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  Subjects -> CHEMISTRY (Total: 847 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (598 journals)
    - CRYSTALLOGRAPHY (22 journals)
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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 5)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 24)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 15)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 19)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 31)
ACS Nano     Full-text available via subscription   (Followers: 161)
ACS Photonics     Full-text available via subscription   (Followers: 6)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 16)
Acta Chemica Iasi     Open Access  
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 4)
Acta Scientifica Naturalis     Open Access  
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 4)
Advanced Functional Materials     Hybrid Journal   (Followers: 41)
Advanced Science Focus     Free   (Followers: 2)
Advances in Chemical Engineering and Science     Open Access   (Followers: 33)
Advances in Chemical Science     Open Access   (Followers: 10)
Advances in Chemistry     Open Access   (Followers: 8)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 14)
Advances in Drug Research     Full-text available via subscription   (Followers: 21)
Advances in Environmental Chemistry     Open Access   (Followers: 1)
Advances in Enzyme Research     Open Access   (Followers: 4)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 12)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 15)
Advances in Nanoparticles     Open Access   (Followers: 12)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 36)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 13)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 13)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 2)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 12)
American Journal of Chemistry     Open Access   (Followers: 23)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Full-text available via subscription   (Followers: 8)
Anadolu University Journal of Science and Technology     Open Access  
Analyst     Full-text available via subscription   (Followers: 42)
Angewandte Chemie     Hybrid Journal   (Followers: 120)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 169)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 2)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 7)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 8)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Full-text available via subscription  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 5)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 22)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 2)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 4)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 8)
Biochemistry     Full-text available via subscription   (Followers: 211)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 4)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 8)
Bioinspired Materials     Open Access   (Followers: 2)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 17)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 9)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 98)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 90)
Bioorganic Chemistry     Hybrid Journal   (Followers: 9)
Biopolymers     Hybrid Journal   (Followers: 17)
Biosensors     Open Access   (Followers: 1)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal  
C - Journal of Carbon Research     Open Access   (Followers: 2)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 6)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 27)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 5)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 5)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 6)
Cellulose     Hybrid Journal   (Followers: 4)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription  
ChemCatChem     Hybrid Journal   (Followers: 5)
Chemical and Engineering News     Free   (Followers: 11)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 62)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 20)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 17)
Chemical Reviews     Full-text available via subscription   (Followers: 140)
Chemical Science     Open Access   (Followers: 18)
Chemical Technology     Open Access   (Followers: 5)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemical Week     Full-text available via subscription   (Followers: 7)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 53)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 26)
ChemInform     Hybrid Journal   (Followers: 4)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 5)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 2)
Chemistry - A European Journal     Hybrid Journal   (Followers: 115)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 12)
Chemistry and Materials Research     Open Access   (Followers: 14)
Chemistry Central Journal     Open Access   (Followers: 5)
Chemistry Education Research and Practice     Free   (Followers: 4)
Chemistry in Education     Open Access   (Followers: 2)
Chemistry International     Hybrid Journal   (Followers: 1)
Chemistry Letters     Full-text available via subscription   (Followers: 42)
Chemistry of Materials     Full-text available via subscription   (Followers: 147)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 8)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 6)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 25)
Chromatography     Open Access   (Followers: 5)
Chromatography Research International     Open Access   (Followers: 5)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 8)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 17)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Composite Interfaces     Hybrid Journal   (Followers: 3)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 10)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 10)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription  
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 4)
Crystal Structure Theory and Applications     Open Access   (Followers: 2)
CrystEngComm     Full-text available via subscription   (Followers: 6)
Current Catalysis     Hybrid Journal   (Followers: 1)
Current Metabolomics     Hybrid Journal   (Followers: 3)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 7)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 15)
Current Research in Chemistry     Open Access   (Followers: 7)
Current Science     Open Access   (Followers: 19)
Dalton Transactions     Full-text available via subscription   (Followers: 17)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 1)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 3)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 2)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 4)
EDUSAINS     Open Access  
Elements     Full-text available via subscription   (Followers: 1)
Environmental Chemistry     Hybrid Journal   (Followers: 5)

        1 2 3 | Last

Journal Cover Advanced Functional Materials
  [SJR: 4.682]   [H-I: 156]   [41 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1616-301X - ISSN (Online) 1616-3028
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Oxidation‐Resistant and Elastic Mesoporous Carbon with
           Single‐Layer Graphene Walls
    • Abstract: An oxidation‐resistant and elastic mesoporous carbon, graphene mesosponge (GMS), is prepared. GMS has a sponge‐like mesoporous framework (mean pore size is 5.8 nm) consisting mostly of single‐layer graphene walls, which realizes a high electric conductivity and a large surface area (1940 m2 g−1). Moreover, the graphene‐based framework includes only a very small amount of edge sites, thereby achieving much higher stability against oxidation than conventional porous carbons such as carbon blacks and activated carbons. Thus, GMS can simultaneously possess seemingly incompatible properties; the advantages of graphitized carbon materials (high conductivity and high oxidation resistance) and porous carbons (large surface area). These unique features allow GMS to exhibit a sufficient capacitance (125 F g−1), wide potential window (4 V), and good rate capability as an electrode material for electric double‐layer capacitors utilizing an organic electrolyte. Hence, GMS achieves a high energy density of 59.3 Wh kg−1 (material mass base), which is more than twice that of commercial materials. Moreover, the continuous graphene framework makes GMS mechanically tough and extremely elastic, and its mean pore size (5.8 nm) can be reversibly compressed down to 0.7 nm by simply applying mechanical force. The sponge‐like elastic property enables an advanced force‐induced adsorption control. Oxidation‐resistant and elastic mesoporous carbon consisting of single‐layer graphene walls is prepared. The unique framework realizes a large surface area and minimal number of edge sites, thereby making the material promising for the application in electric double‐layer capacitors. The framework is mechanically tough and greatly elastic, enabling an advanced force‐induced adsorption control.
      PubDate: 2016-07-21T08:25:09.485654-05:
      DOI: 10.1002/adfm.201602459
       
  • Ultrafast Plasmonic Hot Electron Transfer in Au Nanoantenna/MoS2
           Heterostructures
    • Authors: Ying Yu; Ziheng Ji, Shuai Zu, Bowen Du, Yimin Kang, Ziwei Li, Zhangkai Zhou, Kebin Shi, Zheyu Fang
      Abstract: 2D transition metal dichalcogenides are becoming attractive materials for novel photoelectric and photovoltaic applications due to their excellent optoelectric properties and accessible optical bandgap in the near‐infrared to visible range. Devices utilizing 2D materials integrated with metal nanostructures have recently emerged as efficient schemes for hot electron‐based photodetection. Metal‐semiconductor heterostructures with low cost, simple procedure, and fast response time are crucial for the practical applications of optoelectric devices. In this paper, template‐based sputtering method is used first to fabricate Au nanoantenna (NA)/MoS2 heterostructures with low cost, simple preparation, broad spectral response, and fast response time. Through the measurement of femtosecond pump‐probe spectroscopy, it is demonstrated that plasmon‐induced hot electron transfer takes place in the Au NA/MoS2 heterostructure on the order of 200 fs with an injected electron density of about 5.6 × 1012 cm−2. Moreover, the pump‐power‐dependent photoluminescence spectra confirm that the exciton energy of MoS2 can be enhanced, coupled, and reradiated by the Au NA. Such ultrafast plasmon‐induced hot electron transfer in the metal‐semiconductor heterostructure can enable novel 2D devices for light harvesting and photoelectric conversion. In this study, the femtosecond pump‐probe technique is used to measure electron transfer of the Au nanoantenna/MoS2 heterostructure, which is fabricated by the template‐based sputtering method with low cost and simple procedures. The results demonstrate that plasmon‐induced hot electron transfer takes place in the heterostructure in the order of 200 fs with an injected electron density of about 5.6 × 1012 cm−2.
      PubDate: 2016-07-21T08:21:44.867399-05:
      DOI: 10.1002/adfm.201601779
       
  • Broadband Photoresponse Enhancement of a High‐Performance t‐Se
           Microtube Photodetector by Plasmonic Metallic Nanoparticles
    • Authors: Kai Hu; Hongyu Chen, Mingming Jiang, Feng Teng, Lingxia Zheng, Xiaosheng Fang
      Abstract: Broadband responsivity enhancement of single Se microtube (Se‐MT) photodetectors in the UV–visible region is presented in this research. The pristine Se‐MT photodetector demonstrates broadband photoresponse from 300 to 700 nm with peak responsivity of ≈19 mA W−1 at 610 nm and fast speed (rise time 0.32 ms and fall time 23.02 ms). To further enhance the responsivity of the single Se‐MT photodetector, Au and Pt nanoparticles (NPs) are sputtered on these devices. In contrast to only enhancement of responsivity in UV region by Pt NPs, broadband responsivity enhancement (≈600% to ≈800%) of the Se‐MT photodetector is realized from 300 to 700 nm by tuning the size and density of Au NPs. The broadband responsivity enhancement phenomena are interpreted by both the surface modification and surface plasmon coupling. The experimental results of this work provide an additional opportunity for fabricating high‐performance UV–visible broadband photodetectors. A broadband photodetector based on a single Se microtube is demonstrated with responsivity of ≈19 mA W−1 at 610 nm and fast speed (rise time 0.32 ms and fall time 23.02 ms). The responsivity of this device is improved by Au nanoparticles via a simple sputtering method and (≈600% to ≈800%) responsivity enhancement is realized within broadband region (300–700 nm).
      PubDate: 2016-07-21T08:21:41.049266-05:
      DOI: 10.1002/adfm.201602408
       
  • Toward High‐Output Organic Vertical Field Effect Transistors: Key
           Design Parameters
    • Authors: Hyukyun Kwon; Mincheol Kim, Hyunsu Cho, Hanul Moon, Jongjin Lee, Seunghyup Yoo
      Abstract: The performance of C60‐based organic vertical field‐effect transistors (VFETs) is investigated as a function of key geometrical parameters to attain a better understanding of their operation mechanism and eventually to enhance their output current for maximal driving capability. To this end, a 2D device simulation is performed and compared with experimental results. The results reveal that the output current scales mostly with the width of its drain electrode, which is in essence equivalent to the channel width in conventional lateral‐channel transistors, but that of the source electrode and the thickness of C60 layers underneath the source electrode also play subtle but important roles mainly due to the source contact‐limited behavior of the organic VFETs under study. With design strategies acquired from this study, a VFET with an on/off ratio of 5.5 × 105 and on‐current corresponding to a channel length of near 1 μm in a conventional lateral‐channel organic field‐effect transistor (FET) is demonstrated, while the drain width of the VFET and the channel width of the lateral‐channel organic FET are the same. The operation mechanism and performance of organic vertical field effect transistors (VFETs) have been investigated. Several key factors are identified such as source/drain electrode widths, source contact resistance, and bottom active layer thickness. With the key parameters, the proposed VFET shows greater performance than conventional organic field‐effect transistors with lateral channel in terms of driving capability.
      PubDate: 2016-07-21T08:10:45.084875-05:
      DOI: 10.1002/adfm.201601956
       
  • Direct Heating Amino Acids with Silica: A Universal Solvent‐Free
           Assembly Approach to Highly Nitrogen‐Doped Mesoporous Carbon
           Materials
    • Authors: Xingmin Gao; Zhi Chen, Yan Yao, Mengyuan Zhou, Yong Liu, Jinxiu Wang, Winston Duo Wu, Xiao Dong Chen, Zhangxiong Wu, Dongyuan Zhao
      Abstract: A general solvent‐free assembly approach via directly heating amino acid and mesoporous silica mixtures is developed for the synthesis of a family of highly nitrogen‐doped mesoporous carbons. Amino acids have been used as the sole precursors for templating synthesis of a series of ordered mesoporous carbons. During heating, amino acids are melted and strongly interact with silica, leading to effective loading and improved carbon yields (up to ≈25 wt%), thus to successful structure replication and nitrogen‐doping. Unique solvent‐free structure assembly mechanisms are proposed and elucidated semi‐quantitatively by using two affinity scales. Significantly high nitrogen‐doping levels are achieved, up to 9.4 (16.0) wt% via carbonization at 900 (700) °C. The diverse types of amino acids, their variable interactions with silica and different pyrolytic behaviors lead to nitrogen‐doped mesoporous carbons with tunable surface areas (700–1400 m2 g−1), pore volumes (0.9–2.5 cm3 g−1), pore sizes (4.3–10 nm), and particle sizes from a single template. As demonstrations, the typical nitrogen‐doped carbons show good performance in CO2 capture with high CO2/N2 selectivities up to ≈48. Moreover, they show attractive performance for oxygen reduction reaction, with an onset and a half‐wave potential of ≈−0.06 and −0.14 V (vs Ag/AgCl). A universal solvent‐free assembly approach via directly heating amino acid/mesoporous silica mixture is developed for the synthesis of a family of nitrogen‐doped mesoporous carbons with tunable physicochemical properties. The underlying structure assembly mechanisms are elucidated by using two affinity scales. The nitrogen contents are among the highest in literature, rendering them efficient for sorption and catalysis.
      PubDate: 2016-07-21T07:40:47.977551-05:
      DOI: 10.1002/adfm.201601640
       
  • Stabilizing Active Edge Sites in Semicrystalline Molybdenum Sulfide by
           Anchorage on Nitrogen‐Doped Carbon Nanotubes for Hydrogen Evolution
           Reaction
    • Abstract: Finding an abundant and cost‐effective electrocatalyst for the hydrogen evolution reaction (HER) is crucial for a global production of hydrogen from water electrolysis. This work reports an exceptionally large surface area hybrid catalyst electrode comprising semicrystalline molybdenum sulfide (MoS2+x) catalyst attached on a substrate based on nitrogen‐doped carbon nanotubes (N‐CNTs), which are directly grown on carbon fiber paper (CP). It is shown here that nitrogen‐doping of the carbon nanotubes improves the anchoring of MoS2+x catalyst compared to undoped carbon nanotubes and concurrently stabilizes a semicrystalline structure of MoS2+x with a high exposure of active sites for HER. The well‐connected constituents of the hybrid catalyst are shown to facilitate electron transport and as a result of the good attributes, the MoS2+x/N‐CNT/CP electrode exhibits an onset potential of −135 mV for HER in 0.5 m H2SO4, a Tafel slope of 36 mV dec−1, and high stability at a current density of −10 mA cm−2. This study reports on how an unusually high number of active edge sites in semicrystalline molybdenum sulfide can be stabilized by anchorage on nitrogen‐doped carbon nanotubes. The hybrid electrode performs well for hydrogen evolution reactions.
      PubDate: 2016-07-21T01:20:43.678438-05:
      DOI: 10.1002/adfm.201601994
       
  • High Sulfur Loading in Hierarchical Porous Carbon Rods Constructed by
           Vertically Oriented Porous Graphene‐Like Nanosheets for Li‐S
           Batteries
    • Authors: Zongmin Zheng; Hongchen Guo, Fei Pei, Xin Zhang, Xinyi Chen, Xiaoliang Fang, Taihong Wang, Nanfeng Zheng
      Abstract: The utilization of porous carbon frameworks as hosts for sulfur loading is an important theme in current Li‐S battery research. Unfortunately, the high loading of insulating sulfur often leads to low specific capacities, poor rate properties, and rapid capacity loss. To address this challenge, a facile templating route to fabricate a novel host material, hierarchical porous carbon rods constructed by vertically oriented porous graphene‐like nanosheets (HPCR) is presented. With a high specific surface area, ultralarge pore volume, hierarchical porous structures, and ideal ion transfer pathways, HPCR is a promising candidate for high sulfur loading. When used as the active material for a sulfur cathode, the HPCR‐S composite with 78.9 wt% sulfur exhibits excellent rate performance (646 mAh g−1sulfur at 5 C) and cycling stability (700 mAh g−1sulfur after 300 cycles at 1 C). Even with a sulfur content of 88.8 wt%, the HPCR‐S composite, without any additional protective polymer coating, still delivers a good rate performance (545 mAh g−1sulfur at 3 C) and cycling stability (632 mAh g−1sulfur after 200 cycles at 1 C). More importantly, the high sulfur loading (88.8 wt%) ensures that the HPCR‐S composite has a high energy density (880 mAh cm−3cathode after 200 cycles at 1 C). Hierarchical porous carbon rods constructed from vertically oriented porous graphene‐like nanosheets are rationally designed and synthesized to fabricate the carbon‐sulfur cathodes with high sulfur content (≈71 wt% of sulfur in the cathode). The developed hierarchical porous structure harvests the promising carbon hosts for advanced Li‐S batteries and provides a new opportunity to upgrade porous graphene for broad applications.
      PubDate: 2016-07-21T01:20:36.593901-05:
      DOI: 10.1002/adfm.201601897
       
  • Localized Excitation of Neural Activity via Rapid Magnetothermal Drug
           Release
    • Authors: Gabriela Romero; Michael G. Christiansen, Ligia Stocche Barbosa, Francisco Garcia, Polina Anikeeva
      Abstract: Hysteretic heat dissipation by magnetic nanoparticles (MNPs) in alternating magnetic fields (AMFs) allows these materials to act as local transducers of external stimuli. Commonly employed in cancer research, MNPs have recently found applications in remote control of heat‐dependent cellular pathways. Here, a thermally labile linker chemistry is adapted for the release of neuromodulatory compounds from the surfaces of MNPs via local nanoscale heating. By examining a range of MNP sizes, and considering individual particle loss powers, AMF conditions and nanomaterials suitable for rapid and complete release of a payload from MNP surfaces are selected. Local release of allyl isothiocyanate, an agonist of the Ca2+ channel TRPV1 (transient receptor potential vanilloid cation channel subfamily member 1), from iron oxide MNPs results in pharmacological excitation of neurons with latencies of ≈12 s. When targeted to neuronal membranes, these MNPs trigger Ca2+ influx and action potential firing at particle concentrations three orders of magnitude less than those previously used for magnetothermal neuromodulation accomplished with bulk heating. Localized heating of magnetic nanoparticles by an alternating magnetic field can trigger the release of a chemical payload from their surfaces by breaking a thermally labile bond within ≈12 s, offering a tool for noninvasive chemical neuromodulation. As a demonstration, neurons expressing a cation channel TRPV1 (transient receptor potential vanilloid cation channel subfamily member 1) are actuated by the local release of allyl isothyocyanate, a TRPV1 agonist.
      PubDate: 2016-07-20T06:20:47.518902-05:
      DOI: 10.1002/adfm.201602189
       
