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Publisher: John Wiley and Sons   (Total: 1579 journals)

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Showing 1 - 200 of 1579 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 13, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 65, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 47, SJR: 0.547, h-index: 30)
ACEP NOW     Free   (Followers: 1)
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 52, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 156, 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: 6, SJR: 0.112, h-index: 1)
Acta Paediatrica     Hybrid Journal   (Followers: 56, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 6, SJR: 1.69, h-index: 88)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Acta Psychiatrica Scandinavica     Hybrid Journal   (Followers: 35, SJR: 2.518, h-index: 113)
Acta Zoologica     Hybrid Journal   (Followers: 6, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 4)
Addiction     Hybrid Journal   (Followers: 35, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 13, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 27, SJR: 6.411, h-index: 86)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 51, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 14, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 265, 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: 6, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 5)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17, SJR: 2.729, h-index: 121)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13, SJR: 0.344, h-index: 31)
Africa Confidential     Hybrid Journal   (Followers: 21)
Africa Research Bulletin: Economic, Financial and Technical Series     Hybrid Journal   (Followers: 13)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 10)
African Development Review     Hybrid Journal   (Followers: 33, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 15, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 15, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 11, 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: 16, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 45, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 31, 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: 51, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 143, 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: 90, 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: 33, 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: 16, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 4, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 6, SJR: 2.315, h-index: 79)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 37, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 269, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 15, SJR: 1.197, h-index: 63)
American J. of Reproductive Immunology     Hybrid Journal   (Followers: 3, SJR: 1.347, h-index: 75)
American J. of Transplantation     Hybrid Journal   (Followers: 17, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 9, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 134, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 10, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 18)
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: 193)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 218, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 39, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 6, SJR: 0.569, h-index: 24)
Annalen der Physik     Hybrid Journal   (Followers: 5, SJR: 1.46, h-index: 40)
Annals of Anthropological Practice     Partially Free   (Followers: 2, SJR: 0.187, h-index: 5)
Annals of Applied Biology     Hybrid Journal   (Followers: 7, 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: 47, 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: 13)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 25, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 17, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 15)
Anthropology of Consciousness     Hybrid Journal   (Followers: 11, SJR: 0.172, h-index: 5)
Anthropology of Work Review     Hybrid Journal   (Followers: 11, SJR: 0.256, h-index: 5)
Anthropology Today     Hybrid Journal   (Followers: 91, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 48, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 7, 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: 70, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 198, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 49, SJR: 0.868, h-index: 13)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5, SJR: 0.613, h-index: 24)
Aquaculture Nutrition     Hybrid Journal   (Followers: 14, SJR: 1.025, h-index: 55)
Aquaculture Research     Hybrid Journal   (Followers: 31, SJR: 0.807, h-index: 60)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 36, 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: 15, SJR: 0.156, h-index: 2)
Architectural Design     Hybrid Journal   (Followers: 25, SJR: 0.261, h-index: 9)
Archiv der Pharmazie     Hybrid Journal   (Followers: 4, SJR: 0.628, h-index: 43)
Archives of Drug Information     Hybrid Journal   (Followers: 5)
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: 243, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 50, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 26, SJR: 2.256, h-index: 114)
Artificial Organs     Hybrid Journal   (Followers: 1, SJR: 0.872, h-index: 60)
ASHE Higher Education Reports     Hybrid Journal   (Followers: 14)
Asia & the Pacific Policy Studies     Open Access   (Followers: 16)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 321, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (Followers: 1, SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 8, 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: 4, SJR: 0.377, h-index: 7)
Asian Economic J.     Hybrid Journal   (Followers: 8, SJR: 0.234, h-index: 21)
Asian Economic Policy Review     Hybrid Journal   (Followers: 4, SJR: 0.196, h-index: 12)
Asian J. of Control     Hybrid Journal   (SJR: 0.862, h-index: 34)
Asian J. of Endoscopic Surgery     Hybrid Journal   (SJR: 0.394, h-index: 7)
Asian J. of Organic Chemistry     Hybrid Journal   (Followers: 5, SJR: 1.443, h-index: 19)
Asian J. of Social Psychology     Hybrid Journal   (Followers: 5, SJR: 0.665, h-index: 37)
Asian Politics and Policy     Hybrid Journal   (Followers: 12, SJR: 0.207, h-index: 7)
Asian Social Work and Policy Review     Hybrid Journal   (Followers: 5, SJR: 0.318, h-index: 5)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5, SJR: 0.168, h-index: 15)
Assessment Update     Hybrid Journal   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 2, SJR: 0.701, h-index: 40)
Atmospheric Science Letters     Open Access   (Followers: 29, SJR: 1.332, h-index: 27)
Austral Ecology     Hybrid Journal   (Followers: 15, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 9, SJR: 0.524, h-index: 28)
Australasian J. of Dermatology     Hybrid Journal   (Followers: 8, SJR: 0.714, h-index: 40)
Australasian J. On Ageing     Hybrid Journal   (Followers: 6, SJR: 0.39, h-index: 22)
Australian & New Zealand J. of Statistics     Hybrid Journal   (Followers: 14, SJR: 0.275, h-index: 28)
Australian Accounting Review     Hybrid Journal   (Followers: 4, SJR: 0.709, h-index: 14)
Australian and New Zealand J. of Family Therapy (ANZJFT)     Hybrid Journal   (Followers: 3, SJR: 0.382, h-index: 12)
Australian and New Zealand J. of Obstetrics and Gynaecology     Hybrid Journal   (Followers: 47, SJR: 0.814, h-index: 49)
Australian and New Zealand J. of Public Health     Hybrid Journal   (Followers: 11, SJR: 0.82, h-index: 62)
Australian Dental J.     Hybrid Journal   (Followers: 7, SJR: 0.482, h-index: 46)
Australian Economic History Review     Hybrid Journal   (Followers: 4, SJR: 0.171, h-index: 12)
Australian Economic Papers     Hybrid Journal   (Followers: 29, 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: 14, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 18, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 406, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 5, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 72, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 12, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 20, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 34, 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: 11, SJR: 0.539, h-index: 70)
Basic and Applied Pathology     Open Access   (Followers: 2, SJR: 0.113, h-index: 4)
Basin Research     Hybrid Journal   (Followers: 5, SJR: 1.54, h-index: 60)
Bauphysik     Hybrid Journal   (Followers: 2, SJR: 0.194, h-index: 5)
Bauregelliste A, Bauregelliste B Und Liste C     Hybrid Journal  
Bautechnik     Hybrid Journal   (Followers: 1, SJR: 0.321, h-index: 11)
Behavioral Interventions     Hybrid Journal   (Followers: 9, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 24, 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: 16, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 4, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 42, SJR: 0.12, h-index: 1)
Biology of the Cell     Full-text available via subscription   (Followers: 9, SJR: 1.812, h-index: 69)
Biomedical Chromatography     Hybrid Journal   (Followers: 6, SJR: 0.572, h-index: 49)
Biometrical J.     Hybrid Journal   (Followers: 5, SJR: 0.784, h-index: 44)
Biometrics     Hybrid Journal   (Followers: 36, 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: 160, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 14, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 20, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 9, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 38, 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: 6, SJR: 0.468, h-index: 47)
Birth Defects Research Part C : Embryo Today : Reviews     Hybrid Journal   (SJR: 1.513, h-index: 55)
BJOG : An Intl. J. of Obstetrics and Gynaecology     Partially Free   (Followers: 241, SJR: 2.083, h-index: 125)

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Journal Cover Advanced Materials
  [SJR: 9.021]   [H-I: 345]   [265 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  [1579 journals]
  • Multiscale Geometric Design Principles Applied to 3D Printed Schwarzites
    • Authors: Seyed Mohammad Sajadi; Peter Samora Owuor, Steven Schara, Cristiano F. Woellner, Varlei Rodrigues, Robert Vajtai, Jun Lou, Douglas S. Galvão, Chandra Sekhar Tiwary, Pulickel M. Ajayan
      Abstract: Schwartzites are 3D porous solids with periodic minimal surfaces having negative Gaussian curvatures and can possess unusual mechanical and electronic properties. The mechanical behavior of primitive and gyroid schwartzite structures across different length scales is investigated after these geometries are 3D printed at centimeter length scales based on molecular models. Molecular dynamics and finite elements simulations are used to gain further understanding on responses of these complex solids under compressive loads and kinetic impact experiments. The results show that these structures hold great promise as high load bearing and impact-resistant materials due to a unique layered deformation mechanism that emerges in these architectures during loading. Easily scalable techniques such as 3D printing can be used for exploring mechanical behavior of various predicted complex geometrical shapes to build innovative engineered materials with tunable properties.Schwartzites are 3D porous solids with periodic minimal surfaces having negative Gaussian curvatures and can possess unusual mechanical and electronic properties. This work investigates their mechanical behavior on the primitive and gyroid families across different length scales after these geometries are 3D printed at centimeter length scales based on molecular models.
      PubDate: 2017-11-15T13:42:20.805126-05:
      DOI: 10.1002/adma.201704820
       
  • Contents: (Adv. Mater. 43/2017)
    • PubDate: 2017-11-14T06:18:07.239614-05:
      DOI: 10.1002/adma.201770311
       
  • 2D Materials: Re Doping in 2D Transition Metal Dichalcogenides as a New
           Route to Tailor Structural Phases and Induced Magnetism (Adv. Mater.
           43/2017)
    • Authors: Vidya Kochat; Amey Apte, Jordan A. Hachtel, Hiroyuki Kumazoe, Aravind Krishnamoorthy, Sandhya Susarla, Juan Carlos Idrobo, Fuyuki Shimojo, Priya Vashishta, Rajiv Kalia, Aiichiro Nakano, Chandra Sekhar Tiwary, Pulickel M. Ajayan
      Abstract: In article number 1703754, Aravind Krishnamoorthy, Chandra Sekhar Tiwary, Pulickel M. Ajayan, and co-workers show that Re-doping of transition-metal-dichalcogenide monolayers during chemical vapor deposition (CVD) offers a simple way to controllably tune crystal structure and phase composition in two-dimensional alloys. The CVD-synthesized MoReSe2 alloys show composition-dependent electronic structures and magnetic properties.
      PubDate: 2017-11-14T06:18:04.142988-05:
      DOI: 10.1002/adma.201770315
       
  • Mechanoluminescence: Temporal and Remote Tuning of
           Piezophotonic-Effect-Induced Luminescence and Color Gamut via Modulating
           Magnetic Field (Adv. Mater. 43/2017)
    • Authors: Man-Chung Wong; Li Chen, Gongxun Bai, Long-Biao Huang, Jianhua Hao
      Abstract: A novel physical method is developed to tune light-emitting wavelengths and color. Piezophotonic luminescence from the flexible composites of ZnS: Al, Cu phosphors is tuned by modulating the frequency of the magnetic-field excitation at room temperature, as reported by Jianhua Hao and co-workers in article number 1701945. A new understanding of piezophotonic luminescence and magnetic-optics coupling is thus provided.
      PubDate: 2017-11-14T06:18:03.804499-05:
      DOI: 10.1002/adma.201770313
       
  • Liquid Crystals: A Fluid Liquid-Crystal Material with Highly Polar Order
           (Adv. Mater. 43/2017)
    • Authors: Hiroya Nishikawa; Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago, Hirotsugu Kikuchi
      Abstract: A calamitic-liquid-crystal compound with 1,3-dioxane and fluorinated aryl units exhibits a highly polar and fluid mesophase (MP phase) in which anomalously large dielectric permittivity (>10 000), ferroelectric-like polarization switching, and second-harmonic generation are observed by Hiroya Nishikawa, Hirotsugu Kikuchi, and co-workers in article number 1702354. The experimental data clearly shows that a unidirectional ferroelectric-like polar order is generated along the director, although there is no layer structure.
      PubDate: 2017-11-14T06:18:03.744377-05:
      DOI: 10.1002/adma.201770309
       
  • Wearable Electronics: A Superhydrophobic Smart Coating for Flexible and
           Wearable Sensing Electronics (Adv. Mater. 43/2017)
    • Authors: Lianhui Li; Yuanyuan Bai, Lili Li, Shuqi Wang, Ting Zhang
      Abstract: A superhydrophobic smart sensing coating is presented by Ting Zhang and co-workers in article 1702517, which can be integrated on running clothes. The coatings are piezoresistive for wearable strain-sensor applications and superhydrophobic for water repellency, and are thus endowed with highly sensitive and stable sensing performance under wet/corrosive conditions.
      PubDate: 2017-11-14T06:17:59.771249-05:
      DOI: 10.1002/adma.201770310
       
  • Masthead: (Adv. Mater. 43/2017)
    • PubDate: 2017-11-14T06:17:59.374866-05:
      DOI: 10.1002/adma.201770312
       
  • Perovskite Photoluminescence: Direct Observation of Halide Migration and
           its Effect on the Photoluminescence of Methylammonium Lead Bromide
           Perovskite Single Crystals (Adv. Mater. 43/2017)
    • Authors: Yanqi Luo; Parisa Khoram, Sarah Brittman, Zhuoying Zhu, Barry Lai, Shyue Ping Ong, Erik C. Garnett, David P. Fenning
      Abstract: In article number 1703451, direct evidence of bromine migration in CH3NH3PbBr3 single crystals under electric-field cycles is reported by David P. Fenning and co-workers, using nanoprobe X-ray fluorescence. Photoluminescence mapping reveals that the crystal has higher emission in regions with higher local bromine concentration. This link between ion migration and optoelectronic quality reveals the importance of controlling the nanoscale material chemistry to optimize performance in hybrid perovskite optoelectronic materials.
      PubDate: 2017-11-14T06:17:58.274357-05:
      DOI: 10.1002/adma.201770314
       
  • Editable Supercapacitors with Customizable Stretchability Based on
           Mechanically Strengthened Ultralong MnO2 Nanowire Composite
    • Authors: Zhisheng Lv; Yifei Luo, Yuxin Tang, Jiaqi Wei, Zhiqiang Zhu, Xinran Zhou, Wenlong Li, Yi Zeng, Wei Zhang, Yanyan Zhang, Dianpeng Qi, Shaowu Pan, Xian Jun Loh, Xiaodong Chen
      Abstract: Although some progress has been made on stretchable supercapacitors, traditional stretchable supercapacitors fabricated by predesigning structured electrodes for device assembling still lack the device-level editability and programmability. To adapt to wearable electronics with arbitrary configurations, it is highly desirable to develop editable supercapacitors that can be directly transferred into desirable shapes and stretchability. In this work, editable supercapacitors for customizable shapes and stretchability using electrodes based on mechanically strengthened ultralong MnO2 nanowire composites are developed. A supercapacitor edited with honeycomb-like structure shows a specific capacitance of 227.2 mF cm−2 and can be stretched up to 500% without degradation of electrochemical performance, which is superior to most of the state-of-the-art stretchable supercapacitors. In addition, it maintains nearly 98% of the initial capacitance after 10 000 stretch-and-release cycles under 400% tensile strain. As a representative of concept for system integration, the editable supercapacitors are integrated with a strain sensor, and the system exhibits a stable sensing performance even under arm swing. Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, stretchable, and wearable devices.Editable supercapacitors with customizable stretchability, which can be directly transformed into various customizable shapes and stretchable structures, are developed. In particular, the supercapacitor with a honeycomb-like structure can maintain nearly 98% initial capacitance even after 10 000 stretch-and-release cycles under reversible 400% tensile strain.
      PubDate: 2017-11-14T02:32:30.922486-05:
      DOI: 10.1002/adma.201704531
       
  • Ideal Bandgap Organic–Inorganic Hybrid Perovskite Solar Cells
    • Authors: Zhibin Yang; Adharsh Rajagopal, Alex K.-Y. Jen
      Abstract: Extremely high power conversion efficiencies (PCEs) of ≈20–22% are realized through intensive research and development of 1.5–1.6 eV bandgap perovskite absorbers. However, development of ideal bandgap (1.3–1.4 eV) absorbers is pivotal to further improve PCE of single junction perovskite solar cells (PVSCs) because of a better balance between absorption loss of sub-bandgap photons and thermalization loss of above-bandgap photons as demonstrated by the Shockley–Queisser detailed balanced calculation. Ideal bandgap PVSCs are currently hindered by the poor optoelectronic quality of perovskite absorbers and their PCEs have stagnated at
      PubDate: 2017-11-14T02:31:50.203356-05:
      DOI: 10.1002/adma.201704418
       
  • Direct Probing of Polarization Charge at Nanoscale Level
    • Authors: Owoong Kwon; Daehee Seol, Dongkyu Lee, Hee Han, Ionela Lindfors-Vrejoiu, Woo Lee, Stephen Jesse, Ho Nyung Lee, Sergei V. Kalinin, Marin Alexe, Yunseok Kim
      Abstract: Ferroelectric materials possess spontaneous polarization that can be used for multiple applications. Owing to a long-term development of reducing the sizes of devices, the preparation of ferroelectric materials and devices is entering the nanometer-scale regime. Accordingly, to evaluate the ferroelectricity, there is a need to investigate the polarization charge at the nanoscale. Nonetheless, it is generally accepted that the detection of polarization charges using a conventional conductive atomic force microscopy (CAFM) without a top electrode is not feasible because the nanometer-scale radius of an atomic force microscopy (AFM) tip yields a very low signal-to-noise ratio. However, the detection is unrelated to the radius of an AFM tip and, in fact, a matter of the switched area. In this work, the direct probing of the polarization charge at the nanoscale is demonstrated using the positive-up-negative-down method based on the conventional CAFM approach without additional corrections or circuits to reduce the parasitic capacitance. The polarization charge densities of 73.7 and 119.0 µC cm−2 are successfully probed in ferroelectric nanocapacitors and thin films, respectively. The obtained results show the feasibility of the evaluation of polarization charge at the nanoscale and provide a new guideline for evaluating the ferroelectricity at the nanoscale.The evaluation of polarization charge at the nanoscale is of great interest, but it is hard to acquire polarization charge due to the low signal-to-noise ratio. However, the polarization charge can be obtained by applying the positive-up-negative-down method to the conventional conductive atomic force microscopy system without any other circuits. Through this method, polarization charge can be evaluated at the nanoscale.
      PubDate: 2017-11-14T02:31:35.400993-05:
      DOI: 10.1002/adma.201703675
       
  • Synthesis and Properties of a Photopatternable Lithium-Ion Conducting
           Solid Electrolyte
    • Authors: Christopher S. Choi; Jonathan Lau, Janet Hur, Leland Smith, Chunlei Wang, Bruce Dunn
      Abstract: One of the important considerations for the development of on-chip batteries is the need to photopattern the solid electrolyte directly on electrodes. Herein, the photopatterning of a lithium-ion conducting solid electrolyte is demonstrated by modifying a well-known negative photoresist, SU-8, with LiClO4. The resulting material exhibits a room temperature ionic conductivity of 52 µS cm−1 with a wide electrochemical window (>5 V). Half-cell galvanostatic testing of 3 µm thin films spin-coated on amorphous silicon validates its use for on-chip energy-storage applications. The modified SU-8 possesses excellent mechanical integrity, is thermally stable up to 250 °C, and can be photopatterned with micrometer-scale resolution. These results present a promising direction for the integration of electrochemical energy storage in microelectronics.The photopatterning of a lithium-ion conducting solid electrolyte is demonstrated by modifying a negative photoresist, SU-8, with lithium salts. The patterned material exhibits good electrochemical properties with a room temperature ionic conductivity of 52 µS cm−1, which is comparable to polymer solid electrolytes. The materials also demonstrate excellent mechanical integrity and thermal stability.
      PubDate: 2017-11-14T02:30:34.528142-05:
      DOI: 10.1002/adma.201703772
       
