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  Subjects -> CHEMISTRY (Total: 845 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (596 journals)
    - CRYSTALLOGRAPHY (22 journals)
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CHEMISTRY (596 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: 21)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 15)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 22)
ACS Macro Letters     Full-text available via subscription   (Followers: 18)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 31)
ACS Nano     Full-text available via subscription   (Followers: 152)
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: 7)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 4)
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: 40)
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: 7)
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: 14)
Advances in Nanoparticles     Open Access   (Followers: 11)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 12)
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: 12)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 1)
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 2)
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 Applied Sciences     Open Access   (Followers: 26)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
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: 7)
Anadolu University Journal of Science and Technology     Open Access  
Analyst     Full-text available via subscription   (Followers: 41)
Angewandte Chemie     Hybrid Journal   (Followers: 108)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 156)
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: 22)
Applied Surface Science     Hybrid Journal   (Followers: 20)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
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: 195)
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: 15)
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: 90)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 79)
Bioorganic Chemistry     Hybrid Journal   (Followers: 9)
Biopolymers     Hybrid Journal   (Followers: 16)
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: 23)
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: 3)
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: 64)
Catalysis for Sustainable Energy     Open Access   (Followers: 4)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 6)
Catalysis Science and Technology     Free   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 5)
Cellulose     Hybrid Journal   (Followers: 4)
Central European Journal of Chemistry     Hybrid Journal   (Followers: 6)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription  
ChemCatChem     Hybrid Journal   (Followers: 4)
Chemical and Engineering News     Free   (Followers: 10)
Chemical Bulletin of Kazakh National University     Open Access  
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: 15)
Chemical Reviews     Full-text available via subscription   (Followers: 127)
Chemical Science     Open Access   (Followers: 17)
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: 54)
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: 102)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 11)
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: 132)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 8)
Chemistry World     Full-text available via subscription   (Followers: 21)
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: 14)
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: 6)
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)
Elements     Full-text available via subscription  
Environmental Chemistry     Hybrid Journal   (Followers: 5)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 2)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 3)

        1 2 3 | Last

Journal Cover Advanced Functional Materials
  [SJR: 4.682]   [H-I: 156]   [40 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  [1597 journals]
  • Downscaling and Charge Transport in Nanostructured Ferroelectric Memory
           Diodes Fabricated by Solution Micromolding
    • Authors: Thomas Lenz; Matteo Ghittorelli, Frank Simon Benneckendorf, Kamal Asadi, Christian Kasparek, Gunnar Glasser, Paul W. M. Blom, Fabrizio Torricelli, Dago M. de Leeuw
      Abstract: Ferroelectric polymer memory diodes are interface devices where charge injection into the organic semiconductor is controlled by the stray electric field of the ferroelectric polymer. Key to high current density and current modulation is the areal density of well‐defined interfaces. Here, bistable diodes are fabricated by using the soft lithography method solution micromolding. First, the semiconducting polymer poly(9,9‐dioctylfluorene) is patterned into linear gratings. Subsequently, bilinear arrays are obtained by backfilling with the ferroelectric polymer poly(vinylidenefluoride‐co‐trifluoroethylene). The lateral feature size is scaled down from 2 μm to 500 nm. Comprising memory diodes show rectifying J–V characteristics with an On‐current density larger than 103 A m−2 and an On/Off current ratio exceeding 103. The charge transport is explained by 2D numerical simulations. Since the dependence of polarization on electric field is explicitly taken into account, entire J–V characteristics can be quantitatively described. The simulations reveal that rectifying J–V characteristics are inherently related to the concave shape of the patterned ferroelectric polymer. It is argued that the exponential increase in current density with decreasing feature size can be due to confinement of the semiconductor. High On‐current density combined with downscaling, rectification, and simple fabrication yield new opportunities for low‐cost integration of high‐density solution‐processed memories. Ferroelectric polymer memory diodes are fabricated by solution micromolding. The lateral feature size is scaled down from 2 μm to 500 nm. The charge transport is explained by 2D numerical simulations. Since the dependence of polarization on electric field is explicitly taken into account, entire J–V characteristics can for the first time be described quantitatively.
      PubDate: 2016-05-19T10:26:07.118043-05:
      DOI: 10.1002/adfm.201601224
       
  • Precisely Controlled Hydration Water for Performance Improvement of
           Organic–Inorganic Perovskite Solar Cells
    • Authors: Li Ling; Sijian Yuan, Pengfei Wang, Huotian Zhang, Li Tu, Jiao Wang, Yiqiang Zhan, Lirong Zheng
      Abstract: Recently, intensive studies on the role of water molecule in the formation of organic–inorganic perovskite film have been reported. However, not only the contradictive phenomena but also the complex processing technique has hindered the widespread use of water molecule in perovskite preparation. Here the hydration water is introduced into the precursors instead of water. By precisely controlling the content of hydration water, a smoother and more uniform perovskite film is obtained through a simple one‐step spin coating method. The improvement of perovskite film quality leads to highly efficient planar perovskite solar cells. Summing up the device studies and the investigation of morphology, crystallization, and optical properties, the impact of water molecule in the formation of perovskite crystal and consequences of device performance is understood. Due to its universal adaptability and simplified process, precise control of hydration water is therefore of great utility to high quality perovskite films fabrication and large‐scale production of this upcoming photovoltaic technology. The content of hydration water is carefully controlled in precursor solution. The findings reveal that the hydration water has played an essential role in the formation of perovskite film. With an optimum amount of hydration water, a high quality perovskite film with better uniformity and smoother surface is formed. Based on it, an efficient perovskite solar cell is fabricated.
      PubDate: 2016-05-19T10:25:51.629819-05:
      DOI: 10.1002/adfm.201601557
       
  • Highly Emissive Nd3+‐Sensitized Multilayered Upconversion
           Nanoparticles for Efficient 795 nm Operated Photodynamic Therapy
    • Abstract: Photodynamic therapy (PDT) is a noninvasive and site‐specific therapeutic technique for the clinical treatment of various of superficial diseases. In order to tuning the operation wavelength and improve the tissue penetration of PDT, rare‐earth doped upconversion nanoparticles (UCNPs) with strong anti‐stokes emission are introduced in PDT recently. However, the conventional Yb3+‐sensitized UCNPs are excited at 980 nm which is overlapped with the absorption of water, thus resulting in strong overheating effect. Herein, a convenient but effective design to obtain highly emissive 795 nm excited Nd3+‐sensitized UCNPs (NaYF4:Yb,Er@NaYF4:Yb0.1Nd0.4@NaYF4) is reported, which provides about six times enhanced upconversion luminescence, comparing with traditional UCNPs (NaYF4:Yb,Er@NaYF4). A colloidal stable and non‐leaking PDT nanoplatform is fabricated later through a highly PEGylated mesoporous silica layer with covalently linked photosensitizer (Rose Bengal derivative). With as‐prepared Nd3+‐sensitized UCNPs, the nanoplatform can produce singlet oxygen more effective than traditional UCNPs. Significant higher penetration depth and lower overheating are demonstrated as well. All these features make as‐prepared nanocomposites excellent platform for PDT treatment. In addition, the nanoplatform with uniform size, high surface area, and excellent colloidal stability can be extended for other biomedical applications, such as imaging probes, biosensors, and drug delivery vehicles. Nd3+‐sensitized multilayered upconversion nanoparticles excitable at 795 nm, can provide six times enhanced upconversion luminescence comparing with traditional NaYF4:Yb,Er@NaYF4. A highly PEGylated mesoporous silica layer with covalently bonded photosensitizers is coated on them to fabricate a colloidal stable and non‐leaking nanoplatform for photodynamic therapy with high penetration depth and low overheating.
      PubDate: 2016-05-18T14:35:10.097228-05:
      DOI: 10.1002/adfm.201600464
       
  • Ternary Oxide Nanocrystals: Universal Laser‐Hydrothermal Synthesis,
           Optoelectronic and Electrochemical Applications
    • Authors: Muchen Rui; Xiaoming Li, Lin Gan, Tianyou Zhai, Haibo Zeng
      Abstract: Ternary oxide nanocrystals (TONs) have received growing attention for their great potential applications in optoelectronics and electrochemistry despite the current scarcity of universal, facile, and green synthesis methods. Here, we introduce a universal laser‐hydrothermal approach for various TONs and demonstrate their potential for high‐performance photodetectors (PDs) and pseudocapacitors. The obtained clean surface is derived by laser ablation in liquid (LAL) and subsequent hydrothermal growth. The LAL‐generated precursors contain many kinds of highly reactive species, including H+, OH−, metal ions, and clusters, which facilitate the fast and facile formation of various TONs in the subsequent hydrothermal process. The universality of the method is systematically proven by the synthesis of a series of TONs, including Zn2GeO4, NiCo2O4, Zn2SnO4, ZnFe2O4, ZnMnO3, and Fe2GeO4. Significantly, the absence of chemical additives, such as surfactants, guarantees highly clean surfaces, which further benefits the electron transport through the nanocrystals, and thus in the resultant devices. This is also exemplified by a Zn2GeO4‐nanorod‐based, deep‐ultraviolet PD and NiCo2O4 nanocrystal supercapacitors. Various ternary oxide nanocrystals can easily be prepared by this universal synthesis procedure. The synthesis combines laser ablation in liquid (LAL) with short‐time hydrothermal growth. LAL generates highly reactive precursors that facilitate the formation of various ternary oxide nanocrystals in the subsequent fast hydrothermal process. The absence of chemical additives during the whole process results in a highly clean surface, which greatly improves the electron transport among the nanocrystals.
      PubDate: 2016-05-18T14:35:03.974877-05:
      DOI: 10.1002/adfm.201600785
       
  • Freestanding Graphitic Carbon Nitride Photonic Crystals for Enhanced
           Photocatalysis
    • Authors: Lu Sun; Meijia Yang, Jianfeng Huang, Dingshan Yu, Wei Hong, Xudong Chen
      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
       
  • Unique Necklace‐Like Phenol Formaldehyde Resin Nanofibers: Scalable
           Templating Synthesis, Casting Films, and Their Superhydrophobic Property
    • Abstract: 1D necklace‐like nanostructures have exhibited different potential applications due to their unique geometry and property. However, their macroscopic and controllable synthesis has been a challenge. Herein, a facile and scalable template‐directed hydrothermal process is reported to synthesize a series of necklace‐like phenol‐formaldehyde resin (PFR) wrapped nanocables. The 1D templates involved in the synthesis can be various, such as tellurium nanowires (TeNWs), silver nanowires, and carbon nanotubes. After removal of the TeNWs template, pure PFR necklace‐like nanofibers with different morphologies can be prepared. Owning to their multiscale roughness and formed 3D network structures, such necklace‐like PFR nanofibers can be further used as building blocks for constructing robust superhydrophobic coatings with excellent mechanical properties on various substrates. Necklace‐like phenol formaldehyde resin nanofibers with controllable morphologies can be synthesized on a large scale by a template‐directed hydrothermal method (see the figure), which exhibits great application for constructing robust superhydrophobic surfaces on a variety of substrates.
      PubDate: 2016-05-18T14:34:49.88028-05:0
      DOI: 10.1002/adfm.201600907
       
  • Cobalt‐Doping in Molybdenum‐Carbide Nanowires Toward Efficient
           Electrocatalytic Hydrogen Evolution
    • Authors: Huanlei Lin; Ning Liu, Zhangping Shi, Yulin Guo, Yi Tang, Qingsheng Gao
      Abstract: Efficient hydrogen evolution reaction (HER) over noble‐metal‐free electrocatalysts provides one of the most promising pathways to face the energy crisis. Herein, facile cobalt‐doping based on Co‐modified MoOx–amine precursors is developed to optimize the electrochemical HER over Mo2C nanowires. The effective Co‐doping into Mo2C crystal structure increases the electron density around Fermi level, resulting in the reduced strength of Mo–H for facilitated HER kinetics. As expected, the Co‐Mo2C nanowires with an optimal Co/Mo ratio of 0.020 display a low overpotential (η10 = 140 and 118 mV for reaching a current density of –10 mA cm−2; η100 = 200 and 195 mV for reaching a current density of –100 mA cm−2), a small Tafel slope (39 and 44 mV dec−1), and a low onset overpotential (40 and 25 mV) in 0.5 m H2SO4 and 1.0 m KOH, respectively. This work highlights a feasible strategy to explore efficient electrocatalysts via engineering on composition and nanostructure. Cobalt‐doping into Mo2C increases the electron density of Mo and optimizes the electrocatalytic hydrogen evolution over Mo2C nanowires. With an optimal Co/Mo ratio, the Co‐Mo2C nanowires exhibit high activity and good stability in both acidic and basic electrolytes, performing among the best of current noble‐metal‐free electrocatalysts.
      PubDate: 2016-05-18T14:34:44.831991-05:
      DOI: 10.1002/adfm.201600915
       
  • High‐Mobility Naphthalene Diimide and
           Selenophene‐Vinylene‐Selenophene‐Based Conjugated
           Polymer: n‐Channel Organic Field‐Effect Transistors and
           Structure–Property Relationship
    • 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
       
  • Ultrafast Discharge/Charge Rate and Robust Cycle Life for
           High‐Performance Energy Storage Using Ultrafine Nanocrystals on the
           Binder‐Free Porous Graphene Foam
    • Abstract: A hierarchical architecture fabricated by integrating ultrafine titanium dioxide (TiO2) nanocrystals with the binder‐free macroporous graphene (PG) network foam for high‐performance energy storage is demonstrated, where mesoporous open channels connected to the PG facilitate rapid ionic transfer during the Li‐ion insertion/extraction process. Moreover, the binder‐free conductive PG network in direct contact with a current collector provides ultrafast electronic transfer. This structure leads to unprecedented cycle stability, with the capacity preserved with nearly 100% Coulombic efficiency over 10 000 Li‐ion insertion/extraction cycles. Moreover, it is proven to be very stable while cycling 10 to 100‐fold longer compared to typical electrode structures for batteries. This facilitates ultrafast charge/discharge rate capability even at a high current rate giving a very short charge/discharge time of 40 s. Density functional theory calculations also clarify that Li ions migrate into the TiO2–PG interface then stabilizing its binder‐free interface and that the Li ion diffusion occurs via a concerted mechanism, thus resulting in the ultrafast discharge/charge rate capability of the Li ions into ultrafine nanocrystals. A hierarchical architecture fabricated by integrating ultrafine (≈6 nm) TiO2 nanoparticles (NPs) on the binder‐free macroporous graphene (PG) network foam for high‐performance energy storage enabling ultrafast rate and robust cycle life is reported, where the mesoporous open channels created by ultrafine NPs and also the binder‐free conductive PG network facilitate fast ionic transfer during Li‐ion insertion/extraction.
      PubDate: 2016-05-18T14:34:19.308423-05:
      DOI: 10.1002/adfm.201601355
       
  • Masthead: (Adv. Funct. Mater. 19/2016)
    • PubDate: 2016-05-18T02:26:28.415223-05:
      DOI: 10.1002/adfm.201670121
       
  • Organometal Halide Perovskite Quantum Dot Light‐Emitting Diodes
    • Abstract: Organometal halide perovskites quantum dots (OHP‐QDs) with bright, color‐tunable, and narrow‐band photoluminescence have significant advantages in display, lighting, and laser applications. Due to sparse concentrations and difficulties in the enrichment of OHP‐QDs, production of large‐area uniform films of OHP‐QDs is a challenging task, which largely impedes their use in electroluminescence devices. Here, a simple dip‐coating method has been reported to effectively fabricate large‐area uniform films of OHP‐QDs. Using this technique, multicolor OHP‐QDs light‐emitting diodes (OQ‐LEDs) emitting in blue, blue‐green, green, orange, and red color have been successfully produced by simply tuning the halide composition or size of QDs. The blue, green, and red OQ‐LEDs exhibited, respectively, a maximum luminance of 2673, 2398, and 986 cd m−2 at a current efficiency of 4.01, 3.72, and 1.52 cd A−1, and an external quantum efficiency of 1.38%, 1.06%, and 0.53%, which are much better than most LEDs based on OHP films. The packaged OQ‐LEDs show long‐term stability in air (humidity ≈50%) for at least 7 d. The results demonstrate the great potential of the dip‐coating method to fabricate large‐area uniform films for various QDs. The high‐efficiency OQ‐LEDs also demonstrate the promising potential of OHP‐QDs for low‐cost display, lighting, and optical communication applications. Organometal halide perovskite quantum dot (OHP‐QDs)‐based light‐emitting diodes (LEDs) are developed using a simple dip‐coating method. The OHP‐QDs‐based LEDs show multicolor emission from blue, green to red by tuning the composition or size of the OHP‐QDs. The packaged devices also exhibit robust stability under continuous bias in air for at least 7 d.
      PubDate: 2016-05-17T08:26:28.817472-05:
      DOI: 10.1002/adfm.201601054
       
