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Publisher: John Wiley and Sons   (Total: 1583 journals)

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Showing 1 - 200 of 1583 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 11, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 53, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 43, SJR: 0.547, h-index: 30)
ACEP NOW     Free  
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 50, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 133, 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: 54, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 7, 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: 5, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 2)
Addiction     Hybrid Journal   (Followers: 32, 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: 24, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 48, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 13, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 246, 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: 4, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 4)
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: 33, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 14, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 15, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 9, 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: 28, 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: 33, 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: 127, 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: 89, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 28, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 30, 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 Orthopsychiatry     Hybrid Journal   (Followers: 4, SJR: 0.756, h-index: 69)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 35, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 237, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 14, 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: 15, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 116, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 11, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 15)
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: 153)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 203, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 34, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 5, 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: 42, 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: 16, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 14)
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: 92, 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: 66, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 6, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 130, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 47, 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: 13, 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: 24, 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: 203, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 48, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 27, 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: 13)
Asia & the Pacific Policy Studies     Open Access   (Followers: 15)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 319, 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: 3, 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: 13, 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: 12, 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: 7, 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: 3, 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: 42, 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: 6, 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: 22, 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: 16, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 383, 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: 64, 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: 9, 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: 3, 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: 7, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 21, 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: 14, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 2, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 44, 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: 135, 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: 17, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 10, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 33, 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)

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Journal Cover Advanced Materials
  [SJR: 9.021]   [H-I: 345]   [246 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0935-9648 - ISSN (Online) 1521-4095
   Published by John Wiley and Sons Homepage  [1583 journals]
  • Wet-Chemical Synthesis of Hollow Red-Phosphorus Nanospheres with Porous
           Shells as Anodes for High-Performance Lithium-Ion and Sodium-Ion Batteries
           
    • Authors: Jianbin Zhou; Xianyu Liu, Wenlong Cai, Yongchun Zhu, Jianwen Liang, Kailong Zhang, Yang Lan, Zhuoheng Jiang, Gongming Wang, Yitai Qian
      Abstract: Large-volume-expansion-induced material pulverization severely limits the electrochemical performance of red phosphorous (P) for energy-storage applications. Hollow nanospheres with porous shells are recognized as an ideal structure to resolve these issues. However, a chemical synthetic approach for preparing nanostructured red P is always of great challenge and hollow nanosphere structures of red P have not yet been fabricated. Herein, a wet solvothermal method to successfully fabricate hollow P nanospheres (HPNs) with porous shells via a gas-bubble-directed formation mechanism is developed. More importantly, due to the merits of the porous and hollow structures, these HPNs reveal the highest capacities (based on the weight of electrode materials) of 1285.7 mA h g−1 for lithium-ion batteries and 1364.7 mA h g−1 for sodium-ion batteries at 0.2 C, and excellent long-cycling performance.Preparing nanostructured phosphorus by a chemical synthetic approach is always challenging. A wet solvothermal method is developed to fabricate hollow phosphorous nanospheres (HPNs) with porous shells via a gas-bubble-directed formation mechanism. More importantly, due to the merits of porous and hollow structures, HPNs reveal excellent electrochemical performance as anodes for lithium-ion and sodium-ion batteries.
      PubDate: 2017-05-26T00:40:42.57855-05:0
      DOI: 10.1002/adma.201700214
       
  • Reduced Interface-Mediated Recombination for High Open-Circuit Voltages in
           CH3NH3PbI3 Solar Cells
    • Authors: Christian M. Wolff; Fengshuo Zu, Andreas Paulke, Lorena Perdigón Toro, Norbert Koch, Dieter Neher
      Abstract: Perovskite solar cells with all-organic transport layers exhibit efficiencies rivaling their counterparts that employ inorganic transport layers, while avoiding high-temperature processing. Herein, it is investigated how the choice of the fullerene derivative employed in the electron-transporting layer of inverted perovskite cells affects the open-circuit voltage (VOC). It is shown that nonradiative recombination mediated by the electron-transporting layer is the limiting factor for the VOC in the cells. By inserting an ultrathin layer of an insulating polymer between the active CH3NH3PbI3 perovskite and the fullerene, an external radiative efficiency of up to 0.3%, a VOC as high as 1.16 V, and a power conversion efficiency of 19.4% are realized. The results show that the reduction of nonradiative recombination due to charge-blocking at the perovskite/organic interface is more important than proper level alignment in the search for ideal selective contacts toward high VOC and efficiency.Perovskite solar cells have emerged as one of the most promising solar-cell technologies for the next generation of photovoltaics. Despite simple and cheap processing, the solar cells exhibit comparably little loss in open-circuit voltage. An approach to further reduce this loss by optimizing the charge selectivity of the fullerene-based electron contact in efficient devices is shown.
      PubDate: 2017-05-26T00:40:34.112221-05:
      DOI: 10.1002/adma.201700159
       
  • Thermally Stable MAPbI3 Perovskite Solar Cells with Efficiency of 19.19%
           and Area over 1 cm2 achieved by Additive Engineering
    • Authors: Yongzhen Wu; Fengxian Xie, Han Chen, Xudong Yang, Huimin Su, Molang Cai, Zhongmin Zhou, Takeshi Noda, Liyuan Han
      Abstract: Solution-processed perovskite (PSC) solar cells have achieved extremely high power conversion efficiencies (PCEs) over 20%, but practical application of this photovoltaic technology requires further advancements on both long-term stability and large-area device demonstration. Here, an additive-engineering strategy is developed to realize a facile and convenient fabrication method of large-area uniform perovskite films composed of large crystal size and low density of defects. The high crystalline quality of the perovskite is found to simultaneously enhance the PCE and the durability of PSCs. By using the simple and widely used methylammonium lead iodide (MAPbI3), a certified PCE of 19.19% is achieved for devices with an aperture area of 1.025 cm2, and the high-performing devices can sustain over 80% of the initial PCE after 500 h of thermal aging at 85 °C, which are among the best results of MAPbI3-based PSCs so far.By enhancing the crystalline quality of the simple and widely used MAPbI3 perovskite through additive engineering, unprecedented photovoltaic performance and thermal stability are achieved. A certified efficiency of 19.19% is obtained for devices with active area over 1 cm2, and the high-performing devices show unprecedented durability, maintaining >80% of the initial efficiency after 500 h of thermal aging at 85 °C.
      PubDate: 2017-05-19T07:21:25.768018-05:
      DOI: 10.1002/adma.201701073
       
  • Towards Efficient Spectral Converters through Materials Design for
           Luminescent Solar Devices
    • Authors: Barry McKenna; Rachel C. Evans
      Abstract: Single-junction photovoltaic devices exhibit a bottleneck in their efficiency due to incomplete or inefficient harvesting of photons in the low- or high-energy regions of the solar spectrum. Spectral converters can be used to convert solar photons into energies that are more effectively captured by the photovoltaic device through a photoluminescence process. Here, recent advances in the fields of luminescent solar concentration, luminescent downshifting, and upconversion are discussed. The focus is specifically on the role that materials science has to play in overcoming barriers in the optical performance in all spectral converters and on their successful integration with both established (e.g., c-Si, GaAs) and emerging (perovskite, organic, dye-sensitized) cell types. Current challenges and emerging research directions, which need to be addressed for the development of next-generation luminescent solar devices, are also discussed.Sspectral converters can be applied to finished solar cells to overcome intrinsic non-absorption and thermalization losses and improve the device efficiency. Recent progress in the development of new materials for spectral conversion through luminescent downshifting, luminescent solar concentration, and upconversion is reviewed, with emphasis placed on their integration with emerging technologies, including perovskite, organic, and dye-sensitized solar cells.
      PubDate: 2017-05-19T07:16:27.682826-05:
      DOI: 10.1002/adma.201606491
       
  • Tuning of the Optical, Electronic, and Magnetic Properties of Boron
           Nitride Nanosheets with Oxygen Doping and Functionalization
    • Authors: Qunhong Weng; Dmitry G. Kvashnin, Xi Wang, Ovidiu Cretu, Yijun Yang, Min Zhou, Chao Zhang, Dai-Ming Tang, Pavel B. Sorokin, Yoshio Bando, Dmitri Golberg
      Abstract: Engineering of the optical, electronic, and magnetic properties of hexagonal boron nitride (h-BN) nanomaterials via oxygen doping and functionalization has been envisaged in theory. However, it is still unclear as to what extent these properties can be altered using such methodology because of the lack of significant experimental progress and systematic theoretical investigations. Therefore, here, comprehensive theoretical predictions verified by solid experimental confirmations are provided, which unambiguously answer this long-standing question. Narrowing of the optical bandgap in h-BN nanosheets (from ≈5.5 eV down to 2.1 eV) and the appearance of paramagnetism and photoluminescence (of both Stokes and anti-Stokes types) in them after oxygen doping and functionalization are discussed. These results are highly valuable for further advances in semiconducting nanoscale electronics, optoelectronics, and spintronics.Intense oxygen doping and functionalization of hexagonal boron nitride (h-BN) nanosheets narrow the bandgap of the material from ≈5.5 to 2.1 eV in experiments, and lead to the appearance of paramagnetism and photoluminescence properties, which are not seen in h-BN. These findings pave a new way for the engineering of the optical, electronic, and magnetic properties of BN nanosheets.
      PubDate: 2017-05-19T01:31:29.07504-05:0
      DOI: 10.1002/adma.201700695
       
  • Bioinspired Composite Microfibers for Skin Adhesion and Signal
           Amplification of Wearable Sensors
    • Authors: Dirk-M. Drotlef; Morteza Amjadi, Muhammad Yunusa, Metin Sitti
      Abstract: A facile approach is proposed for superior conformation and adhesion of wearable sensors to dry and wet skin. Bioinspired skin-adhesive films are composed of elastomeric microfibers decorated with conformal and mushroom-shaped vinylsiloxane tips. Strong skin adhesion is achieved by crosslinking the viscous vinylsiloxane tips directly on the skin surface. Furthermore, composite microfibrillar adhesive films possess a high adhesion strength of 18 kPa due to the excellent shape adaptation of the vinylsiloxane tips to the multiscale roughness of the skin. As a utility of the skin-adhesive films in wearable-device applications, they are integrated with wearable strain sensors for respiratory and heart-rate monitoring. The signal-to-noise ratio of the strain sensor is significantly improved to 59.7 because of the considerable signal amplification of microfibrillar skin-adhesive films.Strong adhesion of wearable sensors to dry and wet skin is proposed by a novel approach. Micropatterned adhesive films are composed of microfibers decorated with mushroom-shaped vinylsiloxane tips. Crosslinking the viscous tips directly on the skin significantly enhances the adhesion performance due to their great shape adaptation, which in turn highly increases the output signal quality of wearable strain sensors.
      PubDate: 2017-05-19T01:31:23.950918-05:
      DOI: 10.1002/adma.201701353
       
  • Biphasic Supramolecular Self-Assembly of Ferric Ions and Tannic Acid
           across Interfaces for Nanofilm Formation
    • Authors: Beom Jin Kim; Sol Han, Kyung-Bok Lee, Insung S. Choi
      Abstract: Cell nanoencapsulation provides a chemical tool for the isolation and protection of living cells from harmful, and often lethal, external environments. Although several strategies are available to form nanometric films, most methods heavily rely on time-consuming multistep processes and are not biocompatible. Here, the interfacial supramolecular self-assembly and film formation of ferric ions (FeIII) and tannic acid (TA) in biphasic systems is reported, where FeIII and TA come into contact each other and self-assemble across the interface of two immiscible phases. The interfacial nanofilm formation developed is simple, fast, and cytocompatible. Its versatility is demonstrated with various biphasic systems: hollow microcapsules, encasing microbial or mammalian cells, that are generated at the water–oil interface in a microfluidic device; a cytoprotective FeIII–TA shell that forms on the surface of the alginate microbead, which then entraps probiotic Lactobacillus acidophilus; and a pericellular FeIII–TA shell that forms on individual Saccharomyces cerevisiae. This biphasic interfacial reaction system provides a simple but versatile structural motif in materials science, as well as advancing chemical manipulability of living cells.The biphasic interfacial supramolecular self-assembly of ferric ions (FeIII) and tannic acid in a heterogeneous system provides a powerful method for the formation of uniform and stable nanofilms in one step. The versatility of the synthetic strategy is demonstrated under various experimental settings (water–oil, hydrogel–water, and cell–water biphasic systems).
      PubDate: 2017-05-19T01:31:16.805203-05:
      DOI: 10.1002/adma.201700784
       
  • Bioinspired Ultratough Hydrogel with Fast Recovery, Self-Healing,
           Injectability and Cytocompatibility
    • Authors: Sara Azevedo; Ana M. S. Costa, Amanda Andersen, Insung S. Choi, Henrik Birkedal, João F. Mano
      Abstract: Inspired by the mussel byssus adhesiveness, a highly hydrated polymeric structure is designed to combine, for the first time, a set of interesting features for load-bearing purposes. These characteristics include: i) a compressive strength and stiffness in the MPa range, ii) toughness and the ability to recover it upon successive cyclic loading, iii) the ability to quickly self-heal upon rupture, iv) the possibility of administration through minimally invasive techniques, such as by injection, v) the swelling ratio being adjusted to space-filling applications, and vi) cytocompatibility. Owing to these characteristics and the mild conditions employed, the encapsulation of very unstable and sensitive cargoes is possible, highlighting their potential to researchers in the biomedical field for the repair of load-bearing soft tissues, or to be used as an encapsulation platform for a variety of biological applications such as disease models for drug screening and therapies in a more realistic mechanical environment. Moreover, given the simplicity of this methodology and the enhanced mechanical performance, this strategy can be expanded to applications in other fields, such as agriculture and electronics. As such, it is anticipated that the proposed strategy will constitute a new, versatile, and cost-effective tool to produce engineered polymeric structures for both science and technology.Inspired by the mussel byssus attachment system, a self-healable, ultratough and strong hydrogel is reported. The mild conditions employed during the fabrication process, as well as the use of nature-based materials, make it a prospective candidate for a wide range of applications including in the biomedical field.
      PubDate: 2017-05-19T01:31:11.991919-05:
      DOI: 10.1002/adma.201700759
       
  • Synergistic Phase and Disorder Engineering in 1T-MoSe2 Nanosheets for
           Enhanced Hydrogen-Evolution Reaction
    • Authors: Ying Yin; Yumin Zhang, Tangling Gao, Tai Yao, Xinghong Zhang, Jiecai Han, Xianjie Wang, Zhihua Zhang, Ping Xu, Peng Zhang, Xingzhong Cao, Bo Song, Song Jin
      Abstract: MoSe2 is a promising earth-abundant electrocatalyst for the hydrogen-evolution reaction (HER), even though it has received much less attention among the layered dichalcogenide (MX2) materials than MoS2 so far. Here, a novel hydrothermal-synthesis strategy is presented to achieve simultaneous and synergistic modulation of crystal phase and disorder in partially crystallized 1T-MoSe2 nanosheets to dramatically enhance their HER catalytic activity. Careful structural characterization and defect characterization using positron annihilation lifetime spectroscopy correlated with electrochemical measurements show that the formation of the 1T phase under a large excess of the NaBH4 reductant during synthesis can effectively improve the intrinsic activity and conductivity, and the disordered structure from a lower reaction temperature can provide abundant unsaturated defects as active sites. Such synergistic effects lead to superior HER catalytic activity with an overpotential of 152 mV versus reversible hydrogen electrode (RHE) for the electrocatalytic current density of j = −10 mA cm−2, and a Tafel slope of 52 mV dec−1. This work paves a new pathway for improving the catalytic activity of MoSe2 and generally MX2-based electrocatalysts via a synergistic modulation strategy.Synergistic regulation of crystal phase and disorder engineering in partially crystallized 1T phase MoSe2 nanosheets that are directly hydrothermally synthesized enhances catalytic activity toward the hydrogen-evolution reaction (HER). The optimized MoSe2 nanosheets exhibit a record-high HER catalytic activity, with η = 152 mV versus RHE for j = −10 mA cm−2 and a Tafel slope of 52 mV dec−1.
      PubDate: 2017-05-19T01:31:07.807033-05:
      DOI: 10.1002/adma.201700311
       
