrid Journal   (Followers: 5, SJR: 1.54, h-index: 60)
Bauphysik     Hybrid Journal   (Followers: 2, SJR: 0.194, h-index: 5)
Bauregelliste A, Bauregelliste B Und Liste C     Hybrid Journal  
Bautechnik     Hybrid Journal   (Followers: 1, SJR: 0.321, h-index: 11)
Behavioral Interventions     Hybrid Journal   (Followers: 9, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 23, SJR: 0.736, h-index: 57)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 9, SJR: 0.11, h-index: 5)
Beton- und Stahlbetonbau     Hybrid Journal   (Followers: 2, SJR: 0.493, h-index: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6, SJR: 0.311, h-index: 26)
Bioelectromagnetics     Hybrid Journal   (Followers: 1, SJR: 0.568, h-index: 64)
Bioengineering & Translational Medicine     Open Access  
BioEssays     Hybrid Journal   (Followers: 10, SJR: 3.104, h-index: 155)
Bioethics     Hybrid Journal   (Followers: 14, SJR: 0.686, h-index: 39)
Biofuels, Bioproducts and Biorefining     Hybrid Journal   (Followers: 1, SJR: 1.725, h-index: 56)
Biological J. of the Linnean Society     Hybrid Journal   (Followers: 15, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 3, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 42, SJR: 0.12, h-index: 1)
Biology of the Cell     Full-text available via subscription   (Followers: 9, SJR: 1.812, h-index: 69)
Biomedical Chromatography     Hybrid Journal   (Followers: 6, SJR: 0.572, h-index: 49)
Biometrical J.     Hybrid Journal   (Followers: 5, SJR: 0.784, h-index: 44)
Biometrics     Hybrid Journal   (Followers: 37, SJR: 1.906, h-index: 96)
Biopharmaceutics and Drug Disposition     Hybrid Journal   (Followers: 10, SJR: 0.715, h-index: 44)
Biopolymers     Hybrid Journal   (Followers: 18, SJR: 1.199, h-index: 104)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 45, SJR: 0.415, h-index: 55)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 136, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 13, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 18, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 9, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 35, SJR: 0.763, h-index: 64)
Birth Defects Research Part A : Clinical and Molecular Teratology     Hybrid Journal   (Followers: 2, SJR: 0.727, h-index: 77)
Birth Defects Research Part B: Developmental and Reproductive Toxicology     Hybrid Journal   (Followers: 5, SJR: 0.468, h-index: 47)
Birth Defects Research Part C : Embryo Today : Reviews     Hybrid Journal   (SJR: 1.513, h-index: 55)
BJOG : An Intl. J. of Obstetrics and Gynaecology     Partially Free   (Followers: 221, SJR: 2.083, h-index: 125)

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Journal Cover Advanced Optical Materials
  [SJR: 2.488]   [H-I: 21]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Online) 2195-1071
   Published by John Wiley and Sons Homepage  [1577 journals]
  • Masthead: (Advanced Optical Materials 9/2017)
    • PubDate: 2017-05-03T07:27:58.409059-05:
      DOI: 10.1002/adom.201770050
       
  • Biocompatible Organic Electronics: Dibenzoindigo: A Nature-Inspired
           Biocompatible Semiconductor Material for Sustainable Organic Electronics
           (Advanced Optical Materials 9/2017)
    • Authors: Lidiya I. Leshanskaya; Irina V. Klimovich, Dolgor D. Dashitsyrenova, Lyubov A. Frolova, Elizaveta S. Ershova, Vasilina A. Sergeeva, Vyacheslav Yu. Tabakov, Svetlana V. Kostyuk, Konstantin A. Lyssenko, Pavel A. Troshin
      Abstract: Blue colorant indigo, occurring in Indigofera tinctoria plant, attracts much attention as ambipolar semiconductor designed by nature. In article number 1601033, Pavel A. Troshin and co-workers present a nature-inspired material dibenzoindigo, which shows remarkably improved electrical performance compared to parent indigo and also excellent ambient and photostability. Biological assays reveal that dibenzoindigo positively influences proliferation of human cells, which paves a way towards an extensive application of this material in biocompatible electronics.
      PubDate: 2017-05-03T07:27:56.838786-05:
      DOI: 10.1002/adom.201770047
       
  • Optical Modulation: Few-Layer Phosphorene-Decorated Microfiber for
           All-Optical Thresholding and Optical Modulation (Advanced Optical
           Materials 9/2017)
    • Authors: Jilin Zheng; Xian Tang, Zhenghua Yang, Zhiming Liang, Yunxiang Chen, Ke Wang, Yufeng Song, Ying Zhang, Jianhua Ji, Yong Liu, Dianyuan Fan, Han Zhang
      Abstract: In article number 1700026, Han Zhang and co-workers fabricate and investigate few-layer phosphorene (FL-P) microfibers. All-optical thresholding and optical modulation are demonstrated for optical communications by using these microfibers, which can dramatically suppress noise level and switch the signal on/off by pumping light. The cover picture shows an all-optical thresholder (top) and all-optical modulator (bottom) based on FL-P-coated microfibers and their effects on optical signals.
      PubDate: 2017-05-03T07:27:55.398759-05:
      DOI: 10.1002/adom.201770048
       
  • Contents: (Advanced Optical Materials 9/2017)
    • PubDate: 2017-05-03T07:27:55.30587-05:0
      DOI: 10.1002/adom.201770049
       
  • Highly Efficient Organic Light-Emitting Diode Using A Low Refractive Index
           Electron Transport Layer
    • Authors: Amin Salehi; Szuheng Ho, Ying Chen, Cheng Peng, Hartmut Yersin, Franky So
      Abstract: A low refractive index electron transport layer (ETL) can be very effective in enhancing the out-coupling efficiency of an organic light-emitting diode (OLED). However, most organic films show a refractive index close to 1.8. In this work, it has been discovered that tris-[3-(3-pyridyl)mesityl]borane (3TPYMB) has a low refractive index of 1.65 (at 550 nm), which is the lowest refractive index ETL among the commonly used ETLs up to date. Using 3TPYMB as an ETL, a solution processed OLED is demonstrated with nearly a 76% enhancement in external quantum efficiency (EQE). Optical simulation results of this study show that 59% of the enhancement comes from the low refractive index 3TPYMB, and the remaining 17% from the change in charge balance due to the 3TPYMB ETL in the OLED devices.Tris-[3-(3-pyridyl)mesityl]borane (3TPYMB) is found to have the lowest refractive index among common electron transport materials. A 76% enhancement of efficiency is observed when using 3TPYMB as the electron transport layer (ETL) in an organic light-emitting diode (OLED). The effect of low refractive index ETL on suppression of loss to surface plasmon polaritons and enhancing light extraction in OLEDs is disscussed.
      PubDate: 2017-05-02T10:32:25.683693-05:
      DOI: 10.1002/adom.201700197
       
  • Optically Switchable Luminescent Hydrogel by Synergistically Intercalating
           Photochromic Molecular Rotor into Inorganic Clay
    • Authors: Guoxing Liu; Ying-Ming Zhang, Xiufang Xu, Lu Zhang, Yu Liu
      Abstract: Photomodulated luminescent hydrogels are of great potential for construction of functional soft materials. Herein a simple yet effective approach, by synergistically intercalating the dithienylethene-bridged bispyridinium dye into the inorganic clay of Laponite, is proposed to immobilize the dye's molecular conformation and then to activate the hydrogel's fluorescence emission. The incorporation with dithienylethene unit can not only increase the π-conjugation of organic dye but also endow the obtained supramolecular hydrogel with desirable photoswitchable capability. It can be envisioned that this organic–inorganic hybrid hydrogel featuring reversible luminescence switching behavior, high water content, good transparency, and mouldability may offer a practical strategy to create more advanced intelligent materials.Dithienylethene-bridged bispyridinium dye as a photochromic molecular rotor is synergistically intercalated into the inorganic clay of Laponite by multiple electrostatic interactions, thus exhibiting photoswitchable luminescence behaviors via the restriction of intramolecular rotation in the hydrogel state. This “rotor–gel conjugation” construction method may offer a brand new strategy for designing and developing water-based soft materials.
      PubDate: 2017-05-02T10:32:21.459021-05:
      DOI: 10.1002/adom.201700149
       
  • Tunable Transfer of Molecules between Liquid Crystal Microdroplets and
           Control of Photonic Crystallinity in Isolated Microdroplets
    • Authors: Jin-Kun Guo; Jagdish K. Vij, Jang-Kun Song
      Abstract: Selective molecular transfer among living cells or organs is involved in all vital processes; however, the artificial molecule transfer technology, an innovative tool in optical devices and materials science, is still at an early stage of development. Here, this paper demonstrates the controlled in situ molecular transfer between the heterogeneous liquid crystal (LC) microdroplets in an LC emulsion. Chiral dopants can be transferred between nematic and cholesteric LC droplets, which are the receiver and supplier of chiral molecules, respectively, and a continuous phase with tunable solubility acts as the switchable transfer channel. The molecular transfer is visually monitored by the topological transition and the change in the photonic crystalline reflection colors of the LC droplets. These enable to continuously record and manipulate the topological evolution and structural color. This technology may be applicable to other systems in optical applications, materials science, and biology.In situ controllable molecular transfer between heterogeneous liquid crystal (LC) microdroplets is demonstrated in an LC emulsion. Chiral dopants can be transferred between nematic and cholesteric LC droplets, and the molecular transfer is visually monitored by the topological transition and the change in the photonic crystalline reflection colors of the LC droplets.
      PubDate: 2017-05-02T10:32:16.067881-05:
      DOI: 10.1002/adom.201700119
       
  • Using Intrinsic Intracrystalline Tunnels for Near-Infrared and
           Visible-Light Selective Electrochromic Modulation
    • Authors: Zhen Wang; Qingzhu Zhang, Shan Cong, Zhigang Chen, Jinxiong Zhao, Mei Yang, Zuhui Zheng, Sha Zeng, Xuwen Yang, Fengxia Geng, Zhigang Zhao
      Abstract: Dual-band electrochromic composite materials are of utmost importance in advancing the electrochromic field toward achieving the ideal smart window with independent control over visible and near-infrared (NIR) radiation. However, such composites usually need deliberate architecting of their mesoscale structure (e.g., via block copolymer-templating method) to make the electrolyte contact with both NIR and visible-light modulating components. Herein, instead of arduously making exterior pores, the intrinsic structural tunnels are utilized directly in electrochromic materials to facilitate the accommodation and transportation of insertion ions, which permit the infiltration of the electrolyte to be in contact with both visible (Prussian blue) and NIR-light modulating components (nonstoichiometric tungsten oxide). Such simple-fabricated composite materials exhibit excellent dual-band electrochromic performance with an unprecedented dynamic optical range for modulation of visible and NIR light, up to 71.2% at 633 nm and 64.8% at 1600 nm, respectively.Intrinsic intracrystalline tunnels in electrochromic materials are utilized to facilitate the accommodation and transportation of insertion ions. Such simply fabricated composite materials exhibit excellent dual-band electrochromic performance with an unprecedented dynamic optical range for modulation of visible and near-infrared (NIR) light, up to 71.2% at 633 nm and 64.8% at 1600 nm, respectively.
      PubDate: 2017-04-27T19:07:08.199684-05:
      DOI: 10.1002/adom.201700194
       
  • Chiral Nanostructured CuO Films with Multiple Optical Activities
    • Authors: Yiwen Qian; Yingying Duan, Shunai Che
      Abstract: Chiral semiconductor nanomaterials with optical activity have intrigued magnificent attention due to their potential technological applications, but so far there have been no reports of chiral optically active CuO nanofilms. In this work, a facile chemical method to deposit chiral CuO nanoflowers on an activated quartz substrate is demonstrated. Three levels of chirality in CuO nanofilms are demostrated by structural analysis: tertiary helically arranged “nanopetals” assembled from secondary helically stacking “nanoplates.” Primary twisting chiral nanostructure of the nanoplate is believed to exist after careful examination on circular dichroism optical responses given by the CuO nanofilms. Originated from hierarchical chiralites, the CuO films exhibit both the electron transition absorption-based optical activity at the characteristic absorption bands and reflection-based optical activity arising from the long-range periodic structure at the circular Bragg resonance.Optically active chiral CuO nanofilms are fabricated on an activated quartz substrate through a versatile hydrothermal synthesis method. Tertiary helically arranged “nanopetals” are assembled from secondary helically stacking “nanoplates”. The primary twisting chiral nanostructure of the nanoplates is revealed by their optical responses. Originating from hierarchical chirality, the CuO nanofilms exhibit both electron transition absorption-based and reflection-based optical activities.
      PubDate: 2017-04-27T19:03:22.606736-05:
      DOI: 10.1002/adom.201601013
       
  • Time-Resolved Pump–Probe Measurement of Optical Rotatory Dispersion
           in Chiral Metamaterial
    • Authors: Jae Heun Woo; Boyoung Kang, Minji Gwon, Ji Hye Lee, Dong-Wook Kim, William Jo, Dong Ho Kim, Jeong Weon Wu
      Abstract: A plasmonic chiral metamaterial is fabricated from a thin Au film and exhibits static optical rotatory power (ORP) in the visible spectral range. Transient ORP is measured to clarify the temporal development of ORP using a circularly polarized light (CPL) pump beam. Three distinct transient behaviors of ORP are identified, resulting from different energy relaxation processes of hot electrons that occur during a period of a few picoseconds after pumping. Nonthermal hot electrons experience Lorentz force from an inverse Faraday effect and electron–boundary scattering, yielding a pump beam CPL helicity-dependent transient ORP. Once hot electrons are in thermal equilibrium with the lattice, electron energy is distributed among the occupied states, as described by Fermi–Dirac statistics. Moreover, the transient ORP is independent of pump beam CPL helicity, well explained by the selection rule of electron excitation and two-temperature model of the electron cooling process. Theoretical analysis of the transient ORP in terms of the energy relaxation of thermal hot electrons is carried out by introducing a temperature-dependent dielectric function and finite-difference time-domain simulation. It is found that the magnitude of ORP at an elevated temperature is reduced to less than that at room temperature, agreeing well with the experimental observation.Time-resolved pump–probe experiment is performed to measure ultrafast optical rotatory dispersion in a chiral metamaterial. Using a circularly polarized light pump beam, it is clarified that sub-picosecond hot electron dynamics carries information regarding the handedness of chiral metallic inclusion of chiral metamaterial. Once thermalized, the transient optical rotatory dispersion is found to be independent of pump beam circularly polarized light helicity.
      PubDate: 2017-04-27T18:56:11.176594-05:
      DOI: 10.1002/adom.201700141
       
  • Dispersion Topological Darkness at Multiple Wavelengths and Polarization
           States
    • Authors: Haomin Song; Nan Zhang, Jiyuan Duan, Zhejun Liu, Jun Gao, Matthew H. Singer, Dengxin Ji, Alec R. Cheney, Xie Zeng, Borui Chen, Suhua Jiang, Qiaoqiang Gan
      Abstract: Complete suppression of reflection is in principle achievable in ideal optical systems with unique optical features including complete light absorption, abrupt phase change, etc. However, conventional optical systems have an extremely tight tolerance on fabrication errors or inherent roughness of thin films or patterns. Therefore, it is difficult to realize the perfect reflectionless condition in practice. To overcome this challenge, a “topological darkness” concept with mild restrictions to the film quality is proposed using periodic metallic patterns and self-assembled core–shell particles. Due to the topological effect, the robust nature of reflectionless surfaces is improved dramatically even in the presence of imperfections. Here the “mild” restriction will be further broken to realize reflectionless thin film systems using directly deposited thin films or random metal nanoparticles. Moreover, a broad absorption band is achieved by tuning the effective optical constants of the top absorbing layer. Remarkably, compared with conventional reflectionless phenomena under single polarization states and wavelengths, the system can realize multiwavelength zero-reflection points for both polarization states on the same chip. These proof-of-concept results pave the way toward the development of practical applications using abrupt phase change and complete light absorption for label-free optical sensing and enhanced light-matter interaction within ultrathin film systems.Reflectionless thin film systems, with a large tolerance on fabrication errors and surface roughness, are realized using directly deposited thin films or random metal nanoparticles. Moreover, a broad absorption band is achieved by tuning the effective optical constants of the top absorbing layer. Remarkably, the system can realize multiwavelength zero-reflection points for both polarization states on the same chip.
      PubDate: 2017-04-27T18:37:21.843291-05:
      DOI: 10.1002/adom.201700166
       
  • Hot-Electron-Mediated Photochemical Reactions: Principles, Recent
           Advances, and Challenges
    • Authors: Minho Kim; Mouhong Lin, Jiwoong Son, Hongxing Xu, Jwa-Min Nam
      Abstract: Hot electron chemistry has drawn tremendous attention from applications related to materials, energy, sensing, and catalysis. The plasmon-induced generation of hot electrons and their transfer behavior are very important for understanding plasmonic-enhanced applications and for achieving practically useful efficiency. From a plasmonic perspective, well-designed plasmonic structures that can manipulate surface plasmons are able to enhance the efficiencies of hot electron-based processes. This progress report summarizes the recent experimental and theoretical advances on the hot electron effect, emphasizing the crucial role of surface plasmons that are highly designable by using metal nanostructures. In particular, recent breakthroughs in the emerging fields of heterogeneous catalysis based on the hot electron effect are highlighted. Important design principles, mechanisms, and concepts, as well as challenges and perspectives, are illustrated and discussed.Hot electron-mediated photochemical reactions that transform light into useful chemical energy are of particular interest. This progress report covers the up-to-date knowledge in theory and mechanism of plasmonic hot-electron dynamics and the structural design of high-efficiency photocatalyst. Recent advances and perspectives in hot-electron-induced chemical reactions are also introduced and discussed.
      PubDate: 2017-04-24T06:11:48.563215-05:
      DOI: 10.1002/adom.201700004
       
  • Pancharatnam–Berry Phase Manipulating Metasurface for Visible Color
           Hologram Based on Low Loss Silver Thin Film
    • Authors: Sajid Choudhury; Urcan Guler, Amr Shaltout, Vladimir M. Shalaev, Alexander V. Kildishev, Alexandra Boltasseva
      Abstract: This study demonstrates visible color hologram using a plasmonic metasurface. The metasurface is fabricated by perforating nanoslits in a 50 nm thick monocrystalline silver film that is ultrasmooth and has ultralow loss compared to conventional polycrystalline silver films commonly used in plasmonics. The designed plasmonic hologram is the thinnest metasurface hologram operating in transmission mode to the best of our knowledge. Holograms of three individual component colors (red, green, and blue) are demonstrated in transmission mode, and a scheme for generating polychromatic hologram is illustrated. By adjusting the slit dimensions and orientation, the phase of a visible spectrum light can be controlled, paving the way to applications of ultracompact polychromatic plasmonic metasurfaces for advanced light manipulation.A hologram of red, green, and blue colors is generated in a virtual imaging plane using a plasmonic metasurface based on epitaxial silver. To the best of the authors' knowledge, the presented hologram is the thinnest metasurface hologram operating in transmission mode.
      PubDate: 2017-04-24T06:11:08.335672-05:
      DOI: 10.1002/adom.201700196
       
  • UV-Blocking Photoluminescent Silicon Nanocrystal/Polydimethylsiloxane
           Composites
    • Authors: Dongzhi Chen; Wei Sun, Chenxi Qian, Annabelle P. Y. Wong, Laura M. Reyes, Geoffrey A. Ozin
      Abstract: It is a challenge to synthesize transparent polydimethylsiloxane (PDMS) materials that can completely absorb the light energy of ultraviolet (UV) A, B, and C regions. Herein, near-infrared (NIR) photoluminescent PDMS composites with hydrogen-terminated silicon nanocrystals (ncSi:H) or decyl-terminated silicon nanocrystals (ncSi-decyl) fabricated by combination of hydrosilylation and polymer encapsulation are reported. Their morphologies, optical and mechanical properties, and thermal stabilities are investigated. It is interesting to find that these PDMS composites filled with even a very small amount of ncSi:H or ncSi-decyl have unprecedented UV-blocking properties and superior thermal stabilities as compared to the PDMS reference. In particular, the ncSi-decyl/PDMS composite possesses impressive photoluminescence. Furthermore, ncSi-decyl are favorable for reinforcing the mechanical properties of the PDMS composites as compared to the PDMS reference and the ncSi:H/PDMS composite. The enhancement in the mechanical properties and thermal stabilities of these novel PL PDMS composites depends upon the creation of crosslinkable sites and entanglement interactions between the PDMS chains and the ncSi. These results suggest that potential applications for NIR photoluminescent ncSi/PDMS composites will likely be found in the fields of advanced UV-blocking textiles, cosmetics, photofluids, stretchable electronic devices, anticounterfeiting materials, biological imaging, and diagnostics.A new class of nanocrystal-polymer composites with unprecedented UV-blocking properties and impressive photoluminescent, mechanical, and stability attributes that originate from very low loading of silicon nanocrystals in polydimethylsiloxane, is fabricated. Applications for these composites will likely be found in the fields of advanced UV-blocking textiles, cosmetics, photofluids, stretchable electronic devices, anticounterfeiting materials, biological imaging, and diagnostics.
      PubDate: 2017-04-24T02:06:23.335954-05:
      DOI: 10.1002/adom.201700237
       
  • Broadband and Robust Metalens with Nonlinear Phase Profiles for Efficient
           Terahertz Wave Control
    • Authors: Quanlong Yang; Jianqiang Gu, Yuehong Xu, Xueqian Zhang, Yanfeng Li, Chunmei Ouyang, Zhen Tian, Jiaguang Han, Weili Zhang
      Abstract: Metasurfaces, 2D artificial electromagnetic media, open up a new frontier of functional device design ranging from radio waves to the visible region. Particularly, metasurface-based lenses are indispensable in various practical terahertz applications. The authors aim at achieving flexible and robust metalenses for efficient terahertz wave control. In general, resolution and efficiency are two inevitable parameters in determining the focusing and imaging abilities of lenses, which however are rarely experimentally demonstrated in the terahertz band. In this Communication, three broadband and robust metalenses with nonlinear phase profiles are proposed, all of which are experimentally investigated by using near-field scanning terahertz microscopy (NSTM) with a spatial resolution of 50 µm. The measurement shows that the metalens can focus a 0.95 THz wave to a spot size of 580 µm and achieve a transmittance efficiency of 45%. In addition, the NSTM system facilitates an experimental investigation of the incidence angle dependence of the terahertz metalens, which proves the robust focusing feature of the proposed device. This demonstration delivers a promising metasurface design for potential applications in imaging and information processing that may be of interest for the entire electromagnetic spectrum.A broadband and robust terahertz metalens with nonlinear phase profile is proposed. The metalens delivers a transmittance efficiency as high as 45%. A near-field scanning terahertz microscopy system facilitates characterization of a 580 µm focusing spot with a high spatial resolution of 50 µm, and the experimental investigation of the robustness of the metalens under tilted incidence.
      PubDate: 2017-04-20T07:38:14.115757-05:
      DOI: 10.1002/adom.201601084
       