  • Nanostructure/Swelling Relationships of Bulk and Thin‐Film PFSA
           Ionomers
    • Authors: Ahmet Kusoglu; Thomas J. Dursch, Adam Z. Weber
      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
       
  • Self‐Healing Properties of Protein Resin with Soy Protein
           Isolate‐Loaded Poly(d,l‐lactide‐co‐glycolide)
           Microcapsules
    • Authors: Joo Ran Kim; Anil N. Netravali
      Abstract: Self‐healing soy protein isolate (SPI)‐based “green” thermoset resin is developed using poly(d,l‐lactide‐co‐glycolide)(PLGA) microcapsules containing SPI, as crack healant. The SPI–PLGA microcapsules with an average diameter of 778 nm that contain sub‐capsules are prepared using a water‐in‐oil‐in‐water double‐emulsion solvent evaporation technique. The encapsulation efficiency is found to be high, up to 89%. Thermoset green SPI resin containing the SPI–PLGA microcapsules successfully arrests and retards the microcracks. The healing efficiency is investigated using mode I fracture toughness test for resins containing different concentrations of microcapsules from 5 to 20 wt% and glutaraldehyde as a crosslinker at 9 or 12 wt%. The SPI resin containing 12 wt% glutaraldehyde and 15 wt% microcapsules shows self‐healing efficiency of up to 48%. It is observed that the SPI released from SPI–PLGA microcapsules can react with the excess glutaraldehyde present in the resin when the two come in contact within the microcracks and bridge the two fracture surfaces. The results of this study show for the first time that SPI–PLGA microcapsules can self‐heal protein‐based green resins. The same method can be extended to self‐heal other proteins as well as protein‐based green composites resulting in higher fracture toughness and longer useful life. A green, self‐healing thermoset soy protein resin is developed using soy protein isolate‐loaded poly(d,l‐lactide‐co‐glycolide) microcapsules and glutaraldehyde as a crosslinker. The results show that two fracture surfaces are bridged by the healant released from microcapsules when microcracks are formed under stress. The healing efficiency of up to 48% is obtained according to the fracture toughness test.
      PubDate: 2016-05-17T08:25:42.771596-05:
      DOI: 10.1002/adfm.201600465
       
  • All‐Solution‐Processed Random Si Nanopyramids for Excellent
           Light Trapping in Ultrathin Solar Cells
    • Authors: Sihua Zhong; Wenjie Wang, Yufeng Zhuang, Zengguang Huang, Wenzhong Shen
      Abstract: Si nanopyramids have been suggested as one of the most promising Si nanostructures to realize high‐efficient ultrathin solar cells or photodetectors due to their low surface area enhancement and outstanding ability to enhance light absorption. However, the present techniques to fabricate Si nanopyramids are either complex or expensive. In parallel, disordered nanostructures are believed to be extremely effective to realize broadband light trapping for solar cells. Here, a simple and cost‐effective method is presented to form random Si nanopyramids based on an all‐solution process, the mechanism behind which is the successful transfer of the generation site of bubbles from Si surface to the introduced Ag nanoparticles so that OH− can react with the entire Si surface to naturally form random and dense Si nucleus. For optical performance, it is experimentally demonstrated that the random Si nanopyramid textured ultrathin crystalline Si (c‐Si) can achieve light trapping approaching the Lambertian limit. Importantly, it is revealed, by numerical calculations, that random Si nanopyramids outperform periodic ones on broadband light absorption due to more excited optical resonance modes. The finding provides a new opportunity to improve the performance of ultrathin c‐Si solar cells with a simpler process and lower cost. An all‐solution‐processed method to form Si nanopyramids is proposed. The method is simple and cost‐effective. The success lies in the transfer of generation site of H2 bubbles from Si surface to Ag nanoparticles. The resultant random Si nanopyramids provide superior broadband light trapping effect, even better than its periodic counterpart, achieving near‐Lambertian light absorption in thin‐film c‐Si.
      PubDate: 2016-05-17T01:20:46.490216-05:
      DOI: 10.1002/adfm.201505538
       
  • 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
      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
       
  • Toward Flexible Spintronics: Perpendicularly Magnetized Synthetic
           Antiferromagnetic Thin Films and Nanowires on Polyimide Substrates
    • Abstract: The successful fabrication of ultra‐thin films of CoFeB/Pt with strong perpendicular magnetic anisotropy and antiferromagnetic interfacial interlayer coupling on flexible polyimide substrates is demonstrated. Despite an increased surface roughness and defect density on the polyimide substrate, magnetic single layers of CoFeB still show sharp coercive switching. Magnetic Kerr imaging shows that the magnetization reversal is dominated by a greater density of nucleation sites than the identical film grown on Si. These layers maintain their magnetic characteristics down to a radius of curvature of 350 ± µm. Further, antiferromagnetically (AF) Ruderman‐Kittel‐Kasuya‐Yoshida (RKKY) coupled bilayers of CoFeB were fabricated which are robust under bending and the coupling strength is successfully modulated via interlayer engineering. Finally, a perpendicular synthetic antiferromagnetic (SAF) thin film grown on a polyimide substrate is patterned into straight 10 µm long nanowires down to 210 nm in width that displayed the robust switching characteristics of the thin film. These are extremely promising results for the fabrication of robust, flexible, magneto‐electronic, non‐volatile memory, logic, and sensor devices. Perpendicular magnetic anisotropy (PMA) thin films with interlayer exchange coupling are technologically relevant for the next generation of magnetic memory and logic devices. Despite the extreme sensitivity of the magnetic properties to substrate roughness conditions, PMA CoFeB single magnetic layers, and synthetic antiferromagnetic thin films and nanowires, are successfully fabricated on polyimide substrates, and are magnetically robust under bending.
      PubDate: 2016-05-11T00:56:28.838856-05:
      DOI: 10.1002/adfm.201505138
       
  • Elastic Carbon Nanotube Aerogel Meets Tellurium Nanowires: A Binder‐
           and Collector‐Free Electrode for Li‐Te Batteries
    • Abstract: Rechargeable Li batteries based on group VIA element cathodes, such as tellurium, are emerging due to their capability to provide equivalent theoretical volumetric capacity density to O and S, as well as an improved activity to react with Li. Herein, bifunctional and elastic carbon nanotube (CNT) aerogel is fabricated to combine with Te nanowires, yielding two types of binder/collector‐free Te cathodes to assemble Li‐Te batteries. The CNTs with high electronic conductivity and hollow porous structure enable stable electric contact and fast transportation of Li+, while trapping Te and Li2Te in its network, triggering fast and stable Li‐Te electrochemistry. Both cathodes are also provided with fine compressibility, helping to buffer their volume changes during lithiation/delithiation and improving electrode integrity. Both cathodes deliver high specific capacity, fine cycling stability, and favorable high‐rate capability, proving their competence in building high‐energy rechargeable Li‐ion batteries. Two types of binder/collector‐free Te cathodes (TeNW/CNT cathode and Te@CNT cathode) are constructed from a bifunctional and elastic carbon nanotube aerogel and Te nanowires, and are used for high‐energy Li‐Te batteries. The Te@CNT cathode exhibits excellent high‐rate stability in an extended cycling test at 1 C.
      PubDate: 2016-05-11T00:56:19.614215-05:
      DOI: 10.1002/adfm.201600640
       
  • Light‐Responsive, Singlet Oxygen‐Triggered On‐Demand
           Drug Release from Photosensitizer‐Doped Mesoporous Silica Nanorods
           for Cancer Combination Therapy
    • Authors: Guangbao Yang; Xiaoqi Sun, Jingjing Liu, Liangzhu Feng, Zhuang Liu
      Abstract: Smart drug delivery systems with on‐demand drug release capability are rather attractive to realize highly specific cancer treatment. Herein, a novel light‐responsive drug delivery platform based on photosensitizer chlorin e6 (Ce6) doped mesoporous silica nanorods (CMSNRs) is developed for on‐demand light‐triggered drug release. In this design, CMSNRs are coated with bovine serum albumin (BSA) via a singlet oxygen (SO)‐sensitive bis‐(alkylthio)alkene (BATA) linker, and then modified with polyethylene glycol (PEG). The obtained CMSNR‐BATA‐BSA‐PEG, namely CMSNR‐B‐PEG, could act as a drug delivery carrier to load with either small drug molecules such as doxorubicin (DOX), or larger macromolecules such as cis‐Pt (IV) pre‐drug conjugated third generation dendrimer (G3‐Pt), both of which are sealed inside the mesoporous structure of nanorods by BSA coating. Upon 660 nm light irradiation with a rather low power density, CMSNRs with intrinsic Ce6 doping would generate SO to cleave BATA linker, inducing detachment of BSA‐PEG from the nanorod surface and thus triggering release of loaded DOX or G3‐Pt. As evidenced by both in vitro and in vivo experiments, such CMSNR‐B‐PEG with either DOX or G3‐Pt loading offers remarkable synergistic therapeutic effects in cancer treatment, owing to the on‐demand release of therapeutics specifically in the tumor under light irradiation. CMSNR‐B‐PEG acts as a drug delivery carrier to load with either small drug molecules or larger macromolecules. This work develops a novel approach to engineer smart on‐demand drug delivery/release systems responsive to long‐wavelength light with a rather low optical power, interesting not only for anti‐cancer chemotherapy, but also potentially for gene therapy or immunotherapy toward cancer or other diseases.
      PubDate: 2016-05-11T00:56:14.340948-05:
      DOI: 10.1002/adfm.201600722
       
  • Rational Design of Highly Porous SnO2 Nanotubes Functionalized with
           Biomimetic Nanocatalysts for Direct Observation of Simulated Diabetes
    • Abstract: 1D metal‐oxide nanotube (NT) structures have attracted considerable attention for applications in chemical sensors due to their high surface area and unique chemical and physical properties. Moreover, bimodal pores, i.e., meso‐ and macro‐sized pores, which are formed on the shell of NTs, can further facilitate gas penetration into the sensing layers, leading to much improved sensing properties. However, thin‐walled NTs with bimodal pore distribution have been rarely fabricated due to the limitations of synthetic methods. Here, Ostwald ripening‐driven electrospinning combined with sacrificial templating route using polystyrene (PS) colloid and bioinspired protein is firstly proposed for producing both bi‐modal pores and catalyst‐loaded thin‐walled SnO2 NTs. Homogeneous catalyst loading on porous SnO2 NTs is achieved by the protein cage that contains catalysts and PS colloids and protein shells are thermally decomposed during calcination of electrospun fibers, resulting in the creation of dual‐sized pores on NTs. Pt catalyst decorated porous SnO2 NTs (Pt‐PS_SnO2 NTs) show exceptionally high acetone gas response, superior selectivity against other interfering gases, and very low limit of detection (10 ppb) to simulated diabetic acetone molecules. More importantly, sensor arrays assembled with developed porous SnO2 NTs enable the direct distinction between the simulated diabetic breath and normal breath from healthy people. Highly mesoporous SnO2 nanotubes (NTs) functionalized with large pores and bioinspired catalysts (Pt‐PS_SnO2 NTs) are simply synthesized as an ideal nanostructure of sensing layers by using biotemplating route and diffusion of SnO2 effect. Pt‐PS_SnO2 NTs exhibit dramatically enhanced acetone sensing performance; especially, they can clearly distinguish the exhaled breath of healthy people and diabetics.
      PubDate: 2016-05-09T08:27:28.28791-05:0
      DOI: 10.1002/adfm.201600797
       
  • Enhancing the Sensitivity of Percolative Graphene Films for Flexible and
           Transparent Pressure Sensor Arrays
    • Authors: Zhuo Chen; Tian Ming, Mahomed Mehdi Goulamaly, Heming Yao, Daniel Nezich, Marek Hempel, Mario Hofmann, Jing Kong
      Abstract: Flexible and transparent pressure sensor arrays can find applications in many places such as touch panels, artificial skin, or human motion detection. However, conventional strain gauges are rigid and opaque and are not suitable for such applications. Graphene‐based percolative strain gauges can overcome these challenges but currently are still in the infancy of their development. In this work, the performance of graphene‐based percolative strain gauges is investigated and guidelines to improve the durability and sensitivity of graphene films as sensing elements are developed. It is found that the gauge factor depends on the initial resistance of the graphene film. For the same film resistance, it is found that graphene flake size and film morphology also play a role in determining the gauge factor. Increasing the flake–flake resistance through assembly of surfactant molecules between graphene flakes provides an additional route to enhance the gauge factor. Furthermore, encapsulating the percolative film in micrometer‐thin Poly(methyl methacrylate) does not disrupt the sensing process but significantly improves the sensor's durability. Finally, thus enhanced graphene strain gauges are integrated into flexible and transparent pressure sensor arrays that exhibit high reproducibility and sensitivity. The performance of graphene‐based percolative strain gauges is investigated and guidelines to improve the durability and sensitivity of graphene films as sensing elements are developed. The enhanced graphene strain gauges are encapsulated in micrometer‐thin Poly(methyl methacrylate) (PMMA) and integrated into flexible and transparent pressure sensor arrays that exhibit high reproducibility and sensitivity.
      PubDate: 2016-05-09T08:13:47.72761-05:0
      DOI: 10.1002/adfm.201503674
       
  • Thermoresponsive Nanogel‐Encapsulated PEDOT and HSP70 Inhibitor for
           Improving the Depth of the Photothermal Therapeutic Effect
    • Authors: Dongdong Liu; Liyi Ma, Yanxin An, Yu Li, Yuxin Liu, Lu Wang, Jin Guo, Jianhua Wang, Jing Zhou
      Abstract: Photothermal therapy (PTT), a new, noninvasive treatment measure, has recently drawn much attention. However, due to the limited penetration depth of near‐infrared (NIR) light, PTT is focused on treating superficial tumors. Improving the depth of the therapeutic effect is a bottleneck for successful PTT. To solve this problem, a new kind of nanoplatform (Nanogel+phenylethynesulfonamide (PES)) is fabricated by using a thermo‐responsive polymer shell (poly(N‐isopropylacrylamide‐co‐acrylic acid) to encapsulate 2‐PES, an effective heat shock protein 70 (HSP70) inhibitor, and poly(3,4‐ethylenedioxythiophene), a widely used photothermal coupling agent. Upon NIR irradiation, PES can be released from the Nanogel+PES when a thermo‐responsive phase transition occurs, which could restrain the function of HSP70 and reduces the cells' endurance to heat. In this way, a better therapeutic effect on deeper tissues is achieved with a relatively small rise in temperature. Therefore, with the advantages of the thermo‐responsive photothermal effect, coupled with the inhibition of HSP70, and minimal cytotoxicity, the Nanogel+PES appears to be a promising photothermal agent that can improve the depth of the PTT effect. A new kind of thermo‐responsive photothermal agent (Nanogel+phenylethynesulfonamide (PES)) is fabricated by using (poly(N‐isopropylacrylamide‐co‐acrylic acid) (a thermo‐responsive polymer shell) to encapsulate PES (an effective heat shock protein 70 (HSP70) inhibitor) and poly(3,4‐ethylenedioxythiophene) (a widely used photothermal agent). As a result, PES can be released upon irradiation and interferes with HSP70, and results in improving the depth of photothermal therapeutic effect.
      PubDate: 2016-05-09T08:13:42.965123-05:
      DOI: 10.1002/adfm.201600031
       
  • Effect of Donor Molecular Structure and Gate Dielectric on
           Charge‐Transporting Characteristics for Isoindigo‐Based
           Donor–Acceptor Conjugated Polymers
    • Abstract: This study investigates the effect of the molecular structure of three different donor units, naphthalene (Np), bithiophene (BT), and thiophene–vinylene–thiophene (TVT), in isoindigo (IIG)‐based donor –acceptor conjugated polymers (PIIG‐Np, PIIG‐BT and PIIG‐TVT) on the charge carrier mobility of organic field‐effect transistors (OFETs). The charge transport properties of three different IIG‐based polymers strongly depend on donor units. PIIG–BT OFETs showed 50 times higher hole mobility (0.63 cm2 V−1 s−1) than PIIG–TVT and PIIG–Np ones of ≈ 0.01 cm2 V−1 s−1 with CYTOP dielectric though the BT units have less planarity than the TVT and Np units. The reasons for the different mobility in IIG‐based polymers are studied by analyzing the energy structure by absorption spectra, calculating transport levels by density functional theory, investigating the in‐ and out‐of‐plane crystallinity of thin film by grazing‐incidence wide‐angle X‐ray scattering, and extracting key transport parameters via low‐temperature measurements. By combining theoretical, optical, electrical, and structural analyses, this study finds that the large difference in OFET mobility mainly originates from the transport disorders determined by the different microcrystal structure, rather than the intrinsic transport properties in isolated chains for different polymers. The effect of the molecular structure of three different donor units, naphthalene (Np), bithiophene (BT), and thiophene–vinylene–thiophene (TVT), in isoindigo (IIG)‐based donor–acceptor conjugated polymers on the charge carrier mobility of organic field‐effect transistors is investigated. PIIG–BT OFETs shows 50 times higher hole mobility (0.63 cm2 V−1 s−1) than IIG–TVT and IIG–Np ones of ≈ 0.01 cm2 V−1 s−1.
      PubDate: 2016-05-09T08:13:11.778985-05:
      DOI: 10.1002/adfm.201504908
       
