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  Subjects -> CHEMISTRY (Total: 844 journals)
    - ANALYTICAL CHEMISTRY (51 journals)
    - CHEMISTRY (594 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (25 journals)
    - INORGANIC CHEMISTRY (41 journals)
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    - PHYSICAL CHEMISTRY (67 journals)

CHEMISTRY (594 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
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: 34)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 24)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 244)
ACS Photonics     Full-text available via subscription   (Followers: 12)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 23)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chimica Slovenica     Open Access  
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 8)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 51)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 56)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 15)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 21)
Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 66)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 15)
American Journal of Chemistry     Open Access   (Followers: 27)
American Journal of Plant Physiology     Open Access   (Followers: 14)
American Mineralogist     Hybrid Journal   (Followers: 14)
Analyst     Full-text available via subscription   (Followers: 40)
Angewandte Chemie     Hybrid Journal   (Followers: 225)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 222)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 16)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 313)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 121)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 89)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 66)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 7)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 8)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 15)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 72)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 25)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 20)
Chemical Reviews     Full-text available via subscription   (Followers: 179)
Chemical Science     Open Access   (Followers: 22)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 58)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 26)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 151)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 20)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Materials     Full-text available via subscription   (Followers: 227)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 4)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
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: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 3)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 17)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 62)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
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: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 3)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 3)

        1 2 3 | Last

Journal Cover Advanced Functional Materials
  [SJR: 5.21]   [H-I: 203]   [51 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  [1589 journals]
  • Pt Nanoparticles Sensitized Ordered Mesoporous WO3 Semiconductor: Gas
           Sensing Performance and Mechanism Study
    • Authors: Junhao Ma; Yuan Ren, Xinran Zhou, Liangliang Liu, Yongheng Zhu, Xiaowei Cheng, Pengcheng Xu, Xinxin Li, Yonghui Deng, Dongyuan Zhao
      Abstract: In this study, a straightforward coassembly strategy is demonstrated to synthesize Pt sensitized mesoporous WO3 with crystalline framework through the simultaneous coassembly of amphiphilic poly(ethylene oxide)-b-polystyrene, hydrophobic platinum precursors, and hydrophilic tungsten precursors. The obtained WO3/Pt nanocomposites possess large pore size (≈13 nm), high surface area (128 m2 g−1), large pore volume (0.32 cm3 g−1), and Pt nanoparticles (≈4 nm) in situ homogeneously distributed in mesopores, and they exhibit excellent catalytic sensing response to CO of low concentration at low working temperature with good sensitivity, ultrashort response-recovery time (16 s/1 s), and high selectivity. In-depth study reveals that besides the contribution from the fast diffusion of gaseous molecules and rich interfaces in mesoporous WO3/Pt nanocomposites, the partially oxidized Pt nanoparticles that chemically and electronically sensitize the crystalline WO3 matrix, dramatically enhance the sensitivity and selectivity.Ordered mesoporous crystalline WO3/Pt nanomaterials are synthesized through a facile straightforward coassembly strategy. Owning to combined merits of the high porosity of mesoporous WO3 and the chemical and electronic sensitization effect of Pt NPs dispersed in mesopores, the nanocomposites exhibit superior performance in carbon monoxide sensing at low working temperature.
      PubDate: 2017-12-11T05:37:22.564525-05:
      DOI: 10.1002/adfm.201705268
       
  • Toward Stretchable Self-Powered Sensors Based on the Thermoelectric
           Response of PEDOT:PSS/Polyurethane Blends
    • Authors: Prospero J. Taroni; Giovanni Santagiuliana, Kening Wan, Philip Calado, Manting Qiu, Han Zhang, Nicola M. Pugno, Matteo Palma, Natalie Stingelin-Stutzman, Martin Heeney, Oliver Fenwick, Mark Baxendale, Emiliano Bilotti
      Abstract: The development of new flexible and stretchable sensors addresses the demands of upcoming application fields like internet-of-things, soft robotics, and health/structure monitoring. However, finding a reliable and robust power source to operate these devices, particularly in off-the-grid, maintenance-free applications, still poses a great challenge. The exploitation of ubiquitous temperature gradients, as the source of energy, can become a practical solution, since the recent discovery of the outstanding thermoelectric properties of a conductive polymer, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). Unfortunately the use of PEDOT:PSS is currently constrained by its brittleness and limited processability. Herein, PEDOT:PSS is blended with a commercial elastomeric polyurethane (Lycra), to obtain tough and processable self-standing films. A remarkable strain-at-break of ≈700% is achieved for blends with 90 wt% Lycra, after ethylene glycol treatment, without affecting the Seebeck voltage. For the first time the viability of these novel blends as stretchable self-powered sensors is demonstrated.Stretchable self-powered sensors are developed via blending elastomeric polyurethane (Lycra) with the best current organic thermoelectric material, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). In doing so, the main technological constrains of PEDOT:PSS, namely brittleness, processability, and costs, have, at the same time, been overcome. An unprecedented strain at break (≈700%) is reached, while maintaining high electrical conductivity (≈79 S cm−1) and Seebeck coefficient (≈16 µV K−1).
      PubDate: 2017-12-11T05:14:43.080671-05:
      DOI: 10.1002/adfm.201704285
       
  • Reversible Thermochromic Polymeric Thin Films Made of Ultrathin 2D
           Crystals of Coordination Polymers Based on Copper(I)-Thiophenolates
    • Authors: Javier Troyano; Oscar Castillo, José I. Martínez, Vanesa Fernández-Moreira, Yolanda Ballesteros, Daniel Maspoch, Félix Zamora, Salome Delgado
      Abstract: A one-pot reaction between Cu(BF4)2·xH2O and 4-mercaptobenzoic acid in acetone or methanol gives rise to the formation of lamellar microcrystals of two Cu(I)-thiophenolate-based coordination polymers (CPs) with the formulas [CuCT]n (1) (CT = 4-carboxy-thiophenolate) and [CuMCT]n (2) (MCT = 4-methoxycarbonyl-thiophenolate). Both 1 and 2 show a reversible luminescent thermochromic behavior upon cooling, changing their color from pale yellow to green to orange in the case of 1, and from pale orange to green in the case of 2. It is shown that the lamellar character of these crystals, which exhibit micrometer lateral dimensions and sub-micrometer/nanometer thicknesses, allows processing them with an organic polymer such as polyvinylidene difluoride (PVDF) to form thermochromic 1@PVDF and 2@PVDF thin films. These thermal stimuli-responsive thin films are freestanding, free of macroscopic defects, and robust under mechanical bending stress, opening up the possibility to use them in, for example, 2D imaging sensor films.Fabrication of reversible thermochromic composite thin films has been achieved by integration of crystalline 2D crystals of coordination polymers, which exhibit micrometer lateral dimensions and sub-micrometer/nanometer thicknesses allowing an efficient dispersibility in polyvinylidene difluoride. These thermal stimuli-responsive composite thin films are flexible, freestanding, free of macroscopic defects, and robust under mechanical bending stress.
      PubDate: 2017-12-11T05:13:50.258066-05:
      DOI: 10.1002/adfm.201704040
       
  • Electrically Controlled Neurochemical Release from Dual-Layer Conducting
           Polymer Films for Precise Modulation of Neural Network Activity in Rat
           Barrel Cortex
    • Authors: Zhanhong Jeff Du; Guo-Qiang Bi, Xinyan Tracy Cui
      Abstract: Implantable microelectrode arrays (MEAs) are important tools for investigating functional neural circuits and treating neurological diseases. Precise modulation of neural activity may be achieved by controlled delivery of neurochemicals directly from coatings on MEA electrode sites. In this study, a novel dual-layer conductive polymer/acid functionalized carbon nanotube (fCNT) microelectrode coating is developed to better facilitate the loading and controlled delivery of the neurochemical 6,7-dinitroquinoxaline-2,3-dione (DNQX). The base layer coating is consisted of poly(3,4-ethylenedioxythiophene/fCNT and the top layer is consisted of polypyrrole/fCNT/DNQX. The dual-layer coating is capable of both loading and electrically releasing DNQX and the release dynamic is characterized with fluorescence microscopy and mathematical modeling. In vivo DNQX release is demonstrated in rat somatosensory cortex. Sensory-evoked neural activity is immediately (
      PubDate: 2017-12-11T05:12:41.637336-05:
      DOI: 10.1002/adfm.201703988
       
  • Bipolar Conducting Polymer Crawlers Based on Triple Symmetry Breaking
    • Authors: Bhavana Gupta; Bertrand Goudeau, Patrick Garrigue, Alexander Kuhn
      Abstract: Bipolar electrochemistry can be used in different ways to induce motion of an object, for example by generating gas bubbles in an asymmetric way or by a wireless self-regeneration mechanism due to the intrinsic symmetry breaking of this concept. Here a complementary approach is explored on the basis of conducting polymer objects addressed in solution by an electric field. The presence of the latter results in a differential polarization of the polymer, thus enabling its oxidation at one extremity and its reduction at the opposite side. This triggers different degrees of swelling and shrinking, leading to important deformations of the object. Combined with an additional asymmetry in the polymer surface morphology, a periodic switching of the electric field orientation allows exploiting these deformations to induce directed crawling motion. This first example of a wireless biomimetic crawler based on conducting polymers opens interesting long-term perspectives in several areas such as for example wireless valves, pumps and (micro)robotics.Bipolar electrochemistry is used to induce directed crawling of conducting polymer strips without requiring a physical contact to a power supply. The concept is based on an intrinsic triple symmetry breaking due to differential changes in morphology. This type of wireless locomotion of conducting polymers opens interesting perspectives in the field of (micro)robotics.
      PubDate: 2017-12-11T05:11:37.868043-05:
      DOI: 10.1002/adfm.201705825
       
  • In Situ Separation of Chemical Reaction Systems Based on a Special
           Wettable PTFE Membrane
    • Authors: Zhe Xu; Li Wang, Cunming Yu, Kan Li, Ye Tian, Lei Jiang
      Abstract: Oil–water separation is a worldwide subject because of the increasing demands in numerous applications, involving separation of immiscible products from chemical reaction systems in synthetic industry. Owing to the limitations of low efficiency, high energy consumption, and multiple operations in conventional methods, membranes with special wettability have been widely developed in recent years to effectively separate various oil–water systems. However, few works on treating chemical reaction systems have been reported because of the lack of stability of current membranes in harsh environments, especially during long-term work. Herein, a continuous in situ separation of chemical reaction systems based on a special wettable porous polytetrafluoroethylene membrane is successfully conducted. The membrane possesses (1) an intrinsic (with no modification) special wettability of highly hydrophobic/oleophilic in air and superoleophilic under water and 2) an excellent long-term durability in acidic, alkaline, saline, organic, or heating environments. The in situ separation process exhibits both large separation flux (>3500 L m−2 h−1) and high product purity (>99.00%) by continuously filtering synthetic products without interrupting chemical reactions, which is of great significance in industrial fields.A polytetrafluoroethylene microporous membrane with an intrinsic special wettability of highly hydrophobic/oleophilic in air and superoleophilic under water is directly obtained by laser fabrication. The membrane possesses an excellent durability even in harsh environments. Using the functional membrane, continuous in situ separation of chemical reaction systems is conducted for the first time, with large separation flux and high product purity.
      PubDate: 2017-12-11T05:10:03.246074-05:
      DOI: 10.1002/adfm.201703970
       
  • Achieving an Efficiency Exceeding 10% for Fullerene-based Polymer Solar
           Cells Employing a Thick Active Layer via Tuning Molecular Weight
    • Authors: Zelin Li; Dalei Yang, Xiaoli Zhao, Tong Zhang, Jidong Zhang, Xiaoniu Yang
      Abstract: Recently, the influence of molecular weight (Mn) on the performance of polymer solar cells (PSCs) is widely investigated. However, the dependence of optimal thickness of active layer for PSCs on Mn is not reported yet, which is vital to the solution printing technology. In this work, the effect of Mn on the efficiency and especially optimal thickness of the active layer for PBTIBDTT-S-based PSCs is systematically studied. The device efficiency improves significantly as the Mn increases from 12 to 38 kDa, and a remarkable efficiency of 10.1% is achieved, which is among the top efficiencies of wide-bandgap polymer:fullerene PSCs. Furthermore, the optimal thickness of the active layer is also greatly increased from 62 to 210 nm with increased Mn. Therefore, a device employing a thick (>200 nm) active layer with power conversion efficiency exceeding 10% is achieved by manipulating Mn. This exciting result is attributed to both the improved crystallinity, thus hole mobility, and preferable polymer orientation, thus morphology of active layer. These findings, for the first time, highlight the significant impact of Mn on the optimal thickness of active layer for PSCs and provide a facile way to further improve the performance of PSCs employing a thick active layer.As the molecular weight (Mn) of PBTIBDTT-S increases from 12 to 38 kDa, the efficiency and optimal thickness of the active layer are simultaneously improved from 6.99% to 10.11% and from 62 to 210 nm, respectively. This result demonstrates the importance of Mn in achieving highly efficient devices under a thick active layer.
      PubDate: 2017-12-11T05:06:11.083129-05:
      DOI: 10.1002/adfm.201705257
       