  • Water-Rich Biomimetic Composites with Abiotic Self-Organizing Nanofiber
           Network
    • Authors: Lizhi Xu; Xueli Zhao, Chuanlai Xu, Nicholas A. Kotov
      Abstract: Load-bearing soft tissues, e.g., cartilage, ligaments, and blood vessels, are made predominantly from water (65–90%) which is essential for nutrient transport to cells. Yet, they display amazing stiffness, toughness, strength, and deformability attributed to the reconfigurable 3D network from stiff collagen nanofibers and flexible proteoglycans. Existing hydrogels and composites partially achieve some of the mechanical properties of natural soft tissues, but at the expense of water content. Concurrently, water-rich biomedical polymers are elastic but weak. Here, biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol), with water contents of as high as 70–92%, are reported. With tensile moduli of ≈9.1 MPa, ultimate tensile strains of ≈325%, compressive strengths of ≈26 MPa, and fracture toughness of as high as ≈9200 J m−2, their mechanical properties match or exceed those of prototype tissues, e.g., cartilage. Furthermore, with reconfigurable, noncovalent interactions at nanomaterial interfaces, the composite nanofiber network can adapt itself under stress, enabling abiotic soft tissue with multiscale self-organization for effective load bearing and energy dissipation.Water-rich biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol) emulate the collagen–proteoglycan network in load-bearing soft tissues. The hydrogen bonding between stiff nanofibers and soft polymers affords synergistic stiffening and toughening, allowing the nanofiber network to self-organize under stress for effective load bearing and energy dissipation. Their mechanics, biocompatibility, and high water content permit utilization as load-bearing biomaterials and for other applications including durable high transport rate membranes membranes in water desalination, fuel cells, and batteries.
      PubDate: 2017-11-14T01:02:00.455644-05:
      DOI: 10.1002/adma.201703343
       
  • The Role of Interfaces in Polyethylene/Metal-Oxide Nanocomposites for
           Ultrahigh-Voltage Insulating Materials
    • Authors: Amir Masoud Pourrahimi; Richard T. Olsson, Mikael S. Hedenqvist
      Abstract: Recent progress in the development of polyethylene/metal-oxide nanocomposites for extruded high-voltage direct-current (HVDC) cables with ultrahigh electric insulation properties is presented. This is a promising technology with the potential of raising the upper voltage limit in today's underground/submarine cables, based on pristine polyethylene, to levels where the loss of energy during electric power transmission becomes low enough to ensure intercontinental electric power transmission. The development of HVDC insulating materials together with the impact of the interface between the particles and the polymer on the nanocomposites electric properties are shown. Important parameters from the atomic to the microlevel, such as interfacial chemistry, interfacial area, and degree of particle dispersion/aggregation, are discussed. This work is placed in perspective with important work by others, and suggested mechanisms for improved insulation using nanoparticles, such as increased charge trap density, adsorption of impurities/ions, and induced particle dipole moments are considered. The effects of the nanoparticles and of their interfacial structures on the mechanical properties and the implications of cavitation on the electric properties are also discussed. Although the main interest in improving the properties of insulating polymers has been on the use of nanoparticles, leading to nanodielectrics, it is pointed out here that larger microscopic hierarchical metal-oxide particles with high surface porosity also impart good insulation properties. The impact of the type of particle and its inherent properties (purity and conductivity) on the nanocomposite dielectric and insulating properties are also discussed based on data obtained by a newly developed technique to directly observe the charge distribution on a nanometer scale in the nanocomposite.Recent progress in the development of polyethylene/metal-oxide nanocomposites with “optimal” interfaces for the next generation of extruded high-voltage direct-current cables with ultralow transmission-loss is presented. This is the most promising way of delivering clean and renewable energy from remote areas to more densely populated regions.
      PubDate: 2017-11-13T10:52:21.313091-05:
      DOI: 10.1002/adma.201703624
       
  • Superior Toughness and Fast Self-Healing at Room Temperature Engineered by
           Transparent Elastomers
    • Authors: Seon-Mi Kim; Hyeonyeol Jeon, Sung-Ho Shin, Seul-A Park, Jonggeon Jegal, Sung Yeon Hwang, Dongyeop X. Oh, Jeyoung Park
      Abstract: The most important properties of self-healing polymers are efficient recovery at room temperature and prolonged durability. However, these two characteristics are contradictory, making it difficult to optimize them simultaneously. Herein, a transparent and easily processable thermoplastic polyurethane (TPU) with the highest reported tensile strength and toughness (6.8 MPa and 26.9 MJ m−3, respectively) is prepared. This TPU is superior to reported contemporary room-temperature self-healable materials and conveniently heals within 2 h through facile aromatic disulfide metathesis engineered by hard segment embedded aromatic disulfides. After the TPU film is cut in half and respliced, the mechanical properties recover to more than 75% of those of the virgin sample within 2 h. Hard segments with an asymmetric alicyclic structure are more effective than those with symmetric alicyclic, linear aliphatic, and aromatic structures. An asymmetric structure provides the optimal metathesis efficiency for the embedded aromatic disulfide while preserving the remarkable mechanical properties of TPU, as indicated by rheological and surface investigations. The demonstration of a scratch-detecting electrical sensor coated on a tough TPU film capable of auto-repair at room temperature suggests that this film has potential applications in the wearable electronics industry.Remarkably tough and room-temperature self-healable thermoplastic polyurethane (TPU) elastomers are engineered by hard segment embedding aromatic disulfides. Hard segments with asymmetric alicyclic structure have adequate packing density to achieve efficient self-healing and to retain the remarkable mechanical properties of TPU. Their toughness value of 26.9 MJ m−3 doubles previous records. A scratch-detecting and auto-repairing electrical sensor application is demonstrated.
      PubDate: 2017-11-13T06:22:59.772432-05:
      DOI: 10.1002/adma.201705145
       
  • The Salt Matters: Enhanced Reversibility of Li–O2 Batteries with a
           Li[(CF3SO2)(n-C4F9SO2)N]-Based Electrolyte
    • Authors: Bo Tong; Jun Huang, Zhibin Zhou, Zhangquan Peng
      Abstract: The safety hazards and cycle instability of lithium metal anodes (LMA) constitute significant barriers to progress in lithium metal batteries. This situation is worse in Li–O2 batteries because the LMA is prone to be chemically attacked by O2 shuttled from the cathode. Notwithstanding, efforts on LMA are much sparse than those on the cathode in the realm of Li–O2 batteries. Here, a novel lithium salt of Li[(CF3SO2)(n-C4F9SO2)N] (LiTNFSI) is reported, which can effectively suppress the parasitic side reactions and dendrite growth of LMA during cycling and thereby significantly enhance the overall reversibility of Li–O2 batteries. A variety of advanced research tools are employed to scrutinize the working principles of the LiTNFSI salt. It is revealed that a stable, uniform, and O2-resistive solid electrolyte interphase is formed on LMA, and hence the “cross-talk” between the LMA and O2 shuttled from the cathode is remarkably inhibited in LiTNFSI-based Li–O2 batteries.A lithium salt comprising Li[(CF3SO2)(n-C4F9SO2)N] (LiTNFSI) is introduced to stabilize the lithium metal anode (LMA) in aprotic Li–O2 batteries. When combined with tetraglyme, the benchmark solvent of current Li–O2 batteries, the LiTNFSI enables the formation of a stable, uniform, and O2-resistive solid electrolyte interphase on LMA, and drastically enhances the reversibility of Li–O2 batteries.
      PubDate: 2017-11-13T06:22:00.884906-05:
      DOI: 10.1002/adma.201704841
       
  • Highly Efficient Porphyrin-Based OPV/Perovskite Hybrid Solar Cells with
           Extended Photoresponse and High Fill Factor
    • Authors: Ke Gao; Zonglong Zhu, Bo Xu, Sae Byeok Jo, Yuanyuan Kan, Xiaobin Peng, Alex K.-Y. Jen
      Abstract: Employing a layer of bulk-heterojunction (BHJ) organic semiconductors on top of perovskite to further extend its photoresponse is considered as a simple and promising way to enhance the efficiency of perovskite-based solar cells, instead of using tandem devices or near infrared (NIR)-absorbing Sn-containing perovskites. However, the progress made from this approach is quite limited because very few such hybrid solar cells can simultaneously show high short-circuit current (JSC) and fill factor (FF). To find an appropriate NIR-absorbing BHJ is essential for highly efficient, organic, photovoltaics (OPV)/perovskite hybrid solar cells. The materials involved in the BHJ layer not only need to have broad photoresponse to increase JSC, but also possess suitable energy levels and high mobility to afford high VOC and FF. In this work, a new porphyrin is synthesized and blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) to function as an efficient BHJ for OPV/perovskite hybrid solar cells. The extended photoresponse, well-matched energy levels, and high hole mobility from optimized BHJ morphology afford a very high power conversion efficiency (PCE) (19.02%) with high Voc, JSC, and FF achieved simultaneously. This is the highest value reported so far for such hybrid devices, which demonstrates the feasibility of further improving the efficiency of perovskite devices.A highly efficient organic photovoltaics/perovskite hybrid solar cell is demonstrated by blending a new conjugated porphyrin-based small molecule with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) to function as an efficient bulk-heterojunction layer. The extended photoresponse, matched energy levels, and high hole mobility derived from the optimized bulk-heterojunction morphology contribute to the record-high efficiency of 19.02% in these hybrid devices.
      PubDate: 2017-11-13T06:21:38.134117-05:
      DOI: 10.1002/adma.201703980
       
  • Water-Lubricated Intercalation in V2O5·nH2O for High-Capacity and
           High-Rate Aqueous Rechargeable Zinc Batteries
    • Authors: Mengyu Yan; Pan He, Ying Chen, Shanyu Wang, Qiulong Wei, Kangning Zhao, Xu Xu, Qinyou An, Yi Shuang, Yuyan Shao, Karl T. Mueller, Liqiang Mai, Jun Liu, Jihui Yang
      Abstract: Low-cost, environment-friendly aqueous Zn batteries have great potential for large-scale energy storage, but the intercalation of zinc ions in the cathode materials is challenging and complex. Herein, the critical role of structural H2O on Zn2+ intercalation into bilayer V2O5·nH2O is demonstrated. The results suggest that the H2O-solvated Zn2+ possesses largely reduced effective charge and thus reduced electrostatic interactions with the V2O5 framework, effectively promoting its diffusion. Benefited from the “lubricating” effect, the aqueous Zn battery shows a specific energy of ≈144 Wh kg−1 at 0.3 A g−1. Meanwhile, it can maintain an energy density of 90 Wh kg−1 at a high power density of 6.4 kW kg−1 (based on the cathode and 200% Zn anode), making it a promising candidate for high-performance, low-cost, safe, and environment-friendly energy-storage devices.The co-intercalation of H2O and Zn2+ as well as the “lubricating effect” of water in V2O5·nH2O is demonstrated, which enhances the rate capability and energy density of zinc batteries. A combination of an ultrahigh power density of 6.4 kW kg−1 and a high energy density of 144 Wh kg−1 is achieved in aqueous rechargeable zinc batteries.
      PubDate: 2017-11-13T06:21:11.274581-05:
      DOI: 10.1002/adma.201703725
       
  • Voltage-Controlled On/Off Switching of Ferromagnetism in Manganite
           Supercapacitors
    • Authors: Alan Molinari; Horst Hahn, Robert Kruk
      Abstract: The ever-growing technological demand for more advanced microelectronic and spintronic devices keeps catalyzing the idea of controlling magnetism with an electric field. Although voltage-driven on/off switching of magnetization is already established in some magnetoelectric (ME) systems, often the coupling between magnetic and electric order parameters lacks an adequate reversibility, energy efficiency, working temperature, or switching speed. Here, the ME performance of a manganite supercapacitor composed of a ferromagnetic, spin-polarized ultrathin film of La0.74Sr0.26MnO3 (LSMO) electrically charged with an ionic liquid electrolyte is investigated. Fully reversible, rapid, on/off switching of ferromagnetism in LSMO is demonstrated in combination with a shift in Curie temperature of up to 26 K and a giant ME coupling coefficient of ≈226 Oe V−1. The application of voltages of only ≈2 V results in ultralow energy consumptions of about 90 µJ cm−2. This work provides a step forward toward low-power, high-endurance electrical switching of magnetism for the development of high-performance ME spintronics.Ferromagnetism of ultrathin films of LaSrMnO3 is reversibly switched on/off using an ionic liquid electrolyte as charging/discharging medium. It is demonstrated that solid/liquid magnetic supercapacitors allow for giant magnetoelectric effects in combination with high performance in terms of device endurance, switching speed, and energy consumption.
      PubDate: 2017-11-13T06:20:45.211038-05:
      DOI: 10.1002/adma.201703908
       
  • An Ideal Molecular Sieve for Acetylene Removal from Ethylene with Record
           Selectivity and Productivity
    • Authors: Bin Li; Xili Cui, Daniel O'Nolan, Hui-Min Wen, Mengdie Jiang, Rajamani Krishna, Hui Wu, Rui-Biao Lin, Yu-Sheng Chen, Daqiang Yuan, Huabin Xing, Wei Zhou, Qilong Ren, Guodong Qian, Michael J. Zaworotko, Banglin Chen
      Abstract: Realization of ideal molecular sieves, in which the larger gas molecules are completely blocked without sacrificing high adsorption capacities of the preferred smaller gas molecules, can significantly reduce energy costs for gas separation and purification and thus facilitate a possible technological transformation from the traditional energy-intensive cryogenic distillation to the energy-efficient, adsorbent-based separation and purification in the future. Although extensive research endeavors are pursued to target ideal molecular sieves among diverse porous materials, over the past several decades, ideal molecular sieves for the separation and purification of light hydrocarbons are rarely realized. Herein, an ideal porous material, SIFSIX-14-Cu-i (also termed as UTSA-200), is reported with ultrafine tuning of pore size (3.4 Å) to effectively block ethylene (C2H4) molecules but to take up a record-high amount of acetylene (C2H2, 58 cm3 cm−3 under 0.01 bar and 298 K). The material therefore sets up new benchmarks for both the adsorption capacity and selectivity, and thus provides a record purification capacity for the removal of trace C2H2 from C2H4 with 1.18 mmol g−1 C2H2 uptake capacity from a 1/99 C2H2/C2H4 mixture to produce 99.9999% pure C2H4 (much higher than the acceptable purity of 99.996% for polymer-grade C2H4), as demonstrated by experimental breakthrough curves.An ideal molecular sieve is realized for the highly efficient removal of C2H2 from C2H2/C2H4 (1:99) mixture, attributed to the optimized pore sizes to efficiently block C2H4 molecules, and strong binding sites to take up a record-high amount of C2H2, thus simultaneously producing high purity C2H4 (99.9999%) with record C2H4 productivity of 87.5 mmol g−1 per cycle and recovery of C2H2 (97%).
      PubDate: 2017-11-10T10:02:50.837313-05:
      DOI: 10.1002/adma.201704210
       
  • Atomic Vacancies Control of Pd-Based Catalysts for Enhanced
           Electrochemical Performance
    • Authors: Yunpeng Zuo; Dewei Rao, Shuo Li, Tingting Li, Guilin Zhu, Shuangming Chen, Li Song, Yang Chai, Heyou Han
      Abstract: Structure-engineered Pd-based catalysts at the atomic level can effectively improve the catalytic performance for oxygen or small organic molecules electrocatalysis, comparable to or even superior to that of commercial Pt/C. Here, PdCuCo anisotropic structure (AS) electrocatalysts are synthesized with abundant vacancy defects on the exterior surface, which is unambiguously verified by aberration-corrected transmission electron microscopy. The PdCuCo-AS with vacancy (v-PdCuCo-AS) shows excellent electrochemical activity toward oxygen reduction (ORR) and oxidation of alcohols. The mass activity of the v-PdCuCo-AS is 0.18 A mg−1 at 0.9 V versus reversible hydrogen electrode (RHE), which is 15.55 times larger than that of the commercial Pd/C catalyst in acidic electrolyte. According to the theoretical calculations, this significant improvement can be understood as a result of the promoted charge transfer by polarized electronic structures of the v-PdCuCo-AS in the processes of ORR. The synergistic effect of the correlated defects and the compressive strain caused by the doping Co and Cu atoms effectively improve the electrocatalysis activity for the ORR in acidic/alkaline electrolyte on the v-PdCuCo-AS stems. This approach provides a strategy to design other AS structures for improving their electrochemical performance.Structure-engineered Pd-based catalysts at the atomic level can effectively improve catalytic performance. Here PdCuCo electrocatalysts are synthesized with abundant vacancy defects on the exterior surface, which is verified by aberration-corrected transmission electron microscopy. The synergistic effect of the correlated defects and compressive strain effectively improves electrocatalysis activity for the oxygen reduction reaction.
      PubDate: 2017-11-10T10:02:16.072353-05:
      DOI: 10.1002/adma.201704171
       
  • Ternary Nonfullerene Polymer Solar Cells with 12.16% Efficiency by
           Introducing One Acceptor with Cascading Energy Level and Complementary
           Absorption
    • Authors: Weigang Jiang; Runnan Yu, Zhiyang Liu, Ruixiang Peng, Dongbo Mi, Ling Hong, Qiang Wei, Jianhui Hou, Yongbo Kuang, Ziyi Ge
      Abstract: A novel small-molecule acceptor, (2,2′-((5E,5′E)-5,5′-((5,5′-(4,4,9,9-tetrakis(5-hexylthiophen-2-yl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(4-(2-ethylhexyl)thiophene-5,2-diyl))bis(methanylylidene)) bis(3-hexyl-4-oxothiazolidine-5,2-diylidene))dimalononitrile (ITCN), end-capped with electron-deficient 2-(3-hexyl-4-oxothiazolidin-2-ylidene)malononitrile groups, is designed, synthesized, and used as the third component in fullerene-free ternary polymer solar cells (PSCs). The cascaded energy-level structure enabled by the newly designed acceptor is beneficial to the carrier transport and separation. Meanwhile, the three materials show a complementary absorption in the visible region, resulting in efficient light harvesting. Hence, the PBDB-T:ITCN:IT-M ternary PSCs possess a high short-circuit current density (Jsc) under an optimal weight ratio of donors and acceptors. Moreover, the open-circuit voltage (Voc) of the ternary PSCs is enhanced with an increase of the third acceptor ITCN content, which is attributed to the higher lowest unoccupied molecular orbital energy level of ITCN than that of IT-M, thus exhibits a higher Voc in PBDB-T:ITCN binary system. Ultimately, the ternary PSCs achieve a power conversion efficiency of 12.16%, which is higher than the PBDB-T:ITM-based PSCs (10.89%) and PBDB-T:ITCN-based ones (2.21%). This work provides an effective strategy to improve the photovoltaic performance of PSCs.Fullerene-free ternary polymer solar cells with a high efficiency of 12.16% are fabricated by adding a novel small-molecule acceptor to form a cascaded energy-level structure.
      PubDate: 2017-11-10T10:01:54.238599-05:
      DOI: 10.1002/adma.201703005
       
  • Enhancing the Quantum Anomalous Hall Effect by Magnetic Codoping in a
           Topological Insulator
    • Authors: Yunbo Ou; Chang Liu, Gaoyuan Jiang, Yang Feng, Dongyang Zhao, Weixiong Wu, Xiao-Xiao Wang, Wei Li, Canli Song, Li-Li Wang, Wenbo Wang, Weida Wu, Yayu Wang, Ke He, Xu-Cun Ma, Qi-Kun Xue
      Abstract: The quantum anomalous Hall (QAH) effect, which has been realized in magnetic topological insulators (TIs), is the key to applications of dissipationless quantum Hall edge states in electronic devices. However, investigations and utilizations of the QAH effect are limited by the ultralow temperatures needed to reach full quantization—usually below 100 mK in either Cr- or V-doped (Bi,Sb)2Te3 of the two experimentally confirmed QAH materials. Here it is shown that by codoping Cr and V magnetic elements in (Bi,Sb)2Te3 TI, the temperature of the QAH effect can be significantly increased such that full quantization is achieved at 300 mK, and zero-field Hall resistance of 0.97 h/e2 is observed at 1.5 K. A systematic transport study of the codoped (Bi,Sb)2Te3 films with varied Cr/V ratios reveals that magnetic codoping improves the homogeneity of ferromagnetism and modulates the surface band structure. This work demonstrates magnetic codoping to be an effective strategy for achieving high-temperature QAH effect in TIs.In Cr and V codoped (Bi,Sb)2Te3 topological insulator films, the quantum anomalous Hall (QAH) effect is achieved at 300 mK, about one order of magnitude higher than that for singly Cr- or V-doped ones, and the energy scale of QAH state reaches 1.4 K. The transport study of the codoped films with varied Cr/V ratios reveals the origins of enhancement.
      PubDate: 2017-11-10T10:01:40.431654-05:
      DOI: 10.1002/adma.201703062
       