  • Surface Structural Transition Induced by Gradient Polyanion‐Doping
           in Li‐Rich Layered Oxides: Implications for Enhanced Electrochemical
           Performance
    • Authors: Ying Zhao; Jiatu Liu, Shuangbao Wang, Ran Ji, Qingbing Xia, Zhengping Ding, Weifeng Wei, Yong Liu, Peng Wang, Douglas G. Ivey
      Abstract: Lithium‐rich layered oxides (LLOs) exhibit great potential as high‐capacity cathode materials for lithium‐ion batteries, but usually suffer from capacity/voltage fade during electrochemical cycling. Herein, a gradient polyanion‐doping strategy is developed to initiate surface structural transition to form a spinel‐like surface nanolayer and a polyanion‐doped layered core material in LLOs simultaneously. This strategy integrates the advantages of both bulk doping and surface modification as the oxygen close‐packed structure of LLOs is stabilized by polyanion doping, and the LLO cathodes are protected from steady corrosion induced by electrolytes. A LLO material modified with 5 at% phosphate (5%P@LLO) shows a high reversible discharge capacity of ≈300 mAh g−1 at 0.1 C, excellent cycling stability with a capacity retention of 95% after 100 cycles, and enhanced electrode kinetics. This gradient doping strategy can be further extended to other polyanion‐doped LLO materials, such as borate and silicate polyanions. A gradient polyanion‐doping strategy associated with surface structural transition is developed to improve the electrochemical performance of Li‐rich layered oxide (LLO) cathodes. This strategy integrates the advantages of both bulk doping and surface modification as the oxygen close‐packed structure of LLOs is stabilized by polyanion doping, and the LLO cathodes are protected from steady corrosion induced by electrolytes.
      PubDate: 2016-05-09T08:12:15.729592-05:
      DOI: 10.1002/adfm.201600576
       
  • Capacitance Characterization of Elastomeric Dielectrics for Applications
           in Intrinsically Stretchable Thin Film Transistors
    • Abstract: Stretchable electronics exhibit unique mechanical properties to expand the applications areas of conventional electronics based on rigid wafers. Intrinsically stretchable thin film transistor is an essential component for functional stretchable electronics, which presents a great opportunity to develop mechanically compliant electronic materials. Certain elastomers have been recently adopted as the gate dielectrics, but their dielectric properties have not been thoroughly investigated for such applications. Here, a charging measurement technique with a resistor–capacitor circuit is proposed to quantify the capacitance of the dielectric layers based on elastomers. As compared with conventional methods, the technique serves as a universal approach to extract the capacitance of various elastomers under static conditions, irrespective of the charging mechanisms. This technique also offers a facile approach to reliably quantify the mobility of thin film transistors based on elastomeric dielectrics, paving the way to utilize this class of dielectrics in the development of intrinsically stretchable transistors. A charging measurement technique is introduced as a universal approach to quantify the capacitance of elastomeric dielectrics. It reveals elastomers may either behave as conventional rigid polymer dielectrics or solid‐state electrolyte, with distinctive capacitance values and scaling relations. The development allows the mobility values of corresponding thin film transistors to be accurately determined, which is essential for the development of instrinsically stretchable transistors.
      PubDate: 2016-05-09T08:11:21.517365-05:
      DOI: 10.1002/adfm.201600612
       
  • Fibrillar Elastomeric Micropatterns Create Tunable Adhesion Even to Rough
           Surfaces
    • Abstract: Biologically inspired, fibrillar dry adhesives continue to attract much attention as they are instrumental for emerging applications and technologies. To date, the adhesion of micropatterned gecko‐inspired surfaces has predominantly been tested on stiff, smooth substrates. However, all natural and almost all artificial surfaces have roughnesses on one or more different length scales. In the present approach, micropillar‐patterned PDMS surfaces with superior adhesion to glass substrates with different roughnesses are designed and analyzed. The results reveal for the first time adhesive and nonadhesive states depending on the micropillar geometry relative to the surface roughness profile. The data obtained further demonstrate that, in the adhesive regime, fibrillar gecko‐inspired adhesive structures can be used with advantage on rough surfaces; this finding may open up new applications in the fields of robotics, biomedicine, and space exploration. The influence of surface roughness on the adhesion strength of elastomeric pillar arrays is systematically studied. The results reveal novel adhesive and non‐adhesive states depending on the micropillar geometry relative to the surface roughness profile.
      PubDate: 2016-05-09T08:11:12.642031-05:
      DOI: 10.1002/adfm.201600652
       
  • Fe3O4‐Decorated Co9S8 Nanoparticles In Situ Grown on Reduced
           Graphene Oxide: A New and Efficient Electrocatalyst for Oxygen Evolution
           Reaction
    • Authors: Jing Yang; Guoxing Zhu, Yuanjun Liu, Jiexiang Xia, Zhenyuan Ji, Xiaoping Shen, Shikui Wu
      Abstract: Cobalt sulfide materials have attracted enormous interest as low‐cost alternatives to noble‐metal catalysts capable of catalyzing both oxygen reduction and oxygen evolution reactions. Although recent advances have been achieved in the development of various cobalt sulfide composites to expedite their oxygen reduction reaction properties, to improve their poor oxygen evolution reaction (OER) activity is still challenging, which significantly limits their utilization. Here, the synthesis of Fe3O4‐decorated Co9S8 nanoparticles in situ grown on a reduced graphene oxide surface (Fe3O4@Co9S8/rGO) and the use of it as a remarkably active and stable OER catalyst are first reported. Loading of Fe3O4 on cobalt sulfide induces the formation of pure phase Co9S8 and highly improves the catalytic activity for OER. The composite exhibits superior OER performance with a small overpotential of 0.34 V at the current density of 10 mA cm−2 and high stability. It is believed that the electron transfer trend from Fe species to Co9S8 promotes the breaking of the Co–O bond in the stable configuration (Co–O–O superoxo group), attributing to the excellent catalytic activity. This development offers a new and effective cobalt sulfide‐based oxygen evolution electrocatalysts to replace the expensive commercial catalysts such as RuO2 or IrO2. A new Fe3O4@Co9S8/rGO composite is developed as a high‐performance oxygen evolution catalyst, which provides a small overpotential of 0.34 V for 10 mA cm−2 current density. It is proposed that the electron transfer trend from Fe species to Co9S8 promotes the breaking of the CoO bond in the stable configuration (CoOO superoxo group), attributing to the excellent catalytic activity.
      PubDate: 2016-05-09T08:10:56.478088-05:
      DOI: 10.1002/adfm.201600674
       
  • Layered Orthorhombic Nb2O5@Nb4C3Tx and TiO2@Ti3C2Tx Hierarchical
           Composites for High Performance Li‐ion Batteries
    • Abstract: Engineering electrode nanostructures is critical in developing high‐capacity, fast rate‐response, and safe Li‐ion batteries. This study demonstrates the synthesis of orthorhombic Nb2O5@Nb4C3Tx (or @Nb2CTx) hierarchical composites via a one‐step oxidation —in flowing CO2 at 850 °C —of 2D Nb4C3Tx (or Nb2CTx) MXene. The composites possess a layered architecture with orthorhombic Nb2O5 nanoparticles decorated uniformly on the surface of the MXene flakes and interconnected by disordered carbon. The composites have a capacity of 208 mAh g−1 at a rate of 50 mA g−1 (0.25 C) in 1–3 V versus Li+/Li, and retain 94% of the specific capacity with 100% Coulombic efficiency after 400 cycles. The good electrochemical performances could be attributed to three synergistic effects: (1) the high conductivity of the interior, unoxidized Nb4C3Tx layers, (2) the fast rate response and high capacity of the external Nb2O5 nanoparticles, and (3) the electron “bridge” effects of the disordered carbon. This oxidation method was successfully extended to Ti3C2Tx and Nb2CTx MXenes to prepare corresponding composites with similar hierarchical structures. Since this is an early report on producing this structure, there is much room to push the boundaries further and achieve better electrochemical performance. The oxidation of Nb4C3Tx MXene in CO2 results in a hierarchical T‐Nb2O5@Nb4C3Tx layered composite, that combines the high capacity of the external orthorhombic T‐Nb2O5, coupled with the high electrical conductivity of the interior unoxidized Nb4C3Tx and the electron bridge effect of the disordered carbon. This composite exhibits high capacity at high rate when used as Li‐ion battery anode.
      PubDate: 2016-05-09T08:10:20.64264-05:0
      DOI: 10.1002/adfm.201600682
       
  • Physical Mechanisms behind the Field‐Cycling Behavior of
           HfO2‐Based Ferroelectric Capacitors
    • Abstract: Novel hafnium oxide (HfO2)‐based ferroelectrics reveal full scalability and complementary metal oxide semiconductor integratability compared to perovskite‐based ferroelectrics that are currently used in nonvolatile ferroelectric random access memories (FeRAMs). Within the lifetime of the device, two main regimes of wake‐up and fatigue can be identified. Up to now, the mechanisms behind these two device stages have not been revealed. Thus, the main scope of this study is an identification of the root cause for the increase of the remnant polarization during the wake‐up phase and subsequent polarization degradation with further cycling. Combining the comprehensive ferroelectric switching current experiments, Preisach density analysis, and transmission electron microscopy (TEM) study with compact and Technology Computer Aided Design (TCAD) modeling, it has been found out that during the wake‐up of the device no new defects are generated but the existing defects redistribute within the device. Furthermore, vacancy diffusion has been identified as the main cause for the phase transformation and consequent increase of the remnant polarization. Utilizing trap density spectroscopy for examining defect evolution with cycling of the device together with modeling of the degradation results in an understanding of the main mechanisms behind the evolution of the ferroelectric response. The impact of the complex interplay of mobile defects, charge trapping, and phase transitions on the macroscopic ferroelectric switching behavior of a doped HfO2‐based dielectric is discussed. The interaction of the oxygen vacancy intergrain diffusion and the observed phase transitions is unambiguously linked with a built‐in bias removal and opening of the hysteresis within the doped HfO2 thin films.
      PubDate: 2016-05-06T13:05:27.742494-05:
      DOI: 10.1002/adfm.201600590
       
  • Engineering Substrate Interactions for High Luminescence Efficiency of
           Transition‐Metal Dichalcogenide Monolayers
    • Abstract: It is demonstrated that the luminescence efficiency of monolayers composed of MoS2, WS2, and WSe2 is significantly limited by the substrate and can be improved by orders of magnitude through substrate engineering. The substrate affects the efficiency mainly through doping the monolayers and facilitating defect‐assisted nonradiative exciton recombinations, while the other substrate effects including straining and dielectric screening play minor roles. The doping may come from the substrate and substrate‐borne water moisture, the latter of which is much stronger than the former for MoS2 and WS2 but negligible for WSe2. Using proper substrates such as mica or hexagonal boron nitride can substantially mitigate the doping effect. The defect‐assisted recombination depends on the interaction between the defect in the monolayer and the substrate. Suspended monolayers, in which the substrate effects are eliminated, may have efficiency up to 40% at room temperatures. The result provides useful guidance for the rational design of atomic‐scale light emission devices. Luminescence efficiency in transition metal dichalcogenide monolayers can be improved by orders of magnitude through engineering the interaction with substrates. The luminescence efficiency of the monolayers is mainly affected through doping and facilitating nonradiative exciton recombination. Since the doping effect significantly depends on the kind of substrate, choosing the right type of substrates is a crucial step toward maximizing efficiency.
      PubDate: 2016-05-06T00:51:47.632743-05:
      DOI: 10.1002/adfm.201600418
       
  • Single‐Walled Carbon Nanotube Networks: The Influence of Individual
           Tube–Tube Contacts on the Large‐Scale Conductivity of Polymer
           Composites
    • Abstract: Over two decades after carbon nanotubes started to attract interest for their seemingly huge prospects, their electrical properties are far from being used to the maximum potential. Composite materials based on carbon nanotubes still have conductivities several orders of magnitude below those of the tubes themselves. This study aims at understanding the reason for these limitations and the possibilities to overcome them. Based on and validated by real single‐walled carbon nanotube (SWCNT) networks, a simple model is developed, which can bridge the gap between macroscale and nanoscale down to individual tube–tube contacts. The model is used to calculate the electrical properties of the SWCNT networks, both as‐prepared and impregnated with an epoxy‐amine polymer. The experimental results show that the polymer has a small effect on the large‐scale network resistance. From the model results it is concluded that the main contribution to the conductivity of the network results from direct contacts, and that in their presence tunneling contacts contribute insignificantly to the conductivity. Preparing highly conductive polymer composites is only possible if the number of direct, low‐resistance contacts in the network is sufficiently large and therefore these direct contacts play the key role. Developed from and validated by experiments on single‐walled carbon nanotube networks, a simple model shows that direct, low‐resistance contacts are mainly responsible for the conductivity of a polymer composite, while in their presence tunneling contacts contribute insignificantly. Therefore, preparing polymer composites as conductive as their equivalent pure carbon nanotube networks is realistic, but only if direct contacts can be ensured.
      PubDate: 2016-05-03T08:36:11.813116-05:
      DOI: 10.1002/adfm.201600435
       
  • Electric Field Tunable Interlayer Relaxation Process and Interlayer
           Coupling in WSe2/Graphene Heterostructures
    • Abstract: Transition metal dichalcogenides van der Waals (vdWs) heterostructures present fascinating optical and electronic phenomena, and bear tremendous significance for electronic and optoelectronic applications. As the significant merits in vdWs heterostructures, the interlayer relaxation of excitons and interlayer coupling at the heterointerface reflect the dynamic behavior of charge transfer and the coupled electronic/structural characteristics, respectively, which may give rise to new physics induced by quantum coupling. In this work, upon tuning the photoluminescence (PL) properties of WSe2/graphene and WSe2/MoS2/graphene heterostructures by virtue of electric field, it is demonstrated that the interlayer relaxation of excitons at the heterointerface in WSe2/graphene, which is even stronger than that in MoS2/graphene and WSe2/MoS2 , plays a dominant role in PL tuning in WSe2/graphene, while the carrier population in WSe2 induced by electric field has a minor contribution. In addition, it is discovered that the interlayer coupling between monolayer WSe2 and graphene is enhanced under high electric field, which breaks the momentum conservation of first order Raman‐allowed phonons in graphene, yielding the enhanced Raman scattering of defects in graphene. The interplay between electric field and vdWs heterostructures may provide versatile approaches to tune the intrinsic electronic and optical properties of the heterostructures. It is demonstrated that the photoluminescence (PL) properties and interlayer coupling in WSe2/graphene heterostructures can be tuned by an electric field. PL intensity in monolayer WSe2/graphene is modulated 40 times. Additionally, it is discovered that the interlayer coupling between monolayer WSe2 and graphene is enhanced under high electric field, inducing the enhanced Raman scattering of defects in graphene.
      PubDate: 2016-05-02T07:57:15.769372-05:
      DOI: 10.1002/adfm.201505412
       
  • Benchtop Fluorination of Fluorescent Nanodiamonds on a Preparative Scale:
           Toward Unusually Hydrophilic Bright Particles
    • Abstract: Fluorination of diamonds modulates their optical and electromagnetic properties and creates surfaces with increased hydrophobicity. In addition, fluorination of diamonds and nanodiamonds has been recently shown to stabilize fluorescent nitrogen‐vacancy centers, which can serve as extremely sensitive single atomic defects in a vast range of sensing applications from quantum physics to high‐resolution biological imaging. Traditionally, fluorination of carbon nanomaterials has been achieved using harsh and complex experimental conditions, creating hydrophobic interfaces with difficult dispersibility in aqueous environments. Here, a mild benchtop approach to nanodiamond fluorination is described using selective Ag+‐catalyzed radical substitution of surface carboxyls for fluorine. In contrast to other approaches, this high‐yielding procedure does not etch diamond carbons and produces a highly hydrophilic interface with mixed C−F and C−OH termination. This dual functionalization of nanodiamonds suppresses detrimental hydrophobic interactions that would lead to colloidal destabilization of nanodiamonds. It is also demonstrated that even a relatively low surface density of fluorine contributes to stabilization of negatively charged nitrogen‐vacancy centers and boosts their fluorescence. The simultaneous control of the surface hydrophilicity and the fluorescence of nitrogen‐vacancy centers is an important issue enabling direct application of fluorescent nanodiamonds as nanosensors for quantum optical and magnetometry measurements operated in biological environment. Hydrophilic fluorinated nanodiamonds with stabilized fluorescence from nitrogen‐vacancy centres are presented. A high‐yielding decarboxylative fluorination performed in acqueous environment creates a unique mixed C–F/C–OH surface. In contrast to other fluorine‐based diamond terminations, it retains the colloidal stability of nanodiamonds and boosts the fluorescence of NV− centers at the same time. This nonetching one‐step approach can be easily performed on the benchtop without special safety precautions.
      PubDate: 2016-05-02T07:57:08.833954-05:
      DOI: 10.1002/adfm.201504857
       