  • Pure Blue and Highly Luminescent Quantum-Dot Light-Emitting Diodes with
           Enhanced Electron Injection and Exciton Confinement via Partially Oxidized
           Aluminum Cathode
    • Authors: Tai Cheng; Zhibin Wang, Shengli Jin, Fuzhi Wang, Yiming Bai, Haoxian Feng, Baogui You, Yang Li, Tasawar Hayat, Zhan'ao Tan
      Abstract: The balance injection of holes and electrons into a thin emissive quantum dot (QD) layer for efficient radiative recombination is critical to the color purity, stability, and efficiency of the QD-based light-emitting diodes (QD-LEDs). Due to the difficulty of charge injection into wide band gap blue QD layer, the performance of blue QD-LED is obviously inferior to the green and red counterparts. Here, high-performance ZnCdS/ZnS graded core/shell-based blue QD-LEDs with partial oxidized aluminum cathode (Al:Al2O3) via simple autoxidation are demonstrated. There is no any additional electron transport layer/hole transport layer involved in the device, which guarantees the color purity and simplifies the fabrication processes. Furthermore, the Al:Al2O3 cathode greatly enhances the charge injection and exciton recombination, rendering significant improvement in luminance and current efficiency compared with the control devices with Al or Alq3/Al electrodes. A record luminance of over 13 000 cd m−2 has been achieved for blue QD-LEDs with Al:Al2O3 cathode. The findings of this study indicate that this simply processed and easily controlled autoxidation procedure is a promising strategy to achieve high-performance blue QD-LEDs.A partially oxidized aluminum cathode (Al:Al2O3) is applied in ZnCdS/ZnS quantum-dot-based blue light-emitting diodes. Without any electron transport layer/hole transport layer involved, the Al:Al2O3 cathode via simple autoxidation greatly enhances the electron injection and exciton radiative recombination, rendering a significant improvement in luminance (13 000 cd m−2) and current efficiency (1.1 cd A−1), while pure deep blue light emission is guaranteed.
      PubDate: 2017-04-20T07:38:08.359884-05:
      DOI: 10.1002/adom.201700035
       
  • Aluminum Nanoparticles with Hot Spots for Plasmon-Induced Circular
           Dichroism of Chiral Molecules in the UV Spectral Interval
    • Authors: Lucas V. Besteiro; Hui Zhang, Jérôme Plain, Gil Markovich, Zhiming Wang, Alexander O. Govorov
      Abstract: Plasmonic nanocrystals with hot spots are able to localize optical energy in small spaces. In such physical systems, near-field interactions between molecules and plasmons can become especially strong. This paper considers the case of a nanoparticle dimer and a chiral biomolecule. In this model, a chiral molecule is placed in the gap between two plasmonic nanoparticles, where the electromagnetic hot spot occurs. Since many important biomolecules have optical transitions in the UV spectral region, the case of aluminum nanoparticles is considered, as they offer strong electromagnetic enhancements in the blue and UV spectral intervals. The calculations in this study show that the complex composed of a chiral molecule and an Al dimer exhibits strong circular dichroism (CD) signals in the plasmonic spectral region. In contrast to the standard Au and Ag nanocrystals, the Al system may have a much better spectral overlap between the typical biomolecule's optical transitions and the nanocrystals' plasmonic band. Overall, it is found that Al nanocrystals used as CD antennas exhibit unique properties as compared to other commonly studied plasmonic and dielectric materials. The plasmonic systems investigated in this study can be potentially used for sensing chirality of biomolecules, which is of interest in applications such as drug development.The chiral optical signal of biomolecules can be shifted and enhanced using plasmonic nanoparticles, facilitating the identification of their structure. Plasmon resonances in Al nanoparticles provide large field enhancements in the UV spectral interval, near the typical excitation spectra of biomolecules. This theoretical study of molecule–nanoparticle complexes compares Al with other plasmonic materials for their application in chiral dichroism spectroscopy.
      PubDate: 2017-04-20T07:38:03.442397-05:
      DOI: 10.1002/adom.201700069
       
  • Moiré Chiral Metamaterials
    • Authors: Zilong Wu; Yuebing Zheng
      Abstract: Plasmonic chiral metamaterials are promising for applications in chiral sensors and photonic devices due to their strong optical chirality and light–matter interactions at the subwavelength scale. However, most of current plasmonic chiral metamaterials rely on local structural chirality or site-specific symmetry breaking, which has limited their optical activity, tunability, and scalable fabrication for practical applications. Here, this paper reports a new type of chiral metamaterials consisted of two layers of identical achiral Au nanohole arrays stacked into moiré patterns. The chiroptical responses of the moiré chiral metamaterials can be precisely tuned by the in-plane rotation between the two layers of nanohole arrays. Furthermore, the moiré chiral metamaterials are applied to achieve label-free enantiodiscrimination of biomolecules and drug molecules at the picogram level. With their ultrathin thickness (≈70 nm, which is only ≈1/10 of the operation wavelength), strong chirality, and high tunability, the moiré chiral metamaterials will advance a variety of photonic and optoelectronic applications.A new type of chiral metamaterials, known as moiré chiral metamaterials (MCMs), is developed. The optical chirality can be precisely tuned by the relative rotation between the lattice directions of the two Au nanohole arrays. It is demonstrated that MCMs can distinguish a chiral drug, R-thalidomide, from its medically toxic enantiomer at picogram level in a label-free manner.
      PubDate: 2017-04-20T07:37:45.466013-05:
      DOI: 10.1002/adom.201700034
       
  • Microscopic Interference Full-Color Printing Using Grayscale-Patterned
           Fabry–Perot Resonance Cavities
    • Authors: Zhengmei Yang; Yiqin Chen, Yanming Zhou, Yasi Wang, Peng Dai, Xupeng Zhu, Huigao Duan
      Abstract: This study demonstrates a full-color printing concept based on the interference effect in pixelized metal–dielectric–metal Fabry–Perot (FP) resonance cavities. The pixel color for printing is determined by the thickness of the dielectric layer in each microscale FP cavity. Abundant colors with controllable brightness and saturation are achieved by varying both the thickness and the filling density of the FP cavities using grayscale lithography. Enabled by the wide color gamut, a vivid full-color image can be reproduced at the microscopic scale with high resolution by correlating the colors with the dimensional parameters of the FP cavities through a layout-generation algorithm. The colorization strategy based on interference effects provides a new opportunity to use artificial structures for color printing and also has the potential to be scaled up for large-volume application in consumable products using replica patterning techniques such as grayscale photolithography, nanoimprinting, and soft lithography.In this study, in combination with appropriate structural design, unique grayscale patterning process using transparent inorganic resist as the dielectric layer and a sort of fabrication-layout-generation algorithm, high-resolution vivid microscopic color images are able to be printed.
      PubDate: 2017-04-18T04:51:44.106983-05:
      DOI: 10.1002/adom.201700029
       
  • Solution-Phase Synthesis of Cesium Lead Halide Perovskite Microrods for
           High-Quality Microlasers and Photodetectors
    • Authors: Shuai Wang; Kaiyang Wang, Zhiyuan Gu, Yujie Wang, Can Huang, Ningbo Yi, Shumin Xiao, Qinghai Song
      Abstract: Recently, due to broad wavelength tunability and high material stability, cesium lead halide perovskite nanorods have been intensively studied as potential candidates for microlasers and photodetectors. However, the current CsPbX3 perovskite nanorods can only support low quality (Q) Fabry–Perot lasers and the response time of CsPbX3 nanorod photodetector is extremely long. Here, CsPbBr3 microrods with larger cross-sectional sizes and almost uniform aspect ratio are successfully synthesized with a solution processed one-step precipitation method and their applications in microlasers and photodetectors are reported. Due to the larger cross-sectional size, whispering-gallery-mode lasers can be formed in the transverse plane of CsPbBr3 microrod under both of one-photon and two-photon excitation. The highest Q factor can reach around 7000. Besides, the synthesized CsPbBr3 perovskite lasers have shown much better photostability and thermal stability. The single-crystalline CsPbBr3 microrods also provide a stable platform for photodetectors. The rise and decay time of CsPbBr3 microrod based photodetectors are around 8 ms, which are almost two orders of magnitude smaller than the previously reported CsPbX3 microrod photodetector. Such findings can pave new route on all-inorganic CsPbX3 based optoelectronic devices.Single-crystal CsPbBr3 microrods with larger cross-sectional sizes and uniform aspect ratio are synthesized with a one-step solution precipitation method. Due to the high crystal quality, the CsPbBr3-microrod-based microlasers and photodetectors exhibit an ultrahigh quality factor (7000) and a fast response time (8 ms), respectively. Such findings can pave new routes to microsized coherent light sources, detecting, and imaging, etc.
      PubDate: 2017-04-13T09:53:00.418864-05:
      DOI: 10.1002/adom.201700023
       
  • Filled Skutterudites for Broadband Saturable Absorbers
    • Authors: Junsu Lee; Byung-Kyu Yu, Young In Jhon, Joonhoi Koo, Sung Jin Kim, Young Min Jhon, Ju Han Lee
      Abstract: Filled skutterudites (FSs), which are known to be good thermoelectric materials, have been intensively investigated in the field of condensed matter physics in the past decades, due to their large variety of electronic and magnetic properties. However, to the best of the authors' knowledge, there has been no previous investigation of the optical properties of FSs. The nonlinear optical saturable absorption property of FSs is investigated in this work for the first time, and the results are reported here. More specifically, Co4Sb12 is chosen as a binary skutterudite system, and indium ions are added as a filling element to form a FS of In0.2Co4Sb12. The material properties are systematically investigated using a series of measurements. Density functional theory calculations of the electronic band structures of InCo4Sb12 and In0.25Co4Sb12 are conducted for better understanding of their energy band structures. It is also demonstrated that a broadband saturable absorber (SA) that can simultaneously operate at 1.5 and 1.9 µm can readily be implemented by depositing particles of In0.2Co4Sb12 onto fiber ferrules. The efficacy of the prepared SA is tested by incorporating the device into rare earth ion-doped fiber ring cavities, to show its capability for both 1.5 and 1.9 µm operation.This is the first time demonstration of the nonlinear optical properties of filled skutterudites (FSs), which are known to be good thermoelectric materials. The nonlinear saturable absorption in an FS of In0.2Co4Sb12 is investigated theoretically and experimentally. An FS-based saturable absorber that can simultaneously operate at 1.5 and 1.9 μm, is fabricated and tested within rare earth ion-doped fiber ring cavities.
      PubDate: 2017-04-13T09:52:18.716093-05:
      DOI: 10.1002/adom.201700096
       
  • Periodically Aligned Dye Molecules Integrated in a Single MOF Microcrystal
           Exhibit Single-Mode Linearly Polarized Lasing
    • Authors: Huajun He; En Ma, Jiancan Yu, Yuanjing Cui, Yuankun Lin, Yu Yang, Xueyuan Chen, Banglin Chen, Guodong Qian
      Abstract: Due to the periodically physical/chemical environment and high-efficient confinement effect of the metal-organic framework (MOF) only possessing 1D channels, the authors realize periodically and highly aligned dye molecule integration within the MOF hybrid material ZJU-68⊃DMASM. Such molecule integration can provide an opportunity to directly determine 4-[p-(dimethylamino)styryl]-1-methylpyridinium (DMASM) molecules in the MOF channels by electron density mapping using X-ray diffraction data. Furthermore, combining the anisotropic emission property of such molecule integration and the perfect crystal morphology of ZJU-68 serving as the natural resonant cavity, the authors obtain a single-mode linearly polarized laser excited by light ranging from visible to near-infrared.A periodically aligned laser dye molecules integrated within the metal-organic framework (MOF) ZJU-68 exhibit σ-polarized single-mode lasing. Such molecule integration provides an opportunity to directly determine dye molecules in the MOF channels by electron density mapping via X-ray diffraction data and exhibits significant anisotropic properties of light absorption and emission.
      PubDate: 2017-04-12T07:42:23.96712-05:0
      DOI: 10.1002/adom.201601040
       
  • Few-Layer Phosphorene-Decorated Microfiber for All-Optical Thresholding
           and Optical Modulation
    • Authors: Jilin Zheng; Xian Tang, Zhenghua Yang, Zhiming Liang, Yunxiang Chen, Ke Wang, Yufeng Song, Ying Zhang, Jianhua Ji, Yong Liu, Dianyuan Fan, Han Zhang
      Abstract: Phosphorene, mono/few-layered black phosphorous with advantages of tunable energy bandgaps and strong light–matter interaction, is fabricated by electrochemical intercalation with large area (≈3 µm) and controllable thickness (mainly four layers). Thanks to the direct gap and resonant absorption of four-layer phosphorene at the telecommunication band, all-optical thresholding and optical modulation are demonstrated for optical communications by using few-layer phosphorene-decorated microfibers. This device is experimentally verified as an efficient noise suppressor that can enhance the signal-to-noise ratio and reshape the deteriorated signal pulse, and also as an optical modulator that can switch the signal on/off by pumping light. The findings, as the first prototypic device of all-optical thresholding and optical modulation, might facilitate the development of phosphorene-based optical communication technologies.Few-layer phosphorene (FL-P) is fabricated by electrochemical intercalation with large area and controllable thickness. All-optical thresholding and optical modulation are demonstrated for optical communications by using FL-P-decorated microfibers, which can dramatically suppress noise level and switch the signal on/off by pumping light. The first prototypic devices with these two functions might facilitate the development of phosphorene-based optical communication technologies.
      PubDate: 2017-04-11T01:50:53.483463-05:
      DOI: 10.1002/adom.201700026
       
  • Multiwavelength Metasurfaces Based on Single-Layer Dual-Wavelength
           Meta-Atoms: Toward Complete Phase and Amplitude Modulations at Two
           Wavelengths
    • Authors: Jun Ding; Sensong An, Bowen Zheng, Hualiang Zhang
      Abstract: Since its invention, metasurface has been widely utilized to achieve nearly arbitrary wavefront control based on phase only modulation at single wavelength. To achieve better performance or exotic functions, it is desirable to demonstrate metasurfaces capable of realizing both phase and amplitude modulations. Meanwhile, the wavelength-dependent behavior of the metasurface is one of the critical limitations in existing metasurface structures. Specifically, single-layer metasurfaces with the capability to tailor both phase and amplitude at multiple wavelengths have not been reported so far. In this paper, a single-layer meta-atom is proposed which can realize ultrathin metasurfaces with complete phase and amplitude modulations at two THz wavelengths. Several dual-wavelength metalenses and a nondiffractive Airy beam generator operating at two THz wavelengths are numerically demonstrated, the simulated results of which are consistent with the theoretical calculations and design goals. The presented dual-wavelength meta-atom can provide a powerful building block in multiwavelength metasurface designs for controlling electromagnetic waves, including focusing, beam steering, beam generations, hologram, etc.A single-layer dual-wavelength metasurface meta-atom is proposed to tailor both phase and amplitude responses simultaneously at two terahertz wavelengths, which is verified by several dual-wavelength metadevices. The presented dual-wavelength meta-atom can provide a powerful building block in multiwavelength metasurface designs for controlling electromagnetic waves, including focusing, beam steering, beam generations, hologram, etc.
      PubDate: 2017-04-07T07:37:29.993802-05:
      DOI: 10.1002/adom.201700079
       
  • Plasmonic Thermal Emitters for Dynamically Tunable Infrared Radiation
    • Authors: Amir Kazemi Moridani; Robert Zando, Wanting Xie, Irene Howell, James J. Watkins, Jae-Hwang Lee
      Abstract: Periodic bimetallic microstructures using nickel and gold are fabricated on an elastomeric substrate by use of strain-induced buckling of the metallic layers, which can be compatible with roll-to-roll manufacturing. The intrinsically low emissivity of gold in the midinfrared regime is selectively enhanced by the surface plasmonic resonance at three different midinfrared wavelengths, 4.5, 6.3, and 9.4 µm, respectively, which directly correspond to the structural periodicities of the metallic microstructures. As the thermal emission enhancement effect exists only for the polarization perpendicular to the orientation of the microstructures, substantially polarized thermal emission with an extinction ratio close to 3 is demonstrated. Moreover, the elastically deformed plasmonic thermal emitters demonstrate strain-dependent emission peaks, which can be applied for future mechano–thermal sensing and dynamic thermal signature modulation.Spectral and polarization engineering of thermal radiation is demonstrated using periodic metallic microstructures, created on elastomeric substrates without any fabrication tools. The elastically deformable plasmonic thermal emitters enable dynamically tunable polarized emission, which can be applied for future mechanothermal sensing and dynamic thermal signature modulation.
      PubDate: 2017-04-07T07:17:15.228047-05:
      DOI: 10.1002/adom.201600993
       
  • Compact Generation of Airy Beams with C-Aperture Metasurface
    • Authors: Eui-Young Song; Gun-Yeal Lee, Hyeonsoo Park, Kyookeun Lee, Joonsoo Kim, Jongwoo Hong, Hwi Kim, Byoungho Lee
      Abstract: A novel method to launch finite power Airy beams based on a metasurface is presented. By tailoring the amplitude and phase of the transmitted fields from a metallic C-aperture array, launching Airy beams is achieved in free space. The amplitude and phase of the Airy beam profile can be mapped and tailored by tuning only the tilt angles of the aperture. This structure has multifrequency characteristics, which facilitates Airy beam steering because the trajectory of Airy beams is dependent on the wavelength. In addition, the design method can generate Airy beams which have a very compact main lobe (≈2 µm). Computational and experimental results show that proposed metasurface can overcome some limitations of the traditional methods to generate Airy beams. The results can be used for potential applications in integrated optics, beam shaping, biosensing, and next-generation holography.A novel method to launch Airy beams based on a metasurface is presented. By tailoring the amplitude and phase of the transmitted fields from the metallic C-aperture array, launching Airy beams with very compact main lobe (≈2 µm) is achieved. This structure also has multifrequency characteristics, which facilitates Airy beam steering.
      PubDate: 2017-04-06T07:55:18.032927-05:
      DOI: 10.1002/adom.201601028
       
  • Design and Realization of a Novel Optically Disordered Material: A
           Demonstration of a Mie Glass
    • Authors: José M. Miranda-Muñoz; Gabriel Lozano, Hernán Míguez
      Abstract: Herein, a diffusive material presenting optical disorder is introduced, which represents an example of a Mie glass. Comprising spherical crystalline TiO2 nanoparticles randomly dispersed in a mesoporous TiO2 matrix, it is proved that the scattering of light in this inhomogeneous solid can be predicted in an unprecedented manner from single-particle considerations employing Mie theory. To that aim, a study of the dependence of the key parameters employed is performed to describe light propagation in random media, i.e., the scattering mean free path and the transport mean free path, as a function of the size and concentration of the spherical inclusions based on a comparison between experimental results and analytical calculations. It is also demonstrated that Mie glasses enable enhanced fluorescence intensity due to a combined absorptance enhancement of the excitation light combined with an improved outcoupling of the emitted light. The method offers the possibility to perform a deterministic design for the realization of a light diffuser with tailor-made scattering properties.Mie glasses are inhomogeneous solids that behave as solid dispersions of light scatterers. A full optical characterization of this material is performed to attain the key parameters that describe light propagation in random media. The potential of Mie glasses for color conversion is confirmed by sensitizing them with fluorescent dyes, resulting in spontaneous emission enhancement.
      PubDate: 2017-04-06T07:55:13.377726-05:
      DOI: 10.1002/adom.201700025
       
  • Assessing Early-Stage CO2 utilization Technologies—Comparing Apples
           and Oranges?
    • Authors: Arno W. Zimmermann; Reinhard Schomäcker
      Abstract: CO2 utilization involves many disciplines—fields as different as apples and oranges. Technology assessment is a common tool for evaluation. This article analyses its current state in CO2 utilization. First, the steps of chemical product development are matched with technology readiness levels (TRLs) for classification. Second, relevant literature is selected, and assessment methods and indicators are examined. The analysis shows that standardization in CO2 utilization technology assessment is low. Current research addresses some but not all assessment fields and tends to use a large range of indicators, making comparison difficult. Overall standard methods are needed as they could facilitate technology comparison and provide a better understanding of trade-offs. Future assessments should be extended to the definition of a standard set of assessment indicators, the further adoption of social impact assessment for all TRLs, and the inclusion of environmental impact assessment at early stages.Standardize strategies: CO2 utilization involves research fields as different as apples and oranges, making comparison difficult. This articles analyses how the fields are currently evaluated and suggests strategies how technology assessment in CO2 utilization could be facilitated in the future.
      PubDate: 2017-04-03T02:46:07.050514-05:
      DOI: 10.1002/ente.201600805
       
  • The Effect of Inlet Velocity on CH4 Catalytic Combustion Behavior with H2
           Addition in a Microchannel Combustor
    • Authors: Yunfei Yan; Qingyun Xu, Weimin Tang, Qiao Huang, Li Zhang, Lixian Li, Zhongqing Yang
      Abstract: The characteristics of premixed methane/air combustion in a microchannel with a Pt catalyst were examined and the effect of inlet velocity on catalytic methane combustion with hydrogen addition was investigated numerically. It is shown that appropriate hydrogen addition can expand the extinction limits, particularly the upper extinction limit of the inlet velocity, and increase methane conversion at higher inlet velocities. However, it is proved that methane conversion at an equivalent ratio of 0.8 decreased with hydrogen addition when inlet velocity was lower than 0.36 m s−1. The heat released in the hydrogen–oxygen reaction increased the wall temperature, which resulted in the adsorption–desorption equilibrium of oxygen shifting towards desorption as Pt(s) coverage increased and O(s) coverage decreased. With the same amount of hydrogen added, the changes in wall temperature that reflected the thermal effects of hydrogen were more obvious at higher inlet velocities, which improved methane conversion. If the heat released by hydrogen was neglected, the competitive consumption of oxygen, which demonstrates the chemical effect of hydrogen, was more significant at lower inlet velocities, which inhibited methane conversion.Inlet velocity matters: Hydrogen addition can expand the extinction limit. The promotive effect of increased hydrogen addition on methane conversion becomes stronger at high inlet velocity, which results from an advanced ignition position and a thermal effect of hydrogen addition. At low inlet velocity, hydrogen addition inhibits methane conversion due to a chemical effect of hydrogen on competitive oxygen consumption.
      PubDate: 2017-03-30T08:00:37.972272-05:
      DOI: 10.1002/ente.201600766
       