  • Effects of Nonradiative Losses at Charge Transfer States and Energetic
           Disorder on the Open-Circuit Voltage in Nonfullerene Organic Solar Cells
    • Authors: Shenkun Xie; Yuxin Xia, Zhong Zheng, Xuning Zhang, Jianyu Yuan, Huiqiong Zhou, Yuan Zhang
      Abstract: The considerable improvement on the power conversion efficiency (PCE) for emerging nonfullerene polymer solar cells is still limited by considerable voltage losses that have become one of the most significant obstacles in further boosting desired photovoltaic performance. Here, a comprehensive study is reported to understand the impacts of charge transport, energetic disorder, and charge transfer states (CTS) on the losses in open-circuit voltage (Voc) based on three high performing bulk heterojunction solar cells with the best PCE exceeding 11%. It is found that the champion poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene)-co-(1,3-di(5-thiophene-2-yl)-5,7-bis(2-ethylhexyl)-benzo[1,2-c:4,5-c′]dithiophene-4,8-dione))] (PBDB-T):IT-M solar cell (PCE = 11.5%) is associated with the least disorder. The determined energetic disorder in part reconciles the difference in Voc between the solar cells. A reduction is observed in the nonradiative losses (ΔVnonrad) coupled with the increase of energy of CTS for the PBDB-T:IT-M device, which may be related to the improved balance in carrier mobilities, and partially can explain the gain in Voc. The determined radiative limit for Voc combined with the ΔVnonrad generates an excellent agreement for the Voc with the experimental values. The results suggest that minimizing the energetic disorder related to transport and CTS is critical for the mitigation of Voc losses and improvements on the device performance.Voltage losses and charge transport in three representative bulk heterojunction solar cells are investigated. By temperature-dependent open-circuit voltage (Voc) analysis and photovoltaic electroluminescence spectroscopy, we find that the increased Voc in the champion IT-M cell with an excellent balance in mobility is associated with reduced energetic disorder at the D/A interface and non-redative recombination losses at charge transfer states.
      PubDate: 2017-12-11T05:04:39.723134-05:
      DOI: 10.1002/adfm.201705659
       
  • Simultaneous Activation of Short-Wave Infrared (SWIR) Light and
           Paramagnetism by a Functionalized Shell for High Penetration and Spatial
           Resolution Theranostics
    • Authors: Liyi Ma; Yuxin Liu, Lidong Liu, Anqi Jiang, Fang Mao, Dongdong Liu, Lu Wang, Jing Zhou
      Abstract: Nanoparticle emitting short-wave infrared (SWIR) light has received increased attention in the molecular imaging field due to its deeper tissue penetration, fast imaging, high sensitivity, and resolution. The simultaneously activated SWIR excited directly by an 808 nm laser and T1-weighted magnetic resonance imaging (MRI) signal are found in one single-shell nanoparticle NaErF4@NaGdF4 (Er@Gd), which is used as a dual-modality imaging contrast agent in vivo to accurately determine the position of tumors. The conjugated cypate is then aggregated on the surface of Er@Gd@SiO2-Cy/bovine serum albumin. With the guidance of dual modality imaging, photothermal therapy is effectively used to ablate tumors in a mouse model. The design of single-shell nanomaterial activation of SWIR imaging and MRI signals is expected to provide a new strategy for high penetration and spatial resolution cancer theranostics.This elaborate design of the synthesized nanomaterial, NaErF4@NaGdF4@SiO2-Cy/bovine serum albumin, is successful in activating simultaneously short-wave infrared imaging excited directly by a 808 nm laser and T1-weighted magnetic resonance imaging to guide the photothermal therapy of tumors in mice with negligible toxicity, which is proved in this work, and is expected to lead to a better way of high penetration and resolution theranostic in diseases.
      PubDate: 2017-12-11T05:03:34.850114-05:
      DOI: 10.1002/adfm.201705057
       
  • Microcavity Structure Provides High-Performance (>8.1%) Semitransparent
           and Colorful Organic Photovoltaics
    • Authors: Jong-Hong Lu; Yi-Hung Lin, Bing-Huang Jiang, Chun-Hung Yeh, Jui-Chih Kao, Chih-Ping Chen
      Abstract: High-performance colored aesthetic semitransparent organic photovoltaics (OPVs) featuring a silver/indium tin oxide/silver (Ag/ITO/Ag) microcavity structure are prepared. By precisely controlling the thickness of the ITO layer, OPV devices exhibiting high transparency and a wide and high-purity color gamut are obtained: blue (B), green (G), yellow-green (YG), yellow (Y), orange (O), and red (R). The power conversion efficiencies (PCEs) of the G, YG, and Y color devices are greater than 8% (AM 1.5G irradiation, 100 mW cm−2) with maximum transmittances (TMAX) of greater than 14.5%. An optimized PCE of 8.2% was obtained for the YG OPV [CIE 1931 coordinates: (0.364, 0.542)], with a value of TMAX of 17.3% (at 561 nm). As far as it is known, this performance is the highest ever reported for a transparent colorful OPV. Such high transparency and desired transmitted colors, which can perspective see the clear images, suggest great potential for use in building-integrated photovoltaic applications.High-performance colored aesthetic semitransparent organic photovoltaics (OPVs) featuring a silver/indium tin oxide/silver microcavity structure are demonstrated. Colored OPVs of high purity and a wide color gamut are obtained: blue, green, yellow-green, yellow, orange, and red. The highest power conversion efficiency was 8.2% for the yellow-green device, with CIE 1931 coordinates of (0.364, 0.542) and a transmittance of 17.3% at 561 nm.
      PubDate: 2017-12-08T05:51:42.639715-05:
      DOI: 10.1002/adfm.201703398
       
  • Band Structure and Photoelectric Characterization of GeSe Monolayers
    • Authors: Hongquan Zhao; Yuliang Mao, Xin Mao, Xuan Shi, Congshen Xu, Chunxiang Wang, Shangmin Zhang, Dahua Zhou
      Abstract: Germanium selenide monolayer is promising in photoelectric applications for its natural p-type semiconductor and complicated band structures. Basic experimental investigations of few-to-monolayer germanium selenide are still absent; major scientific challenge is to develop of techniques for controllably thinned monolayers. In this study laser thinned monolayer germanium selenide on SiO2/Si substrates is demonstrated. A broad photoluminescence spectrum with eight continues peaks is observed from visible to infrared wavebands centered at ≈589, 655, 737, 830, 1034, 1178, 1314, and 1456 nm, respectively. First-principle calculations based on density functional theory illuminate the band structures of few-to-monolayer germanium selenide. Photoluminescence investigation combined with first-principle calculations indicates that the indirect to direct bandgap transition happens at few layers of N = 3. Current–voltage and photoresponse characteristics of monolayer based devices show 3.3 times the photosensitivity and much faster falling edges compared with those of the pristine nanosheet based devices. The present results provide useful insight into deep understanding of thickness dependent performances of germanium selenide monocrystalline.Monolayer GeSe is demonstrated on SiO2/Si substrates. Photoluminescence combined with first-principle calculations illuminates the band structures of few-to-monolayer GeSe, indicating the indirect to direct bandgap transition happens at few layers of N = 3. I–V and photoresponse of monolayer devices show 3.3 times the photosensitivity and faster falling edges compared with those of the pristine nanosheet devices.
      PubDate: 2017-12-08T05:47:22.501931-05:
      DOI: 10.1002/adfm.201704855
       
  • “Trade-Off” Hidden in Condensed State Solvation: Multiradiative
           Channels Design for Highly Efficient Solution-Processed Purely Organic
           Electroluminescence at High Brightness
    • Authors: Xinyi Cai; Dongjun Chen, Kuo Gao, Lin Gan, Qingwu Yin, Zhenyang Qiao, Zijun Chen, Xiaofang Jiang, Shi-Jian Su
      Abstract: Actualizing highly efficient solution-processed thermally activated delayed fluorescent (TADF) organic light-emitting diodes (OLEDs) at high brightness becomes significant to the popularization of purely organic electroluminescence. Herein, a highly soluble emitter benzene-1,3,5-triyltris((4-(9,9-dimethylacridin-10(9H)-yl)phenyl)methanone was developed, yielding high delayed fluorescence rate (kTADF> 105 s−1) ascribed to the multitransition channels and tiny singlet–triplet splitting energy (ΔEST ≈ 32.7 meV). The triplet locally excited state is 0.38 eV above the lowest triplet charge-transfer state, assuring a solely thermal equilibrium route for reverse intersystem crossing. Condensed state solvation effect unveils a hidden “trade-off”: the reverse upconversion and triplet concentration quenching processes can be promoted but with a reduced radiative rate from the increased dopant concentration and the more polarized surroundings. Striking a delicate balance, corresponding vacuum-evaporated and solution-processed TADF-OLEDs realized maximum external quantum efficiencies (EQEs) of ≈26% and ≈22% with extremely suppressed efficiency roll-off. Notably, the wet-processed one achieves to date the highest EQEs of 20.7%, 18.5%, 17.1%, and 13.6%, among its counterparts at the luminance of 1000, 3000, 5000, and 10 000 cd m−2, respectively.Hidden “trade-off” among highly radiative rate, rapid reverse upconversion, and suppressed concentration quenching is reached by condensed state solvation. With multitransition channels design for thermally activated delayed fluorescence rate surpassing 105 s−1, solution-processed organic light-emitting diodes achieve to date the best external quantum efficiencies at very high brightness (1000–10 000 cd m−2) among wet-processed purely organic electroluminescent devices.
      PubDate: 2017-12-08T05:46:25.054198-05:
      DOI: 10.1002/adfm.201704927
       
  • Yolk–Shell Structured Assembly of Bamboo-Like Nitrogen-Doped Carbon
           Nanotubes Embedded with Co Nanocrystals and Their Application as Cathode
           Material for Li–S Batteries
    • Authors: Seung-Keun Park; Jung-Kul Lee, Yun Chan Kang
      Abstract: Despite their high theoretical specific capacity (1675 mA h g−1), the practical application of Li–S batteries remains limited because the capacity rapidly degrades through severe dissolution of lithium polysulfide and the rate capability is low because of the low electronic conductivity of sulfur. This paper describes novel hierarchical yolk–shell microspheres comprising 1D bamboo-like N-doped carbon nanotubes (CNTs) encapsulating Co nanoparticles (Co@BNCNTs YS microspheres) as efficient cathode hosts for Li–S batteries. The microspheres are produced via a two-step process that involves generation of the microsphere followed by N-doped CNTs growth. The hierarchical yolk–shell structure enables efficient sulfur loading and mitigates the dissolution of lithium polysulfides, and metallic Co and N doping improves the chemical affinity of the microspheres with sulfur species. Accordingly, a Co@BNCNTs YS microsphere-based cathode containing 64 wt% sulfur exhibits a high discharge capacity of 700.2 mA h g−1 after 400 cycles at a current density of 1 C (based on the mass of sulfur); this corresponds to a good capacity retention of 76% and capacity fading rate of 0.06% per cycle with an excellent rate performance (752 mA h g−1 at 2.0 C) when applied as cathode hosts for Li–S batteries.Hierarchical yolk–shell microspheres comprising 1D bamboo-like N-doped carbon nanotubes (CNTs) encapsulating Co nanocrystals are first introduced as efficient cathode hosts for Li–S batteries. The synergetic effect of the presence of the N-doped CNTs with Co nanocrystals and the hierarchical structure of yolk-shell microspheres is responsible for the superior performances as the cathode hosts for Li–S batteries.
      PubDate: 2017-12-08T05:41:26.578851-05:
      DOI: 10.1002/adfm.201705264
       
  • Self-Healing Shape Memory PUPCL Copolymer with High Cycle Life
    • Authors: Hafeez Ur Rehman; Yujie Chen, Mikael S. Hedenqvist, Hua Li, Wenchao Xue, Yunlong Guo, Yiping Guo, Huanan Duan, Hezhou Liu
      Abstract: New polyurethane-based polycaprolactone copolymer networks, with shape recovery properties, are presented here. Once deformed at ambient temperature, they show 100% shape fixation until heated above the melting point, where they recover the initial shape within 22 s. In contrast to current shape memory materials, the new materials do not require deformation at elevated temperature. The stable polymer structure of polyurethane yields a copolymer network that has strength of 10 MPa with an elongation at break of 35%. The copolymer networks are self-healing at a slightly elevated temperature (70 °C) without any external force, which is required for existing self-healing materials. This allows for the new materials to have a long life of repeated healing cycles. The presented copolymers show features that are promising for applications as temperature sensors and activating elements.New polyurethane-based polycaprolactone copolymer networks are presented here. The TOC image shows the representative high cycle shape recovery phenomenon at a temperature higher than Tc or Tm of the material after 100% shape fixation with potential applications into actuating elements and artificial muscles while lifting a heavier weight 20 times the weight of copolymer networks.
      PubDate: 2017-12-07T06:07:40.725316-05:
      DOI: 10.1002/adfm.201704109
       