  • Mushrooms as Efficient Solar Steam-Generation Devices
    • Authors: Ning Xu; Xiaozhen Hu, Weichao Xu, Xiuqiang Li, Lin Zhou, Shining Zhu, Jia Zhu
      Abstract: Solar steam generation is emerging as a promising technology, for its potential in harvesting solar energy for various applications such as desalination and sterilization. Recent studies have reported a variety of artificial structures that are designed and fabricated to improve energy conversion efficiencies by enhancing solar absorption, heat localization, water supply, and vapor transportation. Mushrooms, as a kind of living organism, are surprisingly found to be efficient solar steam-generation devices for the first time. Natural and carbonized mushrooms can achieve ≈62% and ≈78% conversion efficiencies under 1 sun illumination, respectively. It is found that this capability of high solar steam generation is attributed to the unique natural structure of mushroom, umbrella-shaped black pileus, porous context, and fibrous stipe with a small cross section. These features not only provide efficient light absorption, water supply, and vapor escape, but also suppress three components of heat losses at the same time. These findings not only reveal the hidden talent of mushrooms as low-cost materials for solar steam generation, but also provide inspiration for the future development of high-performance solar thermal conversion devices.Mushrooms can, surprisingly, enable efficient solar steam generation (≈78% under 1 sun illumination), as their natural structures possess the excellent properties of light absorption, thermal management with minimized heat loss, efficient water supply, and vapor escape.
      PubDate: 2017-05-18T07:32:05.561466-05:
      DOI: 10.1002/adma.201606762
       
  • Core–Shell and Layer-by-Layer Assembly of 3D DNA Crystals
    • Authors: Ronald McNeil; Paul J. Paukstelis
      Abstract: A long-standing goal of DNA nanotechnology has been to assemble 3D crystals to be used as molecular scaffolds. The DNA 13-mer, BET66, self-assembles via Crick–Watson and noncanonical base pairs to form crystals. The crystals contain solvent channels that run through them in multiple directions, allowing them to accommodate tethered guest molecules. Here, the first example of biomacromolecular core–shell crystal growth is described, by showing that these crystals can be assembled with two or more discrete layers. This approach leads to structurally identical layers on the DNA level, but with each layer differentiated based on the presence or absence of conjugated guest molecules. The crystal solvent channels also allow layer-specific postcrystallization covalent attachment of guest molecules. Through controlling the guest-molecule identity, concentration, and layer thickness, this study opens up a new method for using DNA to create multifunctional periodic biomaterials with tunable optical, chemical, and physical properties.Multifunctional DNA-based biomaterial solids are generated through core–shell and layer-by-layer crystal growth. The isothermal self-assembly properties of the DNA crystal allow stepwise incorporation of functionally modified oligonucleotides to create layered periodic arrays of “guest” molecules, with each layer differentiated by the identity of the tethered guest molecules.
      PubDate: 2017-05-18T07:31:58.895095-05:
      DOI: 10.1002/adma.201701019
       
  • Contents: (Adv. Mater. 20/2017)
    • PubDate: 2017-05-18T07:29:30.448006-05:
      DOI: 10.1002/adma.201770135
       
  • Materials Research at Wuhan University of Technology
    • Authors: Liqiang Mai; Qingjie Zhang, Ce-Wen Nan
      PubDate: 2017-05-18T07:29:30.301152-05:
      DOI: 10.1002/adma.201701082
       
  • Wuhan University of Technology (Adv. Mater. 20/2017)
    • Abstract: Wuhan University of Technology has served as a cradle of talent for sci–tech innovation and a base for regional economic construction, and aims to become a first-class university in China and to be an internationally renowned institution. The library at South Lake Campus is one symbol of the new beautiful chapter in the university's history.
      PubDate: 2017-05-18T07:29:28.275666-05:
      DOI: 10.1002/adma.201770141
       
  • Thermoelectric Materials: Multi-Scale Microstructural Thermoelectric
           Materials: Transport Behavior, Non-Equilibrium Preparation, and
           Applications (Adv. Mater. 20/2017)
    • Authors: Xianli Su; Ping Wei, Han Li, Wei Liu, Yonggao Yan, Peng Li, Chuqi Su, Changjun Xie, Wenyu Zhao, Pengcheng Zhai, Qingjie Zhang, Xinfeng Tang, Ctirad Uher
      Abstract: In article number 1602013, Qingjie Zhang, Xinfeng Tang, Ctirad Uher, and co-workers review the transport behavior, non-equilibrium preparation, and applications of multi-scale microstructural thermoelectric materials. Led by Wuhan University of Technology, the world's first 100 kW solar thermoelectric–photovoltaic hybrid power-generation system has been built in Qinghai Province, China.
      PubDate: 2017-05-18T07:29:25.934428-05:
      DOI: 10.1002/adma.201770137
       
  • Energy Storage: Porous One-Dimensional Nanomaterials: Design, Fabrication
           and Applications in Electrochemical Energy Storage (Adv. Mater. 20/2017)
    • Authors: Qiulong Wei; Fangyu Xiong, Shuangshuang Tan, Lei Huang, Esther H. Lan, Bruce Dunn, Liqiang Mai
      Abstract: In article number 1602300, Bruce Dunn, Liqiang Mai, and co-workers present an overview of emerging novel, porous, one-dimensional nanostructures: from methodologies for rational and controllable synthesis to their successful application in different types of energy-storage devices, including lithium-ion batteries, sodium-ion batteries, lithium–sulfur batteries, lithium–oxygen batteries, and supercapacitors.
      PubDate: 2017-05-18T07:29:25.205646-05:
      DOI: 10.1002/adma.201770134
       
  • Organic Photovoltaics: Conjugated-Polymer Blends for Organic
           Photovoltaics: Rational Control of Vertical Stratification for High
           Performance (Adv. Mater. 20/2017)
    • Authors: Yu Yan; Xuan Liu, Tao Wang
      Abstract: In article number 1601674, Tao Wang and co-workers review conjugated-polymer blends for organic photovoltaics. The distributions of electron donors and electron acceptors are usually heterogeneous in the vertical direction of the conjugated-polymer photoactive layer, and can significantly influence the photovoltaic performance through their impacts on charge transport and recombination.
      PubDate: 2017-05-18T07:29:23.814319-05:
      DOI: 10.1002/adma.201770138
       
  • Perovskite Solar Cells: Effect of the Microstructure of the Functional
           Layers on the Efficiency of Perovskite Solar Cells (Adv. Mater. 20/2017)
    • Authors: Fuzhi Huang; Alexander R. Pascoe, Wu-Qiang Wu, Zhiliang Ku, Yong Peng, Jie Zhong, Rachel A. Caruso, Yi-Bing Cheng
      Abstract: Pinhole-free, dense perovskite films with large grains, which can be achieved by control of the nucleation and crystal growth, are essential for high-performance perovskite solar cells. These perovskite-solar-cell systems are discussed by Fuzhi Huang, Yi-Bing Cheng, and co-workers in article number 1601715.
      PubDate: 2017-05-18T07:29:23.741552-05:
      DOI: 10.1002/adma.201770139
       
  • Masthead: (Adv. Mater. 20/2017)
    • PubDate: 2017-05-18T07:29:22.959753-05:
      DOI: 10.1002/adma.201770136
       
  • Wuhan University of Technology: (Adv. Mater. 20/2017)
    • Abstract: Wuhan University of Technology, a vigorous Chinese university forging ahead in both scientific and technological fields, celebrates the 30th Anniversary of the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing. The spirited flying-horse statue in Feima Square embodies the university's motto “Sound in Morality, Broad in Learning and Pursuing Excellence”.
      PubDate: 2017-05-18T07:29:21.917553-05:
      DOI: 10.1002/adma.201770133
       
  • Proteomics: New Opportunities and Challenges of Smart Polymers in
           Post-Translational Modification Proteomics (Adv. Mater. 20/2017)
    • Authors: Guangyan Qing; Qi Lu, Yuting Xiong, Lei Zhang, Hongxi Wang, Xiuling Li, Xinmiao Liang, Taolei Sun
      Abstract: Polymer-based phosphopeptide or glycopeptide enrichment materials are reviewed by Taolei Sun and co-workers in article number 1604670. In addition to high grafting densities and abundant binding sites, smart polymers display a dramatic conformational transition from globule to coil upon complexation with target peptides, enabling highly controllable binding/release behaviors of the peptides on material surfaces, which opens up a unique approach toward resolving the enrichment problems in post-translational modification proteomics.
      PubDate: 2017-05-18T07:29:21.861572-05:
      DOI: 10.1002/adma.201770140
       
  • An All-Plastic Field-Effect Nanofluidic Diode Gated by a Conducting
           Polymer Layer
    • Authors: Gonzalo Pérez-Mitta; Waldemar A. Marmisollé, Christina Trautmann, María Eugenia Toimil-Molares, Omar Azzaroni
      Abstract: The design of an all-plastic field-effect nanofluidic diode is proposed, which allows precise nanofluidic operations to be performed. The fabrication process involves the chemical synthesis of a conductive poly(3,4-ethylenedioxythiophene) (PEDOT) layer over a previously fabricated solid-state nanopore. The conducting layer acts as gate electrode by changing its electrochemical state upon the application of different voltages, ultimately changing the surface charge of the nanopore. A PEDOT-based nanopore is able to discriminate the ionic species passing through it in a quantitative and qualitative manner, as PEDOT nanopores display three well-defined voltage-controlled transport regimes: cation-rectifying, non-rectifying, and anion rectifying regimes. This work illustrates the potential and versatility of PEDOT as a key enabler to achieve electrochemically addressable solid-state nanopores. The synergism arising from the combination of highly functional conducting polymers and the remarkable physical characteristics of asymmetric nanopores is believed to offer a promising framework to explore new design concepts in nanofluidic devices.The integration of conductive poly(3,4-ethylenedioxythiophene) (PEDOT) into asymmetric solid-state nanopores leads the way to the construction of all-plastic field-effect nanofluidic diodes. The conducting layer acts as a gate electrode by changing its electrochemical state upon the application of different voltages. PEDOT-based electrochemically addressable nanofluidic devices display three well-defined voltage-controlled transport regimes: cation-rectifying, nonrectifying, and anion rectifying regimes.
      PubDate: 2017-05-18T02:02:34.368733-05:
      DOI: 10.1002/adma.201700972
       
  • Regulating Water-Reduction Kinetics in Cobalt Phosphide for Enhancing HER
           Catalytic Activity in Alkaline Solution
    • Authors: Kun Xu; Hui Ding, Mengxing Zhang, Min Chen, Zikai Hao, Lidong Zhang, Changzheng Wu, Yi Xie
      Abstract: Electrochemical water splitting to produce hydrogen renders a promising pathway for renewable energy storage. Considering limited electrocatalysts have good oxygen-evolution reaction (OER) catalytic activity in acid solution while numerous economical materials show excellent OER catalytic performance in alkaline solution, developing new strategies that enhance the alkaline hydrogen-evolution reaction (HER) catalytic activity of cost-effective catalysts is highly desirable for achieving highly efficient overall water splitting. Herein, it is demonstrated that synergistic regulation of water dissociation and optimization of hydrogen adsorption free energy on electrocatalysts can significantly promote alkaline HER catalysis. Using oxygen-incorporated Co2P as an example, the synergistic effect brings about 15-fold enhancement of alkaline HER activity. Theory calculations confirm that the water dissociation free energy of Co2P decreases significantly after oxygen incorporation, and the hydrogen adsorption free energy can also be optimized simultaneously. The finding suggests the powerful effectiveness of synergetic regulation of water dissociation and optimization of hydrogen adsorption free energy on electrocatalysts for alkaline HER catalysis.Developing highly efficient electrocatalysts in an alkaline electrolyte for the hydrogen-evolution reaction (HER) is significant for realizing efficient overall water splitting. The coordinative effect of engineering a water dissociation step and the hydrogen adsorption free energy in Co2P by oxygen incorporation can lead to 15 times enhancement of the HER catalytic activity in alkaline solution. A new strategy for the design of advanced alkaline HER electrocatalysts is thus provided.
      PubDate: 2017-05-17T06:10:35.670406-05:
      DOI: 10.1002/adma.201606980
       
  • Self-Adjusting, Polymeric Multilayered Roll that can Keep the Shapes of
           the Blood Vessel Scaffolds during Biodegradation
    • Authors: Shiyu Cheng; Yu Jin, Nuoxin Wang, Feng Cao, Wei Zhang, Wei Bai, Wenfu Zheng, Xingyu Jiang
      Abstract: A self-adjusting, blood vessel-mimicking, multilayered tubular structure with two polymers, poly(ε-caprolactone) (PCL) and poly(dl-lactide-co-glycolide) (PLGA), can keep the shape of the scaffold during biodegradation. The inner (PCL) layer of the tube can expand whereas the outer (PLGA) layers will shrink to maintain the stability of the shape and the inner space of the tubular shape both in vitro and in vivo over months. This approach can be generally useful for making scaffolds that require the maintenance of a defined shape, based on FDA-approved materials.A method to fabricate a self-adjusting, blood vessel-mimicking, multilayered structure with two polymers, poly(ε-caprolactone) (PCL) and poly(dl-lactide-co-glycolide) (PLGA), by combining electrospinning, stress-induced rolling membrane, and microfluidic techniques is reported. This structure can sustain the geometry of the artificial blood vessel over long periods of in vitro/in vivo culture due to the counteraction and mechanical balance of the PCL/PLGA layers.
      PubDate: 2017-05-17T06:06:34.290214-05:
      DOI: 10.1002/adma.201700171
       
  • Ultrahigh-Conductivity Polymer Hydrogels with Arbitrary Structures
    • Authors: Bowen Yao; Haiyan Wang, Qinqin Zhou, Mingmao Wu, Miao Zhang, Chun Li, Gaoquan Shi
      Abstract: A poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) hydrogel is prepared by thermal treatment of a commercial PEDOT:PSS (PH1000) suspension in 0.1 mol L−1 sulfuric acid followed by partially removing its PSS component with concentrated sulfuric acid. This hydrogel has a low solid content of 4% (by weight) and an extremely high conductivity of 880 S m−1. It can be fabricated into different shapes such as films, fibers, and columns with arbitrary sizes for practical applications. A highly conductive and mechanically strong porous fiber is prepared by drying PEDOT:PSS hydrogel fiber to fabricate a current-collector-free solid-state flexible supercapacitor. This fiber supercapacitor delivers a volumetric capacitance as high as 202 F cm−3 at 0.54 A cm−3 with an extraordinary high-rate performance. It also shows excellent electrochemical stability and high flexibility, promising for the application as wearable energy-storage devices.A poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) hydrogel treated by concentrated sulfuric acid shows an extraordinarily high conductivity of 880 S m−1. It can be fabricated into arbitrary structures for practical applications. A current-collector-free all-solid fiber supercapacitor based on dried fibers of this hydrogel exhibits a performance superior to those of previously reported counterparts.
      PubDate: 2017-05-17T06:05:49.103734-05:
      DOI: 10.1002/adma.201700974
       
  • Imaging Nanoscale Morphology of Semiconducting Polymer Films with
           Photoemission Electron Microscopy
    • Authors: Andreas Neff; Falk Niefind, Bernd Abel, Stefan C. B. Mannsfeld, Katrin R. Siefermann
      Abstract: Photoemission electron microscopy in combination with polarized laser light is presented as a tool permitting direct imaging of polymer-chain orientation and local degree of order in semicrystalline samples of semiconducting polymers, a promising class of materials for future electronics. The key advantages of this imaging tool are its nondestructive and fast measurements, straightforward data analysis, the low complexity of sample preparation, and the possibility of performing measurements on a broad variety of technologically relevant substrates. The high spatial resolution of the microscope provides insights into the nanoscale morphology, which is relevant for the material's performance in electronic devices.Photoemission electron microscopy in combination with polarized laser light is presented as a tool permitting fast imaging of polymer-chain orientation and local degree of order in semicrystalline samples of semiconducting polymers. The high spatial resolution of the microscope provides insights into the nanoscale morphology, which is relevant for the material's performance in electronic devices.
      PubDate: 2017-05-17T06:05:43.088857-05:
      DOI: 10.1002/adma.201701012
       