  • Untangling Electrostatic and Strain Effects on the Polarization of
           Ferroelectric Superlattices
    • Abstract: The polarization of ferroelectric superlattices is determined by both electrical boundary conditions at the ferroelectric/paraelectric interfaces and lattice strain. The combined influence of both factors offers new opportunities to tune ferroelectricity. However, the experimental investigation of their individual impact has been elusive because of their complex interplay. Here, a simple growth strategy has permitted to disentangle both contributions by an independent control of strain in symmetric superlattices. It is found that fully strained short‐period superlattices display a large polarization whereas a pronounced reduction is observed for longer multilayer periods. This observation indicates that the electrostatic boundary mainly governs the ferroelectric properties of the multilayers whereas the effects of strain are relatively minor. The modulation of properties in ferroelectric superlattices comes from electrostatic boundary conditions and cell distortions associated with interface‐controlled epitaxial strain, but there is no clear picture of the specific relevance of each of these factors. Using a simple growth strategy, a separate control is achieved, allowing disentangling the relative contribution of electrostatic boundary conditions and strain. It turns out that the former rules the ferroelectric response, meanwhile the influence of the lattice strain is of secondary relevance.
      PubDate: 2016-07-20T01:56:14.040821-05:
      DOI: 10.1002/adfm.201602084
       
  • Metal‐Organic‐Framework‐Based Vaccine Platforms for
           Enhanced Systemic Immune and Memory Response
    • Authors: Yan Zhang; Faming Wang, Enguo Ju, Zhen Liu, Zhaowei Chen, Jinsong Ren, Xiaogang Qu
      Abstract: Nanoparticulate delivery platforms have shown promising advantages for vaccines in many aspects. However, their application was limited so far by lengthy synthetic protocols, the requirement of specific modification of antigen, and by the low efficiency in inducing antigen‐specific cytotoxic T‐lymphocyte responses. This study demonstrates for the first time the construction of metal‐organic‐framework (MOF) based vaccines by encapsulating ovalbumin (OVA) and attaching the cytosine‐phosphate‐guanine oligodeoxynucleotides (CpG ODNs) in/on zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles. The pH responsive decomposition feature enables the system to release the protein antigens and CpG ODNs in the same antigen presenting cells more efficiently. More importantly, in addition to the induction of a potent immune memory response, both in vitro and in vivo experiments show that the vaccines can induce strong humoral and cellular immunity. These findings suggest that the MOF‐based vaccine platforms can be used to produce effective vaccines against a range of ailments, which will facilitate the application of MOFs in biomedical areas. In this paper, metal‐organic‐framework (MOF) based vaccines are fabricated facilely to deliver protein antigens and adjuvants in the same antigen presenting cells. Both in vitro and in vivo experiments demonstrate that the nanocomposites can induce strong humoral, cellular immunity, and potent immune memory response. The MOF‐based vaccine platform can be useful for the prevention and/or therapy of various diseases.
      PubDate: 2016-07-19T07:36:40.892881-05:
      DOI: 10.1002/adfm.201600650
       
  • Hierarchical Directed Self‐Assembly of Diblock Copolymers for
           Modified Pattern Symmetry
    • Authors: Young Joo Choi; Ju Young Kim, Ji Eun Kim, Jeong Ho Mun, Seung Keun Cha, Sang Ouk Kim
      Abstract: Block copolymer lithography exploiting diblock copolymer thin films is promising for scalable manufacture of device‐oriented nanostructures. Nonetheless, its intrinsic limitation in the degree of freedom for pattern symmetry within hexagonal dot or parallel line array greatly diminishes the potential application fields. Here, we report multi‐level hierarchical self‐assembled nanopatterning of diblock copolymers for modified pattern symmetry. Sequential hierarchical integration of two layers of diblock copolymer films with judiciously chosen molecular weights and chemical composition creates nanopatterned morphology with modified pattern symmetry, including sparse linear cylinder or lamellar arrays. Internal structure of the hierarchically patterned morphology is characterized by grazing‐incidence small‐angle X‐ray scattering throughout the film thickness. Pattern transfer of the modified nanopattern generates linear metal nanodot array with uniform size and regular spacing as a typical example of functional nanopatterned structures. Symmetry‐modified poly(styrene)‐block‐poly(methyl methacrylate) and poly(styrene)‐block‐poly(4‐vinylpyridine) diblock copolymer patterns generated via a hierarchical self‐assembly principle are presented. Nanoscale and organic cross‐linked PS template prepared from the first layer of block copolymer (BCP) guides the orientation and positional ordering of secondary BCP layer elaborately. This methodology has potential to extend the range of directed self‐assembly by further scaling‐down providing great promise for sub‐10‐nm patterning technology.
      PubDate: 2016-07-19T07:36:36.129521-05:
      DOI: 10.1002/adfm.201601471
       
  • Ultrahigh Gain Polymer Photodetectors with Spectral Response from UV to
           Near‐Infrared Using ZnO Nanoparticles as Anode Interfacial Layer
    • Authors: Xiaokang Zhou; Dezhi Yang, Dongge Ma, Agafonov Vadim, Tansir Ahamad, Saad M. Alshehri
      Abstract: Significant increase of photocurrent upon UV light exposure is demonstrated in a narrow‐bandgap polymer‐based photodetector using ZnO nanoparticles as anode interfacial layer. The phenomenon is attributed to the UV light illumination induced oxygen molecules desorption from surface of ZnO nanoparticles, which reduces the electron injection barrier at the anode interface. Ultrahigh external quantum efficiency of 140 000% and extremely low gain threshold voltage of 1.5 mV are achieved in this device with 30 s UV light irradiation. The gain mechanism is explained by the fast transit and replenishment of photogenerated electrons within their lifetime, which is prolonged by the electron‐only device structure, and the experiment results fit well with the proposed photoconductive model. Significant increase in photoresponse over a wavelength range from 300 to 1000 nm upon UV light illumination is enabled by a thin interfacial layer of ZnO nanoparticles. The device with 30 s UV light treatment shows ultrahigh external quantum efficiency of 140 000% and an extremely low gain threshold voltage of 1.5 mV. This is among the best reported broad spectral response photodetectors.
      PubDate: 2016-07-19T07:36:30.032496-05:
      DOI: 10.1002/adfm.201601980
       
  • Luminescent Ions in Advanced Composite Materials for Multifunctional
           Applications
    • Abstract: Luminescent ions doped materials have been widely applied in many areas, both scientific research and practical fields. Recently, incorporating luminescent ions and advanced materials into versatile and multifunctional systems seems to be a tendency, motivated by the stimulating desires of fundamental studies and technological applications. This feature article provides a general overview of the myriad of luminescent ions‐based advanced composite materials recently investigated. It is demonstrated that the improved or additional properties may be achieved via implementing a strategy of incorporating luminescent ions (lanthanide, transition and main group metal ions) into various types of materials, such as flexible polymers, two‐dimensional atomically thin layers, porous materials, and so on. We outline the design principles, synthesis and processing of various systems joined by luminescent ions doped phosphors. A number of recent works indicate that those novel composite materials allow one to conceive and develop multifunctional applications in a broad area, including optoelectronics, photonics, clean energy, biomedicine, and new types of sensors. Lastly, some challenging issues are discussed and potential directions are suggested for further developing advanced composite materials incorporated with luminescent ions. Integrating luminescent ions and advanced materials into multifunctional systems seems to be a tendency, motivated by the stimulating desires of fundamental studies and technological applications. This feature article provides a general overview of luminescent ions‐based advanced composite materials recently investigated, which have promising multifunctional applications in a broad area, including optoelectronics, photonics, clean energy, biomedicine, and new types of sensors.
      PubDate: 2016-07-19T07:36:04.339791-05:
      DOI: 10.1002/adfm.201602142
       
  • 10.8% Efficiency Polymer Solar Cells Based on PTB7‐Th and PC71BM via
           Binary Solvent Additives Treatment
    • Authors: Qun Wan; Xia Guo, Zaiyu Wang, Wanbin Li, Bing Guo, Wei Ma, Maojie Zhang, Yongfang Li
      Abstract: In this work, polymer solar cells are fabricated based on the blend of PTB7‐Th: PC71BM by using a mixed solvent additive of 1,8‐diiodooctane and N‐methyl pyrrolidone to optimize the morphology of the blend. A high power conversion efficiency (PCE) of 10.8% has been achieved with a simple conventional device. In order to deeply investigate the influence of the mixed solvent additives on the morphology and device performance, the variations of the molecular packing and bulk morphology of the blend film cast from ortho‐dichlorobenzene with single or binary solvent additives are measured. Although all the blend films exhibit similar domain size and nanoscale phase separation, the blend film processed with mixed solvent additive shows the highest domain purity, resulting in the least bimolecular recombination, relatively high Jsc and FF, and hence enhanced PCE. Therefore, the best photovoltaic performance with the Voc of 0.82 V, Jsc of 19.1 mA cm−2, FF of 69.1%, and PCE of 10.8% are obtained for the device based on the blend with binary solvent additive treatment. For the PTB7‐Th:PC71BM blend system, the binary solvent additives of 1,8‐diiodooctane and N‐methyl pyrrolidone are used to enhance the domain purity, so that a power conversion efficiency of 10.8% is achieved with the conventional device structure, which is much higher than that of the devices without or with single solvent additive treatment.
      PubDate: 2016-07-19T07:35:52.906688-05:
      DOI: 10.1002/adfm.201602181
       
  • Patterned Growth of P‐Type MoS2 Atomic Layers Using Sol–Gel as
           Precursor
    • Authors: Wei Zheng; Junhao Lin, Wei Feng, Kai Xiao, Yunfeng Qiu, XiaoShuang Chen, Guangbo Liu, Wenwu Cao, Sokrates T. Pantelides, Wu Zhou, PingAn Hu
      Abstract: 2D layered MoS2 has drawn intense attention for its applications in flexible electronic, optoelectronic, and spintronic devices. Most of the MoS2 atomic layers grown by conventional chemical vapor deposition techniques are n‐type due to the abundant sulfur vacancies. Facile production of MoS2 atomic layers with p‐type behavior, however, remains challenging. Here, a novel one‐step growth has been developed to attain p‐type MoS2 layers in large scale by using Mo‐containing sol–gel, including 1% tungsten (W). Atomic‐resolution electron microscopy characterization reveals that small tungsten oxide clusters are commonly present on the as‐grown MoS2 film due to the incomplete reduction of W precursor at the reaction temperature. These omnipresent small tungsten oxide clusters contribute to the p‐type behavior, as verified by density functional theory calculations, while preserving the crystallinity of the MoS2 atomic layers. The Mo containing sol–gel precursor is compatible with the soft‐lithography techniques, which enables patterned growth of p‐type MoS2 atomic layers into regular arrays with different shapes, holding great promise for highly integrated device applications. Furthermore, an atomically thin p–n junction is fabricated by the as‐prepared MoS2, which shows strong rectifying behavior. A novel one‐step growth process has been developed to obtain p‐type MoS2 layers in large scale by using Mo‐containing sol–gel, including 1% tungsten (W). This method is compatible with soft‐lithography techniques, which enables patterned growth of p‐type MoS2 atomic layers into regular arrays with different shapes, holding great promise for highly integrated device applications.
      PubDate: 2016-07-19T07:35:49.806019-05:
      DOI: 10.1002/adfm.201602494
       
  • Biodegradable Photothermal and pH Responsive Calcium
           Carbonate@Phospholipid@Acetalated Dextran Hybrid Platform for Advancing
           Biomedical Applications
    • Abstract: A biodegradable multifunctional carrier for combination therapy with high efficiency and low side effect is essential for effective cancer treatment and for advancing biomedical applications. Therapeutics combination could reduce multidrug resistance and minimize doses through synergism. This study develops biodegradable gold nanorods@calcium carbonate particles coated with pH‐responsive acetalated dextran and phospholipid as an advanced platform for the incorporation of versatile molecular targeted therapeutics, including hydrophilic and hydrophobic drugs, as well as the model enzyme, green fluorescent protein, or antibody. The developed calcium carbonate based hybrid particles show good biocompatibility, stability with photothermal, and pH responsiveness, which protect the payloads from premature release, and maintain the enzyme activity. The therapeutics co‐loaded CaCO3 based hybrid particles efficiently induce cancer cell death and reduce the multidrug resistance and HER2 expression with synergism. The photothermal effects promote ultrafast therapeutics release and induce significant cytotoxicity. Importantly, Anti‐HER2 antibody or HER2 targeted therapeutic is more effective in reducing HER2 expression when combined with drug or drugs via synergism. Overall, the cheap and simply manufactured biodegradable hybrid platform has great potential for advancing biomedical applications, including targeted photothermal combination therapy by co‐delivery of different types of therapeutics, including molecular targeted drugs, antibodies, and enzymes. The biodegradable photothermal and pH responsive CaCO3@Phospholipid@Acetalated Dextran hybrid platform is developed for advancing biomedical applications by co‐delivery of versatile molecular targeted therapeutics, enzyme, and antibody. The versatile therapeutics co‐loaded AuNRs@CaCO3‐POPC‐AcDX hybrid platform could effectively promote cancer cell death and reduce the multidrug resistance and HER2 expression with synergism.
      PubDate: 2016-07-19T07:35:31.301187-05:
      DOI: 10.1002/adfm.201602715
       
  • Masthead: (Adv. Funct. Mater. 27/2016)
    • PubDate: 2016-07-19T01:10:19.750807-05:
      DOI: 10.1002/adfm.201670172
       
  • Magnetic Mesoporous Nanocarriers for Drug Delivery with Improved
           Therapeutic Efficacy
    • Abstract: Mesoporous CoNi@Au core@shell nanorods are synthesized as magnetic drug nanocarriers by electrodeposition using ionic liquid‐in‐aqueous microemulsions. Mesoporous nanorods present a highly effective area (186 m2 g−1) and magnetic character that allows their manipulation, concentration, and retention by applying a magnetic field. The nanorods have been functionalized with thiol‐poly(ethyleneglycol) molecules, and molecules of Irinotecan, a drug used in chemotherapy, are retained in both the lattice of the linked thiol‐poly(ethyleneglycol) molecules and inside the interconnected nanorods pores. The nanorods' mesoporous character allows a high drug‐loading capability and magnetic behavior that allows the drug's controlled release. A high cellular viability of HeLa cells is obtained after their incubation with the nanorods functionalized with thiol‐poly(ethyleneglycol). However, when the nanorods function as carriers for Irinotecan, significant cell death is occurred when HeLa cells are incubated with the functionalized, drug‐loaded nanorods. Cell death is also produced by applying an alternating magnetic field due to both the effect of the release of Irinotecan from the carrier as to mechanical damage of cells by nanorods subjected to the effect of a magnetic field. The proposal to used mesoporous magnetic nanorods as drug carriers can thus dramatically reduce the amounts of both nanocarrier and drug needed to efficiently destroy cancer cells. A new versatile and simple procedure to grow magnetic mesoporous nanorods is proposed, that produces magnetic drug nanocarriers with excellent drug‐loading and improved therapeutic efficacy. The nanostructures exhibit low toxicity but, when loaded with a carcinogenic drug, induce cell death as a combination of both mechanically and drug‐induced death, making them excellent candidates for drug delivery.
      PubDate: 2016-07-18T09:11:03.66959-05:0
      DOI: 10.1002/adfm.201601473
       
  • Printing Ultrasensitive Artificially Intelligent Sensors Array with a
           Single Self‐Propelled Droplet Containing Nanoparticles
    • Abstract: The fabrication and implementation of artificially intelligent sensor arrays has faced serious technical and/or cost‐effectiveness challenges. Here, a new printing method is presented to produce a fully functional array of sensors based on monolayer‐capped gold nanoparticles. The proposed printing technique is based on the so‐called self‐propelled antipinning ink droplet, from which evaporative deposition takes place along the path of motion. By applying actuating forces, different deposition line patterns with different thicknesses and morphology from a single droplet are generated. The functionality of the produced sensors is demonstrated by their ability to detect different representative volatile organic compounds (VOCs) belonging to different chemical families, including alcohols, alkanes, ethers, and aromatics, and under extremely different humidity levels resembling those encountered in real‐world conditions. The results show that the sensors exhibit ultrasensitive sensing features, with an ability to detect and differentiate between different VOCs at low ppb levels. Additionally, the results show that the sensors are able to accurately predict VOC concentrations, viz. enable quantification capabilities, while nevertheless being inexpensive, do not need complicated and expensive printing equipment and prepatterning processes, allow low voltage operation, and provide a platform for multifunctional applications. Single self‐propelled and evaporative droplets containing molecularly capped nanoparticles are used to produce artificially intelligent sensors array without the need to use complicated printing techniques. The sensors exhibit ultrasensitive sensing performance with an ability to detect and differentiate between various volatile organic compounds at low ppb levels and under extreme humidity confounding environments.
      PubDate: 2016-07-18T09:10:49.56036-05:0
      DOI: 10.1002/adfm.201602326
       