  • Nanoformulation of Brain-Derived Neurotrophic Factor with Target
           Receptor-Triggered-Release in the Central Nervous System
    • Authors: Yuhang Jiang; James M. Fay, Chi-Duen Poon, Natasha Vinod, Yuling Zhao, Kristin Bullock, Si Qin, Devika S Manickam, Xiang Yi, William A. Banks, Alexander V. Kabanov
      Abstract: Brain-derived neurotrophic factor (BDNF) is identified as a potent neuroprotective and neuroregenerative agent for many neurological diseases. Regrettably, its delivery to the brain is hampered by poor serum stability and rapid brain clearance. Here, a novel nanoformulation is reported composed of a biocompatible polymer, poly(ethylene glycol)-b-poly(l-glutamic acid) (PEG-PLE), that hosts the BDNF molecule in a nanoscale complex, termed here Nano-BDNF. Upon simple mixture, Nano-BDNF spontaneously forms uniform spherical particles with a core–shell structure. Molecular dynamics simulations suggest that binding between BDNF and PEG-PLE is mediated through electrostatic coupling as well as transient hydrogen bonding. The formation of Nano-BDNF complex stabilizes BDNF and protects it from nonspecific binding with common proteins in the body fluid, while allowing it to associate with its receptors. Following intranasal administration, the nanoformulation improves BDNF delivery throughout the brain and displays a more preferable regional distribution pattern than the native protein. Furthermore, intranasally delivered Nano-BDNF results in superior neuroprotective effects in the mouse brain with lipopolysaccharides-induced inflammation, indicating promise for further evaluation of this agent for the therapy of neurologic diseases.A self-assembled nanoformulation delivers active brain-derived neurotrophic factor (BDNF) to the central nervous system via the intranasal-to-brain pathway. The polyion complex formed by electrostatic interactions between BDNF and poly(ethylene glycol)-b-poly(l-glutamic acid) stabilizes the protein and delivers it to the brain at significantly higher rates than the native protein, and releases BDNF exclusively to its receptors upon contact.
      PubDate: 2017-12-07T06:05:06.329128-05:
      DOI: 10.1002/adfm.201703982
       
  • Malonitrile-Functionalized Tetraphenylpyrazine: Aggregation-Induced
           Emission, Ratiometric Detection of Hydrogen Sulfide, and Mechanochromism
    • Authors: Ming Chen; Rui Chen, Yang Shi, Jianguo Wang, Yanhua Cheng, Ying Li, Xuedong Gao, Yun Yan, Jing Zhi Sun, Anjun Qin, Ryan T. K. Kwok, Jacky W. Y. Lam, Ben Zhong Tang
      Abstract: Development of new aggregation-induced emission (AIE) luminogens has been a hot research topic because they thoroughly solve the notorious aggregation-caused quenching effect confronted in conventional fluorogens and their promising applications in, for example, organic light-emitting diodes, chemo- and biosensors and bioimaging. Many AIE luminogens (AIEgens) have been prepared but most of them are silole, tetraphenylethene, distyrylanthracene, and their derivatives. In this work, based on the skeleton of tetraphenylpyrazine (TPP), a new AIEgen, named TPP-PDCV, is generated by functionalizing TPP with malonitrile group. TPP-PDCV can serve as a sensitive ratiometric fluorescent probe for detecting hydrogen sulfide with high speciality and low detection limit of down to 0.5 × 10−6m. The mechanism for such detection is fully investigated and deciphered. Unlike most reported mechanochromic AIEgens, which undergo turn-off or -on emission or emission bathochromic shift in the presence of external stimuli, TPP-PDCV exhibits an abnormal and reversible mechanochromism with hypsochromic effect. These indicate that TPP-PDCV possesses a huge potential for high-tech applications through rational modification of TPP core.A tetraphenylpyrazine-based aggregation-induced emission luminogen (AIEgen) with malonitrile functionality can function as a ratiometric fluorescent probe to detect hydrogen sulfide with fast response, high sensitivity, and good selectivity. It also displays a reversible mechanochromism with a hypsochromic effect in the presence of external stimuli, which is rarely observed in previously reported AIEgens.
      PubDate: 2017-12-07T06:04:13.270606-05:
      DOI: 10.1002/adfm.201704689
       
  • Simultaneously Achieved High Open-Circuit Voltage and Efficient Charge
           Generation by Fine-Tuning Charge-Transfer Driving Force in Nonfullerene
           Polymer Solar Cells
    • Authors: Ailing Tang; Bo Xiao, Yuming Wang, Feng Gao, Keisuke Tajima, Haijun Bin, Zhi-Guo Zhang, Yongfang Li, Zhixiang Wei, Erjun Zhou
      Abstract: To maximize the short-circuit current density (JSC) and the open circuit voltage (VOC) simultaneously is a highly important but challenging issue in organic solar cells (OSCs). In this study, a benzotriazole-based p-type polymer (J61) and three benzotriazole-based nonfullerene small molecule acceptors (BTA1-3) are chosen to investigate the energetic driving force for the efficient charge transfer. The lowest unoccupied molecular orbital (LUMO) energy levels of small molecule acceptors can be fine-tuned by modifying the end-capping units, leading to high VOC (1.15–1.30 V) of OSCs. Particularly, the LUMO energy level of BTA3 satisfies the criteria for efficient charge generation, which results in a high VOC of 1.15 V, nearly 65% external quantum efficiency, and a high power conversion efficiency (PCE) of 8.25%. This is one of the highest VOC in the high-performance OSCs reported to date. The results imply that it is promising to achieve both high JSC and VOC to realize high PCE with the carefully designed nonfullerene acceptors.The existence of the driving force in organic solar cells (OSCs) often creates a problematic trade-off between the open-circuit voltage and short-circuit current. Here, fine-tuning driving force by gradually decreasing the acceptor energy level has afforded high open-circuit voltage (>1.15 V) and efficient charge generation (>60%) at the same time, which is instructive to the development of more efficient OSCs.
      PubDate: 2017-12-07T06:03:22.132909-05:
      DOI: 10.1002/adfm.201704507
       
  • Colossal X-Ray-Induced Persistent Photoconductivity in
           Current-Perpendicular-to-Plane Ferroelectric/Semiconductor Junctions
    • Authors: Wei Jin Hu; Tula R. Paudel, Sergei Lopatin, Zhihong Wang, He Ma, Kewei Wu, Ashok Bera, Guoliang Yuan, Alexei Gruverman, Evgeny Y. Tsymbal, Tom Wu
      Abstract: Persistent photoconductivity (PPC) is an intriguing physical phenomenon, where electric conduction is retained after the termination of electromagnetic radiation, which makes it appealing for applications in a wide range of optoelectronic devices. So far, PPC has been observed in bulk materials and thin-film structures, where the current flows in the plane, limiting the magnitude of the effect. Here using epitaxial Nb:SrTiO3/Sm0.1Bi0.9FeO3/Pt junctions with a current-perpendicular-to-plane geometry, a colossal X-ray-induced PPC (XPPC) is achieved with a magnitude of six orders. This PPC persists for days with negligible decay. Furthermore, the pristine insulating state could be fully recovered by thermal annealing for a few minutes. Based on the electric transport and microstructure analysis, this colossal XPPC effect is attributed to the X-ray-induced formation and ionization of oxygen vacancies, which drives nonvolatile modification of atomic configurations and results in the reduction of interfacial Schottky barriers. This mechanism differs from the conventional mechanism of photon-enhanced carrier density/mobility in the current-in-plane structures. With their persistent nature, such ferroelectric/semiconductor heterojunctions open a new route toward X-ray sensing and imaging applications.Using a ferroelectric/semiconductor heterojunction of Nb doped SrTiO3/Sm0.1Bi0.9FeO3, a colossal persistent photoconductivity in the current-perpendicular-to-plane junction geometry is reported. Conceptually different from the current-in-plane devices, where the persistent photoconductivity occurs due to the modulation of carrier density/mobility, the colossal effect observed here originates from the X-ray induced modulation of the interfacial barrier.
      PubDate: 2017-12-07T06:01:27.583439-05:
      DOI: 10.1002/adfm.201704337
       
  • Improving and Predicting Fluid Atomization via Hysteresis-Free Thickness
           Vibration of Lithium Niobate
    • Authors: Sean Collignon; Ofer Manor, James Friend
      Abstract: Acoustically driven atomization from the broad perspective of materials choice, vibration mode, and fluid characteristics is considered to identify a simple method for improving both the understanding of the atomization phenomena and the overall efficiency of atomization. Whether by the definition of a “figure of merit” (a function of the transducer quality factor and electromechanical coupling coefficient), its output vibration displacement at a given input power, or the fluid flow rate during atomization, it is found that the combination of single-crystal 127.86° Y-rotated lithium niobate and thickness-mode vibration produces an order of magnitude greater atomization flow rate and efficiency in comparison to all known atomizers, including classic lead zirconate-based devices and newer, Rayleigh wave or Rayleigh/Lamb spurious-mode-based devices alike. By using this improved approach, for the first time, fluids with viscosities up to 48 cP are reported to be atomized, and an atomization Reynolds number ReA is defined which can be used to both predict the atomization flow rate for ReA ≳ 40 and the inability to atomize a given fluid at a particular vibration amplitude when ReA ≲ 40.Through careful consideration of the materials and vibration in piezoelectric media, a counterintuitively superior method is discovered for efficiently and quickly atomizing even viscous fluids from a handheld nebulizer. Using a “figure of merit” defined in terms of the piezoelectric materials and vibration mode, the thickness mode in lithium niobate is found to offer superior atomizer capabilities.
      PubDate: 2017-12-07T05:59:21.813981-05:
      DOI: 10.1002/adfm.201704359
       
  • Self-Powered Noncontact Electronic Skin for Motion Sensing
    • Authors: Hanxiang Wu; Zongming Su, Mayue Shi, Liming Miao, Yu Song, Haotian Chen, Mengdi Han, Haixia Zhang
      Abstract: The advancement of electronic skin envisions novel multifunctional human machine interfaces. Although motion sensing by detecting contact locations is popular and widely used in state-of-the-art flexible electronics, noncontact localization exerts fascinations with unique interacting experiences. This paper presents a self-powered noncontact electronic skin capable of detecting the motion of a surface electrified object across the plane parallel to that of the electronic skin based on electrostatic induction and triboelectric effects. The displacement of the object is calculated under the system of polar coordinates, with a resolution of 1.5 mm in the lengthwise direction and 0.76° in the angular direction. It can serve as a human machine interface due to its ability to sense noncontact motions. An additional self-powered feature, enabled by its physical principles, solves the problem of power supply. This electronic skin consists of trilayers of polyethyleneterephthalate–indium tin oxide–polydimethylsiloxane (PDMS) films, and microstructured PDMS as the electrified layer, which can be achieved through simplified, low cost, and scalable fabrication. Transparency, flexibility, and less number of electrodes enable such electronic skin to be easily integrated into portable electronic devices, such as laptops, smart phones, healthcare devices, etc.This paper presents a self-powered noncontact electronic skin for motion sensing, which can serve as a human–machine interface. An additional self-powered feature solves the problem of power supply. Its fabrication process is achieved through simplified, low cost, and scalable fabrication. Transparency, flexibility, and less number of electrodes enable such electronic skin to be easily integrated into portable electronic devices.
      PubDate: 2017-12-07T05:58:59.83526-05:0
      DOI: 10.1002/adfm.201704641
       
  • Evaluating the Role of Nanostructured Current Collectors in Energy Storage
           Capability of Supercapacitor Electrodes with Thick Electroactive Materials
           Layers
    • Authors: Long Liu; Huaping Zhao, Yi Wang, Yaoguo Fang, Jiale Xie, Yong Lei
      Abstract: Electroactive materials (especially pseudocapacitive materials) are generally in the form of ultrathin conformal coating in supercapacitor electrodes based on nanostructured current collectors; thus, the resultant low mass loading of electroactive materials largely limits the applications of nanostructured current collectors. Here, supercapacitor electrodes with nickel nanorod arrays as nanostructured current collectors and MnO2 as electroactive materials are fabricated to study the role of nanostructured current collectors in determining the energy storage capability when electroactive materials are in thick layer rather than ultrathin conformal coating. Electrochemical analysis reveals that Ni nanorods could create numerous electrical conductive tunnels in the thick-layer electrodes to dramatically alleviate the contact resistance at the electroactive-material/current-collector interface. With 1 µm thick MnO2 layer, the Ni nanorods based electrodes have much higher areal capacitance than those with Ni foils as current collectors, which is more than six times of that with the same MnO2 mass loading or more than 18 times of that with the same 1 µm thick MnO2 layer. Moreover, better rate capability and higher structural stability is maintained in Ni nanorods based electrodes even with 3 µm thick MnO2 layer. These results open up new opportunities for nanostructured current collectors to construct supercapacitors with superior energy storage capability.Nanostructured current collectors in supercapacitor electrodes with thick-layer electroactive materials could significantly increase the contact spots at the electroactive-material/current-collector interfaces, then the interfacial resistance and equivalent series resistance in supercapacitor electrodes are successfully reduced, and finally resulting in superior energy storage capability of supercapacitors.
      PubDate: 2017-12-07T05:54:53.038059-05:
      DOI: 10.1002/adfm.201705107
       