  • Oxidized Quasi-Carbon Nitride Quantum Dots Inhibit Ice Growth
    • Authors: Guoying Bai; Zhiping Song, Hongya Geng, Dong Gao, Kai Liu, Shuwang Wu, Wei Rao, Liangqia Guo, Jianjun Wang
      Abstract: Antifreeze proteins (AFPs), a type of high-efficiency but expensive and often unstable biological antifreeze, have stimulated substantial interest in the search for synthetic mimics. However, only a few reported AFP mimics display thermal hysteresis, and general criteria for the design of AFP mimics remain unknown. Herein, oxidized quasi-carbon nitride quantum dots (OQCNs) are synthesized through an up-scalable bottom-up approach. They exhibit thermal-hysteresis activity, an ice-crystal shaping effect, and activity on ice-recrystallization inhibition. In the cryopreservation of sheep red blood cells, OQCNs improve cell recovery to more than twice that obtained by using a commercial cryoprotectant (hydroxyethyl starch) without the addition of any organic solvents. It is shown experimentally that OQCNs preferably bind onto the ice-crystal surface, which leads to the inhibition of ice-crystal growth due to the Kelvin effect. Further analysis reveals that the match of the distance between two neighboring tertiary N atoms on OQCNs with the repeated spacing of O atoms along the c-axis on the primary prism plane of ice lattice is critical for OQCNs to bind preferentially on ice crystals. Here, the application of graphitic carbon nitride derivatives for cryopreservation is reported for the first time.Oxidized quasi-carbon nitride quantum dots (OQCNs), which possess the ability to shape ice crystals and inhibit ice growth/recrystallization, are synthesized by a simple and up-scalable approach. In the cryopreservation of sheep red blood cells, OQCNs significantly improve the cell recovery to more than twice that obtained by using a commercial cryoprotectant (hydroxyethyl starch) without the addition of any organic solvents.
      PubDate: 2017-05-17T06:05:38.975214-05:
      DOI: 10.1002/adma.201606843
       
  • Brain-Inspired Photonic Neuromorphic Devices using Photodynamic Amorphous
           Oxide Semiconductors and their Persistent Photoconductivity
    • Authors: Minkyung Lee; Woobin Lee, Seungbeom Choi, Jeong-Wan Jo, Jaekyun Kim, Sung Kyu Park, Yong-Hoon Kim
      Abstract: The combination of a neuromorphic architecture and photonic computing may open up a new era for computational systems owing to the possibility of attaining high bandwidths and the low-computation-power requirements. Here, the demonstration of photonic neuromorphic devices based on amorphous oxide semiconductors (AOSs) that mimic major synaptic functions, such as short-term memory/long-term memory, spike-timing-dependent plasticity, and neural facilitation, is reported. The synaptic functions are successfully emulated using the inherent persistent photoconductivity (PPC) characteristic of AOSs. Systematic analysis of the dynamics of photogenerated carriers for various AOSs is carried out to understand the fundamental mechanisms underlying the photoinduced carrier-generation and relaxation behaviors, and to search for a proper channel material for photonic neuromorphic devices. It is found that the activation energy for the neutralization of ionized oxygen vacancies has a significant influence on the photocarrier-generation and time-variant recovery behaviors of AOSs, affecting the PPC behavior.A brain-inspired photonic neuromorphic device is demonstrated using an amorphous indium-gallium-zinc-oxide film. By utilizing the persistent photoconductivity behavior, short-term memory/long-term memory, spike-timing-dependent plasticity, and neural facilitation are emulated, which are the important synaptic functions for learning and memory. This work may open up new possibilities to realize ultrafast and massive parallel synaptic computing systems based on photonic neuromorphic devices.
      PubDate: 2017-05-17T06:05:30.883221-05:
      DOI: 10.1002/adma.201700951
       
  • A Single-Molecular AND Gate Operated with Two Orthogonal Switching
           Mechanisms
    • Authors: Na Zhang; Wai-Yip Lo, Anex Jose, Zhengxu Cai, Lianwei Li, Luping Yu
      Abstract: Single-molecular electronics is a potential solution to nanoscale electronic devices. While simple functional single-molecule devices such as diodes, switches, and wires are well studied, complex single-molecular systems with multiple functional units are rarely investigated. Here, a single-molecule AND logic gate is constructed from a proton-switchable edge-on gated pyridinoparacyclophane unit with a light-switchable diarylethene unit. The AND gate can be controlled orthogonally by light and protonation and produce desired electrical output at room temperature. The AND gate shows high conductivity when treated with UV light and in the neutral state, and low conductivity when treated either with visible light or acid. A conductance difference of 7.3 is observed for the switching from the highest conducting state to second-highest conducting state and a conductance ratio of 94 is observed between the most and least conducting states. The orthogonality of the two stimuli is further demonstrated by UV–vis, NMR, and density function theory calculations. This is a demonstration of concept of constructing a complex single-molecule electronic device from two coupled functional units.A single-molecule AND gate is constructed from two different switching mechanisms, the switch between conjugation to cross-conjugation by light and the shift of conducting orbitals by protonation. The two switches are orthogonal and can be switched reversibly. The switching ratio between the highest and lowest conductance states is 94.
      PubDate: 2017-05-17T00:30:40.332477-05:
      DOI: 10.1002/adma.201701248
       
  • Defect Chemistry of Nonprecious-Metal Electrocatalysts for Oxygen
           Reactions
    • Authors: Dafeng Yan; Yunxiao Li, Jia Huo, Ru Chen, Liming Dai, Shuangyin Wang
      Abstract: Oxygen electrocatalysis, including the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER), is a critical process for metal–air batteries. Therefore, the development of electrocatalysts for the OER and the ORR is of essential importance. Indeed, various advanced electrocatalysts have been designed for the ORR or the OER; however, the origin of the advanced activity of oxygen electrocatalysts is still somewhat controversial. The enhanced activity is usually attributed to the high surface areas, the unique facet structures, the enhanced conductivities, or even to unclear synergistic effects, but the importance of the defects, especially the intrinsic defects, is often neglected. More recently, the important role of defects in oxygen electrocatalysis has been demonstrated by several groups. To make the defect effect clearer, the recent development of this concept is reviewed here and a novel principle for the design of oxygen electrocatalysts is proposed. An overview of the defects in carbon-based, metal-free electrocatalysts for ORR and various defects in metal oxides/selenides for OER is also provided. The types of defects and controllable strategies to generate defects in electrocatalysts are presented, along with techniques to identify the defects. The defect–activity relationship is also explored by theoretical methods.Defects in carbon-based metal-free electrocatalysts for the oxygen-reduction reaction (ORR) and various defects in metal oxide/selenide for the oxygen-evolution reaction (OER) are reviewed. The existence of defects has a great effect on the properties of catalysts; for example, the charge distribution and the conductibility. The strategies to generate defects, the defect–activity relationship, and the techniques to identify defects are discussed.
      PubDate: 2017-05-16T02:25:59.210825-05:
      DOI: 10.1002/adma.201606459
       
  • Tuning Up or Down the Critical Thickness in LaAlO3/SrTiO3 through In Situ
           Deposition of Metal Overlayers
    • Authors: Diogo Castro Vaz; Edouard Lesne, Anke Sander, Hiroshi Naganuma, Eric Jacquet, Jacobo Santamaria, Agnès Barthélémy, Manuel Bibes
      Abstract: The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 and SrTiO3 has attracted much attention from the oxide electronics community. One of its hallmark features is the existence of a critical LaAlO3 thickness of 4 unit-cells (uc) for interfacial conductivity to emerge. In this paper, the chemical, electronic, and transport properties of LaAlO3/SrTiO3 samples capped with different metals grown in a system combining pulsed laser deposition, sputtering, and in situ X-ray photoemission spectroscopy are investigated. The results show that for metals with low work function a q2DES forms at 1–2 uc of LaAlO3 and is accompanied by a partial oxidation of the metal, a phenomenon that affects the q2DES properties and triggers the formation of defects. In contrast, for noble metals, the critical thickness is increased above 4 uc. The results are discussed in terms of a hybrid mechanism that incorporates electrostatic and chemical effects.The possibility to tune up or down the critical thickness at which a 2D electron gas appears at the LaAlO3/SrTiO3 interface, by capping the LaAlO3 with different metals is demonstrated. Besides electrostatic effects, X-ray photoemission spectroscopy reveals the importance of the partial oxidation of the metal on the properties of the gas.
      PubDate: 2017-05-15T11:50:34.560448-05:
      DOI: 10.1002/adma.201700486
       
  • A Microfluidic Ion Pump for In Vivo Drug Delivery
    • Authors: Ilke Uguz; Christopher M. Proctor, Vincenzo F. Curto, Anna-Maria Pappa, Mary J. Donahue, Magali Ferro, Róisín M. Owens, Dion Khodagholy, Sahika Inal, George G. Malliaras
      Abstract: Implantable devices offer an alternative to systemic delivery of drugs for the treatment of neurological disorders. A microfluidic ion pump (µFIP), capable of delivering a drug without the solvent through electrophoresis, is developed. The device is characterized in vitro by delivering γ-amino butyric acid to a target solution, and demonstrates low-voltage operation, high drug-delivery capacity, and high ON/OFF ratio. It is also demonstrated that the device is suitable for cortical delivery in vivo by manipulating the local ion concentration in an animal model and altering neural behavior. These results show that µFIPs represent a significant step forward toward the development of implantable drug-delivery systems.A microfluidic ion pump is developed, which is capable of delivering a drug without a solvent. In vitro characterization shows low-voltage operation, high drug-delivery capacity, and high ON/OFF ratio. Cortical delivery in an animal model shows that this device represents a significant step forward toward the development of implantable drug-delivery systems.
      PubDate: 2017-05-15T01:20:29.596043-05:
      DOI: 10.1002/adma.201701217
       
  • Photosensitization Priming of Tumor Microenvironments Improves Delivery of
           Nanotherapeutics via Neutrophil Infiltration
    • Authors: Dafeng Chu; Xinyue Dong, Qi Zhao, Jingkai Gu, Zhenjia Wang
      Abstract: Remodeling of tumor microenvironments enables enhanced delivery of nanoparticles (NPs). This study shows that direct priming of a tumor tissue using photosensitization rapidly activates neutrophil infiltration that mediates delivery of nanotherapeutics into the tumor. A drug delivery platform is comprised of NPs coated with anti-CD11b antibodies (Abs) that target activated neutrophils. Intravital microscopy demonstrates that the movement of anti-CD11b Abs-decorated NPs (NPs-CD11b) into the tumor is mediated by neutrophil infiltration induced by photosensitization (PS) because the systemic depletion of neutrophils completely abolishes the nanoparticle tumor deposition. The neutrophil uptake of NPs does not alter neutrophil activation and transmigration. For cancer therapy in mice, tumor PS and photothermal therapy of anti-CD11b Abs-linked gold nanorods (GNRs-CD11b) are combined to treat the carcinoma tumor. The result indicates that neutrophil tumor infiltration enhances nanoparticle cancer therapy. The findings reveal that promoting tumor infiltration of neutrophils by manipulating tumor microenvironments could be a novel strategy to actively deliver nanotherapeutics in cancer therapies.Active delivery of nanotherapeutics to tumor is mediated by neutrophil infiltration after the tumor is photosensitized to induce acute inflammation. Anti-CD11b antibody-decorated nanoparticles are specifically internalized by activated neutrophils in vivo that mediate the tumor deposition of NPs. Photothermal therapy using this approach dramatically improves the cancer treatment in mice.
      PubDate: 2017-05-15T00:45:37.787095-05:
      DOI: 10.1002/adma.201701021
       
  • Ultrahigh Thermal Conductive yet Superflexible Graphene Films
    • Authors: Li Peng; Zhen Xu, Zheng Liu, Yan Guo, Peng Li, Chao Gao
      Abstract: Electrical devices generate heat at work. The heat should be transferred away immediately by a thermal manager to keep proper functions, especially for high-frequency apparatuses. Besides high thermal conductivity (K), the thermal manager material requires good foldability for the next generation flexible electronics. Unfortunately, metals have satisfactory ductility but inferior K (≤429 W m−1 K−1), and highly thermal-conductive nonmetallic materials are generally brittle. Therefore, fabricating a foldable macroscopic material with a prominent K is still under challenge. This study solves the problem by folding atomic thin graphene into microfolds. The debris-free giant graphene sheets endow graphene film (GF) with a high K of 1940 ± 113 W m−1 K−1. Simultaneously, the microfolds render GF superflexible with a high fracture elongation up to 16%, enabling it more than 6000 cycles of ultimate folding. The large-area multifunctional GFs can be easily integrated into high-power flexible devices for highly efficient thermal management.An atomic crystal-folding principle is proposed for designing highly thermal-conductive yet superflexible graphene film. Debris-free, giant graphene sheets and folded atomic thin crystals afford macroscopic assembled graphene film a high thermal conductivity 1940 W m−1 K−1 and fracture elongation 16%, respectively. This principle opens the door for high-performance yet flexible inorganic/ceramic macroscopic materials and devices.
      PubDate: 2017-05-12T07:33:02.829412-05:
      DOI: 10.1002/adma.201700589
       
  • In Situ Probing of Ion Ordering at an Electrified Ionic Liquid/Au
           Interface
    • Authors: Wattaka Sitaputra; Dario Stacchiola, James F. Wishart, Feng Wang, Jerzy T. Sadowski
      Abstract: Charge transport at the interface of electrodes and ionic liquids is critical for the use of the latter as electrolytes. A room-temperature ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide (EMMIM TFSI), is investigated in situ under applied bias voltage with a novel method using low-energy electron and photoemission electron microscopy. Changes in photoelectron yield as a function of bias applied to electrodes provide a direct measure of the dynamics of ion reconfiguration and electrostatic responses of the EMMIM TFSI. Long-range and correlated ionic reconfigurations that occur near the electrodes are found to be a function of temperature and thickness, which, in turn, relate to ionic mobility and different configurations for out-of-plane ordering near the electrode interfaces, with a critical transition in ion mobility for films thicker than three monolayers.Reconfiguration of electric-double-layer ion ordering at electrified ionic liquid/solid interfaces involves complex restructuring of ions. Motion of oppositely charged ions during rearrangement is observed in real time using photoemission electron microscopy. This first step toward novel operando studies of ionic-liquid electrolyte dynamics opens up experimental possibilities for correlating functional properties with local ionic measurements at electrolyte/electrode interfaces.
      PubDate: 2017-05-12T07:31:58.040344-05:
      DOI: 10.1002/adma.201606357
       
  • Superlubricity between MoS2 Monolayers
    • Authors: He Li; Jinhuan Wang, Song Gao, Qing Chen, Lianmao Peng, Kaihui Liu, Xianlong Wei
      Abstract: The ultralow friction between atomic layers of hexagonal MoS2, an important solid lubricant and additive of lubricating oil, is thought to be responsible for its excellent lubricating performances. However, the quantitative frictional properties between MoS2 atomic layers have not been directly tested in experiments due to the lack of conventional tools to characterize the frictional properties between 2D atomic layers. Herein, a versatile method for studying the frictional properties between atomic-layered materials is developed by combining the in situ scanning electron microscope technique with a Si nanowire force sensor, and the friction tests on the sliding between atomic-layered materials down to monolayers are reported. The friction tests on the sliding between incommensurate MoS2 monolayers give a friction coefficient of ≈10−4 in the regime of superlubricity. The results provide the first direct experimental evidence for superlubricity between MoS2 atomic layers and open a new route to investigate frictional properties of broad 2D materials.A method for friction tests between atomic layers of 2D materials is developed based on in situ scanning electron microscope technique. Friction tests on the sliding between MoS2 monolayers give an ultralow friction coefficient of ≈10−4, providing the first direct experimental evidence for the superlubricity between atomic layers of hexagonal MoS2.
      PubDate: 2017-05-12T07:27:43.254881-05:
      DOI: 10.1002/adma.201701474
       