  • Investigation of Carbon Flows in Switzerland with the Special
           Consideration of Carbon Dioxide as a Feedstock for Sustainable Energy
           Carriers
    • Authors: Boris Meier; Fabian Ruoss, Markus Friedl
      Abstract: The substitution of fossil energy carriers by renewable hydrocarbons is a promising measure to reduce net CO2 emissions. The production of renewable hydrocarbons requires hydrogen and carbon. Although hydrogen is easily accessible, the finding of optimal carbon sources requires an understanding of natural and anthropogenic carbon flows. However, there is no overview on the entire carbon flows in Switzerland yet. Although the potential of carbon from biomass is well known, it is unknown whether CO2 is the limiting factor for the production of renewable synthetic fuels. In a comprehensive analysis, 57 carbon paths within Switzerland and across its borders are identified. The carbon flows are quantified for 2013 and illustrated in a Sankey diagram. The diagram is universal and may be applied to other countries in this form. From this analysis, optimal carbon sources for renewable fuels are found. The question is discussed of whether CO2 for synthetic renewable fuels may also originate from nonbiogenic sources. Optimal carbon sources are either biomass or CO2 from incineration plants or cement-manufacturing plants. If all accessible CO2 from these plants was used for the production of CH4, 43 % of Switzerland's road transportation could be powered with only a very low net CO2 emission if the electric power originates from renewable sources. The limiting factor for the production of synthetic fuel is renewable electrical energy rather than CO2. We propose that the origin of CO2 does not affect the sustainability of the synthetic fuel but the origin of the electric power does.Use it or lose it: We identify and illustrate 57 carbon paths in Switzerland in a Sankey diagram. Optimal carbon sources for the synthesis of renewable fuels are identified. The potential for the production of the fuels is derived. The limiting factor for the production of synthetic fuels is electrical energy rather than CO2.
      PubDate: 2017-03-30T03:59:27.869767-05:
      DOI: 10.1002/ente.201600554
       
  • Polyethylenimine Applications in Carbon Dioxide Capture and Separation:
           From Theoretical Study to Experimental Work
    • Authors: Xinhua Shen; Hongbo Du, Riley H. Mullins, Raghava R. Kommalapati
      Abstract: Solid absorbents made with polyethylenimine (PEI), which is loaded on different porous substrates, are promising for postcombustion carbon dioxide capture. Herein, theoretical studies of polyamine applications, including PEI for carbon dioxide capture, are reviewed and the development of experimental work on carbon dioxide capture by using PEI summarized. The mechanisms of carbon dioxide capture are discussed at different reaction sites of the polyamines, such as primary, secondary, and tertiary amine groups. Experimental achievements in carbon dioxide capture are investigated by the incorporation of PEI with different support materials, such as mesoporous silica; nanotubes; membranes; and other materials, such as alumina, zeolite, resin, metal–organic frameworks, and glass fibers, through impregnation, grafting, and synthesis. The excellent carbon dioxide capture capacity and great stability of PEI-impregnated nanomaterials highlight PEI as one of the greatest candidates for carbon dioxide capture from flue gas or air.Impregnating adsorbents: Polyethylenimine (PEI)-functionalized solid adsorbents and membranes are promising for carbon dioxide (CO2) capture and separation from flue gas or air. The review discusses the mechanism of CO2 capture with PEI from theoretical studies and summarizes the performance of CO2 capture and separation with PEI-functionalized silica, nanotubes, membranes, and other low-cost materials (nano- and macrosized) from experimental work.
      PubDate: 2017-03-30T03:50:46.348653-05:
      DOI: 10.1002/ente.201600694
       
  • Liquid Metals as Efficient High-Temperature Heat-Transport Fluids
    • Authors: Annette Heinzel; Wolfgang Hering, Jürgen Konys, Luca Marocco, Karsten Litfin, Georg Müller, Julio Pacio, Carsten Schroer, Robert Stieglitz, Leonid Stoppel, Alfons Weisenburger, Thomas Wetzel
      Abstract: Liquid metals appear to be attractive heat-transport fluids, in particular if looking at their high thermal conductivities and low viscosities. Despite some pioneering technical applications in the past, complex handling, special requirements, safety concerns, and structural degradation of the materials have prevented their widespread application. However, progress in research and development on liquid-metal science and technology has advanced considerably in the last decade, and this has opened the gate to their broader use in the short term. This requires a more differentiated view on liquid metals, particularly on the specific properties of individual fluids within the context of specific applications. By doing so, many commonly mentioned prejudices vanish or are of minor significance. At the Karlsruhe Institute of Technology, a comprehensive research program on liquid-metal technology has been pursued for more than 50 years, and some of the advances in different applications will be outlined in this article.Liquid assets: Liquid metals appear to be attractive heat-transport fluids, in particular if looking at their high thermal conductivities and low viscosities. At the Karlsruhe Institute of Technology, a comprehensive research program on liquid-metal technology has been pursued for more than 50 years, and some of the advances in different applications are outlined herein.
      PubDate: 2017-03-29T09:16:03.341028-05:
      DOI: 10.1002/ente.201600721
       
  • Liquid Metals as Efficient High-Temperature Heat-Transport Fluids
    • Authors: Annette Heinzel; Wolfgang Hering, Jürgen Konys, Luca Marocco, Karsten Litfin, Georg Müller, Julio Pacio, Carsten Schroer, Robert Stieglitz, Leonid Stoppel, Alfons Weisenburger, Thomas Wetzel
      Abstract: Liquid metals appear to be attractive heat-transport fluids, in particular if looking at their high thermal conductivities and low viscosities. Despite some pioneering technical applications in the past, complex handling, special requirements, safety concerns, and structural degradation of the materials have prevented their widespread application. However, progress in research and development on liquid-metal science and technology has advanced considerably in the last decade, and this has opened the gate to their broader use in the short term. This requires a more differentiated view on liquid metals, particularly on the specific properties of individual fluids within the context of specific applications. By doing so, many commonly mentioned prejudices vanish or are of minor significance. At the Karlsruhe Institute of Technology, a comprehensive research program on liquid-metal technology has been pursued for more than 50 years, and some of the advances in different applications will be outlined in this article.Liquid assets: Liquid metals appear to be attractive heat-transport fluids, in particular if looking at their high thermal conductivities and low viscosities. At the Karlsruhe Institute of Technology, a comprehensive research program on liquid-metal technology has been pursued for more than 50 years, and some of the advances in different applications are outlined herein.
      PubDate: 2017-03-29T09:16:03.341028-05:
      DOI: 10.1002/ente.201600721
       
  • Large-Scale Robust Quantum Dot Microdisk Lasers with Controlled High
           Quality Cavity Modes
    • Authors: Chun Hao Lin; Qingji Zeng, Evan Lafalce, Marcus J. Smith, Sidney T. Malak, Jaehan Jung, Young Jun Yoon, Zhiqun Lin, Zeev Valy Vardeny, Vladimir V. Tsukruk
      Abstract: This study reports a facile on-chip fabrication of CdSe/Cd1−xZnxSe1−ySy quantum dot microdisk lasers and their large-area arrays via a pattern-assisted layer-by-layer assembly process. This approach combines the versatility of colloidal semiconducting nanoparticles (bright emission, solubility, and high stability) with the spatial precision of optical lithography to create robust large-area optical lasing arrays (up to a few thousand disks). Specifically, microdisk lasers with high quality factors (within 1000–2000) are fabricated with predefined size and shape (as controlled by master templates) with high consistency and throughput, essentially providing a new approach to fabricate difficult-to-control on-chip optical cavities in a low-cost and effective manner. Notably, the number of longitudinal cavity modes in the microdisk laser can be precisely controlled by varying the microdisks' diameter, allowing for either near-single mode or multimode operation while preserving high quality factors. Furthermore, the cross-linking of quantum dots imparts high chemical resistance and mechanical robustness that helps retain the structural integrity under harsh processing conditions (such as sonication or direct exposure to various solvents). As such, these quantum dot microdisk laser arrays are promising candidates for advancing the development of large-area, low-cost on-chip photonic structures with controlled lasing modes.Facile fabrication of on-chip CdSe/Cd1−xZnxSe1−ySy quantum dot microdisk lasers via pattern-assisted layer-by-layer assembly is demonstrated. This method allows for a definable disk size and subsequent controllable cavity modes with high quality factors of 1000–2000.
      PubDate: 2017-03-29T08:28:49.676312-05:
      DOI: 10.1002/adom.201700011
       
  • Control of the Stokes Shift with Strong Coupling
    • Authors: Ekembu K. Tanyi; Hannah Thuman, Nicolas Brown, Samantha Koutsares, Viktor A. Podolskiy, Mikhail A. Noginov
      Abstract: Strong coupling of excitons in macroscopic ensembles of quantum emitters and cavities (or surface plasmons) can lead to dramatic change of the optical properties and modification of the dispersion curves, characterized by the normal mode splitting of the order of 1 eV. Such gigantic alteration of the hybrid energy states enables scores of unparalleled physical phenomena and functionalities, ranging from enhancement of electrical conductivity to control of chemical reactions. While coupling of single emitters to a cavity is a pure quantum mechanical phenomenon, the origin of the strong coupling involving large ensembles of molecules is the subject of controversy. In this work, the strong coupling of rhodamine 6G dye molecules with silver Fabry–Perot cavities is studied and the significant increase of the Stokes shift between the excitation and the emission bands of hybridized molecules is demonstrated. The proposed empirical model of the underlying physics calls for the quantum mechanical parity selection rule.In this work, the strong coupling of rhodamine 6G dye molecules with silver Fabry–Perot cavities is studied and the significant increase of the Stokes shift between the excitation and the emission bands of hybridized molecules is demonstrated. The proposed empirical model of the underlying physics calls for the quantum mechanical parity selection rule.
      PubDate: 2017-03-29T08:25:44.320507-05:
      DOI: 10.1002/adom.201600941
       
  • Lasing from Organic Dye Molecules Embedded in Transparent Wood
    • Authors: Elena Vasileva; Yuanyuan Li, Ilya Sychugov, Mounir Mensi, Lars Berglund, Sergei Popov
      Abstract: The report on a study of laser emission from a conceptually new organic material based on transparent wood (TW) with embedded dye Rhodamine 6G molecules is presented in this paper. The lasing performance is compared to a reference organic material containing dye in a poly-methyl-methacrylate matrix. From experimental results, one can conclude that the optical feedback in dye-TW material is realized within cellulose fibers, which play the role of tiny optical resonators. Therefore, the output emission is a collective contribution of individual resonators. Due to this fact, as well as low Q-factor of the resonators/fibers and their length variation, the spectral line of laser emission is broadened up to several nanometers.Lasing from transparent wood matrix with embedded dye molecules is experimentally demonstrated. The material has not only unique nature, but also possesses fascinating optical properties due to its cellulose-fiber-based structure. In particular, such fibers work as tiny resonators, which in a combination with optical gain media (dye) are responsible for the laser light generation.
      PubDate: 2017-03-29T07:46:01.033594-05:
      DOI: 10.1002/adom.201700057
       
  • Enhanced Carrier Multiplication in InAs Quantum Dots for Bulk Avalanche
           Photodetector Applications
    • Authors: Ying-Jie Ma; Yong-Gang Zhang, Yi Gu, Xing-You Chen, Peng Wang, Bor-Chau Juang, Alan Farrell, Bao-Lai Liang, Diana L. Huffaker, Yan-Hui Shi, Wan-Yan Ji, Ben Du, Su-Ping Xi, Heng-Jing Tang, Jia-Xiong Fang
      Abstract: Exploring the potentiality of enhancing the performance of avalanche photodiodes (APDs) using novel nanoscale structures is highly attractive for overcoming the bottleneck of avalanche probability. This work demonstrates, for the first time, multiplication enhancement of electron-initiated photocurrent due to impact ionization in InAs quantum dots (QDs) within a GaAs APD structure. A five-layer stacked 2.25 MLs InAs QD/50 nm GaAs spacer multiplication structure integrated into a separated absorption, charge, and multiplication GaAs homo APD results in up to six times higher multiplication factors in comparison to a reference device without QD over a temperature range of 77–300 K. In addition, extremely low excess noise factor in close proximity to that of silicon is also observed with an effective keff factor below 0.1. This demonstration is of fundamental interest and relevant for future ultra efficient avalanche detector applications.Up to six times higher multiplication factors in comparison to a reference device and extremely low excess noise factor in close proximity to that of silicon with a keff factor below 0.1 are achieved in epitaxial InAs quantum dots under a strong electric field for bulk GaAs avalanche photodetector applications.
      PubDate: 2017-03-29T01:31:13.559716-05:
      DOI: 10.1002/adom.201601023
       
  • Pt-Nanostrip-Enabled Plasmonically Enhanced Broad Spectral Photodetection
           in Bilayer MoS2
    • Authors: Rahul Kumar; Alka Sharma, Mandeep Kaur, Sudhir Husale
      Abstract: Hot electron injection in 2D layered materials, in particular graphene or transition metal dichalcogenides, has been the subject of intense research in recent years. The coupling of plasmonic nanostructures with the nanolayers of 2D materials enhances the optoelectronic properties even beyond the bandgap of the material and depends on the tuning of the plasmonic nanomaterials used. In contrast to the Au/Ag mostly used in plasmonic nanostructures, Pt/Pd are more promising for the design of future nano-plasmonic devices due to their strong catalytic activities and they exhibit a broad localized surface plasmon resonance. Here, plasmonic enhancements in the photoconductivity of bilayer MoS2 induced by Pt nanostrips are reported. About three orders of change in the photocurrent was observed when the plasmonic Pt nanostrips were integrated with the MoS2 and this was measured under illumination with a 532-nm laser. The fabricated MoS2 devices with Pt nanostrips demonstrated a sensitivity to UV, visible, and NIR light. Numerical analysis shows that the platinum nanostrips exhibit better absorption properties over a broader range of the light spectrum. The electric field enhancements observed at 532 nm and 980 nm clearly indicate that MoS2-based nanodevices can be tuned with Pt plasmonic nanostructures to achieve high-performance, ultra-compact, optoelectronic devices with excellent plasmonic and catalytic activities.High-performance photoresponsivity over a broad spectral range is found in MoS2 devices that are integrated with plasmonic platinum nanostrips. These nanodevices can find many useful applications in photon harvesting, hydrogen evolution reactions, and other catalytic processes where enhanced localized fields are in demand.
      PubDate: 2017-03-29T01:31:06.111982-05:
      DOI: 10.1002/adom.201700009
       
  • pH Dependent Optical Switching and Fluorescence Modulation of Molybdenum
           Sulfide Quantum Dots
    • Authors: Himanshu Mishra; Sima Umrao, Jai Singh, Rajesh Kumar Srivastava, Rashid Ali, Arvind Misra, Anchal Srivastava
      Abstract: Investigations on fluorescent molecules with fluorescence switching behavior as function of pH, temperature, ion concentration, etc. is highly desirable in the field of sensor device fabrication. In this study, the authors report an easy and eco-friendly hydrothermal route for the synthesis of pH dependent fluorescent MoS2 quantum dots (MoS2-QDs). The average size of the synthesized QDs is found to be ≈7 nm which was confirmed with transmission electron microscopy and atomic force microscopy. These MoS2-QDs show the pH dependent fluorescence switching behavior. Under pH ≈ 1 the fluorescence intensity of the MoS2-QDs is quenched while it shows ≈200 times enhancement under pH ≈ 13. This florescence ON/OFF switching is mainly due to the surface adsorbed functional groups (NH2, SO42−, OH−, etc.) and is a combined effect viz. protonation–deprotonation process, acid etching, quantum confined Stark effect and particle agglomeration. A plausible mechanism for this pH dependent ON/OFF switching behavior is also discussed in this study. The band gap calculation under different pH environment is also in good agreement to the hypothesis.In this study MoS2-quantum dots (QDs) are synthesized by using a facile and eco-friendly hydrothermal method using sodium molybdate and l-cysteine as starting materials. These MoS2-QDs show pH dependent optical switching and fluorescence modulation behavior.
      PubDate: 2017-03-29T01:25:44.599028-05:
      DOI: 10.1002/adom.201601021
       
  • Spatial Confinement of Light onto a Flat Metallic Surface Using
           Hybridization between Two Cavities
    • Authors: Adam Weissman; Matan Galanty, David Gachet, Elad Segal, Omer Shavit, Adi Salomon
      Abstract: Controlling the optical field down to the nanometer scale is a key step in optoelectronic applications and light–matter interaction at the nanoscale. Bowtie structures, rods, and sharp tapers are commonly used to realize such optical properties, but their fabrication is challenging. In this context, the complementary structures, namely, holes and cavities, are less explored. Herein, a simple system of two metallic nanocavities milled in thin silver film is used to confine the electromagnetic field to an area of ≈60 nm2. The field is confined onto a flat surface area and is either enhanced or suppressed by the polarization state of incident light. The energy of this spatially confined mode is determined by the distance between the two cavities and thus any color (wavelength) at the optical regime can be achieved. As a consequence, a dynamically controlled color is generated on an optical pixel size smaller than 1 µm2. Those results are supported by both transmission spectra and a cathodoluminescence study.A simple system of two nanocavities is used to confine the electromagnetic field to a ≈60 nm2 area onto a metallic surface. The energy of this confined mode is determined by the distance between the cavities and any color (wavelength) at the optical regime is achieved. A dynamically controlled color is generated on a micrometer-size optical pixel.
      PubDate: 2017-03-29T01:25:38.550797-05:
      DOI: 10.1002/adom.201700097
       
  • Actively Tunable Structural Color Rendering with Tensile Substrate
    • Authors: Shichao Song; Xiaoliang Ma, Mingbo Pu, Xiong Li, Kaipeng Liu, Ping Gao, Zeyu Zhao, Yanqin Wang, Changtao Wang, Xiangang Luo
      Abstract: Dynamic color tuning is a very important and fascinating direction in the field of structural colorations due to its possible applications in stealth, anticounterfeiting, displaying techniques, etc. However, the most recent work about structural colors either have limitations on dynamic frequency tunability or require special conditions. In this work, a tensile substrate (e.g., polydimethylsiloxane) is introduced into conventional plasmonic structures to demonstrate dynamic tunable structural colors. The proposed idea is experimentally realized by fabricating samples via interference photolithography. The results show that resonance-induced colors can be dynamically tuned from green to fuchsia by stretching the tensile substrate. Moreover, a further thematic analysis of the physical mechanism in the proposed structure is conducted. The authors envisage that their method has potential applications in anticounterfeiting, biometric sensors, and mechanics measurements.A tensile substrate is introduced into the conventional plasmonic structure to propose an effective method for tunable structural colors. By controlling the external force, color varying from green to fuchsia is achieved. The presented findings may have great potential applications in displays, biometric sensors, and mechanics measurement, etc.
      PubDate: 2017-03-29T01:25:30.541425-05:
      DOI: 10.1002/adom.201600829
       
  • Plasmonic Sensing of Oncoproteins without Resonance Shift Using 3D
           Periodic Nanocavity in Nanocup Arrays
    • Authors: Abid Ameen; Lisa P. Hackett, Sujin Seo, Faiza Khawar Dar, Manas R. Gartia, Lynford L. Goddard, Gang Logan Liu
      Abstract: A sensor design and sensing method based on plasmonic–photonic interactions that occur when a nanocavity array is embedded in a 3D tapered nanocup plasmonic substrate are reported. This device enables highly sensitive detection of refractive index changes based on changes to the transmission peak intensity without shift in the resonance wavelength. Unlike conventional plasmonic sensors, there is a consistent and selective change in the transmission intensity at the resonance peak wavelength with no spectral shift. In addition, there are wavelength ranges that show no intensity change, which can be used as reference regions. The fabrication and characterization of the plasmonic nanocavity sensor are described and also advanced biosensing is demonstrated. Simulations are carried out to better understand the plasmon–photonic coupling mechanism. This nanocavity plasmonic sensor design has a limit of detection of 1 ng mL−1 (5 × 10−12m) for the cancer biomarker carcinoembryonic antigen (CEA), which is a significant improvement over current surface plasmon resonance systems, and a dynamic range that is clinically relevant for human CEA levels.A multilayered nanocavity embedded in a nanocup array shows a new plasmonic refractive index sensing mechanism based on sensitive intensity variation with no plasmon resonance peak shift. Using this device, a limit of detection of 1 ng mL−1 (5 × 10−12m) for the cancer biomarker carcinoembryonic antigen (CEA) and a dynamic range that is clinically relevant for human CEA levels are demonstrated.
      PubDate: 2017-03-29T01:20:50.117516-05:
      DOI: 10.1002/adom.201601051
       
  • Bioinspired Adaptive Microplate Arrays for Magnetically Tuned Optics
    • Authors: Shanshan Liu; Yue Long, Chuanyong Liu, Zhijian Chen, Kai Song
      Abstract: In this work, magnetic field driven polymer microplate arrays are fabricated to modulate the optical properties of the sample, i.e. reflectance and fluorescence. Inspired by poplar leaves, which rotate the high reflectance white side of the leave upwards to act as a “roof” under strong light radiation, and switch the low reflectance green side for photosynthesis back again when the light is less severe. In this study, gold was selectively deposited on one side of the microplate, and surface reflectivity can be reversibly switched from higher to lower state through the change of the magnetic field direction to bend the microplates with the gold side facing up and down. The modulation of fluorescence emission is realized by magnetically control the tilting angle of the microplates, in the same way as a venetian blind. The fluorescence intensity reaches its maximum and minimum at the perpendicular and parallel position to the fluorescent substrate, respectively. This system provides a fast responding and remote controllable means to modulate the optical properties of samples, which has been considered important in certain applications, such as smart reflectors, environmentally friendly windows, and field emission.Magnetic field driven polydimethylsiloxane microplate arrays are fabricated to modulate the optical properties, i.e., reflectance and fluorescence. Surface reflectivity is switched from higher state to low by bending the microplates with the high reflective side facing up and down. The fluorescence emission of the surface can be continuously adjusted by tilting the microplates to different angles like a venetian blind.
      PubDate: 2017-03-29T01:20:39.743344-05:
      DOI: 10.1002/adom.201601043
       
  • Titania Nanotubes Decorated with Zn-Doped Titania Nanoparticles as the
           Photoanode Electrode of Dye-Sensitized Solar Cells
    • Authors: H. Mokarami Ghartavol; A. Afshar, M. R. Mohammadi, F. Chau-Nan Hong, Yeau-Ren Jeng
      Abstract: We decorated Zn-doped TiO2-nanoparticle-based photoanodes with carbon nanotube (CNT)-derived TiO2 nanotubes (TNs) to enhance the power conversion efficiency of dye-sensitized solar cells (DSCs). X-ray photoelectron spectroscopy analysis verified that Zn ions, in the range of 0 to 1 at %, were successfully doped into the TiO2 lattice. Field-emission SEM and TEM images of the TNs, as derived from the sol–gel template-assisted route, revealed that a uniform TiO2 coating with a thickness of 60 to 120 nm was deposited on the surface of the CNT template through a noncovalent route. We observed that the cell efficiency improved from 6.80 for pure TiO2 to 7.52 for 0.75 at % Zn-doped TiO2 nanoparticles due to a reduction in charge recombination and enhancement in electron injection, as confirmed by using photoluminescence spectroscopy. Further improvements in the efficiency of up to 8.47 % were achieved by the incorporation of 5 wt % TNs into the Zn-doped TiO2 photoanodes, as a result of enhancements in electron transport and light scattering, which was verified by using diffuse reflectance spectroscopy.Titania nanotubes for anodes: Benzyl alcohol was used as a surfactant to enable TiO2 to interact with the hydrophobic surface of pristine carbon nanotubes (CNT) without the need for covalent functionalization. The CNT-derived TiO2 nanotubes were incorporated into Zn-doped TiO2 photoanodes as the photoanode of dye-sensitized solar cells to control electron injection, electron transport, charge recombination, and light scattering of the photoelectrode.
      PubDate: 2017-03-27T01:55:31.259581-05:
      DOI: 10.1002/ente.201600786
       