  • Porphyrin/SiO2/Cp*Rh(bpy)Cl Hybrid Nanoparticles Mimicking Chloroplast
           with Enhanced Electronic Energy Transfer for Biocatalyzed Artificial
           Photosynthesis
    • Authors: Xiaoyuan Ji; Jie Wang, Lin Mei, Wei Tao, Austin Barrett, Zhiguo Su, Shaomin Wang, Guanghui Ma, Jinjun Shi, Songping Zhang
      Abstract: A biocatalyzed artificial photosynthesis system (APS) based on porphyrin/SiO2/Cp*Rh(bpy)Cl hybrid nanoparticles (TCPP/SiO2/Rh HNPs) to mimic chloroplasts in green plant is reported. The TCPP/SiO2/Rh HNPs are fabricated via sol–gel reaction of silica precursors functionalized with photosensitizer (porphyrin, TCPP) and electron mediator (Cp*Rh(bpy)Cl, M); while the integration of enzyme and coenzyme nicotinamide adenine dinucleotide (NAD)(H), on the outer surface of the HNPs is achieved through electrostatic-interaction-driven assembling under the entanglement of a negatively charged polyelectrolyte. The chloroplast-mimicking, highly integrated APS exhibits remarkably superior performance over a free system such that the regeneration of NADH is improved from 11% to 75%, and the synthesis of formic acid from CO2 increased from 15 to 100 µmol. Based on the detailed investigations into the photochemical and electrochemical properties, it is speculated that the covalent linking of the photosensitizer and electron mediator via silicon hydride bonds, and the formed SiO2 network through sol–gel reaction, may form intramolecular and intermolecular electron transfer chains to direct more efficient electron transfer from TCPP to M. Such intramolecular and intermolecular electrons and energy transfer, cooperated with the integrated biocatalytic process, lead to the significantly enhanced overall reaction efficiency. Moreover, the integrated APS also allows facile recycling of expensive M, enzymes, and cofactors.A chloroplast-mimicking porphyrin (TCPP)/SiO2/Cp*Rh(bpy)Cl hybrid nanoparticle based artificial photosynthesis system that can efficiently convert CO2 to formic acid under visible-light irradiation is developed by sol–gel reaction with TCPP and electron-mediator-(M) functionalized silica precursors. The intramolecular and intermolecular electron transfer between photosensitizer and M and integration of whole system enable more efficient trafficking of chemicals and electron species between individual active components.
      PubDate: 2017-12-07T05:54:13.541667-05:
      DOI: 10.1002/adfm.201705083
       
  • Light-Harvesting Fluorescent Supramolecular Block Copolymers Based on
           Cyanostilbene Derivatives and Cucurbit[8]urils in Aqueous Solution
    • Authors: Hyeong-Ju Kim; Paramjyothi C. Nandajan, Johannes Gierschner, Soo Young Park
      Abstract: A novel system of light-harvesting supramolecular block copolymers (SBCPs) in water is demonstrated. To realize cucurbit[8]uril (CB[8])-based SBCPs generating artificial light-harvesting in water, finely color-tuned supramolecular homopolymers (SHPs) comprising CB[8] host and different cyanostilbene guests (named as B, G, Y, and R) emitting blue, green, yellow, and red fluorescence are first synthesized and characterized, respectively. Light-harvesting SBCPs with mixed guest emitters are then simply produced by mixing blue and red-emitting SHPs according to the dynamic host–guest exchange interaction. The light-harvesting SBCPs show highly efficient energy transfer from B (donor D) to R (acceptor A) attributed to the D/A proximity and parallel orientation of their transition dipoles secured in the block copolymer structure. It is comprehensively shown that cyanostilbene/CB[8]-based fluorescent SBCPs represent a novel and fascinating class of eco-friendly artificial light-harvesting system.According to the dynamic exchange features of cucurbit[8]uril (CB[8]) hosts and cyanostilbene guests, water-soluble, highly luminescent, and efficiently light-harvesting cyanostilbenes/CB[8]-based supramolecular block copolymer (SBCP) nanobundle systems are successfully materialized. The SBCPs in water show great light-harvesting performance due to energy donor/acceptor proximity and parallel orientation of their transition dipoles secured in the block copolymer structure.
      PubDate: 2017-12-07T05:53:38.388469-05:
      DOI: 10.1002/adfm.201705141
       
  • Carbon Nanotube–Graphitic Carbon Nitride Hybrid Films for
           Flavoenzyme-Catalyzed Photoelectrochemical Cells
    • Authors: Eun Jin Son; Sahng Ha Lee, Su Keun Kuk, Milja Pesic, Da Som Choi, Jong Wan Ko, Kayoung Kim, Frank Hollmann, Chan Beum Park
      Abstract: In green plants, solar-powered electrons are transferred through sophistically arranged photosystems and are subsequently channelled into the Calvin cycle to generate chemical energy. Inspired by the natural photosynthetic scheme, a photoelectrochemical cell (PEC) is constructed configured with protonated graphitic carbon nitride (p-g-C3N4) and carbon nanotube hybrid (CNT/p-g-C3N4) film cathode, and FeOOH-deposited bismuth vanadate (FeOOH/BiVO4) photoanode for the production of industrially useful chiral alkanes using an old yellow enzyme homologue from Thermus scotoductus (TsOYE). In the biocatalytic PEC platform, photoexcited electrons provided by the FeOOH/BiVO4 photoanode are transferred to the robust and self-standing CNT/p-g-C3N4 hybrid film that electrocatalytically reduces flavin mononucleotide (FMN) mediator. The p-g-C3N4 promotes a two-electron reduction of FMN coupled with an accelerated electron transfer by the conductive CNT network. The reduced FMN subsequently delivers the electrons to TsOYE for the highly enantioselective conversion of ketoisophorone to (R)-levodione. Under light illumination (>420 nm) and external bias, (R)-levodione is synthesized with the enantiomeric excess value of above 83%, not influenced by the scale of applied bias, simultaneously exhibiting stable and high current efficiency. The results suggest that the biocatalytic PEC made up of economical materials can selectively synthesize high-value organic chemicals using water as an electron donor.A bioinspired photoelectrochemical cell (PEC) configured with protonated graphitic carbon nitride (p-g-C3N4) and carbon nanotube hybrid (CNT/p-g-C3N4) film cathode, and a FeOOH-deposited bismuth vanadate (FeOOH/BiVO4) photoanode produces alkanes via an old yellow enzyme homologue from Thermus scotoductus. Photoexcited electrons provided by the FeOOH/BiVO4 photoanode are transferred to the robust and self-standing CNT/p-g-C3N4 hybrid film that electrocatalytically reduces a flavin mononucleotide mediator.
      PubDate: 2017-12-07T05:49:51.178958-05:
      DOI: 10.1002/adfm.201705232
       
  • Defect-Rich Ni3FeN Nanocrystals Anchored on N-Doped Graphene for Enhanced
           Electrocatalytic Oxygen Evolution
    • Authors: Shulin Zhao; Meng Li, Min Han, Dongdong Xu, Jing Yang, Yue Lin, Nai-En Shi, Yanan Lu, Rui Yang, Bitao Liu, Zhihui Dai, Jianchun Bao
      Abstract: Owing to their unique optical, electronic, and catalytic properties, metal nitrides nanostructures are widely used in optoelectronics, clean energy, and catalysis fields. Despite great progress has been achieved, synthesis of defect-rich (DR) bimetallic nitride nanocrystals or related nanohybrids remains a challenge, and their electrocatalytic application for oxygen evolution reaction (OER) has not been fully studied. Herein, the DR-Ni3FeN nanocrystals and N-doped graphene (N-G) nanohybrids (DR-Ni3FeN/N-G) are fabricated through temperature-programmed annealing and nitridation treatment of NiFe-layered double hydroxides/graphene oxide precursors by controlling annealing atmosphere. In the nanohybrids, the DR-Ni3FeN nanocrystals are anchored on N-G, and mainly show twin crystal defects besides ≈10% of stacking faults. Such nanohybrids can efficiently catalyze OER in alkaline media with a small overpotential (0.25 V) to attain the current density of 10 mA cm−2 and a high turnover frequency (0.46 s−1), superior to their counterparts (the nearly defect-free Ni3FeN/N-G), commercial IrO2, and the-state-of-art reported OER catalysts. Except for the superior activity, they show better durability than their counterparts yet. As revealed by microstructural, spectroscopic, and electrochemical analyses, the enhanced OER performance of DR-Ni3FeN/N-G nanohybrids originates from the abundant twin crystal defects in Ni3FeN active phase and the strong interplay between DR-Ni3FeN and N-G.Defect-rich Ni3FeN nanocrystals/N-doped graphene (N-G) nanohybrids are synthesized through temperature-programmed annealing and nitridation treatment of NiFe-layered double hydroxide/graphene oxide precursors. Due to the presence of abundant twin crystal defects and the strong interplay of their components, such nanohybrids exhibit greatly enhanced electrocatalytic performance for oxygen evolution, outperforming to their counterparts (nearly defect-free Ni3FeN/N-G), commercial IrO2, and the state-of-the-art reported electrocatalysts.
      PubDate: 2017-12-07T05:41:34.221713-05:
      DOI: 10.1002/adfm.201706018
       
  • Cell Imaging: Photoactive Hybrid AuNR-Pt@Ag2S Core–Satellite
           Nanostructures for Near-Infrared Quantitive Cell Imaging (Adv. Funct.
           Mater. 46/2017)
    • Authors: Aihua Qu; Liguang Xu, Maozhong Sun, Liqiang Liu, Hua Kuang, Chuanlai Xu
      Abstract: A photoactive hybrid nanostructure for near-infrared quantitative cell imaging is reported by Hua Kuang and co-workers in article number 1703408. AuNanorod-PtAgS nanostructures are obtained with high yield. Application of the composite in fluorescent live cell imaging reveals a limit of detection for microRNAs of 0.0082 attomol per ng RNA. This system could provide further inside into the fate of microRNA in live cells.
      PubDate: 2017-12-06T14:15:10.325144-05:
      DOI: 10.1002/adfm.201770273
       
  • Photocatalysis: Effective Prevention of Charge Trapping in Graphitic
           Carbon Nitride with Nanosized Red Phosphorus Modification for Superior
           Photo(electro)catalysis (Adv. Funct. Mater. 46/2017)
    • Authors: Lin Jing; Ruixue Zhu, David Lee Phillips, Jimmy C. Yu
      Abstract: In article number 1703484 Jimmy C. Yu and co-workers report how adding red P nanoparticles onto g-C3N4 effectively suppresses charge trapping and thus prolongs the lifetime of active charges in the photocatalyst. The optimized red P/g-C3N4 composite exhibits a very high photocatalytic hydrogen evolution rate of 2565 μmol h−1 g−1. The charge trapping/de-trapping processes are thoroughly investigated by time-resolved transient absorption spectroscopy.
      PubDate: 2017-12-06T14:15:06.466196-05:
      DOI: 10.1002/adfm.201770277
       
  • Masthead: (Adv. Funct. Mater. 46/2017)
    • PubDate: 2017-12-06T14:15:06.035986-05:
      DOI: 10.1002/adfm.201770274
       
  • Thin Films: Sub-Micrometer Structure Formation during Spin Coating
           Revealed by Time-Resolved In Situ Laser and X-Ray Scattering (Adv. Funct.
           Mater. 46/2017)
    • Authors: Jacobus J. van Franeker; Daniel Hermida-Merino, Cedric Gommes, Kirill Arapov, Jasper J. Michels, René A. J. Janssen, Giuseppe Portale
      Abstract: The droplet-like morphology, typical for many polymer-small-organic-molecule blends processed by spin coating, is quantitatively analyzed by gracing incidence small angle X-ray scattering by Giuseppe Portale and co-workers in article number 1702516. Using a combination of simultaneous X-ray scattering, laser scattering, and laser interferometry measurements, a formation mechanism based on liquid-liquid demixing followed by solvent partitioning is observed during spin coating.
      PubDate: 2017-12-06T14:15:01.474268-05:
      DOI: 10.1002/adfm.201770276
       