  • Organic Dye Graphene Hybrid Structures with Spectral Color Selectivity
    • Authors: Yu Seong Gim; Youngbin Lee, Soo Kim, Shiqiang Hao, Moon Sung Kang, Won Jong Yoo, Hyunmin Kim, Chris Wolverton, Jeong Ho Cho
      Abstract: This study characterizes a hybrid structure formed between graphene and organic dye molecules for use in photodetectors with spectral color selectivity. Rhodamine‐based organic dye molecules with red, green, or blue light absorption profiles are deposited onto a graphene surface by dip‐coating. UV–vis absorption spectroscopy, charge transport measurements, and density functional theory based calculations reveal that the photoresponses of the dye graphene hybrid films are governed by the light absorption of the dye molecules and also by the photo‐excited‐charge‐transfer‐induced photocurrent gain. The hybrid films respond only to photons with an energy exceeding the band gap of the immobilized dye. Dye‐Graphene charge transfer is affected by the distance and direction of the dipole moment between the two layers. The resulting hybrid films exhibit spectral color selectivities with responsivities of ≈103 A W−1 and specific detectivities of ≈1010 Jones. This study demonstrates the successful operation of photodetectors with a full‐color optical bandwidth using hybrid graphene structures coated with a mixture of dyes. The strategy of building a simple hybrid photodetector can further offer many opportunities to be also tuned for other optical functionalities using a variety of commercially available dye molecules. The hybrid structures formed between graphene and organic dye molecules are characterized for use in photodetectors with spectral color selectivity. The adsorption of dye molecules onto the graphene surfaces and the photoresponse of the resulting hybrid films are investigated systematically using UV–vis absorption spectroscopy, charge transport measurements, and density functional theory based theoretical calculations.
      PubDate: 2016-07-18T09:10:32.745629-05:
      DOI: 10.1002/adfm.201601200
       
  • Dual‐Encoded Microbeads through a Host–Guest Structure:
           Enormous, Flexible, and Accurate Barcodes for Multiplexed Assays
    • Abstract: Bead‐based suspension arrays have attracted increasing attention because of the fast growing requirements for high‐throughput multiplexed bioassays. Here, novel dual‐encoded microbeads (DEBs) based on a host–guest structure are developed. A strawberry‐like structure composed of thousands of dye‐doped nanoparticles closely packed onto the quantum dot‐encoded microbeads is designed and synthesized. Using this 3D structure, the encoded space is fully developed for multicolor encoding. As a result, a 30‐barcode library with an outstanding encoding capacity is successfully established and easily decoded via flow cytometry. The separation of organic dyes and quantum dots into two building blocks helps circumvent the optical mutual interference commonly observed in most multicolor barcodes, bringing great convenience for next‐step decoding accuracy. As a proof of concept, six typical DEBs are chosen and their feasibility in six‐plexed detection for influenza viruses is evaluated. The results show that DEBs can selectively capture the specific targets, with negligible nonspecific absorption; these results thus demonstrate the strong potential of the DEBs as a robust platform for multiplexed bioassays. Dual‐encoded microbeads with a host–guest structure are successfully designed using a controllable, flexible, and accurate encoding strategy. The tailored host–guest structure improves the encoding capacity of the barcodes and effectively overcomes the optical mutual interference. The effectiveness of the barcodes as a robust platform for multiplexed bioassays is demonstrated.
      PubDate: 2016-07-18T01:40:48.573383-05:
      DOI: 10.1002/adfm.201601963
       
  • Imprinting of Local Metallic States into VO2 with Ultraviolet Light
    • Abstract: Materials exhibiting electronic phase transitions have attracted widespread attention. By switching between metallic and insulating states under external stimuli, the accompanying changes in the electrical and optical properties can be harnessed in novel electronic and optical applications. In this work, a laterally confined conductive pattern is inscribed into an otherwise insulating VO2 thin film using ultraviolet light, inducing an almost four orders of magnitude decrease in electrical resistivity of the exposed area. The metallic imprint remains in VO2 after ultraviolet light exposure and can be completely erased by a short low temperature anneal. The ability to optically pattern confined metallic structures provides new opportunities for reconfigurable photonic and plasmonic structures, as well as re‐writable electric circuitry. A laterally confined conductive pattern is inscribed into an otherwise insulating VO2 matrix using ultraviolet light, with almost four orders of magnitude decrease in electrical resistivity. The conductive pattern is persistent and can be completely erased by a short annealing. Optical patterning of locally confined metallic structures provides new opportunities in photonics, plasmonics and electronics, such as reconfigurable bottom electrode.
      PubDate: 2016-07-18T01:40:29.04493-05:0
      DOI: 10.1002/adfm.201601890
       
  • Photoinduced Topographical Feature Development in Blueprinted
           Azobenzene‐Functionalized Liquid Crystalline Elastomers
    • Abstract: All‐optical deformation and recovery of complex topographical features is demonstrated within elastic sheets composed of main‐chain type azobenzene‐functionalized liquid crystalline elastomers (azo‐LCEs). The azo‐LCEs are synthesized via an orthogonal, two‐step reaction between commercially available LC monomers and n‐butylamine. By employing surface alignment, the local orientation of the nematic director is spatially complex (“blueprinted”). Exposing the blueprinted LCE films to light as an actinic stimulus generates a photomechanical response which yields reversible shape changes between 2D and 3D shapes. The deformation of azo‐LCEs strongly depends on the azobenzene concentration as well as the network structure (i.e., crosslink density). Blueprinting complex director profiles within azo‐LCEs yield reconfigurable elastic sheets that can be addressed both remotely and selectively which may have benefit in a variety of applications in aerospace, medicine, and optics. All‐optical deformation and recovery of complex 3D topographical features that can be addressed both remotely and selectively is demonstrated in blueprinted azobenzene‐functionalized liquid crystalline elastomers. The photoinduced shape transformation strongly depends on the azobenzene concentration as well as the network structure (i.e., crosslink density).
      PubDate: 2016-07-15T06:02:27.63572-05:0
      DOI: 10.1002/adfm.201601090
       
  • Selective Photothermal Tumor Therapy Using Nanodiamond‐Based
           Nanoclusters with Folic Acid
    • Abstract: This paper describes the fabrication and evaluation of folic acid (FA)‐conjugated nanodiamond (ND) nanoclusters for selective photothermal tumor therapy. ND nanoclusters with surface carboxyl groups are aminated using ethylenediamine and conjugated with FA via carbodiimide chemistry. The temperature of an aqueous ND dispersion (10 μg mL−1) is increased to 54 °C upon laser exposure for 5 min. FA‐ND nanoclusters are preferentially taken up by KB cells (folate receptor positive) compared to WI‐38 (folate receptor negative) cells, suggesting specificity for tumor cells that overexpress folate receptors. Cell viability tests reveal that FA‐ND nanoclusters effectively and selectively ablate KB cells upon near‐infrared (NIR) laser exposure. In addition, fluorescence microscopy images confirm that only KB cells treated with FA‐ND nanoclusters are ablated in a spot (200 μm in diameter) by NIR laser exposure. In an animal model, a large amount of FA‐ND nanoclusters is accumulated into tumor tissue, resulting in dramatically reduced tumor volume post‐NIR laser exposure as compared to ND nanoclusters. Nanodiamond (ND)‐based nanoclusters with folic acid at their surface have been fabricated for selective photothermal tumor therapy. The ND‐based nanoclusters are photothermal active enough to selectively ablate tumor cells upon a near‐infrared laser exposure at a high resolution. Animal study confirms their effective accumulation into tumor tissue and reduction in tumor volume by laser exposure.
      PubDate: 2016-07-15T06:02:11.927012-05:
      DOI: 10.1002/adfm.201601207
       
  • Silk Fibroin–Substrate Interactions at Heterogeneous Nanocomposite
           Interfaces
    • Authors: Anise M. Grant; Ho Shin Kim, Trisha L. Dupnock, Kesong Hu, Yaroslava G. Yingling, Vladimir V. Tsukruk
      Abstract: Silk fibroin adsorption at the heterogeneous hydrophobic–hydrophilic surface of graphene oxide (GO) with different degrees of oxidation is addressed experimentally and theoretically. Samples are prepared using various spin‐assisted deposition conditions relevant to assembly of laminated nanocomposites from graphene‐based components, and compared with silicon dioxide (SiO2) as a benchmark substrate. Secondary structure of silk backbones changes as a function of silk fibroin concentration, substrate chemical composition, and deposition dynamics are assessed and compared with molecular dynamic simulations. It is observed that protofibrils form at low concentrations while variance in the deposition speed has little effect on silk secondary structure and morphology. However, balance of nonbonded interactions between electrostatic and van der Waals contributions can lead to silk secondary structure retention on the GO surface. Molecular dynamics simulations of silk fibroin at different surfaces show that strong van der Waals interactions play a pivotal role in losing and disrupting secondary structure on graphene and SiO2 surfaces. Fine tuning silk fibroin structure on heterogeneous graphene‐based surfaces paves the way toward development of biomolecular reinforcement for biopolymer–graphene laminated nanocomposites. Tunable assembly of silk on heterogeneous graphitic surfaces is shown as a function of various factors. Shear induces silk alignment into individual fibrils on hydrophilic graphene oxide (GO), while silk maintains its solution state globule‐like morphology on hydrophobic reduced GO. Molecular dynamics simulations combined with high resolution atomic force microscopy are used to explore the nonbonded interactions behind this behavior.
      PubDate: 2016-07-14T09:01:48.723474-05:
      DOI: 10.1002/adfm.201601268
       
  • Enhanced Light Harvesting in Mesoscopic Solar Cells by Multilevel
           Multiscale Patterned Photoelectrodes with Superpositioned Optical
           Properties
    • Abstract: Investigations on nano‐ and micropatterns have been intensively performed in optical applications due to their light modulation effects for enhanced photon utilization. Recently, incorporation of periodic architectures in solar cells have brought significant enhancements in light harvesting and energy conversion efficiency, however, further improvements in performance are required for practical applications due to the intrinsic limitations of single‐level patterns. Herein, this study reports mesoscopic solar cells employing photoelectrodes with multilevel multiscale patterns. Polydimethylsiloxane film with multilevel nano/micropatterns (integrated in z‐axis direction) is prepared by LEGO‐like multiplex lithography, and its architecture is imprinted on mesoporous TiO2 electrode by soft molding technique. By various spectral analyses and simulations, advanced light harvesting properties by superposition of optical responses from constituent nano‐ and micropatterns are verified. The effectiveness of the strategy is confirmed by applications in dye‐sensitized solar cells as a model system, wherein over 17.5% increase in efficiency (by multilevel 400 nm line/20 μm dot structures) is observed. Also, external quantum efficiencies clearly exhibit that the improved light harvesting originates from the combined effects of diffraction grating and random scattering induced by both nano‐ and microarchitectures, respectively. Moreover, the validity of the multiscale approach in different dimensions is also confirmed in order to demonstrate the general advantages. LEGO‐like multilevel multiscale patterns prepared by multiplex lithography are imprinted on the photoelectrode of mesoscopic solar cells. Enhanced light harvesting by superposition of diffraction grating and scattering are achieved by z‐axis integration of nano‐ and micropatterns, respectively, and this leads to significant increase in energy conversion efficiency.
      PubDate: 2016-07-14T09:01:41.919472-05:
      DOI: 10.1002/adfm.201601586
       
  • Quaternized Silicon Nanoparticles with Polarity‐Sensitive
           Fluorescence for Selectively Imaging and Killing Gram‐Positive
           Bacteria
    • Abstract: With the emergence of antibiotic resistance, developing new antibiotics and therapies for combating bacterial infections is urgently needed. Herein, a series of quaternized fluorescent silicon nanoparticles (SiNPs) are facilely prepared by the covalent reaction between amine‐functionalized SiNPs and carboxyl‐containing N‐alkyl betaines. It is found that the bactericidal efficacy of these quaternized SiNPs increases with the length of the N‐alkyl chain, and SiNPs conjugated with N,N‐dimethyl‐N‐octadecylbetaine (BS‐18), abbreviated as SiNPs‐C18, show the best antibacterial effect, whose minimum inhibitory concentrations for Gram‐positive bacteria are 1–2 μg mL−1. In vivo tests further confirm that SiNPs‐C18 have excellent antibacterial efficacy and greatly reduce bacterial load in the infectious sites. The SiNPs‐C18 exhibit low cytotoxicity toward mammalian cells (including normal liver and lung cells, red blood cells, and macrophages), enabling them to be useful for clinical applications. Besides, the quaternized SiNPs exhibit polarity‐dependent fluorescence emission property and can selectively image Gram‐positive bacteria, thereby providing a simple method to successfully differentiate Gram‐positive and Gram‐negative bacteria. The present work represents the first example that successfully turns fluorescent SiNPs into metal‐free NP‐based antibiotics with simultaneous bacterial imaging and killing capability, which broadens the applications of fluorescent SiNPs and advances the development of novel antibacterial agents. A simple and efficient method is developed based on fluorescent quaternized silicon nanoparticles (SiNPs) to meet the increasing demands of bacterial differentiation and metal‐free NP‐based antibiotics. The quaternized SiNPs with polarity‐dependent fluorescence emission possess superb selectivity to image and kill Gram‐positive bacteria over Gram‐negative ones. The low cytotoxicity of quaternized SiNPs enables them for future clinical application.
      PubDate: 2016-07-14T09:01:34.985342-05:
      DOI: 10.1002/adfm.201602185
       
  • Bio‐Derived Polymers for Sustainable Lithium‐Ion Batteries
    • Authors: Tyler B. Schon; Andrew J. Tilley, Colin R. Bridges, Mark B. Miltenburg, Dwight S. Seferos
      Abstract: Biologically derived organic molecules are a cost‐effective and environmentally benign alternative to the widely used metal‐based electrodes employed in current energy storage technologies. Here, the first bio‐derived pendant polymer cathode for lithium‐ion batteries is reported. The redox moiety is flavin and is derived from riboflavin (vitamin B2). A semi‐synthetic methodology is used to prepare the pendant polymer, which is composed of a poly(norbornene) backbone and pendant flavin units. This semi‐synthetic approach reduces the number of chemical transformations required to form this new functional material. Lithium‐ion batteries incorporating this polymer have a 125 mAh g−1 capacity and an ≈2.5 V operating potential. It is found that charge transport is greatly improved by forming hierarchical structures of the polymer with carbon black, and new insight into electrode degradation mechanisms is provided which should be applicable to polymer electrodes in general. This work provides a foundation for the use of bio‐derived pendant polymers in sustainable, high‐performance lithium‐ion batteries. A pendant polymer with bio‐derived redox units is designed for lithium‐ion battery cathodes. With a working voltage of ≈2.5 V versus Li/Li+, it can deliver a high capacity of 125 mAh g−1 at 14.4 mA g−1. Using a semi‐synthetic approach for designing pendant redox‐active polymers is an attractive strategy for the development of energy storage materials.
      PubDate: 2016-07-14T09:01:27.915132-05:
      DOI: 10.1002/adfm.201602114
       
  • Dye Modification of Nanofibrous Silicon Oxide Membranes for Colorimetric
           HCl and NH3 Sensing
    • Authors: Jozefien Geltmeyer; Gertjan Vancoillie, Iline Steyaert, Bet Breyne, Gabriella Cousins, Kathleen Lava, Richard Hoogenboom, Klaartje De Buysser, Karen De Clerck
      Abstract: Colorimetric sensors for monitoring and visual reporting of acidic environments both in water and air are highly valuable in various fields, such as safety and technical textiles. Until now sol‐gel‐based colorimetric sensors are usually nonflexible bulk glass or thin‐film sensors. Large‐area, flexible sensors usable in strong acidic environments are not available. Therefore, in this study organically modified silicon oxide nanofibrous membranes are produced by combining electrospinning and sol‐gel technology. Two pH‐indicator dyes are immobilized in the nanofibrous membranes: methyl yellow via doping, methyl red via both doping, and covalent bonding. This resulted in sensor materials with a fast response time and high sensitivity for pH‐change in water. The covalent bond between dye and the sol‐gel network showed to be essential to obtain a reusable pH‐sensor in aqueous environment. Also a high sensitivity is obtained for sensing of HCl and NH3 vapors, including a memory function allowing visual read‐out up to 20 min after exposure. These fast and reversible, large‐area flexible nanofibrous colorimetric sensors are highly interesting for use in multiple applications such as protective clothing and equipment. Moreover, the sensitivity to biogenic amines is demonstrated, offering potential for control and monitoring of food quality. Large‐area flexible colorimetric sensors for fast and accurate detection of pH‐changes in aqueous solution or gaseous form are developed. By immobilization of pH‐sensitive dyes and by combining electrospinning with sol‐gel technology, highly sensitive and reusable sensors are obtained, which are ideal for sensing low concentrations of HCl and NH3 vapors.
      PubDate: 2016-07-14T09:01:23.801159-05:
      DOI: 10.1002/adfm.201602351
       
  • Soft Nanostructured Films for Actuated Surface‐Based siRNA Delivery
    • Authors: Minjee Kang; Cecilia Leal
      Abstract: Substrate‐mediated gene delivery is an emerging technology that enables spatial control of gene expression and localized delivery. This is of particular interest for siRNA where surface‐based release can greatly impact the fields of stem‐cell reprograming, wound healing, and medical device coatings in general. However, reports on the use of siRNA for substrate‐mediated delivery are scarce and have suffered from low efficiency. Here, an alternative strategy is reported by designing self‐assembled substrates that experience stimuli‐responsive topological transformations. Specifically, a methodology is established to promote the molecular organization of lipid films having 3D‐bicontinuous cubic, 2D‐inverted hexagonal, or 1D‐lamellar nanostructures encapsulating siRNA. In response to a compositional, temperature, or humidity stimulus, the nanostructures evolve from 1D‐lamellar or 2D‐hexagonal to 3D‐cubic resulting in efficient siRNA release to human cell cultures. Grazing incidence X‐ray diffraction reveals that film nanostructures are highly ordered and preferentially aligned. The results indicate that film structure substantially affects siRNA delivery, with the supported 3D‐bicontinuous cubic phase yielding the most effective reduction of gene expression. Subsequent studies suggest this enhanced performance arises due to the ability of this phase to cross cell membranes, particularly those of endocytic compartments. This work underpins that nanostructure tuning is decisive to the performance of therapeutic films. Lipid‐siRNA materials self‐assemble into different nanostructures onto substrates as a function of composition and environmental cues. This feature highlights the potential of using reversible transformations in lipid film materials for actuated surface‐based cellular delivery. The diffusion of biomolecules is enhanced from 1D in lamellar and hexagonal phases to 3D in bicontinuous cubic phases by hydration at 37 °C.
      PubDate: 2016-07-12T07:00:46.59645-05:0
      DOI: 10.1002/adfm.201600681
       