  • Contactless and Rapid Discrimination of Improvised Explosives Realized by
           Mn2+ Doping Tailored ZnS Nanocrystals
    • Authors: Zhaofeng Wu; Chaoyu Zhou, Baiyi Zu, Yushu Li, Xincun Dou
      Abstract: In order to sensitively, selectively, and rapidly detect the constituents relevant to improvised explosive devices (IEDs), the sensing properties of ZnS nanocrystals (NCs) are regulated by tailoring the doping level of Mn2+. The responses of the sensors fabricated by ZnS NCs with different Mn‐doping levels (Mn:ZnS) toward the constituents, such as sulphur powder and black powder, generally increases first and then decreases with the increase of the concentration of doped Mn2+, and reaches the climate with an atomic ratio of 2.23% at room temperature. The sensory array based on eight sensors of Mn:ZnS NCs can realize the detection of two typical military explosives and six constituents relevant to IEDs within 7 s and can recover in 19 s. Furthermore, the fingerprinting of the constituents is achieved by pattern recognizing the inherent kinetics and thermodynamics of interaction between the sensory array and the constituents. Thus, a simple chemiresistive sensing strategy based on semiconductor NCs which can rapidly, supersensitively, and discriminatively detect the constituents relevant to IEDs is explored for the first time. A chemiresistive sensing scheme to sensitively and rapidly detect the vapors of the constituents relevant to improvised explosive devices (IEDs) at room temperature is achieved by tailoring the sensing properties of ZnS nanocrystals. The resulting differential identification capability toward explosives makes the on‐the‐spot detection of IEDs possible.
      PubDate: 2016-05-02T07:57:04.878563-05:
      DOI: 10.1002/adfm.201600592
       
  • Theranostic Oxygen Reactive Polymers for Treatment of Traumatic Brain
           Injury
    • Authors: Julia Xu; Menko Ypma, Peter A. Chiarelli, Joshua Park, Richard G. Ellenbogen, Patrick S. Stayton, Pierre D. Mourad, Donghoon Lee, Anthony J. Convertine, Forrest M. Kievit
      Abstract: Traumatic brain injury (TBI) is the leading cause of disability and death in children and adults under 45, with approximately ten million new cases per year worldwide. Significant progress has been made in understanding the complex pathophysiological response to TBI; however, reducing the damage associated with the reactive oxygen species (ROS)‐dependent secondary phase of the injury remains a substantial challenge. The development of an image‐guided, Gd‐conjugated, oxygen reactive polymer (ORP) to reduce ROS levels in damaged brain tissue is reported. ORP effectively sequesters ROS while remaining biocompatible even at elevated concentrations. ORP is retained in damaged brains of controlled cortical impact (CCI) mouse models of TBI for over 24 h when injected intravenously immediately and up to 3 h post‐CCI. The polymer reduces neurodegeneration tenfold and gliosis twofold in these mouse models. ORP shows initial promise as an effective therapy for TBI and helps provide a better understanding of nanomaterial interaction with damaged brain. Oxygen reactive polymers (ORP) can accumulate in damaged brain in mouse models of traumatic brain injury (TBI) and be visualized using magnetic resonance imaging. Accumulation and retention of ORP is accompanied by reduced neurodegeneration and gliosis, indicators of TBI severity. ORP should help further the understanding of nanomaterial interaction with TBI and hopefully leads to improved outcome for brain injury patients.
      PubDate: 2016-05-02T07:45:38.048653-05:
      DOI: 10.1002/adfm.201504416
       
  • A Versatile Self‐Organization Printing Method for Simplified Tandem
           Organic Photovoltaics
    • Authors: Seok Kim; Hongkyu Kang, Soonil Hong, Jinho Lee, Seongyu Lee, Byoungwook Park, Junghwan Kim, Kwanghee Lee
      Abstract: Despite recent dramatic enhancements in power conversion efficiencies (PCEs) resulting in values over 10%, the manufacturing of tandem organic solar cells (OSCs) via current printing technologies is subject to tremendous challenges. Existing complicated tandem structures consisting of six or more component layers have been a major obstacle that significantly increases the complexity of printing processes and substantially sacrifices the PCE for printed devices. Here, an innovative printing method is reported that simplifies the fabrication process of the tandem OSCs. By developing a new printing technique using a nanocomposites containing interfacial and photoactive materials, a simultaneously printed bilayer of consisting of interfacial and photoactive layers, achieved through vertical self‐organization, is successfully demonstrated, resulting in tandem OSCs with only four printed layers. Moreover, by rigorously controlling the molecular weight of the interfacial materials, the self‐assembly characteristics are improved and an efficient tandem OSC is yielded with a PCE of 9.1% achieved in printed layers. Efficient and simplified tandem organic solar cells are demonstrated through a new self‐assembly printing technique using a spontaneous vertical phase separation. A bilayer of interfacial and photoactive layers is simultaneously printed by improving vertical self‐organization characteristics. A high tandem efficiency of 9.1% is obtained with a four‐layer tandem structure.
      PubDate: 2016-04-30T01:30:05.707946-05:
      DOI: 10.1002/adfm.201505161
       
  • Lightweight Triboelectric Nanogenerator for Energy Harvesting and Sensing
           Tiny Mechanical Motion
    • Authors: Tao Li; Ying Xu, Magnus Willander, Fei Xing, Xia Cao, Ning Wang, Zhong Lin Wang
      Abstract: Triboelectric nanogenerators (TENGs) have shown exciting applications in mechanical energy harvesting and self‐powered sensing. Aiming at commercial applications, cost reduction and simplification of TENG structures are of great interest. In this work, a lightweight TENG based on the integration of polymer nanowires and a carbon sponge, which serves both as the substrate and an electrode, are reported. Because of the low density of the carbon sponge and the filmy nanowires, the device exhibits a total mass of less than 0.1 g for a volume of 12.5 cm3 and it produces a short‐circuit current of 6 μA, open‐circuit voltage of 75 V, and a maximum output power of 0.28 W kg−1 under light finger tapping. The device can linearly measure the acceleration at a detection limit down to 0.25 m s−2 and for a detection range from 0.25 m s−2 to 10.0 m s−2. A novel strategy to enhance the performance of triboelectric nanogenerators by combining a carbon material with nanowire films is proposed. The device has a mass less than 0.1 g and can harvest mechanical energy from light finger tapping. The determination limit of acceleration for such device was as low as 0.25 m s−2.
      PubDate: 2016-04-29T10:49:29.659809-05:
      DOI: 10.1002/adfm.201600279
       
  • Epitaxy of Layered Orthorhombic SnS–SnSxSe(1−x)
           Core–Shell Heterostructures with Anisotropic Photoresponse
    • Abstract: Vertical and in‐plane heterostructures based on van der Waals (vdW) crystals have drawn rapidly increasing attention owning to the extraordinary properties and significant application potential. However, current heterostructures are mainly limited to vdW crystals with a symmetrical hexagonal lattice, and the heterostructures made by asymmetric vdW crystals are rarely investigated at the moment. In this contribution, it is reported for the first time the synthesis of layered orthorhombic SnS–SnSxSe(1−x) core–shell heterostructures with well‐defined geometry via a two‐step thermal evaporation method. Structural characterization reveals that the heterostructures of SnS–SnSxSe(1−x) are in‐plane interconnected and vertically stacked, constructed by SnSxSe(1−x) shell heteroepitaxially growing on/around the pre‐synthesized SnS flake with an epitaxial relationship of (303)SnS//(033)SnSxSe(1−x), [010]SnS//[100]SnSxSe(1−x). On the basis of detailed morphology, structure and composition characterizations, a growth mechanism involving heteroepitaxial growth, atomic diffusion, as well as thermal thinning is proposed to illustrate the formation process of the heterostructures. In addition, a strong polarization‐dependent photoresponse is found on the device fabricated using the as‐prepared SnS−SnSxSe(1−x) core–shell heterostructure, enabling the potential use of the heterostructures as functional components for optoelectronic devices featured with anisotropy. Layered orthorhombic SnS–SnSxSe(1−x) core–shell heterostructures are successfully synthesized via an epitaxial growth method. Due to the structural characteristic of the components, the heterostructures are able to show a strong polarization‐dependent photoresponse, which will facilitate developing novel functional optoelectronic devices beyond conventional materials.
      PubDate: 2016-04-29T10:49:23.635556-05:
      DOI: 10.1002/adfm.201600699
       
  • Fully Transparent Nanocomposite Coating with an Amorphous Alumina Matrix
           and Exceptional Wear and Scratch Resistance
    • Abstract: This study presents a method for high temperature stabilization of amorphous alumina. The strain‐induced stabilization is obtained by dispersion of rigid globular polycarbosilane macromolecules within an alumina matrix. The alumina matrix remains amorphous even at 1200 °C. This study confirms the chemical composition of the coating with an advanced chemical depth‐profile analysis and shows its nanostructure by transmission electron microscopy. Based on this amorphous nanocomposite, a new facile and inexpensive coating for mechanical protection of glass surfaces is further developed. The nanocomposite coating is characterized by a full optical transparency and exceptional tribological characteristics. The wear resistance exceeds that of the current advanced ion‐exchanged boroaluminosilicate glass by a factor of 25–35 whereas its scratch resistance is exceeded by more than an order of magnitude. The strain‐induced high‐temperature stabilization of amorphous alumina is obtained by dispersion of rigid globular polycarbosilane macromolecules within the alumina matrix. This nanocomposite is a base for a new facile and inexpensive coating for mechanical protection of glass surfaces. The nanocomposite coating is characterized by a full optical transparency and exceptional tribological characteristics.
      PubDate: 2016-04-29T10:49:17.544239-05:
      DOI: 10.1002/adfm.201600213
       
  • The Effects of Electronic Impurities and Electron–Hole Recombination
           Dynamics on Large‐Grain Organic–Inorganic Perovskite
           Photovoltaic Efficiencies
    • Abstract: Hybrid organic‐inorganic perovskites have attracted considerable attention after promising developments in energy harvesting and other optoelectronic applications. However, further optimization will require a deeper understanding of the intrinsic photophysics of materials with relevant structural characteristics. Here, the dynamics of photoexcited charge carriers in large‐area grain organic‐inorganic perovskite thin films is investigated via confocal time‐resolved photoluminescence spectroscopy. It is found that the bimolecular recombination of free charges is the dominant decay mechanism at excitation densities relevant for photovoltaic applications. Bimolecular coefficients are found to be on the order of 10−9 cm3 s−1, comparable to typical direct‐gap semiconductors, yet significantly smaller than theoretically expected. It is also demonstrated that there is no degradation in carrier transport in these thin films due to electronic impurities. Suppressed electron–hole recombination and transport that is not limited by deep level defects provide a microscopic model for the superior performance of large‐area grain hybrid perovskites for photovoltaic applications. The local dynamics of photoexcited charge carriers in “large‐grain hybrid organic‐inorganic perovskites” is presented. Under illumination conditions relevant for photovoltaics, a suppressed recombination of free carriers is observed where electronic impurities play a negligible role in the overall kinetics. This study provides a microscopic model for low defect large‐grain hybrid perovskites where non‐Langevin recombination results in superior photovoltaic performance.
      PubDate: 2016-04-27T06:57:09.269182-05:
      DOI: 10.1002/adfm.201505324
       
  • Mussel‐Inspired Conductive Cryogel as Cardiac Tissue Patch to Repair
           Myocardial Infarction by Migration of Conductive Nanoparticles
    • Authors: Leyu Wang; Junzi Jiang, Wenxi Hua, Ali Darabi, Xiaoping Song, Chen Song, Wen Zhong, Malcolm M. Q. Xing, Xiaozhong Qiu
      Abstract: The engineered cardiac patch (ECP) is a promising strategy to repair infarct myocardium and restore the cardiac function. An ideal ECP should be able to mimic the primary attributes of native myocardium, which includes a high resilience, good cardiomyocyte adhesion, and synchronous contraction. Here, a mussel‐inspired dopamine crosslinker is used to integrate polypyrrole (Ppy) nanoparticles, gelatin‐methyacrylate, and poly(ethylene glycol) diacrylate into a cryogel form. The dopamine crosslinker and Ppy nanoparticles are coordinated to obtain optimal mechanical and superelastic properties for the ECP. The dopamine facilitates the uniform distribution of the Ppy nanoparticles, which migrate and fuse from the scaffold to the surface of the cardiomyocytes, revealing a potential mechanism for restoring infarct myocardium. The incorporated Ppy nanoparticles thus significantly enhance the functionalization of the cardiomyocytes, resulting in excellent synchronous contraction by increasing the expression of α‐actinin and CX‐43. Cardiomyocytes‐loaded ECP can improve the cardiac function in myocardial‐infarction (MI) affected rat models. The results show that the fractional shortening and ejection fraction are elevated by about 50% and that the infarct size is reduced by 42.6%. Collectively, this study highlights an effective cardiac patch based on mussel‐inspired conductive particle adhesion and a superelastic cryogel promising for the restoration of infarcted myocardium. An engineered cardiac patch (ECP) is shown for the effective in vivo repair of infarcted heart tissue. The ECP is based on a mussel‐inspired conductive cryogel incorporating a multifuntional dopamine crosslinker, gelatin, and polypyrrole nanoparticles. The hydrogel shows super‐elasticity and conductivity, which promotes the adhesion and migration of cardiomyocytes.
      PubDate: 2016-04-27T06:57:05.376369-05:
      DOI: 10.1002/adfm.201505372
       
  • Slippery Liquid‐Infused Porous Surfaces that Prevent Microbial
           Surface Fouling and Kill Non‐Adherent Pathogens in Surrounding
           Media: A Controlled Release Approach
    • Abstract: Many types of slippery liquid‐infused porous surfaces (‘SLIPS’) can resist adhesion and colonization by microorganisms. These ‘slippery’ materials thus offer approaches to prevent fouling on commercial and industrial surfaces. However, while SLIPS can prevent fouling on surfaces to which they are applied, they can currently do little to prevent the proliferation of non‐adherent organisms. Here, multi‐functional SLIPS are reported that address this issue and expand the potential utility of these materials. The approach is based on the release of antimicrobial agents from the porous matrices used to host the infused oil phases. It is demonstrated that SLIPS fabricated from nanoporous polymer multilayers can prevent colonization and biofilm formation by four common fungal and bacterial pathogens, and that the polymer and oil phases comprising these materials can be used to sustain the release of triclosan, a model antimicrobial agent, into surrounding media. This approach improves the inherent anti‐fouling properties of these materials and endows them with the ability to kill non‐adherent pathogens. This strategy has the potential to be general; the strategies and concepts reported here will enable the design of SLIPS with improved anti‐fouling properties and open the door to new applications of slippery liquid‐infused materials that host or release other active agents. Slippery liquid‐infused porous surfaces (SLIPS) that prevent colonization by microbial pathogens and also kill non‐adherent organisms in surrounding media are reported. The approach exploits the polymer and liquid phases in these materials to sustain the release of an antimicrobial agent. This approach improves the inherent anti‐fouling properties of SLIPS, is general in scope, and expands the potential utility of SLIPS in fundamental and applied contexts.
      PubDate: 2016-04-27T06:56:53.865035-05:
      DOI: 10.1002/adfm.201505522
       
  • Manipulation of Irradiative Defects at MnSe and ZnSe Dopant–Host
           Interface
    • Authors: Chunlei Wang; Jingkun Xu, Yanbin Wang, Shuhong Xu, Zhengqing Qi, Changgui Lu, Yiping Cui
      Abstract: In the past few decades, trap emission was always believed hardly manipulated to luminescent quantum dots (QDs). Actually, not all trap emissions are useless. This work shows that the interface between MnSe dopant and ZnSe host could be used for manipulating irradiative defects with a controllable manner. This study focuses on three basic challenges for manipulating interface defects, including (i) how to introduce irradiative defects at the dopant–host interface, (ii) how to control the intensity of the interface trap emission, and (iii) how to tune QD emission color via the interface trap emission. Finally, this study shows the application of dopant–host interface defects in ratiometric optical thermometry. The interface between MnSe dopant and ZnSe host can be used for manipulating irradiative defects with a controllable manner. This work focuses on the way to introduce irradiative defects at dopant–host interface, the method to control interface trap emission, and the method to tune the emission color of quantum dots by interface trap emission.
      PubDate: 2016-04-26T07:16:57.846498-05:
      DOI: 10.1002/adfm.201505172
       