  • Ambient Protection of Few-Layer Black Phosphorus via Sequestration of
           Reactive Oxygen Species
    • Authors: Sumeet Walia; Sivacarendran Balendhran, Taimur Ahmed, Mandeep Singh, Christopher El-Badawi, Mathew D. Brennan, Pabudi Weerathunge, Md. Nurul Karim, Fahmida Rahman, Andrea Rassell, Jonathan Duckworth, Rajesh Ramanathan, Gavin E. Collis, Charlene J. Lobo, Milos Toth, Jimmy Christopher Kotsakidis, Bent Weber, Michael Fuhrer, Jose M. Dominguez-Vera, Michelle J. S. Spencer, Igor Aharonovich, Sharath Sriram, Madhu Bhaskaran, Vipul Bansal
      Abstract: Few-layer black phosphorous (BP) has emerged as a promising candidate for next-generation nanophotonic and nanoelectronic devices. However, rapid ambient degradation of mechanically exfoliated BP poses challenges in its practical deployment in scalable devices. To date, the strategies employed to protect BP have relied upon preventing its exposure to atmospheric conditions. Here, an approach that allows this sensitive material to remain stable without requiring its isolation from the ambient environment is reported. The method draws inspiration from the unique ability of biological systems to avoid photo-oxidative damage caused by reactive oxygen species. Since BP undergoes similar photo-oxidative degradation, imidazolium-based ionic liquids are employed as quenchers of these damaging species on the BP surface. This chemical sequestration strategy allows BP to remain stable for over 13 weeks, while retaining its key electronic characteristics. This study opens opportunities to practically implement BP and other environmentally sensitive 2D materials for electronic applications.Few-layer black phosphorous (BP) has recently emerged as a promising elemental analog to graphene. This study reports a chemical sequestration approach that allows BP to remain stable without requiring its isolation from the ambient environment. The strategy allows BP to remain stable for over 13 weeks, while retaining its key electronic characteristics.
      PubDate: 2017-05-12T07:27:39.297293-05:
      DOI: 10.1002/adma.201700152
       
  • Self-Assembled Au/CdSe Nanocrystal Clusters for Plasmon-Mediated
           Photocatalytic Hydrogen Evolution
    • Authors: Run Shi; Yinhu Cao, Yanjun Bao, Yufei Zhao, Geoffrey I. N. Waterhouse, Zheyu Fang, Li-Zhu Wu, Chen-Ho Tung, Yadong Yin, Tierui Zhang
      Abstract: Plasmon-mediated photocatalytic systems generally suffer from poor efficiency due to weak absorption overlap and thus limited energy transfer between the plasmonic metal and the semiconductor. Herein, a near-ideal plasmon-mediated photocatalyst system is developed. Au/CdSe nanocrystal clusters (NCs) are successfully fabricated through a facile emulsion-based self-assembly approach, containing Au nanoparticles (NPs) of size 2.8, 4.6, 7.2, or 9.0 nm and CdSe quantum dots (QDs) of size ≈3.3 nm. Under visible-light irradiation, the Au/CdSe NCs with 7.2 nm Au NPs afford very stable operation and a remarkable H2-evolution rate of 73  mmol  gCdSe−1 h−1 (10× higher than bare CdSe NCs). Plasmon resonance energy transfer from the Au NPs to the CdSe QDs, which enhances charge-carrier generation in the semiconductor and suppresses bulk recombination, is responsible for the outstanding photocatalytic performance. The approach used here to fabricate the Au/CdSe NCs is suitable for the construction of other plasmon-mediated photocatalysts.Highly efficient plasmon-mediated photocatalysts based on Au/CdSe nanocrystal clusters (NCs) are successfully fabricated through an emulsion-based self-assembly approach. The Au/CdSe NCs synergistically harness the excellent visible-light-absorption properties of CdSe quantum dots and Au nanoparticles, affording a remarkable H2 evolution rate of 73 mmol gCdSe−1 h−1 in aqueous solution under visible-light illumination and excellent operational stability.
      PubDate: 2017-05-12T07:27:30.43463-05:0
      DOI: 10.1002/adma.201700803
       
  • Laser-Induced Graphene in Controlled Atmospheres: From Superhydrophilic to
           Superhydrophobic Surfaces
    • Authors: Yilun Li; Duy Xuan Luong, Jibo Zhang, Yash R. Tarkunde, Carter Kittrell, Franklin Sargunaraj, Yongsung Ji, Christopher J. Arnusch, James M. Tour
      Abstract: The modification of graphene-based materials is an important topic in the field of materials research. This study aims to expand the range of properties for laser-induced graphene (LIG), specifically to tune the hydrophobicity and hydrophilicity of the LIG surfaces. While LIG is normally prepared in the air, here, using selected gas atmospheres, a large change in the water contact angle on the as-prepared LIG surfaces has been observed, from 0° (superhydrophilic) when using O2 or air, to>150° (superhydrophobic) when using Ar or H2. Characterization of the newly derived surfaces shows that the different wetting properties are due to the surface morphology and chemical composition of the LIG. Applications of the superhydrophobic LIG are shown in oil/water separation as well as anti-icing surfaces, while the versatility of the controlled atmosphere chamber fabrication method is demonstrated through the improved microsupercapacitor performance generated from LIG films prepared in an O2 atmosphere.The modification of graphene-based materials has been an important topic, and this study aims to expand the properties of laser-induced graphene (LIG). With a controlled atmosphere chamber, both superhydrophobic and superhydrophilic LIG surfaces can be obtained. Characterizations show that the different wetting properties result from surface morphology and chemical composition. Applications are demonstrated in oil/water separation, anti-icing, as well as microsupercapacitors.
      PubDate: 2017-05-12T07:27:22.020884-05:
      DOI: 10.1002/adma.201700496
       
  • Semiconducting Nanowire-Based Optoelectronic Fibers
    • Authors: Wei Yan; Yunpeng Qu, Tapajyoti Das Gupta, Arouna Darga, Dang Tùng Nguyên, Alexis Gérald Page, Mariana Rossi, Michele Ceriotti, Fabien Sorin
      Abstract: The recent ability to integrate semiconductor-based optoelectronic functionalities within thin fibers is opening intriguing opportunities for flexible electronics and advanced textiles. The scalable integration of high-quality semiconducting devices within functional fibers however remains a challenge. It is difficult with current strategies to combine high light absorption, good microstructure and efficient electrical contact. The growth of semiconducting nanowires is a great tool to control crystal orientation and ensure a combination of light absorption and charge extraction for efficient photodetection. Thus far, however, leveraging the attributes of nanowires has remained seemingly incompatible with fiber materials, geometry, and processing approaches. Here, the integration of semiconducting nanowire-based devices at the tip and along the length of polymer fibers is demonstrated for the first time. The scalable thermal drawing process is combined with a simple sonochemical treatment to grow nanowires out of electrically addressed amorphous selenium domains. First principles density-functional theory calculations show that this approach enables to tailor the surface energy of crystal facets and favors nanowire growth along a preferred orientation, resulting in fiber-integrated devices of unprecedented performance. This novel platform is exploited to demonstrate an all-fiber-integrated fluorescence imaging system, highlighting novel opportunities in sensing, advanced optical probes, and smart textiles.High-quality monocrystalline semiconducting nanowire-based optoelectronic devices, for the first time, are integrated into the tip of a polymer optical fiber and along the fiber length. The fiber-integrated devices, fabricated via a combination of simple and scalable approaches, exhibit unprecedented optoelectronic properties. The opportunities of this approach in advanced fibers and textiles are highlighted via an all-fiber-integrated fluorescence imaging system.
      PubDate: 2017-05-12T07:26:46.453315-05:
      DOI: 10.1002/adma.201700681
       
  • Optical, Thermal, and Mechanical Characterization of Ga2Se3-Added GLS
           Glass
    • Authors: Andrea Ravagli; Christopher Craig, Ghada A. Alzaidy, Paul Bastock, Daniel W. Hewak
      Abstract: Gallium lanthanum sulfide glass (GLS) has been widely studied in the last 40 years for middle-infrared applications. In this work, the results of the substitution of selenium for sulphur in GLS glass are described. The samples are prepared via melt-quench method in an argon-purged atmosphere. A wide range of compositional substitutions are studied to define the glass-forming region of the modified material. The complete substitution of Ga2S3 by Ga2Se3 is achieved by involving new higher quenching rate techniques compared to those containing only sulfides. The samples exhibiting glassy characteristics are further characterized. In particular, the optical and thermal properties of the sample are investigated in order to understand the role of selenium in the formation of the glass. The addition of selenium to GLS glass generally results in a lower glass transition temperature and an extended transmission window. Particularly, the IR edge is found to be extended from about 9 µm for GLS glass to about 15 µm for Se-added GLS glass defined by the 50% transmission point. Furthermore, the addition of selenium does not affect the UV edge dramatically. The role of selenium is hypothesized in the glass formation to explain these changes.Theresults of the addition of Se to gallium lanthanum sulfide(GLS) glass through the substitution of Ga2S3 by Ga2Se3 are described. An innovative open melting apparatus is used. The addition of selenium to GLS glass generally results in a lower glass transition temperature and an extended transmission window up to 15 µm with minor effect on the visible transmission.
      PubDate: 2017-05-11T01:46:31.250468-05:
      DOI: 10.1002/adma.201606329
       
  • Vertically Aligned Niobium Nanowire Arrays for Fast-Charging
           Micro-Supercapacitors
    • Authors: Seyed M. Mirvakili; Ian W. Hunter
      Abstract: Planar micro-supercapacitors are attractive for system on chip technologies and surface mount devices due to their large areal capacitance and energy/power density compared to the traditional oxide-based capacitors. In the present work, a novel material, niobium nanowires, in form of vertically aligned electrodes for application in high performance planar micro-supercapacitors is introduced. Specific capacitance of up to 1 kF m−2 (100 mF cm−2) with peak energy and power density of 2 kJ m−2 (6.2 MJ m−3 or 1.7 mWh cm−3) and 150 kW m−2 (480 MW m−3 or 480 W cm−3), respectively, is achieved. This remarkable power density, originating from the extremely low equivalent series resistance value of 0.27 Ω (2.49 µΩ m2 or 24.9 mΩ cm2) and large specific capacitance, is among the highest for planar micro-supercapacitors electrodes made of nanomaterials.Fast-charging micro-supercapacitors are made from vertically aligned niobium nanowire arrays. Thanks to the high electrical conductivity of the nanowires, the micro-supercapacitor exhibits a very small characteristic relaxation time constant of 8.4 ms. With 1 m sulfuric acid, cycling rates of up to 300 V s−1 are achieved while with 1-ethyl-3-methylimidazolium tetrafluoroborate an operating voltage of up to 4 V is obtained.
      PubDate: 2017-05-11T01:40:30.65479-05:0
      DOI: 10.1002/adma.201700671
       
  • Optochemically Responsive 2D Nanosheets of a 3D Metal–Organic
           Framework Material
    • Authors: Abhijeet K. Chaudhari; Ha Jin Kim, Intaek Han, Jin-Chong Tan
      Abstract: Outstanding functional tunability underpinning metal–organic framework (MOF) confers a versatile platform to contrive next-generation chemical sensors, optoelectronics, energy harvesters, and converters. A rare exemplar of a porous 2D nanosheet material constructed from an extended 3D MOF structure is reported. A rapid supramolecular self-assembly methodology at ambient conditions to synthesize readily exfoliatable MOF nanosheets, functionalized in situ by adopting the guest@MOF (host) strategy, is developed. Nanoscale confinement of light-emitting molecules (as functional guest) inside the MOF pores generates unusual combination of optical, electronic, and chemical properties, arising from the strong host–guest coupling effects. Highly promising photonics-based chemical sensing opened up by the new guest@MOF composite systems is shown. By harnessing host–guest optochemical interactions of functionalized MOF nanosheets, detection of an extensive range of volatile organic compounds and small molecules important for many practical applications has been accomplished.A rapid supramolecular method to synthesize the “OX-1” (Oxford University-1) nanosheet metal–organic framework (MOF), functionalized adopting the guest@MOF strategy, is reported. Nanoscale confinement of light-emitting guest molecules in the OX-1 pores yields remarkable optical, electronic, and chemical properties. Harnessing reversible host–guest interactions, photochemical sensing of volatile organic compounds and small molecules important for many practical applications is demonstrated.
      PubDate: 2017-05-10T06:16:25.564924-05:
      DOI: 10.1002/adma.201701463
       
  • Recent Progress in the Design of Advanced Cathode Materials and Battery
           Models for High-Performance Lithium-X (X = O2, S, Se, Te, I2, Br2)
           Batteries
    • Authors: Jiantie Xu; Jianmin Ma, Qinghua Fan, Shaojun Guo, Shixue Dou
      Abstract: Recent advances and achievements in emerging Li-X (X = O2, S, Se, Te, I2, Br2) batteries with promising cathode materials open up new opportunities for the development of high-performance lithium-ion battery alternatives. In this review, we focus on an overview of recent important progress in the design of advanced cathode materials and battery models for developing high-performance Li-X (X = O2, S, Se, Te, I2, Br2) batteries. We start with a brief introduction to explain why Li-X batteries are important for future renewable energy devices. Then, we summarize the existing drawbacks, major progress and emerging challenges in the development of cathode materials for Li-O2 (S) batteries. In terms of the emerging Li-X (Se, Te, I2, Br2) batteries, we systematically summarize their advantages/disadvantages and recent progress. Specifically, we review the electrochemical performance of Li-Se (Te) batteries using carbonate-/ether-based electrolytes, made with different electrode fabrication techniques, and of Li-I2 (Br2) batteries with various cell designs (e.g., dual electrolyte, all-organic electrolyte, with/without cathode-flow mode, and fuel cell/solar cell integration). Finally, the perspective on and challenges for the development of cathode materials for the promising Li-X (X = O2, S, Se, Te, I2, Br2) batteries is presented.Emerging Li-X (X = O2, S, Se, Te, I2, Br2) batteries with promising cathode materials open up new opportunities for the development of high-performance lithium-ion battery alternatives. Here, an overview of recent important progress in the design of advanced cathode materials and battery models for developing high-performance Li-X batteries is presented.
      PubDate: 2017-05-10T06:16:16.996339-05:
      DOI: 10.1002/adma.201606454
       
  • Large Modulation of Charge Carrier Mobility in Doped Nanoporous Organic
           Transistors
    • Authors: Fengjiao Zhang; Xiaojuan Dai, Weikun Zhu, Hyunjoong Chung, Ying Diao
      Abstract: Molecular doping of organic electronics has shown promise to sensitively modulate important device metrics. One critical challenge is the disruption of structure order upon doping of highly crystalline organic semiconductors, which significantly reduces the charge carrier mobility. This paper demonstrates a new method to achieve large modulation of charge carrier mobility via channel doping without disrupting the molecular ordering. Central to the method is the introduction of nanopores into the organic semiconductor thin films via a simple and robust templated meniscus-guided coating method. Using this method, the charge carrier mobility of C8-benzothieno[3,2-b]benzothiophene transistors is boosted by almost sevenfold. This paper further demonstrates enhanced electron transport by close to an order of magnitude in a diketopyrrolopyrrole-based donor–acceptor polymer. Combining spectroscopic measurements, density functional theory calculations, and electrical characterizations, the doping mechanism is identified as partial-charge-transfer induced trap filling. The nanopores serve to enhance the dopant/organic semiconductor charge transfer reaction by exposing the π-electrons to the pore wall.Doping of organic electronics without disrupting molecular packing is a critical challenge preventing effective modulation of charge transport properties. This paper reports on enhanced charge-transfer doping in crystalline small molecule and polymer transistors by introducing nanopores in organic semiconductors via meniscus-guided coating. Nanopores lead to dramatic increase in charge carrier mobility by promoting charge transfer reaction across the pore wall.
      PubDate: 2017-05-10T06:15:46.603626-05:
      DOI: 10.1002/adma.201700411
       