  • Electro‐Oxidation of Ni42 Steel: A Highly Active Bifunctional
           Electrocatalyst
    • Abstract: Janus type water‐splitting catalysts have attracted highest attention as a tool of choice for solar to fuel conversion. AISI Ni42 steel is upon harsh anodization converted into a bifunctional electrocatalyst. Oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly efficiently and steadfast catalyzed at pH 7, 13, 14, 14.6 (OER) and at pH 0, 1, 13, 14, 14.6 (HER), respectively. The current density taken from long‐term OER measurements in pH 7 buffer solution upon the electro‐activated steel at 491 mV overpotential (η) is around four times higher (4 mA cm−2) in comparison with recently developed OER electrocatalysts. The very strong voltage–current behavior of the catalyst shown in OER polarization experiments at both pH 7 and at pH 13 are even superior to those known for IrO2‐RuO2. No degradation of the catalyst is detected even when conditions close to standard industrial operations are applied to the catalyst. A stable Ni‐, Fe‐oxide based passivating layer sufficiently protects the bare metal for further oxidation. Quantitative charge to oxygen (OER) and charge to hydrogen (HER) conversion are confirmed. High‐resolution XPS spectra show that most likely γ−NiO(OH) and FeO(OH) are the catalytic active OER and NiO is the catalytic active HER species. Harsh anodization has converted relatively less catalytically active untreated Ni42 steel into an outstanding bifunctional electrocatalyst (Ni42‐300). The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly efficiently and steadfast catalyzed at pH 7, 13, 14, 14.6 (OER) and at pH 0, 1, 13, 14, 14.6 (HER), respectively. Ni42‐300 can be utilized as electrodes in electrolyzers with bipolar cell configuration.
      PubDate: 2016-07-05T04:57:08.448673-05:
      DOI: 10.1002/adfm.201601581
       
  • Molybdenum Disulfide‐Based Tubular Microengines: Toward Biomedical
           Applications
    • Abstract: 2D molybdenum disulfide (MoS2) is herein explored as an advanced surface material in the fabrication of powerful tubular microengines. The new catalytic self‐propelled open‐tube bilayer microengines have been fabricated using a template electrodeposition and couple the unique properties of sp2 hybridized MoS2 with highly reactive inner granular Pt catalytic structures. The MoS2/metal microengines display extremely efficient bubble propulsion, reflecting the granular structure of the inner catalytic platinum or gold layers (compared to the smooth metal surfaces of common micromotors). The efficient movement of functionalized MoS2 micromotors can address challenges imposed by slow mass transport processes involved in various applications of MoS2. The delocalized electron network of the MoS2 outer layer facilitates π–π stacking interactions and endows the tubular microengines with a diverse array of capabilities. These are demonstrated here for efficient loading and release of the drug doxorubicin, and rapid and sensitive “OFF–ON” fluorescent detection of important nucleic acids (miRNA‐21) and proteins (thrombin) using microengines modified with dye‐labeled single‐stranded DNA and aptamer, respectively. Such coupling of the attractive capabilities of 2D‐MoS2 nanosheets with rapidly moving microengines provides an opportunity to develop multifunctional micromachines for diverse biomedical applications ranging from efficient drug delivery to the detection of important bioanalytes. Coupling of the attractive properties of MoS2 nanosheets with rapidly moving tubular microengines opens the door to multifunctional micromachines for diverse biomedical applications, ranging from biodetection of protein and nucleic acid biomarkers to drug delivery.
      PubDate: 2016-07-04T11:42:58.198709-05:
      DOI: 10.1002/adfm.201602005
       
  • Plasmonic‐Radiation‐Enhanced Metal Oxide Nanowire
           Heterojunctions for Controllable Multilevel Memory
    • Authors: Luchan Lin; Lei Liu, Kevin Musselman, Guisheng Zou, Walt W. Duley, Y. Norman Zhou
      Abstract: Nanowire memristor devices that display multilevel memory effects are of great interest for high‐density storage, however, numerous challenges remain in fabricating high‐quality, stable memory units. A plasmonic‐radiation‐enhanced technique is introduced in this work for scalably forming nanowire multilevel memory units with superior properties. Femtosecond laser irradiation of gold‐titanium dioxide nanowire‐gold structures results in plasmonic‐enhanced optical absorption in the TiO2 locally at the metal‐oxide interface. This produces junctions with superior mechanical and electrical contact, and engineers a concentration of charged defects in the TiO2 near the interface, which enables stable multilevel memory behavior without the need for a traditional electroforming step. The memory units produced display eight‐level current amplification under continuous forward voltage cycles, and can replicate complex multilevel memory sequences without interference between the different multilevel states. A fast and scalable method to modify metal‐oxide nanowire heterojunctions for nanowire memristor devices by using the localized plasmonic effects under optical excitation is presented. This engineered junction enables stable multilevel memory behavior for nanowire devices without the need for the traditional electroforming process.
      PubDate: 2016-07-04T11:21:27.932538-05:
      DOI: 10.1002/adfm.201601143
       
  • High‐Strength and High‐Toughness
           Double‐Cross‐Linked Cellulose Hydrogels: A New Strategy Using
           Sequential Chemical and Physical Cross‐Linking
    • Authors: Dan Zhao; Junchao Huang, Yi Zhong, Kai Li, Lina Zhang, Jie Cai
      Abstract: Polysaccharide‐based hydrogels have multiple advantages because of their inherent biocompatibility, biodegradability, and non‐toxicic properties. The feasibility of using polysaccharide‐based hydrogels could be improved if they could simultaneously fulfill the mechanical property and cell compatibility requirements for practical applications. Herein, the construction of double‐cross‐linked (DC) cellulose hydrogels is described using sequential chemical and physical cross‐linking, resulting in DC cellulose hydrogels that are mechanically superior to single‐cross‐linked cellulose hydrogels. The formation and spatial distribution of chemically cross‐linked domains and physically cross‐linked domains within the DC cellulose hydrogels are demonstrated. The molar ratio of epichlorohydrin to anhydroglucose units of cellulose and the concentration of the aqueous ethanol solution are two critical parameters for obtaining mechanically strong and tough DC cellulose hydrogels. The mechanical properties of the DC cellulose hydrogels under loading‐unloading cycles are described using compression and tension models. The possible toughening mechanism of double‐cross‐linking is discussed. Double‐cross‐linked (DC) cellulose hydrogels are fabricated by a sequential chemical and physical cross‐linking strategy. The irreversible covalent cross‐linkings, cellulose II crystallite hydrates, together with the chain entanglements and strong hydrogen bonding interactions between cellulose chains endow the DC cellulose hydrogels with high strength, high toughness, and good recoverability.
      PubDate: 2016-07-04T05:26:01.127957-05:
      DOI: 10.1002/adfm.201601645
       
  • Thermoelectric Properties of Polymeric Mixed Conductors
    • Authors: Ujwala Ail; Mohammad Javad Jafari, Hui Wang, Thomas Ederth, Magnus Berggren, Xavier Crispin
      Abstract: The thermoelectric (TE) phenomena are intensively explored by the scientific community due to the rather inefficient way energy resources are used with a large fraction of energy wasted in the form of heat. Among various materials, mixed ion‐electron conductors (MIEC) are recently being explored as potential thermoelectrics, primarily due to their low thermal conductivity. The combination of electronic and ionic charge carriers in those inorganic or organic materials leads to complex evolution of the thermovoltage (Voc) with time, temperature, and/or humidity. One of the most promising organic thermoelectric materials, poly(3,4‐ethyelenedioxythiophene)‐polystyrene sulfonate (PEDOT‐PSS), is an MIEC. A previous study reveals that at high humidity, PEDOT‐PSS undergoes an ionic Seebeck effect due to mobile protons. Yet, this phenomenon is not well understood. In this work, the time dependence of the Voc is studied and its behavior from the contribution of both charge carriers (holes and protons) is explained. The presence of a complex reorganization of the charge carriers promoting an internal electrochemical reaction within the polymer film is identified. Interestingly, it is demonstrated that the time dependence behavior of Voc is a way to distinguish between three classes of polymeric materials: electronic conductor, ionic conductor, and mixed ionic–electronic conductor. Monitoring the time dependence of the thermovoltage (Voc) is a way to distinguish between three classes of polymeric materials: electronic conductor, ionic conductor, and mixed electronic–ionic conductor. In case of a mixed ionic–electronic conductor, poly(3,4‐ethyelenedioxythiophene)‐polystyrene sulfonate (PEDOT‐PSS), electrical, and spectroscopic evidence show the presence of an internal electrochemical reaction induced within the conducting polymer layer promoted by the ionic thermoelectric effect.
      PubDate: 2016-07-04T05:25:32.417951-05:
      DOI: 10.1002/adfm.201601106
       
  • Morphological Tuning of the Energetics in Singlet Fission Organic Solar
           Cells
    • Authors: YunHui L. Lin; Michael A. Fusella, Oleg V. Kozlov, Xin Lin, Antoine Kahn, Maxim S. Pshenichnikov, Barry P. Rand
      Abstract: Effective singlet fission solar cells require both fast and efficient singlet fission as well as favorable energetics for harvesting the resulting triplet excitons. Notable progress has been made to engineer materials with rapid and efficient singlet fission, but the ability to control the energetics of these solar cells remains a challenge. Here, it is demonstrated that the interfacial charge transfer state energy of a rubrene/C60 solar cell can be modified dramatically by the morphology of its constituent films. The effect is so pronounced that a crystalline system is able to dissociate and collect triplets generated through singlet fission whereas an as‐deposited amorphous system is not. Furthermore, a novel technique for studying the behavior of this class of devices using external quantum efficiency (EQE) measurements in the presence of a background light is described. When this method is applied to rubrene/C60 solar cells, it is shown that triplet–triplet annihilation makes significant contributions to photocurrent in the amorphous device—enhancing EQE by over 12% at relatively low intensities of background light (4 mW cm−2)—while detracting from photocurrent in the crystalline device. Finally, the conclusions on how the material system is affected by its morphology are strengthened by time‐resolved photoluminescence experiments. The interfacial charge transfer state energy of a crystalline rubrene/C60 solar cell is over 300 meV lower than that of an amorphous rubrene/C60 device. Despite that both amorphous and crystalline rubrene undergo singlet fission, this shift means that only the crystalline device can dissociate the low energy triplets generated by singlet fission and operate as a singlet fission solar cell.
      PubDate: 2016-07-04T05:25:25.317714-05:
      DOI: 10.1002/adfm.201601125
       
  • Fabrication of a Targeted Drug Delivery System from a
           Pillar[5]arene‐Based Supramolecular Diblock Copolymeric Amphiphile
           for Effective Cancer Therapy
    • Authors: Guocan Yu; Wei Yu, Li Shao, Zhihua Zhang, Xiaodong Chi, Zhengwei Mao, Changyou Gao, Feihe Huang
      Abstract: Effective cancer therapy will profit from the development of sophisticated drug delivery systems with stimuli‐responsive properties that are capable of delivering therapeutic doses to the active sites, while minimizing the accumulation of highly toxic drugs in off‐target sites. Herein, the fabrication of a pillararene‐based amphiphilic supramolecular diblock polymer (P5‐PEG‐Biotin⊃PCL‐C2V) based on the host–guest recognition between a water‐soluble pillar[5]arene and a viologen salt is reported. P5‐PEG‐Biotin⊃PCL‐C2V self‐assembles into polymersomes, which are utilized as drug delivery vehicles for doxorubicin hydrochloride (DOX). Decorated by the biotin groups, these smart nanocarriers deliver the anticancer drug preferentially to biotin receptor over‐expressing cancer cells. After internalization by the cells, the viologen group is reduced into the cationic radical state by the intracellular reductase NAD(P)H, leading to the release of the loaded DOX by the disassembly of the polymersomes. More importantly, DOX‐loaded polymersomes maintain the therapeutic efficacy towards cancerous HeLa cells, while exhibiting relatively low cytotoxicity towards normal HEK293 cells. In vivo studies reveal that the DOX‐loaded supramolecular polymersomes prolong the circulation time in the bloodstream, promote the antitumor efficacy and reduce the systematic toxicity of the drug through flexible and modular supramolecular strategy. A reduction‐sensitive supramolecular diblock polymer is fabricated based on the molecular recognition motif between a novel water‐soluble pillar[5]arene and a viologen salt. It self‐assembles into polymersomes in water, which are successfully used in targeted drug delivery. In vitro and in vivo experiments demonstrate that these polymersomes can be applied in effective cancer treatment.
      PubDate: 2016-07-04T05:25:12.528305-05:
      DOI: 10.1002/adfm.201601770
       
  • Skin‐Like Oxide Thin‐Film Transistors for Transparent Displays
    • Abstract: Flexible transparent display is a promising candidate to visually communicate with each other in the future Internet of Things era. The flexible oxide thin‐film transistors (TFTs) have attracted attention as a component for transparent display by its high performance and high transparency. The critical issue of flexible oxide TFTs for practical display applications, however, is the realization on transparent and flexible substrate without any damage and characteristic degradation. Here, the ultrathin, flexible, and transparent oxide TFTs for skin‐like displays are demonstrated on an ultrathin flexible substrate using an inorganic‐based laser liftoff process. In this way, skin‐like ultrathin oxide TFTs are conformally attached onto various fabrics and human skin surface without any structural damage. Ultrathin flexible transparent oxide TFTs show high optical transparency of 83% and mobility of 40 cm2 V−1 s−1. The skin‐like oxide TFTs show reliable performance under the electrical/optical stress tests and mechanical bending tests due to advanced device materials and systematic mechanical designs. Moreover, skin‐like oxide logic inverter circuits composed of n‐channel metal oxide semiconductor TFTs on ultrathin, transparent polyethylene terephthalate film have been realized. The ultrathin, flexible, and transparent oxide thin‐film transistors for skin‐like displays are demonstrated on an ultrathin flexible substrate using an inorganic based laser liftoff process. The transferred transistor arrays with high mobility of ≈40 cm2 V−1 s−1 adhere to both fabric and human skin and operate stably without significant degradation of their characteristics. Finally, skin‐like oxide logic inverters are successfully manipulated to verify the dynamic responses on an ultrathin plastic substrate.
      PubDate: 2016-07-04T05:22:54.352557-05:
      DOI: 10.1002/adfm.201601296
       
  • Proteoid Dynamers with Tunable Properties
    • Abstract: A range of doubly dynamic proteoid biodynamers based on the polycondensation of various categories of amino acid hydrazides with a di‐ aldehyde have been generated through formation of two types of reversible CN bonds (imine and acylhydrazone). Their structures and properties (rates of polymerization and dynamic character) have been characterized by NMR, small‐angle neutron scattering, dynamic light scattering, and cryo‐transmission‐electron microscopy. Three types of structures (nanorods, globular nano‐objects, oligomers) are obtained at different rates after polycondensation. Competitive polymerization shows that electrostatic effects markedly influence polymerizations when two oppositely charged monomers are used, and an exchange experiment demonstrates the preferential incorporation of a specific monomer in the biodynamer chain. Taken together, all our results show that the side chains of the amino acid hydrazides have a strong influence on the rates of polymerization, structures, and dynamic properties of the resulting biodynamers. The present study provides a basis for the rational design and synthesis of various types of well‐ordered structures and adaptive materials, offering great potential for utilization in the field of biomaterials science. Doubly dynamic proteoids based on the polycondensation of amino acid hydrazides with dialdehyde have been generated through formation of imine and acylhydrazone bonds. The polymerization is driven by the enhanced stability of biodynamers resulting from folding of the main chain through hydrophobic and π–π‐stacking interactions. The structures of the polymers formed depend on the side chains of the corresponding amino acid hydrazides.
      PubDate: 2016-07-04T05:22:14.386821-05:
      DOI: 10.1002/adfm.201601612
       
  • Multistability in Bistable Ferroelectric Materials toward Adaptive
           Applications
    • Authors: Anirban Ghosh; Gertjan Koster, Guus Rijnders
      Abstract: Traditionally thermodynamically bistable ferroic materials are used for nonvolatile operations based on logic gates (e.g., in the form of field effect transistors). But, this inherent bistability in these class of materials limits their applicability for adaptive operations. Emulating biological synapses in real materials necessitates gradual tuning of resistance in a nonvolatile manner. Even though in recent years few observations have been made of adaptive devices using a ferroelectric, the principal question as to how to make a ferroelectric adaptive has remained elusive in the literature. Here, it is shown that by locally controlling the nucleation energy distribution at the ferroelectric–electrode interface multiple‐addressable states in a ferroelectric can be created, which is necessary for adaptive/synaptic applications. This is realized by depositing a layer of nonswitchable ZnO on top of thin film ferroelectric PbZr x Ti(1– x )O3. This methodology of interface‐engineered ferroelectric should enable realising brain‐like adaptive/synaptic memory in complementary metal‐oxide‐semiconductor (CMOS) devices. Furthermore, the temporally stable multistability in ferroelectrics should enable the designing of multistate memory and logic devices. Modification of the ferroelectric switching of PZT thin films is shown to depend on the thickness of a ZnO overlayer. Modifying the ratio of the roughness to the total thickness of ZnO gives rise to different adaptive behavior.
      PubDate: 2016-07-04T04:01:21.818144-05:
      DOI: 10.1002/adfm.201601353
       
  • Flexible Textile Strain Wireless Sensor Functionalized with Hybrid Carbon
           Nanomaterials Supported ZnO Nanowires with Controlled Aspect Ratio
    • Abstract: Smart fabrics and interactive textiles have attracted great interest as a newly emergent material because of their multifunctional capabilities. Herein, a highly robust wireless flexible strain sensor on the basis of commercial textile by the integration of functional hybrid carbon nanomaterials and piezoresistive material is fabricated. Specifically, a solution‐processable spray‐assisted coating approach that enables the creation of a uniform coating over a large area of fabrics is employed. The textile‐based strain sensor exhibits a highly stable and immediate response over a wide range of bending curvatures and structural properties of ZnO nanowires because of their different deflection behaviors. The wearing performance with attaching on commercial fabrics is further demonstrated. The as‐prepared sensor responds well to diverse body motions with accurate detection of strain magnitude and even extends its viability in wireless remote sensing by connecting to a wireless transmitter. The novel approach for the modification of textiles with functional nanomaterials may provide a feasible approach for the production of textile‐based electronics without employing any sophisticated fabrication processes, and it further exploits the diverse functionalities by utilizing various sensing components. A highly robust flexible strain sensor is fabricated through a facile integration of functional nanomaterials into a textile platform. It well demonstrates not only a rapid response to diverse body motions but also different strain sensing behaviors depending on geometrical features of ZnO nanostructure. Furthermore, the capability of the textile‐based sensor is extended to remote monitoring by configuration with wireless transmitter.
      PubDate: 2016-07-01T05:42:10.240224-05:
      DOI: 10.1002/adfm.201601237
       