  • Titania Nanotubes Decorated with Zn-Doped Titania Nanoparticles as the
           Photoanode Electrode of Dye-Sensitized Solar Cells
    • Authors: H. Mokarami Ghartavol; A. Afshar, M. R. Mohammadi, F. Chau-Nan Hong, Yeau-Ren Jeng
      Abstract: We decorated Zn-doped TiO2-nanoparticle-based photoanodes with carbon nanotube (CNT)-derived TiO2 nanotubes (TNs) to enhance the power conversion efficiency of dye-sensitized solar cells (DSCs). X-ray photoelectron spectroscopy analysis verified that Zn ions, in the range of 0 to 1 at %, were successfully doped into the TiO2 lattice. Field-emission SEM and TEM images of the TNs, as derived from the sol–gel template-assisted route, revealed that a uniform TiO2 coating with a thickness of 60 to 120 nm was deposited on the surface of the CNT template through a noncovalent route. We observed that the cell efficiency improved from 6.80 for pure TiO2 to 7.52 for 0.75 at % Zn-doped TiO2 nanoparticles due to a reduction in charge recombination and enhancement in electron injection, as confirmed by using photoluminescence spectroscopy. Further improvements in the efficiency of up to 8.47 % were achieved by the incorporation of 5 wt % TNs into the Zn-doped TiO2 photoanodes, as a result of enhancements in electron transport and light scattering, which was verified by using diffuse reflectance spectroscopy.Titania nanotubes for anodes: Benzyl alcohol was used as a surfactant to enable TiO2 to interact with the hydrophobic surface of pristine carbon nanotubes (CNT) without the need for covalent functionalization. The CNT-derived TiO2 nanotubes were incorporated into Zn-doped TiO2 photoanodes as the photoanode of dye-sensitized solar cells to control electron injection, electron transport, charge recombination, and light scattering of the photoelectrode.
      PubDate: 2017-03-27T01:55:31.259581-05:
      DOI: 10.1002/ente.201600786
       
  • Effects of Interlayer Coupling on Hot Carrier Dynamics in Graphene-Derived
           van der Waals Heterostructures
    • Authors: Prineha Narang; Litao Zhao, Steven Claybrook, Ravishankar Sundararaman
      Abstract: Graphene exhibits promise as a plasmonic material with high mode confinement that could enable efficient hot carrier extraction. The lifetimes and mean free paths of energetic carriers have been investigated in free-standing graphene, graphite, and a heterostructure consisting of alternating graphene and hexagonal boron nitride layers using ab initio calculations of electron–electron and electron–phonon scattering in these materials. It is found that the extremely high lifetimes (3 ps) of low-energy carriers near the Dirac point in graphene, which are a 100 times larger than that in noble metals, are reduced by an order of magnitude due to interlayer coupling in graphite, but enhanced in the heterostructure due to phonon mode clamping. However, these lifetimes drop precipitously with increasing carrier energy and are smaller than those in noble metals at energies exceeding 0.5 eV. By analyzing the contribution of different scattering mechanisms and interlayer interactions, desirable spacer layer characteristics—high dielectric constant and heavy atoms—that could pave the way for plasmonic heterostructures with improved hot carrier transport have been identified.Hot carrier life times in graphene-based heterostructures exceed those in noble metals such as silver by two orders of magnitude for carriers close to the Fermi level. Carrier lifetimes decrease more rapidly with energy in these materials due to optical-phonon scattering and fall below those in silver 0.5 eV away from the Fermi level.
      PubDate: 2017-03-24T07:35:27.509737-05:
      DOI: 10.1002/adom.201600914
       
  • Synthesis and Electrochemical Properties of Hierarchically Porous
           Zn(Co1−xMnx)2O4 Anodes for Li-Ion Batteries
    • Authors: Wei-Ting Wong; Bing-Hong Chen, Irish Valerie B. Maggay, Chang Liu, Jenq-Gong Duh, Wei-Ren Liu
      Abstract: A hierarchically porous Zn(Co1−xMnx)2O4 anode is synthesized through a hydrothermal method. XRD measurements indicate that ZnCo2O4, ZnCo1.5Mn0.5O4, ZnCoMnO4, ZnCo0.5Mn1.5O4, and ZnMn2O4 are isostructural in solid solution. Through analysis of X-ray photoelectronic spectra and EPMA and EDX mapping of Zn(Co1−xMnx)2O4, it is confirmed that the valance of Mn is 3+ only, and that the Mn cation is distributed homogeneously in the ZnCo2O4-based structure. Interestingly, the pore-size distributions of these spinel-based anodes are tunable by changing the substituting content of Mn in the ZnCo2O4 host. Compared with nanoporous ZnCo2O4 and macroporous ZnMn2O4, the as-synthesized ZnCoMnO4 nanospheres exhibit a high capacity of 823 mAh g−1 with excellent cycling retention of more than 80 cycles without decay. The excellent cyclability might be attributed to the nanosized particles and the nature of the hierarchical pore-size distribution. The results indicate that ZnCoMnO4 is a good candidate as an anode for application in lithium-ion batteries.Improving the anode: Zn(Mn1−xCox)2O4 is synthesized through a hydrothermal method. The composition-optimized ZnMnCoO4 anode exhibits a high capacity of 823 mAh g−1 with excellent cycling retention.
      PubDate: 2017-03-24T04:45:48.685353-05:
      DOI: 10.1002/ente.201600634
       
  • Impact of White Light Illumination on the Electronic and Chemical
           Structures of Mixed Halide and Single Crystal Perovskites
    • Authors: Feng-Shuo Zu; Patrick Amsalem, Ingo Salzmann, Rong-Bin Wang, Maryline Ralaiarisoa, Stefan Kowarik, Steffen Duhm, Norbert Koch
      Abstract: This study investigates the effect of white light illumination on the electronic and chemical properties of mixed halide perovskite (CH3NH3PbI3−xClx) thin films and CH3NH3PbI3 single crystals using photoelectron and absorption spectroscopy. The pristine materials' surfaces are found to be n-type because of surface band bending due to the presence of donor levels, likely consisting of reduced lead (Pb0) that acts as surface traps. When illuminating the sample with white light (up to 1 sun), the valence features shifted to lower binding energy due to surface photovoltage, i.e., the bulk of the materials is much less n-type. However, the surface photovoltage is only partially reversible and vanishes for prolonged illumination time. Concomitantly, a high concentration of metallic Pb0 is found, which induces strong Fermi-level pinning and quenching of the surface photovoltage. This is accompanied also by the formation of PbI2 defects. Similar experiments on single crystals reveal the presence of a high concentration of reduced (metallic) Pb0 at the sample surface after cleaving. The present findings indicate that the chemical and electronic properties of perovskite films are very sensitive to white light illumination. Accounting for these light-induced material changes is important to fully understand its photophysical properties and for improving the lifetime of perovskite-based devices.The electronic and chemical properties of perovskites are significantly affected upon white light illumination. Trap states, mainly consisting of elemental lead, pin the Fermi level at the surface of mixed halide and single crystal perovskites, giving rise to the surface n-type behavior. Concomitantly, iodine deficiency and the emergence of PbI2 are also observed.
      PubDate: 2017-03-24T04:05:39.480176-05:
      DOI: 10.1002/adom.201700139
       
  • Montmorillonite-Supported Iron Oxide for Hydrogen Storage by Chemical
           Looping
    • Authors: Zhong Ma; Rui Xiao, Huiyan Zhang
      Abstract: A technology for hydrogen storage is proposed based on the repeated reduction of magnetite (Fe3O4+4 H23 Fe+4 H2O) and the oxidization of metallic iron (3 Fe+4 H2OFe3O4+4 H2). Herein, we prepared three montmorillonite (MMT)-supported iron oxide samples by using a sol–gel method and demonstrated their application in hydrogen storage through a chemical looping process. The redox performance of the Fe-MMT samples was studied at 600 °C in a fixed-bed reactor. The results showed that 70 Fe-MMT (with 70 wt % Fe2O3) exhibited relatively good redox performance owing to its excellent anti-agglomeration ability and sintering resistance. After the redox performance tests, Fe2SiO4 was observed in all Fe-MMT samples. It was worth noting that the diffraction intensity of Fe2SiO4 in 70 Fe-MMT was much weaker than in 30 Fe-MMT (30 wt % Fe2O3) and 50 Fe-MMT (50 wt % Fe2O3), which was owed to the high MMT content in the 30 Fe-MMT and 50 Fe-MMT samples. The formation of Fe2SiO4 in repeated redox cycles could reduce the stability and recyclability of Fe-MMT samples. This might be the major reason for the better hydrogen storage performance of 70 Fe-MMT compared with 30 Fe-MMT and 50 Fe-MMT.Strong electrostatic forces: Iron oxide supported on montmorillonite is synthesized by using a sol–gel method and used for hydrogen storage by chemical looping. This compound exhibited excellent sintering resistance due to the strong electrostatic force between the iron oxide and the montmorillonite.
      PubDate: 2017-03-23T08:45:45.085864-05:
      DOI: 10.1002/ente.201600697
       
  • Montmorillonite-Supported Iron Oxide for Hydrogen Storage by Chemical
           Looping
    • Authors: Zhong Ma; Rui Xiao, Huiyan Zhang
      Abstract: A technology for hydrogen storage is proposed based on the repeated reduction of magnetite (Fe3O4+4 H23 Fe+4 H2O) and the oxidization of metallic iron (3 Fe+4 H2OFe3O4+4 H2). Herein, we prepared three montmorillonite (MMT)-supported iron oxide samples by using a sol–gel method and demonstrated their application in hydrogen storage through a chemical looping process. The redox performance of the Fe-MMT samples was studied at 600 °C in a fixed-bed reactor. The results showed that 70 Fe-MMT (with 70 wt % Fe2O3) exhibited relatively good redox performance owing to its excellent anti-agglomeration ability and sintering resistance. After the redox performance tests, Fe2SiO4 was observed in all Fe-MMT samples. It was worth noting that the diffraction intensity of Fe2SiO4 in 70 Fe-MMT was much weaker than in 30 Fe-MMT (30 wt % Fe2O3) and 50 Fe-MMT (50 wt % Fe2O3), which was owed to the high MMT content in the 30 Fe-MMT and 50 Fe-MMT samples. The formation of Fe2SiO4 in repeated redox cycles could reduce the stability and recyclability of Fe-MMT samples. This might be the major reason for the better hydrogen storage performance of 70 Fe-MMT compared with 30 Fe-MMT and 50 Fe-MMT.Strong electrostatic forces: Iron oxide supported on montmorillonite is synthesized by using a sol–gel method and used for hydrogen storage by chemical looping. This compound exhibited excellent sintering resistance due to the strong electrostatic force between the iron oxide and the montmorillonite.
      PubDate: 2017-03-23T08:45:45.085864-05:
      DOI: 10.1002/ente.201600697
       
  • A Thermodynamic Study of Aqueous 1-Allyl-3-Methylimidazolium Formate Ionic
           Liquid as a Tailored Sorbent for Carbon Dioxide Separation
    • Authors: Yujiao Xie; Dilip G. Raut, Rakesh Samikannu, Jyri-Pekka Mikkola, Xiaoyan Ji
      Abstract: In this work, aqueous 1-allyl-3-methylimidazolium formate ([Amim][HCOO]) was studied as a potential sorbent for CO2 separation. The density and viscosity of aqueous [Amim][HCOO] were measured at temperatures ranging from 293.15 to 333.15 K at atmospheric pressure. The solubility of CO2 and CH4 in dry [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] were measured at pressures up to 1.8 MPa and temperatures of 298.2, 313.2, and 333.2 K. The results showed that the density and viscosity of aqueous [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] decreased upon increasing the water concentration and temperature. The viscosity was very sensitive to the water concentration. The experimental density and viscosity of aqueous [Amim][HCOO] were fitted to semiempirical equations, and the excess molar volume and viscosity deviations were calculated to investigate the interaction between the [Amim][HCOO] ionic liquid and water. The experimental vapor–liquid equilibrium was represented with the nonrandom two-liquid and Redlich–Kwong model. The model parameters can be further implemented into Aspen Plus software to conduct process simulations.Soaking it all in: A thermodynamic study is performed to investigate 1-allyl-3-methylimidazolium formate ([Amim][HCOO]) as a liquid sorbent for CO2 separation. The properties and gas solubility in aqueous [Amim][HCOO] are studied.
      PubDate: 2017-03-23T08:45:42.083192-05:
      DOI: 10.1002/ente.201600742
       
  • A Thermodynamic Study of Aqueous 1-Allyl-3-Methylimidazolium Formate Ionic
           Liquid as a Tailored Sorbent for Carbon Dioxide Separation
    • Authors: Yujiao Xie; Dilip G. Raut, Rakesh Samikannu, Jyri-Pekka Mikkola, Xiaoyan Ji
      Abstract: In this work, aqueous 1-allyl-3-methylimidazolium formate ([Amim][HCOO]) was studied as a potential sorbent for CO2 separation. The density and viscosity of aqueous [Amim][HCOO] were measured at temperatures ranging from 293.15 to 333.15 K at atmospheric pressure. The solubility of CO2 and CH4 in dry [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] were measured at pressures up to 1.8 MPa and temperatures of 298.2, 313.2, and 333.2 K. The results showed that the density and viscosity of aqueous [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] decreased upon increasing the water concentration and temperature. The viscosity was very sensitive to the water concentration. The experimental density and viscosity of aqueous [Amim][HCOO] were fitted to semiempirical equations, and the excess molar volume and viscosity deviations were calculated to investigate the interaction between the [Amim][HCOO] ionic liquid and water. The experimental vapor–liquid equilibrium was represented with the nonrandom two-liquid and Redlich–Kwong model. The model parameters can be further implemented into Aspen Plus software to conduct process simulations.Soaking it all in: A thermodynamic study is performed to investigate 1-allyl-3-methylimidazolium formate ([Amim][HCOO]) as a liquid sorbent for CO2 separation. The properties and gas solubility in aqueous [Amim][HCOO] are studied.
      PubDate: 2017-03-23T08:45:42.083192-05:
      DOI: 10.1002/ente.201600742
       
  • Investigation of a High-Performance Nanofiber Cathode with Ultralow
           Platinum Loading for Proton Exchange Membrane Fuel Cells
    • Authors: Shaojing Hong; Ming Hou, Yu Xiao, Zhigang Shao, Baolian Yi
      Abstract: Nanofiber electrodes fabricated by using the electrospinning technique in the cathode of proton exchange membrane fuel cells gave a peak power density of 0.692 W cm−2 with an ultralow Pt loading of 0.087 mg cm−2. As the cathode, the electrospun (E_spun) electrodes exposed a high Pt surface to oxygen, with a highly uniform distribution of Pt catalyst and Nafion ionomer, which improved the utilization of Pt. The ionic resistance of the E_spun electrode was decreased owing to the nanofiber structure. The high porosity of the E_spun electrode enhanced the Knudsen diffusion in small pores, which mitigated the oxygen-transfer resistance. The addition of 5 wt % polytetrafluoroethylene (PTFE) to the E_spun electrode optimized water management, especially at high current densities. The accelerated stability test showed that the long-term durability of the E_spun electrode is much better than the conventional decal electrode due to the interaction of the carbon support and hydrophilic poly(acrylic acid).All about the spin: A high-performance nanofiber electrode, fabricated by electrospinning, gives a peak power density of 0.692 W cm−2 with an ultralow Pt loading of 0.087 mg cm−2. The use of the Pt catalyst and the proton conductivity in the electrode are enhanced due to the nanofiber structure. Addition of 5 wt % polytetrafluoroethylene (PTFE) and the high porosity of the electrospun electrode optimizes water management and improves cell performance.
      PubDate: 2017-03-23T08:40:27.568382-05:
      DOI: 10.1002/ente.201600734
       
  • Investigation of a High-Performance Nanofiber Cathode with Ultralow
           Platinum Loading for Proton Exchange Membrane Fuel Cells
    • Authors: Shaojing Hong; Ming Hou, Yu Xiao, Zhigang Shao, Baolian Yi
      Abstract: Nanofiber electrodes fabricated by using the electrospinning technique in the cathode of proton exchange membrane fuel cells gave a peak power density of 0.692 W cm−2 with an ultralow Pt loading of 0.087 mg cm−2. As the cathode, the electrospun (E_spun) electrodes exposed a high Pt surface to oxygen, with a highly uniform distribution of Pt catalyst and Nafion ionomer, which improved the utilization of Pt. The ionic resistance of the E_spun electrode was decreased owing to the nanofiber structure. The high porosity of the E_spun electrode enhanced the Knudsen diffusion in small pores, which mitigated the oxygen-transfer resistance. The addition of 5 wt % polytetrafluoroethylene (PTFE) to the E_spun electrode optimized water management, especially at high current densities. The accelerated stability test showed that the long-term durability of the E_spun electrode is much better than the conventional decal electrode due to the interaction of the carbon support and hydrophilic poly(acrylic acid).All about the spin: A high-performance nanofiber electrode, fabricated by electrospinning, gives a peak power density of 0.692 W cm−2 with an ultralow Pt loading of 0.087 mg cm−2. The use of the Pt catalyst and the proton conductivity in the electrode are enhanced due to the nanofiber structure. Addition of 5 wt % polytetrafluoroethylene (PTFE) and the high porosity of the electrospun electrode optimizes water management and improves cell performance.
      PubDate: 2017-03-23T08:40:27.568382-05:
      DOI: 10.1002/ente.201600734
       
  • Reversible Tuning of Visible Wavelength Surface Lattice Resonances in
           Self-Assembled Hybrid Monolayers
    • Authors: Kirsten Volk; Joseph P. S. Fitzgerald, Pia Ruckdeschel, Markus Retsch, Tobias A. F. König, Matthias Karg
      Abstract: Periodic arrays of plasmonic nanostructures can support surface lattice resonances emerging from coupling between localized and diffractive modes. This allows the confinement of light at the nanometer scale with significantly increased resonance lifetimes as compared to those of purely localized modes. Here, we demonstrate that self-assembly of plasmonic hybrid nanoparticles allows the simple and fast fabrication of periodic plasmonic monolayers featuring macroscopic dimensions and easily controllable lattice spacings. Electromagnetic coupling between diffractive and localized modes is significantly enhanced when the arrays are embedded in a homogeneous refractive index environment. This is realized through spin-coating of a polymer film on top of the colloidal monolayer. Narrow surface lattice resonances are detected by far-field extinction spectroscopy while optical microscopy reveals a homogeneous coupling strength on cm-sized substrates. The surface lattice resonance position is changed by manipulation of the refractive index of the polymer film through the immersion into different organic solvents. Capitalizing on the thermoresponsive behavior of the polymer film we modulate the surface lattice resonance by temperature in a fully reversible, dynamic manner. The findings demonstrate the potential of colloidal self-assembly as a bottom-up approach for the fabrication of future nanophotonic devices.Dynamically tunable surface lattice resonances in self-assembled particle arrays are demonstrated. Hexagonally ordered monolayers of wet-chemically synthesized hybrid core–shell particles with silver nanoparticle cores enable coupling between plasmonic and diffractive modes. A swellable, temperature-responsive polymer coating allows dynamic and fully reversible modulation of the surface lattice resonance position.
      PubDate: 2017-03-22T09:28:47.780009-05:
      DOI: 10.1002/adom.201600971
       
  • High-Performance Visible-Light-Driven Pt/CdS/Graphene
           Photoelectrocatalysts for Methanol Oxidation
    • Authors: Chunyang Zhai; Jiayue Hu, Mingjuan Sun, Mingshan Zhu
      Abstract: Fuel cells, as a technology for the conversion of chemical energy into electrical energy, have been recognized as a promising sustainable power source. Traditional electrocatalysts, together with optically active semiconductors, have been selected as promising catalysts for the improvement of anodic reactions. Herein, cadmium sulfide (CdS) nanoclusters decorated on reduced graphene oxide (RGO) nanosheets were obtained by using a one-pot solvothermal method and then applied as photoactivated supports for the deposition of Pt nanoparticles. The ternary-composite-modified electrode displayed much higher catalytic properties for methanol oxidation than a binary Pt/CdS electrode. Interestingly, when the as-prepared Pt/CdS/RGO electrode was irradiated with visible light, both the catalytic activity and the stability were improved greatly. The synergistic effect of RGO nanosheets and photoirradiation promoted electrocatalytic performance and stability. Our results provide new insight into the development of highly efficient photoelectrocatalysts for applications in direct methanol fuel cells in the presence of visible-light illumination.The power of three: A synergistic effect of RGO nanosheets and photoirradiation promotes the electrocatalytic performance of methanol oxidation under visible-light irradiation.
      PubDate: 2017-03-22T08:52:51.951112-05:
      DOI: 10.1002/ente.201600637
       
  • High-Performance Visible-Light-Driven Pt/CdS/Graphene
           Photoelectrocatalysts for Methanol Oxidation
    • Authors: Chunyang Zhai; Jiayue Hu, Mingjuan Sun, Mingshan Zhu
      Abstract: Fuel cells, as a technology for the conversion of chemical energy into electrical energy, have been recognized as a promising sustainable power source. Traditional electrocatalysts, together with optically active semiconductors, have been selected as promising catalysts for the improvement of anodic reactions. Herein, cadmium sulfide (CdS) nanoclusters decorated on reduced graphene oxide (RGO) nanosheets were obtained by using a one-pot solvothermal method and then applied as photoactivated supports for the deposition of Pt nanoparticles. The ternary-composite-modified electrode displayed much higher catalytic properties for methanol oxidation than a binary Pt/CdS electrode. Interestingly, when the as-prepared Pt/CdS/RGO electrode was irradiated with visible light, both the catalytic activity and the stability were improved greatly. The synergistic effect of RGO nanosheets and photoirradiation promoted electrocatalytic performance and stability. Our results provide new insight into the development of highly efficient photoelectrocatalysts for applications in direct methanol fuel cells in the presence of visible-light illumination.The power of three: A synergistic effect of RGO nanosheets and photoirradiation promotes the electrocatalytic performance of methanol oxidation under visible-light irradiation.
      PubDate: 2017-03-22T08:52:51.951112-05:
      DOI: 10.1002/ente.201600637
       