  • Organs-on-a-Chip: InVADE: Integrated Vasculature for Assessing Dynamic
           Events (Adv. Funct. Mater. 46/2017)
    • Authors: Benjamin Fook Lun Lai; Locke Davenport Huyer, Rick Xing Ze Lu, Stasja Drecun, Milica Radisic, Boyang Zhang
      Abstract: In article 1703524, Milica Radisic, Boyang Zhang, and co-workers present a user-friendly 96-well plate platform (InVADE, Integrated Vasculature for Assessing Dynamic Events) that utilizes a single vascularized scaffold to replicate in vivo like drug transfer and cell trafficking between multiple organs. Offering highly reproducible in vivo simulation of complex multi-organ biological events, this platform is promising for drug evaluation.
      PubDate: 2017-12-06T14:15:01.075114-05:
      DOI: 10.1002/adfm.201770278
       
  • Contents: (Adv. Funct. Mater. 46/2017)
    • PubDate: 2017-12-06T14:15:00.921476-05:
      DOI: 10.1002/adfm.201770275
       
  • Theranostics: Theranostic Prodrug Vesicles for Reactive Oxygen
           Species-Triggered Ultrafast Drug Release and Local-Regional Therapy of
           Metastatic Triple-Negative Breast Cancer (Adv. Funct. Mater. 46/2017)
    • Authors: Fangyuan Zhou; Bing Feng, Tingting Wang, Dangge Wang, Zhirui Cui, Siling Wang, Chunyong Ding, Zhiwen Zhang, Jian Liu, Haijun Yu, Yaping Li
      Abstract: In article 1703674, Siling Wang, Haijun Yu, Yaping Li, and co-workers report a caged doxorubicin prodrug vesicle (RADV) for imaging-guided cancer therapy. Near-infrared light illumination generates reactive oxygen species that trigger prodrug activation and ultrafast drug release exactly at the tumor site, thus improving therapeutic efficacy while avoiding the side effects of chemotherapeutics. RADV might provide a novel theranostic nanoplatform for local-regional management of cancer.
      PubDate: 2017-12-06T14:15:00.113973-05:
      DOI: 10.1002/adfm.201770272
       
  • Easily Processable and Programmable Responsive Semi-Interpenetrating
           Liquid Crystalline Polymer Network Coatings with Changing Reflectivities
           and Surface Topographies
    • Authors: Augustinus J. J. Kragt; Dirk J. Broer, Albertus P. H. J. Schenning
      Abstract: The fabrication of stimulus-responsive coatings that change both reflectivity and topography is hampered by the lack of easy processable, patternable, and programmable elastomers. Here, an easily applied reflective coating based on a semi-interpenetrating polymer network composed of a liquid crystal elastomer and a liquid crystal network (>15 wt%) is reported. The reflective wavelength of these polysiloxane elastomer photonic coatings can be readily programed by the concentration of chiral reactive mesogen dopant that forms the network. The coatings show a fast and reversible decrease in reflection band intensity with increasing temperature, which can be tuned by the polymer network density. In addition, hierarchical surface relief structures are prepared, which can be reversibly changed with temperature.Responsive coatings based on liquid crystalline polysiloxane and reactive mesogens that change their reflectivity and topography are prepared. The semi-interpenetrating network coating is fabricated by a very simple coating technique. The polymer coatings respond quickly to temperature changes by altering color and surface topographies and these properties can be easily programed by changing the ratio between the polysiloxane and the reactive mesogens.
      PubDate: 2017-12-05T05:26:20.762953-05:
      DOI: 10.1002/adfm.201704756
       
  • Single-Component-Based White Light Photoluminescence Emission via
           Selective Photooxidation in an Organic–Polymer Hybrid System
    • Authors: Minkyung Lee; Intek Song, Misun Hong, Jin Young Koo, Hee Cheul Choi
      Abstract: White light-emitting phenothiazine-poly(dimethylsiloxane) (PTZ–PDMS) composites are formed by a photooxidation reaction. The oxidized PTZ species, i.e., PTZ cation radicals and dication species, are created by electron transfer from the PTZ molecules to PDMS under UV irradiation. In situ UV–vis and electron spin resonance (ESR) spectroscopies are carried out after UV exposure of PTZ–PDMS, and the results provide evidence for the spontaneous ionization of PTZ. The spectral changes indicate the formation of PTZ•+ (radical cation) and PTZ2+ (dication) within the PDMS matrix. Moreover, a combination of PTZ, PTZ•+, and PTZ2+, together with the PDMS matrix, show an unexpected emission of white light with Commission Internationale de L'Eclairage coordinates of 0.34 and 0.32, which are close to those of pure white light. These findings potentially offer a new route and strategy for the development of flexible white light-emitting materials.Single-component white light emitters! White light-emitting phenothiazine–poly(dimethylsiloxane) (PTZ–PDMS) composites are prepared by photooxidation in air. Only the PTZ–PDMS composites prepared by photooxidation in air emit white photoluminescent light under UV irradiation, and the oxidized PTZ show high stability within the PDMS matrix.
      PubDate: 2017-12-04T07:35:47.789354-05:
      DOI: 10.1002/adfm.201703509
       
  • Modular Design of Advanced Catalytic Materials Using Hybrid
           Organic–Inorganic Raspberry Particles
    • Authors: Elijah Shirman; Tanya Shirman, Anna V. Shneidman, Alison Grinthal, Katherine R. Phillips, Hayley Whelan, Eli Bulger, Marcus Abramovitch, Jatin Patil, Rochelle Nevarez, Joanna Aizenberg
      Abstract: Catalysis is one of the most sophisticated areas of materials research that encompasses a diverse set of materials and phenomena occurring on multiple length and time scales. Designing catalysts that can be broadly applied toward global energy and environmental challenges requires the development of universal frameworks for complex catalytic systems through rational and independent (or quasi-independent) optimization of multiple structural and compositional features. Toward addressing this goal, a modular platform is presented in which sacrificial organic colloids bearing catalytic nanoparticles on their surfaces self-assemble with matrix precursors, simultaneously structuring the resulting porous networks and fine-tuning the locations of catalyst particles. This strategy allows combinatorial variations of the material building blocks and their organization, in turn providing numerous degrees of freedom for optimizing the material's functional properties, from the nanoscale to the macroscale. The platform enables systematic studies and rational design of efficient and robust systems for a wide range of catalytic and photocatalytic reactions, as well as their integration into industrial and other real-life environments.The development of efficient and scalable catalytic materials requires consideration of a complex interplay of a variety of chemical and physical processes. This review presents a modular approach for the rational design of advanced catalysts based on self-assembling hybrid colloids, featuring control over parameters on multiple lengthscales.
      PubDate: 2017-12-04T07:31:57.114683-05:
      DOI: 10.1002/adfm.201704559
       
  • The Neuroinflammatory Response to Nanopatterning Parallel Grooves into the
           Surface Structure of Intracortical Microelectrodes
    • Authors: Evon S. Ereifej; Cara S. Smith, Seth M. Meade, Keying Chen, He Feng, Jeffrey R. Capadona
      Abstract: The smooth surface structure of intracortical microelectrodes implanted within the nanometer-scale architecture of brain tissue may contribute to the foreign body response. Here, the neuroinflammatory response to nanopatterning surface grooves etched directly on nonfunctional Michigan-style microelectrodes is explored. Rats implanted with nanopatterned silicon microelectrodes are compared to smooth control implants to observe the effects the grooves have on neuroinflammation. Histology and real-time PCR at 2 and 4 weeks postimplantation quantify glial cell reactivity and activation, inflammation, oxidative stress, and neuronal survival. Histological observations of glial cells and blood–brain barrier permeability do not show appreciable differences between the nanopatterned and control implants. However, silicon microelectrodes with nanopatterned grooves have more high mobility group box 1 (HMGB1) gene expression at 2 weeks and less nitric oxide synthase (NOS2) gene expression at 4 weeks compared to control surfaces. Control samples have increased NOS2, HMGB1, and tumor necrosis factor gene expression from 2 to 4 weeks, while nanopatterned implants have significant decrease in CD14 gene expression from 2 to 4 weeks. Collectively the results indicate that etching nanopatterned grooves do not reduce histological markers of neuroinflammation compared to control implants, but gene expression results encourage further investigation.The neuroinflammatory response to biomimetic nanogrooves etched directly on the surface of nonfunctional Michigan style microelectrodes is explored. Rats implanted with nanopatterned microelectrodes are compared to smooth control implants to observe the effects the nanogrooves have on neuroinflammation. Results indicate that etching nanogrooves do not reduce histological markers of neuroinflammation compared to control implants, but gene expression results encourage further investigation.
      PubDate: 2017-12-04T07:31:06.128447-05:
      DOI: 10.1002/adfm.201704420
       
  • Hollow Mesoporous Carbon Nanocubes: Rigid-Interface-Induced Outward
           Contraction of Metal-Organic Frameworks
    • Authors: Chao Liu; Xiaodan Huang, Jing Wang, Hao Song, Yannan Yang, Yang Liu, Jiansheng Li, Lianjun Wang, Chengzhong Yu
      Abstract: Novel carbon materials derived from metal-organic frameworks (MOFs) have attracted much attention, but the commonly inevitable inward contraction during the carbonization process has restricted their structural variety and applications. In this work, a novel rigid-interface induced outward contraction approach is reported for synthesizing hollow mesoporous carbon nanocubes (HMCNCs) by using ZIF-8 nanocubes as precursors. HMCNCs exhibit a cubic morphology with the particle sizes slightly larger than ZIF-8 nanocubes. Due to the unique outward contraction process, uniform carbon nanocubes with a hollow cavity, an outer microporous shell, and an inner mesoporous wall are simultaneously formed with a large pore size (25 nm), high surface area (1085.7 m2 g−1), high porosity (3.77 cm3 g−1), and high nitrogen content (12.2%). When used as a cathode material for Li–SeS2 batteries, the HMCNCs deliver a stable capacity of 812.6 mA h g−1 at 0.2 A g−1 after 100 cycles and an outstanding rate capability (455.1 mA h g−1 at 5.0 A g−1). The findings may pave the way for the construction of distinctive MOF-derived carbon materials for various applications.Metal-organic framework (MOF)-derived hollow mesoporous carbon nanocubes (HMCNCs) with a uniform nanocubic morphology, a large hollow cavity, an outer microporous shell, and an inner mesoporous shell are synthesized via a novel rigid-interface induced outward contraction approach. When used as a cathode substrate for Li–SeS2 batteries, HMCNCs deliver superior electrochemical performances with stable capacity and outstanding rate capability.
      PubDate: 2017-12-04T07:25:41.247332-05:
      DOI: 10.1002/adfm.201705253
       
  • Hofmeister Effect-Assisted One Step Fabrication of Ductile and Strong
           Gelatin Hydrogels
    • Authors: Qingyan He; Yan Huang, Shaoyun Wang
      Abstract: Hydrogels with high strength and ductility are normally prepared from synthetic polymers, and most protein-based hydrogels are soft and brittle. Here, a strong, ductile gelatin hydrogel is prepared by simply soaking a virgin gelatin gel in an ammonium sulfate solution. The polymer chains in the covalent, crosslink-free network can freely move to homogeneously distribute stress, and more importantly, the highly kosmotropic ammonium sulfate ions greatly enhance the hydrophobic interactions and chain bundling within the gelatin gels. As a result, the treated hydrogels have an extraordinary ultimate strength (compressive and tensile strains of over 99% and 500%, respectively, and stresses of 12 and 3 MPa) superior to that of common protein gels. The physical crosslinks introduced by the Hofmeister effect can rapidly absorb energy and sustain large deformations via decrosslinking and dissociation, which result in energy dissipation and antifatigue properties. The effects of the gelatin and (NH4)2SO4 concentrations on the hydrogel mechanics are evaluated, and the possible strengthening mechanism is discussed. The effect of various ions in the Hofmeister series on the gelatin hydrogel is also investigated. Kosmotropic ions enhance the mechanical properties, whereas chaotropic ions soften and dissolve the gel.A gelatin-based, strong, ductile hydrogel is prepared by soaking a virgin gelatin hydrogel in ammonium sulfate solutions. Chain bundling, hydrophobic interactions, and microphase separation regions induced by the Hofmeister effect endow the hydrogels with superior mechanical properties.
      PubDate: 2017-12-04T05:32:08.197149-05:
      DOI: 10.1002/adfm.201705069
       