  • “Suction Caps”: Designing Anisotropic Core/Shell Microcapsules
           with Controlled Membrane Mechanics and Substrate Affinity
    • Abstract: Core/shell microcapsules with low‐permeability membranes and controlled morphology are crucial for the delivery and controlled release of fragrance molecules, pharmaceuticals, inks, or vitamins. Design criteria for next generation microcapsules must include chemical and mechanical stability, and also provide enhanced substrate interactions to improve deposition onto relevant complex surfaces. Here, a coupled approach is presented to synthesize core/shell delivery systems by interfacial polymerization to enhance both the microcapsule–substrate interactions and the mechanical properties of the capsules to induce a burst‐type release. By combining membrane synthesis, nonlinear mechanics, interfacial rheology, analysis of mass transfer, and capsule morphology generated during interfacial polymerization, large permanent deformations into the capsule geometry are programmed, resulting in chemically stable, yet mechanically rupturing microcapsules with anisotropic geometry. To promote interactions and capsule adhesion onto complex substrates, the capsule contact area is controlled to form prominent “suction cup” shaped rims. These capsules have favorable, far‐reaching electrostatic interactions with oppositely charged substrates such as glass, hair, skin, or fabric. By modulating membrane mechanical properties and morphology during synthesis, formulation‐independent physical criteria are used to improve the overall performance of a functional delivery system while expanding knowledge of the key parameters influencing the interfacial polymerization process and membrane formation. Anisotropic core/shell microcapsules with “suction cup” morphologies provide enhanced affinity on complex substrates, such as the surface of human hair. The mechanics and permeability of the capsule membrane can be designed to synthesize chemically stable, yet mechanically rupturing targeted delivery systems for low‐molecular‐weight payloads.
      PubDate: 2016-07-01T05:42:03.330292-05:
      DOI: 10.1002/adfm.201601563
       
  • Highly Selective Ionic Transport through Subnanometer Pores in Polymer
           Films
    • Authors: Qi Wen; Dongxiao Yan, Feng Liu, Mao Wang, Yun Ling, Pengfei Wang, Patrick Kluth, Daniel Schauries, Christina Trautmann, Pavel Apel, Wei Guo, Guoqing Xiao, Jie Liu, Jianming Xue, Yugang Wang
      Abstract: Novel transport phenomena through nanopores are expected to emerge as their diameters approach subnanometer scales. However, it has been challenging to explore such a regime experimentally. Here, this study reports on polymer subnanometer pores exhibiting unique selective ionic transport. 12 μm long, parallel oriented polymer nanopores are fabricated in polyethylene terephthalate (PET) films by irradiation with GeV heavy ions and subsequent 3 h exposure to UV radiation. These nanopores show ionic transport selectivity spanning more than 6 orders of magnitude: the order of the transport rate is Li+>Na+>K+>Cs+>>Mg2+>Ca2+>Ba2+, and heavy metal ions such as Cd2+ and anions are blocked. The transport can be switched off with a sharp transition by decreasing the pH value of the electrolyte. Structural measurements and molecular dynamics simulations suggest that the ionic transport is attributed to negatively charged nanopores with pore radii of ≈0.3 nm, and the selectivity is associated with the dehydration effect. Negatively charged subnanometer pores are fabricated in polymer films by GeV heavy ions irradiation without chemical etching. Their selective ionic transport rates span more than 6 orders of magnitude and follow the rarely observed Eisenman sequence XI.
      PubDate: 2016-07-01T05:41:57.727144-05:
      DOI: 10.1002/adfm.201601689
       
  • High‐Quality Whispering‐Gallery‐Mode Lasing from Cesium
           Lead Halide Perovskite Nanoplatelets
    • Authors: Qing Zhang; Rui Su, Xinfeng Liu, Jun Xing, Tze Chien Sum, Qihua Xiong
      Abstract: Semiconductor micro/nano‐cavities with high quality factor (Q) and small modal volume provide critical platforms for exploring strong light‐matter interactions and quantum optics, enabling further development of coherent and quantum photonic devices. Constrained by exciton binding energy and thermal fluctuation, only a handful of wide‐band semiconductors such as ZnO and GaN have stable excitons at room temperature. Metal halide perovskite with cubic lattice and well‐controlled exciton may provide solutions. In this work, high‐quality single‐crystalline cesium lead halide CsPbX3 (X = Cl, Br, I) whispering‐gallery‐mode (WGM) microcavities are synthesized by vapor‐phase van der Waals epitaxy method. The as‐grown perovskites show strong emission and stable exciton at room temperature over the whole visible spectra range. By varying the halide composition, multi‐color (400–700 nm).WGM excitonic lasing is achieved at room temperature with low threshold (~ 2.0 μJ cm−2) and high spectra coherence (~0.14–0.15 nm). The results advocate the promise of inorganic perovskites towards development of optoelectronic devices and strong light‐matter coupling in quantum optics. High‐quality cesium lead halide nanoplatelets functioning as whispering‐gallery‐mode microcavities are synthesized by vapor‐phase van der Waals epitaxy method. Multicolor, low‐threshold excitonic lasing action with a high spectra coherence of 0.14–0.15 nm is realized at room temperature. The findings are not only important for developing on‐chip small lasers and high‐speed exciton devices but also promising for fundamental studies in cavity quantum electrodynamics.
      PubDate: 2016-07-01T05:41:53.65207-05:0
      DOI: 10.1002/adfm.201601690
       
  • Plasmon‐Induced Sub‐Bandgap Photodetection with Organic
           Schottky Diodes
    • Abstract: Organic materials for near‐infrared (NIR) photodetection are in the focus for developing organic optical‐sensing devices. The choice of materials for bulk‐type organic photodetectors is limited due to effects like high nonradiative recombination rates for low‐gap materials. Here, an organic Schottky barrier photodetector with an integrated plasmonic nanohole electrode is proposed, enabling structure‐dependent, sub‐bandgap photodetection in the NIR. Photons are detected via internal photoemission (IPE) process over a metal/organic semiconductor Schottky barrier. The efficiency of IPE is improved by exciting localized surface plasmon resonances, which are further enhanced by coupling to an out‐of‐plane Fabry–Pérot cavity within the metal/organic/metal device configuration. The device allows large on/off ratio (>1000) and the selective control of individual pixels by modulating the Schottky barrier height. The concept opens up new design and application possibilities for organic NIR photodetectors. An organic Schottky photodetector is combined with a plasmonic nanohole electrode to enable sub‐bandgap photodetection in the NIR. The responsivity can be modulated by an external field affecting the injection barrier for charge carriers from metal to organic. This allows >1000 on/off ratio and the selective control of individual pixel in detector matrix/arrays. The concept opens up new possibilities for organic optical‐sensing devices.
      PubDate: 2016-07-01T05:41:50.119935-05:
      DOI: 10.1002/adfm.201601718
       
  • Mo Doping Induced More Active Sites in Urchin‐Like W18O49
           Nanostructure with Remarkably Enhanced Performance for Hydrogen Evolution
           Reaction
    • Abstract: Exploring highly efficient and inexpensive hydrogen evolution reaction (HER) electrocatalysts for various electrochemical energy conversion technologies is actively encouraged. Herein, a 3D urchin‐like Mo‐W18O49 nanostructure as an efficient HER catalyst is reported for the first time. The obtained Mo‐W18O49 catalyst exhibits excellent electrocatalytic activity toward HER with small onset potential and Tafel slope. The prepared Mo‐W18O49 electrode shows excellent durability after a long period. Density functional theory calculations reveal that the remarkably enhanced performance of Mo‐W18O49 can be due to the ability of Mo dopant to increase the number of active sites, leading to optimal hydrogen adsorption on the active sites because of the electronic and geometric modulation. In addition, the urchin‐like 3D morphology with a high surface area and abundant 1D nanowires promotes electron transfer, thereby ensuring fast interfacial charge transfer to improve electrocatalytic reactions. All these experimental and theoretical results clearly reveal that Mo‐W18O49 intrinsically improves HER activity and thus has potential applications in water splitting. The 3D urchin‐like Mo‐W18O49 catalyst exhibits excellent electrocatalytic activity toward HER with small onset potential and Tafel slope, as well as excellent durability. The remarkably enhanced performance of Mo‐W18O49 can be ascribed to the synergistic effect of an increased amount of active sites and of activity improvment by Mo dopant, furthermore abundant agminated 1D nanowires also provide a high surface area.
      PubDate: 2016-07-01T05:41:46.147001-05:
      DOI: 10.1002/adfm.201601732
       
  • High‐Performance All‐Polymer Photoresponse Devices Based on
           Acceptor–Acceptor Conjugated Polymers
    • Authors: Xiaofen Wang; Lei Lv, Lingliang Li, Yusheng Chen, Kai Zhang, Haoran Chen, Huanli Dong, Jinsong Huang, Guozhen Shen, Zhou Yang, Hui Huang
      Abstract: Three acceptor–acceptor (A–A) type conjugated polymers based on isoindigo and naphthalene diimide/perylene diimide are designed and synthesized to study the effects of building blocks and alkyl chains on the polymer properties and performance of all‐polymer photoresponse devices. Variation of the building blocks and alkyl chains can influence the thermal, optical, and electrochemical properties of the polymers, as indicated by thermogravimetric analysis, differential scanning calorimetry, UV–vis, cyclic voltammetry, and density functional theory calculations. Based on the A–A type conjugated polymers, the most efficient all‐polymer photovoltaic cells are achieved with an efficiency of 2.68%, and the first all‐polymer photodetectors are constructed with high responsivity (0.12 A W−1) and detectivity (1.2 × 1012 Jones), comparable to those of the best fullerene based organic photodetectors and inorganic photodetectors. Photoluminescence spectra, charge transport properties, and morphology of blend films are investigated to elucidate the influence of polymeric structures on device performances. This contribution demonstrates a strategy of systematically tuning the polymeric structures to achieve high performance all‐polymer photoresponse devices. Three n‐type conjugated polymers are synthesized to achieve the most efficient acceptor–acceptor type polymer‐based all‐polymer photovoltaic cells with an efficiency of 2.68% and the first all‐polymer photodetectors with high responsivity (0.12 A W−1) and detectivity (1.2 × 1012 Jones). This contribution provides a strategy of tuning the polymeric structures to achieve high performance all‐polymer photoresponse devices.
      PubDate: 2016-07-01T05:41:41.689286-05:
      DOI: 10.1002/adfm.201601745
       
  • Dissociated and Reconstituted Cartilage Microparticles in Densified
           Collagen Induce Local hMSC Differentiation
    • Abstract: Current use of decellularized articular cartilage as a regenerative platform suffers from limited implant diffusion characteristics and cellular infiltration. Attempts to address this concern using decellularized cartilage microparticles allow for customized implant shape, tailored porosity, and improved cell infiltration. However, these developments utilize severe crosslinking agents that adversely affect cell differentiation, and fail to attain clinically relevant mechanical properties required for the implant survival. These issues have been overcome through the formation of a composite approach, combining the advantages of mature, decellularized tissue with tunable features of a reconstituted collagen hydrogel system. Through the application of a plastic compression regime, cellularized composite structures are formed that exceeded the percolation threshold of the cartilage microparticles and exhibited clinically relevant mechanical properties. Chemical reduction and mechanical reconstitution methods to investigate the contributions of glycosaminoglycan and collagenous components to chondrogenic induction and matrix properties have been utilized. With the inclusion of human mesenchymal stem cells into the composite system, microenvironment‐dependent cell morphology and phenotype when in contact with cartilage microparticles are shown. This work demonstrates a cartilage microparticle composite matrix with clinically relevant mechanical properties, and chondrogenic differentiation of human mesenchymal stem that infiltrate both native and chemically reduced cartilage microparticles. Decellularized cartilage microparticles, and all associated native signals, are delivered to human mesenchymal stem cell (hMSC) populations in a dense, type I collagen matrix. Hybrid usage of native tissue signals and the engineering control of collagen matrices show the ability to induce local infiltration and differentiation of hMSCs. Additionally, the solid cartilage microparticles inhibit bulk cell‐mediated contraction of the composite.
      PubDate: 2016-07-01T05:41:36.815954-05:
      DOI: 10.1002/adfm.201601877
       
  • Carbon Fiber Reinforced Thermoset Composite with Near 100% Recyclability
    • Authors: Kai Yu; Qian Shi, Martin L. Dunn, Tiejun Wang, H. Jerry Qi
      Abstract: Both environmental and economic factors have driven the development of recycling routes for the increasing amount of composite waste generated. This paper presents a new paradigm to fully recycle epoxy‐based carbon fiber reinforced polymer (CFRP) composites. After immersing the composite in ethylene glycol (EG) and increasing the temperature, the epoxy matrix can be dissolved as the EG molecules participate in bond exchange reactions (BERs) within the covalent adaptable network (CAN), effectively breaking the long polymer chains into small segments. The clean carbon fibers can be then reclaimed with the same dimensions and mechanical properties as those of fresh ones. Both the dissolution rate and the minimum amount of EG required to fully dissolve the CAN are experimentally determined. Further heating the dissolved solution leads to repolymerization of the epoxy matrix, so a new generation of composite can be fabricated by using the recycled fiber and epoxy; in this way a closed‐loop near 100% recycling paradigm is realized. In addition, epoxy composites with surface damage are shown to be fully repaired. Both the recycled and the repaired composites exhibit the same level of mechanical properties as fresh materials. A new method to fully recycle the carbon fiber reinforced thermoset composites is developed. After immersing the composite in solvent, the polymer matrix can be dissolved and clean carbon fibers are reclaimed; both, matrix material and carbon fibres, can be recycled and reused for the same purpose. The developed method can also be used to repair composite with surface damage.
      PubDate: 2016-07-01T05:41:32.868407-05:
      DOI: 10.1002/adfm.201602056
       
  • A Red Light Activatable Multifunctional Prodrug for Image‐Guided
           Photodynamic Therapy and Cascaded Chemotherapy
    • Abstract: A multifunctional prodrug, designated as TPP‐L‐GEM, is fabricated to realize image‐guided in situ tumor photodynamic therapy (PDT) with red light activatable chemotherapy. Gemcitabine is conjugated with a fluorescent photosensitizer, meso‐tetraphenylporphyrin (TPP), by a reactive oxygen species cleavable thioketal linker. Under the irradiation of low‐energy red light, TPP can generate singlet oxygen and damage tumor cells by photodynamic therapy. Simultaneously, the thioketal linkage can be cleaved by singlet oxygen and result in a cascaded gemcitabine release, causing sustained cell damage by chemotherapy. With the combination of PDT and cascaded chemotherapy, TPP‐L‐GEM shows significant tumor therapeutic efficacy in vitro and in vivo. Furthermore, the inherent fluorescent property of TPP endows the TPP‐L‐GEM prodrug with noninvasive drug tracking capability, which is favorable for image‐guided tumor therapy. A red light activatable multifunctional prodrug is fabricated to realize in situ tumor photodynamic therapy (PDT) with cascaded chemotherapy. This multifunctional prodrug demonstrates a new strategy for image‐guided combination therapy of PDT with cascaded chemotherapy.
      PubDate: 2016-07-01T05:41:28.014962-05:
      DOI: 10.1002/adfm.201602541
       
  • Designer Colloidal Layers of Disordered Plasmonic Nanoparticles for Light
           Extraction
    • Authors: Anthony Jouanin; Jean Paul Hugonin, Philippe Lalanne
      Abstract: Basic design rules are disclosed for broadband light‐extraction colloidal films formed with disordered ensembles of plasmonic particles. They are derived through the numerical study of a test‐bed geometry consisting of a low‐refractive index slab in air. Albeit simple, the geometry encompasses many physically effects encountered in real light‐emitting devices, including the pronounced absorption at the peak of the nanoparticles resonance spectrum, the anisotropy of the radiation diagram of nanoparticles in waveguides and unavoidable coherent multiple interferences that ruin the predictive strength of first‐order scattering models. How we can simultaneously take advantage of (1) the shape or size of the individual nanoparticles, (2) their transverse position with respect to the guiding photonic structure, (3) their concentration, and (4) the structural topology of the disorder ensemble are illustrated. Following this approach, a threefold enhancement in the extraction efficiency can be reached as compared to a film without plasmonic particles. It is also predicted that the extraction rapidly saturates and then decreases as the nanoparticle density increases, suggesting that best performance is achieved at low concentrations. Spectrally broad and directionally random far‐field radiation diagrams are additionally reported, which do not suffer from deterministic interferential behaviors observed at particular wavelengths and directionalities with periodic light‐extraction structures. With advanced electromagnetic‐computation tools, the optical properties of colloidal add‐layers composed of random arrays of hundreds of metallic nanoparticles and proposed general guidelines on how to engineer nanoparticle shape and disorder structural topology to maximize the extraction efficiency are studied.
      PubDate: 2016-06-30T11:05:58.320256-05:
      DOI: 10.1002/adfm.201600730
       
  • Fullerene Adducts Bearing Cyano Moiety for Both High Dielectric Constant
           and Good Active Layer Morphology of Organic Photovoltaics
    • Authors: Sheng Zhang; Zijian Zhang, Jun Liu, Lixiang Wang
      Abstract: Power conversion efficiency (PCE) of organic photovoltaics (OPVs) lags behind of inorganic photovoltaics due to low dielectric constants (ε r) of organic semiconductors. Although OPVs with high ε r are attractive in theory, practical demonstration of efficient OPV devices with high‐ε r materials is in its infancy. This is largely due to the contradiction between the requirements of high ε r and good donor:acceptor blend morphology in the bulk heterojunction. Herein, a series of fullerene acceptors is reported bearing a polar cyano moiety for both high ε r and good donor:acceptor blend morphology. These cyano‐functionalized acceptors (ε r = 4.9) have higher ε r than that of the widely used acceptor, [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) (ε r = 3.9). The high ε r is realized without decrease of electron mobility and change of the lowest unoccupied molecular orbital/highest occupied molecular orbital (LUMO/HOMO) energy levels. Although the cyano‐functionalized acceptors have increased polarity, they still exhibit good compatibility with the typical donor polymer. Polymer solar cells based on the cyano‐functionalized acceptors exhibit good active layer morphology and show better device performance (PCE = 5.55%) than that of PC61BM (PCE = 4.56%). Fullerene adducts bearing a cyano moiety with large dipole moment show not only a high dielectric constant, but also good compatibility with the donor polymer for good blend morphology, and exhibit good polymer solar cell device performances.
      PubDate: 2016-06-29T10:26:16.825728-05:
      DOI: 10.1002/adfm.201600350
       