  • Serpentinite Carbonation Process Routes using Ammonium Sulfate and
           Integration in Industry
    • Authors: Ron Zevenhoven; Martin Slotte, Evelina Koivisto, Rickard Erlund
      Abstract: Vast resources of serpenitinite rock available worldwide are capable of binding CO2 amounts that diminish the capacity of methods based on geological storage of CO2. R&D has been ongoing in Finland for many years on developing large-scale application of process routes for serpentinite carbonation. Several routes have been assessed in the laboratory, in all cases using ammonium salts to extract magnesium from rock followed by carbonation either in a gas/solid reactor at elevated temperatures and pressures or in an aqueous solution at ambient conditions. The choice for either route is motivated by the CO2-producing source, (waste) heat availability, the magnesium (hydro-)carbonate product aimed at, and a preference for energy efficiency or simplicity. Rocks from several locations have been analysed. A special issue is the recovery of the ammonium flux salt, typically from an aqueous solution. As for application, several industry sectors are considered, such as a (natural gas fired) power plant, a lime kiln, or iron- and steelmaking, applying mineral carbonation (MC) to blast furnace top gas. The analysis includes life cycle assessment (LCA). Finally, the use of magnesium (hydro-)carbonates for heat storage is addressed.Several routes allow for large-scale CO2 mineralization of serpentinites by using recoverable and inexpensive ammonium salt. Precapture of CO2 is not necessary, whereas energy input requirements may be largely covered by waste heat from the CO2-generating process. Valuable (hydrated) magnesium carbonate material is obtained.
      PubDate: 2017-03-22T07:32:15.961824-05:
      DOI: 10.1002/ente.201600702
       
  • Serpentinite Carbonation Process Routes using Ammonium Sulfate and
           Integration in Industry
    • Authors: Ron Zevenhoven; Martin Slotte, Evelina Koivisto, Rickard Erlund
      Abstract: Vast resources of serpenitinite rock available worldwide are capable of binding CO2 amounts that diminish the capacity of methods based on geological storage of CO2. R&D has been ongoing in Finland for many years on developing large-scale application of process routes for serpentinite carbonation. Several routes have been assessed in the laboratory, in all cases using ammonium salts to extract magnesium from rock followed by carbonation either in a gas/solid reactor at elevated temperatures and pressures or in an aqueous solution at ambient conditions. The choice for either route is motivated by the CO2-producing source, (waste) heat availability, the magnesium (hydro-)carbonate product aimed at, and a preference for energy efficiency or simplicity. Rocks from several locations have been analysed. A special issue is the recovery of the ammonium flux salt, typically from an aqueous solution. As for application, several industry sectors are considered, such as a (natural gas fired) power plant, a lime kiln, or iron- and steelmaking, applying mineral carbonation (MC) to blast furnace top gas. The analysis includes life cycle assessment (LCA). Finally, the use of magnesium (hydro-)carbonates for heat storage is addressed.Several routes allow for large-scale CO2 mineralization of serpentinites by using recoverable and inexpensive ammonium salt. Precapture of CO2 is not necessary, whereas energy input requirements may be largely covered by waste heat from the CO2-generating process. Valuable (hydrated) magnesium carbonate material is obtained.
      PubDate: 2017-03-22T07:32:15.961824-05:
      DOI: 10.1002/ente.201600702
       
  • Photocharge-Enhanced Capacitive Response of a Supercapacitor
    • Authors: Buddha Deka Boruah; Abha Misra
      Abstract: A radiation-sensitive, binder-free, solid-state supercapacitor (SC) has been fabricated based on spinel nickel cobaltite (NiCo2O4)/zinc oxide nanorods (ZnO NRs) as the electrode material. The enhanced surface area of the electrochemical electrode not only provides a noteworthy enhancement in electrochemical activity, but also the generated photoinduced excitons significantly contribute to achieving outstanding electrode conductivity. This finding reveals that the generated photocharges during UV irradiation participate largely in converting radiation energy into electrochemical energy through redox reactions that allow the specific capacitance to double when compared to an absence of UV radiation. Moreover, the novel SC demonstrates an outstanding cyclic stability of 98.5 and 97 % capacitance retention after 2000 cycles of charge–discharge in the absence and presence of UV irradiation, respectively. Thus, this study opens up an avenue for the direct utilization of radiation-sensitive nanomaterials for electrochemical energy storage and demonstrates a strong potential for the fabrication of advanced SCs.UV-based supercapacitor: A binder-free, radiation sensitive, solid-state supercapacitor based on a NiCo2O4/ZnO nanorod electrode material is described. It displays excellent sensitivity towards UV radiation that induces an excellent enhancement in capacitive response.
      PubDate: 2017-03-22T07:32:14.094781-05:
      DOI: 10.1002/ente.201600661
       
  • Photocharge-Enhanced Capacitive Response of a Supercapacitor
    • Authors: Buddha Deka Boruah; Abha Misra
      Abstract: A radiation-sensitive, binder-free, solid-state supercapacitor (SC) has been fabricated based on spinel nickel cobaltite (NiCo2O4)/zinc oxide nanorods (ZnO NRs) as the electrode material. The enhanced surface area of the electrochemical electrode not only provides a noteworthy enhancement in electrochemical activity, but also the generated photoinduced excitons significantly contribute to achieving outstanding electrode conductivity. This finding reveals that the generated photocharges during UV irradiation participate largely in converting radiation energy into electrochemical energy through redox reactions that allow the specific capacitance to double when compared to an absence of UV radiation. Moreover, the novel SC demonstrates an outstanding cyclic stability of 98.5 and 97 % capacitance retention after 2000 cycles of charge–discharge in the absence and presence of UV irradiation, respectively. Thus, this study opens up an avenue for the direct utilization of radiation-sensitive nanomaterials for electrochemical energy storage and demonstrates a strong potential for the fabrication of advanced SCs.UV-based supercapacitor: A binder-free, radiation sensitive, solid-state supercapacitor based on a NiCo2O4/ZnO nanorod electrode material is described. It displays excellent sensitivity towards UV radiation that induces an excellent enhancement in capacitive response.
      PubDate: 2017-03-22T07:32:14.094781-05:
      DOI: 10.1002/ente.201600661
       
  • Processing–Structure–Property Relationships for Lignin-Based
           Carbonaceous Materials Used in Energy-Storage Applications
    • Authors: Valerie García-Negrón; Nathan D. Phillip, Jianlin Li, Claus Daniel, David Wood, David J. Keffer, Orlando Rios, David P. Harper
      Abstract: Lignin, an abundant organic polymer and a byproduct of pulp and biofuel production, has potential applications owing to its high carbon content and aromatic structure. Processing–structure relationships are difficult to predict because of the heterogeneity of lignin. This work discusses the roles of unit operations in the carbonization process of softwood lignin, and their resulting impacts on the material structure and electrochemical properties in application as the anode in lithium-ion cells. The processing variables include the lignin source, temperature, and duration of thermal stabilization, pyrolysis, and reduction. Materials are characterized at the atomic and microscales. High-temperature carbonization, at 2000 °C, produces larger graphitic domains than at 1050 °C, but results in a reduced capacity. Coulombic efficiencies over 98 % are achieved for extended galvanostatic cycling. Consequently, a properly designed carbonization process for lignin is well suited for the generation of low-cost, high-efficiency electrodes.Lignin for electrodes: The roles of unit operations, stabilization, pyrolysis, reduction, and milling on the performance of carbonized kraft softwood lignin anodes in lithium–carbon coin cells are examined. Batteries with small graphitic domains exhibit capacities in the range 300–400 mAh g−1 with Coulombic efficiencies of over 98 % for most cycles. However, batteries with larger graphitic domain sizes exhibit improved current stability.
      PubDate: 2017-03-22T07:32:04.194568-05:
      DOI: 10.1002/ente.201600646
       
  • Processing–Structure–Property Relationships for Lignin-Based
           Carbonaceous Materials Used in Energy-Storage Applications
    • Authors: Valerie García-Negrón; Nathan D. Phillip, Jianlin Li, Claus Daniel, David Wood, David J. Keffer, Orlando Rios, David P. Harper
      Abstract: Lignin, an abundant organic polymer and a byproduct of pulp and biofuel production, has potential applications owing to its high carbon content and aromatic structure. Processing–structure relationships are difficult to predict because of the heterogeneity of lignin. This work discusses the roles of unit operations in the carbonization process of softwood lignin, and their resulting impacts on the material structure and electrochemical properties in application as the anode in lithium-ion cells. The processing variables include the lignin source, temperature, and duration of thermal stabilization, pyrolysis, and reduction. Materials are characterized at the atomic and microscales. High-temperature carbonization, at 2000 °C, produces larger graphitic domains than at 1050 °C, but results in a reduced capacity. Coulombic efficiencies over 98 % are achieved for extended galvanostatic cycling. Consequently, a properly designed carbonization process for lignin is well suited for the generation of low-cost, high-efficiency electrodes.Lignin for electrodes: The roles of unit operations, stabilization, pyrolysis, reduction, and milling on the performance of carbonized kraft softwood lignin anodes in lithium–carbon coin cells are examined. Batteries with small graphitic domains exhibit capacities in the range 300–400 mAh g−1 with Coulombic efficiencies of over 98 % for most cycles. However, batteries with larger graphitic domain sizes exhibit improved current stability.
      PubDate: 2017-03-22T07:32:04.194568-05:
      DOI: 10.1002/ente.201600646
       
  • Carbon-Coated Magnesium Ferrite Nanofibers for Lithium-Ion Battery Anodes
           with Enhanced Cycling Performance
    • Authors: Lei Luo; Dawei Li, Jun Zang, Chen Chen, Jiadeng Zhu, Hui Qiao, Yibing Cai, Keyu Lu, Xiangwu Zhang, Qufu Wei
      Abstract: Carbon-coated magnesium ferrite (MgFe2O4@C) nanofibers were synthesized by electrospinning technology and a subsequent carbonization process using polydopamine as carbon precursor. SEM and TEM observations revealed that N-doped carbon layers with different thicknesses were coated uniformly on the surface of the MgFe2O4 nanofibers. If used as anode materials for lithium–ion batteries (LIBs), MgFe2O4@C nanofibers with a carbon thickness of 7 nm exhibited an excellent cycling performance and rate capability compared with pristine MgFe2O4 and MgFe2O4@C nanofibers with carbon thicknesses of 4 and 15 nm, respectively. These nanofibers delivered high initial discharge and charge capacities of 1383 and 1044 mAh g−1, respectively, with a Coulombic efficiency of 75.5 %. A reversible capacity of 926 mAh g−1 could be obtained after 200 cycles at 0.1 Ag−1. Even at a high rate of 1 A g−1 after 500 cycles, they still maintained a stable capacity of 610 mAh g−1 with a capacity retention of 81.9 %. Therefore, the MgFe2O4@C nanofibers are a potential anode candidate for LIBs.Get your coat: Polydopamine-derived, nitrogen-doped MgFe2O4@C nanofibers with uniform carbon coating layers exhibit a good cycling performance and rate capability.
      PubDate: 2017-03-22T07:27:28.964102-05:
      DOI: 10.1002/ente.201600686
       
  • Carbon-Coated Magnesium Ferrite Nanofibers for Lithium-Ion Battery Anodes
           with Enhanced Cycling Performance
    • Authors: Lei Luo; Dawei Li, Jun Zang, Chen Chen, Jiadeng Zhu, Hui Qiao, Yibing Cai, Keyu Lu, Xiangwu Zhang, Qufu Wei
      Abstract: Carbon-coated magnesium ferrite (MgFe2O4@C) nanofibers were synthesized by electrospinning technology and a subsequent carbonization process using polydopamine as carbon precursor. SEM and TEM observations revealed that N-doped carbon layers with different thicknesses were coated uniformly on the surface of the MgFe2O4 nanofibers. If used as anode materials for lithium–ion batteries (LIBs), MgFe2O4@C nanofibers with a carbon thickness of 7 nm exhibited an excellent cycling performance and rate capability compared with pristine MgFe2O4 and MgFe2O4@C nanofibers with carbon thicknesses of 4 and 15 nm, respectively. These nanofibers delivered high initial discharge and charge capacities of 1383 and 1044 mAh g−1, respectively, with a Coulombic efficiency of 75.5 %. A reversible capacity of 926 mAh g−1 could be obtained after 200 cycles at 0.1 Ag−1. Even at a high rate of 1 A g−1 after 500 cycles, they still maintained a stable capacity of 610 mAh g−1 with a capacity retention of 81.9 %. Therefore, the MgFe2O4@C nanofibers are a potential anode candidate for LIBs.Get your coat: Polydopamine-derived, nitrogen-doped MgFe2O4@C nanofibers with uniform carbon coating layers exhibit a good cycling performance and rate capability.
      PubDate: 2017-03-22T07:27:28.964102-05:
      DOI: 10.1002/ente.201600686
       
  • Preferential Methanation of CO using Halogen-Doped (F, Cl, Br)
           Ceria-Supported Nickel Catalysts
    • Authors: Margarita V. Konishcheva; Dmitriy I. Potemkin, Pavel V. Snytnikov, Vera P. Pakharukova, Vladimir A. Sobyanin
      Abstract: Halogen-doped Ni(F)/CeO2, Ni(Cl)/CeO2, and Ni(Br)/CeO2 catalysts were prepared by treating halogen-free Ni/CeO2 with aqueous solutions of NH4F, NH4Cl, and NH4Br, respectively. It was demonstrated that the halogen dopants had distinct effects on the catalyst properties for the CO preferential methanation using realistic reformate gas: fluorine did not change catalytic activity, chlorine inhibited CO2 methanation activity and provided high selectivity towards CO methanation, and bromine completely inhibited both the CO and CO2 methanation activity.Selectivity tuning: Halogen doping strongly influenced the Ni/CeO2 catalyst properties in the preferential methanation of CO (CO-SMET): fluorine did not change catalytic activity, chlorine inhibited CO2 methanation activity providing high selectivity towards CO methanation, and bromine totally inhibited both CO and CO2 methanation activity. Thus, controllable poisoning with chlorine provides a unique opportunity to improve the CO-SMET performance of Ni/CeO2 catalysts
      PubDate: 2017-03-22T07:27:15.008967-05:
      DOI: 10.1002/ente.201700088
       
  • Preferential Methanation of CO using Halogen-Doped (F, Cl, Br)
           Ceria-Supported Nickel Catalysts
    • Authors: Margarita V. Konishcheva; Dmitriy I. Potemkin, Pavel V. Snytnikov, Vera P. Pakharukova, Vladimir A. Sobyanin
      Abstract: Halogen-doped Ni(F)/CeO2, Ni(Cl)/CeO2, and Ni(Br)/CeO2 catalysts were prepared by treating halogen-free Ni/CeO2 with aqueous solutions of NH4F, NH4Cl, and NH4Br, respectively. It was demonstrated that the halogen dopants had distinct effects on the catalyst properties for the CO preferential methanation using realistic reformate gas: fluorine did not change catalytic activity, chlorine inhibited CO2 methanation activity and provided high selectivity towards CO methanation, and bromine completely inhibited both the CO and CO2 methanation activity.Selectivity tuning: Halogen doping strongly influenced the Ni/CeO2 catalyst properties in the preferential methanation of CO (CO-SMET): fluorine did not change catalytic activity, chlorine inhibited CO2 methanation activity providing high selectivity towards CO methanation, and bromine totally inhibited both CO and CO2 methanation activity. Thus, controllable poisoning with chlorine provides a unique opportunity to improve the CO-SMET performance of Ni/CeO2 catalysts
      PubDate: 2017-03-22T07:27:15.008967-05:
      DOI: 10.1002/ente.201700088
       
  • Carbon Capture and Utilization Update
    • Authors: Ahmed Al-Mamoori; Anirudh Krishnamurthy, Ali A. Rownaghi, Fateme Rezaei
      Abstract: In recent years, carbon capture and utilization (CCU) has been proposed as a potential technological solution to the problems of greenhouse-gas emissions and the ever-growing energy demand. To combat climate change and ocean acidification as a result of anthropogenic CO2 emissions, efforts have already been put forth to capture and sequester CO2 from large point sources, especially power plants; however, the utilization of CO2 as a feedstock to make valuable chemicals, materials, and transportation fuels is potentially more desirable and provides a better and long-term solution than sequestration. The products of CO2 utilization can supplement or replace chemical feedstocks in the fine chemicals, pharmaceutical, and polymer industries. In this review, we first provide an overview of the current status of CO2-capture technologies and their associated challenges and opportunities with respect to efficiency and economy followed by an overview of various carbon-utilization approaches. The current status of combined CO2 capture and utilization, as a novel efficient and cost-effective approach, is also briefly discussed. We summarize the main challenges associated with the design, development, and large-scale deployment of CO2 capture and utilization processes to provide a perspective and roadmap for the development of new technologies and opportunities to accelerate their scale-up in the near future.Catch and release: A short overview of recent advancements in the fields of CO2 capture and utilization is given in this review. More specifically, we summarize the main challenges associated with the design, development, and large-scale deployment of CO2 capture and utilization processes with respect to efficiency and economy to provide a perspective and roadmap for the development of new technologies and opportunities to accelerate their scale-up in the near future.
      PubDate: 2017-03-21T05:06:28.276017-05:
      DOI: 10.1002/ente.201600747
       
  • Carbon Capture and Utilization Update
    • Authors: Ahmed Al-Mamoori; Anirudh Krishnamurthy, Ali A. Rownaghi, Fateme Rezaei
      Abstract: In recent years, carbon capture and utilization (CCU) has been proposed as a potential technological solution to the problems of greenhouse-gas emissions and the ever-growing energy demand. To combat climate change and ocean acidification as a result of anthropogenic CO2 emissions, efforts have already been put forth to capture and sequester CO2 from large point sources, especially power plants; however, the utilization of CO2 as a feedstock to make valuable chemicals, materials, and transportation fuels is potentially more desirable and provides a better and long-term solution than sequestration. The products of CO2 utilization can supplement or replace chemical feedstocks in the fine chemicals, pharmaceutical, and polymer industries. In this review, we first provide an overview of the current status of CO2-capture technologies and their associated challenges and opportunities with respect to efficiency and economy followed by an overview of various carbon-utilization approaches. The current status of combined CO2 capture and utilization, as a novel efficient and cost-effective approach, is also briefly discussed. We summarize the main challenges associated with the design, development, and large-scale deployment of CO2 capture and utilization processes to provide a perspective and roadmap for the development of new technologies and opportunities to accelerate their scale-up in the near future.Catch and release: A short overview of recent advancements in the fields of CO2 capture and utilization is given in this review. More specifically, we summarize the main challenges associated with the design, development, and large-scale deployment of CO2 capture and utilization processes with respect to efficiency and economy to provide a perspective and roadmap for the development of new technologies and opportunities to accelerate their scale-up in the near future.
      PubDate: 2017-03-21T05:06:28.276017-05:
      DOI: 10.1002/ente.201600747
       
  • Alkali Carbonate Molten Salt Coated Calcium Oxide with Highly Improved
           Carbon Dioxide Capture Capacity
    • Authors: Liang Huang; Yu Zhang, Wanlin Gao, Takuya Harada, Qingqing Qin, Qianwen Zheng, T. Alan Hatton, Qiang Wang
      Abstract: CO2 reduction is crucial if the effects of this gas on global warming are to be alleviated. We report for the first time an alkali carbonate molten salt promoted CaO-based CO2 sorbent with CO2 capture performance superior to that of neat CaO. The influences of chemical composition, loading, and melting temperature of the (Li–Na–K)2CO3 molten salts and of the calcination and adsorption temperatures on CO2 capture were evaluated systematically. The microstructural and morphological evolution of the samples during CO2 adsorption was studied by X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy analyses. The (Li–K)2CO3 molten salt coating was found not only to promote CO2 uptake but also to facilitate CO2 desorption from CaO. In particular, at low temperatures of 500 and 600 °C, the CO2 capture capacity increased significantly from 1.19 and 3.26 mmol g−1 to 6.93 and 10.38 mmol g−1, respectively. The melting point of the molten salts was also a crucial factor in the improvement of CO2 uptake. Kinetic studies based on fractal-like models indicated that the rate coefficients for (Li–K)2CO3/CaO were approximately 3.3 to 3.8 times larger than those for neat CaO. The coating of alkali carbonate molten salts is believed to prevent the formation of a rigid CaCO3 layer on the surface of the CaO particles and to provide continuous delivery of CO32− to promote CO2 capture. During the CO2 adsorption/desorption cycling tests, (Li–K)2CO3/CaO resulted in a stable and reversible CO2 uptake of 6.0–6.3 mmol g−1, which is much higher than that of neat CaO (2.0 mmol g−1).How low can you go: A molten salts promoted CaO sorbent is reported for CO2 capture for the first time and shows markedly improved CO2 capture capacity at 400 to 600 °C (especially at low temperatures). This work represents a novel scheme for preventing the sintering of CaO by shifting its operation temperatures to a lower temperature window.
      PubDate: 2017-03-21T05:02:40.919264-05:
      DOI: 10.1002/ente.201600628
       
  • Alkali Carbonate Molten Salt Coated Calcium Oxide with Highly Improved
           Carbon Dioxide Capture Capacity
    • Authors: Liang Huang; Yu Zhang, Wanlin Gao, Takuya Harada, Qingqing Qin, Qianwen Zheng, T. Alan Hatton, Qiang Wang
      Abstract: CO2 reduction is crucial if the effects of this gas on global warming are to be alleviated. We report for the first time an alkali carbonate molten salt promoted CaO-based CO2 sorbent with CO2 capture performance superior to that of neat CaO. The influences of chemical composition, loading, and melting temperature of the (Li–Na–K)2CO3 molten salts and of the calcination and adsorption temperatures on CO2 capture were evaluated systematically. The microstructural and morphological evolution of the samples during CO2 adsorption was studied by X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy analyses. The (Li–K)2CO3 molten salt coating was found not only to promote CO2 uptake but also to facilitate CO2 desorption from CaO. In particular, at low temperatures of 500 and 600 °C, the CO2 capture capacity increased significantly from 1.19 and 3.26 mmol g−1 to 6.93 and 10.38 mmol g−1, respectively. The melting point of the molten salts was also a crucial factor in the improvement of CO2 uptake. Kinetic studies based on fractal-like models indicated that the rate coefficients for (Li–K)2CO3/CaO were approximately 3.3 to 3.8 times larger than those for neat CaO. The coating of alkali carbonate molten salts is believed to prevent the formation of a rigid CaCO3 layer on the surface of the CaO particles and to provide continuous delivery of CO32− to promote CO2 capture. During the CO2 adsorption/desorption cycling tests, (Li–K)2CO3/CaO resulted in a stable and reversible CO2 uptake of 6.0–6.3 mmol g−1, which is much higher than that of neat CaO (2.0 mmol g−1).How low can you go: A molten salts promoted CaO sorbent is reported for CO2 capture for the first time and shows markedly improved CO2 capture capacity at 400 to 600 °C (especially at low temperatures). This work represents a novel scheme for preventing the sintering of CaO by shifting its operation temperatures to a lower temperature window.
      PubDate: 2017-03-21T05:02:40.919264-05:
      DOI: 10.1002/ente.201600628
       