  • Ultrafast Nanoscale Polymer Coating on Porous 3D Structures Using
           Microwave Irradiation
    • Authors: Woongchul Choi; Kyungwho Choi, Choongho Yu
      Abstract: Thin polymer coatings are very popular, but the coatings on uneven surfaces or porous 3D structures are difficult to obtain with traditional methods. The pores are easily clogged due to nonuniform polymer curing processes caused by inevitable macroscale temperature gradients from their hotter outer to colder inner sides. Here an ultrafast and simple fabrication method is developed to obtain nanoscale coating layers on the inner and outer surfaces of a porous 3D sponge-like carbon nanotube (CNT). Microwave irradiation rapidly and selectively heats the CNT immersed in a mixture solution of an uncured polymer and a diluent solvent, solidifying the polymer only adjacent to the CNT with five repeated 3 s microwave irradiation. The coating layers can be controlled by adjusting the concentration of the uncured polymer in the solution and controlling the CNT temperature via microwave power and irradiation time. The nanoscale coating strongly ties the junction between CNTs without filling the pores with the polymer, resulting in excellent resilience to compressive stress with large strains (≈180 kPa at 60%), which is maintained throughout repeated 8000 cycles of 0–60% strain. The unfilled pores allow for maintaining the low thermal conductivity, ≈26 mW m−1 K−1, and the electrical resistance is varied with strain. This facile selective polymer curing methodology can be utilized in processing various materials with uneven surfaces or pores.An ultrafast and simple fabrication method is developed to produce uniform nanoscale coating layers even on the inner surfaces of a porous 3D sponge-like carbon nanotube (CNT). Microwave irradiation rapidly and selectively heats the CNT immersed in a mixture solution of an uncured polymer and a diluent solvent, solidifying the polymer only adjacent to the CNT within seconds.
      PubDate: 2017-12-04T05:31:15.699961-05:
      DOI: 10.1002/adfm.201704877
       
  • Functionalized Cubic Mesoporous Silica as a Non-Chemodosimetric
           Fluorescence Probe and Adsorbent for Selective Detection and Removal of
           Bisulfite Anions along with Toxic Metal Ions
    • Authors: Sobhan Chatterjee; Alok Ranjan Paital
      Abstract: Dual signaling and remediation systems for detection and adsorption of toxic analytes have gained more attention over sensory probes only. However, most of the sensors for bisulfites are chemodosimetric probes, which are irreversible and having drawbacks of absolute selectivity, recyclability, and solubility in a pure aqueous system. To address above drawbacks a new non-chemodosimetric probe material with a strong hydrogen bonding pocket for bisulfites is developed. Synthesis of cubic mesoporous silica by a modified Stober process followed by functionalization with 2,2′-(((((3-(triethoxysilyl)propyl)azanediyl)bis(methylene))bis(2,1-phenylene))bis(oxy))bis(N-(4-((E)-phenyldiazenyl)phenyl)acetamide) (AZOL) has given a fluorogenic silica probe material SiO2@AZOL. This material shows selectivity toward bisulfite anion (limit of detection (LOD): 64 ppb) and Hg2+, Cd2+, Cu2+, and Zn2+ cations (LOD: 126, 95, 14, and 27 ppb, respectively) among various analytes. The adsorption studies for these toxic analytes (HSO3−, Hg2+, Cd2+, Cu2+, and Zn2+) show an extraction efficiency of around 99% and adsorption capacities of 873, 630, 633, 260, and 412 mg g−1, respectively. Spectroscopic studies along with adsorption, striping, and regeneration studies reveal that this material is a recyclable sensory cum adsorbent material for these toxic analytes. Moreover, this material can be used as a sensitive probe material for determination of HSO3− levels in various sugar samples.This work describes a new functional material based non-chemodosimetric probe for selective detection and removal of bisulfite among various anions through hydrogen bonding and coordination driven selectivity toward several toxic metal ions (Hg2+, Cd2+, Cu2+, and Zn2+) in an aqueous system with very high adsorption capacity. Apart from dual functions, it displays excellent recycling stability for a true detection and remediation system.
      PubDate: 2017-12-04T05:25:03.599755-05:
      DOI: 10.1002/adfm.201704726
       
  • Potassium-Ion Battery Anode Materials Operating through the
           Alloying–Dealloying Reaction Mechanism
    • Authors: Irin Sultana; Md Mokhlesur Rahman, Ying Chen, Alexey M. Glushenkov
      Abstract: Anode materials that operate via the alloying–dealloying reaction mechanism are well known in established and maturing battery systems such as lithium-ion and sodium-ion batteries. Recently, a new type of metal-ion battery that utilizes K+ ions in its operating principle has attracted significant attention due to a possibility of building high voltage cells using an abundant potassium ionic shuttle. Establishing promising electrode materials is of paramount importance for this new type of battery. This feature article summarizes available early results on the alloying–dealloying anode materials in potassium electrochemical cells. Based on original research (some data are presented for the first time) and independently published literature, experimental results on silicon, tin, phosphorus, antimony, and lead-containing anodes are critically discussed. The electrochemical properties, charge storage mechanisms, and achievable capacities are considered. The results are compared with the behaviors of the same materials in lithium and sodium cells, and the importance of the volumetric parameters of electrodes is emphasized. Finally, a number of further research directions in these interesting anode materials are suggested. The feature article provides a useful reference for the growing number of researchers and specialists working in the field of emerging metal-ion batteries with non-lithium chemistries.Anode materials are the key components of a new type of rechargeable metal-ion batteries based on potassium. A class of high capacity anode materials that operate through the mechanism of electrochemical alloying with potassium is discussed. Electrode systems incorporating Sn, P, and Sb are given particular attention; the current state of the field and future research directions are considered.
      PubDate: 2017-12-04T05:24:00.82958-05:0
      DOI: 10.1002/adfm.201703857
       
  • Contrasting Effects of Energy Transfer in Determining Efficiency
           Improvements in Ternary Polymer Solar Cells
    • Authors: Wei Li; Yu Yan, Yanyan Gong, Jinlong Cai, Feilong Cai, Robert S. Gurney, Dan Liu, Andrew J. Pearson, David G. Lidzey, Tao Wang
      Abstract: Crystallizable, high-mobility conjugated polymers have been employed as secondary donor materials in ternary polymer solar cells in order to improve device efficiency by broadening their spectral response range and enhancing charge dissociation and transport. Here, contrasting effects of two crystallizable polymers, namely, PffBT4T-2OD and PDPP2TBT, in determining the efficiency improvements in PTB7-Th:PC71BM host blends are demonstrated. A notable power conversion efficiency of 11% can be obtained by introducing 10% PffBT4T-2OD (relative to PTB7-Th), while the efficiency of PDPP2TBT-incorporated ternary devices decreases dramatically despite an enhancement in hole mobility and light absorption. Blend morphology studies suggest that both PffBT4T-2OD and PDPP2TBT are well dissolved within the host PTB7-Th phase and facilitate an increased degree of phase separation between polymer and fullerene domains. While negligible charge transfer is determined in binary blends of each polymer mixture, effective energy transfer is identified from PffBT4T-2OD to PTB7-Th that contributes to an improvement in ternary blend device efficiency. In contrast, energy transfer from PTB7-Th to PDPP2TBT worsens the efficiency of the ternary device due to inefficient charge dissociation between PDPP2TBT and PC71BM.Contrasting effects in determining device efficiencies are observed when incorporating two crystallizable, high-mobility conjugated polymers, namely, PffBT4T-2OD and PDPP2TBT, as the secondary donor materials to PTB7-Th:PC71BM-based solar cells, due to different energy transfer between the electron-donating polymers in the ternary photovoltaic blends.
      PubDate: 2017-12-04T05:22:23.513506-05:
      DOI: 10.1002/adfm.201704212
       
  • Exosome as a Vehicle for Delivery of Membrane Protein Therapeutics, PH20,
           for Enhanced Tumor Penetration and Antitumor Efficacy
    • Authors: Yeonsun Hong; Gi-Hoon Nam, Eunee Koh, Sangmin Jeon, Gi Beom Kim, Cherlhyun Jeong, Dong-Hwee Kim, Yoosoo Yang, In-San Kim
      Abstract: As biochemical and functional studies of membrane protein remain a challenge, there is growing interest in the application of nanotechnology to solve the difficulties of developing membrane protein therapeutics. Exosome, composed of lipid bilayer enclosed nanosized extracellular vesicles, is a successful platform for providing a native membrane composition. This study reports an enzymatic exosome, which harbors native PH20 hyaluronidase (Exo-PH20), which is able to penetrate deeply into tumor foci via hyaluronan degradation, allowing tumor growth inhibition and increased T cell infiltration into the tumor. This exosome-based strategy is developed to overcome the immunosuppressive and anticancer therapy-resistant tumor microenvironment, which is characterized by an overly accumulated extracellular matrix. Notably, this engineered exosome with the native glycosylphosphatidylinositol-anchored form of hyaluronidase has a higher enzymatic activity than a truncated form of the recombinant protein. In addition, the exosome-mediated codelivery of PH20 hyaluronidase and a chemotherapeutic (doxorubicin) efficiently inhibits tumor growth. This exosome is designed to degrade hyaluronan, thereby augmenting nanoparticle penetration and drug diffusion. The results thus show that this is a promising exosome-based platform that harbors not only a membrane-associated enzyme with high activity but also therapeutic payloads.A novel exosome-based membrane protein therapeutic harboring native PH20 hyaluronidase (Exo-PH20) is successfully developed. The GPI-anchored PH20, presented in the lipid raft domains of the exosomes, has a higher enzymatic activity than the truncated form of recombinant protein. This enzymatic exosome is able to penetrate deeply into tumor foci via hyaluronan degradation, allowing tumor growth inhibition and increased T cell infiltration into the tumor.
      PubDate: 2017-12-04T05:21:42.165983-05:
      DOI: 10.1002/adfm.201703074
       
  • From Fragility to Flexibility: Construction of Hydrogel Bridges toward a
           Flexible Multifunctional Free-Standing CaCO3 Film
    • Authors: Xue Yuan; Wu-Cheng Nie, Chen Xu, Xiao-Hui Wang, Qian Xiao, Fei Song, Xiu-Li Wang, Yu-Zhong Wang
      Abstract: Free-standing CaCO3 materials are an important member in biological systems because of their existence in many natural organisms such as nacre, shell, and crustacean cuticle. However, toughness of those artificial mineral films is sacrificed once their inorganic content is up to 90%, thus free-standing characteristics have seldom been achieved for CaCO3 films, let alone their real applications. Herein a fast and simple method for constructing hydrogel “bridges” for CaCO3 microparticles is presented, developing highly flexible free-standing CaCO3 films with only 5% organic content. Such integrated films have underwater superoleophobicity and self-cleaning function, which guarantee their repeated application in oil/water separation. Furthermore, heavy metal ions can be efficiently removed by simple filtration with the films. Because of the self-similar structure, the films are able to resist mechanical abrasion without losing the anti-wetting property and separation efficiency. The free-standing CaCO3 films are put forward for the first time to practical application, demonstrating the strategy can bring a brilliant prospect to artificial biomineral materials.A highly flexible free-standing CaCO3 film with multiple functions is fabricated by constructing spider web-simulated hydrogel bridges to connect fragile CaCO3 microparticles together. Owing to underwater superoleophobicity and their self-cleaning function, allow to apply such films for the first time in oil/water separation and heavy metal removal. A self-similar structure of the film guarantees good mechanical abrasion resistance without losing functions.
      PubDate: 2017-12-04T05:16:50.590929-05:
      DOI: 10.1002/adfm.201704956
       
  • Oxygen Clusters Distributed in Graphene with “Paddy Land” Structure:
           Ultrahigh Capacitance and Rate Performance for Supercapacitors
    • Authors: Zheng Liu; Lili Jiang, Lizhi Sheng, Qihang Zhou, Tong Wei, Bingsen Zhang, Zhuangjun Fan
      Abstract: The introduction of surface functional groups onto graphene can provide additional pseudocapacitance for supercapacitors. However, the compensation for the loss of electrical conductivity arising from the disruption of the conjugated system remains a big challenge. Here, a novel strategy is reported for the design of oxygen clusters distributed in graphene with “paddy land” structure via a low-temperature annealing process. Moreover, the distribution, content, and variety of oxygen groups and the conductivity of reduced graphene oxide (RGO) can be easily adjusted by annealing temperature and time. First-principles calculations demonstrate that “paddy land” structure exhibits conjugated carbon network, ultralow HOMO–LUMO gap, and long span of atomic charge values, which are beneficial for the enhanced pseudocapacitance and rate performance. As a result, the functionalized graphene (GO-160-8D) exhibits high specific capacitance of 436 F g−1 at 0.5 A g−1, exceeding the values of previously reported RGO materials, as well as excellent rate performance (261 F g−1 at 50 A g−1) and cycling stability (94% of capacitance retention after 10 000 cycles). The findings may open a door for finely controlling the location and density of functionalities on graphene for applications in energy storage and conversion fields via a green and energy-efficient process.A novel strategy for low-temperature balance of oxygen content and conductivity of reduced graphene oxide (RGO) with “paddy land” structure is reported. As a result, the functionalized graphene exhibits high specific capacitance of 436 F g−1 at 0.5 A g−1, as well as excellent rate performance (261 F g−1 at 50 A g−1) and cycling stability (94% of capacitance retention after 10 000 cycles).
      PubDate: 2017-12-04T05:16:23.454443-05:
      DOI: 10.1002/adfm.201705258
       