  • General Synthesis of Transition Metal Oxide Ultrafine Nanoparticles
           Embedded in Hierarchically Porous Carbon Nanofibers as Advanced Electrodes
           for Lithium Storage
    • Authors: Guanglin Xia; Lijun Zhang, Fang Fang, Dalin Sun, Zaiping Guo, Huakun Liu, Xuebin Yu
      Abstract: A unique general, large‐scale, simple, and cost‐effective strategy, i.e., foaming‐assisted electrospinning, for fabricating various transition metal oxides into ultrafine nanoparticles (TMOs UNPs) that are uniformly embedded in hierarchically porous carbon nanofibers (HPCNFs) has been developed. Taking advantage of the strong repulsive forces of metal azides as the pore generator during carbonization, the formation of uniform TMOs UNPs with homogeneous distribution and HPCNFs is simultaneously implemented. The combination of uniform ultrasmall TMOs UNPs with homogeneous distribution and hierarchically porous carbon nanofibers with interconnected nanostructure can effectively avoid the aggregation, dissolution, and pulverization of TMOs, promote the rapid 3D transport of both Li ions and electrons throughout the whole electrode, and enhance the electrical conductivity and structural integrity of the electrode. As a result, when evaluated as binder‐free anode materials in Li‐ion batteries, they displayed extraordinary electrochemical properties with outstanding reversible capacity, excellent capacity retention, high Coulombic efficiency, good rate capability, and superior cycling performance at high rates. More importantly, the present work opens up a wide horizon for the fabrication of a wide range of ultrasmall metal/metal oxides distributed in 1D porous carbon structures, leading to advanced performance and enabling their great potential for promising large‐scale applications. A general, large‐scale, and cost‐effective strategy is demonstrated toward fabricating transition metal oxides into ultrafine nanoparticles (TMOs) uniformly embedded in porous carbon nanofibers. Such unique nanostructures efficiently avoid the aggregation and pulverization of TMOs, promote the transport of both Li ions and electrons, and enhance the electrical conductivity and structural integrity, leading to significantly improved lithium storage performance.
      PubDate: 2016-06-29T10:26:13.280018-05:
      DOI: 10.1002/adfm.201601685
       
  • Large‐Area Compliant, Low‐Cost, and Versatile
           Pressure‐Sensing Platform Based on Microcrack‐Designed Carbon
           Black@Polyurethane Sponge for Human–Machine Interfacing
    • Authors: Xiaodong Wu; Yangyang Han, Xinxing Zhang, Zehang Zhou, Canhui Lu
      Abstract: It is a challenge to manufacture pressure‐sensing materials that possess flexibility, high sensitivity, large‐area compliance, and capability to detect both tiny and large motions for the development of artificial intelligence products. Herein, a very simple and low‐cost approach is proposed to fabricate versatile pressure sensors based on microcrack‐designed carbon black (CB)@polyurethane (PU) sponges via natural polymer‐mediated water‐based layer‐by‐layer assembly. These sensors are capable of satisfying the requirements of ultrasmall as well as large motion monitoring. The versatility of these sensors benefits from two aspects: microcrack junction sensing mechanism for tiny motion detecting (91 Pa pressure, 0.2% strain) inspired by the spider sensory system and compressive contact of CB@PU conductive backbones for large motion monitoring (16.4 kPa pressure, 60% strain). Furthermore, these sensors exhibit excellent flexibility, fast response times (
      PubDate: 2016-06-29T10:25:47.070253-05:
      DOI: 10.1002/adfm.201601995
       
  • 3D Carbonaceous Current Collectors: The Origin of Enhanced Cycling
           Stability for High‐Sulfur‐Loading Lithium–Sulfur
           Batteries
    • Abstract: The cycling stability of high‐sulfur‐loading lithium–sulfur (Li–S) batteries remains a great challenge owing to the exaggerated shuttle problem and interface instability. Despite enormous efforts on design of advanced electrodes and electrolytes, the stability issue raised from current collectors has been rarely concerned. This study demonstrates that rationally designing a 3D carbonaceous macroporous current collector is an efficient and effective “two‐in‐one” strategy to improve the cycling stability of high‐sulfur‐loading Li–S batteries, which is highly versatile to enable various composite cathodes with sulfur loading >3.7 mAh cm−2. The best cycling performance can be achieved upon 950 cycles with a very low decay rate of 0.029%. Moreover, the origin of such a huge enhancement in cycling stability is ascribed to (1) the inhibition of electrochemical corrosion, which severely occurs on the typical Al foil and disables its long‐term sustainability for charge transfer, and (2) the passivation of cathode surface. The role of the chemical resistivity against corrosion and favorable macroscopic porous structure is highlighted for exploiting novel current collectors toward exceptional cycling stability of high‐sulfur‐loading Li–S batteries. A 3D carbonaceous current collector assembled from millimeter‐long carbon nanotubes (CNTs) significantly enhances the cycling stability of lithium–sulfur batteries with high sulfur loading >3.7 mg cm−2, of which the lowest capacity decay rate is 0.029% per cycle upon 950 cycles. The enhancement originates from the high chemical stability and intrinsic macroporous structure of CNTs compared to 2D Al and graphene current collectors.
      PubDate: 2016-06-29T10:25:39.016174-05:
      DOI: 10.1002/adfm.201602071
       
  • Superaerophobic Electrode with Metal@Metal‐Oxide Powder Catalyst for
           Oxygen Evolution Reaction
    • Authors: Jinling He; Binbin Hu, Yong Zhao
      Abstract: A stable and highly active oxygen evolution reaction (OER) electrode is the key for fast and robust O2 production, which is one of the essential points for various kinds of energy conversion systems, such as water splitting, lithium‐O2 battery and artificial photosynthesis. Here, superaerophobic electrodes with metal@metal‐oxide powder catalysts are shown, which demonstrate high and stable OER activity. The active‐site‐density of metal@metal‐oxide catalysts is increased over one order of magnitude than those of pure metal oxides due to the large enhancement of electrical conductivity, revealing the substantial enhancement of electrochemical OER kinetics. Furthermore, the superaerophobic property of electrodes is favorable for fast O2 desorption, which improves electrochemical active surface area (EASA) during OER. The superaerophobic electrode with metal@metal‐oxide powder catalysts provides the new insight for increase of active‐site‐density and EASA simultaneously, which are the key factors to determine the activity of OER electrode. A superaerophobic electrode assembled with metal@metal‐oxide powder catalyst shows dense active site and enhanced electrochemical active surface area, resulting in efficient oxygen evolution reactions activity.
      PubDate: 2016-06-29T10:25:31.666421-05:
      DOI: 10.1002/adfm.201602116
       
  • Tumor‐Microenvironment‐Adaptive Nanoparticles Codeliver
           Paclitaxel and siRNA to Inhibit Growth and Lung Metastasis of Breast
           Cancer
    • Authors: Shan Tang; Qingshuo Meng, Huiping Sun, Jinghan Su, Qi Yin, Zhiwen Zhang, Haijun Yu, Lingli Chen, Yi Chen, Wangwen Gu, Yaping Li
      Abstract: Prolonged circulation, specific and effective uptake by tumor cells, and rapid intracellular drug release are three main factors for the drug delivery systems to win the battle against metastatic breast cancer. In this work, a tumor microenvironment‐adaptive nanoparticle co‐loading paclitaxel (PTX) and the anti‐metastasis siRNA targeting Twist is prepared. The nanoparticle consists of a pH‐sensitive core, a cationic shell, and a matrix metalloproteinase (MMP)‐cleavable polyethylene glycol (PEG) corona conjugated via a peptide linker. PEG will be cut away by MMPs at the tumor site, which endows the nanoparticle with smaller particle size and higher positive charge, leading to more efficient cellular uptake in tumor cells and higher intra‐tumor accumulation of both PTX and siRNA in the 4T1 tumor‐bearing mice models compared to the nanoparticles with irremovable PEG. In addition, acid‐triggered drug release in endo/lysosomes is achieved through the pH‐sensitive core. As a result, the MMP/pH dual‐sensitive nanoparticles significantly inhibit tumor growth and pulmonary metastasis. Therefore, this tumor‐microenvironment‐adaptive nanoparticle can be a promising codelivery vector for effective therapy of metastatic breast cancer due to simultaneously satisfying the requirements of long circulating time, efficient tumor cell targeting, and fast intracellular drug release. A nanoparticle for codelivery of siRNA and paclitaxel, consisting of a pH‐sensitive core, a cationic shell, and a matrix metalloproteinase (MMP)‐cleavable polyethylene glycol (PEG) corona, is constructed for cancer therapy. Balancing of long blood circulation times, selective uptake by tumor cells, and rapid intracellular drug release is achieved.
      PubDate: 2016-06-27T11:07:30.342709-05:
      DOI: 10.1002/adfm.201601703
       
  • Infrared‐Emitting QDs for Thermal Therapy with Real‐Time
           Subcutaneous Temperature Feedback
    • Abstract: Nowadays, one of the most exciting applications of nanotechnology in biomedicine is the development of localized, noninvasive therapies for diverse diseases, such as cancer. Among them, nanoparticle‐based photothermal therapy (PTT), which destroys malignant cells by delivering heat upon optical excitation of nanoprobes injected into a living specimen, is emerging with great potential. Two main milestones that must be reached for PTT to become a viable clinical treatment are deep penetration of the triggering optical excitation and real‐time accurate temperature monitoring of the ongoing therapy, which constitutes a critical factor to minimize collateral damage. In this work, a yet unexplored capability of near‐infrared emitting semiconductor nanocrystals (quantum dots, QDs) is demonstrated. Temperature self‐monitored ­QD‐based PTT is presented for the first time using PbS/CdS/ZnS QDs emitting in the second biological window. These QDs are capable of acting, simultaneously, as photothermal agents (heaters) and high‐resolution fluorescent thermal sensors, making it possible to achieve full control over the intratumoral temperature increment during PTT. The differences observed between intratumoral and surface temperatures in this comprehensive investigation, through different irradiation conditions, highlight the need for real‐time control of the intratumoral temperature that allows for a dynamic adjustment of the treatment conditions in order to maximize the efficacy of the therapy. PbS/CdS/ZdS quantum dots (QDs) ­allow intratumoral temperature feedback in real time during photothermal therapy because of their temperature‐sensitive fluorescence emission in the second biological window and their remarkable photothermal conversion efficiency. ­Continuous monitoring of the intratumoral temperature, which differs greatly from that at the surface during the treatment, makes dynamic control of the therapy to maximize its efficacy possible.
      PubDate: 2016-06-27T11:07:00.266478-05:
      DOI: 10.1002/adfm.201601953
       
  • Understanding the Structural Evolution and Redox Mechanism of a
           NaFeO2–NaCoO2 Solid Solution for Sodium‐Ion Batteries
    • Authors: Kei Kubota; Takuya Asari, Hiroaki Yoshida, Naoaki Yaabuuchi, Hiromasa Shiiba, Masanobu Nakayama, Shinichi Komaba
      Abstract: Na‐ion batteries have become promising candidates for large‐scale energy‐storage systems because of the abundant Na resources and they have attracted considerable academic interest because of their unique behavior, such as their electrochemical activity for the Fe3+/Fe4+ redox couple. The high‐rate performance derived from the low Lewis‐acidity of the Na+ ions is another advantage of Na‐ion batteries and has been demonstrated in NaFe1/2Co1/2O2 solutions. Here, a solid solution of NaFeO2‐NaCoO2 is synthesized and the mechanisms behind their excellent electrochemical performance are studied in comparison to those of their respective end‐members. The combined analysis of operando X‐ray diffraction, ex situ X‐ray absorption spectroscopy, and density functional theory (DFT) calculations for Na1– x Fe1/2Co1/2O2 reveals that the O3‐type phase transforms into a P3‐type phase coupled with Na+/vacancy ordering, which has not been observed in O3‐type NaFeO2. The substitution of Co for Fe stabilizes the P3‐type phase formed by sodium extraction and could suppress the irreversible structural change that is usually observed in O3‐type NaFeO2, resulting in a better cycle retention and higher rate performance. Although no ordering of the transition metal ions is seen in the neutron diffraction experiments, as supported by Monte‐Carlo simulations, the formation of a superlattice originating from the Na+/vacancy ordering is found by synchrotron X‐ray diffraction for Na0.5Fe1/2Co1/2O2, which may involve a potential step in the charge/discharge profiles. To understand the origin of the excellent rate performance of NaFe1/2Co1/2O2 in Na batteries, the reaction mechanism is studied using operando X‐ray diffraction, ex situ X‐ray absorption spectroscopy, and density functional theory calculations. Na extraction induces the O3‐type NaFe1/2Co1/2O2 to transform into a P3‐type phase coupled with Na+/vacancy ordering. The wide capacity range for the P3‐type phase and the monophasic P3–O3 transition around the end of charge are key factors for high‐rate Na‐ion batteries.
      PubDate: 2016-06-23T11:20:47.152877-05:
      DOI: 10.1002/adfm.201601292
       
  • Anomalous Anisotropic Magnetoresistance of Antiferromagnetic Epitaxial
           Bimetallic Films: Mn2Au and Mn2Au/Fe Bilayers
    • Abstract: Recently intensive efforts have been devoted to the emerging field of antiferromagnetic (AFM) spintronics, where ferromagnetic electrodes are substituted by antiferromagnets. This study investigates the anisotropic magnetoresistance (AMR) of epitaxial tetragonal antiferromagnetic bimetallic films: Mn2Au and Mn2Au/Fe bilayers. An anomalous AMR effect with additional peaks is observed. This study theoretically and experimentally demonstrates that the AFM spins of Mn2Au can be viewed and controlled at room temperature, and this is achievable with a notably relatively small magnetic field of 200 mT. Strong hybridization between Au and Mn, and strong modification of the intrinsic quadratic anisotropy of Mn2Au from interfacial biquadratic anisotropy result in an additional anomalous AMR component of 1%. The findings suggest that Mn2Au films can be used in room temperature antiferromagnetic spintronics. Mn2Au, a bimetallic antiferromagnet, is considered an interesting high Néel temperature candidate within the emerging field of antiferromagnetic spintronic devices. An anomalous anisotropic magnetoresistance effect is observed with four peaks, persisting to room‐temperature for a field as low as 200 mT, demonstrating how Mn2Au spins can be viewed and controlled at room‐temperature and offering a route to room‐temperature antiferromagnetic spintronics.
      PubDate: 2016-06-22T11:21:28.962955-05:
      DOI: 10.1002/adfm.201601348
       
  • Improved Hydrogen Production of Au–Pt–CdS
           Hetero‐Nanostructures by Efficient Plasmon‐Induced
           Multipathway Electron Transfer
    • Abstract: The design of new functional materials with excellent hydrogen production activity under visible‐light irradiation has critical significance for solving the energy crisis. A well‐controlled synthesis strategy is developed to prepare an Au–Pt–CdS hetero‐nanostructure, in which each component of Au, Pt, and CdS has direct contact with the other two materials; Pt is on the tips and a CdS layer along the sides of an Au nanotriangle (NT), which exhibits excellent photocatalytic activity for hydrogen production under light irradiation (λ > 420 nm). The sequential growth and surfactant‐dependent deposition produce the three‐component Au–Pt–CdS hybrids with the Au NT acting as core while Pt and CdS serve as a co‐shell. Due to the presence of the Au NT cores, the Au–Pt–CdS nanostructures possess highly enhanced light‐harvesting and strong local‐electric‐field enhancement. Moreover, the intimate and multi‐interface contact generates multiple electron‐transfer pathways (Au to CdS, CdS to Pt and Au to Pt) which guide photoexcited electrons to the co‐catalyst Pt for an efficient hydrogen reduction reaction. By evaluating the hydrogen production rate when aqueous Na2SO3–Na2S solution is used as sacrificial agent, the Au–Pt–CdS hybrid exhibits excellent photocatalytic activity that is about 2.5 and 1.4 times larger than those of CdS/Pt and Au@CdS/Pt, respectively. A well‐controlled synthetic strategy is developed to selectively grow Pt nanoparticles on the tips of Au nanotriangles and coat a CdS layer along the sides. The as‐prepared Au–Pt–CdS hybrids combine a plasmon‐enhanced local field with visible to NIR light‐harvesting and an efficient multipathway electron transfer, resulting in excellent photocatalytic activity for hydrogen production.
      PubDate: 2016-06-22T11:21:15.44782-05:0
      DOI: 10.1002/adfm.201601651
       
  • Carbon Capture: Visible Light Triggered CO2 Liberation from Silver
           Nanocrystals Incorporated Metal–Organic Frameworks (Adv. Funct.
           Mater. 27/2016)
    • Authors: Haiqing Li; Matthew R. Hill, Christian Doblin, Seng Lim, Anita J. Hill, Paolo Falcaro
      Pages: 4805 - 4805
      Abstract: H. Li, P. Falcaro, and coworkers describe on page 4815 the development of a new photodynamic Metal‐Organic Framework (MOF) composite that exhibits up to 90.5% of CO2 desorption capacity under the irradiation of naturally abundant visible light. Their discovery is promising for the application of MOFs in carbon capture as a route to low‐energy regeneration of gas adsorbents.
      PubDate: 2016-07-19T01:10:15.901205-05:
      DOI: 10.1002/adfm.201670169
       