  • Bending-Tolerant Anodes for Lithium-Metal Batteries
    • Authors: Aoxuan Wang; Shan Tang, Debin Kong, Shan Liu, Kevin Chiou, Linjie Zhi, Jiaxing Huang, Yong-Yao Xia, Jiayan Luo
      Abstract: Bendable energy-storage systems with high energy density are demanded for conformal electronics. Lithium-metal batteries including lithium–sulfur and lithium–oxygen cells have much higher theoretical energy density than lithium-ion batteries. Reckoned as the ideal anode, however, Li has many challenges when directly used, especially its tendency to form dendrite. Under bending conditions, the Li-dendrite growth can be further aggravated due to bending-induced local plastic deformation and Li-filaments pulverization. Here, the Li-metal anodes are made bending tolerant by integrating Li into bendable scaffolds such as reduced graphene oxide (r-GO) films. In the composites, the bending stress is largely dissipated by the scaffolds. The scaffolds have increased available surface for homogeneous Li plating and minimize volume fluctuation of Li electrodes during cycling. Significantly improved cycling performance under bending conditions is achieved. With the bending-tolerant r-GO/Li-metal anode, bendable lithium–sulfur and lithium–oxygen batteries with long cycling stability are realized. A bendable integrated solar cell–battery system charged by light with stable output and a series connected bendable battery pack with higher voltage is also demonstrated. It is anticipated that this bending-tolerant anode can be combined with further electrolytes and cathodes to develop new bendable energy systems.Bendable energy-storage systems are demanded to power conformal electronics. Lithium-metal batteries have higher energy density than lithium-ion batteries, but they are hindered by the dendrite challenge. Under bending condition, the dendrite growth can be further aggravated due to local plastic deformation and filaments pulverization. Herein, Li-metal anodes that are bending tolerant are made by integrating Li into bendable scaffolds.
      PubDate: 2017-11-10T10:01:02.76556-05:0
      DOI: 10.1002/adma.201703891
       
  • Advanced Plasmonic Materials for Dynamic Color Display
    • Authors: Lei Shao; Xiaolu Zhuo, Jianfang Wang
      Abstract: Plasmonic structures exhibit promising applications in high-resolution and durable color generation. Research on advanced hybrid plasmonic materials that allow dynamically reconfigurable color control has developed rapidly in recent years. Some of these results may give rise to practically applicable reflective displays in living colors with high performance and low power consumption. They will attract broad interest from display markets, compared with static plasmonic color printing, for example, in applications such as digital signage, full-color electronic paper, and electronic device screens. In this progress report, the most promising recent examples of utilizing advanced plasmonic materials for the realization of dynamic color display are highlighted and put into perspective. The performances, advantages, and disadvantages of different technologies are discussed, with emphasis placed on both the potential and possible limitations of various hybrid materials for dynamic plasmonic color display.Dynamically reconfigurable control of plasmonic colors has great potential in the realization of full-color reflective visual displays with high performance and low energy consumption. This progress report provides a focused overview of recent development in utilizing advanced plasmonic materials for the realization of dynamic color displays.
      PubDate: 2017-11-10T09:56:08.744071-05:
      DOI: 10.1002/adma.201704338
       
  • Carbon–Heteroatom Bond Formation by an Ultrasonic Chemical Reaction
           for Energy Storage Systems
    • Authors: Hyun-Tak Kim; HyeonOh Shin, In-Yup Jeon, Masood Yousaf, Jaeyoon Baik, Hae-Won Cheong, Noejung Park, Jong-Beom Baek, Tae-Hyuk Kwon
      Abstract: The direct formation of CN and CO bonds from inert gases is essential for chemical/biological processes and energy storage systems. However, its application to carbon nanomaterials for improved energy storage remains technologically challenging. A simple and very fast method to form CN and CO bonds in reduced graphene oxide (RGO) and carbon nanotubes (CNTs) by an ultrasonic chemical reaction is described. Electrodes of nitrogen- or oxygen-doped RGO (N-RGO or O-RGO, respectively) are fabricated via the fixation between N2 or O2 carrier gas molecules and ultrasonically activated RGO. The materials exhibit much higher capacitance after doping (133, 284, and 74 F g−1 for O-RGO, N-RGO, and RGO, respectively). Furthermore, the doped 2D RGO and 1D CNT materials are prepared by layer-by-layer deposition using ultrasonic spray to form 3D porous electrodes. These electrodes demonstrate very high specific capacitances (62.8 mF cm−2 and 621 F g−1 at 10 mV s−1 for N-RGO/N-CNT at 1:1, v/v), high cycling stability, and structural flexibility.Direct CN and CO bond formation with N2 or O2 gases by chemical reactions in a simple ultrasonic spray process is essential in various carbon nanomaterials. The resulting N-doped carbon nanomaterials display remarkable performance in energy storage applications. Furthermore, the double nozzle system used for ultrasonic deposition can produce a layer-by-layer nitrogen-reduced graphene oxide/nitrogen-doped carbon nanotube multidimensional carbon framework, which further improves the energy storage performance.
      PubDate: 2017-11-09T01:17:37.605868-05:
      DOI: 10.1002/adma.201702747
       
  • Mapping Nanostructural Variations in Silk by Secondary Electron
           Hyperspectral Imaging
    • Authors: Quan Wan; Kerry J. Abrams, Robert C. Masters, Abdullah C. S. Talari, Ihtesham U. Rehman, Frederik Claeyssens, Chris Holland, Cornelia Rodenburg
      Abstract: Nanostructures underpin the excellent properties of silk. Although the bulk nanocomposition of silks is well studied, direct evidence of the spatial variation of nanocrystalline (ordered) and amorphous (disordered) structures remains elusive. Here, secondary electron hyperspectral imaging can be exploited for direct imaging of hierarchical structures in carbon-based materials, which cannot be revealed by any other standard characterization methods. Through applying this technique to silks from domesticated (Bombyx mori) and wild (Antheraea mylitta) silkworms, a variety of previously unseen features are reported, highlighting the local interplay between ordered and disordered structures. This technique is able to differentiate composition on the nanoscale and enables in-depth studies into the relationship between morphology and performance of these complex biopolymer systems.Successful development of hierarchical materials relies on the refined organization of repeat units from the nano- to the microscale. Secondary Electron Hyperspectral Imaging (SEHI) addresses a length-scale characterization gap in carbon materials, and is used to highlight the distribution and variation of order/disorder at the nanoscale in model silk materials, providing insight into natural silk spinning.
      PubDate: 2017-11-08T09:06:17.214252-05:
      DOI: 10.1002/adma.201703510
       
  • Avoiding Energy Loss on TADF Emitters: Controlling the Dual Conformations
           of D–A Structure Molecules Based on the Pseudoplanar Segments
    • Authors: Kai Wang; Cai-Jun Zheng, Wei Liu, Ke Liang, Yi-Zhong Shi, Si-Lu Tao, Chun-Sing Lee, Xue-Mei Ou, Xiao-Hong Zhang
      Abstract: The recent introduction of thermally activated delayed fluorescence (TADF) emitters is regarded as an important breakthrough for the development of high efficiency organic light-emitting devices (OLEDs). The planar D and A groups are generally used to construct TADF emitters for their rigid structure and large steric hindrance. In this work, it is shown that many frequently used nonaromatic (noncontinuous conjugation or without satisfying Hückel's rule) planar segments, such as 9,9-dimethyl-9,10-dihydroacridine, are actually pseudoplanar segments and have two possible conformations–a planar form and a crooked form. Molecules constructed from pseudoplanar segments can thus have two corresponding conformations. Their existence can have significant impact on the performance of many TADF emitters. Two design strategies are presented for addressing the problem by either (1) increasing the rigidity of these groups to suppress its crooked form or (2) increasing the steric hindrance of the linked group to minimize energy of the emitters with the highly twisted form. Following these strategies, two new emitters are synthesized accordingly and successfully applied in OLEDs demonstrating high external quantum efficiencies (20.2% and 18.3%).A schematic energy level diagram of (2-(9,9-dimethylacridin-10(9H)-yl) thianthrene-5,5,10,10-tetraoxide) shows that molecules constructed from pseudoplanar segments can have two corresponding conformations, which have significant impact on the performance of many thermally activated delayed fluorescence emitters. By either increasing the rigidity of these groups, or by increasing the steric hindrance of the linked group, the problem can be addressed.
      PubDate: 2017-11-08T09:05:53.435634-05:
      DOI: 10.1002/adma.201701476
       
  • Inorganic/Organic Double-Network Gels Containing Ionic Liquids
    • Authors: Eiji Kamio; Tomoki Yasui, Yu Iida, Jian Ping Gong, Hideto Matsuyama
      Abstract: Highly robust ion gels, termed double-network (DN) ion gels, composed of inorganic/organic interpenetrating networks and a large amount of ionic liquids (ILs), are fabricated. The DN ion gels with an 80 wt% IL content show extraordinarily high mechanical strength: more than 28 MPa of compressive fracture stress. In the DN ion gel preparation, a brittle inorganic network of physically bonded silica nanoparticles and a ductile organic network of polydimethylacrylamide (PDMAAm) are formed in the IL. Because of the different reaction mechanisms of the inorganic/organic networks, the DN ion gels can be formed by an easy and free-shapeable one-pot synthesis. They can be prepared in a controllable manner by manipulating the formation order of the inorganic and organic networks via not only multistep but also single-step processes. When silica particles form a network prior to the PDMAAm network formation, DN ion gels can be prepared. The brittle silica particle network in the DN ion gel, serving as sacrificial bonds, easily ruptures under loading to dissipate energy, while the ductile PDMAAm network maintains the shape of the material by the rubber elasticity. Given the reversible physical bonding between the silica particles, the DN ion gels exhibit a significant degree of self-recovery by annealing.Robust ion gels with an inorganic/organic double-network (DN) are developed. The DN ion gels that can withstand more than 28 MPa of compressive stress are easily prepared by controlling the formation order of the inorganic and organic networks in a one-pot/one-step process. Recoverable physical bonding in the inorganic network lends to self-healing property of the DN ion gels.
      PubDate: 2017-11-08T01:04:02.092553-05:
      DOI: 10.1002/adma.201704118
       
  • Non-Equilibrium Self-Assembly of Monocomponent and Multicomponent Tubular
           Structures in Rotating Fluids
    • Authors: Taehoon Lee; Konrad Gizynski, Bartosz A. Grzybowski
      Abstract: When suspended in a denser rotating fluid, lighter particles experience a cylindrically symmetric confining potential that drives their crystallization into either monocomponent or unprecedented binary tubular packing. These assemblies form around the fluid's axis of rotation, can be dynamically interconverted (upon accelerating or decelerating the fluid), can exhibit preferred chirality, and can be made permanent by solidifying the fluid. The assembly can be extended to fluids forming multiple concentric interfaces or to systems of bubbles forming both ordered and “gradient” structures within curable polymers.Lighter particles immersed in a denser fluid experience a cylindrically symmetric confining potential. Under the action of this potential, the particles organize into various non-equilibrium tubular structures that can be made permanent by gelating or polymerizing the fluid phase. The tubular structures can exhibit preferred chirality and can undergo dynamic phase transitions when the rotation speed of the fluid is changed.
      PubDate: 2017-11-07T11:44:13.719325-05:
      DOI: 10.1002/adma.201704274
       
  • All-Polymer Solar Cells Based on a Conjugated Polymer Containing
           Siloxane-Functionalized Side Chains with Efficiency over 10%
    • Authors: Baobing Fan; Lei Ying, Peng Zhu, Feilong Pan, Feng Liu, Junwu Chen, Fei Huang, Yong Cao
      Abstract: A novel wide-bandgap conjugated copolymer based on an imide-functionalized benzotriazole building block containing a siloxane-terminated side-chain is developed. This copolymer is successfully used to fabricate highly efficient all-polymer solar cells (all-PSCs) processed at room temperature with the green-solvent 2-methyl-tetrahydrofuran. When paired with a naphthalene diimide-based polymer electron-acceptor, the all-PSC exhibits a maximum power conversion efficiency (PCE) of 10.1%, which is the highest value so far reported for an all-PSC. Of particular interest is that the PCE remains 9.4% after thermal annealing at 80 °C for 24 h. The resulting high efficiency is attributed to a combination of high and balanced bulky charge carrier mobility, favorable face-on orientation, and high crystallinity. These observations indicate that the resulting copolymer can be a promising candidate toward high-performance all-PSCs for practical applications.A novel wide-bandgap conjugated copolymer PTzBI-Si based on an imide-functionalized benzotriazole unit containing a siloxane-terminated side-chain is developed and used to fabricate all-polymer solar cells (all-PSCs). When processed with a green-solvent 2-methyl-tetrahydrofuran, the all-PSC exhibits a power conversion efficiency of 10.1%, which represents the highest efficiency ever reported for all-PSCs.
      PubDate: 2017-11-07T11:42:17.877983-05:
      DOI: 10.1002/adma.201703906
       
  • Perovskite Solar Cells with ZnO Electron-Transporting Materials
    • Authors: Peng Zhang; Jiang Wu, Ting Zhang, Yafei Wang, Detao Liu, Hao Chen, Long Ji, Chunhua Liu, Waseem Ahmad, Zhi David Chen, Shibin Li
      Abstract: Perovskite solar cells (PSCs) have developed rapidly over the past few years, and the power conversion efficiency of PSCs has exceeded 20%. Such high performance can be attributed to the unique properties of perovskite materials, such as high absorption over the visible range and long diffusion length. Due to the different diffusion lengths of holes and electrons, electron transporting materials (ETMs) used in PSCs play a critical role in PSCs performance. As an alternative to TiO2 ETM, ZnO materials have similar physical properties to TiO2 but with much higher electron mobility. In addition, there are many simple and facile methods to fabricate ZnO nanomaterials with low cost and energy consumption. This review focuses on recent developments in the use of ZnO ETM for PSCs. The fabrication methods of ZnO materials are briefly introduced. The influence of different ZnO ETMs on performance of PSCs is then reviewed. The limitations of ZnO ETM-based PSCs and some solutions to these challenges are also discussed. The review provides a systematic and comprehensive understanding of the influence of different ZnO ETMs on PSCs performance and potentially motivates further development of PSCs by extending the knowledge of ZnO-based PSCs to TiO2-based PSCs.Progress in perovskite solar cells based on ZnO electron-transport materials of different morphologies and their fabrication methods is summarized. The influence of the ZnO morphology and fabrication process on the performance of perovskite solar cells are reviewed and highlighted. Moreover, the issues of ZnO materials, and some solutions and strategies to promote the performance of solar cells, are introduced.
      PubDate: 2017-11-06T04:37:19.123635-05:
      DOI: 10.1002/adma.201703737
       
  • Anion-Regulated Selective Generation of Cobalt Sites in Carbon: Toward
           Superior Bifunctional Electrocatalysis
    • Authors: Gang Wan; Ce Yang, Wanpeng Zhao, Qianru Li, Ning Wang, Tao Li, Hua Zhou, Hangrong Chen, Jianlin Shi
      Abstract: The introduction of active transition metal sites (TMSs) in carbon enables the synthesis of noble-metal-free electrocatalysts for clean energy conversion applications; however, there are often multiple existing forms of TMSs, which are of different natures and catalytic models. Regulating the evolution of distinctive TMSs is highly desirable but remains challenging to date. Anions, as essential elements involved in the synthesis, have been totally neglected previously in the construction of TMSs. Herein, the effects of anions on the creation of different types of TMSs are investigated for the first time. It is found that the active cobalt–nitrogen sites tend to be selectively constructed on the surface of N-doped carbon by using chloride, while metallic cobalt nanoparticles encased in protective graphite layers are the dominant forms of cobalt species with nitrate ions. The obtained catalysts demonstrate cobalt-sites-dependent activity for oxygen reduction reaction and hydrogen evolution reaction in acidic media. The remarkably enhanced catalytic activities approaching that of benchmark Pt/C in an acidic medium have been obtained on the catalyst dominated with cobalt–nitrogen sites, confirmed by the advanced spectroscopic characterization. This finding demonstrates a general paradigm of anion-regulated evolution of distinctive TMSs, providing a new pathway for enhancing performances of various targeted reactions related with TMSs.A versatile anion-regulated selectivity generation strategy of transition metal sites (TMSs) is successfully demonstrated via exploring the neglected importance of anions involved in the synthesis. The controlled evolution of cobalt–nitrogen coordination sites on the surface of cobalt nanoparticles within the protective graphite layers in N-doped carbon is achieved, which demonstrates cobalt-site-dependent hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) catalytic performances in acidic media.
      PubDate: 2017-11-06T04:35:31.988345-05:
      DOI: 10.1002/adma.201703436
       
  • Nanofluidics: A New Arena for Materials Science
    • Authors: Yan Xu
      Abstract: A significant growth of research in nanofluidics is achieved over the past decade, but the field is still facing considerable challenges toward the transition from the current physics-centered stage to the next application-oriented stage. Many of these challenges are associated with materials science, so the field of nanofluidics offers great opportunities for materials scientists to exploit. In addition, the use of unusual effects and ultrasmall confined spaces of well-defined nanofluidic environments would offer new mechanisms and technologies to manipulate nanoscale objects as well as to synthesize novel nanomaterials in the liquid phase. Therefore, nanofluidics will be a new arena for materials science. In the past few years, burgeoning progress has been made toward this trend, as overviewed in this article, including materials and methods for fabricating nanofluidic devices, nanofluidics with functionalized surfaces and functional material components, as well as nanofluidics for manipulating nanoscale materials and fabricating new nanomaterials. Many critical challenges as well as fantastic opportunities in this arena lie ahead. Some of those, which are of particular interest, are also discussed.The use of nanofluidics opens up a new arena for materials science. Burgeoning progress is made, including new materials and methods for fabricating nanofluidic devices, nanofluidics with functionalized surfaces and functional material components, as well as nanofluidics for manipulating nanoscale materials and fabricating new nanomaterials.
      PubDate: 2017-11-02T02:23:27.289875-05:
      DOI: 10.1002/adma.201702419
       
  • Wafer-Scale Synthesis of Reliable High-Mobility Molybdenum Disulfide Thin
           Films via Inhibitor-Utilizing Atomic Layer Deposition
    • Authors: Woojin Jeon; Yeonchoo Cho, Sanghyun Jo, Ji-Hoon Ahn, Seong-Jun Jeong
      Abstract: A reliable and rapid manufacturing process of molybdenum disulfide (MoS2) with atomic-scale thicknesses remains a fundamental challenge toward its successful incorporation into high-performance nanoelectronics. It is imperative to achieve rapid and scalable production of MoS2 exhibiting high carrier mobility and excellent on/off current ratios simultaneously. Herein, inhibitor-utilizing atomic layer deposition (iALD) is presented as a novel method to meet these requirements at the wafer scale. The kinetics of the chemisorption of Mo precursors in iALD is governed by the reaction energy and the steric hindrance of inhibitor molecules. By optimizing the inhibition of Mo precursor absorption, the nucleation on the substrate in the initial stage can be spontaneously tailored to produce iALD-MoS2 thin films with a significantly increased grain size and surface coverage (>620%). Moreover, highly crystalline iALD-MoS2 thin films, with thicknesses of only a few layers, excellent room temperature mobility (13.9 cm2 V−1 s−1), and on/off ratios (>108), employed as the channel material in field effect transistors on 6″ wafers, are successfully prepared.High-mobility MoS2 thin films with inhibitor-utilizing-atomic layer deposition (iALD) are successfully demonstrated in a wafer scale. As a reliable and rapid manufacturing process, MoS2-iALD, based on the kinetics of Mo precursor adsorption, enables extraordinary grain growth and surface coverage, leading to an excellent room-temperature mobility (13.9 cm2 V−1 s−1) and on/off ratios (>108), as a channel material in a field effect transistor.
      PubDate: 2017-11-02T02:21:16.525814-05:
      DOI: 10.1002/adma.201703031
       