  • Solvent-Free Self-Assembly to the Synthesis of Nitrogen-Doped Ordered
           Mesoporous Polymers for Highly Selective Capture and Conversion of CO2
    • Authors: Fujian Liu; Kuan Huang, Qin Wu, Sheng Dai
      Abstract: A solvent-free induced self-assembly technology for the synthesis of nitrogen-doped ordered mesoporous polymers (N-OMPs) is developed, which is realized by mixing polymer precursors with block copolymer templates, curing at 140–180 °C, and calcination to remove the templates. This synthetic strategy represents a significant advancement in the preparation of functional porous polymers through a fast and scalable yet environmentally friendly route, since no solvents or catalysts are used. The synthesized N-OMPs and their derived catalysts are found to exhibit competitive CO2 capacities (0.67–0.91 mmol g−1 at 25 °C and 0.15 bar), extraordinary CO2/N2 selectivities (98–205 at 25 °C), and excellent activities for catalyzing conversion of CO2 into cyclic carbonate (conversion>95% at 100 °C and 1.2 MPa for 1.5 h). The solvent-free technology developed in this work can also be extended to the synthesis of N-OMP/SiO2 nanocomposites, mesoporous SiO2, crystalline mesoporous TiO2, and TiPO, demonstrating its wide applicability in porous material synthesis.A novel and green strategy in which no solvents are used, for the fast synthesis of nitrogen-doped ordered mesoporous polymers (N-OMPs) is developed. The N-OMPs display competitive CO2 capacities and extraordinary CO2/N2 selectivities, as well as excellent activity for catalytic conversion of CO2. The methodology can also be extended to the synthesis of N-OMP/SiO2 nanocomposites, mesoporous SiO2, TiO2, and TiPO.
      PubDate: 2017-05-10T06:15:41.433186-05:
      DOI: 10.1002/adma.201700445
       
  • Pseudohalide-Exchanged Quantum Dot Solids Achieve Record Quantum
           Efficiency in Infrared Photovoltaics
    • Authors: Bin Sun; Oleksandr Voznyy, Hairen Tan, Philipp Stadler, Mengxia Liu, Grant Walters, Andrew H. Proppe, Min Liu, James Fan, Taotao Zhuang, Jie Li, Mingyang Wei, Jixian Xu, Younghoon Kim, Sjoerd Hoogland, Edward H. Sargent
      Abstract: Application of pseudohalogens in colloidal quantum dot (CQD) solar-cell active layers increases the solar-cell performance by reducing the trap densities and implementing thick CQD films. Pseudohalogens are polyatomic analogs of halogens, whose chemistry allows them to substitute halogen atoms by strong chemical interactions with the CQD surfaces. The pseudohalide thiocyanate anion is used to achieve a hybrid surface passivation. A fourfold reduced trap state density than in a control is observed by using a suite of field-effect transistor studies. This translates directly into the thickest CQD active layer ever reported, enabled by enhanced transport lengths in this new class of materials, and leads to the highest external quantum efficiency, 80% at the excitonic peak, compared with previous reports of CQD solar cells.Pseudohalogens in solar cells are applied and the performance is increased by reducing trap densities and implementing thick colloidal quantum dot (CQD) films. The pseudohalide-exchanged CQD films have four times lower trap state density than the controls, as seen in field-effect transistor (FET) studies. This results in an external quantum efficiency of 80% at the infrared excitonic peak, the highest reported in CQD photovoltaics.
      PubDate: 2017-05-10T06:15:35.613322-05:
      DOI: 10.1002/adma.201700749
       
  • Electrostatic Design of 3D Covalent Organic Networks
    • Authors: Veronika Obersteiner; Andreas Jeindl, Johannes Götz, Aurelie Perveaux, Oliver T. Hofmann, Egbert Zojer
      Abstract: An innovative strategy for electrostatically designing the electronic structure of 3D bulk materials is proposed to control charge carriers at the nanoscale. This is achieved by shifting the electronic levels of chemically identical semiconducting elements through the periodic arrangement of polar functional groups. For the example of covalent organic networks, by first-principles calculations, the resulting collective electrostatic effects are shown to allow a targeted manipulation of the electronic landscape such that spatially confined pathways for electrons and holes can be realized. Mimicking donor–acceptor bulk heterojunctions, the new materials hold high promise for photovoltaic applications. The distinct advantage over the conventional approach of splitting excitons through chemically distinct donor and acceptor units is that here the magnitude of the band offset can be continuously tuned by varying the dipole density. A particularly promising feature of the suggested strategy is its structural versatility, which also enables the realization of more complex quantum structures such as quantum-cascades and quantum-checkerboards.The electrostatic design of 3D covalent organic networks is presented as an innovative strategy to mimic donor–acceptor heterojunctions. Periodic arrangements of polar building blocks are used to locally shift the energies of electronic states and to spatially confine frontier wavefunctions. In this way, a driving force for exciton dissociation is realized without the need for using distinct semiconducting units.
      PubDate: 2017-05-10T06:05:49.661988-05:
      DOI: 10.1002/adma.201700888
       
  • Metamorphic Superomniphobic Surfaces
    • Authors: Wei Wang; Joshua Salazar, Hamed Vahabi, Alexandra Joshi-Imre, Walter E. Voit, Arun K. Kota
      Abstract: Superomniphobic surfaces are extremely repellent to virtually all liquids. By combining superomniphobicity and shape memory effect, metamorphic superomniphobic (MorphS) surfaces that transform their morphology in response to heat are developed. Utilizing the MorphS surfaces, the distinctly different wetting transitions of liquids with different surface tensions are demonstrated and the underlying physics is elucidated. Both ex situ and in situ wetting transitions on the MorphS surfaces are solely due to transformations in morphology of the surface texture. It is envisioned that the robust MorphS surfaces with reversible wetting transition will have a wide range of applications including rewritable liquid patterns, controlled drug release systems, lab-on-a-chip devices, and biosensors.Metamorphic superomniphobic surfaces with a thermoresponsive shape memory polymer are fabricated, the distinctly different wetting transitions of liquids with different surface tensions are demonstrated, and the underlying physics is elucidated.
      PubDate: 2017-05-09T06:06:35.691694-05:
      DOI: 10.1002/adma.201700295
       
  • Materials Nanoarchitecturing via Cation-Mediated Protein Assembly: Making
           Limpet Teeth without Mineral
    • Authors: Tina Ukmar-Godec; Luca Bertinetti, John W. C. Dunlop, Aljaž Godec, Michal A. Grabiger, Admir Masic, Huynh Nguyen, Igor Zlotnikov, Paul Zaslansky, Damien Faivre
      Abstract: Teeth are designed to deliver high forces while withstanding the generated stresses. Aside from isolated mineral-free exception (e.g., marine polychaetes and squids), minerals are thought to be indispensable for tooth-hardening and durability. Here, the unmineralized teeth of the giant keyhole limpet (Megathura crenulata) are shown to attain a stiffness, which is twofold higher than any known organic biogenic structures. In these teeth, protein and chitin fibers establish a stiff compact outer shell enclosing a less compact core. The stiffness and its gradients emerge from a concerted interaction across multiple length-scales: packing of hydrophobic proteins and folding into secondary structures mediated by Ca2+ and Mg2+ together with a strong spatial control in the local fiber orientation. These results integrating nanoindentation, acoustic microscopy, and finite-element modeling for probing the tooth's mechanical properties, spatially resolved small- and wide-angle X-ray scattering for probing the material ordering on the micrometer scale, and energy-dispersive X-ray scattering combined with confocal Raman microscopy to study structural features on the molecular scale, reveal a nanocomposite structure hierarchically assembled to form a versatile damage-tolerant protein-based tooth, with a stiffness similar to mineralized mammalian bone, but without any mineral.The teeth of the giant keyhole limpet (Megathura crenulata) are unmineralized but exhibit a stiffness, which is twofold higher than any known organic biogenic structures. This study reveals the structure–function relationship of a unique biological material.
      PubDate: 2017-05-09T01:16:10.445241-05:
      DOI: 10.1002/adma.201701171
       
  • A Synaptic Transistor based on Quasi-2D Molybdenum Oxide
    • Authors: Chuan Sen Yang; Da Shan Shang, Nan Liu, Gang Shi, Xi Shen, Ri Cheng Yu, Yong Qing Li, Young Sun
      Abstract: Biological synapses store and process information simultaneously by tuning the connection between two neighboring neurons. Such functionality inspires the task of hardware implementation of neuromorphic computing systems. Ionic/electronic hybrid three-terminal memristive devices, in which the channel conductance can be modulated according to the history of applied voltage and current, provide a more promising way of emulating synapses by a substantial reduction in complexity and energy consumption. 2D van der Waals materials with single or few layers of crystal unit cells have been a widespread innovation in three-terminal electronic devices. However, less attention has been paid to 2D transition-metal oxides, which have good stability and technique compatibility. Here, nanoscale three-terminal memristive transistors based on quasi-2D α-phase molybdenum oxide (α-MoO3) to emulate biological synapses are presented. The essential synaptic behaviors, such as excitatory postsynaptic current, depression and potentiation of synaptic weight, and paired-pulse facilitation, as well as the transition of short-term plasticity to long-term potentiation, are demonstrated in the three-terminal devices. These results provide an insight into the potential application of 2D transition-metal oxides for synaptic devices with high scaling ability, low energy consumption, and high processing efficiency.A quasi-2D transition-metal oxide, α-phase molybdenum oxide (α-MoO3), is used to fabricate nanoscale three-terminal memristive transistors. The essential biological synaptic behaviors, such as excitatory postsynaptic current, depression and potentiation of synaptic weight, paired-pulse facilitation, and the transition of short-term plasticity to long-term potentiation, are demonstrated in the three-terminal devices.
      PubDate: 2017-05-09T01:15:58.242044-05:
      DOI: 10.1002/adma.201700906
       
  • Ink-Free Reversible Optical Writing in Monolayers by Polymerization of a
           Trifunctional Monomer: Toward Rewritable “Molecular Paper”
    • Authors: Vivian Müller; Tim Hungerland, Milos Baljozovic, Thomas Jung, Nicholas D. Spencer, Hadi Eghlidi, Payam Payamyar, A. Dieter Schlüter
      Abstract: A Langmuir–Blodgett film consisting of a dense array of trifunctional monomers bearing three 1,8-diazaanthracene units is polymerized at an air/water interface or after transfer on solid substrates. The transfer does not affect the excimer fluorescence of the film, indicating that the monomers' packing with their diazaanthracene units stacked face-to-face is retained—a prerequisite for successful polymerization. The monomer film can be polymerized in confined areas on solid substrates by UV irradiation with a confocal microscope laser. The underlying chemistry of the polymerization, a [4+4]-cycloaddition of the diazaanthracene units, leads to disappearance of the fluorescence in the irradiated regions which enables writing into the monolayer on a µm scale—thus the term “molecular paper.” The reaction can be reversed by heating which leads to a recovery of the fluorescence and to erasing of the writing. Alternative pathways for this phenomenon are discussed and control experiments are conducted to rule them out.“Molecular paper”—a nanometer thin, fluorescent film which can be depositedon various substrates and written onto by irradiation with a confocal microscope laser. Irradiation leads to disappearance of the fluorescence in the targeted area, allowing writing on a micrometer scale. This process is reversible by heating which recovers the film's fluorescence and “erases” the writing.
      PubDate: 2017-05-09T01:15:49.494715-05:
      DOI: 10.1002/adma.201701220
       
  • Indium-Free Perovskite Solar Cells Enabled by Impermeable Tin-Oxide
           Electron Extraction Layers
    • Authors: Ting Hu; Tim Becker, Neda Pourdavoud, Jie Zhao, Kai Oliver Brinkmann, Ralf Heiderhoff, Tobias Gahlmann, Zengqi Huang, Selina Olthof, Klaus Meerholz, Daniel Többens, Baochang Cheng, Yiwang Chen, Thomas Riedl
      Abstract: Corrosive precursors used for the preparation of organic–inorganic hybrid perovskite photoactive layers prevent the application of ultrathin metal layers as semitransparent bottom electrodes in perovskite solar cells (PVSCs). This study introduces tin-oxide (SnOx) grown by atomic layer deposition (ALD), whose outstanding permeation barrier properties enable the design of an indium-tin-oxide (ITO)-free semitransparent bottom electrode (SnOx/Ag or Cu/SnOx), in which the metal is efficiently protected against corrosion. Simultaneously, SnOx functions as an electron extraction layer. We unravel the spontaneous formation of a PbI2 interfacial layer between SnOx and the CH3NH3PbI3 perovskite. An interface dipole between SnOx and this PbI2 layer is found, which depends on the oxidant (water, ozone, or oxygen plasma) used for the ALD growth of SnOx. An electron extraction barrier between perovskite and PbI2 is identified, which is the lowest in devices based on SnOx grown with ozone. The resulting PVSCs are hysteresis-free with a stable power conversion efficiency (PCE) of 15.3% and a remarkably high open circuit voltage of 1.17 V. The ITO-free analogues still achieve a high PCE of 11%.Corrosive precursors used to prepare organo-metal-halide perovskite photoactive layers usually prevent the application of ultrathin metal layers in semitransparent bottom electrodes. Tin-oxide/metal/tin-oxide electrode is introduced, where the ultrathin metal layer is shielded by impermeable tin-oxide (SnOx) grown by atomic layer deposition. The SnOx concomitantly functions as an electron extraction layer that affords a high open circuit voltage of 1.17 V.
      PubDate: 2017-05-08T07:25:56.848046-05:
      DOI: 10.1002/adma.201606656
       
  • Substrate Doping Effect and Unusually Large Angle van Hove Singularity
           Evolution in Twisted Bi- and Multilayer Graphene
    • Authors: Han Peng; Niels B. M. Schröter, Jianbo Yin, Huan Wang, Ting-Fung Chung, Haifeng Yang, Sandy Ekahana, Zhongkai Liu, Juan Jiang, Lexian Yang, Teng Zhang, Cheng Chen, Heng Ni, Alexey Barinov, Yong P. Chen, Zhongfan Liu, Hailin Peng, Yulin Chen
      Abstract: Graphene has demonstrated great potential in new-generation electronic applications due to its unique electronic properties such as large carrier Fermi velocity, ultrahigh carrier mobility, and high material stability. Interestingly, the electronic structures can be further engineered in multilayer graphene by the introduction of a twist angle between different layers to create van Hove singularities (vHSs) at adjustable binding energy. In this work, using angle-resolved photoemission spectroscopy with sub-micrometer spatial resolution, the band structures and their evolution are systematically studied with twist angle in bilayer and trilayer graphene sheets. A doping effect is directly observed in graphene multilayer system as well as vHSs in bilayer graphene over a wide range of twist angles (from 5° to 31°) with wide tunable energy range over 2 eV. In addition, the formation of multiple vHSs (at different binding energies) is also observed in trilayer graphene. The large tuning range of vHS binding energy in twisted multilayer graphene provides a promising material base for optoelectrical applications with broadband wavelength selectivity from the infrared to the ultraviolet regime, as demonstrated by an example application of wavelength selective photodetector.Tuning the twist angle in twisted bilayer graphene provides an intriguing route to engineer graphene's band structure for optoelectronic applications. In this work, interlayer coupling over a wide twist angle range (5°–31°) is reported, which leads to van Hove singularities with energy separation up to 2 eV. Furthermore, the doping of multilayer graphene by copper substrate is investigated in detail.
      PubDate: 2017-05-08T07:25:48.342977-05:
      DOI: 10.1002/adma.201606741
       