  • All‐Inorganic Perovskite Nanocrystals for High‐Efficiency
           
    • Authors: Xiaoli Zhang; Bing Xu, Jinbao Zhang, Yuan Gao, Yuanjin Zheng, Kai Wang, Xiao Wei Sun
      Abstract: A dual‐phase all‐inorganic composite CsPbBr3‐CsPb2Br5 is developed and applied as the emitting layer in LEDs, which exhibited a maximum luminance of 3853 cd m–2, with current density (CE) of ≈8.98 cd A–1 and external quantum efficiency (EQE) of ≈2.21%, respectively. The parasite of secondary phase CsPb2Br5 nanoparticles on the cubic CsPbBr3 nanocrystals could enhance the current efficiency by reducing diffusion length of excitons on one side, and decrease the trap density in the band gap on the other side. In addition, the introduction of CsPb2Br5 nanoparticles could increase the ionic conductivity by reducing the barrier against the electronic and ionic transport, and improve emission lifetime by decreasing nonradiative energy transfer to the trap states via controlling the trap density. The dual‐phase all‐inorganic CsPbBr3‐CsPb2Br5 composite nanocrystals present a new route of perovskite material for advanced light emission applications. Dual‐phase CsPbBr3‐CsPb2Br5 composites for all‐inorganic perovskite light emitting diodes (LEDs) are fabricated, which exhibit significantly improved performance, representing a great increase in the CE and EQE, about 21‐ and 18‐fold improvement than that of the best reported CsPbBr3 LEDs. The dual‐phase all‐inorganic CsPbBr3‐CsPb2Br5 composite nanocrystals present a new route of perovskite material for advanced light emission applications.
      PubDate: 2016-04-26T07:16:53.425758-05:
      DOI: 10.1002/adfm.201600958
       
  • UV–Vis–Infrared Light Driven Thermocatalytic Activity of
           Octahedral Layered Birnessite Nanoflowers Enhanced by a Novel
           Photoactivation
    • Authors: Fang Liu; Min Zeng, Yuanzhi Li, Yi Yang, Mingyang Mao, Xiujian Zhao
      Abstract: Nanoflowers of octahedral layered birnessite (OL‐NF) were synthesized and characterized with a variety of techniques. Remarkably, OL‐NF exhibits a catalytic activity with a high efficiency for CO oxidation under irradiation of the full solar spectrum, visible‐infrared, or infrared light. This highly efficient catalytic activity under solar‐light irradiation originates from solar‐light‐driven thermocatalysis related to the efficient photothermal conversion and thermocatalytic activity of OL‐NF. A conceptually novel photoactivation effect is found to significantly improve the activity of the lattice oxygen of OL‐NF, thus considerably increasing the thermocatalytic activity of OL‐NF. A novel photoactivation effect is thoroughly investigated for nanoflowers of octahedral layered birnessite (OL‐NF). Their efficient catalytic activity for CO oxidation under full solar spectrum, visible‐infrared, and infrared light is shown. This originates from solar‐light‐driven thermocatalysis that is related to their efficient photothermal conversion and thermocatalytic activity.
      PubDate: 2016-04-26T07:16:31.21623-05:0
      DOI: 10.1002/adfm.201601046
       
  • Metallic Cobalt Nanoparticles Encapsulated in Nitrogen‐Enriched
           Graphene Shells: Its Bifunctional Electrocatalysis and Application in
           Zinc–Air Batteries
    • Authors: Min Zeng; Yiling Liu, Feipeng Zhao, Kaiqi Nie, Na Han, Xinxia Wang, Wenjing Huang, Xuening Song, Jun Zhong, Yanguang Li
      Abstract: There has been a continuous call for active, durable, and low‐cost electrocatalysts for a range of energy applications. Among many different nonprecious metal based candidates, transition metal nanoparticles encapsulated in graphene layers have gained increasing attention over recent years. In this study, it is demonstrated that metallic cobalt nanoparticles sheathed by multilayered nitrogen‐enriched graphene shells can be facilely prepared using cobalt‐containing Prussian blue colloids as the single precursor. These metallic cobalt cores can be readily leached out by HCl treatment, resulting in hollow graphene spheres. Products with or without acid leaching exhibit great bifunctional activities for electrocatalytic oxygen reduction and hydrogen evolution in both alkaline and acidic electrolytes. Most importantly, it is found that the removal of the metallic cores does not deteriorate but rather enhances the electrocatalytic performance. Based on this and other experimental observations, Co‐N‐C moieties are proposed as the catalytically active sites. At last, it is shown that these catalysts can be employed as the air catalyst of primary zinc–air batteries with excellent current density, power density, and operation durability. Encapsulating metallic cobalt nanoparticles by a nitrogen‐enriched graphene shell makes an excellent bifunctional electrocatalyst and zinc–air battery cathode material.
      PubDate: 2016-04-26T07:15:58.036325-05:
      DOI: 10.1002/adfm.201600636
       
  • Fully Solution‐Processed Small Molecule Semitransparent Solar Cells:
           Optimization of Transparent Cathode Architecture and Four Absorbing Layers
           
    • Abstract: Semitransparent solar cells (SSCs) can open photovoltaic applications in many commercial areas, such as power‐generating windows and building integrated photovoltaics. This study successfully demonstrates solution‐processed small molecule SSCs with a conventional configuration for the presently tested material systems, namely BDTT‐S‐TR:PC70BM, N(Ph‐2T‐DCN‐Et)3:PC70BM, SMPV1:PC70BM, and UU07:PC60BM. The top transparent cathode coated through solution processes employs a highly transparent silver nanowire as electrode together with a combination interface bilayer of zinc oxide nanoparticles (ZnO) and a perylene diimide derivative (PDINO). This ZnO/PDINO bilayer not only serves as an effective cathode buffer layer but also acts as a protective film on top of the active layer. With this integrated contribution, this study achieves a power conversion efficiency (PCE) of 3.62% for fully solution‐processed SSCs based on BDTT‐S‐TR system. Furthermore, the other three systems with various colors exhibited the PCEs close to 3% as expected from simulations, demonstrate the practicality and versatility of this printed semitransparent device architecture for small mole­cule systems. This work amplifies the potential of small molecule solar cells for window integration. Small molecule semitransparent solar cells are successfully demonstrated with conventional structure using a zinc oxide nanoparticles and a perylene diimide with N‐oxide as electron extraction bilayer and silver nanowire as the top transparent electrode.
      PubDate: 2016-04-26T07:15:28.970484-05:
      DOI: 10.1002/adfm.201505411
       
  • Explosive Raspberries: Controlled Magnetically Triggered Bursting of
           Microcapsules
    • Abstract: On‐demand and spatially controlled release of active components is crucial in several applications ranging from medicine to food and agriculture. Although many encapsulation approaches have been developed to address specific application‐related boundary conditions, microcapsule systems that enable quick and site‐specific release are still highly demanded. Here, a new design for a magnetically triggered release system consisting of an inductively heatable core covered by temperature‐sensitive bursting microcapsules is proposed. Release of the microcapsule content is achieved within a few seconds by a locally induced thermal shock without overheating the surrounding matrix. The bursting microcapsules are produced from monodisperse double emulsion templates made by microfluidics. The microcapsule shell structure is heterogeneous, consisting of a polymer particle network wetted by a liquid blowing agent and sealed by a polymeric skin. Steel particles (1 mm) are selected as an exemplary heat source because of their fast temperature increase through magnetic induced heating. Proof‐of‐concept microbursting experiments are performed to demonstrate the efficacy of the proposed raspberry design in achieving controlled local release using a magnetic trigger. In this study, it is shown that the system can be applied for the on‐demand setting of cementitious materials by externally triggering the release of a cement accelerator without undesired excessive heating of the matrix. A magnetically triggered release system consisting of a metal core covered by temperature‐sensitive bursting microcapsules is proposed for site‐specific on‐demand release of active compounds. In this raspberry architecture, fast release is achieved by a locally induced thermal shock without overheating the surrounding matrix. Proof‐of‐concept bursting experiments successfully demonstrate the efficacy of the proposed raspberry design.
      PubDate: 2016-04-25T15:04:01.236198-05:
      DOI: 10.1002/adfm.201504656
       
  • Flexible Transparent Reduced Graphene Oxide Sensor Coupled with Organic
           Dye Molecules for Rapid Dual‐Mode Ammonia Gas Detection
    • Abstract: Flexible chemical sensors utilizing chemically sensitive nanomaterials are of great interest for wearable sensing applications. However, obtaining high performance flexible chemical sensors with high sensitivity, fast response, transparency, stability, and workability at ambient conditions is still challenging. Herein, a newly designed flexible and transparent chemical sensor of reduced graphene oxide (R‐GO) coupled with organic dye molecules (bromophenol blue) is introduced. This device has promising properties such as high mechanical flexibility (>5000 bending cycles with a bending radius of 0.95 cm) and optical transparency (>60% in the visible region). Furthermore, stacking the water‐trapping dye layer on R‐GO enables a higher response as well as workability in a large relative humidity range (up to 80%), and dual‐mode detection capabilities of colorimetric and electrical sensing for NH3 gas (5–40 ppm). These advantageous attributes of the flexible and transparent R‐GO sensor coupled with organic dye molecules provide great potential for real‐time monitoring of toxic gas/vapor in future practical chemical sensing at room conditions in wearable electronics. A flexible, transparent, dual‐mode chemical sensing device based on reduced graphene oxide and an organic dye is developed for wearable sensing applications. Demonstrative measurements upon exposure to NH3 reveal a novel combination of two complimentary sensing modes of conductometry and colorimetry for practical wearable chemical sensors at ambient conditions. These devices are low‐cost and require minimal power usage.
      PubDate: 2016-04-25T15:03:47.128108-05:
      DOI: 10.1002/adfm.201505477
       
  • Size‐Induced Switching of Nanowire Growth Direction: a New Approach
           Toward Kinked Nanostructures
    • Authors: Youde Shen; Oleg I. Lebedev, Stuart Turner, Gustaaf Van Tendeloo, Xiaohui Song, Xuechao Yu, Qijie Wang, Hongyu Chen, Shadi A. Dayeh, Tom Wu
      Abstract: Exploring self‐assembled nanostructures with controllable architectures has been a central theme in nanoscience and nanotechnology because of the tantalizing perspective of directly integrating such bottom‐up nanostructures into functional devices. Here, the growth of kinked single‐crystal In2O3 nanostructures consisting of a nanocone base and a nanowire tip with an epitaxial and defect‐free transition is demonstrated for the first time. By tailoring the growth conditions, a reliable switching of the growth direction from [111] to [110] or [112] is observed when the Au catalyst nanoparticles at the apexes of the nanocones shrink below ≈100 nm. The natural formation of kinked nanoarchitectures at constant growth pressures is related to the size‐dependent free energy that changes for different orientations of the nanowires. The results suggest that the mechanism of forming such kinked nanocone–nanowire nanostructures in well‐controlled growth environment may be universal for a wide range of functional materials. Kinked nanocone–nanowire In2O3 nanostructures are fabricated via precisely controlling the nanowire growth directions. The reliable switching of growth direction from [111] to [110] and [112] at a critical nanowire radius of 100 nm is explained by the size‐dependent free energy of growing nanowires with different orientations, which represents a vital step toward constructing nanoarchitectures with tailored structural complexities.
      PubDate: 2016-04-25T15:03:41.0124-05:00
      DOI: 10.1002/adfm.201600142
       
  • Strategies for Volumetric Recovery of Large Scale Damage in Polymers
    • Authors: Brett P. Krull; Ryan C. R. Gergely, Windy A. Santa Cruz, Yelizaveta I. Fedonina, Jason F. Patrick, Scott R. White, Nancy R. Sottos
      Abstract: The maximum volume that can be restored after catastrophic damage in a newly developed regenerative polymer system is explored for various mixing, surface wetting, specimen configuration, and microvascular delivery conditions. A two‐stage healing agent is implemented to overcome limitations imposed by surface tension and gravity on liquid retention within a damage volume. The healing agent is formulated as a two‐part system in which the two reagent solutions are delivered to a through‐thickness, cylindrical defect geometry by parallel microvascular channels in thin epoxy sheets. Mixing occurs as the solutions enter the damage region, inducing gelation to initiate an accretive deposition process that enables large damage volume regeneration. The progression of the damage recovery process is tracked using optical and fluorescent imaging, and the mixing efficiency is analyzed. Complete recovery of gaps spanning 11.2 mm in diameter (98 mm2) is achieved under optimal conditions. The maximum volume recovery achievable by two‐stage healing chemistry is investigated for various mixing, surface wetting, specimen configuration, and microvascular delivery conditions. Gelation enables the healing agents to overcome the influence of gravity and surface tension to regenerate cylindrical damage volumes. Complete material recovery is achieved for damage regions ranging up to 11.2 mm in diameter, an increase of 197% over non‐gelling control fluids.
      PubDate: 2016-04-25T15:03:34.035407-05:
      DOI: 10.1002/adfm.201600486
       
  • Delocalized Electron Accumulation at Nanorod Tips: Origin of Efficient H2
           Generation
    • Abstract: Photocatalytic hydrogen (H2) evolution requires efficient electron transfer to catalytically active sites in competition with charge recombination. Thus, controlling charge‐carrier dynamics in the photocatalytic H2 evolution process is essential for optimized photocatalyst nanostructures. Here, the efficient delocalization of electrons is demonstrated in a heterostructure consisting of optimized MoS2 tips and CdS nanorods (M‐t‐CdS Nrs) synthesized by amine‐assisted oriented attachment. The heterostructure achieves photocatalytic H2 activity of 8.44 mmol h−1 g−1 with excellent long‐term durability (>23 h) without additional passivation under simulated solar light (AM 1.5, 100 mW cm−2). This activity is nearly two orders of magnitude higher than that of pure CdS Nrs. The impressive photocatalytic H2 activity of M‐t‐CdS Nrs reflects favorable charge‐carrier dynamics, as determined by steady‐state PL and time‐correlated single photon counting correlation analysis at low temperature. The MoS2 cocatalysts precisely located at the end of the CdS Nrs exhibit ultrafast charge transfer and slow charge recombination via spatially localized deeper energy states, resulting in a highly efficient H2 evolution reaction in lactic acid containing an electrolyte. MoS2 tipped CdS nanorods synthesized by amine‐assisted oriented attachment exhibit ultrafast charge transfer and slow charge recombination via spatially localized deeper energy states, resulting in photocatalytic H2 activity of 8.44 mmol h−1 g−1 with excellent long‐term durability (>23 h) without additional passivation under simulated solar light.
      PubDate: 2016-04-25T15:03:10.561275-05:
      DOI: 10.1002/adfm.201600285
       
  • A Novel Photocathode Material for Sunlight‐Driven Overall Water
           Splitting: Solid Solution of ZnSe and Cu(In,Ga)Se2
    • Authors: Hiroyuki Kaneko; Tsutomu Minegishi, Mamiko Nakabayashi, Naoya Shibata, Yongbo Kuang, Taro Yamada, Kazunari Domen
      Abstract: Thin films of a solid solution of ZnSe and CuIn0.7Ga0.3Se2 ((ZnSe) x (CIGS) 1–x ) are prepared by co‐evaporation. Structural characterization reveals that the ZnSe and CIGS form a solid solution with no phase separation. (ZnSe)0.85(CIGS)0.15‐based photocathodes modified with Pt, Mo, Ti, and CdS exhibit a photocurrent of 7.1 mA cm−2 at 0 VRHE, and a relatively high onset potential of 0.89 VRHE under simulated sunlight. A two‐electrode cell containing a (ZnSe)0.85(CIGS)0.15 photocathode and a BiVO4‐based photoanode has an initial solar‐to‐hydrogen conversion efficiency of 0.91%, which is one of the highest values reported for a photoanode–photocathode combination. Thus, (ZnSe)0.85(CIGS)0.15 is a promising photocathode material for efficient photoelectrochemical water splitting. (ZnSe)0.85(CIGS)0.15‐based photocathodes for hydrogen evolution from water show a notably high onset potential of 0.89 VRHE under simulated sunlight. A photoelectrochemical cell composed of a (ZnSe)0.85(CIGS)0.15‐based photocathode and a BiVO4‐based photoanode drives overall water splitting utilizing simulated sunlight without an external bias voltage, exhibiting a solar‐to‐hydrogen conversion efficiency of 0.91%.
      PubDate: 2016-04-25T15:03:00.434836-05:
      DOI: 10.1002/adfm.201600615
       
  • Designing Multicolored Photonic Micropatterns through the Regioselective
           Thermal Compression of Inverse Opals
    • Abstract: Colloidal assemblies develop pronounced structural colors due to the selective diffraction of light. Micropatterns with multiple structural colors are appealing for the use in a variety of photonic applications. Here, a lithographic approach is reported, which provides a high level of control over the size, shape, and color of a micropattern using the anisotropic shrinkage of inverse opals made of a negative photoresist heated to high temperatures. Shrinkage occurs uniformly across the thickness of the film, leading to a blueshift in the structural color while maintaining a high reflectivity across the full visible spectrum. The rate of shrinkage is determined by the annealing temperature and the photoresist crosslinking density. The rate can, therefore, be spatially modulated by applying UV radiation through a photomask to create multicolor micropatterns from single‐colored inverse opals. The lateral dimensions of the micropattern features can be as small as the thickness of the inverse opal. Multicolored photonic micropatterns with high reflectivity and resolution are simply created by anisotropic shrinkage of inverse opals made of a negative photoresist. The rate of shrinkage is determined by annealing temperature and UV dose, which enables the spatial modulation of structural color through a photolithography. This spatially addressable and rate‐controllable anisotropic compression will benefit a wide range of photonic applications.
      PubDate: 2016-04-25T15:02:56.174378-05:
      DOI: 10.1002/adfm.201601095
       