  • Organic Solar Cells: Multi‐Length Scaled Silver Nanowire Grid for
           
    • Authors: Jiang Wu; Xinglu Que, Qin Hu, Deying Luo, Tanghao Liu, Feng Liu, Thomas P. Russell, Rui Zhu, Qihuang Gong
      Pages: 4806 - 4806
      Abstract: T. P. Russell, R. Zhu, and co‐workers present on page 4822 the patterning of silver nanowire transparent electrode by a neutral vapor etching process. Multi‐length‐scaled silver nanowire grids are demonstrated as the transparent conducting electrodes for polymer solar cells. Improved optical transmittance and enhanced usage of incident photons are achieved.
      PubDate: 2016-07-19T01:10:22.053793-05:
      DOI: 10.1002/adfm.201670170
       
  • Contents: (Adv. Funct. Mater. 27/2016)
    • Pages: 4807 - 4814
      PubDate: 2016-07-19T01:10:19.630845-05:
      DOI: 10.1002/adfm.201670171
       
  • Visible Light Triggered CO2 Liberation from Silver Nanocrystals
           Incorporated Metal–Organic Frameworks
    • Authors: Haiqing Li; Matthew R. Hill, Christian Doblin, Seng Lim, Anita J. Hill, Paolo Falcaro
      Pages: 4815 - 4821
      Abstract: Widespread deployment of metal–organic frameworks (MOFs) for CO2 capture remains challenging due to the great energy‐penalty associated with their regeneration. To overcome this challenge, a new type of photodynamic carbon capture material synthesized by incorporating Ag nanocrystals with UiO‐66 (Ag/UiO‐66) framework is presented. Upon the irradiation of visible light, Ag nanocrystals within the composites serve as “nanoheaters” to convert photon energy into thermal energy locally. Driven by such light‐induced localized heat (LLH), the adsorbed CO2 within MOFs is remotely released. The CO2 desorption capacity of such Ag/UiO‐66 composites can be readily regulated by control over their Ag contents and the applied light intensity. Up to 90.5% of CO2 desorption is achieved under the investigated conditions. Distinct from the traditional light‐responsive MOFs for gas trigger release, currently developed LLH‐driven CO2 release method not only offers a promising solution to the heat‐insulating nature of MOFs, but also demonstrates a potentially low energy method to remotely regenerate MOF adsorbents given the utilization of naturally abundant visible light as efficient stimulus. A new type of photodynamic carbon capture material with up to 90.5% of CO2 desorption capacity is synthesized via integration of silver nanocrystals with UiO‐66 metal–organic frameworks. Such a highly efficient CO2 desorption is driven by the naturally abundant visible light, confirming a promising alternative to low energy regeneration of gas adsorbents.
      PubDate: 2016-05-23T11:22:34.952696-05:
      DOI: 10.1002/adfm.201600827
       
  • Multi‐Length Scaled Silver Nanowire Grid for Application in
           Efficient Organic Solar Cells
    • Authors: Jiang Wu; Xinglu Que, Qin Hu, Deying Luo, Tanghao Liu, Feng Liu, Thomas P. Russell, Rui Zhu, Qihuang Gong
      Pages: 4822 - 4828
      Abstract: Transparent conducting electrodes (TCEs) with multi‐length scaled structure are promising candidates as a potential replacement for indium tin oxide (ITO). In this work, multi‐length scaled silver nanowire (AgNW) grids are demonstrated as TCEs for organic solar cells. The multi‐length scale silver nanowire grids are prepared by top‐down patterning using a neutral vapor etching process. Patterning AgNW film into multi‐length scale grid structures could improve the optical transmittance and enhance the use of incident photons. Based on these multi‐length scale AgNW grids, inverted bulk heterojunction polymer solar cells with power conversion efficiency up to 9.02% are fabricated, which are higher than that based on the original AgNW films and comparable to that based on ITO. Multi‐length scaled silver nanowire (AgNW) grids are prepared as transparent conducting electrodes through a neutral vapor etching process. Organic solar cells with power conversion efficiency up to 9.02% are fabricated based on the multi‐length scaled AgNW grids, which is higher than that based on original AgNW films and comparable to that based on indium tin oxide.
      PubDate: 2016-05-27T05:51:47.400093-05:
      DOI: 10.1002/adfm.201601049
       
  • Nanopore Sequencing: Graphene Nanopores for Protein Sequencing (Adv.
           Funct. Mater. 27/2016)
    • Authors: James Wilson; Leila Sloman, Zhiren He, Aleksei Aksimentiev
      Pages: 4829 - 4829
      Abstract: In nanopore sequencing of proteins, the amino acid sequence is determined by measuring the ionic current through a nanopore in a thin membrane as the protein chain permeates through the nanopore. The computational study by A. Aksimentiev and co‐workers, presented on page 4830, explores the feasibility of using nanopores in graphene for protein sequencing. The image illustrates the conformations of an unfolded protein threaded through a graphene nanopore.
      PubDate: 2016-07-19T01:10:19.239896-05:
      DOI: 10.1002/adfm.201670173
       
  • Graphene Nanopores for Protein Sequencing
    • Authors: James Wilson; Leila Sloman, Zhiren He, Aleksei Aksimentiev
      Pages: 4830 - 4838
      Abstract: An inexpensive, reliable method for protein sequencing is essential to unraveling the biological mechanisms governing cellular behavior and disease. Current protein sequencing methods suffer from limitations associated with the size of proteins that can be sequenced, the time, and the cost of the sequencing procedures. This study reports the results of all‐atom molecular dynamics simulations that investigated the feasibility of using graphene nanopores for protein sequencing. The study is focused on the biologically significant phenylalanine‐glycine repeat peptides (FG‐nups)—parts of the nuclear pore transport machinery. Surprisingly, FG‐nups are found to behave similarly to single stranded DNA: The peptides adhere to graphene and exhibit stepwise translocation when subject to a transmembrane bias or a hydrostatic pressure gradient. Reducing the peptide's charge density or increasing the peptide's hydrophobicity is found to decrease the translocation speed. Yet, unidirectional and stepwise translocation driven by a transmembrane bias is observed even when the ratio of charged to hydrophobic amino acids is as low as 1:8. The nanopore transport of the peptides is found to produce stepwise modulations of the nanopore ionic current correlated with the type of amino acids present in the nanopore, suggesting that protein sequencing by measuring ionic current blockades may be possible. Results of molecular dynamics simulations suggest that unfolded peptides can pass through a graphene nanopore in a stepwise manner when subject to a transmembrane bias or a hydrostatic pressure gradient. Such nanopore transport produces stepwise modulations of the nanopore ionic current correlated with the type of amino acids present in the nanopore.
      PubDate: 2016-06-09T13:24:02.294313-05:
      DOI: 10.1002/adfm.201601272
       
  • Overall Water Splitting Catalyzed Efficiently by an Ultrathin
           Nanosheet‐Built, Hollow Ni3S2‐Based Electrocatalyst
    • Pages: 4839 - 4847
      Abstract: Making highly efficient catalysts for an overall ​water splitting reaction is vitally important to bring solar/electrical‐to‐hydrogen energy conversion processes into reality. Herein, the synthesis of ultrathin nanosheet‐based, hollow MoOx/Ni3S2 composite microsphere catalysts on nickel foam, using ammonium molybdate as a precursor and the triblock copolymer pluronic P123 as a structure‐directing agent is reported. It is also shown that the resulting materials can serve as bifunctional, non‐noble metal electrocatalysts with high activity and stability for the hydrogen evolution reaction (HER) as well as the oxygen evolution reaction (OER). Thanks to their unique structural features, the materials give an impressive water‐splitting current density of 10 mA cm−2 at ≈1.45 V with remarkable durability for >100 h when used as catalysts both at the cathode and the anode sides of an alkaline electrolyzer. This performance for an overall water splitting reaction is better than even those obtained with an electrolyzer consisting of noble metal‐based Pt/C and IrOx/C catalytic couple—the benchmark catalysts for HER and OER, respectively. A novel, non‐noble metal‐based water splitting electrocatalyst comprising nickel foam‐supported, ultrathin nanosheet‐built, hollow MoOx/Ni3S2 microspheres has been synthesized. This material gives an impressive water‐splitting current density of 10 mA cm−2 at ≈1.45 V with remarkable durability for >100 h when used as electrocatalysts both at the cathode and the anode sides of an alkaline electrolyzer.
      PubDate: 2016-05-30T08:36:50.946669-05:
      DOI: 10.1002/adfm.201601315
       
  • Mechanoluminescence Color Conversion by Spontaneous
           Fluorescent‐Dye‐Diffusion in Elastomeric Zinc Sulfide
           Composite
    • Pages: 4848 - 4858
      Abstract: Color conversion, long‐wavelength light emission by absorbing short‐wavelength light, is an attractive approach for developing a broad‐color expression technology and is widely used in solid‐state lighting, dye‐lasers, and colorful displays. Up to now, many papers have been published reporting various mechanoluminescent materials emitting color of ultraviolet, blue, green, orange, and red. However, the strategies of previous reports have focused on color‐tuning of mechanoluminescent material itself through newly developing inorganic mechanoluminescent compounds. Here, a new strategy for the color manipulation of mechanoluminescence (ML) is introduced by physically combining fluorescent dyes with existing mechanoluminescent materials. An elastomeric zinc sulfide (ZnS) composite is prepared in a polydimethylsiloxane framework with spontaneously diffused 4‐(dicyanomethylene)‐2‐t‐butyl‐6‐(1,1,7,7‐tetramethyljulolidyl‐9‐enyl)‐4H‐pyran (DCJTB), and red luminescence by complete color conversion via DCJTB is demonstrated, which fully absorbed green ML from ZnS. Based on this approach, color‐tuning of ML from red to green is successfully achieved and color expression range is expanded by employing electroluminescence (EL). Various‐color‐emitting EL/ML electromechanical display is demonstrated using color discrepancy between DCJTB employed EL and ML. As the implementation is fairly straightforward, it is believed that present color conversion is a viable and common method to manipulate broader color expression for future ML applications. A new strategy is shown for a candy‐inspired (left image) mechanoluminescence (ML) color manipulation by combining organic red fluorescent dye and zinc sulfide ML material. A red‐dye‐diffused elastomeric bilayer film consisting of a color conversion layer and a green ML light source layer emits clear red luminescence by complete color conversion process when it is stretched (right figure).
      PubDate: 2016-05-23T11:21:42.549067-05:
      DOI: 10.1002/adfm.201601461
       
  • Magnesium Batteries: Toward a Magnesium‐Iodine Battery (Adv. Funct.
           Mater. 27/2016)
    • Authors: Federico Bertasi; Fatemeh Sepehr, Gioele Pagot, Stephen J. Paddison, Vito Di Noto
      Pages: 4859 - 4859
      Abstract: On page 4860, V. Di Noto and co‐workers show the first iodoaluminate ionic liquid for the development of future Mg/I2 secondary batteries. Reversible magnesium deposition/stripping with low overvoltage and high (99.94%) coulombic efficiency is achieved and a detailed investigation of the Mg interaction scenario is reported.
      PubDate: 2016-07-19T01:10:21.07947-05:0
      DOI: 10.1002/adfm.201670174
       
  • Toward a Magnesium‐Iodine Battery
    • Authors: Federico Bertasi; Fatemeh Sepehr, Gioele Pagot, Stephen J. Paddison, Vito Di Noto
      Pages: 4860 - 4865
      Abstract: The quest for new electrolyte and cathode materials is a crucial point for beyond‐lithium‐ion energy storage systems. Following this, an electrolyte for secondary magnesium batteries based on a new iodoaluminate ionic liquid and δ‐MgI2 is reported. Promising electrochemical performance in terms of Mg plating‐stripping, coulombic efficiency, and conductivity, demonstrates the potential of this iodine‐based system for future Mg secondary batteries. Electrolytes for secondary magnesium batteries based on a new iodoaluminate ionic liquid and δ‐MgI2 are reported. Promising electrochemical performance in terms of Mg plating‐stripping, coulombic efficiency, and conductivity, demonstrates the potential of this iodine‐based system for future Mg secondary batteries.
      PubDate: 2016-05-30T08:11:52.132785-05:
      DOI: 10.1002/adfm.201601448
       
  • Stable Organic–Inorganic Perovskite Solar Cells without
           Hole‐Conductor Layer Achieved via Cell Structure Design and Contact
           Engineering
    • Authors: Zhenhua Yu; Bolei Chen, Pei Liu, Changlei Wang, Chenhao Bu, Nian Cheng, Sihang Bai, Yanfa Yan, Xingzhong Zhao
      Pages: 4866 - 4873
      Abstract: Within the past few years, the record efficiency of inorganic–organic perovskite solar cell (PSC) has improved rapidly up to over 20%. However, the viability of commercialization of the PSC technology has been seriously questioned due to the moisture‐ and thermal‐induced instabilities. Here, it is demonstrated that these issues may be mitigated via cell structure design and contact engineering. By employing the hole‐conductor layer‐free cell structure and a bi‐layer back contact consisting of a carbon/CH3NH3I composite layer and a compact hydrophobic carbon layer, the PSCs have shown excellent stability, inhibiting moisture ingression and heat‐induced perovskite degradation. It is found that, the unique bi‐layer contact enables the optimization of perovskite absorbers during thermal stress. As a result, instead of degradation, the devices present enhanced performance under heating at 100 °C for 30 min. The best‐performing cell shows a final efficiency of 13.6% from an initial efficiency of 11.3% after thermal stress. Upon encapsulation, these cells can even retain 90% of the initial efficiencies after water exposure and over 100% initial efficiency under thermal stress at 150 °C for half an hour. This approach provides a facile way for stabilizing the PSCs and opens a door for viable commercialization of the emerging PSC technology. To mitigate the instability of perovskite solar cells via device structure design and contact engineering, a hole‐conductor layer‐free structure of device and a unique bi‐layer hybrid carbon back contact are adopted. The cells not only achieve an enhanced efficiency of 13.6% from the initial 11.3% after 100 °C treatment, but also exhibit excellent moist and thermal stability.
      PubDate: 2016-05-20T09:56:52.897939-05:
      DOI: 10.1002/adfm.201504564
       
  • Selective Enhancement of Inner Tube Photoluminescence in Filled
           Double‐Walled Carbon Nanotubes
    • Authors: Philip Rohringer; Lei Shi, Paola Ayala, Thomas Pichler
      Pages: 4874 - 4881
      Abstract: A highly selective enhancement of the optical response of the inner tubes of double‐walled carbon nanotubes has been identified upon transformation of the residual C atoms inside the hollow core to linear carbon chains (LCC). By varying the growth conditions and using standardized suspensions, it has been observed that this optical response depends sensitively on the tube diameter and LCC growth yield. It is reported how the formation of LCC by postsynthesis annealing at 1400 °C leads to an increase of the photoluminescence (PL) signal of the inner tubes up to a factor of 6 for tubes with (8,3) chirality. This behavior can be attributed to a local charge transfer from the inner tubes to the carbon chains, counterbalancing quenching mechanisms induced by the outer tubes. These findings provide a viable pathway to enhance the low PL quantum yield of double‐walled carbon nanotubes and proof the capability of inner tubes to exhibit photoluminescence. An enhancement of the inner tube's photoluminescence from double‐walled carbon nanotubes is achieved by the incorporation of linear carbon chains into the hollow core of the inner tubes. This effect can be tailored by varying the length of the chains. For appropriate inner tubes with suitable diameters, an amplification of the photoluminescence intensity is found up to a factor of 6 upon filling.
      PubDate: 2016-05-25T15:46:51.867048-05:
      DOI: 10.1002/adfm.201505502
       
  • Composite Nanostructures of TiO2 and ZnO for Water Splitting Application:
           Atomic Layer Deposition Growth and Density Functional Theory Investigation
           
    • Pages: 4882 - 4889
      Abstract: The commercialization of solar fuel devices requires the development of novel engineered photoelectrodes for water splitting applications which are based on redundant, cheap, and environmentally friendly materials. In the current study, a combination of titanium dioxide (TiO2) and zinc oxide (ZnO) onto nanotextured silicon is utilized for a composite electrode with the aim to overcome the individual shortcomings of the respective materials. The properties of conformal coverage of TiO2 and ZnO layers are designed on the atomic scale by the atomic layer deposition technique. The resulting photoanode shows not only promising stability but also nine times higher photocurrents than an equivalent photoanode with a pure TiO2 encapsulation onto the nanostructured silicon. Density functional theory calculations indicate that segregation of TiO2 at the ZnO surfaces is favorable and leads to the stabilization of the ZnO layers in water environments. In conclusion, the novel designed composite material constitutes a promising base for a stable and effective photoanode for the water oxidation reaction. A novel photoanode for water oxidation based on a composite TiO2‐ZnO encapsulation engineered for stabilized photo­electroactivity of the nanostructured silicon substrate is developed. Density functional theory is applied to obtain realistic structural models of the TiO2‐ZnO composite on the atomic scale and the way in which the configurational modifications lead to a better performance of the electrodes is investigated.
      PubDate: 2016-05-24T09:06:10.025958-05:
      DOI: 10.1002/adfm.201505524
       
  • The Formation and Morphology of Nanoparticle Supracrystals
    • Pages: 4890 - 4895
      Abstract: Supracrystals are highly symmetrical ordered superstructures built up from nanoparticles (NPs) via self‐assembly. While the NP assembly has been intensively investigated, the formation mechanism is still not understood. To shed some light onto the formation mechanism, one of the most common supracrystal morphologies, the trigonal structures, as a model system is being used to investigate the formation process in solution. To explain the formation of the trigonal structures and determining the size of the supracrystal seeds formed in solution, the concept of substrate‐affected growth is introduced. Furthermore, the influence of the NP concentration on the seed size is shown and our investigations from Ag toward Au are extended. Trigonal supracrystals are an ideal system to investigate the self‐assembly of nanoparticles in solution into highly symmetrical structures. The proposed substrate‐affected growth mechanism allows determining the size of the crystal seeds built up in solution. The seed size is tuned by the change of the preparation parameters.
      PubDate: 2016-05-23T11:24:37.405208-05:
      DOI: 10.1002/adfm.201600186
       