  • Large Magnetovolume Effect Induced by Embedding Ferromagnetic Clusters
           into Antiferromagnetic Matrix of Cobaltite Perovskite
    • Authors: Ping Miao; Xiaohuan Lin, Akihiro Koda, Sanghyun Lee, Yoshihisa Ishikawa, Shuki Torii, Masao Yonemura, Takashi Mochiku, Hajime Sagayama, Shinichi Itoh, Kazutaka Ikeda, Toshiya Otomo, Yinxia Wang, Ryosuke Kadono, Takashi Kamiyama
      Abstract: Materials that show negative thermal expansion (NTE) have significant industrial merit because they can be used to fabricate composites whose dimensions remain invariant upon heating. In some materials, NTE is concomitant with the spontaneous magnetization due to the magnetovolume effect (MVE). Here the authors report a new class of MVE material; namely, a layered perovskite PrBaCo2O5.5+x (0 ≤ x ≤ 0.41), in which strong NTE [β ≈ −3.6 × 10−5 K−1 (90–110 K) at x = 0.24] is triggered by embedding ferromagnetic (F) clusters into the antiferromagnetic (AF) matrix. The strongest MVE is found near the boundary between F and AF phases in the phase diagram, indicating the essential role of competition between the F-clusters and the AF-matrix. Furthermore, the MVE is not limited to the PrBaCo2O5.5+x but is also observed in the NdBaCo2O5.5+x. The present study provides a new approach to obtaining MVE and offers a path to the design of NTE materials.A new class of negative thermal expansion (NTE) material is discovered, in which the NTE is induced by a new mechanism. Namely, the layered perovskite PrBaCo2O5.5+x (0 ≤ x ≤ 0.41) exhibits a strong NTE when embedding (F) clusters into the (AF) matrix, where the competition between the F and AF phases plays the essential role.
      PubDate: 2017-05-08T07:25:33.730916-05:
      DOI: 10.1002/adma.201605991
       
  • Enhanced Solar-to-Hydrogen Generation with Broadband Epsilon-Near-Zero
           Nanostructured Photocatalysts
    • Authors: Yi Tian; Francisco Pelayo García de Arquer, Cao-Thang Dinh, Gael Favraud, Marcella Bonifazi, Jun Li, Min Liu, Xixiang Zhang, Xueli Zheng, Md. Golam Kibria, Sjoerd Hoogland, David Sinton, Edward H. Sargent, Andrea Fratalocchi
      Abstract: The direct conversion of solar energy into fuels or feedstock is an attractive approach to address increasing demand of renewable energy sources. Photocatalytic systems relying on the direct photoexcitation of metals have been explored to this end, a strategy that exploits the decay of plasmonic resonances into hot carriers. An efficient hot carrier generation and collection requires, ideally, their generation to be enclosed within few tens of nanometers at the metal interface, but it is challenging to achieve this across the broadband solar spectrum. Here the authors demonstrate a new photocatalyst for hydrogen evolution based on metal epsilon-near-zero metamaterials. The authors have designed these to achieve broadband strong light confinement at the metal interface across the entire solar spectrum. Using electron energy loss spectroscopy, the authors prove that hot carriers are generated in a broadband fashion within 10 nm in this system. The resulting photocatalyst achieves a hydrogen production rate of 9.5 µmol h−1 cm−2 that exceeds, by a factor of 3.2, that of the best previously reported plasmonic-based photocatalysts for the dissociation of H2 with 50 h stable operation.A new scalable photocatalyst heterostructure based on a complex epsilon near zero nanoplasmonic material is designed and characterized. The resulting photocatalyst exhibits a stable production rate of hydrogen production of 9.5 µmol h−1 cm−2. This performance exceeds, by a factor of 3.2, that of the best previously reported plasmonic-based photocatalysts for the dissociation of H2 from water.
      PubDate: 2017-05-08T07:20:51.719433-05:
      DOI: 10.1002/adma.201701165
       
  • Stepwise Crosslinking: A Facile Yet Versatile Conceptual Strategy to
           Nanomorphology-Persistent Porous Organic Polymers
    • Authors: Hao Liu; Shimei Li, Hongyu Yang, Shaohong Liu, Luyi Chen, Zhiwei Tang, Ruowen Fu, Dingcai Wu
      Abstract: Both high surface areas and well-orchestrated nanomorphologies are important for porous organic polymers (POPs). However, the two key characteristics are generally difficult to be satisfied simultaneously, because the common pore-making procedures usually produce ill-defined nanomorphologies or give rise to damage of precustomized nanomorphologies. Herein, a facile yet versatile stepwise crosslinking strategy for fabrication of POPs with an unusual nanomorphology-persistent characteristic during pore-making is reported. Polystyrene nanofibers and poly(styrene-co-divinylbenzene) nanosphere arrays are utilized as building blocks, and then transformed into nanofibrillar morphology-persistent and ordered array morphology-persistent POPs via stepwise crosslinking, respectively. The stepwise crosslinking strategy includes pre-crosslinking and hypercrosslinking; the pre-crosslinking in a carefully selected poor solvent of polystyrene forms a lowly crosslinked structure, which guarantees the stability of nanomorphology during the subsequent pore-making via hypercrosslinking. The as-obtained POPs can be used as precursors for novel well-defined hyperporous carbon nanofibers and ordered carbon nanosphere arrays with excellent adsorption performances.Both high surface areas and well-orchestrated morphologies are important but generally difficult to be satisfied simultaneously for porous organic polymers (POPs). Herein, a facile yet versatile stepwise crosslinking strategy for fabrication of POPs with an unusual nanomorphology-persistent characteristic during pore-making is reported. The as-obtained POPs are utilized as precursors for novel well-defined hyperporous carbon nanofibers and ordered carbon nanosphere arrays.
      PubDate: 2017-05-08T07:20:40.775212-05:
      DOI: 10.1002/adma.201700723
       
  • Origami-Based Reconfigurable Metamaterials for Tunable Chirality
    • Authors: Zuojia Wang; Liqiao Jing, Kan Yao, Yihao Yang, Bin Zheng, Costas M. Soukoulis, Hongsheng Chen, Yongmin Liu
      Abstract: Origami is the art of folding two-dimensional (2D) materials, such as a flat sheet of paper, into complex and elaborate three-dimensional (3D) objects. This study reports origami-based metamaterials whose electromagnetic responses are dynamically controllable via switching the folding state of Miura-ori split-ring resonators. The deformation of the Miura-ori unit along the third dimension induces net electric and magnetic dipoles of split-ring resonators parallel or anti-parallel to each other, leading to the strong chiral responses. Circular dichroism as high as 0.6 is experimentally observed while the chirality switching is realized by controlling the deformation direction and kinematics. In addition, the relative density of the origami metamaterials can be dramatically reduced to only 2% of that of the unfolded structure. These results open a new avenue toward lightweight, reconfigurable, and deployable metadevices with simultaneously customized electromagnetic and mechanical properties.An approach toward reconfigurable metamaterials with simultaneously customized electromagnetic and mechanical properties is presented. Strong chiroptical responses are induced when transforming a planar, achiral metasurface into 3D origami metamaterials, and breaking the mirror symmetry of the folded origami metamaterials. The relative density of the origami metamaterials can be dramatically reduced to only 2% of that of the unfolded structure.
      PubDate: 2017-05-08T07:20:32.282093-05:
      DOI: 10.1002/adma.201700412
       
  • Transferable Organic Semiconductor Nanosheets for Application in
           Electronic Devices
    • Authors: Simon J. Noever; Michael Eder, Fabio del Giudice, Jan Martin, Franz X. Werkmeister, Stefan Hallwig, Stefan Fischer, Oliver Seeck, Nils-Eike Weber, Clemens Liewald, Fritz Keilmann, Andrey Turchanin, Bert Nickel
      Abstract: A method has been developed to stabilize and transfer nanofilms of functional organic semiconductors. The method is based on crosslinking of their topmost layers by low energy electron irradiation. The films can then be detached from their original substrates and subsequently deposited onto new solid or holey substrates retaining their structural integrity. Grazing incidence X-ray diffraction, X-ray specular reflectivity, and UV–Vis spectroscopy measurements reveal that the electron irradiation of ≈50 nm thick pentacene films results in crosslinking of their only topmost ≈5 nm (3–4 monolayers), whereas the deeper pentacene layers preserve their pristine crystallinity. The electronic performance of the transferred pentacene nanosheets in bottom contact field-effect devices is studied and it is found that they are fully functional and demonstrate superior charge injection properties in comparison to the pentacene films directly grown on the contact structures by vapor deposition. The new approach paves the way to integration of the organic semiconductor nanofilms on substrates unfavorable for their direct growth as well as to their implementation in hybrid devices with unusual geometries, e.g., in devices incorporating free-standing sheets.The surface of highly ordered organic semiconductor thin films is cross-linked by low energy electron beam irradiation. Irradiated films can be detached and transferred to other substrates including free standing geometries. The electronic properties of the organic thin films are preserved. Here, improved injection properties for transferred films in bottom contact field-effect transistors are demonstrated.
      PubDate: 2017-05-08T02:00:02.963027-05:
      DOI: 10.1002/adma.201606283
       
  • 3D Printed Stretchable Tactile Sensors
    • Authors: Shuang-Zhuang Guo; Kaiyan Qiu, Fanben Meng, Sung Hyun Park, Michael C. McAlpine
      Abstract: The development of methods for the 3D printing of multifunctional devices could impact areas ranging from wearable electronics and energy harvesting devices to smart prosthetics and human–machine interfaces. Recently, the development of stretchable electronic devices has accelerated, concomitant with advances in functional materials and fabrication processes. In particular, novel strategies have been developed to enable the intimate biointegration of wearable electronic devices with human skin in ways that bypass the mechanical and thermal restrictions of traditional microfabrication technologies. Here, a multimaterial, multiscale, and multifunctional 3D printing approach is employed to fabricate 3D tactile sensors under ambient conditions conformally onto freeform surfaces. The customized sensor is demonstrated with the capabilities of detecting and differentiating human movements, including pulse monitoring and finger motions. The custom 3D printing of functional materials and devices opens new routes for the biointegration of various sensors in wearable electronics systems, and toward advanced bionic skin applications.A multifunctional three-dimensional (3D) printing approach is employed to fabricate 3D tactile sensors under ambient conditions conformally onto freeform surfaces. The sensors can detect and differente human motions, including pulse monitoring and finger movements. This custom 3D printing of functional materials and devices opens new routes toward the biointegration of various sensors in wearable electronic systems.
      PubDate: 2017-05-05T06:54:43.611418-05:
      DOI: 10.1002/adma.201701218
       
  • One-Pot Synthesis of Multiple Protein-Encapsulated DNA Flowers and Their
           Application in Intracellular Protein Delivery
    • Authors: Eunjung Kim; Limor Zwi-Dantsis, Natalie Reznikov, Catherine S. Hansel, Shweta Agarwal, Molly M. Stevens
      Abstract: Inspired by biological systems, many biomimetic methods suggest fabrication of functional materials with unique physicochemical properties. Such methods frequently generate organic–inorganic composites that feature highly ordered hierarchical structures with intriguing properties, distinct from their individual components. A striking example is that of DNA–inorganic hybrid micro/nanostructures, fabricated by the rolling circle technique. Here, a novel concept for the encapsulation of bioactive proteins in DNA flowers (DNF) while maintaining the activity of protein payloads is reported. A wide range of proteins, including enzymes, can be simultaneously associated with the growing DNA strands and Mg2PPi crystals during the rolling circle process, ultimately leading to the direct immobilization of proteins into DNF. The unique porous structure of this construct, along with the abundance of Mg ions and DNA molecules present, provides many interaction sites for proteins, enabling high loading efficiency and enhanced stability. Further, as a proof of concept, it is demonstrated that the DNF can deliver payloads of cytotoxic protein (i.e., RNase A) to the cells without a loss in its biological function and structural integrity, resulting in highly increased cell death compared to the free protein.Encapsulation of various bioactive proteins in DNA constructs is realized at physiological conditions by a biomimetic crystallization approach, based on the nucleation and growth of Mg2PPi crystals with organic additives such as proteins and DNA. This method offers highly simple and efficient protein loading while retaining the biological functionality of the payloads, opening up a new strategy for protein-based therapeutics.
      PubDate: 2017-05-05T06:54:29.524231-05:
      DOI: 10.1002/adma.201701086
       
  • In Situ Observation of Single-Phase Lithium Intercalation in Sub-25-nm
           Nanoparticles
    • Authors: Li Zhong; Yang Liu, Wei-Qiang Han, Jian Yu Huang, Scott X. Mao
      Abstract: Many lithium-storage materials operate via first-order phase transformations with slow kinetics largely restricted by the nucleation and growth of a new phase. Due to the energy penalties associated with interfaces between coexisting phases, the tendency for a single-phase solid-solution pathway with exceptional reaction kinetics has been predicted to increase with decreasing particle size. Unfortunately, phase evolutions inside such small particles (tens of nanometers) are often shrouded by electrode-scale inhomogeneous reactions containing millions of particles, leading to intensive debate over the size-dependent microscopic reaction mechanisms. This study provides a generally applicable methodology capable of tracking lithiation pathways in individual nanoparticles and unambiguously reveals that lithiation of anatase TiO2, previously long believed to be biphasic, converts to a single-phase reaction when particle size reaches ≈25 nm. These results imply the prevalence of such a size-dependent transition in lithiation mechanism among intercalation compounds and provide important guidelines for designing high-power electrodes, especially cathodes.An unexpected single-phase solid-solution lithiation pathway is directly revealed in sub-25-nm anatase TiO2 nanoparticles by tracking the electron diffraction pattern of individual particles in a multiparticle system, which demonstrates much faster kinetics compared to that in a two-phase reaction. These results imply the prevalence of a size-dependent transition in the reaction pathway among electrode materials exhibiting poor two-phase reaction kinetics.
      PubDate: 2017-05-05T06:54:10.234712-05:
      DOI: 10.1002/adma.201700236
       
  • Light-Responsive Hierarchically Structured Liquid Crystal Polymer Networks
           for Harnessing Cell Adhesion and Migration
    • Authors: Gülistan Koçer; Jeroen ter Schiphorst, Matthew Hendrikx, Hailu G. Kassa, Philippe Leclère, Albertus P. H. J. Schenning, Pascal Jonkheijm
      Abstract: Extracellular microenvironment is highly dynamic where spatiotemporal regulation of cell-instructive cues such as matrix topography tightly regulates cellular behavior. Recapitulating dynamic changes in stimuli-responsive materials has become an important strategy in regenerative medicine to generate biomaterials which closely mimic the natural microenvironment. Here, light responsive liquid crystal polymer networks are used for their adaptive and programmable nature to form hybrid surfaces presenting micrometer scale topographical cues and changes in nanoscale roughness at the same time to direct cell migration. This study shows that the cell speed and migration patterns are strongly dependent on the height of the (light-responsive) micrometer scale topographies and differences in surface nanoroughness. Furthermore, switching cell migration patterns upon in situ temporal changes in surface nanoroughness, points out the ability to dynamically control cell behavior on these surfaces. Finally, the possibility is shown to form photoswitchable topographies, appealing for future studies where topographies can be rendered reversible on demand.Light responsive (dynamic) interfaces on liquid crystal polymer networks present a new way to encode the surface topography of a biomaterial. Photoisomerization of azobenzene molecule conjugated in the network leads to changes in the order of the liquid crystal molecules resulting in volume changes in the illuminated areas, generating predesigned responsive topographical features in order to instruct cell behavior.
      PubDate: 2017-05-05T06:53:25.698203-05:
      DOI: 10.1002/adma.201606407
       