  • Degradation Mechanism and Lifetime Improvement Strategy for Blue
           Phosphorescent Organic Light-Emitting Diodes
    • Authors: Wook Song; Jun Yeob Lee
      Abstract: Providing adequate lifetimes for organic light-emitting diodes (OLEDs) has been a challenging issue for a long time because of the naturally weak chemical bonds of organic materials that can be damaged during electrical processes that drive light emission. The lifetime of OLEDs has been dramatically extended to the point where commercialization is feasible due to the development of stable materials and device structures that lessen the damage of the organic materials. However, the lifetime of high efficiency OLEDs represented by phosphorescent OLEDs is still short, and this prevents full utilization in red, green and blue colors. The lifetime of the blue phosphorescent OLEDs is particularly short, i.e., less than one tenth of the lifetime of conventional blue fluorescent OLEDs. Therefore, a large increase in the lifetime of the blue phosphorescent OLEDs is essential. In this work, recent results on the degradation mechanism and operational stability of blue phosphorescent OLEDs are reviewed by classifying them into material and device related approaches. In addition, ideal material and device plans to reach the lifetimes required for commercialization in blue phosphorescent OLEDs are proposed.Recent results reporting the degradation mechanism and operational stability of blue phosphorescent OLEDs are reviewed by classifying them into material and device related approaches. In addition, ideal material and device plans to reach the commercialization lifetime level in blue phosphorescent OLEDs are proposed.
      PubDate: 2017-03-21T02:45:32.849867-05:
      DOI: 10.1002/adom.201600901
       
  • Energy-Efficient Heat Storage using Gypsum Board with Fatty Acid Ester as
           Layered Phase Change Material
    • Authors: Seunghwan Wi; Su-Gwang Jeong, Seong Jin Chang, Jongki Lee, Sumin Kim
      Abstract: The thermal performance of phase change materials (PCMs) for energy savings is important in various fields. Fatty acid waxes are types of organic fatty acid ester PCMs made from under-used and renewable feedstocks. However, they possess one major drawback, namely their phase instability in the liquid state. Therefore, to improve stability during phase transitions, a new method of leakage prevention was developed to form the layer. The thermal properties of the layered PCM gypsum boards were analyzed by differential scanning calorimetry (DSC), phase change, enthalpy, and leakage tests. Finally, a dynamic heat transfer analysis of the layered PCM gypsum board was performed for the evaluation of the peak temperature reduction time lag effects of the prepared specimen. The latent heats of palm wax (PW) and beeswax (BW) were 178.1 and 173.6 J g−1 during heating, 159.7 and 140.9 J g−1, during freezing, respectively. Furthermore, the peak temperatures of the three wax-infused layered PCM gypsum board samples were reduced by 4.6, 6.6 and 0.9 °C, respectively, compared with reference gypsum board.Band of gypsum: The thermal properties of gypsum-board layered phase change materials (LCPM) are analyzed by differential scanning calorimetry (DSC), phase change analysis, enthalpy analysis, and leakage tests. A dynamic heat transfer analysis of the LPCM gypsum board is also performed. The LPCM gypsum boards exhibit high heat storage, peak temperature shifting, and time lag effects for maintaining thermal inertia.
      PubDate: 2017-03-20T05:41:03.47826-05:0
      DOI: 10.1002/ente.201600689
       
  • Energy-Efficient Heat Storage using Gypsum Board with Fatty Acid Ester as
           Layered Phase Change Material
    • Authors: Seunghwan Wi; Su-Gwang Jeong, Seong Jin Chang, Jongki Lee, Sumin Kim
      Abstract: The thermal performance of phase change materials (PCMs) for energy savings is important in various fields. Fatty acid waxes are types of organic fatty acid ester PCMs made from under-used and renewable feedstocks. However, they possess one major drawback, namely their phase instability in the liquid state. Therefore, to improve stability during phase transitions, a new method of leakage prevention was developed to form the layer. The thermal properties of the layered PCM gypsum boards were analyzed by differential scanning calorimetry (DSC), phase change, enthalpy, and leakage tests. Finally, a dynamic heat transfer analysis of the layered PCM gypsum board was performed for the evaluation of the peak temperature reduction time lag effects of the prepared specimen. The latent heats of palm wax (PW) and beeswax (BW) were 178.1 and 173.6 J g−1 during heating, 159.7 and 140.9 J g−1, during freezing, respectively. Furthermore, the peak temperatures of the three wax-infused layered PCM gypsum board samples were reduced by 4.6, 6.6 and 0.9 °C, respectively, compared with reference gypsum board.Band of gypsum: The thermal properties of gypsum-board layered phase change materials (LCPM) are analyzed by differential scanning calorimetry (DSC), phase change analysis, enthalpy analysis, and leakage tests. A dynamic heat transfer analysis of the LPCM gypsum board is also performed. The LPCM gypsum boards exhibit high heat storage, peak temperature shifting, and time lag effects for maintaining thermal inertia.
      PubDate: 2017-03-20T05:41:03.47826-05:0
      DOI: 10.1002/ente.201600689
       
  • New Hybrid Materials for Improved Hydrogen Production by the
           Sorption-Enhanced Steam Reforming of Butanol
    • Authors: Karan D. Dewoolkar; Prakash D. Vaidya
      Abstract: Catalytically assisted steam reforming coupled with the selective separation of the produced CO2 is a promising approach for improved H2 production. In this work, we synthesized a new mixture (K-Ni-CaO/HTlc) of two potential sorbents CaO and hydrotalcite (HTlc), the promoter K, and the reforming catalyst Ni. This hybrid material was tested for the sorption-enhanced steam reforming of butanol (SESRB) and its performance was compared to that of two unpromoted hybrid materials Ni-CaO/HTlc and Ni-CaO/Al2O3. All these hybrid materials were able to produce high-purity H2. In particular, K-Ni-CaO/HTlc exhibited the highest H2 concentration (98.7 mol %) and adsorption capacity (12.8 mol CO2 kgsorbent−1) at 823 K. The cyclic durability was tested for 25 cycles, and K-Ni-CaO/HTlc was stable for up to 21 cycles. Conversely, Ni-CaO/HTlc and Ni-CaO/Al2O3 remained stable for 15 and 11 cycles only. The addition of K as a promoter was justified by the improved H2 production and multicycle resilience. Finally, a plausible reaction mechanism for SESRB that predominates over the investigated hybrid materials was suggested.Multifunctional hybrid materials: High-purity H2 with in situ CO2 adsorption is produced over new hybrid materials (catalyst+sorbent). Multicycle durability with low CO and CO2 concentrations lead to sustainable and economical H2 production.
      PubDate: 2017-03-16T09:45:57.545762-05:
      DOI: 10.1002/ente.201600645
       
  • New Hybrid Materials for Improved Hydrogen Production by the
           Sorption-Enhanced Steam Reforming of Butanol
    • Authors: Karan D. Dewoolkar; Prakash D. Vaidya
      Abstract: Catalytically assisted steam reforming coupled with the selective separation of the produced CO2 is a promising approach for improved H2 production. In this work, we synthesized a new mixture (K-Ni-CaO/HTlc) of two potential sorbents CaO and hydrotalcite (HTlc), the promoter K, and the reforming catalyst Ni. This hybrid material was tested for the sorption-enhanced steam reforming of butanol (SESRB) and its performance was compared to that of two unpromoted hybrid materials Ni-CaO/HTlc and Ni-CaO/Al2O3. All these hybrid materials were able to produce high-purity H2. In particular, K-Ni-CaO/HTlc exhibited the highest H2 concentration (98.7 mol %) and adsorption capacity (12.8 mol CO2 kgsorbent−1) at 823 K. The cyclic durability was tested for 25 cycles, and K-Ni-CaO/HTlc was stable for up to 21 cycles. Conversely, Ni-CaO/HTlc and Ni-CaO/Al2O3 remained stable for 15 and 11 cycles only. The addition of K as a promoter was justified by the improved H2 production and multicycle resilience. Finally, a plausible reaction mechanism for SESRB that predominates over the investigated hybrid materials was suggested.Multifunctional hybrid materials: High-purity H2 with in situ CO2 adsorption is produced over new hybrid materials (catalyst+sorbent). Multicycle durability with low CO and CO2 concentrations lead to sustainable and economical H2 production.
      PubDate: 2017-03-16T09:45:57.545762-05:
      DOI: 10.1002/ente.201600645
       
  • Multiscale Reactor Network Simulation of an Entrained Flow Biomass
           Gasifier: Model Description and Validation
    • Authors: Jim Andersson; Kentaro Umeki, Erik Furusjö, Kawnish Kirtania, Fredrik Weiland
      Abstract: This paper describes the development of a multiscale equivalent reactor network model for pressurized entrained flow biomass gasification to quantify the effect of operational parameters on the gasification process, including carbon conversion, cold gas efficiency, and syngas methane content. The model, implemented in the commercial software Aspen Plus, includes chemical kinetics as well as heat and mass transfer. Characteristic aspects of the model are the multiscale effect caused by the combination of transport phenomena at particle scale during heating, pyrolysis, and char burnout, as well as the effect of macroscopic gas flow, including gas recirculation. A validation using experimental data from a pilot-scale process shows that the model can provide accurate estimations of carbon conversion, concentrations of main syngas components, and cold gas efficiency over a wide range of oxygen-to-biomass ratios and reactor loads. The syngas methane content was most difficult to estimate accurately owing to the unavailability of accurate kinetic parameters for steam methane reforming.Predictive gasification model: A multiscale equivalent reactor network model has good predictive ability for pressurized entrained flow biomass gasification. Validation using pilot-scale experiments shows that the model can quantify the effects of operational parameters on syngas composition, carbon conversion, and cold gas efficiency.
      PubDate: 2017-03-16T09:40:47.499485-05:
      DOI: 10.1002/ente.201600760
       
  • Multiscale Reactor Network Simulation of an Entrained Flow Biomass
           Gasifier: Model Description and Validation
    • Authors: Jim Andersson; Kentaro Umeki, Erik Furusjö, Kawnish Kirtania, Fredrik Weiland
      Abstract: This paper describes the development of a multiscale equivalent reactor network model for pressurized entrained flow biomass gasification to quantify the effect of operational parameters on the gasification process, including carbon conversion, cold gas efficiency, and syngas methane content. The model, implemented in the commercial software Aspen Plus, includes chemical kinetics as well as heat and mass transfer. Characteristic aspects of the model are the multiscale effect caused by the combination of transport phenomena at particle scale during heating, pyrolysis, and char burnout, as well as the effect of macroscopic gas flow, including gas recirculation. A validation using experimental data from a pilot-scale process shows that the model can provide accurate estimations of carbon conversion, concentrations of main syngas components, and cold gas efficiency over a wide range of oxygen-to-biomass ratios and reactor loads. The syngas methane content was most difficult to estimate accurately owing to the unavailability of accurate kinetic parameters for steam methane reforming.Predictive gasification model: A multiscale equivalent reactor network model has good predictive ability for pressurized entrained flow biomass gasification. Validation using pilot-scale experiments shows that the model can quantify the effects of operational parameters on syngas composition, carbon conversion, and cold gas efficiency.
      PubDate: 2017-03-16T09:40:47.499485-05:
      DOI: 10.1002/ente.201600760
       
  • Aperiodic Metal-Dielectric Multilayers as Highly Efficient Sunlight
           Reflectors
    • Authors: Alberto Jiménez-Solano; Miguel Anaya, Mauricio E. Calvo, Mercedes Alcon-Camas, Carlos Alcañiz, Elena Guillén, Noelia Martínez, Manuel Gallas, Thomas Preussner, Ramón Escobar-Galindo, Hernán Míguez
      Abstract: The optimum reflection of the solar spectrum at well-defined incident directions as well as its durability in time are, both, fundamental requirements of the optics of thermosolar and photovoltaic energy conversion systems. The stringent high performance needed for these applications implies that, almost exclusively, second face mirrors based on silver are employed for this purpose. Herein, the possibility to develop solar mirrors using other metals, such as copper and aluminum, is theoretically and experimentally analyzed. It is found that reflectors based on these inexpensive metals are capable of reflecting the full solar spectrum with efficiencies comparable to that of silver-based reflectors. The designs herein proposed are based on aperiodic metal-dielectric multilayers whose optimized configuration is chosen employing a code based on a genetic algorithm that allows selecting the best one among 108 tested reflectors. The use of metals with wider spectral absorption bands is compensated by the use of multilayered designs in which metal absorption is almost suppressed, as the analysis of the electric field intensity distribution demonstrates. The feasibility of the proposed mirrors is demonstrated by their actual fabrication by large area deposition techniques amenable for mass production.Aperiodic metal-dielectric multilayers are optimized to maximize the reflection of the whole solar spectrum; designs based on copper, showing a performance as solar mirrors that matches that of standard silver-based reflectors, are manufactured, characterized, and tested under field conditions demonstrating excellent stability after a year.
      PubDate: 2017-03-15T08:25:32.335099-05:
      DOI: 10.1002/adom.201600833
       
  • Dibenzoindigo: A Nature-Inspired Biocompatible Semiconductor Material for
           Sustainable Organic Electronics
    • Authors: Lidiya I. Leshanskaya; Irina V. Klimovich, Dolgor D. Dashitsyrenova, Lyubov A. Frolova, Elizaveta S. Ershova, Vasilina A. Sergeeva, Vyacheslav Yu. Tabakov, Svetlana V. Kostyuk, Konstantin A. Lyssenko, Pavel A. Troshin
      Abstract: Synthesis and systematic investigation of dibenzoindigo, a derivative of the natural colorant indigo with an extended π-electron conjugated system, is presented. This material shows comparable hole mobilities in organic field-effect transistors (OFETs) with the benchmark semiconductors such as pentacene and dinaphthothienothiophene. Relatively easy synthesis of dibenzoindigo, low toxicity, and excellent ambient stability in OFETs makes it promising material for designing sustainable and biocompatible organic electronics. Air-stable operation of optical memory elements has been demonstrated using dibenzonindigo as semiconductor and spirooxazine-type photochromic material as a light sensitive component.Dibenzoindigo, a new nature-inspired semiconductor material shows high biocompatibility with human cells as revealed by in vitro assays and demonstrates advanced electrical performance in organic field-effect transistors and optical memory elements on the same level as state-of-the-art organic semiconductors known in the field.
      PubDate: 2017-03-15T08:25:27.304507-05:
      DOI: 10.1002/adom.201601033
       
  • Carbon Dioxide Electroreduction using a Silver–Zinc Alloy
    • Authors: Toru Hatsukade; Kendra P. Kuhl, Etosha R. Cave, David N. Abram, Jeremy T. Feaster, Anna L. Jongerius, Christopher Hahn, Thomas F. Jaramillo
      Abstract: We report on CO2 electroreduction activity and selectivity of a polycrystalline AgZn foil in aqueous bicarbonate electrolyte. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements show that the alloy foil was slightly enriched in zinc both at the surface and in the bulk, with a surface alloy composition of 61.3±5.4 at % zinc and with Ag5Zn8 as the most prominent bulk phase. AgZn is active for CO2 reduction; CO is the main product, likely due to the weak CO binding energy of the surface, with methane and methanol emerging as minor products. Compared to pure silver and pure zinc foils, enhancements in activity and selectivity for methane and methanol are observed. A five-fold increase is observed in the combined partial current densities for methane and methanol at −1.43 V vs. the reversible hydrogen electrode (RHE), representing a four- to six-fold increase in faradaic efficiency. Such enhancements indicate the existence of a synergistic effect between silver and zinc at the surface of the alloy that contributes to the enhanced formation of further reduced products.Multi-metal synergy! High CO2 electroreduction activity and selectivity are reported on a polycrystalline AgZn foil in aqueous bicarbonate electrolyte. Compared to pure Ag and pure Zn foils, enhancements in activity and selectivity for methane and methanol are observed. Such enhancements indicate the existence of a synergistic effect between Ag and Zn at the surface of the alloy that contributes to the enhanced formation of further reduced products.
      PubDate: 2017-03-09T08:50:40.760786-05:
      DOI: 10.1002/ente.201700087
       
  • Carbon Dioxide Electroreduction using a Silver–Zinc Alloy
    • Authors: Toru Hatsukade; Kendra P. Kuhl, Etosha R. Cave, David N. Abram, Jeremy T. Feaster, Anna L. Jongerius, Christopher Hahn, Thomas F. Jaramillo
      Abstract: We report on CO2 electroreduction activity and selectivity of a polycrystalline AgZn foil in aqueous bicarbonate electrolyte. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements show that the alloy foil was slightly enriched in zinc both at the surface and in the bulk, with a surface alloy composition of 61.3±5.4 at % zinc and with Ag5Zn8 as the most prominent bulk phase. AgZn is active for CO2 reduction; CO is the main product, likely due to the weak CO binding energy of the surface, with methane and methanol emerging as minor products. Compared to pure silver and pure zinc foils, enhancements in activity and selectivity for methane and methanol are observed. A five-fold increase is observed in the combined partial current densities for methane and methanol at −1.43 V vs. the reversible hydrogen electrode (RHE), representing a four- to six-fold increase in faradaic efficiency. Such enhancements indicate the existence of a synergistic effect between silver and zinc at the surface of the alloy that contributes to the enhanced formation of further reduced products.Multi-metal synergy! High CO2 electroreduction activity and selectivity are reported on a polycrystalline AgZn foil in aqueous bicarbonate electrolyte. Compared to pure Ag and pure Zn foils, enhancements in activity and selectivity for methane and methanol are observed. Such enhancements indicate the existence of a synergistic effect between Ag and Zn at the surface of the alloy that contributes to the enhanced formation of further reduced products.
      PubDate: 2017-03-09T08:50:40.760786-05:
      DOI: 10.1002/ente.201700087
       
  • Sustainion Imidazolium-Functionalized Polymers for Carbon Dioxide
           Electrolysis
    • Authors: Robert B. Kutz; Qingmei Chen, Hongzhou Yang, Syed D. Sajjad, Zengcai Liu, I. Richard Masel
      Abstract: CO2 electrolysis is a key step in CO2 conversion into fuels and chemicals as a way of mitigating climate change. We report the synthesis and testing of a series of new anion-conductive membranes (tradenamed Sustainion™) for use in CO2 electrolysis. These membranes incorporate the functional character of imidazolium-based ionic liquids as co-catalysts in CO2 reduction into a solid membrane with a styrene backbone. We find that the addition of an imidazolium group onto the styrene side-chains increases the selectivity of the reaction from approximately 25 % to approximately 95 %. The current at 3 V is increased by a factor of 14. So far we have been able to tune these parameters to achieve stable cells that provide current densities higher than 100 mA cm−2 at 3 V cell potential with a CO product selectivity over 98 %. Stable performance was observed for 6 months of continuous operation (>150 000 000 turnovers). These results demonstrate that imidazolium polymers are ideal membranes for CO2 electrolysis.Membrane power: A new anion-exchange polymer called Sustainion is described that acts as a co-catalyst for CO2 reduction. The performance of the polymer is tested under a variety of conditions and compared to the performance of commercially available polymers. We achieve far higher rates and selectivities. Further enhancements are also explored.
      PubDate: 2017-03-09T05:35:32.938857-05:
      DOI: 10.1002/ente.201600636
       
  • Discharge Capacity Estimation for Lithium–Ion Battery Packs with Cells
           in Parallel Connection Based on Current Prediction of In-Pack Cells
    • Authors: Long Cheng; Quan Sun
      Abstract: Discharge capacity estimation for battery packs is one of the most essential issues of battery management systems. Precision of the estimation will affect maintenance policy and reliability estimation of the battery packs. Due to different manufacturing processes and use conditions, the performance of each cell in a battery pack may be significantly different. Such differences mean that a certain amount of capacity is not extracted from the in-pack cells. For lithium-ion battery packs with cells connected in parallel, a method is provided herein to predict the discharge current of the cells. Based on this method, an estimation of the discharge capacity of the pack can be obtained. An experiment is then conducted from which the cell current cannot be measured to validate the applicability of the method. The results show that the proposed method can be used to estimate the discharge capacity of battery packs with high accuracy. This method is significant for the grouping of lithium-ion battery packs, as well as the maintenance and replacement policy of battery packs.Full potential: Discharge capacity estimation for battery packs is an essential issue for battery management systems. Precise estimation affects maintenance policies and reliability estimation of the battery packs. A method is provided to predict the discharge current of cells in lithium-ion battery packs with cells connected in parallel.
      PubDate: 2017-03-08T08:45:33.725794-05:
      DOI: 10.1002/ente.201600549
       
  • Evidence of Optical Circular Dichroism in GaAs-Based Nanowires Partially
           Covered with Gold
    • Authors: Grigore Leahu; Emilija Petronijevic, Alessandro Belardini, Marco Centini, Concita Sibilia, Teemu Hakkarainen, Eero Koivusalo, Marcelo Rizzo Piton, Soile Suomalainen, Mircea Guina
      Abstract: Semiconductor nanostructures hybridized with metals have been known to offer new opportunities in nonlinear optics, plasmonics, lasing, biosensors; among them GaAs-based nanowires (NWs) hybridized with gold can offer new functionalities, as chiral sensing and light manipulation, as well as circular polarization sources. This study investigates GaAs–AlGaAs–GaAs NWs fabricated by self-catalyzed growth on Si substrates, and partially covered with gold, thus inducing the symmetry breaking and a potential chiral response. Three different samples are investigated, each of them with a different morphology, as the length and the overall diameter ranging from 4.6 to 5.19 µm and from 138 up to 165 nm, respectively. The samples are first characterized by measuring the absorption spectra by using a scattering-free photoacoustic (PA) technique. Then, the circular dichroism (CD) is investigated by measuring PA absorption for circularly polarized light under different incident angles at 532 and 980 nm. An efficient CD is found for proper configurations, and results are in good agreement with extrinsic chiral theory predictions and numerical simulations. It is therefore proven that these samples exhibit chiral behavior, and can be further optimized. Moreover, PA technique can be used as an extremely sensitive and efficient technique to characterize their “extrinsic” chirality.GaAs–AlGaAs–GaAs nanowires (NWs) with asymmetric gold covering put in interaction with circularly polarized light mimic a chiral response measured by photoacoustic absorption technique. Bringing together the advantages of good optical properties of vertical NWs and “extrinsic” chiral behavior leads to the new perspectives in control of the light at nanoscale.
      PubDate: 2017-03-07T07:35:56.440165-05:
      DOI: 10.1002/adom.201601063
       
  • Carbon Dioxide Absorption using Solid Sorbents Incorporating Purified
           Components of Tetraethylenepentamine
    • Authors: Ryohei Numaguchi; Firoz A. Chowdhury, Hidetaka Yamada, Katsunori Yogo
      Abstract: Tetraethylenepentamine (TEPA) components are separated by fractional distillation, and the structure of each fraction is established using spectroscopic methods. Then, solid sorbents incorporating these components are prepared, and the capacities and rates of CO2 absorption of the sorbents are evaluated to elucidate how the molecular structure affects the absorption performance.Tetraethylenepentamine (TEPA) components are separated by fractional distillation, and the structure of each fraction is established using spectroscopic methods. Then, solid sorbents incorporating these components are prepared, and the capacities and rates of CO2 absorption of the sorbents are evaluated to elucidate how the molecular structure affects absorption performance.
      PubDate: 2017-03-06T05:25:27.496516-05:
      DOI: 10.1002/ente.201600665
       