  • Flexible Gallium Nitride for High-Performance, Strainable Radio-Frequency
           Devices
    • Authors: Nicholas R. Glavin; Kelson D. Chabak, Eric R. Heller, Elizabeth A. Moore, Timothy A. Prusnick, Benji Maruyama, Dennis E. Walker, Donald L. Dorsey, Qing Paduano, Michael Snure
      Abstract: Flexible gallium nitride (GaN) thin films can enable future strainable and conformal devices for transmission of radio-frequency (RF) signals over large distances for more efficient wireless communication. For the first time, strainable high-frequency RF GaN devices are demonstrated, whose exceptional performance is enabled by epitaxial growth on 2D boron nitride for chemical-free transfer to a soft, flexible substrate. The AlGaN/GaN heterostructures transferred to flexible substrates are uniaxially strained up to 0.85% and reveal near state-of-the-art values for electrical performance, with electron mobility exceeding 2000 cm2 V−1 s−1 and sheet carrier density above 1.07 × 1013 cm−2. The influence of strain on the RF performance of flexible GaN high-electron-mobility transistor (HEMT) devices is evaluated, demonstrating cutoff frequencies and maximum oscillation frequencies greater than 42 and 74 GHz, respectively, at up to 0.43% strain, representing a significant advancement toward conformal, highly integrated electronic materials for RF applications.Flexible gallium nitride (GaN) thin films and devices are described that enable amplification of radio-frequency signals in future conformal and wearable electronics. Flexible GaN is realized through lift-off using a 2D boron nitride release layer and can accommodate strains up to 0.43%, while exhibiting electron mobility and small signal frequency performance rivaling high-performing, rigid GaN materials.
      PubDate: 2017-11-02T02:20:46.223181-05:
      DOI: 10.1002/adma.201701838
       
  • “Electro-Typing” on a Carbon-Nanoparticles-Filled Polymeric Film using
           Conducting Atomic Force Microscopy
    • Authors: Sumita Goswami; Suman Nandy, Arghya Narayan Banerjee, Asal Kiazadeh, Gowra Raghupathy Dillip, Joana V. Pinto, Sang Woo Joo, Rodrigo Martins, Elvira Fortunato
      Abstract: Next-generation electrical nanoimprinting of a polymeric data sheet based on charge trapping phenomena is reported here. Carbon nanoparticles (CNPs) (waste carbon product) are deployed into a polymeric matrix (polyaniline) (PANI) as a charge trapping layer. The data are recorded on the CNPs-filled polyaniline device layer by “electro-typing” under a voltage pulse (VET, from ±1 to ±7 V), which is applied to the device layer through a localized charge-injection method. The core idea of this device is to make an electrical image through the charge trapping mechanism, which can be “read” further by the subsequent electrical mapping. The density of stored charges at the carbon–polyaniline layer, near the metal/polymer interface, is found to depend on the voltage amplitude, i.e., the number of injected charge carriers. The relaxation of the stored charges is studied by different probe voltages and for different devices, depending on the percolation of the CNPs into the PANI. The polymeric data sheet retains the recorded data for more than 6 h, which can be refreshed or erased at will. Also, a write–read–erase–read cycle is performed for the smallest “bit” of stored information through a single contact between the probe and the device layer.Carbon nanoparticles (CNPs) are deployed into a polymeric matrix (polyaniline) as charge trapping sites, which function toward the concept of non-destructive “electro-typed” organic data-storage devices. The dynamics of the localized electronic transport mechanism of a CNPs-incorporated polyaniline (PANI) composite layer are demonstrated using atomic force microscopy.
      PubDate: 2017-11-02T02:18:36.878433-05:
      DOI: 10.1002/adma.201703079
       
  • Oxygen Vacancies Dominated NiS2/CoS2 Interface Porous Nanowires for
           Portable Zn–Air Batteries Driven Water Splitting Devices
    • Authors: Jie Yin; Yuxuan Li, Fan Lv, Min Lu, Ke Sun, Wei Wang, Lei Wang, Fangyi Cheng, Yefei Li, Pinxian Xi, Shaojun Guo
      Abstract: The development of highly active and stable oxygen evolution reaction (OER) electrocatalysts is crucial for improving the efficiency of water splitting and metal–air battery devices. Herein, an efficient strategy is demonstrated for making the oxygen vacancies dominated cobalt–nickel sulfide interface porous nanowires (NiS2/CoS2–O NWs) for boosting OER catalysis through in situ electrochemical reaction of NiS2/CoS2 interface NWs. Because of the abundant oxygen vacancies and interface porous nanowires structure, they can catalyze the OER efficiently with a low overpotential of 235 mV at j = 10 mA cm−2 and remarkable long-term stability in 1.0 m KOH. The home-made rechargeable portable Zn–air batteries by using NiS2/CoS2–O NWs as the air–cathode display a very high open-circuit voltage of 1.49 V, which can maintain for more than 30 h. Most importantly, a highly efficient self-driven water splitting device is designed with NiS2/CoS2–O NWs as both anode and cathode, powered by two-series-connected NiS2/CoS2–O NWs-based portable Zn–air batteries. The present work opens a new way for designing oxygen vacancies dominated interface nanowires as highly efficient multifunctional electrocatalysts for electrochemical reactions and renewable energy devices.A self-driven water splitting device is fabricated by using the oxygen vacancies dominated cobalt–nickel sulfide interface porous nanowires (NiS2/CoS2–O NWs) as both anode and cathode, and powered by two-series-connected NiS2/CoS2–O NWs-based portable Zn–air batteries.
      PubDate: 2017-11-02T02:17:51.264561-05:
      DOI: 10.1002/adma.201704681
       
  • Nanoparticulate Delivery of Cancer Cell Membrane Elicits Multiantigenic
           Antitumor Immunity
    • Authors: Ashley V. Kroll; Ronnie H. Fang, Yao Jiang, Jiarong Zhou, Xiaoli Wei, Chun Lai Yu, Jie Gao, Brian T. Luk, Diana Dehaini, Weiwei Gao, Liangfang Zhang
      Abstract: Anticancer vaccines train the body's own immune system to recognize and eliminate malignant cells based on differential antigen expression. While conceptually attractive, clinical efficacy is lacking given several key challenges stemming from the similarities between cancerous and healthy tissue. Ideally, an effective vaccine formulation would deliver multiple tumor antigens in a fashion that potently stimulates endogenous immune responses against those antigens. Here, it is reported on the fabrication of a biomimetic, nanoparticulate anticancer vaccine that is capable of delivering autologously derived tumor antigen material together with a highly immunostimulatory adjuvant. The two major components, tumor antigens and adjuvant, are presented concurrently in a fashion that maximizes their ability to promote effective antigen presentation and activation of downstream immune processes. Ultimately, it is demonstrated that the formulation can elicit potent antitumor immune responses in vivo. When combined with additional immunotherapies such as checkpoint blockades, the nanovaccine demonstrates substantial therapeutic effect. Overall, the work represents the rational application of nanotechnology for immunoengineering and can provide a blueprint for the future development of personalized, autologous anticancer vaccines with broad applicability.A biomimetic, nanoparticulate anticancer vaccine is fabricated by coating membrane derived from cancer cells onto an immunostimulatory core. The resulting nanoformulation can promote immunity against multiple tumor antigens. When the nanovaccine is combined with checkpoint blockade therapy, significant control of tumor growth is achieved. This approach may ultimately be adapted toward designing potent autologous vaccines made from patient-derived tumor material.
      PubDate: 2017-11-02T02:17:24.929334-05:
      DOI: 10.1002/adma.201703969
       
  • Engineering Contactless Particle–Particle Interactions in Active
           Microswimmers
    • Authors: Amir Nourhani; Daniel Brown, Nicholas Pletzer, John G. Gibbs
      Abstract: Artificial self-propelled colloidal particles have recently served as effective building blocks for investigating many dynamic behaviors exhibited by nonequilibrium systems. However, most studies have relied upon excluded volume interactions between the active particles. Experimental systems in which the mobile entities interact over long distances in a well-defined and controllable manner are valuable so that new modes of multiparticle dynamics can be studied systematically in the laboratory. Here, a system of self-propelled microscale Janus particles is engineered to have contactless particle–particle interactions that lead to long-range attraction, short-range repulsion, and mutual alignment between adjacent swimmers. The unique modes of motion that arise can be tuned by modulating the system's parameters.A system is presented in which self-propelled active colloidal particles interact in a contactless manner. These swimmers demonstrate both long-range attraction and short-range repulsion resulting from chemical propulsion and magnetic dipole–dipole interactions. Unique modes of motion arise including contactless cargo delivery, chasing behavior, as well as reconfigurable clusters that easily change morphology due to the contactless nature of the interactions.
      PubDate: 2017-11-02T02:16:43.543443-05:
      DOI: 10.1002/adma.201703910
       
  • Antiferromagnetic Pyrite as the Tumor Microenvironment-Mediated
           Nanoplatform for Self-Enhanced Tumor Imaging and Therapy
    • Authors: Zhongmin Tang; Huilin Zhang, Yanyan Liu, Dalong Ni, Hua Zhang, Jiawen Zhang, Zhenwei Yao, Mingyuan He, Jianlin Shi, Wenbo Bu
      Abstract: Several decades of research have identified the specific tumor microenvironment (TME) to develop promising nanotheranostics, such as pH-sensitive imaging, acidity-sensitive starving therapy, and hydrogen peroxide-activated chemotherapy, etc. Herein, a novel TME-mediated nanoplatform employing antiferromagnetic pyrite nanocubes is presented, exploiting the intratumoral, overproduced peroxide for self-enhanced magnetic resonance imaging (MRI) and photothermal therapy (PTT)/chemodynamic therapy (CDT). Through the activation of excessive peroxide in the tumor microenvironment, pyrite can lead to in situ surface oxidation and generate hydroxyl radicals to kill tumor cells (i.e., CDT). The increase of the valence state of surface Fe significantly promotes the performance of MRI accompanied by CDT. Furthermore, the localized heat by photothermal treatment can accelerate the intratumoral Fenton process, enabling a synergetic PTT/CDT. To our best knowledge, this is the first study to use the TME-response valence-variable strategy based on pyrite for developing a synergetic nanotheranostic, which will open up a new dimension for the design of other TME-based anticancer strategies.Herein an innovative tumor microenvironment-mediated nanoplatform for self-enhanced magnetic resonance imaging and chemodynamic therapy/photothermal therapy is developed.
      PubDate: 2017-11-02T02:12:05.410747-05:
      DOI: 10.1002/adma.201701683
       
  • Hierarchically Nanostructured 1D Conductive Bundle Yarn-Based
           Triboelectric Nanogenerators
    • Authors: Won Bae Ko; Da Song Choi, Choong Hyun Lee, Jung Yup Yang, Gap Soo Yoon, Jin Pyo Hong
      Abstract: Wearable 2D textile platforms are the subject of intense focus to promote the creation of outstanding added value for textile-based applications in consumer electronics, energy harvesting, and storage. In particular, 2D textile-based energy harvesters from the living environment of human motions exhibit insufficient geometry deformation and low current density, thereby providing low power generation. Therefore, a unique starting point in this work is the use of 1D conductive bundle yarn (1D CBY) as a generic step for the development of 1D CBY-based energy harvesters through a weaving technology. The performance of 1D CBY-based triboelectric nanogenerators (1D CBY-TENGs) is addressed through contact electrification between the arrays of nanostructured 1D CBYs and 2D conductive fabric serving as tribomaterials. The manipulation of hierarchically nanostructured surfaces on the 1D CBYs by the hydrothermal process represents one of the crucial approaches of enhancing power generation through a large contact surface area. The 1D CBY-TENGs with a variation in the number of 1D CBY and stack configurations are also tested as a simple integration scheme, confirming the expected 1D CBY number and stack dependency in the output performance.1D conductive bundle yarn-based triboelectric nanogenerators (1D CBY-TENGs) are designed to build a new class of wearable energy harvester operated by human motions. Hierarchically nanostructured 1D CBY-TENGs would lead to a breakthrough in wearable textile electronics and open up the field for a much broader range of free-form factor by weaving 1D yarn onto various 2D/3D textile networks.
      PubDate: 2017-10-31T02:16:19.274333-05:
      DOI: 10.1002/adma.201704434
       
  • Preparation of High-Performance Ionogels with Excellent Transparency, Good
           Mechanical Strength, and High Conductivity
    • Authors: Yi Ding; Jiajing Zhang, Li Chang, Xiqi Zhang, Hongliang Liu, Lei Jiang
      Abstract: Ionogels offer great potential for diverse electric applications. However, it remains challenging to fabricate high-performance ionogels with both good mechanical strength and high conductivity. Here, a new kind of transparent ionogel with both good mechanical strength and high conductivity is designed via locking a kind of free ionic liquid (IL), i.e., 1-ethyl-3-methylimidazolium dicyanamide ([EMIm][DCA]), into charged poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS)-based double networks. On the one hand, the charged PAMPS double network provides good mechanical strength and excellent recovery property. On the other hand, the free [EMIm][DCA] locked in the charged double network through electrostatic interaction offers ionic conductivity as high as ≈1.7–2.4 S m−1 at 25 °C. It is demonstrated that the designed ionogel can be successfully used for a flexible skin sensor even under harsh conditions. Considering the rationally designed chemical structures of ILs and the diversity of charged polymer networks, it is envisioned that this strategy can be extended to a broad range of polymer systems. Moreover, functional components such as conducting polymers, 0D nanoparticles, 1D nanowires, and 2D nanosheets can be introduced into the polymer systems to fabricate diverse novel ionogels with unique functions. It is believed that this design principle will provide a new opportunity to construct next-generation multifunctional ionogels.A new kind of transparent ionogel with both good mechanical strength and high conductivity is prepared via locking a kind of free ionic liquid, 1-ethyl-3-methylimidazolium dicyanamide, in charged poly(2-acrylamido-2-methyl-1-propanesulfonic acid)-based double networks through electrostatic interactions. The ionogel possesses long-term stability and relatively high conductivity in a wide temperature range and under vacuum, which makes the ionogel suitable as a sensor device under extreme conditions.
      PubDate: 2017-10-30T07:49:28.326978-05:
      DOI: 10.1002/adma.201704253
       
  • Iridium-Based Multimetallic Porous Hollow Nanocrystals for Efficient
           Overall-Water-Splitting Catalysis
    • Authors: Jianrui Feng; Fan Lv, Weiyu Zhang, Peihao Li, Kai Wang, Chao Yang, Bin Wang, Yong Yang, Jinhui Zhou, Fei Lin, Gui-Chang Wang, Shaojun Guo
      Abstract: The development of active and durable bifunctional electrocatalysts for overall water splitting is mandatory for renewable energy conversion. This study reports a general method for controllable synthesis of a class of IrM (M = Co, Ni, CoNi) multimetallic porous hollow nanocrystals (PHNCs), through etching Ir-based, multimetallic, solid nanocrystals using Fe3+ ions, as catalysts for boosting overall water splitting. The Ir-based multimetallic PHNCs show transition-metal-dependent bifunctional electrocatalytic activities for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in acidic electrolyte, with IrCo and IrCoNi PHNCs being the best for HER and OER, respectively. First-principles calculations reveal a ligand effect, induced by alloying Ir with 3d transition metals, can weaken the adsorption energy of oxygen intermediates, which is the key to realizing much-enhanced OER activity. The IrCoNi PHNCs are highly efficient in overall-water-splitting catalysis by showing a low cell voltage of only 1.56 V at a current density of 2 mA cm−2, and only 8 mV of polarization-curve shift after a 1000-cycle durability test in 0.5 m H2SO4 solution. This work highlights a potentially powerful strategy toward the general synthesis of novel, multimetallic, PHNCs as highly active and durable bifunctional electrocatalysts for high-performance electrochemical overall-water-splitting devices.A class of Ir-based, multimetallic, porous hollow nanocrystals is synthesized using a general method through the use of Fe3+ ions to etch Ir-based solid nanocrystals, as highly efficient, bifunctional catalysts for boosting overall-water-splitting catalysis.
      PubDate: 2017-10-30T07:48:49.184172-05:
      DOI: 10.1002/adma.201703798
       
  • Recent Progress on Antimonene: A New Bidimensional Material
    • Authors: Pablo Ares; Juan José Palacios, Gonzalo Abellán, Julio Gómez-Herrero, Félix Zamora
      Abstract: Antimonene, defined in sensu stricto as a single layer of antimony atoms, is recently the focus of numerous theoretical works predicting a variety of interesting properties and is quickly attracting the attention of the scientific community. However, what places antimonene in a different category from other 2D crystals is its strong spin–orbit coupling and a drastic evolution of its properties from the monolayer to the few-layer system. The recent isolation of this novel 2D material pushes the interest for antimonene even further. Here, a review of both theoretical predictions and experimental results is compiled. First, an account of the calculations anticipating an electronic band structure suitable for optoelectronics and thermoelectric applications in monolayer form and a topological semimetal in few-layer form is given. Second, the different approaches to produce antimonene—mechanical and liquid phase exfoliation, and epitaxial growth methods—are reviewed. In addition, this work also reports the main characterization techniques used to study this exotic material. This review provides insights for further exploring the appealing properties of antimonene and puts forward the opportunities and challenges for future applications from (opto)electronic device fabrication to biomedicine.Antimonene, a single layer of antimony atoms, is a promising 2D material with potential applications in a variety of technological fields, including optoelectronics and energy harvesting. Recently, the isolation of a single layer of antimonene has opened the door to the possibility of realizing these predictions. In this work, recent progresses on antimonene are reviewed.
      PubDate: 2017-10-27T07:19:14.483864-05:
      DOI: 10.1002/adma.201703771
       
  • Graphene-Armored Aluminum Foil with Enhanced Anticorrosion Performance as
           Current Collectors for Lithium-Ion Battery
    • Authors: Mingzhan Wang; Miao Tang, Shulin Chen, Haina Ci, Kexin Wang, Liurong Shi, Li Lin, Huaying Ren, Jingyuan Shan, Peng Gao, Zhongfan Liu, Hailin Peng
      Abstract: Aluminum (Al) foil, as the most accepted cathode current collector for lithium-ion batteries (LIBs), is susceptible to local anodic corrosions during long-term operations. Such corrosions could lead to the deterioration or even premature failure of the batteries and are generally believed to be a bottleneck for next-generation 5 V LIBs. Here, it is demonstrated that Al foil armored by conformal graphene coating exhibits significantly reinforced anodic corrosion resistance in both LiPF6 and lithium bis(trifluoromethanesulphonyl) imide (LiTFSI) based electrolytes. Moreover, LiMn2O4 cells using graphene-armored Al foil as current collectors (LMO/GA) demonstrate enhanced electrochemical performance in comparison with those using pristine Al foil (LMO/PA). The long-term discharge capacity retention of LMO/GA cell after ≈950 h straight operations at low rate (0.5 C) reaches up to 91%, remarkably superior to LMO/PA cell (75%). The self-discharge propensity of LMO/GA is clearly relieved and the rate/power performance is also improved with graphene mediations. This work not only contributes to the long-term stable operations of LIBs but also might catalyze the deployment of 5 V LIBs in the future.Conformal multilayer graphene films are synthesized onto aluminum (Al) foil via plasma-enhanced chemical vapor deposition to reinforce its anti-anodic corrosion performance. Thanks to its enhanced anti-anodic corrosion property, cells utilizing graphene-armored Al foil as cathode current collectors show remarkably improved long-term cycling stability and relieved self-discharge propensity. Moreover, cell's rate/power performance is also boosted with the mediation of graphene.
      PubDate: 2017-10-27T02:31:33.969862-05:
      DOI: 10.1002/adma.201703882
       
  • Nanoscale Manipulation of Spinel Lithium Nickel Manganese Oxide Surface by
           Multisite Ti Occupation as High-Performance Cathode
    • Authors: Biwei Xiao; Hanshuo Liu, Jian Liu, Qian Sun, Biqiong Wang, Karthikeyan Kaliyappan, Yang Zhao, Mohammad Norouzi Banis, Yulong Liu, Ruying Li, Tsun-Kong Sham, Gianluigi A. Botton, Mei Cai, Xueliang Sun
      Abstract: A novel two-step surface modification method that includes atomic layer deposition (ALD) of TiO2 followed by post-annealing treatment on spinel LiNi0.5Mn1.5O4 (LNMO) cathode material is developed to optimize the performance. The performance improvement can be attributed to the formation of a TiMn2O4 (TMO)-like spinel phase resulting from the reaction of TiO2 with the surface LNMO. The Ti incorporation into the tetrahedral sites helps to combat the impedance growth that stems from continuous irreversible structural transition. The TMO-like spinel phase also alleviates the electrolyte decomposition during electrochemical cycling. 25 ALD cycles of TiO2 growth are found to be the optimized parameter toward capacity, Coulombic efficiency, stability, and rate capability enhancement. A detailed understanding of this surface modification mechanism has been demonstrated. This work provides a new insight into the atomic-scale surface structural modification using ALD and post-treatment, which is of great importance for the future design of cathode materials.A novel method that combines atomic layer deposition of TiO2 and post-annealing has been developed to fully exploit the performance of LiNi0.5Mn1.5O4. The incorporation of Ti into both the tetrahedral and octahedral sites in the spinel structure suppresses the irreversible surface phase transition during initial charge and contributes to improved performance under both room temperature and 55 °C.
      PubDate: 2017-10-27T02:31:10.585627-05:
      DOI: 10.1002/adma.201703764
       