  • Modifying Commercial Carbon with Trace Amounts of ZIF to Prepare
           Derivatives with Superior ORR Activities
    • Authors: Bing Ni; Chen Ouyang, Xiaobin Xu, Jing Zhuang, Xun Wang
      Abstract: Reducing costs while maintaining high activities and stabilities of oxygen reduction reaction (ORR) catalysts has long been pursued for applications to membrane fuel cells. Here, an absorption-reaction method is used to prepare a zeolitic imidazolate framework coated commercial carbon, and the pyrolysis of such material brings about impressive ORR activities and stabilities with large diffusion-limited current density, half-wave potential, and no obvious decay after 10 000 cyclic voltammetry cycles, which is even better than that of the commercial Pt/C catalysts. The absorption-reaction method is realized by simply soaking the commercial carbon black sequentially in Co(NO3)2 and 2-methylimidazole solutions at ambient conditions. The detailed analysis on such carbon materials reveals that both Co and N are essential to activities, even the amount of N and Co species is very low. The reduction of raw materials and simplified handling procedures result in well-controlled costs in applications.Sequentially soaking in Co(NO3)2 and 2-methylimidazole solutions, followed by calcination, can impart high oxygen reduction reaction activities and stabilities to commercial carbon black. The detailed analysis on such carbon materials reveals that both Co and N are essential to activities, even the amount of N and Co species is very low.
      PubDate: 2017-05-04T06:45:52.311668-05:
      DOI: 10.1002/adma.201701354
       
  • Active Phase Transition via Loss Engineering in a Terahertz MEMS
           Metamaterial
    • Authors: Longqing Cong; Prakash Pitchappa, Chengkuo Lee, Ranjan Singh
      Abstract: Controlling the phase of local radiation by using exotic metasurfaces has enabled promising applications in a diversified set of electromagnetic wave manipulation such as anomalous wavefront deflection, flat lenses, and holograms. Here, we theoretically and experimentally demonstrate an active phase transition in a micro-electromechanical system-based metadevice where both the phase response and the dispersion of the metamaterial cavity are dynamically tailored. The phase transition is determined by the radiative and the absorptive losses in a metal–insulator–metal cavity that obeys the coupled-mode theory. The complete understanding of the phase diagram in a reconfigurable configuration would open up avenues for designing multifunctional metadevices that can be actively switched between different phases leading to a plethora of applications in polarization control, beam deflectors, and holographic metamaterials.An active phase transition based on a terahertz micro-electromechanical system metamaterial is experimentally demonstrated where the radiative and nonradiative loss channels are manipulated to switch the resonant operation between underdamped and overdamped states. Several applications can be enabled by controlling the phase response with the complete understanding of the phase diagram in reconfigurable metamaterials.
      PubDate: 2017-05-04T06:45:44.550276-05:
      DOI: 10.1002/adma.201700733
       
  • 3D-Printed, All-in-One Evaporator for High-Efficiency Solar Steam
           Generation under 1 Sun Illumination
    • Authors: Yiju Li; Tingting Gao, Zhi Yang, Chaoji Chen, Wei Luo, Jianwei Song, Emily Hitz, Chao Jia, Yubing Zhou, Boyang Liu, Bao Yang, Liangbing Hu
      Abstract: Using solar energy to generate steam is a clean and sustainable approach to addressing the issue of water shortage. The current challenge for solar steam generation is to develop easy-to-manufacture and scalable methods which can convert solar irradiation into exploitable thermal energy with high efficiency. Although various material and structure designs have been reported, high efficiency in solar steam generation usually can be achieved only at concentrated solar illumination. For the first time, 3D printing to construct an all-in-one evaporator with a concave structure for high-efficiency solar steam generation under 1 sun illumination is used. The solar-steam-generation device has a high porosity (97.3%) and efficient broadband solar absorption (>97%). The 3D-printed porous evaporator with intrinsic low thermal conductivity enables heat localization and effectively alleviates thermal dissipation to the bulk water. As a result, the 3D-printed evaporator has a high solar steam efficiency of 85.6% under 1 sun illumination (1 kW m−2), which is among the best compared with other reported evaporators. The all-in-one structure design using the advanced 3D printing fabrication technique offers a new approach to solar energy harvesting for high-efficiency steam generation.An all-in-one solar steam generator with a concave structure (3D-CG/GN) is prepared by using layer-by-layer 3D printing fabrication. High solar absorption, fast water transport, and excellent heat localization enable a high solar energy conversion efficiency of 85.6% under 1 sun illumination, which is among the best compared with other reported evaporators.
      PubDate: 2017-05-04T06:40:36.526833-05:
      DOI: 10.1002/adma.201700981
       
  • Controllable Fabrication of Au Nanocups by Confined-Space Thermal
           Dewetting for OCT Imaging
    • Authors: Aiqin Gao; Wenjing Xu, Yenisey Ponce de León, Yaocai Bai, Mingfu Gong, Kongliang Xie, Boris Hyle Park, Yadong Yin
      Abstract: Here, this study reports a novel confined-space thermal dewetting strategy for the fabrication of Au nanocups with tunable diameter, height, and size of cup opening. The nanocup morphology is defined by the cup-shaped void space created by a yolk–shell silica template that spontaneously takes an eccentric configuration during annealing. Thermal dewetting of Au, which is sandwiched between the yolk and shell, leads to the desired nanocup morphology. With strong scattering in near infrared, the Au nanocups exhibit superior efficiency as contrast agents for spectral-domain optical coherence tomography imaging. This confined-space thermal dewetting strategy is scalable and general, and can be potentially extended to the synthesis of novel anisotropic nanostructures of various compositions that are difficult to produce by conventional wet chemical or physical methods, thus opening up opportunities for many new applications.A novel confined-space thermal dewetting strategy has been developed for the fabrication of Au nanocups with well-controlled morphologies. With tunable plasmon resonance in the near infrared region, the Au nanocups exhibit superior efficiency as contrast agents in spectral-domain optical coherence tomography imaging.
      PubDate: 2017-05-03T07:10:41.52273-05:0
      DOI: 10.1002/adma.201701070
       
  • In Situ Transformation of MOFs into Layered Double Hydroxide Embedded
           Metal Sulfides for Improved Electrocatalytic and Supercapacitive
           Performance
    • Authors: Gamze Yilmaz; Kah Meng Yam, Chun Zhang, Hong Jin Fan, Ghim Wei Ho
      Abstract: Direct adoption of metal-organic frameworks (MOFs) as electrode materials shows impoverished electrochemical performance owing to low electrical conductivity and poor chemical stability. In this study, we demonstrate self-templated pseudomorphic transformation of MOF into surface chemistry rich hollow framework that delivers highly reactive, durable, and universal electrochemically active energy conversion and storage functionalities. In situ pseudomorphic transformation of MOF-derived hollow rhombic dodecahedron template and sulfurization of nickel cobalt layered double hydroxides (NiCo-LDHs) lead to the construction of interlayered metal sulfides (NiCo-LDH/Co9S8) system. The embedment of metal sulfide species (Co9S8) at the LDH intergalleries offers optimal interfacing of the hybrid constituent elements and materials stability. The hybrid NiCo-LDH/Co9S8 system collectively presents an ideal porous structure, rich redox chemistry, and high electrical conductivity matrix. This leads to a significant enhancement in its complementary electrocatalytic hydrogen evolution and supercapacitive energy storage properties. This work establishes the potential of MOF derived scaffold for designing of novel class hybrid inorganic–organic functional materials for electrochemical applications and beyond.In-situ pseudomorphic transformation strategy is established via facile zeolitic imidazole framework derived templated growth and sulfurization of nickel cobalt layered double hydroxides (NiCo-LDH) to form hybrid hydroxide-sulfide system. The hybrid system synchronously realizes an ideal porous framework, rich redox chemistry, and high electrical conductivity matrix. This leads to a significant enhancement in its complementary electrocatalytic H2 generation and supercapacitive energy storage properties.
      PubDate: 2017-05-03T06:15:43.935844-05:
      DOI: 10.1002/adma.201606814
       
  • Two Well-Miscible Acceptors Work as One for Efficient Fullerene-Free
           Organic Solar Cells
    • Authors: Runnan Yu; Shaoqing Zhang, Huifeng Yao, Bing Guo, Sunsun Li, Hao Zhang, Maojie Zhang, Jianhui Hou
      Abstract: High-performance ternary organic solar cells are fabricated by using a wide-bandgap polymer donor (bithienyl-benzodithiophene-alt-fluorobenzotriazole copolymer, J52) and two well-miscible nonfullerene acceptors, methyl-modified nonfullerene acceptor (IT-M) and 2,2′-((2Z,2′Z)-((5,5′-(4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydros-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IEICO). The two acceptors with complementary absorption spectra and similar lowest unoccupied molecular orbital levels show excellent compatibility in the blend due to their very similar chemical structures. Consequently, the obtained ternary organic solar cells (OSC) exhibits a high efficiency of 11.1%, with an enhanced short-circuit current density of 19.7 mA cm−2 and a fill factor of 0.668. In this ternary system, broadened absorption, similar output voltages, and compatible morphology are achieved simultaneously, demonstrating a promising strategy to further improve the performance of ternary OSCs.Ternary organic solar cells show over 11% power conversion efficiency by using two compatible nonfullerene acceptors with complementary absorption spectra, similar chemical structures, and similar lowest unoccupied molecular orbital levels. Broadened absorption, similar output voltages, and compatible morphology are achieved simultaneously, demonstrating a promising strategy to improve the performance of OSCs.
      PubDate: 2017-05-03T06:15:34.191204-05:
      DOI: 10.1002/adma.201700437
       
  • Improved Performance of All-Polymer Solar Cells Enabled by
           Naphthodiperylenetetraimide-Based Polymer Acceptor
    • Authors: Yikun Guo; Yunke Li, Omar Awartani, Han Han, Jingbo Zhao, Harald Ade, He Yan, Dahui Zhao
      Abstract: A new polymer acceptor, naphthodiperylenetetraimide-vinylene (NDP-V), featuring a backbone of altenating naphthodiperylenetetraimide and vinylene units is designed and applied in all-polymer solar cells (all-PSCs). With this polymer acceptor, a new record power-conversion efficiencies (PCE) of 8.59% has been achieved for all-PSCs. The design principle of NDP-V is to reduce the conformational disorder in the backbone of a previously developed high-performance acceptor, PDI-V, a perylenediimide-vinylene polymer. The chemical modifications result in favorable changes to the molecular packing behaviors of the acceptor and improved morphology of the donor–acceptor (PTB7-Th:NDP-V) blend, which is evidenced by the enhanced hole and electron transport abilities of the active layer. Moreover, the stronger absorption of NDP-V in the shorter-wavelength range offers a better complement to the donor. All these factors contribute to a short-circuit current density (Jsc) of 17.07 mA cm−2. With a fill factor (FF) of 0.67, an average PCE of 8.48% is obtained, representing the highest value thus far reported for all-PSCs.A new polymer acceptor NDP-V is designed and applied in all-polymer solar cells (all-PSCs). With this polymer acceptor, a new record power conversion efficiency of 8.59% has been achieved for all-PSCs, with an open-circuit voltage (Voc) of 0.74 V, a short-circuit current density (Jsc) of 17.07 mA cm−2, and a high fill factor (FF) of 0.67.
      PubDate: 2017-05-03T06:15:29.465715-05:
      DOI: 10.1002/adma.201700309
       
  • Homogeneous/Inhomogeneous-Structured Dielectrics and their Energy-Storage
           Performances
    • Authors: Zhonghua Yao; Zhe Song, Hua Hao, Zhiyong Yu, Minghe Cao, Shujun Zhang, Michael T. Lanagan, Hanxing Liu
      Abstract: The demand for dielectric capacitors with higher energy-storage capability is increasing for power electronic devices due to the rapid development of electronic industry. Existing dielectrics for high-energy-storage capacitors and potential new capacitor technologies are reviewed toward realizing these goals. Various dielectric materials with desirable permittivity and dielectric breakdown strength potentially meeting the device requirements are discussed. However, some significant limitations for current dielectrics can be ascribed to their low permittivity, low breakdown strength, and high hysteresis loss, which will decrease their energy density and efficiency. Thus, the implementation of dielectric materials for high-energy-density applications requires the comprehensive understanding of both the materials design and processing. The optimization of high-energy-storage dielectrics will have far-reaching impacts on the sustainable energy and will be an important research topic in the near future.Recent innovative strategies in advanced materials for high-energy-storage capacitors are highlighted. A range of diverse approaches and materials design to elevate energy-storage performances by dielectric breakdown, permittivity, polarization behavior, and hysteresis loss, etc. is intensively discussed. The perspectives and current limitation of these emerging dielectrics for high-energy-storage capacitors and potential new capacitor technologies toward realizing goals are also addressed.
      PubDate: 2017-02-23T02:30:37.401642-05:
      DOI: 10.1002/adma.201601727
       
  • Effect of the Microstructure of the Functional Layers on the Efficiency of
           Perovskite Solar Cells
    • Authors: Fuzhi Huang; Alexander R. Pascoe, Wu-Qiang Wu, Zhiliang Ku, Yong Peng, Jie Zhong, Rachel A. Caruso, Yi-Bing Cheng
      Abstract: The efficiencies of the hybrid organic–inorganic perovskite solar cells have been rapidly approaching the benchmarks held by the leading thin-film photovoltaic technologies. Arguably, one of the most important factors leading to this rapid advancement is the ability to manipulate the microstructure of the perovskite layer and the adjacent functional layers within the device. Here, an analysis of the nucleation and growth models relevant to the formation of perovskite films is provided, along with the effect of the perovskite microstructure (grain sizes and voids) on device performance. In addition, the effect of a compact or mesoporous electron-transport-layer (ETL) microstructure on the perovskite film formation and the optical/photoelectric properties at the ETL/perovskite interface are overviewed. Insight into the formation of the functional layers within a perovskite solar cell is provided, and potential avenues for further development of the perovskite microstructure are identified.The performance of perovskite solar cells is greatly affected by the microstructure of the functional layers, especially that of the perovskite film. By controlling the nucleation and crystal growth process, desirable microstructures (grains and voids size) of the perovskite films, such as dense films with large grains, can be achieved for high-efficiency solar cells.
      PubDate: 2017-02-22T07:45:34.225228-05:
      DOI: 10.1002/adma.201601715
       
  • Heterojunction Photocatalysts
    • Authors: Jingxiang Low; Jiaguo Yu, Mietek Jaroniec, Swelm Wageh, Ahmed A. Al-Ghamdi
      Abstract: Semiconductor-based photocatalysis attracts wide attention because of its ability to directly utilize solar energy for production of solar fuels, such as hydrogen and hydrocarbon fuels and for degradation of various pollutants. However, the efficiency of photocatalytic reactions remains low due to the fast electron–hole recombination and low light utilization. Therefore, enormous efforts have been undertaken to solve these problems. Particularly, properly engineered heterojunction photocatalysts are shown to be able to possess higher photocatalytic activity because of spatial separation of photogenerated electron–hole pairs. Here, the basic principles of various heterojunction photocatalysts are systematically discussed. Recent efforts toward the development of heterojunction photocatalysts for various photocatalytic applications are also presented and appraised. Finally, a brief summary and perspectives on the challenges and future directions in the area of heterojunction photocatalysts are also provided.Heterojunction photocatalysts attract a lot of attention because of their effectiveness for spatial separation of photogenerated electron–hole pairs. Therefore, various types of heterojunction photocatalyst are applied in different photocatalytic fields, including H2 production, CO2 reduction, and pollutant degradation. The development of heterojunction photocatalysts can lead to significant advancements in the photocatalysis field.
      PubDate: 2017-02-21T07:42:08.920132-05:
      DOI: 10.1002/adma.201601694
       
  • NASICON-Structured Materials for Energy Storage
    • Authors: Zelang Jian; Yong-Sheng Hu, Xiulei Ji, Wen Chen
      Abstract: The demand for electrical energy storage (EES) is ever increasing, which calls for better batteries. NASICON-structured materials represent a family of important electrodes due to its superior ionic conductivity and stable structures. A wide range of materials have been considered, where both vanadium-based and titanium-based materials are recommended as being of great interest. NASICON-structured materials are suitable for both the cathode and the anode, where the operation potential can be easily tuned by the choice of transition metal and/or polyanion group in the structure. NASICON-structured materials also represent a class of solid electrolytes, which are widely employed in all-solid-state ion batteries, all-solid-state air batteries, and hybrid batteries. NASICON-structured materials are reviewed with a focus on both electrode materials and solid-state electrolytes.NASICON-structured materials exhibit great structural stability and fast ionic conductivity. More importantly, these materials can be used as cathodes, anodes, and solid electrolytes. In general, the interfacial resistance between a solid electrolyte and the electrodes in solid-state batteries is large. However, if all-NASICON solid-state batteries can be fabricated, the interfacial resistance may be decreased because it can form a solid-solution or composite between electrodes and electrolytes due to their similar structure.
      PubDate: 2017-02-21T07:26:57.317134-05:
      DOI: 10.1002/adma.201601925
       