  • Stimuli-Responsive Nucleic Acid-Based Polyacrylamide Hydrogel-Coated
           Metal–Organic Framework Nanoparticles for Controlled Drug Release
    • Authors: Wei-Hai Chen; Wei-Ching Liao, Yang Sung Sohn, Michael Fadeev, Alessandro Cecconello, Rachel Nechushtai, Itamar Willner
      Abstract: The synthesis of doxorubicin-loaded metal–organic framework nanoparticles (NMOFs) coated with a stimuli-responsive nucleic acid-based polyacrylamide hydrogel is described. The formation of the hydrogel is stimulated by the crosslinking of two polyacrylamide chains, PA and PB, that are functionalized with two nucleic acid hairpins (4) and (5) using the strand-induced hybridization chain reaction. The resulting duplex-bridged polyacrylamide hydrogel includes the anti-ATP (adenosine triphosphate) aptamer sequence in a caged configuration. The drug encapsulated in the NMOFs is locked by the hydrogel coating. In the presence of ATP that is overexpressed in cancer cells, the hydrogel coating is degraded via the formation of the ATP–aptamer complex, resulting in the release of doxorubicin drug. In addition to the introduction of a general means to synthesize drug-loaded stimuli-responsive nucleic acid-based polyacrylamide hydrogel-coated NMOFs hybrids, the functionalized NMOFs resolve significant limitations associated with the recently reported nucleic acid-gated drug-loaded NMOFs. The study reveals substantially higher loading of the drug in the hydrogel-coated NMOFs as compared to the nucleic acid-gated NMOFs and overcomes the nonspecific leakage of the drug observed with the nucleic-acid-protected NMOFs. The doxorubicin-loaded, ATP-responsive, hydrogel-coated NMOFs reveal selective and effective cytotoxicity toward MDA-MB-231 breast cancer cells, as compared to normal MCF-10A epithelial breast cells.A stimuli-responsive nucleic acid-based hydrogel coating drug-loaded metal–organic framework nanoparticles (NMOF) acts as an effective carrier for controlled drug release. This is exemplified with ATP (adenosine triphosphate)-responsive hydrogel-coated NMOFs loaded with doxorubicin. In the presence of ATP, overexpressed in cancer cells, the hydrogel coating is dissociated, resulting in the release of the drug. The hybrid NMOFs reveal selective cytotoxicity toward MDA-MB-231 breast cancer cells.
      PubDate: 2017-12-04T02:26:16.40096-05:0
      DOI: 10.1002/adfm.201705137
       
  • 2D Dual-Metal Zeolitic-Imidazolate-Framework-(ZIF)-Derived Bifunctional
           Air Electrodes with Ultrahigh Electrochemical Properties for Rechargeable
           Zinc–Air Batteries
    • Authors: Tingting Wang; Zongkui Kou, Shichun Mu, Jingping Liu, Daping He, Ibrahim Saana Amiinu, Wen Meng, Kui Zhou, Zhixiong Luo, Somboon Chaemchuen, Francis Verpoort
      Abstract: Here first a 2D dual-metal (Co/Zn) and leaf-like zeolitic imidazolate framework (ZIF-L)-pyrolysis approach is reported for the low-cost and facile preparation of Co nanoparticles encapsulated into nitrogen-doped carbon nanotubes (Co-N-CNTs). Importantly, the reasonable Co/Zn molar ratio in the ZIF-L is the key to the emergence of the encapsulated microstructure. Specifically, high-dispersed cobalt nanoparticles are fully encapsulated in the tips of N-CNTs, leading to the full formation of highly active Co–N–C moieties for oxygen reduction and evolution reactions (ORR and OER). As a result, the obtained Co-N-CNTs present superior electrocatalytic activity and stability toward ORR and OER over the commercial Pt/C and IrO2 as well as most reported metal-organic-framework-derived catalysts, respectively. Remarkably, as bifunctional air electrodes of the Zn–air battery, it also shows extraordinary charge–discharge performance. The present concept will provide a guideline for screening novel 2D metal-organic frameworks as precursors to synthesize advanced multifunctional nanomaterials for cross-cutting applications.2D dual-metal zeolitic imidazolate framework with leaf-like microstructure is rationally chosen as material platform for the facile fabrication of high-dispersed cobalt nanoparticles encapsulated into nitrogen-doped carbon nanotubes as bifunctional air electrodes for a high-performance rechargeable zinc–air battery.
      PubDate: 2017-12-04T02:21:33.8366-05:00
      DOI: 10.1002/adfm.201705048
       
  • Optical Chemical Barcoding Based on Polarization Controlled Plasmonic
           Nanopixels
    • Authors: Daniel Peter Langley; Eugeniu Balaur, Yongsop Hwang, Catherine Sadatnajafi, Brian Abbey
      Abstract: Plasmonic devices offer the possibility of passively detecting changes in local chemistry that opens up a wide range of applications from molecular sensing to monitoring water quality. Conventional plasmonics have previously shown great promise as nanoscale chemical sensors through detection of small variations in the local refractive index (RI). The motivation behind using plasmonics for these applications includes the fact that detection is entirely passive and the devices themselves can be readily miniaturized. Previously, a lack of any control over the output of these devices, has fundamentally limited their application to chemicals which produce clearly identifiable resonances within the range of detection. Here it is demonstrated that microfluidic devices, incorporating polarization-controlled plasmonic nanopixels, allow the device response to be tuned to the particular analyte of interest, anywhere within the visible spectrum. This dramatically increases the effective dynamic range and allows local variations in RI to be perceived directly as color changes by the human eye. Active control over the output of the device also enables clear differentiation between a number of different analytes, paving the way for plasmonics to be used for a wide range of real-world chemical sensing applications.Plasmonic devices using an asymmetric array of nanoscale crosses enable the passive detection of changes in local chemistry that opens up a wide range of applications from molecular sensing to monitoring water quality. Microfluidic devices, incorporating polarization-controlled plasmonic nanopixels, allow the device response to be tuned to the particular analyte of interest anywhere within the visible spectrum.
      PubDate: 2017-12-04T02:21:04.175012-05:
      DOI: 10.1002/adfm.201704842
       
  • Biomimetic Chitin–Silk Hybrids: An Optically Transparent Structural
           Platform for Wearable Devices and Advanced Electronics
    • Authors: Moo-Seok Hong; Gwang-Mun Choi, Joohee Kim, Jiuk Jang, Byeongwook Choi, Joong-Kwon Kim, Seunghwan Jeong, Seongmin Leem, Hee-Young Kwon, Hyun-Bin Hwang, Hyeon-Gyun Im, Jang-Ung Park, Byeong-Soo Bae, Jungho Jin
      Abstract: The cuticles of insects and marine crustaceans are fascinating models for man-made advanced functional composites. The excellent mechanical properties of these biological structures rest on the exquisite self-assembly of natural ingredients, such as biominerals, polysaccharides, and proteins. Among them, the two commonly found building blocks in the model biocomposites are chitin nanofibers and silk-like proteins with β-sheet structure. Despite being wholly organic, the chitinous protein complex plays a key role for the biocomposites by contributing to the overall mechanical robustness and structural integrity. Moreover, the chitinous protein complex alone without biominerals is optically transparent (e.g., dragonfly wings), thereby making it a brilliant model material system for engineering applications where optical transparency is essentially required. Here, inspired by the chitinous protein complex of arthropods cuticles, an optically transparent biomimetic composite that hybridizes chitin nanofibers and silk fibroin (β-sheet) is introduced, and its potential as a biocompatible structural platform for emerging wearable devices (e.g., smart contact lenses) and advanced displays (e.g., transparent plastic cover window) is demonstrated.An optically transparent biomimetic hybrid material consisting of chitin nanofibers and silk fibroin is reported and its use as a biocompatible structural platform for emerging wearable devices (e.g., smart contact lenses) and advanced electronics (e.g., display cover window) is demonstrated.
      PubDate: 2017-12-04T02:16:27.342484-05:
      DOI: 10.1002/adfm.201705480
       
  • Preconcentration of Nitroalkanes with Archetype Metal–Organic Frameworks
           (MOFs) as Concept for a Sensitive Sensing of Explosives in the Gas Phase
    • Authors: Max Rieger; Michael Wittek, Philip Scherer, Stefan Löbbecke, Klaus Müller-Buschbaum
      Abstract: Thermal desorption based enrichment is a general concept that can enhance any detection system's sensitivity and selectivity. Given their large interior surface area and chemical versatility, archetype metal–organic frameworks (MOFs) are selected for preconcentration of explosives and their precursors occurring in low concentrations, and are compared to the state-of-the-art sorbent Tenax TA. Applying inverse gas chromatography (iGC), this study shows that several archetype MOFs, namely HKUST-1 and MIL-53, surpass Tenax regarding their specific retention volume for nitromethane, a typical ingredient in improvised explosives. Using linear hydrocarbons as reference probe molecules, the dispersive surface energy is determined for all MOFs along with the specific contribution of the nitro group for HKUST-1 and ZIF-8. Trends from pulse-chromatographic iGC-investigations are mostly followed in breakthrough and thermal desorption experiments using a 1000 ppm nitromethane source. In these experiments, HKUST-1 proves the peak substance, with enrichment factors being 109-fold higher than for Tenax, followed by MIL-53. In case of HKUST-1, this factor is successfully reproduced for a 1 ppm concentration scenario. This shows that archetype MOFs can be suitable or even superior candidates for a sensitive sensing of nitroalkane explosives from the gas phase by a concept of preconcentration.Archetype metal–organic frameworks (MOFs) are evaluated for preconcentrator enhanced sensor-systems using inverse gas chromatography. Thereby, the overall sensitivity of detection systems by thermal enrichment is strongly increased. Enrichment factors for nitromethane at 1 ppm as relevant substance in home-made explosives are determined to be about 100× higher for the MOF HKUST-1 than for state-of-the-art material Tenax TA.
      PubDate: 2017-12-01T07:15:48.432139-05:
      DOI: 10.1002/adfm.201704250
       
  • A High-k Fluorinated P(VDF-TrFE)-g-PMMA Gate Dielectric for
           High-Performance Flexible Field-Effect Transistors
    • Authors: Eul-Yong Shin; Hye Jin Cho, Sungwoo Jung, Changduk Yang, Yong-Young Noh
      Abstract: A newly synthesized high-k polymeric insulator for use as gate dielectric layer for organic field-effect transistors (OFETs) obtained by grafting poly(methyl methacrylate) (PMMA) in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) via atom transfer radical polymerization transfer is reported. This material design concept intents to tune the electrical properties of the gate insulating layer (capacitance, leakage current, breakdown voltage, and operational stability) of the high-k fluorinated polymer dielectric without a large increase in operating voltage by incorporating an amorphous PMMA as an insulator. By controlling the grafted PMMA percentage, an optimized P(VDF-TrFE)-g-PMMA with 7 mol% grafted PMMA showing reasonably high capacitance (23–30 nF cm−2) with low voltage operation and negligible current hysteresis is achieved. High-performance low-voltage-operated top-gate/bottom-contact OFETs with widely used high mobility polymer semiconductors, poly[[2,5-bis(2-octyldodecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo [3,4-c]pyrrole-1,4-diyl]-alt-[[2,2′-(2,5-thiophene)bis-thieno(3,2-b)thiophene]-5,5′-diyl]] (DPPT-TT), and poly([N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)) are demonstrated here. DPPT-TT OFETs with P(VDF-TrFE)-g-PMMA gate dielectrics exhibit a reasonably high field-effect mobility of over 1 cm2 V−1 s−1 with excellent operational stability.A high-k polymeric insulator is developed by chemically grafting poly(methylmethacrylate) (PMMA) to poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) for use as a gate dielectric layer in organic field-effect transistors (OFETs). A device with an optimized P(VDF-TrFE)-g-PMMA ratio (7% grafted ratio) shows a high capacitance of 23-30 nF cm−2. Poly[[2,5-bis(2-octyldodecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl]-alt-[[2,2′-(2,5-thiophene)bis-thieno(3,2-b)thiophene]-5,5′-diyl]] (DPPT-TT) OFETs with P(VDF-TrFE)-g-PMMA exhibit high field-effect mobility of over 1 cm2 V−1 s−1.
      PubDate: 2017-12-01T03:18:41.661319-05:
      DOI: 10.1002/adfm.201704780
       