  • Extremely Vivid, Highly Transparent, and Ultrathin Quantum Dot
           Light-Emitting Diodes
    • Authors: Moon Kee Choi; Jiwoong Yang, Dong Chan Kim, Zhaohe Dai, Junhee Kim, Hyojin Seung, Vinayak S. Kale, Sae Jin Sung, Chong Rae Park, Nanshu Lu, Taeghwan Hyeon, Dae-Hyeong Kim
      Abstract: Displaying information on transparent screens offers new opportunities in next-generation electronics, such as augmented reality devices, smart surgical glasses, and smart windows. Outstanding luminance and transparency are essential for such “see-through” displays to show vivid images over clear background view. Here transparent quantum dot light-emitting diodes (Tr-QLEDs) are reported with high brightness (bottom: ≈43 000 cd m−2, top: ≈30 000 cd m−2, total: ≈73 000 cd m−2 at 9 V), excellent transmittance (90% at 550 nm, 84% over visible range), and an ultrathin form factor (≈2.7 µm thickness). These superb characteristics are accomplished by novel electron transport layers (ETLs) and engineered quantum dots (QDs). The ETLs, ZnO nanoparticle assemblies with ultrathin alumina overlayers, dramatically enhance durability of active layers, and balance electron/hole injection into QDs, which prevents nonradiative recombination processes. In addition, the QD structure is further optimized to fully exploit the device architecture. The ultrathin nature of Tr-QLEDs allows their conformal integration on various shaped objects. Finally, the high resolution patterning of red, green, and blue Tr-QLEDs (513 pixels in.−1) shows the potential of the full-color transparent display.Extremely bright, transparent, and ultrathin quantum dot light-emitting diodes are achieved by engineering electron transport layer and quantum dots, which leads to the highest luminance (bottom: ≈43 000 cd m−2, top: ≈30 000 cd m−2 at 9 V) and transparency (90% at 550 nm) among all types of transparent displays. The ultrathin transparent quantum dot light-emitting diodes can also conformally be integrated on various curvilinear surfaces.
      PubDate: 2017-10-25T10:17:10.237595-05:
      DOI: 10.1002/adma.201703279
       
  • In Situ Coupling Strategy for the Preparation of FeCo Alloys and Co4N
           Hybrid for Highly Efficient Oxygen Evolution
    • Authors: Xiang Zhu; Tian Jin, Chengcheng Tian, Chenbao Lu, Xiaoming Liu, Min Zeng, Xiaodong Zhuang, Shize Yang, Lin He, Honglai Liu, Sheng Dai
      Abstract: An in situ coupling approach is developed to create a new highly efficient and durable cobalt-based electrocatalyst for the oxygen evolution reaction (OER). Using a novel cyclotetramerization, a task-specific bimetallic phthalocyanine-based nanoporous organic framework is successfully built as a precursor for the carbonization synthesis of a nonprecious OER electrocatalyst. The resultant material exhibits an excellent OER activity with a low overpotential of 280 mV at a current density of 10 mA cm−2 and high durability in an alkaline medium. This impressive result ranks among the best from known Co-based OER catalysts under the same conditions. The simultaneous installation of multiple diverse cobalt-based active sites, including FeCo alloys and Co4N nanoparticles, plays a critical role in achieving this promising OER performance. This innovative approach not only enables high-performance OER activity to be achieved but simultaneously provides a means to control the surface features, thereby tuning the catalytic property of the material.A new highly efficient and durable cobalt-based oxygen evolution reaction (OER) electrocatalyst is developed by an in situ coupling approach. A bimetallic phthalocyanine-based framework is built for the construction of the desirable catalyst. The material exhibits an excellent OER activity with a low overpotential of 280 mV at 10 mA cm−2 and high durability in an alkaline medium.
      PubDate: 2017-10-25T10:16:30.723577-05:
      DOI: 10.1002/adma.201704091
       
  • Vertical Growth of 2D Amorphous FePO4 Nanosheet on Ni Foam: Outer and
           Inner Structural Design for Superior Water Splitting
    • Authors: Lei Yang; Zenglong Guo, Jing Huang, Yaoning Xi, Rongjie Gao, Ge Su, Wei Wang, Lixin Cao, Bohua Dong
      Abstract: Rational design of highly efficient bifunctional electrocatalysts based on 3D transition-metal-based materials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is of great importance for sustainable energy conversion processes. Herein, a novel strategy involving outer and inner structural engineering is developed for superior water splitting via in situ vertical growth of 2D amorphous FePO4 nanosheets on Ni foam (Am FePO4/NF). Careful experiments and density functional theory calculations show that the inner and outer structural engineering contributing to the synergistic effects of 2D morphology, amorphous structure, conductive substrate, and Ni−Fe mixed phosphate lead to superior electrocatalytic activity toward OER and HER. Furthermore, a two-electrode electrolyzer assembled using Am FePO4/NF as an electrocatalyst at both electrodes gives current densities of 10 and 100 mA cm−2 at potentials of 1.54 and 1.72 V, respectively, which is comparable to the best bifunctional electrocatalyst reported in the literature. The strategies, introduced in the present work, may open new opportunities for the rational design of other 3D transition-metal-based electrocatalyst through an outer and inner structural control to strengthen the electrocatalytic performance.A novel strategy involving outer and inner structural engineering is developed for superior water splitting via in situ vertical growth of 2D amorphous nanosheets on Ni foam. This structural engineering contributing to the synergistic effect of 2D morphology, amorphous structure, and conductive substrate maps out a promising strategy for further improving catalytic activity of 3D transition-metal-based materials.
      PubDate: 2017-10-25T10:15:54.257337-05:
      DOI: 10.1002/adma.201704574
       
  • Granular Nanostructure: A Facile Biomimetic Strategy for the Design of
           Supertough Polymeric Materials with High Ductility and Strength
    • Authors: Pingan Song; Zhiguang Xu, Matthew S. Dargusch, Zhi-Gang Chen, Hao Wang, Qipeng Guo
      Abstract: The realization of high strength, large ductility, and great toughness for polymeric materials is a vital factor for practical applications in industry. Unfortunately, until now this remains a huge challenge due to the common opposing trends that exist when promoting improvements in these properties using materials design strategies. In the natural world, the cuticle of mussel byssus exhibits a breaking strain as high as 100%, which is revealed to arise from an architectural granular microphase-separated structure within the protein matrix. Herein, a facile biomimetic designed granular nanostructured polymer film is reported. Such biomimetic nanostructured polymer films show a world-record toughness of 122 (± 6.1) J g−1 as compared with other polyvinyl alcohol films, with a breaking strain as high as 205% and a high tensile strength of 91.2 MPa, which is much superior to those of most engineering plastics. This portfolio of outstanding properties can be attributed to the unique nanoscale granular phase-separated structure of this material. These biomimetic designed polymer films are expected to find promising applications in tissue engineering and biomaterials fields, such as artificial skin and tendon, which opens up an innovative methodology for the design of robust polymer materials for a range of innovative future applications.Creating advanced polymers with the desired combination of high strength, great toughness, and large ductility is very challenging due to mutual exclusion between these performances. High-performance polymer films combining exceptional toughness, large ductility, and high strength are successfully created through the design of a granular phase-separated nanostructure by mimicking the attractive microstructure of the cuticle of mussel byssus.
      PubDate: 2017-10-25T10:14:33.235033-05:
      DOI: 10.1002/adma.201704661
       
  • Diatom-Inspired Silica Nanostructure Coatings with Controllable
           Microroughness Using an Engineered Mussel Protein Glue to Accelerate Bone
           Growth on Titanium-Based Implants
    • Authors: Yun Kee Jo; Bong-Hyuk Choi, Chang Sup Kim, Hyung Joon Cha
      Abstract: Silica nanoparticles (SiNPs) have been utilized to construct bioactive nanostructures comprising surface topographic features and bioactivity that enhances the activity of bone cells onto titanium-based implants. However, there have been no previous attempts to create microrough surfaces based on SiNP nanostructures even though microroughness is established as a characteristic that provides beneficial effects in improving the biomechanical interlocking of titanium implants. Herein, a protein-based SiNP coating is proposed as an osteopromotive surface functionalization approach to create microroughness on titanium implant surfaces. A bioengineered recombinant mussel adhesive protein fused with a silica-precipitating R5 peptide (R5-MAP) enables direct control of the microroughness of the surface through the multilayer assembly of SiNP nanostructures under mild conditions. The assembled SiNP nanostructure significantly enhances the in vitro osteogenic cellular behaviors of preosteoblasts in a roughness-dependent manner and promotes the in vivo bone tissue formation on a titanium implant within a calvarial defect site. Thus, the R5-MAP-based SiNP nanostructure assembly could be practically applied to accelerate bone-tissue growth to improve the stability and prolong the lifetime of medical implantable devices.A diatom-inspired silica nanostructure coating with controllable microroughness is exploited through the multilayer assembly of an organic–inorganic composite based on an engineered silica-forming mussel adhesive protein. This novel silica coating positively modulates osteogenic cellular behaviors on underlying substrates by controlling the surface-roughness-dependent osteoconductivity and osteoinductivity, thereby accelerating bone-tissue growth on titanium implants.
      PubDate: 2017-10-25T10:14:02.89321-05:0
      DOI: 10.1002/adma.201704906
       
  • Light Robots: Bridging the Gap between Microrobotics and Photomechanics in
           Soft Materials
    • Authors: Hao Zeng; Piotr Wasylczyk, Diederik S. Wiersma, Arri Priimagi
      Abstract: For decades, roboticists have focused their efforts on rigid systems that enable programmable, automated action, and sophisticated control with maximal movement precision and speed. Meanwhile, material scientists have sought compounds and fabrication strategies to devise polymeric actuators that are small, soft, adaptive, and stimuli-responsive. Merging these two fields has given birth to a new class of devices—soft microrobots that, by combining concepts from microrobotics and stimuli-responsive materials research, provide several advantages in a miniature form: external, remotely controllable power supply, adaptive motion, and human-friendly interaction, with device design and action often inspired by biological systems. Herein, recent progress in soft microrobotics is highlighted based on light-responsive liquid-crystal elastomers and polymer networks, focusing on photomobile devices such as walkers, swimmers, and mechanical oscillators, which may ultimately lead to flying microrobots. Finally, self-regulated actuation is proposed as a new pathway toward fully autonomous, intelligent light robots of the future.Light-controlled soft microrobotics is a nascent field that explores technologies bridging the gap between microrobotics and polymeric artificial muscles. Recent progress in photomobile devices based on liquid-crystal elastomers is highlighted, such as walkers, swimmers, and oscillators, which may ultimately lead to flying microrobots. Self-regulating mechanisms are introduced as a potential route toward intelligent, light-driven microrobotics.
      PubDate: 2017-10-25T02:12:16.60256-05:0
      DOI: 10.1002/adma.201703554
       
  • Giant Polarization Sustainability in Ultrathin Ferroelectric Films
           Stabilized by Charge Transfer
    • Authors: Sirui Zhang; Yinlian Zhu, Yunlong Tang, Ying Liu, Shuang Li, Mengjiao Han, Jinyuan Ma, Bo Wu, Zuhuang Chen, Sahar Saremi, Xiuliang Ma
      Abstract: Ferroelectricity is generally deteriorated or even vanishes when the ferroelectric films are downsized to unit cell scale. To maintain and enhance the polarization in nanoscale ferroelectrics are of scientific and technological importance. Here, giant polarization sustainability is reported in a series of ultrathin PbTiO3 films scaled down to three unit cells grown on NdGaO3(110) substrates with La0.7Sr0.3MnO3 as bottom electrodes. Atomic mappings via aberration-corrected scanning transmission electron microscopy demonstrate the robust ferroelectricity for the sub-10 nm thick film. For the 1.2 nm thick film, the polarization reaches ≈50 µC cm−2. The 2 nm thick film possesses a polarization as high as the bulk value. The films ranging from 10 to 35 nm display a giant elongation of out-of-plane lattice parameter, which corresponds to a polarization of 100 µC cm−2, 20% larger than that of the bulk PbTiO3. The giant enhancement of polarization in the present films is proposed to result from the charge transfer at the La0.7Sr0.3MnO3/PbTiO3 interface, as supported by the anomalous decrease of Mn valence measured from X-ray photoelectron spectroscopy. These results reveal the significant role of charge transfer at interfaces in improving large polarizations in ultrathin ferroelectrics and are meaningful for the development of future electronic devices.A series of ultrathin PbTiO3 films is grown on La0.7Sr0.3MnO3 buffered NdGaO3(110) substrates. Cs-corrected scanning transmission electron microscopy demonstrates the ferroelectricity for the 1.2 nm thick film with the polarization of ≈50 µC cm−2. The 2 nm thick film possesses a polarization of bulk value. The giant enhancement of polarization is proposed to result from the charge transfer at interfaces.
      PubDate: 2017-10-25T02:11:51.490954-05:
      DOI: 10.1002/adma.201703543
       
  • Atomically Thin Femtojoule Memristive Device
    • Authors: Huan Zhao; Zhipeng Dong, He Tian, Don DiMarzi, Myung-Geun Han, Lihua Zhang, Xiaodong Yan, Fanxin Liu, Lang Shen, Shu-Jen Han, Steve Cronin, Wei Wu, Jesse Tice, Jing Guo, Han Wang
      Abstract: The morphology and dimension of the conductive filament formed in a memristive device are strongly influenced by the thickness of its switching medium layer. Aggressive scaling of this active layer thickness is critical toward reducing the operating current, voltage, and energy consumption in filamentary-type memristors. Previously, the thickness of this filament layer has been limited to above a few nanometers due to processing constraints, making it challenging to further suppress the on-state current and the switching voltage. Here, the formation of conductive filaments in a material medium with sub-nanometer thickness formed through the oxidation of atomically thin two-dimensional boron nitride is studied. The resulting memristive device exhibits sub-nanometer filamentary switching with sub-pA operation current and femtojoule per bit energy consumption. Furthermore, by confining the filament to the atomic scale, current switching characteristics are observed that are distinct from that in thicker medium due to the profoundly different atomic kinetics. The filament morphology in such an aggressively scaled memristive device is also theoretically explored. These ultralow energy devices are promising for realizing femtojoule and sub-femtojoule electronic computation, which can be attractive for applications in a wide range of electronics systems that desire ultralow power operation.A nonvolatile memristive device with a sub-nm thick switching layer, sub-pA operating current, and femtojoule per bit energy consumption is demonstrated. The ultrathin medium layer is formed through the oxidation of atomically thin hexagonal boron nitride. Due to the atomic-scale confinement of the filament length, current switching characteristics disparate from that in thicker medium are observed resulting from the distinct ionic kinetics.
      PubDate: 2017-10-25T02:11:03.37333-05:0
      DOI: 10.1002/adma.201703232
       
  • Magnetic Susceptibility Study of Sub-Pico-emu Sample Using a
           Micromagnetometer: An Investigation through Bistable Spin-Crossover
           Materials
    • Authors: Souleymane Kamara; Quang-Hung Tran, Vincent Davesne, Gautier Félix, Lionel Salmon, Kunwoo Kim, CheolGi Kim, Azzedine Bousseksou, Ferial Terki
      Abstract: A promising and original method to study the spin-transition in bistable spin-crossover (SCO) materials using a magnetoresistive multiring sensor and its self-generated magnetic field is reported. Qualitative and quantitative studies are carried out combining theoretical and experimental approaches. The results show that only a small part of matter dropped on the sensor surface is probed by the device. At a low bias-current range, the number of detected nanoparticles depends on the amplitude of the current. However, in agreement with the theoretical model, the stray voltage from the particles is proportional to the current squared. By changing both the bias current and the concentration of particle droplet, the thermal hysteresis of an ultrasmall volume, 1 × 10−4 mm3, of SCO particles is measured. The local probe of the experimental setup allows a highest resolution of 4 × 10−14 emu to be reached, which is never achieved by experimental methods at room temperature.An original and ultrasensitive method based on the self-generated magnetic field of the magneto-resistive (MR) multi-ring sensor is developed to study the spin-switching in bistable spin-crossover materials. The spin transition of the lowest volume of SCO nanoparticles of 1 × 10–4 mm3 is detected. The device allows a resolution of 4 × 10–14 emu to be achieved at room temperature.
      PubDate: 2017-10-25T02:10:32.794026-05:
      DOI: 10.1002/adma.201703073
       
  • Inkjet-Printed Nanocavities on a Photonic Crystal Template
    • Authors: Frederic S. F. Brossard; Vincenzo Pecunia, Andrew J. Ramsay, Jonathan P. Griffiths, Maxime Hugues, Henning Sirringhaus
      Abstract: The last decade has witnessed the rapid development of inkjet printing as an attractive bottom-up microfabrication technology due to its simplicity and potentially low cost. The wealth of printable materials has been key to its widespread adoption in organic optoelectronics and biotechnology. However, its implementation in nanophotonics has so far been limited by the coarse resolution of conventional inkjet-printing methods. In addition, the low refractive index of organic materials prevents the use of “soft-photonics” in applications where strong light confinement is required. This study introduces a hybrid approach for creating and fine tuning high-Q nanocavities, involving the local deposition of an organic ink on the surface of an inorganic 2D photonic crystal template using a commercially available high-resolution inkjet printer. The controllability of this approach is demonstrated by tuning the resonance of the printed nanocavities by the number of printer passes and by the fabrication of photonic crystal molecules with controllable splitting. The versatility of this method is evidenced by the realization of nanocavities obtained by surface deposition on a blank photonic crystal. A new method for a free-form, high-density, material-independent, and high-throughput fabrication technique is thus established with a manifold of opportunities in photonic applications.Reproducible and structurally tunable high-Q cavities with small modal volumes are fabricated by a new method via femtoliter inkjet printing on a photonic crystal template. The versatility of the method enables the realization of nanocavities through surface deposition on a defect-free photonic crystal. This thus establishes a free-form, high-density, material-independent, and high-throughput fabrication technique, with manifold opportunities in photonic applications.
      PubDate: 2017-10-24T11:51:05.193705-05:
      DOI: 10.1002/adma.201704425
       
  • Microporous Organic Materials for Membrane-Based Gas Separation
    • Authors: Xiaoqin Zou; Guangshan Zhu
      Abstract: Membrane materials with excellent selectivity and high permeability are crucial to efficient membrane gas separation. Microporous organic materials have evolved as an alternative candidate for fabricating membranes due to their inherent attributes, such as permanent porosity, high surface area, and good processability. Herein, a unique pore-chemistry concept for the designed synthesis of microporous organic membranes, with an emphasis on the relationship between pore structures and membrane performances, is introduced. The latest advances in microporous organic materials for potential membrane application in gas separation of H2, CO2, O2, and other industrially relevant gases are summarized. Representative examples of the recent progress in highly selective and permeable membranes are highlighted with some fundamental analyses from pore characteristics, followed by a brief perspective on future research directions.Recent advances regarding microporous organic materials for membrane gas separation are reviewed. Critical challenges associated with the designed synthesis of membrane materials with defined porous structures, and the correlations between pore chemistry and membrane separation performance, in terms of selectivity and permeability, are discussed.
      PubDate: 2017-10-24T06:28:25.6607-05:00
      DOI: 10.1002/adma.201700750
       