  • Conjugated-Polymer Blends for Organic Photovoltaics: Rational Control of
           Vertical Stratification for High Performance
    • Authors: Yu Yan; Xuan Liu, Tao Wang
      Abstract: The photoactive layer of bulk-heterojunction organic solar cells, in a thickness range of tens to hundreds of nanometers, comprises phase-separated electron donors and acceptors after solution casting. The component distribution in the cross-section of these thin films is found to be heterogeneous, with electron donors or acceptors accumulated or depleted near the electrode interfaces. This vertical stratification of the photovoltaic blend influences device metrics through its impact on charge transport and recombination, and consequently plays an important role in determining the power conversion efficiency of photovoltaic devices. Here, different techniques, e.g., surface analysis and sputter-assisted depth-profiling, reflectivity modeling, and 3D imaging, that have been employed to characterize vertical stratification in bulk-heterojunction photovoltaic blends are reviewed. The origins of vertical stratification are summarized, including thermodynamics, kinetics, surface free energy, and selective dissolubility. The impact of correct and wrong vertical stratification to device metrics of solar cells are highlighted. Examples are then given to demonstrate how desired vertical stratification can be controlled with properly aligned device architecture to enable solar cells with high efficiency.Vertical stratification of the electron donor and acceptor components in bulk-heterojunction photovoltaic blends can happen during their film-formation process after solution casting and the subsequent post-treatment process, and can significantly influence device efficiency of organic solar cells through its impact on the effective charge transport and collection.
      PubDate: 2017-02-13T07:31:40.893459-05:
      DOI: 10.1002/adma.201601674
       
  • Intricate Hollow Structures: Controlled Synthesis and Applications in
           Energy Storage and Conversion
    • Authors: Liang Zhou; Zechao Zhuang, Huihui Zhao, Mengting Lin, Dongyuan Zhao, Liqiang Mai
      Abstract: Intricate hollow structures garner tremendous interest due to their aesthetic beauty, unique structural features, fascinating physicochemical properties, and widespread applications. Here, the recent advances in the controlled synthesis are discussed, as well as applications of intricate hollow structures with regard to energy storage and conversion. The synthetic strategies toward complex multishelled hollow structures are classified into six categories, including well-established hard- and soft-templating methods, as well as newly emerging approaches based on selective etching of “soft@hard” particles, Ostwald ripening, ion exchange, and thermally induced mass relocation. Strategies for constructing structures beyond multishelled hollow structures, such as bubble-within-bubble, tube-in-tube, and wire-in-tube structures, are also covered. Niche applications of intricate hollow structures in lithium-ion batteries, Li–S batteries, supercapacitors, Li–O2 batteries, dye-sensitized solar cells, photocatalysis, and fuel cells are discussed in detail. Some perspectives on the future research and development of intricate hollow structures are also provided.Intricate hollow structures attract tremendous interest due to their aesthetic beauty, unique structural features, fascinating physicochemical properties, and widespread applications. A comprehensive overview on the controlled synthesis of intricate hollow structures is given, along with their niche applications in secondary batteries, supercapacitors, dye-sensitized solar cells, photocatalysis, and fuel cells.
      PubDate: 2017-02-07T08:00:51.238622-05:
      DOI: 10.1002/adma.201602914
       
  • Nanostructured Metal Oxides and Sulfides for Lithium–Sulfur
           Batteries
    • Authors: Xue Liu; Jia-Qi Huang, Qiang Zhang, Liqiang Mai
      Abstract: Lithium–sulfur (Li–S) batteries with high energy density and long cycle life are considered to be one of the most promising next-generation energy-storage systems beyond routine lithium-ion batteries. Various approaches have been proposed to break down technical barriers in Li–S battery systems. The use of nanostructured metal oxides and sulfides for high sulfur utilization and long life span of Li–S batteries is reviewed here. The relationships between the intrinsic properties of metal oxide/sulfide hosts and electrochemical performances of Li–S batteries are discussed. Nanostructured metal oxides/sulfides hosts used in solid sulfur cathodes, separators/interlayers, lithium-metal-anode protection, and lithium polysulfides batteries are discussed respectively. Prospects for the future developments of Li–S batteries with nanostructured metal oxides/sulfides are also discussed.Nanostructured metal oxides and sulfides are considered as polysulfide anchoring sites in working Li–S batteries for the battery's high sulfur utilization and long life span. The relationships between the intrinsic properties of the metal oxide/sulfide hosts and the electrochemical performances of Li–S batteries are reviewed.
      PubDate: 2017-02-03T17:20:48.924445-05:
      DOI: 10.1002/adma.201601759
       
  • Multi-Scale Microstructural Thermoelectric Materials: Transport Behavior,
           Non-Equilibrium Preparation, and Applications
    • Authors: Xianli Su; Ping Wei, Han Li, Wei Liu, Yonggao Yan, Peng Li, Chuqi Su, Changjun Xie, Wenyu Zhao, Pengcheng Zhai, Qingjie Zhang, Xinfeng Tang, Ctirad Uher
      Abstract: Considering only about one third of the world's energy consumption is effectively utilized for functional uses, and the remaining is dissipated as waste heat, thermoelectric (TE) materials, which offer a direct and clean thermal-to-electric conversion pathway, have generated a tremendous worldwide interest. The last two decades have witnessed a remarkable development in TE materials. This Review summarizes the efforts devoted to the study of non-equilibrium synthesis of TE materials with multi-scale structures, their transport behavior, and areas of applications. Studies that work towards the ultimate goal of developing highly efficient TE materials possessing multi-scale architectures are highlighted, encompassing the optimization of TE performance via engineering the structures with different dimensional aspects spanning from the atomic and molecular scales, to nanometer sizes, and to the mesoscale. In consideration of the practical applications of high-performance TE materials, the non-equilibrium approaches offer a fast and controllable fabrication of multi-scale microstructures, and their scale up to industrial-size manufacturing is emphasized here. Finally, the design of two integrated power generating TE systems are described—a solar thermoelectric-photovoltaic hybrid system and a vehicle waste heat harvesting system—that represent perhaps the most important applications of thermoelectricity in the energy conversion area.Recent progress on optimization of thermoelectric performance via the engineering of structures with different dimensional aspects is reviewed, spanning from the atomic and molecular scale, to nanometer sizes, and to the mesoscale, which can be achieved through non-equilibrium fast and controllable synthesis. Moreover, the design of two integrated thermoelectric power-generating systems are described—a solar thermoelectric–photovoltaic hybrid system and a vehicle waste-heat-harvesting system.
      PubDate: 2017-01-23T08:50:40.070298-05:
      DOI: 10.1002/adma.201602013
       
  • New Opportunities and Challenges of Smart Polymers in Post-Translational
           Modification Proteomics
    • Authors: Guangyan Qing; Qi Lu, Yuting Xiong, Lei Zhang, Hongxi Wang, Xiuling Li, Xinmiao Liang, Taolei Sun
      Abstract: Protein post-translational modifications (PTMs), which denote covalent additions of various functional groups (e.g., phosphate, glycan, methyl, or ubiquitin) to proteins, significantly increase protein complexity and diversity. PTMs play crucial roles in the regulation of protein functions and numerous cellular processes. However, in a living organism, native PTM proteins are typically present at substoichiometric levels, considerably impeding mass-spectrometry-based analyses and identification. Over the past decade, the demand for in-depth PTM proteomics studies has spawned a variety of selective affinity materials capable of capturing trace amounts of PTM peptides from highly complex biosamples. However, novel design ideas or strategies are urgently required for fulfilling the increasingly complex and accurate requirements of PTM proteomics analysis, which can hardly be met by using conventional enrichment materials. Considering two typical types of protein PTMs, phosphorylation and glycosylation, an overview of polymeric enrichment materials is provided here, with an emphasis on the superiority of smart-polymer-based materials that can function in intelligent modes. Moreover, some smart separation materials are introduced to demonstrate the enticing prospects and the challenges of smart polymers applied in PTM proteomics.Protein post-translational modifications (PTMs) greatly increase protein complexity and dynamics and regulate a series of biological processes. However, protein PTM studies are severely hampered by the lack of highly efficient enrichment materials capable of capturing trace amounts of PTM peptides from highly complex biosamples. Utilizing reversible conformational transition of polymer chains in response to the binding of PTM peptides, smart polymers provide novel solutions to tackle these enrichment challenges.
      PubDate: 2017-01-23T08:46:25.40447-05:0
      DOI: 10.1002/adma.201604670
       
  • Porous One-Dimensional Nanomaterials: Design, Fabrication and Applications
           in Electrochemical Energy Storage
    • Authors: Qiulong Wei; Fangyu Xiong, Shuangshuang Tan, Lei Huang, Esther H. Lan, Bruce Dunn, Liqiang Mai
      Abstract: Electrochemical energy storage technology is of critical importance for portable electronics, transportation and large-scale energy storage systems. There is a growing demand for energy storage devices with high energy and high power densities, long-term stability, safety and low cost. To achieve these requirements, novel design structures and high performance electrode materials are needed. Porous 1D nanomaterials which combine the advantages of 1D nanoarchitectures and porous structures have had a significant impact in the field of electrochemical energy storage. This review presents an overview of porous 1D nanostructure research, from the synthesis by bottom-up and top-down approaches with rational and controllable structures, to several important electrochemical energy storage applications including lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, lithium-oxygen batteries and supercapacitors. Highlights of porous 1D nanostructures are described throughout the review and directions for future research in the field are discussed at the end.Porous 1D nanomaterials utilize the advantages of both 1D nanoarchitecture and porous morphology to further enhance the performance of materials for energy-storage applications. The current status of porous 1D nanostructures, from methodologies for rational and controllable synthesis, to their successful application in lithium-ion batteries, sodium-ion batteries, lithium–sulfur batteries, lithium–oxygen batteries and supercapacitors is presented.
      PubDate: 2017-01-20T06:21:30.361947-05:
      DOI: 10.1002/adma.201602300
       
  • Melt-Quenched Hybrid Glasses from Metal–Organic Frameworks
    • Authors: Haizheng Tao; Thomas D. Bennett, Yuanzheng Yue
      Abstract: While glasses formed by quenching the molten states of inorganic non-metallic, organic, and metallic species are known, those containing both inorganic and organic moieties are far less prevalent. Network materials consisting of inorganic nodes linked by organic ligands do however exist in the crystalline or amorphous domain. This large family of open framework compounds, called metal–organic frameworks (MOFs) or coordination polymers, has been investigated intensively in the past two decades for a variety of applications, almost all of which stem from their high internal surface areas and chemical versatility. Recently, a selection of MOFs has been demonstrated to undergo melting and vitrification upon cooling. Here, these recent discoveries and the connections between the fields of MOF chemistry and glass science are summarized. Possible advantages and applications for MOF glasses produced by utilizing the tunable chemistry of the crystalline state are also highlighted.Recent discoveries in the glass formation of metal–organic frameworks via the conventional melt-quenching route are highlighted. In addition to the distinction and prevalence of this novel type of melt-quenched hybrid glass, potential technical advantages and applications together with its perspectives are described.
      PubDate: 2017-01-13T07:45:34.219965-05:
      DOI: 10.1002/adma.201601705
       
  • Molecular Engineering of Conjugated Polymers for Solar Cells: An Updated
           Report
    • Authors: Shengqiang Xiao; Qianqian Zhang, Wei You
      Abstract: The device efficiency of polymer:fullerene bulk heterojunction solar cells has recently surpassed 11%, as a result of synergistic efforts among chemists, physicists, and engineers. Since polymers are unequivocally the “heart” of this emerging technology, their design and synthesis have consistently played the key role in the device efficiency enhancement. In this article, the first focus is a discussion on molecular engineering (e.g., backbone, side chains, and substituents), then the discussion moves on to polymer engineering (e.g., molecular weight). Examples are primarily selected from the authors contributions; yet other significant discoveries/developments are also included to put the discussion in a broader context. Given that the synthesis, morphology, and device physics are inherently related in explaining the measured device output parameters (Jsc, Voc and FF), we will attempt to apply an integrated and comprehensive approach (synthesis, morphology, and device physics) to elucidate the fundamental, underlying principles that govern the device characteristics, in particular, in the context of disclosing structure-property correlations. Such correlations are crucial to the design and synthesis of next generation materials to further improve the device efficiency.Recent progress (2012–2016) in polymer:fullerene bulk-heterojunction solar cells is reviewed. The intrinsic complexity of such solar cells urges the community to apply an integrated and comprehensive approach – including synthesis, morphology, and device physics – to elucidate the fundamental underlying principles that govern the device performance, in particular, in the context of disclosing structure–property correlations.
      PubDate: 2016-12-30T11:00:46.13315-05:0
      DOI: 10.1002/adma.201601391
       
  • Engineered Graphene Materials: Synthesis and Applications for Polymer
           Electrolyte Membrane Fuel Cells
    • Authors: Daping He; Haolin Tang, Zongkui Kou, Mu Pan, Xueliang Sun, Jiujun Zhang, Shichun Mu
      Abstract: Engineered graphene materials (EGMs) with unique structures and properties have been incorporated into various components of polymer electrolyte membrane fuel cells (PEMFCs) such as electrode, membrane, and bipolar plates to achieve enhanced performances in terms of electrical conductivity, mechanical durability, corrosion resistance, and electrochemical surface area. This research news article provides an overview of the recent development in EGMs and EGM-based PEMFCs with a focus on the effects of EGMs on PEMFC performance when they are incorporated into different components of PEMFCs. The challenges of EGMs for practical PEMFC applications in terms of production scale, stability, conductivity, and coupling capability with other materials are also discussed and the corresponding measures and future research trends to overcome such challenges are proposed.The latest discoveries and achievements in engineered graphene materials (EGMs) toward polymer electrolyte membrane fuel cells (PEMFCs) are presented and highlighted, focusing on the effects of EGMs on PEMFC performance and lifetime when they are incorporated into different components, including catalyst layers, polymer electrolyte membranes, and bipolars of PEMFCs.
      PubDate: 2016-12-20T07:55:26.770047-05:
      DOI: 10.1002/adma.201601741
       
  • Singlet Fission: Progress and Prospects in Solar Cells
    • Authors: Jianlong Xia; Samuel N. Sanders, Wei Cheng, Jonathan Z. Low, Jinping Liu, Luis M. Campos, Taolei Sun
      Abstract: The third generation of photovoltaic technology aims to reduce the fabrication cost and improve the power conversion efficiency (PCE) of solar cells. Singlet fission (SF), an efficient multiple exciton generation (MEG) process in organic semiconductors, is one promising way to surpass the Shockley-Queisser limit of conventional single-junction solar cells. Traditionally, this MEG process has been observed as an intermolecular process in organic materials. The implementation of intermolecular SF in photovoltaic devices has achieved an external quantum efficiency of over 100% and demonstrated significant promise for boosting the PCE of third generation solar cells. More recently, efficient intramolecular SF has been reported. Intramolecular SF materials are modular and have the potential to overcome certain design constraints that intermolecular SF materials possess, which may allow for more facile integration into devices.Singlet fission (SF), a multiple exciton generation process in organic semiconductors, is one promising way to overcome the Shockley–Queisser limit for the power conversion efficiency (PCE) of photovoltaic solar cells. Recent achievements in engineering intermolecular SF-based photovoltaic devices and prospects of recently developed intramolecular SF materials as active layers in future devices are highlighted.
      PubDate: 2016-12-14T11:25:31.216541-05:
      DOI: 10.1002/adma.201601652
       
 
 
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