  • Site‐Selective In Situ Grown Calcium Carbonate Micromodels with
           Tunable Geometry, Porosity, and Wettability
    • Authors: Seung Goo Lee; Hyundo Lee, Ankur Gupta, Sehoon Chang, Patrick S. Doyle
      Pages: 4896 - 4905
      Abstract: Micromodels with simplified porous microfluidic systems are widely used to mimic the underground oil‐reservoir environment for multiphase flow studies, enhanced oil recovery, and reservoir network mapping. However, previous micromodels cannot replicate the length scales and geochemistry of carbonate because of their material limitations. Here a simple method is introduced to create calcium carbonate (CaCO3) micromodels composed of in situ grown CaCO3. CaCO3 nanoparticles/polymer composite microstructures are built in microfluidic channels by photopatterning, and CaCO3 nanoparticles are selectively grown in situ from these microstructures by supplying Ca2+, CO32− ions rich, supersaturated solutions. This approach enables us to fabricate synthetic CaCO3 reservoir micromodels having dynamically tunable geometries with submicrometer pore‐length scales and controlled wettability. Using this new method, acid fracturing and an immiscible fluid displacement process are demonstrated used in real oil field applications to visualize pore‐scale fluid–carbonate interactions in real time. Calcium carbonate (CaCO3) micro­models are fabricated by a photolithographic technique and by a subsequent in situ growth of CaCO3. The fast and selective growth of CaCO3 on the multiple CaCO3 posts in a microchannel requires providing well‐controlled Ca2+, CO32− ions rich/supersaturated solutions.
      PubDate: 2016-05-20T09:56:47.181949-05:
      DOI: 10.1002/adfm.201600573
       
  • Stimulating Acrylic Elastomers by a Triboelectric Nanogenerator –
           Toward Self‐Powered Electronic Skin and Artificial Muscle
    • Authors: Xiangyu Chen; Tao Jiang, Yanyan Yao, Liang Xu, Zhenfu Zhao, Zhong Lin Wang
      Pages: 4906 - 4913
      Abstract: Dielectric elastomers are a type of actuator materials that exhibit excellent performance as artificial muscles, but a high driving voltage is required for their operation. By using the amazingly high output voltage generated from a triboelectric nanogenerator (TENG), a thin film dielectric elastomer actuator (DEA) can be directly driven by the contact‐separation motion of TENG, demonstrating a self‐powered actuation system. A TENG with a tribo surface area of 100 cm2 can induce an expansion strain of 14.5% for the DEA samples (electrode diameter of 0.6 cm) when the system works stably within the contact‐separation velocity ranging from 0.1 to 10 cm s−1. Finally, two simple prototypes of an intelligent switch and a self‐powered clamper based on the TENG and DEA are demonstrated. These results prove that the dielectric elastomer is an ideal material to work together with TENG and thereby the fabricated actuation system can potentially be applied to the field of electronic skin and soft robotics. By using the amazingly high output voltage generated from a triboelectric nanogenerator (TENG), a thin film dielectric elastomer actuator (DEA) can be directly driven by the contact–separation motion of the TENG, demonstrating a self‐powered actuation system. This DEA‐TENG actuation system can potentially be applied to the field of electronic skin and soft robotics.
      PubDate: 2016-05-25T15:46:34.354997-05:
      DOI: 10.1002/adfm.201600624
       
  • Mechanical Properties of Highly Porous Super Liquid‐Repellent
           Surfaces
    • Pages: 4914 - 4922
      Abstract: Surfaces with self‐cleaning properties are desirable for many applications. Conceptually, super liquid‐repellent surfaces are required to be highly porous on the nano‐ or micrometer scale, which inherently makes them mechanically weak. Optimizing the balance of mechanical strength and liquid repellency is a core aspect toward applications. However, quantitative mechanical testing of porous, super liquid‐repellent surfaces is challenging due to their high surface roughness at different length scales and low stress tolerance. For this reason, mechanical testing is often performed qualitatively. Here, the mechanical responses of soot‐templated super liquid‐repellent surfaces are studied qualitatively by pencil and finger scratching and quantitatively by atomic force microscopy, colloidal probe force measurements, and nanoindentation. In particular, colloidal probe force measurements cover the relevant force and length scales. The effective elastic modulus, the plastic work Wplastic and the effective adhesive work Wadhesive are quantified. By combining quantitative information from force measurements with measurements of surface wetting properties, it is shown that mechanical strength can be balanced against low wettability by tuning the reaction parameters. Super liquid‐repellent surfaces have self‐cleaning properties and are desirable for many applications. These surfaces are highly porous on the nano‐ or micrometer scale, what inherently makes them mechanically weak. It is demonstrated that force‐sensitive measurements using the colloidal probe technique can be used to optimize for mechanical strength and low wettability by tuning the reaction parameters of soot‐templated surfaces.
      PubDate: 2016-05-24T08:56:52.389861-05:
      DOI: 10.1002/adfm.201600627
       
  • Inkjet Printing of a Highly Loaded Palladium Ink for Integrated,
           Low‐Cost pH Sensors
    • Pages: 4923 - 4933
      Abstract: An inkjet printing process for depositing palladium (Pd) thin films from a highly loaded ink (>14 wt%) is reported. The viscosity and surface tension of a Pd‐organic precursor solution is adjusted using toluene to form a printable and stable ink. A two‐step thermolysis process is developed to convert the printed ink to continuous and uniform Pd films with good adhesion to different substrates. Using only one printing pass, a low electrical resistivity of 2.6 μΩ m of the Pd film is obtained. To demonstrate the electrochemical pH sensing application, the surfaces of the printed Pd films are oxidized for ion‐to‐electron transduction and the underlying layer is left for electron conduction. Then, solid‐state reference electrodes are integrated beside the bifunctional Pd electrodes by inkjet printing. These potentiometric sensors have sensitivities of 60.6 ± 0.1 and 57 ± 0.6 mV pH−1 on glass and polyimide substrates, and short response times of 11 and 6 s, respectively. Also, accurate pH values of real water samples are obtained by using the printed sensors with a low‐cost multimeter. These results indicate that the facile and cost‐effective inkjet printing and integration techniques may be applied in fabricating future electrochemical monitoring systems for environmental parameters and human health conditions. The inkjet printing of a highly loaded palladium ink is developed to deposit homogenous and low‐resistance palladium films on rigid and flexible substrates. A bilayer structure is formed in the printed palladium films after annealing. The oxide‐rich surface is pH‐sensitive and the bottom layer is electron‐conductive. The inkjet‐printed and integrated pH sensors show accurate measurement results for real water samples.
      PubDate: 2016-05-24T08:56:46.977539-05:
      DOI: 10.1002/adfm.201600657
       
  • Monitoring the Formation of a CH3NH3PbI3–xClx Perovskite during
           Thermal Annealing Using X‐Ray Scattering
    • Authors: Alexander T. Barrows; Samuele Lilliu, Andrew J. Pearson, David Babonneau, Alan D. F. Dunbar, David G. Lidzey
      Pages: 4934 - 4942
      Abstract: Grazing incidence wide and small angle X‐ray scattering (GIWAXS and GISAXS) measurements have been used to study the crystallization kinetics of the organolead halide perovskite CH3NH3PbI3–xClx during thermal annealing. In situ GIWAXS measurements recorded during annealing are used to characterize and quantify the transition from a crystalline precursor to the perovskite structure. In situ GISAXS measurements indicate an evolution of crystallite sizes during annealing, with the number of crystallites having sizes between 30 and 400 nm increasing through the annealing process. Using ex situ scanning electron microscopy, this evolution in length scales is confirmed and a concurrent increase in film surface coverage is observed, a parameter crucial for efficient solar cell performance. A series of photovoltaic devices are then fabricated in which perovskite films have been annealed for different times, and variations in device performance are explained on the basis of X‐ray scattering measurements. Crystallization of the perovskite CH3NH3PbI3–xClx during thermal annealing of a precursor film is studied using in situ grazing incidence wide angle and small angle X‐ray scattering measurements. These results can explain the evolution of device performance with annealing time, and optimized films lead to solar cells with average power conversion efficiencies of over 12%.
      PubDate: 2016-05-26T01:01:03.928168-05:
      DOI: 10.1002/adfm.201601309
       
  • Freestanding Graphitic Carbon Nitride Photonic Crystals for Enhanced
           Photocatalysis
    • Authors: Lu Sun; Meijia Yang, Jianfeng Huang, Dingshan Yu, Wei Hong, Xudong Chen
      Pages: 4943 - 4950
      Abstract: Graphitic carbon nitride (g‐C3N4) has attracted tremendous attention in photocatalysis due to its extraordinary features, such as good thermal and chemical stability, metal‐free composition, and easy preparation. However, the photocatalytic performance of g‐C3N4 is still restricted by the limited surface area, inefficient visible light absorption, and high recombination rate of photoinduced charge carriers. Herein, a facile synthesis to produce freestanding g‐C3N4 photonic crystals (PCs) by crack‐free, highly ordered colloid crystals templating is reported. The PC structure succeeded from the silica opals induces bicontinuous framework, stronger optical absorption, and increase in the lifetime of photoexcited charge carriers compared to that of the bulk g‐C3N4, while the chemical structure remains similar to that of the bulk g‐C3N4. As such, the g‐C3N4 PCs have a much higher photodegradation kinetic of methyl orange and photocatalytic hydrogen production rate which is nearly nine times the rate of bulk g‐C3N4. Freestanding graphitic carbon nitride photonic crystals are synthesized by crack‐free, highly ordered colloid crystals templating and exhibit an order of magnitude superior photocatalytic activity to the bulk graphitic carbon nitride in photodegradation and hydrogen evolution under visible light due to the 3D interconnected network, slow photon effects, and depressed photoluminescence within the stop band region.
      PubDate: 2016-05-18T14:34:55.552089-05:
      DOI: 10.1002/adfm.201600894
       
  • Photoinduced Absorption Spectroscopy of CoPi on BiVO4: The Function of
           CoPi during Water Oxidation
    • Authors: Yimeng Ma; Andreas Kafizas, Stephanie R. Pendlebury, Florian Le Formal, James R. Durrant
      Pages: 4951 - 4960
      Abstract: This paper employs photoinduced absorption and electrochemical techniques to analyze the charge carrier dynamics that drive photoelectrochemical water oxidation on bismuth vanadate (BiVO4), both with and without cobalt phosphate (CoPi) co‐catalyst. These results are correlated with spectroelectrochemical measurements of CoII oxidation to CoIII in a CoPi/FTO (fluorine doped tin oxide) electrode during dark electrocatalytic water oxidation. Electrocatalytic water oxidation exhibits a non‐linear dependence on CoIII density, with a sharp onset at 1 × 1017 CoIII cm−2. These results are compared quantitatively with the degree of CoPi oxidation observed under conditions of photoinduced water oxidation on CoPi–BiVO4 photoanodes. For the CoPi–BiVO4 photoanodes studied herein, ≤5% of water oxidation proceeds from CoPi sites, making the BiVO4 surface the predominant water oxidation site. This study highlights two key factors that limit the ability of CoPi to improve the catalytic performance of BiVO4: 1) the kinetics of hole transfer from the BiVO4 to the CoPi layer are too slow to effectively compete with direct water oxidation from BiVO4; 2) the slow water oxidation kinetics of CoPi result in a large accumulation of CoIII states, causing an increase in recombination. Addressing these factors will be essential for improving the performance of CoPi on photoanodes for solar‐driven water oxidation. Photoinduced absorption spectroscopy is employed to investigate charge carrier dynamics in CoPi‐modified BiVO4 photoanodes for water oxidation under simulated working condition. The quantity of oxidized CoPi by BiVO4 holes is found to be low and incapable of driving efficient water oxidation. Therefore, almost no catalytic function from the CoPi layer is present in CoPi‐modified BiVO4 under working photoelectrochemical conditions.
      PubDate: 2016-05-17T01:20:32.514051-05:
      DOI: 10.1002/adfm.201600711
       
  • Nanostructure/Swelling Relationships of Bulk and Thin‐Film PFSA
           Ionomers
    • Authors: Ahmet Kusoglu; Thomas J. Dursch, Adam Z. Weber
      Pages: 4961 - 4975
      Abstract: Perfluorinated sulfonic acid (PFSA) ionomers are the most widely used solid electrolyte in electrochemical technologies due to their remarkable ionic conductivity with simultanous mechanical stability, imparted by their phase‐separated morphology. In this work, the morphology and swelling of PFSA ionomers (Nafion and 3M) as bulk membranes (>10 μm) and dispersion‐cast thin films (
      PubDate: 2016-05-17T08:26:01.38352-05:0
      DOI: 10.1002/adfm.201600861
       
  • Strong, Machinable Carbon Aerogels for High Performance Supercapacitors
    • Authors: Christine H. J. Kim; Dandan Zhao, Gyeonghee Lee, Jie Liu
      Pages: 4976 - 4983
      Abstract: Designing macroscopic, 3D porous conductive materials with high mechanical strength is of great importance in many fields, including energy storage, catalysis, etc. This study reports a novel approach to fabricate polyaniline‐coated 3D carbon x‐aerogels, a special type of aerogels with mechanically strong, highly cross‐linked structure that allows the originally brittle aerogels machinable. This approach is accomplished by introducing a small amount of graphene into the sol–gel process of resorcinol and formaldehyde, followed by physical activation and subsequent cross‐linking with polyaniline via electropolymerization. The resulting x‐aerogels are not only porous and conductive, but also mechanically robust with high compressibility and fast recovery. The strong combination of these properties makes the x‐aerogels promising for high performance supercapacitors that are designed to provide additional functionality for wearable and portable electronics. Such multi‐functionality leads to a significant increase in electrochemical performance, in particular high volumetric capacitance, which results from the more densely packed electroactive structure in three dimensions. More importantly, monoliths of carbon x‐aerogels are machinable into thin slices without losing their properties, thus enabling effective integration into devices with different sizes and shapes. Strong, machinable carbon aerogels are reported, developed to be not only porous and conductive, but also mechanically robust with high compressibility and fast recovery. The synergistic combination of these properties makes the aerogels promising for high performance supercapacitors that are designed to provide additional functionality for wearable and portable electronics.
      PubDate: 2016-05-23T11:22:45.921304-05:
      DOI: 10.1002/adfm.201601010
       
  • High‐Mobility Naphthalene Diimide and
           Selenophene‐Vinylene‐Selenophene‐Based Conjugated
           Polymer: n‐Channel Organic Field‐Effect Transistors and
           Structure–Property Relationship
    • Pages: 4984 - 4997
      Abstract: Interdependence of chemical structure, thin‐film morphology, and transport properties is a key, yet often elusive aspect characterizing the design and development of high‐mobility, solution‐processed polymers for large‐area and flexible electronics applications. There is a specific need to achieve >1 cm2 V−1 s−1 field‐effect mobilities (μ) at low processing temperatures in combination with environmental stability, especially in the case of electron‐transporting polymers, which are still lagging behind hole transporting materials. Here, the synthesis of a naphthalene‐diimide based donor–acceptor copolymer characterized by a selenophene vinylene selenophene donor moiety is reported. Optimized field‐effect transistors show maximum μ of 2.4 cm2 V−1 s−1 and promising ambient stability. A very marked film structural evolution is revealed with increasing annealing temperature, with evidence of a remarkable 3D crystallinity above 180 °C. Conversely, transport properties are found to be substantially optimized at 150 °C, with limited gain at higher temperature. This discrepancy is rationalized by the presence of a surface‐segregated prevalently edge‐on packed polymer phase, dominating the device accumulated channel. This study therefore serves the purpose of presenting a promising, high‐electron‐mobility copolymer that is processable at relatively low temperatures, and of clearly highlighting the necessity of specifically investigating channel morphology in assessing the structure–property nexus in semiconducting polymer thin films. Promisingly air‐stable, low‐temperature solution processed n‐type field‐effect transistors with mobility up to 2.4 cm2 V−1 s−1 are demonstrated thanks to the synthesis of a naphthalene diimide and selenophene‐vinylene‐selenophene‐based conjugated copolymer. A temperature induced, remarkable 3D crystallinity of thin films is unveiled. Interestingly however, transport is dominated by the interconnectivity of a segregated, edge‐on polymer phase where charge follows orientational domains rather insensitive to annealing conditions.
      PubDate: 2016-05-18T14:34:31.923684-05:
      DOI: 10.1002/adfm.201601144
       
  • Electrocatalysis: Overall Water Splitting Catalyzed Efficiently by an
           Ultrathin Nanosheet‐Built, Hollow Ni3S2‐Based Electrocatalyst
           (Adv. Funct. Mater. 27/2016)
    • Pages: 4999 - 4999
      Abstract: T. Asefa, X. Zou, and co‐workers present a nickel foam‐supported, ultrathin nanosheet‐based, hollow Ni3S2‐based electrocatalyst for overall water splitting on page 4839. By using this material as electrocatalyst both at the cathode and the anode sides of an electrolyzer, a water‐splitting efficiency is achieved that outperforms even noble‐metal‐based Pt/C and IrOx/C benchmark electrolyzers. This result represents an important step toward efficient, non‐noble metal electrocatalyst‐based overall water splitting.
      PubDate: 2016-07-19T01:10:21.121234-05:
      DOI: 10.1002/adfm.201670175
       
  • Color Conversion: Mechanoluminescence Color Conversion by Spontaneous
           Fluorescent‐Dye‐Diffusion in Elastomeric Zinc Sulfide
           Composite (Adv. Funct. Mater. 27/2016)
    • Pages: 5000 - 5000
      Abstract: S. M. Jeong and co‐workers demonstrate on page 4848 the complete color conversion of mechanoluminescence (ML) from green to red using spontaneous fluorescent‐dye‐diffusion in zinc sulfide (ZnS) microparticles embedded in polydimethylsiloxane (PDMS) framework. The red luminescence could be achieved by 4‐(dicyanomethylene)‐2‐t‐butyl‐6‐(1,1,7,7‐tetramethyljulolidyl‐9‐enyl)‐4H‐pyran (DCJTB) fully absorbing green mechanoluminescence (ML) from ZnS. The straightforward approach may be applied to manipulate broader color expression for future ML applications.
      PubDate: 2016-07-19T01:10:17.987568-05:
      DOI: 10.1002/adfm.201670176
       
 
 
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