  • Combinatorial Study of Temperature‐Dependent Nanostructure and
           Electrical Conduction of Polymer Semiconductors: Even Bimodal Orientation
           Can Enhance 3D Charge Transport
    • Authors: Sangsik Park; Moo Hyung Lee, Kwang Seok Ahn, Hyun Ho Choi, Jihye Shin, Jie Xu, Jianguo Mei, Kilwon Cho, Zhenan Bao, Dong Ryeol Lee, Moon Sung Kang, Do Hwan Kim
      Abstract: Temperature‐dependent (80–350 K) charge transport in polymer semiconductor thin films is studied in parallel with in situ X‐ray structural characterization at equivalent temperatures. The study is conducted on a pair of isoindigo‐based polymers containing the same π‐conjugated backbone with different side chains: one with siloxane‐terminated side chains (PII2T‐Si) and the other with branched alkyl‐terminated side chains (PII2T‐Ref). The different chemical moiety in the side chain results in a completely different film morphology. PII2T‐Si films show domains of both edge‐on and face‐on orientations (bimodal orientation) while PII2T‐Ref films show domains of edge‐on orientation (unimodal orientation). Electrical transport properties of this pair of polymers are also distinctive, especially at high temperatures (>230 K). Smaller activation energy (E A) and larger pre‐exponential factor (μ 0) in the mobility‐temperature Arrhenius relation are obtained for PII2T‐Si films when compared to those for PII2T‐Ref films. The results indicate that the more effective transport pathway is formed for PII2T‐Si films than for the other, despite the bimodally oriented film structure. The closer π–π packing distance, the longer coherence length of the molecular ordering, and the smaller disorder of the transport energy states for PII2T‐Si films altogether support the conduction to occur more effectively through a system with both edge‐on and face on orientations of the conjugated molecules. Reminding the 3D nature of conduction in polymer semiconductor, our results suggest that the engineering rules for advanced polymer semiconductors should not simply focus on obtaining films with conjugated backbone in edge‐on orientation only. Instead, the engineering should also encounter the contribution of the inevitable off‐directional transport process to attain effective transport from polymer thin films. 3D charge conduction behavior of sister isoindigo‐based polymer semiconductor thin films is described complementarily with X‐ray structural analyses at varying temperatures. Because the overall charge transport occurs three dimensionally, rather than through a simple 2D manner, films formed with mixtures of edge‐on and face‐on orientations can also be beneficial, as long as good π‐stacking is attained in molecular scale.
      PubDate: 2016-04-25T15:02:47.391527-05:
      DOI: 10.1002/adfm.201601164
       
  • Anion‐Selective Redox Electrodes: Electrochemically Mediated
           Separation with Heterogeneous Organometallic Interfaces
    • Authors: Xiao Su; Heather J. Kulik, Timothy F. Jamison, T. Alan Hatton
      Abstract: Redox species have been explored extensively for catalysis, energy storage, and molecular recognition. It is shown that nanostructured pseudocapacitive electrodes functionalized with ferrocene‐based redox polymers are an attractive platform for the selective sorptive separation of dilute organic anions from strong aqueous and organic electrolyte solutions, and subsequent release of the sorbed ions to a stripping phase through electrochemical control of the specific binding processes. A remarkable degree of selectivity is shown for carboxylates (–COO–), sulfonates (–SO3−), and phosphonates (–PO3−2) over inorganic anions such as PF6− and ClO4− (separation factor >140 in aqueous and >3000 in organic systems), and between carboxylates with various substituents, based on differences in electronic structure and density of the adsorbates, beyond size, and charge. Our organometallic redox electrodes are a promising platform for targeting aqueous and organic systems requiring high separation factors and fast throughput, such as in the recovery of value‐added products from organic synthesis and isolation of dilute yet highly toxic organic contaminants. The combination of spectroscopic experiments and quantum chemistry sheds light on a selective binding mechanism based on redox‐enhanced hydrogen bonding between the cyclopentadienyl ligand and the carboxylate functional group, with broader implications for molecular design, supramolecular recognition, and metallocene catalysis. Heterogeneous organometallic redox eletrodes show remarkable stoichiometric selectivity toward organic anions based on functional group affinity in the presence of competing ions. The ferrocene‐functionalized redox electrode is selective for carboxylates, sulfonates, and phosphonates over 33‐fold excess competing electrolyte based on a redox‐mediated H‐bonding interaction dependent on the electronic structure of the anion. This is one of the first anion‐selective redox electrodes based on electrochemically activated chemical interactions.
      PubDate: 2016-04-23T03:40:57.200855-05:
      DOI: 10.1002/adfm.201600079
       
  • Chitosan–Alginate Microcapsules Provide Gastric Protection and
           Intestinal Release of ICAM‐1‐Targeting Nanocarriers, Enabling
           GI Targeting In Vivo
    • Abstract: When administered intravenously, active targeting of drug nanocarriers (NCs) improves biodistribution and endocytosis. Targeting may also improve NC oral delivery to treat gastrointestinal (GI) pathologies or for systemic absorption. However, GI instability of targeting moieties compromises this strategy. This study explores whether encapsulation of antibody‐coated NCs in microcapsules would protect against gastric degradation, providing NC release and targeting in intestinal conditions. Nanoparticles coated with antibodies against intercellular adhesion molecule‐1 (anti‐ICAM) or nonspecific immunoglobulin G (IgG) are encapsulated in chitosan (shell) ‐ alginate (core) microcapsules. Encapsulation efficiency is >95% and NC relase from microcapsules in storage is
      PubDate: 2016-04-23T03:40:50.255524-05:
      DOI: 10.1002/adfm.201600084
       
  • Flexible Sodium‐Ion Pseudocapacitors Based on 3D Na2Ti3O7 Nanosheet
           Arrays/Carbon Textiles Anodes
    • Authors: Shengyang Dong; Laifa Shen, Hongsen Li, Gang Pang, Hui Dou, Xiaogang Zhang
      Abstract: Flexible energy storage devices are critical components for emerging flexible and wearable electronics. Improving the electrochemical performance of flexible energy storage devices depends largely on development of novel electrode architectures and new systems. Here, a new class of flexible energy storage device called flexible sodium‐ion pseudocapacitors is developed based on 3D‐flexible Na2Ti3O7 nanosheet arrays/carbon textiles (NTO/CT) as anode and flexible reduced graphene oxide film (GFs) as cathode without metal current collectors or conducting additives. The NTO/CT anode with advanced electrode architectures is fabricated by directly growing Na2Ti3O7 nanosheet arrays on carbon textiles with robust adhesion through a simple hydrothermal process. The flexible GF//NTO/CT configuration achieves a high energy density of 55 Wh kg−1 and high power density of 3000 W kg−1. Taking the fully packaged flexible sodium‐ion pseudocapacitors into consideration, the maximum practical volumetric energy density and power density reach up to 1.3 mWh cm−3 and 70 mW cm−3, respectively. In addition, the flexible GF//NTO/CT device demonstrates a stable electrochemical performances with almost 100% capacitance retention under harsh mechanical deformation. A new class of flexible energy storage device called flexible sodium‐ion pseudocapacitor is developed by using 3D flexible Na2Ti3O7 nanosheet arrays/carbon textile as anode and reduced graphene oxide films as cathode. Due to its structural features and hybrid energy storage mechanisms, the flexible sodium‐ion pseudocapacitor demonstrates high mechanical flexibility, high energy density, high power density, and long capacity retention.
      PubDate: 2016-04-23T03:40:45.633321-05:
      DOI: 10.1002/adfm.201600264
       
  • Preparation of MnCo2O4@Ni(OH)2 Core–Shell Flowers for Asymmetric
           Supercapacitor Materials with Ultrahigh Specific Capacitance
    • Authors: Yan Zhao; Linfeng Hu, Shuyan Zhao, Limin Wu
      Abstract: Supercapacitors have attracted much interest in the past decades owing to their important applications, but most of them are focused on solitary or simple metal oxides. Here, a novel supercapacitor electrode composed of multicomponent MnCo2O4@Ni(OH)2 belt‐based core–shell nanoflowers is reported by a facile and cost‐effective method. This hybrid electrode exhibits a significantly enhanced specific capacitance. An asymmetric supercapacitor based on this unique hybrid nanoflowers as anode and an activated carbon film as cathode demonstrates high energy density, high power density, and long cycling lifespan. Manganese cobalt spinel and nickel hydroxide hybrid belt‐based core–shell nanoflowers are successfully fabricated by a facile and cost‐effective strategy. The hybrid electrode exhibits an ultrahigh specific capacitance (2154 F g−1 at 5 A g−1). An asymmetric supercapacitor device based on this hybrid nanoflowers demonstrates high energy density, high power density, and long cycling lifespan.
      PubDate: 2016-04-23T03:40:39.795036-05:
      DOI: 10.1002/adfm.201600494
       
  • Bipolar Electrochemical Synthesis of WS2 Nanoparticles and Their
           Application in Magneto‐Immunosandwich Assay
    • Abstract: WS2 nanoparticles are prepared using bipolar electrochemistry. Obtained material exhibits high activity for hydrogen evolution reaction (HER) and it is used as a label in standard magneto‐immunosandwich assay for protein detection through HER. This new system shows high analytical performance in terms of a wide range, selectivity, sensitivity, and reproducibility. WS2 nanoparticles are prepared using bipolar electrochemistry. The potential applications of these materials as a label for protein detection are demonstrated utilizing hydrogen evolution reaction with electrochemical impedance spectroscopy as a transduction method. This new system shows high analytical performance in terms of a wide range, selectivity, sensitivity, and reproducibility.
      PubDate: 2016-04-23T03:40:30.279383-05:
      DOI: 10.1002/adfm.201600961
       
  • Mussel‐Inspired Approach to Constructing Robust Multilayered
           Alginate Films for Antibacterial Applications
    • Abstract: The exceptional mechanical properties of the byssus—the fibrous holdfast of mussels that provides underwater adhesion—have potential applications in medicine and technology. The catechol–Fe3+–catechol interaction underlies the unique properties of mussel byssus and has emerged as a tool for developing functional hybrid materials such as pH‐responsive, self‐healing gels. Herein, the construction of functional alginate (Alg) film on a solid substrate inspired by mussel byssus is reported. The approach consists of spin‐coating‐assisted deposition of Alg catechols onto a solid substrate and their subsequent crosslinking via catechol–Fe3+–catechol interactions. This yields robust and multilayered Alg films that are resistant to protein adsorption and suppress bacterial adhesion. This method can be used to create antibacterial films for coating implanted medical devices. A novel method for generating a multilayered alginate film is developed by mimicking the formation of cuticle layers around the byssus of mussels. The approach consists of spin‐coating‐assisted deposition of alginate catechols onto a solid substrate and their subsequent crosslinking via catechol–Fe3+–catechol interactions, which yields a robust alginate film that inhibits bacterial adhesion.
      PubDate: 2016-04-23T03:40:26.579876-05:
      DOI: 10.1002/adfm.201600613
       
  • Charge‐Carrier Density Independent Mobility in Amorphous
           Fluorene‐Triarylamine Copolymers
    • Authors: Alasdair J. Campbell; Ruth Rawcliffe, Alexander Guite, Jorge Costa Dantas Faria, Abhimanyu Mukherjee, Martyn A. McLachlan, Maxim Shkunov, Donal D. C. Bradley
      Abstract: A charge‐carrier density dependent mobility has been predicted for amorphous, glassy energetically disordered semiconducting polymers, which would have considerable impact on their performance in devices. However, previous observations of a density dependent mobility are complicated by the polycrystalline materials studied. Here charge transport in field‐effect transistors and diodes of two amorphous, glassy fluorene‐triarylamine copolymers is investigated, and the results explored in terms of a charge‐carrier density dependent mobility model. The nondispersive nature of the time‐of‐flight (TOF) transients and analysis of dark injection transient results and transistor transfer characteristics indicate a charge‐carrier density independent mobility in both the low‐density diode and the high‐density transistor regimes. The mobility values for optimized transistors are in good agreement with the TOF values at the same field, and both have the same temperature dependency. The measured transistor mobility falls two to three orders of magnitude below that predicted from the charge‐carrier density dependent model, and does not follow the expected power‐law relationship. The experimental results for these two amorphous polymers are therefore consistent with a charge‐carrier density independent mobility, and this is discussed in terms of polaron‐dominated hopping and interchain correlated disorder. Charge transport in diodes and transistors of two amorphous glassy fluorene‐triarylamine copolymers is found to be consistent with a charge‐carrier density independent mobility. This is in contradiction to many theoretical models, which predict a charge‐carrier density dependent mobility for such energetically disordered organic semiconductors. This could indicate that interchain correlations can smooth out the energy landscape in amorphous conjugated polymers.
      PubDate: 2016-04-21T03:50:29.901768-05:
      DOI: 10.1002/adfm.201504722
       
  • 2D Molecular Semiconductors: 2D Single‐Crystalline Molecular
           Semiconductors with Precise Layer Definition Achieved by
           Floating‐Coffee‐Ring‐Driven Assembly (Adv. Funct. Mater.
           19/2016)
    • Authors: Qijing Wang; Jun Qian, Yun Li, Yuhan Zhang, Daowei He, Sai Jiang, Yu Wang, Xinran Wang, Lijia Pan, Junzhuan Wang, Xizhang Wang, Zheng Hu, Haiyan Nan, Zhenhua Ni, Youdou Zheng, Yi Shi
      Pages: 3181 - 3181
      Abstract: On page 3139, Y. Li, X. Wang, Y. Shi, and co‐workers demonstrate a new strategy for the rapid growth of 2D single‐crystalline molecular semiconductors with precise layer definition by a floating‐coffee‐ring‐driven assembly. In particular, using bilayer molecular crystals, the field‐effect transistors yield a maximum carrier mobility of 13.0 cm2 V−1 s−1. This strategy helps improve this new class of 2D materials in low‐cost, large‐area, and high‐performance electronics.
      PubDate: 2016-05-18T02:26:26.801658-05:
      DOI: 10.1002/adfm.201670118
       
  • Stretchable Electronics: Stretchable and Transparent Biointerface Using
           Cell‐Sheet–Graphene Hybrid for Electrophysiology and Therapy
           of Skeletal Muscle (Adv. Funct. Mater. 19/2016)
    • Pages: 3182 - 3182
      Abstract: On page 3207, S. H. Choi, D.‐H. Kim, and co‐workers demonstrate a soft and transparent cell‐sheet–graphene hybrid comprising aligned, and differentiated C2C12 myoblasts on buckled, and mesh‐patterned graphene electrodes. The hybrid can monitor and/or actuate electrophysiological signals within muscle tissue without immune responses due to the high quality bio‐interface formed by the integrated cell sheet. Furthermore, transparency of the hybrid allows simultaneous optical stimulation and recording.
      PubDate: 2016-05-18T02:26:25.633115-05:
      DOI: 10.1002/adfm.201670119
       
  • Contents: (Adv. Funct. Mater. 19/2016)
    • Pages: 3183 - 3190
      PubDate: 2016-05-18T02:26:33.435083-05:
      DOI: 10.1002/adfm.201670120
       
  • 2D Single‐Crystalline Molecular Semiconductors with Precise Layer
           Definition Achieved by Floating‐Coffee‐Ring‐Driven
           Assembly
    • Authors: Qijing Wang; Jun Qian, Yun Li, Yuhan Zhang, Daowei He, Sai Jiang, Yu Wang, Xinran Wang, Lijia Pan, Junzhuan Wang, Xizhang Wang, Zheng Hu, Haiyan Nan, Zhenhua Ni, Youdou Zheng, Yi Shi
      Pages: 3191 - 3198
      Abstract: 2D organic materials with in‐plane van der Waals forces among molecules have unique characteristics that ensure a brilliant future for multifunctional applications. Soluble organic semiconductors can be used to achieve low‐cost and high‐throughput manufacturing of electronic devices. However, achieving solution‐processed 2D single‐crystalline semiconductors with uniform morphology remains a substantial challenge. Here, the fabrication of 2D molecular single‐crystal semiconductors with precise layer definition by using a floating‐coffee‐ring‐driven assembly is presented. In particular, bilayer molecular films exhibit single‐crystalline features with atomic smoothness and high film uniformity over a large area; field‐effect transistors yield average and maximum carrier mobilities of 4.8 and 13.0 cm2 V−1 s−1, respectively. This work demonstrates the strong potential of 2D molecular crystals for low‐cost, large‐area, and high‐performance electronics. The floating‐coffee‐ring‐driven assembly of 2D single‐crystalline molecular semiconductors with precise layer definition is presented. Typical single‐crystalline features, atomic smoothness, and high morphologic uniformity over a large area are achieved. Field‐effect transistors devices yield a maximum carrier mobility of 13.0 cm2 V−1 s−1 and thus show promise for low‐cost, large‐area, and high‐performance electronics.
      PubDate: 2016-03-23T06:10:34.067434-05:
      DOI: 10.1002/adfm.201600304
       