  • Nanoscale Bubble Domains and Topological Transitions in Ultrathin
           Ferroelectric Films
    • Authors: Qi Zhang; Lin Xie, Guangqing Liu, Sergei Prokhorenko, Yousra Nahas, Xiaoqing Pan, Laurent Bellaiche, Alexei Gruverman, Nagarajan Valanoor
      Abstract: Observation of a new type of nanoscale ferroelectric domains, termed as “bubble domains”—laterally confined spheroids of sub-10 nm size with local dipoles self-aligned in a direction opposite to the macroscopic polarization of a surrounding ferroelectric matrix—is reported. The bubble domains appear in ultrathin epitaxial PbZr0.2Ti0.8O3/SrTiO3/PbZr0.2Ti0.8O3 ferroelectric sandwich structures due to the interplay between charge and lattice degrees of freedom. The existence of the bubble domains is revealed by high-resolution piezoresponse force microscopy (PFM), and is corroborated by aberration-corrected atomic-resolution scanning transmission electron microscopy mapping of the polarization displacements. An incommensurate phase and symmetry breaking is found within these domains resulting in local polarization rotation and hence impart a mixed Néel–Bloch-like character to the bubble domain walls. PFM hysteresis loops for the bubble domains reveal that they undergo an irreversible phase transition to cylindrical domains under the electric field, accompanied by a transient rise in the electromechanical response. The observations are in agreement with ab-initio-based calculations, which reveal a very narrow window of electrical and elastic parameters that allow the existence of bubble domains. The findings highlight the richness of polar topologies possible in ultrathin ferroelectric structures and bring forward the prospect of emergent functionalities due to topological transitions.Nanoscale spheroid domains—“bubble domains”—sub-10 nm in lateral size with local dipoles self-aligned in a direction opposite to the polarization of the surrounding ferroelectric matrix are reported in ultrathin epitaxial ferroelectric heterostructures. Incommensurate dipolar order and symmetry breaking is found within these domains, which leads to local polarization rotation and consequently mixed Néel–Bloch-like character to the bubble domain walls.
      PubDate: 2017-10-24T06:18:10.732852-05:
      DOI: 10.1002/adma.201702375
       
  • Toward a New Generation of Smart Biomimetic Actuators for Architecture
    • Authors: Simon Poppinga; Cordt Zollfrank, Oswald Prucker, Jürgen Rühe, Achim Menges, Tiffany Cheng, Thomas Speck
      Abstract: Motile plant structures (e.g., leaves, petals, cone scales, and capsules) are functionally highly robust and resilient concept generators for the development of biomimetic actuators for architecture. Here, a concise review of the state-of-the-art of plant movement principles and derived biomimetic devices is provided. Achieving complex and higher-dimensional shape changes and passive-hydraulic actuation at a considerable time scale, as well as mechanical robustness of the motile technical structures, is challenging. For example, almost all currently available bioinspired hydraulic actuators show similar limitations due to the poroelastic time scale. Therefore, a major challenge is increasing the system size to the meter range, with actuation times of minutes or below. This means that response speed and flow rate need significant improvement for the systems, and the long-term performance degradation issue of hygroscopic materials needs to be addressed. A theoretical concept for “escaping” the poroelastic regime is proposed, and the possibilities for enhancing the mechanical properties of passive-hydraulic bilayer actuators are discussed. Furthermore, the promising aspects for further studies to implement tropistic movement behavior are presented, i.e., movement that depends on the direction of the triggering stimulus, which can finally lead to “smart building skins” that autonomously and self-sufficiently react to changing environmental stimuli in a direction-dependent manner.State-of-the-art biomimetic hydraulic actuators have two major disadvantages: low mechanical robustness and actuation-speed impediment by the poroelastic timescale. A concise summary of how plant motions can inspire technical kinetic devices is presented, and solutions for the problems mentioned are discussed.
      PubDate: 2017-10-24T06:16:22.643383-05:
      DOI: 10.1002/adma.201703653
       
  • Large-Scale, Long-Range-Ordered Patterning of Nanocrystals via
           Capillary-Bridge Manipulation
    • Authors: Jiangang Feng; Qian Song, Bo Zhang, Yuchen Wu, Tie Wang, Lei Jiang
      Abstract: Deterministic assembly of nanoparticles with programmable patterns is a core opportunity for property-by-design fabrication and large-scale integration of functional materials and devices. The wet-chemical-synthesized colloidal nanocrystals are compatible with solution assembly techniques, thus possessing advantages of high efficiency, low cost, and large scale. However, conventional solution process suffers from tradeoffs between spatial precision and long-range order of nanocrystal assembly arising from the uncontrollable dewetting dynamics and fluid flow. Here, a capillary-bridge manipulation method is demonstrated for directing the dewetting of nanocrystal inks and deterministically patterning long-range-ordered superlattice structures. This is achieved by employing micropillars with programmable size, arrangement, and shape, which permits deterministic manipulation of geometry, position, and dewetting dynamics of capillary bridges. Various superlattice structures, including one-dimensional (1D), circle, square, pentagon, hexagon, pentagram, cross arrays, are fabricated. Compared to the glassy thin films, long-range-ordered superlattice arrays exhibit improved ferroelectric polarization. Coassembly of nanocrystal superlattice and organic functional molecule is further demonstrated. Through introducing azobenzene into superlattice arrays, a switchable ferroelectric polarization is realized, which is triggered by order–disorder transition of nanocrystal stacking in reversible isomerization process of azobenzene. This method offers a platform for patterning nanocrystal superlattices and fabricating microdevices with functionalities for multiferroics, electronics, and photonics.Deterministic patterning of nanocrystal superlattices with regulated geometry, size, position, and long-range order is demonstrated by controlling dewetting dynamics in discrete capillary bridges. 1D, polygon, and circle structures of nanocrystal superlattices are fabricated. The long-range-ordered superlattice arrays present improved ferroelectric performance, and responsive polarization can be realized by integrating azobenzene molecules into nanocrystal superlattices.
      PubDate: 2017-10-23T11:46:01.367894-05:
      DOI: 10.1002/adma.201703143
       
  • Bioinspired Nanocomposite Hydrogels with Highly Ordered Structures
    • Authors: Ziguang Zhao; Ruochen Fang, Qinfeng Rong, Mingjie Liu
      Abstract: In the human body, many soft tissues with hierarchically ordered composite structures, such as cartilage, skeletal muscle, the corneas, and blood vessels, exhibit highly anisotropic mechanical strength and functionality to adapt to complex environments. In artificial soft materials, hydrogels are analogous to these biological soft tissues due to their “soft and wet” properties, their biocompatibility, and their elastic performance. However, conventional hydrogel materials with unordered homogeneous structures inevitably lack high mechanical properties and anisotropic functional performances; thus, their further application is limited. Inspired by biological soft tissues with well-ordered structures, researchers have increasingly investigated highly ordered nanocomposite hydrogels as functional biological engineering soft materials with unique mechanical, optical, and biological properties. These hydrogels incorporate long-range ordered nanocomposite structures within hydrogel network matrixes. Here, the critical design criteria and the state-of-the-art fabrication strategies of nanocomposite hydrogels with highly ordered structures are systemically reviewed. Then, recent progress in applications in the fields of soft actuators, tissue engineering, and sensors is highlighted. The future development and prospective application of highly ordered nanocomposite hydrogels are also discussed.Biological soft tissues provide an inspiration for the fabrication of nanocomposite hydrogels with highly ordered structures by using various strategies, including magnetic fields, electric fields, mechanical strain, freeze-casting, and self-assembly. Based on such ordered nanocomposite structures, these hydrogels exhibit highly anisotropic properties and unique functionalities. Therefore, highly ordered nanocomposite hydrogels can serve as significant and promising soft materials for a variety of applications.
      PubDate: 2017-10-23T11:41:40.98074-05:0
      DOI: 10.1002/adma.201703045
       
  • Structure Formation in Soft-Matter Solutions Induced by Solvent
           Evaporation
    • Authors: Jiajia Zhou; Xingkun Man, Ying Jiang, Masao Doi
      Abstract: Solvent evaporation in soft-matter solutions (solutions of colloidal particles, polymers, and their mixtures) is an important process in material making and in the printing and coating industries. The solvent-evaporation process determines the structure of materials and strongly affects their performance. Solvent evaporation involves many physicochemical processes: flow, diffusion, crystallization, gelation, glass transition, etc. and is quite complex. Here, recent progress in this important process is reported, with a special focus on theoretical and simulation studies.Understanding the solvent-evaporation process, especially how to control the structural changes during evaporation, is an important subject in many applications. Solutes are kinetically mobile in solution; therefore, the dynamics are fast and the fabrication time can be reduced. The final structure can be controlled by external means such as evaporation rate and solution pH value.
      PubDate: 2017-10-23T07:36:47.211256-05:
      DOI: 10.1002/adma.201703769
       
  • Antiadhesion Organogel Materials: From Liquid to Solid
    • Authors: Jianyong Lv; Xi Yao, Yongmei Zheng, Jianjun Wang, Lei Jiang
      Abstract: Various organogel materials with either a liquid or solid surface layer have recently been designed and prepared. These surface materials can substantially reduce the adhesion of foreign deposits such as water, blood, paint, ice, and so on; therefore, they exhibit great potential for the easy removal of foreign deposits. Here, a brief discussion about the mechanism of organogel materials in reducing adhesion is given; then, examples of liquid organogels for fighting against varieties of complex fluidic deposits are presented, and efforts in preventing the depletion of liquid are discussed. Finally, applications of antiadhesion organogels with multifunctionality, and the strategy of replacing liquids with solids are presented.Recent advances in designing and investigating antiadhesion organogel materials are summarized. Easy removal of almost all unwanted deposits is achieved with the help of liquid or solid surface layers. Due to the diversity of gelators and the designability of the organogels, multifunctionality, high performance, and excellent durability of antiadhesion materials can be anticipated.
      PubDate: 2017-10-23T07:36:03.186058-05:
      DOI: 10.1002/adma.201703032
       
  • A Supramolecular Nanocomposite as a Near-Infrared-Transmitting Optical
           Filter for Security and Forensic Applications
    • Authors: Samrat Ghosh; Sandeep Cherumukkil, Cherumuttathu H. Suresh, Ayyappanpillai Ajayaghosh
      Abstract: Visibly opaque but near-infrared (NIR)-transparent materials are an essential component for night-vision photography, security imaging, and forensic applications. Herein, the development of a novel supramolecular black dye from a diketopyrrolopyrrole (DPP)-based low-molecular-weight organogelator is described. In the solution state, the monomer of DPP–Amide exhibits a deep green color with a broad absorption in the visible region due to firm intramolecular charge transfer from the donor to the acceptor unit. Interestingly, due to the synergistic effect of H-bonding and π-stacking, DPP–Amide can form a black organogel in toluene with complete spectral coverage from 300 to 800 nm, and transmits beyond 850 nm. In the gel state, complete visible-spectrum coverage is achieved due to the simultaneous formation of both H- and J-type aggregates, which is confirmed via absorption studies. To create a free-standing NIR-transmitting elastomeric black filter, nanoscopic molecular aggregates of DPP–Amide (0.15 wt%) are embedded into a poly(dimethylsiloxane) matrix. This nanocomposite possesses high NIR transparency with good thermal and photostability for practical applications. Finally, the use of the developed material for NIR photography, security, and forensic-related applications is demonstrated.A π-conjugated diketopyrrolopyrrole (DPP–Amide) forms a black supramolecular organogel with a broad spectral absorption from 300 to 800 nm, and transmits beyond 850 nm. A free-standing near-infrared-filter lens fabricated by incorporating the nanoscopic molecular aggregates of DPP–Amide into a poly(dimethylsiloxane) (PDMS) matrix is found to be useful for NIR photography, security, and forensic-related applications.
      PubDate: 2017-10-23T07:32:55.64634-05:0
      DOI: 10.1002/adma.201703783
       
  • Photovoltaic–Pyroelectric Coupled Effect Induced Electricity for
           Self-Powered Photodetector System
    • Authors: Nan Ma; Kewei Zhang, Ya Yang
      Abstract: Ferroelectric materials have demonstrated novel photovoltaic effect to scavenge solar energy. However, most of the ferroelectric materials with wide bandgaps (2.7–4 eV) suffer from low power conversion efficiency of less than 0.5% due to absorbing only 8–20% of solar spectrum. Instead of harvesting solar energy, these ferroelectric materials can be well suited for photodetector applications, especially for sensing near-UV irradiations. Here, a ferroelectric BaTiO3 film-based photodetector is demonstrated that can be operated without using any external power source and a fast sensing of 405 nm light illumination is enabled. As compared with photovoltaic effect, both the responsivity and the specific detectivity of the photodetector can be dramatically enhanced by larger than 260% due to the light-induced photovoltaic–pyroelectric coupled effect. A self-powered photodetector array system can be utilized to achieve spatially resolved light intensity detection by recording the output voltage signals as a mapping figure.The photovoltaic–pyroelectric coupled effect is utilized to enhance the sensing performance of self-powered ITO/BaTiO3/Ag photodetector for realizing fast 405 nm light detection. A self-powered photodetector array system can be utilized to achieve spatially resolved light intensity detection by recording the output voltage signals as a mapping figure.
      PubDate: 2017-10-23T07:31:37.360957-05:
      DOI: 10.1002/adma.201703694
       
  • Guided Molecular Assembly on a Locally Reactive 2D Material
    • Authors: Ben Warner; Tobias G. Gill, Vasile Caciuc, Nicolae Atodiresei, Antoine Fleurence, Yasuo Yoshida, Yukio Hasegawa, Stefan Blügel, Yukiko Yamada-Takamura, Cyrus F. Hirjibehedin
      Abstract: Atomically precise engineering of the position of molecular adsorbates on surfaces of 2D materials is key to their development in applications ranging from catalysis to single-molecule spintronics. Here, stable room-temperature templating of individual molecules with localized electronic states on the surface of a locally reactive 2D material, silicene grown on ZrB2, is demonstrated. Using a combination of scanning tunneling microscopy and density functional theory, it is shown that the binding of iron phthalocyanine (FePc) molecules is mediated via the strong chemisorption of the central Fe atom to the sp3-like dangling bond of Si atoms in the linear silicene domain boundaries. Since the planar Pc ligand couples to the Fe atom mostly through the in-plane d orbitals, localized electronic states resembling those of the free molecule can be resolved. Furthermore, rotation of the molecule is restrained because of charge rearrangement induced by the bonding. These results highlight how nanoscale changes can induce reactivity in 2D materials, which can provide unique surface interactions for enabling novel forms of guided molecular assembly.Molecular templating using a locally reactive 2D material is achieved at the domain boundaries of silicene formed on ZrB2. Selective bonding between silicene sp3-like states and the dz2 orbitals of iron phthalocyanine (FePc) molecules preserves electronic states that are strongly localized on the Pc ligand while pinning the molecule into a unique rotational alignment up to room temperature.
      PubDate: 2017-10-11T06:58:14.514828-05:
      DOI: 10.1002/adma.201703929
       
  • Imbedded Nanocrystals of CsPbBr3 in Cs4PbBr6: Kinetics, Enhanced
           Oscillator Strength, and Application in Light-Emitting Diodes
    • Authors: Junwei Xu; Wenxiao Huang, Peiyun Li, Drew R. Onken, Chaochao Dun, Yang Guo, Kamil B. Ucer, Chang Lu, Hongzhi Wang, Scott M. Geyer, Richard T. Williams, David L. Carroll
      Abstract: Solution-grown films of CsPbBr3 nanocrystals imbedded in Cs4PbBr6 are incorporated as the recombination layer in light-emitting diode (LED) structures. The kinetics at high carrier density of pure (extended) CsPbBr3 and the nanoinclusion composite are measured and analyzed, indicating second-order kinetics in extended and mainly first-order kinetics in the confined CsPbBr3, respectively. Analysis of absorption strength of this all-perovskite, all-inorganic imbedded nanocrystal composite relative to pure CsPbBr3 indicates enhanced oscillator strength consistent with earlier published attribution of the sub-nanosecond exciton radiative lifetime in nanoprecipitates of CsPbBr3 in melt-grown CsBr host crystals and CsPbBr3 evaporated films.Photoluminescence and electroluminescence in solution-grown films of CsPbBr3 nanocrystals imbedded in Cs4PbBr6 are studied. Radiative recombination kinetics are second order in bulk CsPbBr3 and first order in CsPbBr3 nanoinclusions. Exciton absorption strength and sub-nanosecond lifetime imply enhanced oscillator strength in the confined form. A semiconductor that is dark in bulk lights up as a highly efficient and fast nanocomposite light emitter.
      PubDate: 2017-10-10T07:32:20.186123-05:
      DOI: 10.1002/adma.201703703
       
  • Stimulated Transitions of Directed Nonequilibrium Self-Assemblies
    • Authors: Alexander A. Steinschulte; Andrea Scotti, Khosrow Rahimi, Oleksii Nevskyi, Alex Oppermann, Sabine Schneider, Steffen Bochenek, Marie F. Schulte, Karen Geisel, Felicitas Jansen, Andre Jung, Sabrina Mallmann, Roland Winter, Walter Richtering, Dominik Wöll, Ralf Schweins, Nicholas J. Warren, Felix A. Plamper
      Abstract: Near-equilibrium stimulus-responsive polymers have been used extensively to introduce morphological variations in dependence of adaptable conditions. Far-less-well studied are triggered transformations at constant conditions. These require the involvement of metastable states, which are either able to approach the equilibrium state after deviation from metastability or can be frozen on returning from nonequilibrium to equilibrium. Such functional nonequilibrium macromolecular systems hold great promise for on-demand transformations, which result in substantial changes in their material properties, as seen for triggered gelations. Herein, a diblock copolymer system consisting of a hydrophilic block and a block that is responsive to both pressure and temperature, is introduced. This species demonstrates various micellar transformations upon leaving equilibrium/nonequilibrium states, which are triggered by a temperature deflection or a temporary application of hydrostatic pressure.Temporary pressure or temperature deflections induce property and morphology changes of easily prepared and kinetically stable nonequilibrium micelles. These systems allow a stimulated physical gelation at constant conditions before and after trigger application. As an extraordinary example, a specific polymer, which can show all principle micellar morphologies at the same concentration c, pressure p, and temperature T, is highlighted.
      PubDate: 2017-10-10T07:31:50.194171-05:
      DOI: 10.1002/adma.201703495
       
  • A Fluid Liquid-Crystal Material with Highly Polar Order
    • Authors: Hiroya Nishikawa; Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago, Hirotsugu Kikuchi
      Abstract: An anomalously large dielectric permittivity of ≈104 is found in the mesophase temperature range (MP phase) wherein high fluidity is observed for a liquid-crystal compound having a 1,3-dioxane unit in the mesogenic core (DIO). In this temperature range, no sharp X-ray diffraction peak is observed at both small and wide Bragg angles, similar to that for a nematic phase; however, an inhomogeneous sandy texture or broken Schlieren one is observed via polarizing optical microscopy, unlike that for a conventional nematic phase. DIO exhibits polarization switching with a large polarization value, i.e., P = 4.4 µC cm−2, and a parallelogram-shaped polarization–electric field hysteresis loop in the MP phase. The inhomogeneously aligned DIO in the absence of an electric field adopts a uniform orientation along an applied electric field when field-induced polarization switching occurs. Furthermore, sufficiently larger second-harmonic generation is observed for DIO in the MP phase. Second-harmonic-generation interferometry clearly shows that the sense of polarization is inverted when the +/− sign of the applied electric field in MP is reversed. These results suggest that a unidirectional, ferroelectric-like parallel polar arrangement of the molecules is generated along the director in the MP phase.An anomalously large dielectric permittivity of ≈104 is found for a liquid-crystal compound having a 1,3-dioxane unit (DIO) in the high-fluid mesophase temperature range. In addition, DIO shows ferroelectric-like polarization of 4.4 µC cm−2, which is several hundred times larger than those of conventional ferroelectric chiral smectic C materials, and second-harmonic-generation activity.
      PubDate: 2017-10-10T07:30:44.098684-05:
      DOI: 10.1002/adma.201702354
       
  • Slow-Photon-Effect-Induced Photoelectrical-Conversion Efficiency
           Enhancement for Carbon-Quantum-Dot-Sensitized Inorganic CsPbBr3 Inverse
           Opal Perovskite Solar Cells
    • Authors: Shujie Zhou; Rui Tang, Longwei Yin
      Abstract: All-inorganic cesium lead halide perovskite is suggested as a promising candidate for perovskite solar cells due to its prominent thermal stability and comparable light absorption ability. Designing textured perovskite films rather than using planar-architectural perovskites can indeed optimize the optical and photoelectrical conversion performance of perovskite photovoltaics. Herein, for the first time, this study demonstrates a rational strategy for fabricating carbon quantum dot (CQD-) sensitized all-inorganic CsPbBr3 perovskite inverse opal (IO) films via a template-assisted, spin-coating method. CsPbBr3 IO introduces slow-photon effect from tunable photonic band gaps, displaying novel optical response property visible to naked eyes, while CQD inlaid among the IO frameworks not only broadens the light absorption range but also improves the charge transfer process. Applied in the perovskite solar cells, compared with planar CsPbBr3, slow-photon effect of CsPbBr3 IO greatly enhances the light utilization, while CQD effectively facilitates the electron–hole extraction and injection process, prolongs the carrier lifetime, jointly contributing to a double-boosted power conversion efficiency (PCE) of 8.29% and an increased incident photon-to-electron conversion efficiency of up to 76.9%. The present strategy on CsPbBr3 IO to enhance perovskite PCE can be extended to rationally design other novel optoelectronic devices.Novel carbon quantum dot (CQD)-sensitized inorganic CsPbBr3 inverse opal perovskite solar cells are fabricated for the first time. CsPbBr3 inverse opal induces improved light utilization originating from the slow-photon effect with tunable photonic band gaps, while CQD helps to facilitate the charge transfer process, which jointly contributes to a greatly improved photoelectrical conversion efficiency with outstanding stability.
      PubDate: 2017-10-10T04:46:37.962822-05:
      DOI: 10.1002/adma.201703682
       