  • Very Small Inverted Hysteresis in Vacuum-Deposited Mixed
           Organic–Inorganic Hybrid Perovskite Solar Cells
    • Authors: Enkhtur Erdenebileg; Lauren E. Scholz, Andreas Hofacker, Christian Koerner, Karl Leo
      Abstract: Perovskite solar cells (PSCs) have attracted great interest over the past few years due to their outstanding power conversion efficiencies. However, operational stability still needs to be improved for broad commercial application. A commonly observed phenomenon for PSCs is hysteresis in their current–voltage characteristics, which has been suggested to be related to issues with long-term stability. A thorough understanding of the processes involved in hysteresis may also guide the way to further improving the cells’ efficiencies. We fabricate planar p–i–n organic–inorganic hybrid PSCs using three different organic transport layer architectures by vacuum deposition and measured their hysteresis and long-term stability behavior. Our results show that vacuum-deposited PSCs show much weaker hysteresis than in previous studies, where many types of PSCs were involved. For our devices, we also report an inverted hysteresis, where efficiency is somewhat higher for a voltage sweep from short circuit to forward-bias conditions than for the reverse sweep at lower scan rates, which has not commonly been observed in previous studies of PSCs. Finally, we observe that up to 94 % of the initial power conversion efficiency of the encapsulated devices remained after storage in the dark for two months.Hysteresis behavior: Hysteresis in the J–V curves of perovskite solar cells presents a challenge to their characterization and ultimate application. We highlight that vacuum-fabricated perovskite planar solar cells show nearly negligible hysteresis in J–V curves at different sweep rates. Furthermore, we observe a hysteresis at various sun intensities starting from 0.001 sun to 6 suns, and the result shows that hysteresis is independent of solar intensity for perovskite solar cells.
      PubDate: 2017-03-06T02:10:28.43089-05:0
      DOI: 10.1002/ente.201700002
       
  • Chiral and Luminescent TiO2 Nanoparticles
    • Authors: Olan Cleary; Finn Purcell-Milton, Aurélien Vandekerckhove, Yurii K. Gun'ko
      Abstract: In this work, new chiral and luminescent TiO2 nanomaterials are prepared by a single step nonaqueous synthesis. Using circular dichroism spectroscopy it is shown that TiO2 nanoparticles are optically active with almost identical mirror images of one another in the band-edge region of titanium dioxide. Investigations of the photoluminescence properties reveal a broad shallow trap state emission centered at 440 nm, with a photoluminescence quantum yield of ≈3.5%, which is among the highest reported for TiO2. Electron microscopy reveals the TiO2 nanostructures to be dendritic aggregates measuring 30–50 nm in size composed of smaller nanorods of 3–4 nm in diameter.New chiral and luminescent TiO2 nanomaterials are prepared by a single step nonaqueous synthesis. These luminescent materials are composed of dendritic aggregates of anatase nanorods, which are chiroptically active in the band-edge region of titanium dioxide.
      PubDate: 2017-03-03T14:05:44.253987-05:
      DOI: 10.1002/adom.201601000
       
  • Electrochemical Carbon Dioxide Reduction at Nanostructured Gold, Copper,
           and Alloy Materials
    • Authors: James W. Vickers; Dominic Alfonso, Douglas R. Kauffman
      Abstract: Mitigating carbon dioxide (CO2) emissions is one of today's most important scientific challenges. Electrochemical conversion of CO2 into industrially relevant chemicals is a leading strategy because it would allow sustainable production of commodity chemicals. In this review, we outline the current progress in nanostructuring gold, copper, and alloy catalysts for the electrochemical CO2 reduction reaction. In general, Au catalysts show structure and voltage dependent CO selectivity alongside the H2 evolution reaction. The ability to tune CO to H2 product distributions is appealing for downstream processing into a variety of industrially relevant chemicals. Cu catalysts produce a wider range of products, and current efforts focus on controlling the product distribution by tuning the catalyst size, structure, oxidation state, and crystallographic orientation. Finally, we discuss the emerging field of computational electrocatalysis with emphasis on the computational hydrogen electrode method. The combination of experiment and computation is important because it provides fundamental insight into chemical processes driving catalytic CO2 conversion. Continued work will help to tune catalyst structure and create next-generation materials with high catalytic activity and desirable product selectivity.Nanostructured CO2 conversion: The electrochemical CO2 reduction reaction (CO2RR) is a promising carbon mitigation strategy. Recent synthetic advances allow control over the catalyst size, surface structure, and morphology. This review describes experimental and computational work on nanostructured CO2RR electrocatalysts with an emphasis on identifying structure–property relationships that influence catalytic reaction rates and product selectivity.
      PubDate: 2017-03-03T06:10:33.791272-05:
      DOI: 10.1002/ente.201600580
       
  • Dopant-Free Hole-Transport Material with a Tetraphenylethene Core for
           Efficient Perovskite Solar Cells
    • Authors: Hongwei Zhu; Fei Zhang, Xicheng Liu, Mengna Sun, Jianlei Han, Jing You, Shirong Wang, Yin Xiao, Xianggao Li
      Abstract: A hole-transport material (HTM), 1,1,2,2-tetrakis[4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl]ethene (TTBCPE), was prepared straightforwardly and employed in the fabrication of perovskite solar cells (PSCs). The investigated HTM with tetraphenylethene as the core and tert-butylcarbazole as terminal units was synthesized in two steps from commercially available and cheap raw materials. The devices based on TTBCPE without the use of any dopants and additives exhibited a power conversion efficiency (PCE) of 12.65 %, which is comparable to 14.46 % obtained by using devices based on 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamino)-9,9′-spirobifluorene (p-doped spiro-OMeTAD). Importantly, the device based on TTBCPE showed a higher stability than devices based on doped spiro-OMeTAD if stored under ambient conditions. In this regard, this easily synthesized and dopant-free system paves a new way to develop low-cost HTMs.The hole truth: A dopant-free hole-transport material, 1,1,2,2-tetrakis[4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl]ethene (TTBCPE), is developed for perovskite solar cells, which exhibit a power conversion efficiency (PCE) up to 12.56 %. Importantly, the device based TTBCPE shows a higher stability than the devices based on doped 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamino)-9,9′-spirobifluorene if stored under ambient conditions.
      PubDate: 2017-03-03T05:45:54.055773-05:
      DOI: 10.1002/ente.201600555
       
  • Dopant-Free Hole-Transport Material with a Tetraphenylethene Core for
           Efficient Perovskite Solar Cells
    • Authors: Hongwei Zhu; Fei Zhang, Xicheng Liu, Mengna Sun, Jianlei Han, Jing You, Shirong Wang, Yin Xiao, Xianggao Li
      Abstract: A hole-transport material (HTM), 1,1,2,2-tetrakis[4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl]ethene (TTBCPE), was prepared straightforwardly and employed in the fabrication of perovskite solar cells (PSCs). The investigated HTM with tetraphenylethene as the core and tert-butylcarbazole as terminal units was synthesized in two steps from commercially available and cheap raw materials. The devices based on TTBCPE without the use of any dopants and additives exhibited a power conversion efficiency (PCE) of 12.65 %, which is comparable to 14.46 % obtained by using devices based on 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamino)-9,9′-spirobifluorene (p-doped spiro-OMeTAD). Importantly, the device based on TTBCPE showed a higher stability than devices based on doped spiro-OMeTAD if stored under ambient conditions. In this regard, this easily synthesized and dopant-free system paves a new way to develop low-cost HTMs.The hole truth: A dopant-free hole-transport material, 1,1,2,2-tetrakis[4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl]ethene (TTBCPE), is developed for perovskite solar cells, which exhibit a power conversion efficiency (PCE) up to 12.56 %. Importantly, the device based TTBCPE shows a higher stability than the devices based on doped 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamino)-9,9′-spirobifluorene if stored under ambient conditions.
      PubDate: 2017-03-03T05:45:54.055773-05:
      DOI: 10.1002/ente.201600555
       
  • Benzoic Acid/TEMPO as a Highly Efficient Metal-Free Catalyst System for
           Selective Oxidation of 5-hydroxymethylfurfural into 2, 5-diformylfuran
    • Authors: Jinlong Li; Guangqiang Lv, Boqiong Lu, Yingxiong Wang, Tiansheng Deng, Xianglin Hou, Yongxing Yang
      Abstract: The combination of benzoic acid and 2,2,6,6-teramethylpiperidin-1-oxyl (TEMPO) afforded an efficient catalytic system for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) under certain conditions. The maximum conversion of 86.7 % for HMF was obtained with a nearly 77.8 % DFF yield at 1 mmol benzoic acid and 0.4 MPa oxygen pressure in acetonitrile. The aerobic oxidation ability of HMF into DFF depended on the electron density of the organic acid skeletal structure with the carboxyl group. Meanwhile, the catalyst system of benzoic acid/TEMPO also exhibited good performance for aerobic oxidation of other alcohols. Based on experimental results, we propose that the benzoic acid acted as the primary catalyst and TEMPO was the key co-catalyst, oxidized into oxoammonium cation through electron transport and then regenerated by a superoxide radical during the reaction.Metal-free catalysis: The combination of benzoic acid and 2,2,6,6-teramethylpiperidin-1-oxyl (TEMPO) affords an efficient catalytic system for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) under certain conditions. Based on experimental results, we propose that the benzoic acid acts as the primary catalyst and TEMPO is the key co-catalyst, oxidized into oxoammonium cation through electron transport and then regenerated by a superoxide radical during the reaction.
      PubDate: 2017-03-03T05:41:25.305472-05:
      DOI: 10.1002/ente.201600715
       
  • Benzoic Acid/TEMPO as a Highly Efficient Metal-Free Catalyst System for
           Selective Oxidation of 5-hydroxymethylfurfural into 2, 5-diformylfuran
    • Authors: Jinlong Li; Guangqiang Lv, Boqiong Lu, Yingxiong Wang, Tiansheng Deng, Xianglin Hou, Yongxing Yang
      Abstract: The combination of benzoic acid and 2,2,6,6-teramethylpiperidin-1-oxyl (TEMPO) afforded an efficient catalytic system for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) under certain conditions. The maximum conversion of 86.7 % for HMF was obtained with a nearly 77.8 % DFF yield at 1 mmol benzoic acid and 0.4 MPa oxygen pressure in acetonitrile. The aerobic oxidation ability of HMF into DFF depended on the electron density of the organic acid skeletal structure with the carboxyl group. Meanwhile, the catalyst system of benzoic acid/TEMPO also exhibited good performance for aerobic oxidation of other alcohols. Based on experimental results, we propose that the benzoic acid acted as the primary catalyst and TEMPO was the key co-catalyst, oxidized into oxoammonium cation through electron transport and then regenerated by a superoxide radical during the reaction.Metal-free catalysis: The combination of benzoic acid and 2,2,6,6-teramethylpiperidin-1-oxyl (TEMPO) affords an efficient catalytic system for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) under certain conditions. Based on experimental results, we propose that the benzoic acid acts as the primary catalyst and TEMPO is the key co-catalyst, oxidized into oxoammonium cation through electron transport and then regenerated by a superoxide radical during the reaction.
      PubDate: 2017-03-03T05:41:25.305472-05:
      DOI: 10.1002/ente.201600715
       
  • Preparation of Different Nickel–Iron/Titania–Alumina Catalysts for
           Hydrogen/Carbon Monoxide Methanation under Atmospheric Pressure
    • Authors: Chongbo Cheng; Chunfei Wu, Dekui Shen
      Abstract: Bimetallic Ni–Fe/TiO2–Al2O3 catalysts were prepared by using the titania–alumina composite as a support, which was synthesized through three different methods (precipitation, co-precipitation, and sol–gel). The synthesized catalysts were characterized by X-ray diffraction, temperature-programmed reduction, and transmission electron microscopy. The catalytic performance of the catalysts for the methanation of syngas was studied under atmospheric pressure. Ni and Fe species were found to be highly dispersed on the TiO2–Al2O3 composite prepared by the sol–gel method, which led to good catalytic performance for CO conversion (≈96.7 %) and methane selectivity (≈94.7 %) at lower temperatures. In addition, less amorphous carbon was deposited on the used Ni–Fe/TiO2–Al2O3 catalyst prepared by the sol–gel method. This was ascribed to the evidenced core-in-shell structures (TiO2 shell with Al2O3 core) of the TiO2–Al2O3 composite prepared by the sol–gel method, which led to prominent stability of the catalyst (≈30 h). The results give an applicable guide for the highly efficient methanation of syngas under atmospheric pressure.In uniform: Core-in-shell structures in the TiO2–Al2O3 composite prepared by the sol–gel method are evidenced by TEM, which unveils its prominent stability to be a support for a catalyst. The Ni-Fe/TiO2-Al2O3 catalyst with the support prepared by the sol–gel method shows excellent catalytic performance (up to 100 % CO conversion), which is attributed to the uniform pore-size distribution and better dispersion of Ni–Fe.
      PubDate: 2017-03-03T05:35:31.586984-05:
      DOI: 10.1002/ente.201600514
       
  • Preparation of Different Nickel–Iron/Titania–Alumina Catalysts for
           Hydrogen/Carbon Monoxide Methanation under Atmospheric Pressure
    • Authors: Chongbo Cheng; Chunfei Wu, Dekui Shen
      Abstract: Bimetallic Ni–Fe/TiO2–Al2O3 catalysts were prepared by using the titania–alumina composite as a support, which was synthesized through three different methods (precipitation, co-precipitation, and sol–gel). The synthesized catalysts were characterized by X-ray diffraction, temperature-programmed reduction, and transmission electron microscopy. The catalytic performance of the catalysts for the methanation of syngas was studied under atmospheric pressure. Ni and Fe species were found to be highly dispersed on the TiO2–Al2O3 composite prepared by the sol–gel method, which led to good catalytic performance for CO conversion (≈96.7 %) and methane selectivity (≈94.7 %) at lower temperatures. In addition, less amorphous carbon was deposited on the used Ni–Fe/TiO2–Al2O3 catalyst prepared by the sol–gel method. This was ascribed to the evidenced core-in-shell structures (TiO2 shell with Al2O3 core) of the TiO2–Al2O3 composite prepared by the sol–gel method, which led to prominent stability of the catalyst (≈30 h). The results give an applicable guide for the highly efficient methanation of syngas under atmospheric pressure.In uniform: Core-in-shell structures in the TiO2–Al2O3 composite prepared by the sol–gel method are evidenced by TEM, which unveils its prominent stability to be a support for a catalyst. The Ni-Fe/TiO2-Al2O3 catalyst with the support prepared by the sol–gel method shows excellent catalytic performance (up to 100 % CO conversion), which is attributed to the uniform pore-size distribution and better dispersion of Ni–Fe.
      PubDate: 2017-03-03T05:35:31.586984-05:
      DOI: 10.1002/ente.201600514
       
  • Broadband Hot Electron Collection for Solar Water Splitting with Plasmonic
           Titanium Nitride
    • Authors: Alberto Naldoni; Urcan Guler, Zhuoxian Wang, Marcello Marelli, Francesco Malara, Xiangeng Meng, Lucas V. Besteiro, Alexander O. Govorov, Alexander V. Kildishev, Alexandra Boltasseva, Vladimir M. Shalaev
      Abstract: The use of hot electrons generated from the decay of surface plasmons is a novel concept that promises to increase the conversion yield in solar energy technologies. Titanium nitride (TiN) is an emerging plasmonic material that offers compatibility with complementary metal-oxide-semiconductor (CMOS) technology, corrosion resistance, as well as mechanical strength and durability, thus outperforming noble metals in terms of cost, mechanical, chemical, and thermal stability. Here, it is shown that plasmonic TiN can inject into TiO2 twice as much hot electrons as Au nanoparticles. TiO2 nanowires decorated with TiN nanoparticles show higher photocurrent enhancement than decorated with Au nanoparticles for photo-electrochemical water splitting. Experimental and theoretical evidence highlight the superior performance of TiN in hot carrier collection due to several factors. First, TiN nanoparticles provide broadband absorption efficiency over the wavelength range 500–1200 nm combined with high field enhancement due to its natural cubic morphology. Second, TiN forms an Ohmic junction with TiO2, thus enabling efficient electron collection compared to Au nanoparticles. Since TiN nanoparticles have strong plasmon resonances in the red, the entire solar spectrum is covered when complemented with Au nanocrystals. These findings show that transition metal nitrides enable plasmonic devices with enhanced performance for solar energy conversion.Plasmonic titanium nitride (TiN) provides two times larger generation of over-barrier hot electrons than Au nanoparticles due to a broadband absorption and improved electrical compatibility at the TiN–TiO2 interface. TiN-nanoparticle-decorated TiO2 nanowires enhance the photo-electrochemical water splitting activity compared to Au nanoparticles. This discovery enables the use of plasmonic nitrides in solar energy conversion.
      PubDate: 2017-03-01T08:25:39.989904-05:
      DOI: 10.1002/adom.201601031
       
  • One-Step Process to Remove Spent Sulfidic Caustics and Assemble Advanced
           Sulfur Cathodes Synchronously for Lithium–Sulfur Batteries
    • Authors: Wenlong Huang; Zhongqiang Shan, Qiwei Tang, Xia Li, Fangning Yang, Yun Wang, Jianhua Tian
      Abstract: Spent sulfidic caustics (SSC) from caustic desulfurization are toxic hazards to the environment and humans. A new one-step process is proposed firstly to decrease the concentration of SSC and to assemble a high-performance sulfur cathode synchronously by electrolyzing a simulating solution with flexible carbon felt (CF) at 15 mA cm−2. The CF that electrolyzed for 8 hours with a sulfur content of 36.6 wt % or 5.63 mgsulfur cm−2 stands out from three S/CF composites in terms of areal capacity and cycling stability. XRD, TEM, thermogravimetric analysis, and Raman spectroscopy were then used to characterize the materials. Values of 4.03 mA h cm−2 over 150 cycles at 0.2 C and 2.34 mA h cm−2 after 90 cycles at 0.5 C can be attributed to an appropriate ratio of the external/inner sulfur content. The beneficial results prove the feasibility of an innovative mode of “pollutant disposal with synchronous application”, which integrates environmental management with the development of storage energy materials efficiently and eliminates the tedious individual disposal of pollutants and preparation of slurry-derived sulfur cathodes.Turn stone into gold: It is of great significance to recycle spent sulfidic caustic (SSC) solution to reduce environmental pollution and gain economic benefits. A new one-step process is proposed as a proof-of-concept solution to remove SSC continuously and assemble a sulfur/carbon composite, which is applicable for use as an advanced cathode in lithium sulfur batteries directly.
      PubDate: 2017-03-01T02:55:43.596863-05:
      DOI: 10.1002/ente.201600611
       
  • One-Step Process to Remove Spent Sulfidic Caustics and Assemble Advanced
           Sulfur Cathodes Synchronously for Lithium–Sulfur Batteries
    • Authors: Wenlong Huang; Zhongqiang Shan, Qiwei Tang, Xia Li, Fangning Yang, Yun Wang, Jianhua Tian
      Abstract: Spent sulfidic caustics (SSC) from caustic desulfurization are toxic hazards to the environment and humans. A new one-step process is proposed firstly to decrease the concentration of SSC and to assemble a high-performance sulfur cathode synchronously by electrolyzing a simulating solution with flexible carbon felt (CF) at 15 mA cm−2. The CF that electrolyzed for 8 hours with a sulfur content of 36.6 wt % or 5.63 mgsulfur cm−2 stands out from three S/CF composites in terms of areal capacity and cycling stability. XRD, TEM, thermogravimetric analysis, and Raman spectroscopy were then used to characterize the materials. Values of 4.03 mA h cm−2 over 150 cycles at 0.2 C and 2.34 mA h cm−2 after 90 cycles at 0.5 C can be attributed to an appropriate ratio of the external/inner sulfur content. The beneficial results prove the feasibility of an innovative mode of “pollutant disposal with synchronous application”, which integrates environmental management with the development of storage energy materials efficiently and eliminates the tedious individual disposal of pollutants and preparation of slurry-derived sulfur cathodes.Turn stone into gold: It is of great significance to recycle spent sulfidic caustic (SSC) solution to reduce environmental pollution and gain economic benefits. A new one-step process is proposed as a proof-of-concept solution to remove SSC continuously and assemble a sulfur/carbon composite, which is applicable for use as an advanced cathode in lithium sulfur batteries directly.
      PubDate: 2017-03-01T02:55:43.596863-05:
      DOI: 10.1002/ente.201600611
       
  • Probing Local Potentials inside Metallic Nanopores with SERS and Bipolar
           Electrochemistry
    • Authors: Yi Li; Chang Chen, Kherim Willems, Sarp Kerman, Liesbet Lagae, Guido Groeseneken, Tim Stakenborg, Pol Van Dorpe
      Abstract: It is essential to understand the local potential distribution of solid-state nanopores in nanofluidic systems. However, applying gate voltage or adding external electrical probes tends to disturb the electric field and/or flow patterns. To solve this problem, an approach is described to monitor the local potential using electrochemical surface enhanced Raman spectroscopy (EC-SERS) in two types of nanocavity pores: doubled-sided gold nanopores (MM nanopores) and single-sided gold nanopores with a dielectric passivation layer on the backside (MD nanopores). Numerical simulations predict an electrical polarization reversal in the two nanopore geometries. Consequently, the redox SERS changes of Nile Blue A on the two gold nanopores are found to be reversed, which is consistent with the variation of polarizations. The driving voltage of metallic nanopore devices is about an order of magnitude lower than that of microfluidic bipolar devices. Our method will not only prove valuable for the design of metallic nanopores, but also will find applications in the measurement of contactless metallized nanofluidic devices.An approach to monitor the local potential is demonstrated using bipolar electrochemical surface-enhanced Raman spectroscopy (SERS). The redox SERS changes of Nile Blue A on two types of gold nanopores are found to be reversed, which is confirmed by numerical simulations. The driving voltage of metallic nanopores is about an order of magnitude lower than that of microfluidic bipolar devices.
      PubDate: 2017-02-24T09:00:45.005908-05:
      DOI: 10.1002/adom.201600907
       
  • Solar Air Heating and Ventilation in Buildings: A Key Component in the
           Forthcoming Renewable Energy Mix
    • Authors: Rosaria Ciriminna; Francesco Meneguzzo, Mario Pecoraino, Mario Pagliaro
      Abstract: The achievements of the last two decades in using solar energy for naturally ventilating and heating buildings of any size and scope across the world are remarkable, though comprising a niche market and being generally poorly known to this point. Air quality, thermal and hygrometric comfort, and reduced energy costs are some of the benefits provided by solar ventilated spaces. We identify the remaining hurdles to be addressed prior to forthcoming widespread adoption of this technology in the building environment across the world, well beyond the cold-climate countries.Solar ventilation: The use of solar energy for naturally ventilating and heating buildings of any size and scope across the world is an underutilized technology. Air quality, thermal and hygrometric comfort, and reduced energy costs are some of the benefits enjoyed by users of solar air heating. We identify the remaining hurdles to be addressed prior to widespread adoption of this technology in the built environment across the world.
      PubDate: 2017-02-22T08:57:02.547155-05:
      DOI: 10.1002/ente.201600758
       