  • Light‐Driven Delivery and Release of Materials Using Liquid Marbles
    • Pages: 3199 - 3206
      Abstract: Remote control of the locomotion of small objects is a challenge in itself and may also allow for the stimuli control of entire systems. Here, it is described how encapsulated liquids, referred to as liquid marbles, can be moved on a water surface with a simple near‐infrared laser or sunlight. Using light rather than pH or temperature as an external stimulus allows for the control of the position, area, timing, direction, and velocity of delivery. This approach makes it possible to not only transport the materials encapsulated within the liquid marble but also to release them at a specific place and time, as controlled by external stimuli. Furthermore, it is shown that liquid marbles can work as light‐driven towing engines to push or pull objects. Being able to remotely transport and push/pull the small objects by light and control the release of active substances on demand should open up a wide field of conceivable applications. Remotely controlling the locomotion of small objects is fascinating, especially for transportation of material. Here, the remote and light‐driven actuation of liquid marbles on a water surface and the subsequent on‐demand release of their encapsulated content are described. Furthermore, it is shown that liquid marbles can be exploited as light‐driven towing engines to push or pull objects.
      PubDate: 2016-03-15T02:40:52.36688-05:0
      DOI: 10.1002/adfm.201600034
       
  • Stretchable and Transparent Biointerface Using
           Cell‐Sheet–Graphene Hybrid for Electrophysiology and Therapy
           of Skeletal Muscle
    • Pages: 3207 - 3217
      Abstract: Implantable electronic devices for recording electrophysiological signals and for stimulating muscles and nerves have been widely used throughout clinical medicine. Mechanical mismatch between conventional rigid biomedical devices and soft curvilinear tissues, however, has frequently resulted in a low signal to noise ratio and/or mechanical fatigue and scarring. Multifunctionality ranging from various sensing modalities to therapeutic functions is another important goal for implantable biomedical devices. Here, a stretchable and transparent medical device using a cell‐sheet–graphene hybrid is reported, which can be implanted to form a high quality biotic/abiotic interface. The hybrid is composed of a sheet of C2C12 myoblasts on buckled, mesh‐patterned graphene electrodes. The graphene electrodes monitor and actuate the C2C12 myoblasts in vitro, serving as a smart cell culture substrate that controls their aligned proliferation and differentiation. This stretchable and transparent cell‐sheet–graphene hybrid can be transplanted onto the target muscle tissue, to record electromyographical signals, and stimulate implanted sites electrically and/or optically in vivo. Additional cellular therapeutic effect of the cell‐sheet–graphene hybrid is obtained by integrated myobalst cell sheets. Any immune responses within implanted muscle tissues are not observed. This multifunctional device provides many new opportunities in the emerging field of soft bioelectronics. Stretchable and transparent cell‐sheet–graphene hybrid composed of cultured C2C12 myoblast sheets on mesh‐patterned, and buckled graphene electrodes brings high quality biotic/abiotic interface with multifunctional properties ranging from various sensing and actuating modalities to therapeutic functions in vitro and in vivo. Reduced acute immune responses due to the cell sheet support the advantage of the cell‐sheet–graphene hybrid.
      PubDate: 2016-03-15T02:42:01.734759-05:
      DOI: 10.1002/adfm.201504578
       
  • Reversible Electrochemically Triggered Delamination Blistering of Hydrogel
           Films on Micropatterned Electrodes
    • Authors: Ben B. Xu; Qihan Liu, Zhigang Suo, Ryan C. Hayward
      Pages: 3218 - 3225
      Abstract: Stimuli responsive elastic instabilities provide opportunities for controlling the structures and properties of polymer surfaces, offering a range of potential applications. Here, a surface actuator based on a temperature and electrically responsive poly(N‐isopropyl acrylamide‐co‐sodium acrylate) hydrogel that undergoes a two‐step delamination and buckling instability triggered using micropatterned electrodes is described. The electrically actuated structures entail large out‐of‐plane displacements that take place on time‐scales of less than 1 s, in response to modest triggering voltages (−3–6 V). Alongside these experimental observations, finite element simulations are conducted to better understand the two‐step nature of the instability. In the first step, hydrogel films undergo delamination and formation of blisters, facilitated by electrochemical reduction of the thiol groups anchoring the film to the electrodes. Subsequently, at larger reducing potentials, the electrolytic current is sufficient to nucleate a gas bubble between the electrode and the gel, causing the delaminated region to adopt a straight‐sided blister shape. Finally, thermally induced deswelling of the gel allows the film to be returned to its flat state and readhered to the electrode, thereby allowing for repeated actuation. Delamination and buckling of hydrogels in a controlled, localized, and reversible manner are demonstrated using electrochemical‐triggered debonding and inflation of a gas bubble. The process provides rapid and large amplitude out‐of‐plane displacements, while thermally induced deswelling of the gel allows devices to be reset and actuated over multiple cycles.
      PubDate: 2016-03-30T06:11:43.723436-05:
      DOI: 10.1002/adfm.201504769
       
  • Interfacial Crystallization‐Driven Assembly of Conjugated
           Polymers/Quantum Dots into Coaxial Hybrid Nanowires: Elucidation of
           Conjugated Polymer Arrangements by Electron Tomography
    • Pages: 3226 - 3235
      Abstract: A simple and practical “solution‐biphase method” allows the preparation of efficient charge‐transporting 1D nanocrystals with coaxial p–n junctions. It involves gradual diffusion of a top layer of poor solvent (acetonitrile) into a bottom layer of poly(3‐hexyl thiophene)‐b‐poly(2‐vinyl pyridine) (P3HT‐b‐P2VP) conjugated polymers (CPs) and CdSe quantum dots (QDs) dissolved in chloroform. Initial interfacial crystallization‐driven assembly of CPs results in the formation of seeds consisting of dimeric QDs transversely bridged by CPs. Coaxial CPs/QDs hybrid NWs are generated by 1D growth of QDs‐dimeric seeds, enabling tracing of the CPs‐crystallization process via the QDs. Thus, well‐arranged QDs along the longitudinal axis of the NWs infer highly crystalline CPs with edge‐on orientation, as confirmed by electron tomography, UV–vis spectroscopy, and grazing‐incidence wide‐angle X‐ray scattering. This high cristallinity as well as the increased length of the resulting hybrid NWs in solution and the corresponding crystallite size in as‐cast film represent a significant improvement compared to the conventional “one‐pot addition method”. Moreover, although randomly QDs‐attached hybrids of P3HT homopolymer are produced by the solution‐biphase method, branched aggregates with micrometer‐long NW arms are generated from the crystal seeds containing multiple growth facets without precipitate, despite acetonitrile being a nonsolvent. Solution‐biphase interfacial crystallization‐driven assembly of conjugated polymers (CPs) with quantum dots (QDs) facilitates the fabrication of efficient charge‐transporting nanowires (NWs) with coaxial p–n junctions. 1D growth of dimeric QDs transversely bridged by CPs forms these NWs, enabling elucidation of the crystalline packing arrangements of CP within the hybrid nanowires via transmission electron tomography of QDs tracers.
      PubDate: 2016-03-02T08:03:33.903848-05:
      DOI: 10.1002/adfm.201504964
       
  • Spontaneous and Directional Transportation of Gas Bubbles on
           Superhydrophobic Cones
    • Authors: Cunming Yu; Moyuan Cao, Zhichao Dong, Jingming Wang, Kan Li, Lei Jiang
      Pages: 3236 - 3243
      Abstract: Understanding the behavior of gas bubbles in aqueous media and realizing their spontaneous and directional manipulation are of vital importance in both scientific research and industrial applications, owing to their significant influences on many processes, such as waste water treatment, gas evolution reactions, and the recovery of valuable minerals. However, the behaviors of gas bubbles in aqueous media are mainly dominated by the buoyant force, which greatly impedes gas bubble transportation to any other direction except upward. Consequently, the spontaneous and directional transportation of gas bubbles in aqueous media is still identified as a big issue. Here, superhydrophobic copper cones have been successfully fabricated by integrating low‐surface‐tension chemical coatings with conical morphology. The generated superhydrophobic copper cones are capable of transporting gas bubbles from their tip to the base spontaneously and directionally underwater, even when they are vertically fixed with tips pointing up. The present study will inspire people to develop novel strategies to achieve efficient manipulation of gas bubbles in practical applications. Superhydrophobic cones are fabricated by applying superhydrophobic coating to copper cones. Arising from its superhydrophobic wettability and conical morphology, the superhydrophobic cone carries a stable air film and possesses a Laplace pressure gradient. Assisted by these properties, the superhydrophobic cone can facilitate spontaneous sand directional transport of gas bubbles, especially microscopic bubbles.
      PubDate: 2016-03-30T06:11:36.60774-05:0
      DOI: 10.1002/adfm.201505234
       
  • Metal‐Organic‐Framework‐Coated Optical Fibers as
           Light‐Triggered Drug Delivery Vehicles
    • Pages: 3244 - 3249
      Abstract: Physical delivery of anticancer drugs in controlled anatomic locations can complement the advances being made in chemo‐selective therapies. To this end, an optical fiber catheter is coated in a thin layer of metal organic framework UiO‐66 and the anticancer drug 5‐Fluorouracil (5‐FU) is deposited within the pores. Delivery of light of appropriate wavelength through the fiber catheter is found to trigger the release of 5‐FU on demand, offering a new route to localized drug administration. The system exhibits great potential with as much as 110 × 10−6 m of 5‐FU delivered within 1 min from one fiber. Encapsulation and controlled release of 5‐Fluorouracil from the UiO‐66 thin film optical fiber is reported. The active drug is released upon switching on the light at the other end of the optical fiber, making it a convenient method to deliver toxic drugs into remote areas of human body.
      PubDate: 2016-03-08T13:18:12.932876-05:
      DOI: 10.1002/adfm.201505260
       
  • Achieving Above 60% External Quantum Efficiency in Organic
           Light‐Emitting Devices Using ITO‐Free Low‐Index
           Transparent Electrode and Emitters with Preferential Horizontal Emitting
           Dipoles
    • Pages: 3250 - 3258
      Abstract: Comprehensive theoretical and experimental studies are reported on organic light‐emitting devices (OLEDs) adopting either the conventional high‐index indium tin oxide (ITO) electrode or the low‐index conducting polymer electrode, either isotropic emitters or emitters having preferentially horizontal emitting dipoles, and different layer structures. Intriguingly, with the use of low‐index electrode in the device, in addition to the known suppression of waveguided modes, the surface plasmon modes can also be effectively suppressed with larger emitter‐to‐metal distances yet with better immunity to accompanied increase of the competing waveguided modes (induced by thicker organic layers) as in the ITO device. As a result, overall coupling efficiencies of OLED internal radiation into substrates can be significantly enhanced over those with ITO electrodes. Through effective extraction of radiation within substrates, green phosphorescent OLEDs adopting both the low‐index ITO‐free electrode and the preferentially horizontal dipole emitter (with a horizontal dipole ratio of 76%) achieve a high external quantum efficiency (EQE) of up to ≈64%. The simulation also predicts that very high EQEs of ≥80% are possible with highly horizontal dipole emitters for all red/green/blue/white OLEDs, clearly revealing the potential of combining low‐index transparent electrodes and horizontal dipole emitters for high‐efficiency OLEDs. A combination of low‐index transparent electrodes and preferentially horizontal dipole emitters realizes organic light‐emitting devices with ≈64% external quantum efficiency (EQE). In addition to suppressing waveguided modes, low‐index electrodes also effectively suppress surface plasmon modes with larger emitter‐to‐metal distances yet with better immunity to accompanied increase of competing waveguided modes, resulting in enhanced coupling efficiencies into substrates and EQEs.
      PubDate: 2016-02-08T02:59:28.155905-05:
      DOI: 10.1002/adfm.201505312
       
  • Transforming Common III–V and II–VI Semiconductor Compounds
           into Topological Heterostructures: The Case of CdTe/InSb Superlattices
    • Authors: Qihang Liu; Xiuwen Zhang, L. B. Abdalla, Alex Zunger
      Pages: 3259 - 3267
      Abstract: Currently, known topological insulators (TIs) are limited to narrow gap compounds incorporating heavy elements, thus severely limiting the material pool available for such applications. It is shown via first‐principle calculations that a heterovalent superlattice made of common semiconductor building blocks can transform its non‐TI components into a topological nanostructure, illustrated by III–V/II–VI superlattice InSb/CdTe. The heterovalent nature of such interfaces sets up, in the absence of interfacial atomic exchange, a natural internal electric field that along with the quantum confinement leads to band inversion, transforming these semiconductors into a topological phase while also forming a giant Rashba spin splitting. The relationship between the interfacial stability and the topological transition is revealed, finding a “window of opportunity” where both conditions can be optimized. Once a critical InSb layer thickness above ≈1.5 nm is reached, both [111] and [100] superlattices have a relative energy of 1.7–9.5 meV Å–2, higher than that of the atomically exchanged interface and an excitation gap up to ≈150 meV, affording room‐temperature quantum spin Hall effect in semiconductor superlattices. The understanding gained from this study could broaden the current, rather restricted repertoire of functionalities available from individual compounds by creating next‐generation superstructured functional materials. First‐principle calculations reveal how a heterovalent superlattice can transform its topological‐trivial components into a topological nanostructure, illustrated by InSb/CdTe superlattices. The heterovalent nature of such interfaces sets up an internal electric field that leads to topological transition. This work also illustrates how to make realistic predictions on topological insulators by coevaluating the competition between thermodynamic stability and band inversion.
      PubDate: 2016-03-30T08:10:28.840129-05:
      DOI: 10.1002/adfm.201505357
       
  • Synthesis and Functionalization of Oriented
           Metal–Organic‐Framework Nanosheets: Toward a Series of 2D
           Catalysts
    • Authors: Guowu Zhan; Hua Chun Zeng
      Pages: 3268 - 3281
      Abstract: Synthesis of metal–organic frameworks (MOFs) is based on coordination‐driven self‐assembly of metal ions and organic ligands. However, to date, it remains difficult to adjust the coordination behaviors of MOFs and then control geometric shapes of nanostructures; especially their morphologies in 1D nanofibers or 2D nanosheets have seldom been explored. Here, a facile route at room temperature and ambient pressure is reported for the preparation of copper‐based MOFs with low‐dimensional shapes (i.e., nanofibers, nanorods, nanosheets, and nanocuboids), via thermodynamic and kinetic controls over the anisotropic growth. Importantly, the as‐prepared 2D MOF nanosheets with monocrystalline nature (100% exposed {010} facets) provide a material platform to the fabrication of 2D supported metal nanocatalysts. First, the MOF nanosheets can serve as a self‐templating solid precursor to prepare different CuO and CuO‐Cu2O nanocomposites, or even Cu metals via thermolysis or reduction under controlled atmospheres. Upon their formation, second, ultrafine noble metal nanoparticles (e.g., Au, Ag, Pt, Pd, Au0.4Pt0.6, Au0.4Pd0.6, and Au0.3Pt0.3Pd0.4) can be exclusively anchored on the external surfaces of the MOF nanosheets. To show their open accessibility, catalytic activities of the derived catalysts have been evaluated using CO2 hydrogenation and 4‐nitrophenol reduction in gas phase and liquid phase, respectively. A shape‐controlled method is devised for fabrication of a series of low‐dimensional copper‐containing metal–organic‐framework (MOF) crystals by using Cu2O nanoparticles as a copper source. The oriented MOF nanosheets can serve as a single‐source solid precursor or an ideal support for 2D‐nanocatalyst fabrication. Here, heterogeneous catalysis reactions have also been used to demonstrate the advantage of these MOF‐derived catalysts.
      PubDate: 2016-03-31T11:42:56.372177-05:
      DOI: 10.1002/adfm.201505380
       
  • Understanding the Shape Memory Behavior of Self‐Bending Materials
           and Their Use as Sensors
    • Authors: Xue Li; Michael J. Serpe
      Pages: 3282 - 3290
      Abstract: By depositing layers composed of poly (N‐isopropylacrylamide)‐based microgels and the polyelectrolyte polydiallyldimethylammonium chloride on a flexible substrate, responsive materials that bend upon drying can be fabricated; the extent of the bending depends on atmospheric humidity. This study shows that the bending conformation/direction can be templated, and exhibits shape memory. Detailed examination of the bilayer system leads to an understanding of the phenomena leading to this behavior. By close examination of microscopy images and diffraction patterns, this study is able to determine that the dried polymer‐based layer is composed of both amorphous and crystalline phases; the amorphous phase can readily absorb water, which results in actuation, while the crystalline phases template the bending characteristics of the device. With an understanding of the bending behavior of the devices, this study is able to generate humidity sensors by interfacing them with stretchable strain sensors, which are also developed specifically for the bendable materials. Initial bending direction/orientation of a bilayer‐like structure “templates” its future bending direction/orientation. This is demonstrated by cutting out specific regions of a pre‐bent material, and observing that they bend as if they are still a part of the “parent” structure. Interestingly, they bend differently than structures of the same size that were never pre‐bent. The templated bending is then exploited to generate humidity sensors.
      PubDate: 2016-02-16T11:23:40.150636-05:
      DOI: 10.1002/adfm.201505391
       