  • Magnetically Controlled Growth-Factor-Immobilized Multilayer Cell Sheets
           for Complex Tissue Regeneration
    • Authors: Wenjie Zhang; Guangzheng Yang, Xiansong Wang, Liting Jiang, Fei Jiang, Guanglong Li, Zhiyuan Zhang, Xinquan Jiang
      Abstract: The scaffold-free cell-sheet technique plays a significant role in stem-cell-based regeneration. Furthermore, growth factors are known to direct stem cell differentiation and enhance tissue regeneration. However, the absence of an effective means to incorporate growth factors into the cell sheets hinders further optimization of the regeneration efficiency. Here, a novel design of magnetically controlled “growth-factor-immobilized cell sheets” is reported. A new Fe3O4 magnetic nanoparticle (MNP) coated with nanoscale graphene oxide (nGO@Fe3O4) is developed to label stem cells and deliver growth factors. First, the nGO@Fe3O4 MNPs can be easily swallowed by dental-pulp stem cells (DPSCs) and have no influence on cell viability. Thus, the MNP-labeled cells can be organized via magnetic force to form multilayered cell sheets in different patterns. Second, compared to traditional Fe3O4 nanoparticles, the graphene oxide coating provides plenty of carboxyl groups to bind and deliver growth factors. Therefore, with these nGO@Fe3O4 MNPs, bone-morphogenetic-protein-2 (BMP2) is successfully incorporated into the DPSCs sheets to induce more bone formation. Furthermore, an integrated osteochondral complex is also constructed using a combination of DPSCs/TGFβ3 and DPSCs/BMP2. All these results demonstrate that the new cell-sheet tissue-engineering approach exhibits promising potential for future use in regenerative medicine.A novel design for “growth-factor-immobilized cell sheets” formed under the control of magnetic force is introduced to optimize regeneration efficiency, based on a new nanoscale graphene-oxide-coated Fe3O4 magnetic nanoparticle. The nanocomposites provide a novel magnetically controlled vehicle for delivery of both stem cells and growth factors, and they exhibit promising potential for future use in regenerative medicine.
      PubDate: 2017-10-09T07:34:02.830994-05:
      DOI: 10.1002/adma.201703795
       
  • High-Performance Flexible Photodetectors based on High-Quality Perovskite
           Thin Films by a Vapor–Solution Method
    • Authors: Wei Hu; Wei Huang, Shuzhen Yang, Xiao Wang, Zhenyu Jiang, Xiaoli Zhu, Hong Zhou, Hongjun Liu, Qinglin Zhang, Xiujuan Zhuang, Junliang Yang, Dong Ha Kim, Anlian Pan
      Abstract: Organometal halide perovskites are new light-harvesting materials for lightweight and flexible optoelectronic devices due to their excellent optoelectronic properties and low-temperature process capability. However, the preparation of high-quality perovskite films on flexible substrates has still been a great challenge to date. Here, a novel vapor–solution method is developed to achieve uniform and pinhole-free organometal halide perovskite films on flexible indium tin oxide/poly(ethylene terephthalate) substrates. Based on the as-prepared high-quality perovskite thin films, high-performance flexible photodetectors (PDs) are constructed, which display a nR value of 81 A W−1 at a low working voltage of 1 V, three orders higher than that of previously reported flexible perovskite thin-film PDs. In addition, these flexible PDs exhibit excellent flexural stability and durability under various bending situations with their optoelectronic performance well retained. This breakthrough on the growth of high-quality perovskite thin films opens up a new avenue to develop high-performance flexible optoelectronic devices.A novel vapor–solution method is developed to achieve uniform and pinhole-free organometal halide perovskite films on flexible indium tin oxide/poly(ethylene terephthalate) substrates. Based on the as-prepared high-quality perovskite thin films, high-performance flexible photodetectors are constructed with a very high R value, excellent flexural stability, and durability under various bending situations.
      PubDate: 2017-10-09T07:31:58.666229-05:
      DOI: 10.1002/adma.201703256
       
  • Rational In Silico Design of an Organic Semiconductor with Improved
           Electron Mobility
    • Authors: Pascal Friederich; Verónica Gómez, Christian Sprau, Velimir Meded, Timo Strunk, Michael Jenne, Andrea Magri, Franz Symalla, Alexander Colsmann, Mario Ruben, Wolfgang Wenzel
      Abstract: Organic semiconductors find a wide range of applications, such as in organic light emitting diodes, organic solar cells, and organic field effect transistors. One of their most striking disadvantages in comparison to crystalline inorganic semiconductors is their low charge-carrier mobility, which manifests itself in major device constraints such as limited photoactive layer thicknesses. Trial-and-error attempts to increase charge-carrier mobility are impeded by the complex interplay of the molecular and electronic structure of the material with its morphology. Here, the viability of a multiscale simulation approach to rationally design materials with improved electron mobility is demonstrated. Starting from one of the most widely used electron conducting materials (Alq3), novel organic semiconductors with tailored electronic properties are designed for which an improvement of the electron mobility by three orders of magnitude is predicted and experimentally confirmed.The viability of a multiscale simulation approach to rationally design organic semiconductors with improved electron mobility is demonstrated. Novel materials with tailored electronic properties are designed for which an improvement of the electron mobility by three orders of magnitude is predicted and experimentally confirmed.
      PubDate: 2017-10-09T07:31:14.229362-05:
      DOI: 10.1002/adma.201703505
       
  • Wrinkled 2D Materials: A Versatile Platform for Low-Threshold Stretchable
           Random Lasers
    • Authors: Han-Wen Hu; Golam Haider, Yu-Ming Liao, Pradip Kumar Roy, Rini Ravindranath, Huan-Tsung Chang, Cheng-Hsin Lu, Chang-Yang Tseng, Tai-Yung Lin, Wei-Heng Shih, Yang-Fang Chen
      Abstract: A stretchable, flexible, and bendable random laser system capable of lasing in a wide range of spectrum will have many potential applications in next- generation technologies, such as visible-spectrum communication, superbright solid-state lighting, biomedical studies, fluorescence, etc. However, producing an appropriate cavity for such a wide spectral range remains a challenge owing to the rigidity of the resonator for the generation of coherent loops. 2D materials with wrinkled structures exhibit superior advantages of high stretchability and a suitable matrix for photon trapping in between the hill and valley geometries compared to their flat counterparts. Here, the intriguing functionalities of wrinkled reduced graphene oxide, single-layer graphene, and few-layer hexagonal boron nitride, respectively, are utilized to design highly stretchable and wearable random laser devices with ultralow threshold. Using methyl-ammonium lead bromide perovskite nanocrystals (PNC) to illustrate the working principle, the lasing threshold is found to be ≈10 µJ cm−2, about two times less than the lowest value ever reported. In addition to PNC, it is demonstrated that the output lasing wavelength can be tuned using different active materials such as semiconductor quantum dots. Thus, this study is very useful for the future development of high-performance wearable optoelectronic devices.2D materials with wrinkled structures exhibit superior advantages of high stretchability, along with a suitable matrix for photon trapping in between the hill and valley geometries compared to their flat counterparts. This is the first attempt to integrate wrinkled 2D materials with a random laser system, which enables highly stretchable and wearable random laser devices with ultralow threshold to be designed.
      PubDate: 2017-10-09T07:30:53.606543-05:
      DOI: 10.1002/adma.201703549
       
  • Enhanced Open-Circuit Voltage in Colloidal Quantum Dot Photovoltaics via
           Reactivity-Controlled Solution-Phase Ligand Exchange
    • Authors: Jea Woong Jo; Younghoon Kim, Jongmin Choi, F. Pelayo García Arquer, Grant Walters, Bin Sun, Olivier Ouellette, Junghwan Kim, Andrew H. Proppe, Rafael Quintero-Bermudez, James Fan, Jixian Xu, Chih Shan Tan, Oleksandr Voznyy, Edward H. Sargent
      Abstract: The energy disorder that arises from colloidal quantum dot (CQD) polydispersity limits the open-circuit voltage (VOC) and efficiency of CQD photovoltaics. This energy broadening is significantly deteriorated today during CQD ligand exchange and film assembly. Here, a new solution-phase ligand exchange that, via judicious incorporation of reactivity-engineered additives, provides improved monodispersity in final CQD films is reported. It has been found that increasing the concentration of the less reactive species prevents CQD fusion and etching. As a result, CQD solar cells with a VOC of 0.7 V (vs 0.61 V for the control) for CQD films with exciton peak at 1.28 eV and a power conversion efficiency of 10.9% (vs 10.1% for the control) is achieved.A new solution-phase ligand exchange method for preventing colloidal quantum dots fusion and etching is developed via judicious incorporation of reactivity-engineered additives. This method provides improved monodispersity in final colloidal quantum dot films and thus leads to the significant enhancement of open-circuit voltages in colloidal quantum dot solar cells.
      PubDate: 2017-10-09T07:30:28.78476-05:0
      DOI: 10.1002/adma.201703627
       
  • In Situ GIWAXS Analysis of Solvent and Additive Effects on PTB7 Thin Film
           Microstructure Evolution during Spin Coating
    • Authors: Eric F. Manley; Joseph Strzalka, Thomas J. Fauvell, Nicholas E. Jackson, Matthew J. Leonardi, Nicholas D. Eastham, Tobin J. Marks, Lin X. Chen
      Abstract: The influence of solvent and processing additives on the pathways and rates of crystalline morphology formation for spin-coated semiconducting PTB7 (poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)-carbonyl]-thieno[3,4-b]thiophenediyl]]) thin films is investigated by in situ grazing incidence wide-angle X-ray scattering (GIWAXS) and optical reflectance, to better understand polymer solar cell (PSC) optimization approaches. In situ characterization of PTB7 film formation from chloroform (CF), chlorobenzene (CB), and 1,2-dichlorobenzene (DCB) solutions, as well as CB solutions with 1% and 3% v/v of the processing additives 1-chloronapthalene (CN), diphenylether (DPE), and 1,8-diiodooctane (DIO), reveals multiple crystallization pathways with: (i) single-solvent systems exhibiting rapid (
      PubDate: 2017-10-09T00:33:34.317614-05:
      DOI: 10.1002/adma.201703933
       
  • Re Doping in 2D Transition Metal Dichalcogenides as a New Route to Tailor
           Structural Phases and Induced Magnetism
    • Authors: Vidya Kochat; Amey Apte, Jordan A. Hachtel, Hiroyuki Kumazoe, Aravind Krishnamoorthy, Sandhya Susarla, Juan Carlos Idrobo, Fuyuki Shimojo, Priya Vashishta, Rajiv Kalia, Aiichiro Nakano, Chandra Sekhar Tiwary, Pulickel M. Ajayan
      Abstract: Alloying in 2D results in the development of new, diverse, and versatile systems with prospects in bandgap engineering, catalysis, and energy storage. Tailoring structural phase transitions using alloying is a novel idea with implications in designing all 2D device architecture as the structural phases in 2D materials such as transition metal dichalcogenides are correlated with electronic phases. Here, this study develops a new growth strategy employing chemical vapor deposition to grow monolayer 2D alloys of Re-doped MoSe2 with show composition tunable structural phase variations. The compositions where the phase transition is observed agree well with the theoretical predictions for these 2D systems. It is also shown that in addition to the predicted new electronic phases, these systems also provide opportunities to study novel phenomena such as magnetism which broadens the range of their applications.Re doping is demonstrated to be a controllable way to tailor crystal structure and magnetic properties in chemical vapor deposition (CVD)-synthesized 2D transition metal dichalcogenides. Extra electrons from Re atoms induce a 2H–1T′ phase transformation in monolayer Mo1–xRexSe2 alloys. These results show that chemical doping is a promising pathway to tune structural and magnetic properties of other CVD-grown MX2 (M = Mo, W; X = S, Se).
      PubDate: 2017-10-09T00:30:21.873026-05:
      DOI: 10.1002/adma.201703754
       
  • Autonomous Ex Novo Chemical Assembly with Blebbing and Division of
           Functional Polymer Vesicles from a “Homogeneous Mixture”
    • Authors: Bishnu Prasad Bastakoti; Juan Perez-Mercader
      Abstract: The chemical energy and radicals from an oscillating chemical reaction are used to synthesize a polymer vesicle from a homogeneous solution of monomeric units. Periodically formed radicals from the Belousov–Zhabotinsky (B–Z) reaction initiate radical polymerization between a polyethylene glycol based chain transfer agent (PEG-CTA) and hydrophilic acrylonitrile monomers in water. The growth of a hydrophobic chain on the hydrophilic PEG chain induces self-assembly of polymeric amphiphiles to form micrometer-sized vesicles entrapping an active oscillating B–Z reaction. In our experimental conditions, the different chemical environments inside and outside the vesicles contribute to enlarge the area and diameter of the resulting self-assembled vesicles and, in some cases, promote blebbing and division.This study discusses the synthesis of amphiphilic block copolymers that self-assemble into micrometer-sized vesicles, while simultaneously entrapping the reaction that provides the radicals needed for the polymerization and shows their blebbing, a first step to system division, due to an internal reaction. The system does not use any biochemistry.
      PubDate: 2017-10-06T09:05:09.864522-05:
      DOI: 10.1002/adma.201704368
       
  • A Twisted Thieno[3,4-b]thiophene-Based Electron Acceptor Featuring a
           14-π-Electron Indenoindene Core for High-Performance Organic
           Photovoltaics
    • Authors: Sheng jie Xu; Zichun Zhou, Wuyue Liu, Zhongbo Zhang, Feng Liu, Hongping Yan, Xiaozhang Zhu
      Abstract: With an indenoindene core, a new thieno[3,4-b]thiophene-based small-molecule electron acceptor, 2,2′-((2Z,2′Z)-((6,6′-(5,5,10,10-tetrakis(2-ethylhexyl)-5,10-dihydroindeno[2,1-a]indene-2,7-diyl)bis(2-octylthieno[3,4-b]thiophene-6,4-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (NITI), is successfully designed and synthesized. Compared with 12-π-electron fluorene, a carbon-bridged biphenylene with an axial symmetry, indenoindene, a carbon-bridged E-stilbene with a centrosymmetry, shows elongated π-conjugation with 14 π-electrons and one more sp3 carbon bridge, which may increase the tunability of electronic structure and film morphology. Despite its twisted molecular framework, NITI shows a low optical bandgap of 1.49 eV in thin film and a high molar extinction coefficient of 1.90 × 105m−1 cm−1 in solution. By matching NITI with a large-bandgap polymer donor, an extraordinary power conversion efficiency of 12.74% is achieved, which is among the best performance so far reported for fullerene-free organic photovoltaics and is inspiring for the design of new electron acceptors.A thieno[3,4-b]thiophene-based electron acceptor, NITI, featuring a 14-π-electron indenoindene core is designed and synthesized. Despite its twisted molecular geometry, NITI shows a low optical bandgap and a high molar extinction coefficient. By matching NITI with a large-bandgap polymer donor, an extraordinary power conversion efficiency of 12.74% is achieved, which represents an exciting progress in the design of new electron acceptors.
      PubDate: 2017-10-06T09:04:45.64291-05:0
      DOI: 10.1002/adma.201704510
       
  • Lithiation Mechanism of Tunnel-Structured MnO2 Electrode Investigated by
           In Situ Transmission Electron Microscopy
    • Authors: Seung-Yong Lee; Lijun Wu, Altug S. Poyraz, Jianping Huang, Amy C. Marschilok, Kenneth J. Takeuchi, Esther S. Takeuchi, Miyoung Kim, Yimei Zhu
      Abstract: Manganese oxide (α-MnO2) has been considered a promising energy material, including as a lithium-based battery electrode candidate, due to its environmental friendliness. Thanks to its unique 1D [2 × 2] tunnel structure, α-MnO2 can be applied to a cathode by insertion reaction and to an anode by conversion reaction in corresponding voltage ranges, in a lithium-based battery. Numerous reports have attributed its remarkable performance to its unique tunnel structure; however, the precise electrochemical reaction mechanism remains unknown. In this study, finding of the lithiation mechanism of α-MnO2 nanowire by in situ transmission electron microscopy (TEM) is reported. By elaborately modifying the existing in situ TEM experimental technique, rapid lithium-ion diffusion through the tunnels is verified. Furthermore, by tracing the full lithiation procedure, the evolution of the MnO intermediate phase and the development of the MnO and Li2O phases with preferred orientations is demonstrated, which explains how the conversion reaction occurs in α-MnO2 material. This study provides a comprehensive understanding of the electrochemical lithiation process and mechanism of α-MnO2 material, in addition to the introduction of an improved in situ TEM biasing technique.Lithiation mechanism of tunnel-structured α-MnO2 electrode is elucidated by in situ transmission electron microscopy. The rapid lithium-ion diffusion through the tunnels is verified. Moreover, MnO intermediate phase evolution and the development of the MnO and Li2O phases with preferred orientations during the conversion reaction procedure are observed for the first time.
      PubDate: 2017-10-06T09:04:27.40653-05:0
      DOI: 10.1002/adma.201703186
       
  • Electrochemical Tantalum Oxide for Resistive Switching Memories
    • Authors: Andrea Zaffora; Deok-Yong Cho, Kug-Seung Lee, Francesco Di Quarto, Rainer Waser, Monica Santamaria, Ilia Valov
      Abstract: Redox-based resistive switching memories (ReRAMs) are strongest candidates for the next-generation nonvolatile memories fulfilling the criteria for fast, energy efficient, and scalable green IT. These types of devices can also be used for selector elements, alternative logic circuits and computing, and memristive and neuromorphic operations. ReRAMs are composed of metal/solid electrolyte/metal junctions in which the solid electrolyte is typically a metal oxide or multilayer oxides structures. Here, this study offers an effective and cheap electrochemical approach to fabricate Ta/Ta2O5-based devices by anodizing. This method allows to grow high-quality and dense oxide thin films onto a metallic substrates with precise control over morphology and thickness. Electrochemical-oxide-based devices demonstrate superior properties, i.e., endurance of at least 106 pulse cycles and/or 103I–V sweeps maintaining a good memory window with a low dispersion in ROFF and RON values, nanosecond fast switching, and data retention of at least 104 s. Multilevel programing capability is presented with both I–V sweeps and pulse measurements. Thus, it is shown that anodizing has a great prospective as a method for preparation of dense oxide films for resistive switching memories.Electrochemical oxides prepared by anodizing are a reliable and cheap approach for producing solid electrolytes for redox-based resistive switching memories (ReRAMs). Valence-changememories devices based on anodic Ta2O5 demonstrate high retention, endurance, switching times within nanoseconds, and low switching voltages. They have a high yield, extremely low variability, and offer defined multilevels. This approach is also valuable for 3D integration.
      PubDate: 2017-10-06T09:02:48.332606-05:
      DOI: 10.1002/adma.201703357
       