  • Solar Air Heating and Ventilation in Buildings: A Key Component in the
           Forthcoming Renewable Energy Mix
    • Authors: Rosaria Ciriminna; Francesco Meneguzzo, Mario Pecoraino, Mario Pagliaro
      Abstract: The achievements of the last two decades in using solar energy for naturally ventilating and heating buildings of any size and scope across the world are remarkable, though comprising a niche market and being generally poorly known to this point. Air quality, thermal and hygrometric comfort, and reduced energy costs are some of the benefits provided by solar ventilated spaces. We identify the remaining hurdles to be addressed prior to forthcoming widespread adoption of this technology in the building environment across the world, well beyond the cold-climate countries.Solar ventilation: The use of solar energy for naturally ventilating and heating buildings of any size and scope across the world is an underutilized technology. Air quality, thermal and hygrometric comfort, and reduced energy costs are some of the benefits enjoyed by users of solar air heating. We identify the remaining hurdles to be addressed prior to widespread adoption of this technology in the built environment across the world.
      PubDate: 2017-02-22T08:57:02.547155-05:
      DOI: 10.1002/ente.201600758
       
  • Optical Activity of Chiral Nanoscrolls
    • Authors: Anvar S. Baimuratov; Yurii K. Gun'ko, Alexey G. Shalkovskiy, Alexander V. Baranov, Anatoly V. Fedorov, Ivan D. Rukhlenko
      Abstract: A first quantum-mechanical theory of chiral semiconductor nanoscrolls is presented. The theory allows one to analytically calculate the rotatory strengths and dissymmetry factors of optical transitions inside monodisperse ensembles of randomly oriented nanoscrolls, as well as to model the circular dichroism spectra of the ensembles. The theory predicts strong optical activity of semiconductor nanoscrolls upon both intraband and interband transitions, which makes them useful for various biochemical, biophysical, and nanophotonics applications. Specifically, the rotatory strengths of intraband and interband transitions were shown to reach values as high as 10−35 erg cm3, which is three to four orders of magnitude larger than the typical rotatory strengths of small chiral molecules.A simple analytical theory of the optical activity of chiral nanoscrolls is presented. The theory provides expressions for the rotatory strengths upon interband and intraband optical transitions inside semiconductor nanoscrolls, which can be useful for modeling and interpretation of chiroptical responses of nanoscroll ensembles fabricated by ultrasound exfoliation of semiconductor materials in the presence of chiral ligands.
      PubDate: 2017-02-21T09:46:29.533733-05:
      DOI: 10.1002/adom.201600982
       
  • Structural, Electrical, and Electrochemical Characteristics of
           LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (Ln=Pr, Sm, Gd) as Cathode Materials in
           Intermediate-Temperature Solid Oxide Fuel Cells
    • Authors: Donghwi Jeong; Areum Jun, Young-Wan Ju, Junji Hyodo, Jeeyoung Shin, Tatsumi Ishihara, Tak-Hyoung Lim, Guntae Kim
      Abstract: Layered perovskite oxides have received great attention as prospective cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) because of their high electrical conductivities and fast oxygen kinetics. Herein, we focus on the structural, electrical, and electrochemical properties of layered perovskites LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (LnBSCF, Ln=Pr, Sm, and Gd) as a cathode material for IT-SOFCs. Among the evaluated perovskites, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) showed the highest electrical conductivity, the highest oxygen content, and the highest values of the oxygen bulk diffusion coefficient (D*) and surface exchange coefficient (k) measured by using isotope oxygen exchange. The composite cathode of PBSCF and gadolinium-doped ceria is the most suitable cathode material for IT-SOFCs among the materials investigated because of its excellent electrochemical properties and fast oxygen kinetics.Killer kinetics: Oxygen kinetics are important: the surface exchange coefficient (k) and bulk diffusion coefficient (D*) are important parameters to determine the electrochemical performance of cathode materials for intermediate-temperature solid oxide fuel cells. The structural, electrical, and electrochemical properties of layered perovskites LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (Ln=Pr, Sm, Gd) are investigated systemically.
      PubDate: 2017-02-21T08:46:41.486974-05:
      DOI: 10.1002/ente.201600618
       
  • Structural, Electrical, and Electrochemical Characteristics of
           LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (Ln=Pr, Sm, Gd) as Cathode Materials in
           Intermediate-Temperature Solid Oxide Fuel Cells
    • Authors: Donghwi Jeong; Areum Jun, Young-Wan Ju, Junji Hyodo, Jeeyoung Shin, Tatsumi Ishihara, Tak-Hyoung Lim, Guntae Kim
      Abstract: Layered perovskite oxides have received great attention as prospective cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) because of their high electrical conductivities and fast oxygen kinetics. Herein, we focus on the structural, electrical, and electrochemical properties of layered perovskites LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (LnBSCF, Ln=Pr, Sm, and Gd) as a cathode material for IT-SOFCs. Among the evaluated perovskites, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) showed the highest electrical conductivity, the highest oxygen content, and the highest values of the oxygen bulk diffusion coefficient (D*) and surface exchange coefficient (k) measured by using isotope oxygen exchange. The composite cathode of PBSCF and gadolinium-doped ceria is the most suitable cathode material for IT-SOFCs among the materials investigated because of its excellent electrochemical properties and fast oxygen kinetics.Killer kinetics: Oxygen kinetics are important: the surface exchange coefficient (k) and bulk diffusion coefficient (D*) are important parameters to determine the electrochemical performance of cathode materials for intermediate-temperature solid oxide fuel cells. The structural, electrical, and electrochemical properties of layered perovskites LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (Ln=Pr, Sm, Gd) are investigated systemically.
      PubDate: 2017-02-21T08:46:41.486974-05:
      DOI: 10.1002/ente.201600618
       
  • CO2 Footprint and Life-Cycle Costs of Electrochemical Energy Storage for
           Stationary Grid Applications
    • Authors: M. Baumann; J. F. Peters, M. Weil, A. Grunwald
      Abstract: Batteries are considered as one of the key flexibility options for future energy storage systems. However, their production is cost- and greenhouse-gas intensive and efforts are made to decrease their price and carbon footprint. We combine life-cycle assessment, Monte-Carlo simulation, and size optimization to determine life-cycle costs and carbon emissions of different battery technologies in stationary applications, which are then compared by calculating a single score. Cycle life is determined as a key factor for cost and CO2 emissions. This is not only due to the required battery replacements but also due to oversizing needed for battery types with low cycle lives to reduce degradation effects. Most Li-ion but also the NaNiCl batteries show a good performance in all assessed applications whereas lead-acid batteries fall behind due to low cycle life and low internal efficiency. For redox-flow batteries, a high dependence on the desired application field is pointed out.Batteries to store and score: Optimization of the battery under dynamic charge–discharge scenarios helps minimizing carbon footprint and overall costs. Most Li-ion but also NaNiCl batteries show a good performance in all assessed applications whereas lead-acid batteries fall behind due to low cycle life and low efficiency. For redox-flow batteries, a high dependence on the application field is given. Cycle lifetime is another determining factor.
      PubDate: 2017-02-21T08:42:55.535915-05:
      DOI: 10.1002/ente.201600622
       
  • CO2 Footprint and Life-Cycle Costs of Electrochemical Energy Storage for
           Stationary Grid Applications
    • Authors: M. Baumann; J. F. Peters, M. Weil, A. Grunwald
      Abstract: Batteries are considered as one of the key flexibility options for future energy storage systems. However, their production is cost- and greenhouse-gas intensive and efforts are made to decrease their price and carbon footprint. We combine life-cycle assessment, Monte-Carlo simulation, and size optimization to determine life-cycle costs and carbon emissions of different battery technologies in stationary applications, which are then compared by calculating a single score. Cycle life is determined as a key factor for cost and CO2 emissions. This is not only due to the required battery replacements but also due to oversizing needed for battery types with low cycle lives to reduce degradation effects. Most Li-ion but also the NaNiCl batteries show a good performance in all assessed applications whereas lead-acid batteries fall behind due to low cycle life and low internal efficiency. For redox-flow batteries, a high dependence on the desired application field is pointed out.Batteries to store and score: Optimization of the battery under dynamic charge–discharge scenarios helps minimizing carbon footprint and overall costs. Most Li-ion but also NaNiCl batteries show a good performance in all assessed applications whereas lead-acid batteries fall behind due to low cycle life and low efficiency. For redox-flow batteries, a high dependence on the application field is given. Cycle lifetime is another determining factor.
      PubDate: 2017-02-21T08:42:55.535915-05:
      DOI: 10.1002/ente.201600622
       
  • Impact of Infinite Thin Flame Approach on the Evaluation of Flame Speed
           using Spherically Expanding Flames
    • Authors: Feichi Zhang; Tobias Baust, Thorsten Zirwes, Jordan Denev, Peter Habisreuther, Nikolaos Zarzalis, Henning Bockhorn
      Abstract: Combustion is an important part of most current and future overall energy-conversion systems, especially if using renewable fuels in energy-storage concepts. Therefore, the laminar flame speed, which is a key parameter for the design of combustion systems, needs to be known for a growing multitude of different thermodynamic conditions and fuels. The spherically expanding flame method is one of the few techniques that enables the flame speed to be measured under particular conditions such as elevated pressure and temperature as well as under turbulent conditions, which are important for energy-conversion applications. The radius of a spherically propagating flame is tracked and used for evaluation of the flame speed. Usually, the flame is assumed to be infinitely thin. To assess the influence of this assumption, direct numerical simulations were conducted for the experimental setup and compared with measurements and correlations from the literature. The flame speed determined by the consumption rate of fuel, which takes a finite thickness of the flame into account, was found to be always larger than the flame speed computed by assuming an infinitely thin flame. The difference between these flame speeds was observed to be as large as approximately 10–20 % in the evaluation range of the measured flame radii, which decreases with growing flame radius. This gives rise to the discrepancies in the flame speeds obtained from different measurement methods. An analytical estimation for this difference was developed as a function of the flame radius, which showed quantitatively good agreement with the simulation results and may be used for experimental validations of the flame speed. Both premixed H2/air and CH4/air flames with equivalence ratios ranging from lean to rich conditions were studied.Fuel the flames: Spherically expanding flames for different H2/air and CH4/air flames are studied experimentally and numerically. The flame's consumption speed is found to be larger than the flame speed, as deduced from the time derivative of the flame radii. A first-order estimation is derived to predict the differences between these flame speeds, and it shows good agreement with simulation results and can be further used for experimental validation.
      PubDate: 2017-02-20T08:40:40.739681-05:
      DOI: 10.1002/ente.201600573
       
  • Impact of Infinite Thin Flame Approach on the Evaluation of Flame Speed
           using Spherically Expanding Flames
    • Authors: Feichi Zhang; Tobias Baust, Thorsten Zirwes, Jordan Denev, Peter Habisreuther, Nikolaos Zarzalis, Henning Bockhorn
      Abstract: Combustion is an important part of most current and future overall energy-conversion systems, especially if using renewable fuels in energy-storage concepts. Therefore, the laminar flame speed, which is a key parameter for the design of combustion systems, needs to be known for a growing multitude of different thermodynamic conditions and fuels. The spherically expanding flame method is one of the few techniques that enables the flame speed to be measured under particular conditions such as elevated pressure and temperature as well as under turbulent conditions, which are important for energy-conversion applications. The radius of a spherically propagating flame is tracked and used for evaluation of the flame speed. Usually, the flame is assumed to be infinitely thin. To assess the influence of this assumption, direct numerical simulations were conducted for the experimental setup and compared with measurements and correlations from the literature. The flame speed determined by the consumption rate of fuel, which takes a finite thickness of the flame into account, was found to be always larger than the flame speed computed by assuming an infinitely thin flame. The difference between these flame speeds was observed to be as large as approximately 10–20 % in the evaluation range of the measured flame radii, which decreases with growing flame radius. This gives rise to the discrepancies in the flame speeds obtained from different measurement methods. An analytical estimation for this difference was developed as a function of the flame radius, which showed quantitatively good agreement with the simulation results and may be used for experimental validations of the flame speed. Both premixed H2/air and CH4/air flames with equivalence ratios ranging from lean to rich conditions were studied.Fuel the flames: Spherically expanding flames for different H2/air and CH4/air flames are studied experimentally and numerically. The flame's consumption speed is found to be larger than the flame speed, as deduced from the time derivative of the flame radii. A first-order estimation is derived to predict the differences between these flame speeds, and it shows good agreement with simulation results and can be further used for experimental validation.
      PubDate: 2017-02-20T08:40:40.739681-05:
      DOI: 10.1002/ente.201600573
       
  • Cover Picture: Cetyltrimethylammonium Bromide-Promoted, ZnO-Supported, and
           Mn-Promoted Cu–Fe Catalyst for the Hydrogenation of CO to Low-Carbon
           Alcohols (Energy Technol. 4/2017)
    • Authors: Wei Hu; Wei Li, Rongchun Shen
      Pages: 520 - 520
      Abstract: Efficient catalyst: The cover image demonstrates the synthesis of low-carbon (C2–C4) alcohols from syngas using cetyltrimethylammonium bromide-promoted, ZnO-supported, and Mn-promoted Cu–Fe catalysts. Although Cu–Fe based catalysts produce a large amount of hydrocarbons, their high catalytic activity and strong ability to synthetize long-chain alcohols still attract significant attention. This work demonstrates that the Cu species are well reduced on the ZnO support and the Cu0/Cu+ ratio on the surface increased as a result of catalyst modification. Cu–Fe3C dual active sites are generated on the flower-shaped cetyltrimethylammonium bromide-promoted MnCuFe/ZnO catalyst. The performance study demonstrates that the formation rate of total alcohols is enhanced (and low-carbon alcohols even more so) at a relatively high level of catalytic activity. More details can be found in the Full Paper by Wei Li and colleagues at East China University of Science and Technology on page 557 in Issue 4, 2017 (
      DOI : 10.1002/ente.201600366).
      PubDate: 2017-03-29T09:15:46.716376-05:
       
  • Cover Picture: Cetyltrimethylammonium Bromide-Promoted, ZnO-Supported, and
           Mn-Promoted Cu–Fe Catalyst for the Hydrogenation of CO to Low-Carbon
           Alcohols (Energy Technol. 4/2017)
    • Authors: Wei Hu; Wei Li, Rongchun Shen
      Pages: 520 - 520
      Abstract: Efficient catalyst: The cover image demonstrates the synthesis of low-carbon (C2–C4) alcohols from syngas using cetyltrimethylammonium bromide-promoted, ZnO-supported, and Mn-promoted Cu–Fe catalysts. Although Cu–Fe based catalysts produce a large amount of hydrocarbons, their high catalytic activity and strong ability to synthetize long-chain alcohols still attract significant attention. This work demonstrates that the Cu species are well reduced on the ZnO support and the Cu0/Cu+ ratio on the surface increased as a result of catalyst modification. Cu–Fe3C dual active sites are generated on the flower-shaped cetyltrimethylammonium bromide-promoted MnCuFe/ZnO catalyst. The performance study demonstrates that the formation rate of total alcohols is enhanced (and low-carbon alcohols even more so) at a relatively high level of catalytic activity. More details can be found in the Full Paper by Wei Li and colleagues at East China University of Science and Technology on page 557 in Issue 4, 2017 (
      DOI : 10.1002/ente.201600366).
      PubDate: 2017-03-29T09:15:46.716376-05:
       
  • Development of Combustion Technology for Methane Emitted from Coal-Mine
           Ventilation Air Systems
    • Authors: Adi Setiawan; Eric M. Kennedy, Michael Stockenhuber
      Pages: 521 - 538
      Abstract: Fugitive gas emissions from coal mining are widely known to be significant contributors to the emission of alkanes, mainly methane, to the environment. Utilization of coal-mine ventilation air methane (VAM) is a crucial mission to minimize methane emission in the atmosphere. This paper reviews current technology for mitigation and utilization of methane emissions from coal mining. Challenges and opportunities for each technology are discussed together with their benefits/disadvantages. Catalytic combustion technology is recommended as the best option due to the low and variable concentration of methane in coal-mine ventilation air, as well as its high volumetric flow. Herein, current developments in flameless combustion are discussed in detail with a few highlights on palladium-based catalyst development. The remaining uncertainties and obstacles in the development of palladium-based catalysts for VAM are also discussed. This paper highlights a few important practical aspects that necessitate further detailed investigation, such as catalyst deactivation phenomena, the stability of the catalyst under humid conditions, and the effect of coal dust on catalytic activity and stability. Notably, a pressure decrease, heat recovery/self-sustaining, and long-term deactivation are key for the successful development of VAM catalytic combustors.Breathe easy: Coal-mine methane leaks into the atmosphere and urges action from stakeholders to mitigate/utilize emissions. The challenges and opportunities of any technological options are discussed, together with their benefits and drawbacks. Particular focus is given to current progress in flameless combustion technology with highlights on palladium-based catalyst development and important practical aspects that necessitate further investigation.
      PubDate: 2017-01-31T07:08:30.160114-05:
      DOI: 10.1002/ente.201600490
       
  • Development of Combustion Technology for Methane Emitted from Coal-Mine
           Ventilation Air Systems
    • Authors: Adi Setiawan; Eric M. Kennedy, Michael Stockenhuber
      Pages: 521 - 538
      Abstract: Fugitive gas emissions from coal mining are widely known to be significant contributors to the emission of alkanes, mainly methane, to the environment. Utilization of coal-mine ventilation air methane (VAM) is a crucial mission to minimize methane emission in the atmosphere. This paper reviews current technology for mitigation and utilization of methane emissions from coal mining. Challenges and opportunities for each technology are discussed together with their benefits/disadvantages. Catalytic combustion technology is recommended as the best option due to the low and variable concentration of methane in coal-mine ventilation air, as well as its high volumetric flow. Herein, current developments in flameless combustion are discussed in detail with a few highlights on palladium-based catalyst development. The remaining uncertainties and obstacles in the development of palladium-based catalysts for VAM are also discussed. This paper highlights a few important practical aspects that necessitate further detailed investigation, such as catalyst deactivation phenomena, the stability of the catalyst under humid conditions, and the effect of coal dust on catalytic activity and stability. Notably, a pressure decrease, heat recovery/self-sustaining, and long-term deactivation are key for the successful development of VAM catalytic combustors.Breathe easy: Coal-mine methane leaks into the atmosphere and urges action from stakeholders to mitigate/utilize emissions. The challenges and opportunities of any technological options are discussed, together with their benefits and drawbacks. Particular focus is given to current progress in flameless combustion technology with highlights on palladium-based catalyst development and important practical aspects that necessitate further investigation.
      PubDate: 2017-01-31T07:08:30.160114-05:
      DOI: 10.1002/ente.201600490
       
  • A Dual-Carbon Phase-Modified and Nanostructured Nickel Sulfide Anode for
           Sodium-Ion Batteries
    • Authors: Fei Han; Clara Yi Jun Tan, Zhiqiang Gao
      Pages: 580 - 587
      Abstract: On the basis of the concept of a nanoconfinement reaction, a synthetic strategy was developed to construct ultrathin carbon-film-coated and nanostructured nickel sulfide anchored on carbon nanotubes (CNTs). The synthesis involved the direct growth of nickel hydroxide on the CNTs followed by dehydration, sulfidation, and carbon coating. If used as an anode material in sodium-ion batteries (SIBs), the nickel sulfide-based anode showed a high utilization rate of the active material and a favorable specific capacity of 390 mAh g−1. The excellent performance of the nickel sulfide-based anode in SIBs demonstrates the potential of nickel sulfide to be used as the anode material in SIBs if it is engineered to alleviate its structural constraints. In principle, this strategy can be conveniently adapted to engineer other transition-metal-based materials for applications in energy storage.Just a little nick: A synthetic strategy is developed to construct dual-carbon phase modified and nanostructured nickel sulfide. If used as an anode material in a sodium-ion battery, the nickel sulfide based anode gives a specific capacity of 390 mAh g−1 and has excellent cycle life.
      PubDate: 2017-01-09T05:20:37.663471-05:
      DOI: 10.1002/ente.201600393
       
  • A Dual-Carbon Phase-Modified and Nanostructured Nickel Sulfide Anode for
           Sodium-Ion Batteries
    • Authors: Fei Han; Clara Yi Jun Tan, Zhiqiang Gao
      Pages: 580 - 587
      Abstract: On the basis of the concept of a nanoconfinement reaction, a synthetic strategy was developed to construct ultrathin carbon-film-coated and nanostructured nickel sulfide anchored on carbon nanotubes (CNTs). The synthesis involved the direct growth of nickel hydroxide on the CNTs followed by dehydration, sulfidation, and carbon coating. If used as an anode material in sodium-ion batteries (SIBs), the nickel sulfide-based anode showed a high utilization rate of the active material and a favorable specific capacity of 390 mAh g−1. The excellent performance of the nickel sulfide-based anode in SIBs demonstrates the potential of nickel sulfide to be used as the anode material in SIBs if it is engineered to alleviate its structural constraints. In principle, this strategy can be conveniently adapted to engineer other transition-metal-based materials for applications in energy storage.Just a little nick: A synthetic strategy is developed to construct dual-carbon phase modified and nanostructured nickel sulfide. If used as an anode material in a sodium-ion battery, the nickel sulfide based anode gives a specific capacity of 390 mAh g−1 and has excellent cycle life.
      PubDate: 2017-01-09T05:20:37.663471-05:
      DOI: 10.1002/ente.201600393
       
  • Metal Organic Framework-Derived Cobalt Dicarboxylate as a High-Capacity
           Anode Material for Lithium-ion Batteries
    • Authors: Liping Wang; Mingjuan Zhao, Jiliang Qiu, Peng Gao, Jing Xue, Jingze Li
      Pages: 637 - 642
      Abstract: Considerable attention has been paid to metal-organic frameworks (MOFs) for applications as electrode materials for lithium-ion batteries recently. In this study, we use cobalt terephthalate CoC8H4O4 (CoTPA), one type of MOFs, as an anode material for lithium-ion batteries for the first time. It delivers a high discharge capacity of about 700 mAh g−1 after 100 cycles with superior capacity retention. In contrast to the conventional lithium-storage mechanism of MOF-based anodes in organic carbonyl units, both the inorganic unit (Co2+) and the organic unit (carbonyl group) offer multi-electron transfer reactions, which results in such a high capacity.New terephthalate glory: Crystalline metal-organic frameworks (MOFs) have attracted considerable interest as electrode materials for lithium-ion batteries. However, MOF electrodes reported so far have a low capacity and poor capacity retention behavior owing to limited electron transfer reaction and active sites. We have synthesized MOF-based cobalt terephthalate and used it as an anode material for lithium-ion batteries, showing a high discharge capacity and excellent cycle life.
      PubDate: 2017-01-04T03:05:32.060194-05:
      DOI: 10.1002/ente.201600424
       
 
 
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