  • A Synergistic System for Lithium–Oxygen Batteries in Humid
           Atmosphere Integrating a Composite Cathode and a Hydrophobic Ionic
           Liquid‐Based Electrolyte
    • Authors: Shichao Wu; Jing Tang, Fujun Li, Xizheng Liu, Yusuke Yamauchi, Masayoshi Ishida, Haoshen Zhou
      Pages: 3291 - 3298
      Abstract: Moisture in air is a major obstacle for realizing practical lithium‐air batteries. Here, we integrate a hydrophobic ionic liquid (IL)‐based electrolyte and a cathode composed of electrolytic manganese dioxide and ruthenium oxide supported on Super P (carbon black) to construct a promising system for Li‐O2 battery that can be sustained in humid atmosphere (RH: 51%). A high discharge potential of 2.94 V and low charge potential of 3.34 V for 218 cycles are achieved. The outstanding performance is attributed to the synergistic effect of the unique hydrophobic IL‐based electrolyte and the composite cathode. This is the first time that such excellent performance is achieved in humid O2 atmosphere and these results are believed to facilitate the realization of practical lithium‐air batteries. An excellent, stable Li–O2 battery in humid atmosphere is designed for the first time. At a relative humidity of 51%, a small discharge–charge potential gap of 0.40 V and long cycle life of 218 cycles are achieved. These outstanding performance can be attributed to the synergistic effect of using a composite cathode, a hydrophobic ionic liquid‐based electrolyte, and the moisture in the atmosphere.
      PubDate: 2016-02-29T03:52:57.03335-05:0
      DOI: 10.1002/adfm.201505420
       
  • Monolayer MoS2 Dendrites on a Symmetry‐Disparate SrTiO3 (001)
           Substrate: Formation Mechanism and Interface Interaction
    • Authors: Yu Zhang; Qingqing Ji, Jinxiu Wen, Jiu Li, Cong Li, Jianping Shi, Xiebo Zhou, Kebin Shi, Huanjun Chen, Yuanchang Li, Shaozhi Deng, Ningsheng Xu, Zhongfan Liu, Yanfeng Zhang
      Pages: 3299 - 3305
      Abstract: Dendritic patterns generated in non‐equilibrium growth processes are prevalent in nature while their formation mechanisms are far from fully understood. Here, we report a coverage‐dependent fractal degree evolution of monolayer 2H‐MoS2 dendrites synthesized on a symmetry‐disparate substrate of SrTiO3 (001). Surprisingly, various characterizations have revealed that the monolayer dendrites featured with orthogonal backbones are single crystalline, possessing both peculiar adlayer‐substrate interaction and abnormal indirect bandgap on SrTiO3 (001). Further theoretical calculations indicate that a prominent diffusion anisotropy of monomer precursors, combined with the disparate adlayer‐substrate symmetry, determine the diffusion‐limited aggregation of MoS2 towards dendritic shapes. This work provides brand‐new insights in the morphological engineering of two‐dimensional atomic crystals, and contributes greatly to an in‐depth understanding of the detailed dynamics in non‐equilibrium crystal growth. A morphologically engineered growth of monolayer MoS2 dendrites is reported. Such diffusion‐limited aggregation behavior is proposed to be mediated by a prominent diffusion anisotropy of monomer MoS x precursors on SrTiO3 (001), in combination with the symmetry disparity of MoS2 adlayer and SrTiO3 substrates.
      PubDate: 2016-03-15T02:41:05.188865-05:
      DOI: 10.1002/adfm.201505571
       
  • High‐Performance Hybrid White Organic Light‐Emitting Diodes
           with Superior Efficiency/Color Rendering Index/Color Stability and Low
           Efficiency Roll‐Off Based on a Blue Thermally Activated Delayed
           Fluorescent Emitter
    • Authors: Zhongbin Wu; Jiajia Luo, Ning Sun, Liping Zhu, Hengda Sun, Ling Yu, Dezhi Yang, Xianfeng Qiao, Jiangshan Chen, Chuluo Yang, Dongge Ma
      Pages: 3306 - 3313
      Abstract: Thermally activated delayed fluorescence (TADF)‐based white organic light‐emitting diodes (WOLEDs) are highly attractive because the TADF emitters provide a promising alternative route to harvest triplet excitons. One of the major challenges is to achieve superior efficiency/color rendering index/color stability and low efficiency roll‐off simultaneously. In this paper, high‐performance hybrid WOLEDs are demonstrated by employing an efficient blue TADF emitter combined with red and green phosphorescent emitters. The resulting WOLED shows the maximum external quantum efficiency, current efficiency, and power efficiency of 23.0%, 51.0 cd A−1, and 51.7 lm W−1, respectively. Moreover, the device exhibits extremely stable electroluminescence spectra with a high color rendering index of 89 and Commission Internationale de L'Eclairage coordinates of (0.438, 0.438) at the practical brightness of 1000 cd m−2. The achievement of these excellent performances is systematically investigated by versatile experimental and theoretical evidences, from which it is concluded that the utilization of a blue‐green‐red cascade energy transfer structure and the precise manipulation of charges and excitons are the key points. It can be anticipated that this work might be a starting point for further research towards high‐performance hybrid WOLEDs. High‐performance hybrid white organic emitting‐light diodes (WOLEDs) are demonstrated by using an efficient blue thermally activated delayed fluorescent emitter combined with red and green phosphorescent emitters. The resulting WOLEDs show the maximum external quantum efficiency, current efficiency, and power efficiency of 23.0%, 51.0 cd A−1, and 51.7 lm W−1, respectively, with a high color rendering index of 89.
      PubDate: 2016-02-24T13:21:09.789696-05:
      DOI: 10.1002/adfm.201505602
       
  • Efficient and Stable Bifunctional Electrocatalysts Ni/NixMy (M = P, S) for
           Overall Water Splitting
    • Pages: 3314 - 3323
      Abstract: Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni8P3 and Ni/Ni9S8 electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni8P3 as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm−2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO2 and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels. Three‐dimension nickel‐based electrocatalytic electrodes (Ni/Ni8P3 and Ni/Ni9S8) are developed for application in water splitting. The as‐obtained Ni/Ni8P3 catalytic electrode, particularly exhibiting excellent electrocatalytic activity and stability due to its advanced structure effects, can serve as a highly efficient and stable bifunctional catalyst for overall water splitting.
      PubDate: 2016-03-10T23:40:51.532652-05:
      DOI: 10.1002/adfm.201505626
       
  • Photocurrent Extraction Efficiency near Unity in a Thick Polymer Bulk
           Heterojunction
    • Pages: 3324 - 3330
      Abstract: The detailed characterization of a dialkoxyphenylene‐difluorobenzothiadiazole based conjugated polymer poly[(2,5‐bis(2‐hexyldecyloxy)phenylene)‐alt‐(5,6‐difluoro‐4,7‐di(thiophen‐2‐yl)benzo[c][1,2,5]thiadiazole)] (PPDT2FBT) is reported. PPDT2FBT closely tracks theoretical photocurrent production while maintaining a high fill factor in remarkably thick films. In order to understand the properties that enable PPDT2FBT to function with thick active layers, the effect of film thickness on the material properties and device parameters was carefully studied and compared to three benchmark polymers. Optical modeling, grazing incidence wide angle X‐ray scattering, cross‐sectional transmission electron microscopy, transient photoconductivity, and extensive device work were carried out and have clarified the key structural features and properties that allow such thick active layers to function efficiently. The unique behavior of thick PPDT2FBT films arises from high vertical carrier mobility, an isotropic morphology with strong, vertical π–π stacking, and a suitable energy band structure. These physical characteristics allow efficient photocurrent extraction, internal quantum efficiencies near 100% and power conversion efficiencies over 9% from exceptionally thick active layers in both conventional and inverted architectures. The ability of PPDT2FBT to function efficiently in thick cells allows devices to fully attenuate incident sunlight while providing a pathway to defect‐free film processing over large areas, constituting a major advancement toward commercially viable organic solar cells. A unique conjugated polymer (PPDT2FBT) is found to closely track theoretical photocurrent production and maintain a high fill factor in remarkably thick films. The unique behavior of thick PPDT2FBT films arises from high vertical carrier mobility and a morphology with strong, vertical π–π stacking, allowing efficient photocurrent extraction and internal quantum efficiencies near 100% from exceptionally thick active layers.
      PubDate: 2016-02-22T07:24:37.033757-05:
      DOI: 10.1002/adfm.201505556
       
  • Novel Composites of α‐Fe2O3 Tetrakaidecahedron and Graphene
           Oxide as an Effective Photoelectrode with Enhanced Photocurrent
           Performances
    • Authors: Shaoxiong Liu; Lingxia Zheng, Pingping Yu, Sancan Han, Xiaosheng Fang
      Pages: 3331 - 3339
      Abstract: Novel composites composed of α‐Fe2O3 tetrakaidecahedrons and graphene oxide have been easily fabricated and demonstrated to be efficient photoelectrodes for photoelectrochemical water splitting reaction with superior photocurrent response. α‐Fe2O3 tetrakaidecahedrons are facilely synthesized in a green manner without any organic additives and then modified with graphene oxide. The morphological and structural properties of α‐Fe2O3/graphene composite are intensively investigated by several means, such as X‐ray diffraction, field‐emission scanning electron microscope, transmission electron microscope, X‐ray photoelectron spectroscopy, Fourier Transform infrared spectroscopy, and Raman spectroscopy. The tetrakaidecahedronal hematite particles have been indicated to be successfully coupled with graphene oxide. Systematical photoelectrochemical and impedance spectroscopy measurements have been carried out to investigate the favorable performance of α‐Fe2O3/graphene composites, which are found to be effective photoanodes with rapid, steady, and reproducible feature. The coupling of graphene with α‐Fe2O3 particles has greatly enhanced the photoelectrochemical performance, resulting in higher photocurrent and lower onset potential than that of pure α‐Fe2O3. This investigation has provided a feasible method to synthesize α‐Fe2O3 tetrakaidecahedron and fabricate an efficient α‐Fe2O3/graphene photoelectrode for photoelectrochemical water oxidation, suggesting a promising route to design noble metal free semiconductor/graphene photocatalysts. Fine α‐Fe2O3 tetrakaidecahedrons have been successfully synthesized by a facile hydrothermal process, which is then coupled with graphene oxide. The composite of α‐Fe2O3 tetrakaidecahedron/graphene oxide acts as an efficient photoelectrode with a rapid, stable, and reproducible photocurrent response. The photoelectrochemical performance of pure α‐Fe2O3 is obviously enhanced by the coupling of graphene oxide in the composite.
      PubDate: 2016-03-15T02:41:12.432094-05:
      DOI: 10.1002/adfm.201505554
       
  • Unconventional Carbon: Alkaline Dehalogenation of Polymers Yields
           N‐Doped Carbon Electrode for High‐Performance Capacitive
           Energy Storage
    • Authors: Guoxin Zhang; Lin Wang, Yongchao Hao, Xiuyan Jin, Yuqi Xu, Yun Kuang, Liming Dai, Xiaoming Sun
      Pages: 3340 - 3348
      Abstract: Polymers are important precursors for the fabrication of carbon materials. Herein, halogenated polymers are explored as precursors for the synthesis of high‐quality carbon materials via alkaline dehalogenation. It is found that the halogen elements (F, Cl) connecting to vinylidene units are highly reactive so that dehalogenation can take place a few seconds at room temperature by simple hand grinding in the presence of strong inorganic alkaline. Furthermore, the halogen element‐leaving sites are shown to be susceptible to heteroatom doping (e.g., N doping) to become stable capacitive sites for charge storage (e.g., ions). By using a mixture of NaOEt and KOH as dehalogenation reagents, abundant hierarchical pores (macro/meso/micropores) in the resultant doped carbon matrix for fast mass transportation can be created. Very high capacitance (328 F g−1 at 0.5 A g−1) and rate capability (75.3% retention at 50 A g−1 and 62.5% retention at 100 A g−1) are observed for the newly developed halogenated polymer‐derived doped carbon materials. Halogenated polymers are explored as a new type of precursors to synthesize high‐quality carbons. Dehalogenation occurs within several seconds at room temperature in the presence of strong alkaline in dimethylformamide. Subsequent annealing leads to N‐doped carbon of superior capacitive behavior with a high energy/power density, high rate capability, and good long‐term stability.
      PubDate: 2016-03-29T07:37:54.761482-05:
      DOI: 10.1002/adfm.201505533
       
  • MoS2‐Quantum‐Dot‐Interspersed Li4Ti5O12 Nanosheets with
           Enhanced Performance for Li‐ and Na‐Ion Batteries
    • Authors: Guobao Xu; Liwen Yang, Xiaolin Wei, Jianwen Ding, Jianxin Zhong, Paul K. Chu
      Pages: 3349 - 3358
      Abstract: Rational nanoscale surface engineering of electroactive nanoarchitecture is highly desirable, since it can both secure high surface‐controlled energy storage and sustain the structural integrity for long‐time and high‐rate cycling. Herein, ultrasmall MoS2 quantum dots (QDs) are exploited as surface sensitizers to boost the electrochemical properties of Li4Ti5O12 (LTO). The LTO/MoS2 composite is prepared by anchoring 2D LTO nanosheets with ultrasmall MoS2 QDs using a simple and effective assembly technique. Impressively, such 0D/2D heterostructure composites possess enhanced surface‐controlled Li/Na storage behavior. This unprecedented Li/Na storage process provides a LTO/MoS2 composite with outstanding Li/Na storage properties, such as high capacity and high‐rate capability as well as long‐term cycling stability. As anodes in Li‐ion batteries, the materials have a stable specific capacity of 170 mAhg−1 after 20 cycles and are able to retain 94.1% of this capacity after 1000 cycles, i.e., 160 mAhg−1, at a high rate of 10 C. Due to these impressice performance, the presented 0D/2D heterostructure has great potential in high‐performance LIBs and sodium‐ion batteries. A smart hybrid of ultrasmall MoS2‐quantum‐dot‐interspersed LTO nanosheets is prepared. The 0D/2D heterostructure of the LTO/MoS2 composite conduces to enhanced surface‐controlled Li/Na storage behavior, resulting in high capacity, extraordinary rate capability, and remarkable cycling stability.
      PubDate: 2016-03-02T07:56:07.03932-05:0
      DOI: 10.1002/adfm.201505435
       
  • Biologically Inspired and Magnetically Recoverable Copper Porphyrinic
           Catalysts: A Greener Approach for Oxidation of Hydrocarbons with Molecular
           Oxygen
    • Pages: 3359 - 3368
      Abstract: An efficient synthetic method for magnetically recoverable hybrid copper porphyrinic nanomaterials is reported. These functionalized magnetic materials prove to be efficient bioinspired oxidation catalysts of olefins and thiols, using molecular oxygen as oxidant, in total absence of reductants and solvents, with the highest TON (turnover number) yet achieved for this reaction (≈200 000). A comparative study between homogeneous and heterogeneous oxidation of cyclohexene is discussed, revealing the heterogeneous system to be the most promising concerning stability and reusability of the catalysts. The full characterization of the magnetic hybrid porphyrinic nanomaterials, by transmission electron microscopy, flame atomic absorption spectrometry, thermogravimetry, N2 sorption, and infrared spectroscopy, is also described. An efficient synthetic method for magnetically recoverable hybrid copper porphyrin based nanomaterials is reported. These prove to be stable and reusable efficient bioinspired oxidation catalysts of olefins and thiols, using molecular oxygen as oxidant, in total absence of reductants and solvents, with the highest turnover number yet achieved for this reaction (≈200 000).
      PubDate: 2016-02-12T07:03:54.471107-05:
      DOI: 10.1002/adfm.201505405
       
  • Liquid Marbles: Light‐Driven Delivery and Release of Materials Using
           Liquid Marbles (Adv. Funct. Mater. 19/2016)
    • Pages: 3372 - 3372
      Abstract: Light‐driven delivery of materials using liquid marbles is described by H. Mayama, S. Fujii, and co‐workers on page 3199, with the liquid marbles shown to work as light‐driven towing engines. This approach allows for not only the transport of the materials encapsulated within the liquid marble but also their release at a specific place and at a time determined by external stimuli.
      PubDate: 2016-05-18T02:26:29.961592-05:
      DOI: 10.1002/adfm.201670122
       
 
 
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