  • Thermoreversible Self-Assembly of Perfluorinated Core-Coronas
           Cellulose-Nanoparticles in Dry State
    • Authors: Yonggui Wang; Pedro B. Groszewicz, Sabine Rosenfeldt, Hendrik Schmidt, Cynthia A. Volkert, Philipp Vana, Torsten Gutmann, Gerd Buntkowsky, Kai Zhang
      Abstract: Self-assembly of nanoparticles (NPs) forming unique structures has been investigated extensively over the past few years. However, many self-assembled structures by NPs are irreversible, because they are generally constructed using their suspensions. It is still challenging for NPs to reversibly self-assemble in dry state, let alone of polymeric NPs with general sizes of hundreds of nm. Herein, this study reports a new reversible self-assembly phenomenon of NPs in dry state, forming thermoreversible strip-like supermolecular structures. These novel NPs of around 150 nm are perfluorinated surface-undecenoated cellulose nanoparticles (FSU-CNPs) with a core-coronas structure. The thermoreversible self-assembled structure is formed after drying in the air at the interface between FSU-CNP films and Teflon substrates. Remarkably, the formation and dissociation of this assembled structure are accompanied by a reversible conversion of the surface hydrophobicity, film transparency, and anisotropic properties. These findings show novel feasibility of reversible self-assembly of NPs in dry state, and thereby expand our knowledge of self-assembly phenomenon.Remarkable thermoreversible self-assembled structures from perfluorinated surface-undecenoated cellulose nanoparticles (FSU-CNPs) with core-coronas structure were formed on the surfaces of self-standing films in dry state. The thermoreversible properties including morphology, birefringence, wetting ability, and transparency can be mutually transformed in dry state via heating at high temperature, such as at 80 °C, and cooling with aging at room temperature.
      PubDate: 2017-10-06T08:59:58.008395-05:
      DOI: 10.1002/adma.201702473
       
  • Giant Room-Temperature Magnetodielectric Response in a MOF at 0.1 Tesla
    • Authors: Li-Hong Chen; Jiang-Bin Guo, Xuan Wang, Xin-Wei Dong, Hai-Xia Zhao, La-Sheng Long, Lan-Sun Zheng
      Abstract: A giant room-temperature magnetodielectric (MD) response upon the application of a small magnetic field is of fundamental importance for the practical application of a new generation of devices. Here, the giant room-temperature magnetodielectric response is demonstrated in the metal–organic framework (MOF) of [NH2(CH3)2]n[FeIIIFeII(1−x)NiIIx(HCOO)6]n (x ≈ 0.63–0.69) (1) with its MD coefficient remaining between −20% and −24% in the 300–410 K temperature range, even at 0.1 T. Because a room-temperature magnetodielectric response has never been observed in MOFs, the present work not only provides a new type of magnetodielectric material but also takes a solid step toward the practical application of MOFs in a new generation of devices.The metal–organic framework of [NH2(CH3)2]n[FeIIIFeII(1−x)NiIIx(HCOO)6]n (x ≈ 0.63–0.69) displays giant room-temperature magnetodielectric response. The magnetodielectric coefficient remains between −20% and −24% in the 300–410 K temperature range, even at 0.1 T. Investigation of the mechanism of its magnetodielectric effect reveals that electron hopping between the NiII ions makes a key contribution to the giant magnetodielectric response.
      PubDate: 2017-10-06T08:58:44.47873-05:0
      DOI: 10.1002/adma.201702512
       
  • Structure-Guided Design and Synthesis of a Mitochondria-Targeting
           Near-Infrared Fluorophore with Multimodal Therapeutic Activities
    • Authors: Xu Tan; Shenglin Luo, Lei Long, Yu Wang, Dechun Wang, Shengtao Fang, Qin Ouyang, Yongping Su, Tianmin Cheng, Chunmeng Shi
      Abstract: An urgent challenge for imaging-guided disease-targeted multimodal therapy is to develop the appropriate multifunctional agents to meet the requirements for potential applications. Here, a rigid cyclohexenyl substitution in the middle of a polymethine linker and two asymmetrical amphipathic N-alkyl side chains to indocyanine green (ICG) (the only FDA-approved NIR contrast agent) are introduced, and a new analog, IR-DBI, is developed with simultaneous cancer-cell mitochondrial targeting, NIR imaging, and chemo-/PDT/PTT/multimodal therapeutic activities. The asymmetrical and amphipathic structural modification renders IR-DBI a close binding to albumin protein site II to form a drug–protein complex and primarily facilitates its preferential accumulation at tumor sites via the enhanced permeability and retention (EPR) effect. The released IR-DBI dye is further actively taken up by cancer cells through organic-anion-transporting polypeptide transporters, and the lipophilic cationic property leads to its selective accumulation in the mitochondria of cancer cells. Finally, based on the high albumin-binding affinity, IR-DBI is modified into human serum albumin (HSA) via self-assembly to produce a nanosized complex, which exhibits significant improvement in the cancer targeting and multimodal cancer treatment with better biocompatibility. This finding may present a practicable strategy to develop small-molecule-based cancer theranostic agents for simultaneous cancer diagnostics and therapeutics.A structure-inherent multifunctional small molecule with simultaneous cancer-cell mitochondrial targeting, NIR imaging, and synchronous PDT/PTT/chemotherapeutic effects is developed. Human serum albumin further enhances its tumor-preferential accumulation through the enhanced permeability and retention effect via self-assembly. This work may present a practicable strategy to develop small-molecule-based cancer theranostic agents with improved tumor targeting for simultaneous cancer diagnostics and therapeutics.
      PubDate: 2017-10-05T05:51:46.188398-05:
      DOI: 10.1002/adma.201704196
       
  • Printable Fabrication of Nanocoral-Structured Electrodes for
           High-Performance Flexible and Planar Supercapacitor with Artistic Design
    • Authors: Yuanjing Lin; Yuan Gao, Zhiyong Fan
      Abstract: Planar supercapacitors with high flexibility, desirable operation safety, and high performance are considered as attractive candidates to serve as energy-storage devices for portable and wearable electronics. Here, a scalable and printable technique is adopted to construct novel and unique hierarchical nanocoral structures as the interdigitated electrodes on flexible substrates. The as-fabricated flexible all-solid-state planar supercapacitors with nanocoral structures achieve areal capacitance up to 52.9 mF cm−2, which is 2.5 times that of devices without nanocoral structures, and this figure-of-merit is among the highest in the literature for the same category of devices. More interestingly, due to utilization of the inkjet-printing technique, excellent versatility on electrode-pattern artistic design is achieved. Particularly, working supercapacitors with artistically designed patterns are demonstrated. Meanwhile, the high scalability of such a printable method is also demonstrated by fabrication of large-sized artistic supercapacitors serving as energy-storage devices in a wearable self-powered system as a proof of concept.Novel and unique hierarchical nanocoral structures as interdigitated electrodes with high density are constructed on flexible substrates via a scalable and printable technique, and the as-fabricated, flexible, all-solid-state planar supercapacitors achieve remarkable performance enhancement. Due to utilization of the inkjet-printing technique, working supercapacitors with excellent versatility on an electrode-pattern artistic design are successfully fabricated.
      PubDate: 2017-10-05T05:50:05.577367-05:
      DOI: 10.1002/adma.201701736
       
  • Surface-Embedded Stretchable Electrodes by Direct Printing and their Uses
           to Fabricate Ultrathin Vibration Sensors and Circuits for 3D Structures
    • Authors: Jun Hyuk Song; Young-Tae Kim, Sunghwan Cho, Woo-Jin Song, Sungmin Moon, Chan-Gyung Park, Soojin Park, Jae Min Myoung, Unyong Jeong
      Abstract: Printing is one of the easy and quick ways to make a stretchable wearable electronics. Conventional printing methods deposit conductive materials “on” or “inside” a rubber substrate. The conductors made by such printing methods cannot be used as device electrodes because of the large surface topology, poor stretchability, or weak adhesion between the substrate and the conducting material. Here, a method is presented by which conductive materials are printed in the way of being surface-embedded in the rubber substrate; hence, the conductors can be widely used as device electrodes and circuits. The printing process involves a direct printing of a metal precursor solution in a block-copolymer rubber substrate and chemical reduction of the precursor into metal nanoparticles. The electrical conductivity and sensitivity to the mechanical deformation can be controlled by adjusting the number of printing operations. The fabrication of highly sensitive vibration sensors is thus presented, which can detect weak pulses and sound waves. In addition, this work takes advantage of the viscoelasticity of the composite conductor to fabricate highly conductive stretchable circuits for complicated 3D structures. The printed electrodes are also used to fabricate a stretchable electrochemiluminescence display.Stretchable electrodes surface-embedded in rubber substrates are fabricated by a simple printing strategy. The process involves printing of a metal precursor and chemical reduction into metal nanoparticles. These printed electrodes are used as highly sensitive free-standing thin-film vibration sensors and highly stretchable electrical circuits for 3D structures.
      PubDate: 2017-10-04T11:43:31.789598-05:
      DOI: 10.1002/adma.201702625
       
  • Efficient Semitransparent Organic Solar Cells with Tunable Color enabled
           by an Ultralow-Bandgap Nonfullerene Acceptor
    • Authors: Yong Cui; Chenyi Yang, Huifeng Yao, Jie Zhu, Yuming Wang, Guoxiao Jia, Feng Gao, Jianhui Hou
      Abstract: Semitransparent organic solar cells (OSCs) show attractive potential in power-generating windows. However, the development of semitransparent OSCs is lagging behind opaque OSCs. Here, an ultralow-bandgap nonfullerene acceptor, “IEICO-4Cl”, is designed and synthesized, whose absorption spectrum is mainly located in the near-infrared region. When IEICO-4Cl is blended with different polymer donors (J52, PBDB-T, and PTB7-Th), the colors of the blend films can be tuned from purple to blue to cyan, respectively. Traditional OSCs with a nontransparent Al electrode fabricated by J52:IEICO-4Cl, PBDB-T:IEICO-4Cl, and PTB7-Th:IEICO-4Cl yield power conversion efficiencies (PCE) of 9.65 ± 0.33%, 9.43 ± 0.13%, and 10.0 ± 0.2%, respectively. By using 15 nm Au as the electrode, semitransparent OSCs based on these three blends also show PCEs of 6.37%, 6.24%, and 6.97% with high average visible transmittance (AVT) of 35.1%, 35.7%, and 33.5%, respectively. Furthermore, via changing the thickness of Au in the OSCs, the relationship between the transmittance and efficiency is studied in detail, and an impressive PCE of 8.38% with an AVT of 25.7% is obtained, which is an outstanding value in the semitransparent OSCs.A new nonfullerene acceptor, IEICO-4Cl, is designed to prepare semitransparent organic solar cells (OSCs), yielding a power conversion efficiency of 8.38% with an average visible transmittance of 25.7%, which is among the top results for semitransparent OSCs.
      PubDate: 2017-10-04T11:43:09.856313-05:
      DOI: 10.1002/adma.201703080
       
  • AIE Nanoparticles with High Stimulated Emission Depletion Efficiency and
           Photobleaching Resistance for Long-Term Super-Resolution Bioimaging
    • Authors: Dongyu Li; Wei Qin, Bin Xu, Jun Qian, Ben Zhong Tang
      Abstract: Stimulated emission depletion (STED) nanoscopy is a typical super-resolution imaging technique that has become a powerful tool for visualizing intracellular structures on the nanometer scale. Aggregation-induced emission (AIE) luminogens are ideal fluorescent agents for bioimaging. Herein, long-term super-resolution fluorescence imaging of cancer cells, based on STED nanoscopy assisted by AIE nanoparticles (NPs) is realized. 2,3-Bis(4-(phenyl(4-(1,2,2-triphenylvinyl)phenyl)amino)phenyl) fumaronitrile (TTF), a typical AIE luminogen, is doped into colloidal mesoporous silica to form fluorescent NPs. TTF@SiO2 NPs bear three significant features, which are all essential for STED nanoscopy. First, their STED efficiency can reach more than 60%. Second, they are highly resistant to photobleaching, even under long-term and high-power STED light irradiation. Third, they have a large Stokes' shift of ≈150 nm, which is beneficial for restraining the fluorescence background induced by the STED light irradiation. STED nanoscopy imaging of TTF@SiO2-NPs-stained HeLa cells is performed, exhibiting a high lateral spatial resolution of 30 nm. More importantly, long-term (more than half an hour) super-resolution cell imaging is achieved with low fluorescence loss. Considering that AIE luminogens are widely used for organelle targeting, cellular mapping, and tracing, AIE-NPs-based STED nanoscopy holds great potential for many basic biomedical studies that require super-resolution and long-term imaging.A star aggregation-induced emission luminogen is doped into silica nanoparticles, which serve as fluorescent probes for stimulated emission depletion (STED) nanoscopy imaging with a high lateral spatial resolution of 30 nm. The nanoparticles are highly resistant to photobleaching, even under long-term and high-power STED light irradiation. Consequently, super-resolution bioimaging is performed for more than half an hour, with low fluorescence loss.
      PubDate: 2017-10-04T11:42:35.765922-05:
      DOI: 10.1002/adma.201703643
       
  • Direct Observation of Halide Migration and its Effect on the
           Photoluminescence of Methylammonium Lead Bromide Perovskite Single
           Crystals
    • Authors: Yanqi Luo; Parisa Khoram, Sarah Brittman, Zhuoying Zhu, Barry Lai, Shyue Ping Ong, Erik C. Garnett, David P. Fenning
      Abstract: Optoelectronic devices based on hybrid perovskites have demonstrated outstanding performance within a few years of intense study. However, commercialization of these devices requires barriers to their development to be overcome, such as their chemical instability under operating conditions. To investigate this instability and its consequences, the electric field applied to single crystals of methylammonium lead bromide (CH3NH3PbBr3) is varied, and changes are mapped in both their elemental composition and photoluminescence. Synchrotron-based nanoprobe X-ray fluorescence (nano-XRF) with 250 nm resolution reveals quasi-reversible field-assisted halide migration, with corresponding changes in photoluminescence. It is observed that higher local bromide concentration is correlated to superior optoelectronic performance in CH3NH3PbBr3. A lower limit on the electromigration rate is calculated from these experiments and the motion is interpreted as vacancy-mediated migration based on nudged elastic band density functional theory (DFT) simulations. The XRF mapping data provide direct evidence of field-assisted ionic migration in a model hybrid-perovskite thin single crystal, while the link with photoluminescence proves that the halide stoichiometry plays a key role in the optoelectronic properties of the perovskite.Bromide-ion migration is directly observed in a methylammonium lead bromide perovskite single crystal under bias using a synchrotron-based X-ray fluorescence nanoprobe. Photoluminescence mapping indicates that bromide-rich regions exhibit enhanced photoluminescence. The close correspondence between the local bromide concentration and photoluminescence in response to bias reveals the importance of non-stoichiometry in determining optoelectronic performance in halide perovskites.
      PubDate: 2017-09-29T12:01:39.704009-05:
      DOI: 10.1002/adma.201703451
       
  • Elastic Inflatable Actuators for Soft Robotic Applications
    • Authors: Benjamin Gorissen; Dominiek Reynaerts, Satoshi Konishi, Kazuhiro Yoshida, Joon-Wan Kim, Michael De Volder
      Abstract: The 20th century's robotic systems have been made from stiff materials, and much of the developments have pursued ever more accurate and dynamic robots, which thrive in industrial automation, and will probably continue to do so for decades to come. However, the 21st century's robotic legacy may very well become that of soft robots. This emerging domain is characterized by continuous soft structures that simultaneously fulfill the role of robotic link and actuator, where prime focus is on design and fabrication of robotic hardware instead of software control. These robots are anticipated to take a prominent role in delicate tasks where classic robots fail, such as in minimally invasive surgery, active prosthetics, and automation tasks involving delicate irregular objects. Central to the development of these robots is the fabrication of soft actuators. This article reviews a particularly attractive type of soft actuators that are driven by pressurized fluids. These actuators have recently gained traction on the one hand due to the technology push from better simulation tools and new manufacturing technologies, and on the other hand by a market pull from applications. This paper provides an overview of the different advanced soft actuator configurations, their design, fabrication, and applications.The 21st century's robotic legacy may very well become that of soft robots, which show remarkable features superior to those of conventional robots in tasks requiring delicate manipulation and a high degree of maneuverability. This review discusses a particular type of soft actuators—elastic inflatable actuators—which are driven by pressurized fluids and allow for straightforward integration in soft robotics.
      PubDate: 2017-09-26T09:18:51.993556-05:
      DOI: 10.1002/adma.201604977
       
  • Robust Catalysis on 2D Materials Encapsulating Metals: Concept,
           Application, and Perspective
    • Authors: Jiao Deng; Dehui Deng, Xinhe Bao
      Abstract: Great endeavors are undertaken to search for low-cost, rich-reserve, and highly efficient alternatives to replace precious-metal catalysts, in order to cut costs and improve the efficiency of catalysts in industry. However, one major problem in metal catalysts, especially nonprecious-metal catalysts, is their poor stability in real catalytic processes. Recently, a novel and promising strategy to construct 2D materials encapsulating nonprecious-metal catalysts has exhibited inimitable advantages toward catalysis, especially under harsh conditions (e.g., strong acidity or alkalinity, high temperature, and high overpotential). The concept, which originates from unique electron penetration through the 2D crystal layer from the encapsulated metals to promote a catalytic reaction on the outermost surface of the 2D crystal, has been widely applied in a variety of reactions under harsh conditions. It has been vividly described as “chainmail for catalyst.” Herein, recent progress concerning this chainmail catalyst is reviewed, particularly focusing on the structural design and control with the associated electronic properties of such heterostructure catalysts, and also on their extensive applications in fuel cells, water splitting, CO2 conversion, solar cells, metal–air batteries, and heterogeneous catalysis. In addition, the current challenges that are faced in fundamental research and industrial application, and future opportunities for these fantastic catalytic materials are discussed.A new catalytic concept is systematically reviewed based on robust catalysts via utilizing electron penetration from encapsulated metal nanoparticles to the surface of 2D materials, described vividly as “chainmail for catalyst.” Furthermore, structural and electronic optimization, including the flexible combination of metal nanoparticles and 2D materials, enrich such a class of catalysts and boost them into more applications.
      PubDate: 2017-09-22T07:17:30.999226-05:
      DOI: 10.1002/adma.201606967
       
  • A Superhydrophobic Smart Coating for Flexible and Wearable Sensing
           Electronics
    • Authors: Lianhui Li; Yuanyuan Bai, Lili Li, Shuqi Wang, Ting Zhang
      Abstract: Superhydrophobic surfaces have shown versatile applications in waterproofing, self-cleaning, drag reduction, selective absorption, etc. The most convenient and universally applicable approach to forming superhydrophobic surfaces is by coating; however, currently, superhydrophobic, smart coatings with flexibility and multiple functions for wearable sensing electronics are not yet reported. Here, a highly flexible multifunctional smart coating is fabricated by spray-coating multiwalled carbon nanotubes dispersed in a thermoplastic elastomer solution, followed by treatment with ethanol. The coatings not only endow various substrate materials with superhydrophobic surfaces, but can also respond to stretching, bending, and torsion—a property useful for flexible sensor applications. The coatings show superior sensitivity (gauge factor of 5.4–80), high resolution (1° of bending), a fast response time (
      PubDate: 2017-09-22T07:12:09.24013-05:0
      DOI: 10.1002/adma.201702517
       
  • Temporal and Remote Tuning of Piezophotonic-Effect-Induced Luminescence
           and Color Gamut via Modulating Magnetic Field
    • Authors: Man-Chung Wong; Li Chen, Gongxun Bai, Long-Biao Huang, Jianhua Hao
      Abstract: Light-emitting materials have been extensively investigated because of their widespread applications in solid-state lighting, displays, sensors, and bioimaging. In these applications, it is highly desirable to achieve tunable luminescence in terms of luminescent intensity and wavelength. Here, a convenient physical approach of temporal and remote tuning of light-emitting wavelength and color is demonstrated, which is greatly different from conventional methods. It is shown that by modulating the frequency of magnetic-field excitation at room temperature, luminescence from the flexible composites of ZnS:Al, Cu phosphors induced by the piezophotonic effect can be tuned in real time and in situ. The mechanistic investigation suggests that the observed tunable piezophotonic emission is ascribed to the tilting band structure of the ZnS phosphor induced by magnetostrictive strain under a high frequency of magnetic-field excitation. Furthermore, some proof-of concept devices, including red–green–blue full-color displays and tunable white-light sources are demonstrated simply by frequency modulation. A new understanding of the fundamentals of both luminescence and magnetic–optics coupling is thus provided, while offering opportunities in magnetic–optical sensing, piezophotonics, energy harvesting, novel light sources, and displays.Temporal tuning of the light-emitting wavelength and color by an in situ and reversible method is presented, which differs greatly from conventional approaches. Red–green–blue and tunable white-light are demonstrated by modulating the frequency of magnetic excitation. A new understanding of the luminescence mechanism is thus determined. The findings will offer opportunities in magnetic–optical sensing, piezophotonics, energy harvesting, novel light sources, and displays.
      PubDate: 2017-09-18T07:31:17.39601-05:0
      DOI: 10.1002/adma.201701945
       
 
 
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