  • Synaptic Suppression Triplet-STDP Learning Rule Realized in Second-Order
           Memristors
    • Authors: Rui Yang; He-Ming Huang, Qing-Hui Hong, Xue-Bing Yin, Zheng-Hua Tan, Tuo Shi, Ya-Xiong Zhou, Xiang-Shui Miao, Xiao-Ping Wang, Shao-Bo Mi, Chun-Lin Jia, Xin Guo
      Abstract: The synaptic weight modification depends not only on interval of the pre-/postspike pairs according to spike-timing dependent plasticity (classical pair-STDP), but also on the timing of the preceding spike (triplet-STDP). Triplet-STDP reflects the unavoidable interaction of spike pairs in natural spike trains through the short-term suppression effect of preceding spikes. Second-order memristors with one state variable possessing short-term dynamics work in a way similar to the biological system. In this work, the suppression triplet-STDP learning rule is faithfully demonstrated by experiments and simulations using second-order memristors. Furthermore, a leaky-integrate-and-fire (LIF) neuron is simulated using a circuit constructed with second-order memristors. Taking the advantage of the LIF neuron, various neuromimetic dynamic processes, including local graded potential leaking out, postsynaptic impulse generation and backpropagation, and synaptic weight modification according to the suppression triplet-STDP rule, are realized. The realized weight-dependent pair- and triplet-STDP rules are clearly in line with findings in biology. The physically realized triplet-STDP rule is powerful in developing direction and speed selectivity for complex pattern recognition and tracking tasks. These scalable artificial synapses and neurons realized in second-order memristors can intrinsically capture the neuromimetic dynamic processes; they are the promising building blocks for constructing brain-inspired computation systems.Compared with the classical pair-spike-timing dependent plasticity (STDP), the triplet-STDP is an advanced synaptic plasticity that induces improved learning capability. The triplet-STDP is physically demonstrated and a leaky-integrate-and-fire (LIF) neuron is simulated using second-order memristors. The biorealistic implementation of the triplet-STDP and the LIF neuron offers an efficient approach to the artificial intelligence through a simple artificial neural network.
      PubDate: 2017-12-01T03:18:20.368059-05:
      DOI: 10.1002/adfm.201704455
       
  • Electrochemically Inert g-C3N4 Promotes Water Oxidation Catalysis
    • Authors: Yaping Chen; Qian Zhou, Guoqiang Zhao, Zhenwei Yu, Xiaolin Wang, Shi Xue Dou, Wenping Sun
      Abstract: Electrode surface wettability is critically important for heterogeneous electrochemical reactions taking place in aqueous and nonaqueous media. Herein, electrochemically inert g-C3N4 (GCN) is successfully demonstrated to significantly enhance water oxidation by constructing a superhydrophilic catalyst surface and promoting substantial exposure of active sites. As a proof-of-concept application, superhydrophilic GCN/Ni(OH)2 (GCNN) hybrids with monodispersed Ni(OH)2 nanoplates strongly anchored on GCN are synthesized for enhanced water oxidation catalysis. Owing to the superhydrophilicity of functionalized GCN, the surface wettability of GCNN (contact angle 0°) is substantially improved as compared with bare Ni(OH)2 (contact angle 21°). Besides, GCN nanosheets can effectively suppress Ni(OH)2 aggregation to help expose more active sites. Benefiting from the well-defined catalyst surface, the optimal GCNN hybrid shows significantly enhanced electrochemical performance over bare Ni(OH)2 nanosheets, although GCN is electrochemically inert. In addition, similar catalytic performance promotion resulting from wettability improvement induced by incorporation of hydrophilic GCN is also successfully demonstrated on Co(OH)2. The present results demonstrate that, in addition to developing new catalysts, building efficient surface chemistry is also vital to achieve extraordinary water oxidation performance.Wettability matters: electrochemically inert functionalized g-C3N4 can significantly enhance water oxidation catalysis by constructing a superhydrophilic catalyst surface and promoting substantial exposure of active sites. This work opens a new avenue for the development of highly efficient catalysts for electrochemical reactions taking place in aqueous and nonaqueous media.
      PubDate: 2017-12-01T03:16:59.155751-05:
      DOI: 10.1002/adfm.201705583
       
  • Bio-Inspired Photonic Materials: Prototypes and Structural Effect Designs
           for Applications in Solar Energy Manipulation
    • Authors: Han Zhou; Jun Xu, Xianghui Liu, Haiwen Zhang, Dantong Wang, Zhihan Chen, Di Zhang, Tongxiang Fan
      Abstract: Natural creatures have evolved elaborate photonic nanostructures on multiple scales and dimensions in a hierarchical, organized way to realize controllable absorption, reflection, or transmitting the desired wavelength of the solar spectrum. A bio-inspired strategy is a powerful and promising way for solar energy manipulation. This feature article presents the state-of-the-art progress on bio-inspired photonic materials on this particular application. The article first briefly recalls the physical origins of natural photonic effects and catalogues the typical natural photonic prototypes including light harvesting, broadband reflection, selective reflection, and UV/IR response. Next, typical applications are categorized into two primary areas: solar energy utilization and reflection. Recent advances including solar-to-electricity, solar-to-fuels, solar-thermal (e.g., photothermal converters, infrared detectors, thermoelectric materials, smart windows, and solar steam generation) are highlighted in the first part. Meanwhile, solar energy reflection involving infrared stealth, radiative cooling, and micromirrors are also addressed. In particular, this article focuses on bioinspired design principles, structural effects on functions, and future trends. Finally, the main challenges and prospects for the next generation of bioinspired photonic materials are discussed, including new design concepts, emerging ideas, and possible strategies.Bio-inspired photonic design is a powerful and promising way for solar energy manipulation. This feature article presents the state-of-the-art progress on bio-inspired photonic materials. Typical natural photonic prototypes including light harvesting, broadband reflection, selective reflection, and UV/Infrared response are summarized. Solar energy manipulation applications including solar-to-electricity, solar-to-fuels, solar–thermal (photothermal converters, infrared detectors, thermoelectric materials, etc.), and solar energy reflection are highlighted.
      PubDate: 2017-11-30T09:52:25.764119-05:
      DOI: 10.1002/adfm.201705309
       
  • In Situ Exfoliated, N-Doped, and Edge-Rich Ultrathin Layered Double
           Hydroxides Nanosheets for Oxygen Evolution Reaction
    • Authors: Yanyong Wang; Chao Xie, Zhiyuan Zhang, Dongdong Liu, Ru Chen, Shuangyin Wang
      Abstract: The number of catalytically reactive sites and their intrinsic electrocatalytic activity strongly affect the performance of electrocatalysts. Recently, there are growing concerns about layered double hydroxides (LDHs) for oxygen evolution reaction (OER). Exfoliating LDHs is an effective method to increase the reactive sites, however, a traditional liquid phase exfoliation method is usually very labor-intensive and time-consuming. On the other hand, proper heteroelement doping and edge engineering are helpful to tune the intrinsic activity of reactive sites. In this work, bulk CoFe LDHs are successfully exfoliated into ultrathin CoFe LDHs nanosheets by nitrogen plasma. Meanwhile, nitrogen doping and defects are introduced into exfoliated ultrathin CoFe LDHs nanosheets. The number of reactive sites can be increased efficiently by the formation of ultrathin CoFe LDHs nanosheets, the nitrogen dopant alters the surrounding electronic arrangement of reactive site facilitating the adsorption of OER intermediates, and the electrocatalytic activity of reactive sites can be further tuned efficiently by introducing defects which increase the number of dangling bonds neighboring reactive sites and decrease the coordination number of reactive sites. With these advantages, this electrocatalyst shows excellent OER activity with an ultralow overpotential of 233 mV at 10 mA cm−2.Engineering the edge and corner active sites and realizing nitrogen incorporation in ultrathin N-CoFe layered double hydroxides (LDHs) are implemented and synthesized simultaneously using N2 plasma to treat bulk CoFe LDHs nanosheets. With these unique features, the ultrathin N-CoFe LDHs nanosheets as electrocatalyst show excellent oxygen evolution reaction properties.
      PubDate: 2017-11-30T05:38:24.988761-05:
      DOI: 10.1002/adfm.201703363
       
  • Precise Assembly of Synthetic Carriers of siRNA through a Series of
           Interlocked Thermodynamically Self-Regulated Processes
    • Authors: Jia Feng; Shun Chen, Xuemei Ge, Fei Wu, Guang Bai, Tuo Jin
      Abstract: A synthetic carrier of small interfering RNA (siRNA) with customizable size, pH-responsive degradability and optimized surface population of cell-targeting agents is constructed precisely through a series of interlocked thermodynamically self-regulated processes. This system consists of a unimolecular polyplex core formed from each individual molecule of networked cationic polymer and a multi-functional shell assembled from a rationally designed triblock copolymer. The core-forming polymer of defined size is synthesized via Zeta potential-regulated condensation of branched and linear multi-amine bearing oligomers through pH-responding imidazole conjugated imine linkages. The shell-forming copolymer consists of a multi-carboxyl saccharide end block to guide to the surface assembly, a hydrophobic central block to form an encapsulating layer, and a poly(ethylene glycol) end block equipped with a highly selective active ester for “hooking” various cell-targeting agents. Animal assays confirm the flexibility and convenience of this system to equip with selected functional components for systemic delivery of siRNA.This study introduces a synthetic carrier for siRNA delivery with customizable size, pH-responsive degradability, and flexibility to immobilize selected cell-targeting agents constructed precisely through a series of interlocked thermodynamically self-regulated processes. This system can accomplish all consecutive tasks, such as siRNA encapsulating, target cell recognizing, endosome escaping, siRNA releasing, and self-metabolizing, and be simple in structure and easy to formulate.
      PubDate: 2017-11-30T05:37:51.610932-05:
      DOI: 10.1002/adfm.201703207
       
  • Promoting Active Sites in Core–Shell Nanowire Array as Mott–Schottky
           Electrocatalysts for Efficient and Stable Overall Water Splitting
    • Authors: Jungang Hou; Yiqing Sun, Yunzhen Wu, Shuyan Cao, Licheng Sun
      Abstract: Developing earth-abundant, active, and robust electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a vital challenge for efficient conversion of sustainable energy sources. Herein, metal–semiconductor hybrids are reported with metallic nanoalloys on various defective oxide nanowire arrays (Cu/CuOx, Co/CoOx, and CuCo/CuCoOx) as typical Mott–Schottky electrocatalysts. To build the highway of continuous electron transport between metals and semiconductors, nitrogen-doped carbon (NC) has been implanted on metal–semiconductor nanowire array as core–shell conductive architecture. As expected, NC/CuCo/CuCoOx nanowires arrays, as integrated Mott–Schottky electrocatalysts, present an overpotential of 112 mV at 10 mA cm−2 and a low Tafel slope of 55 mV dec−1 for HER, simultaneously delivering an overpotential of 190 mV at 10 mA cm−2 for OER. Most importantly, NC/CuCo/CuCoOx architectures, as both the anode and the cathode for overall water splitting, exhibit a current density of 10 mA cm−2 at a cell voltage of 1.53 V with excellent stability due to high conductivity, large active surface area, abundant active sites, and the continuous electron transport from prominent synergetic effect among metal, semiconductor, and nitrogen-doped carbon. This work represents an avenue to design and develop efficient and stable Mott–Schottky bifunctional electrocatalysts for promising energy conversion.Nitrogen-doped carbon encapsulated metal-semiconductor nanowire arrays are constructed as integrated core-shell Mott-Schottky electrocatalysts. Due to a prominent synergetic effect of defective oxide nanowires, bimetallic nanoalloys and a nitrogen-doped carbon layer, the NC/CuCo/CuCoOx electrocatalysts approaches 10 mA cm−2 at a cell voltage of 1.53 V. This work opens an avenue to develop efficient and stable Mott-Schottky bifunctional electrocatalysts for energy conversion.
      PubDate: 2017-11-30T05:29:22.458753-05:
      DOI: 10.1002/adfm.201704447
       
  • Synthesis of Highly Luminescent SnO2 Nanocrystals: Analysis of their
           Defect-Related Photoluminescence Using Polyoxometalates as Quenchers
    • Authors: Azzah Dyah Pramata; Koichi Suematsu, Armando Tibigin Quitain, Mitsuru Sasaki, Tetsuya Kida
      Abstract: Colloidal semiconductor nanocrystals (NCs), called quantum dots (QDs), have been intensively studied because of their excellent photoluminescence (PL) quantum yields. However, commercial QDs such as CdSe and InP contain toxic or expensive rare elements, limiting their sustainable use. This study focuses on nontoxic, stable, and cheap tin oxides, and synthesized luminescent SnO2 NCs of ≈2 nm in size by a heating-up method. Tin precursors and diols in a high-boiling point solvent with oleylamine as the surfactant are heated at 240 °C. SnO2 NCs show defect-related photoluminescence at 400–460 nm by excitation at 370 nm, achieving a high quantum yield of more than 60%. The PL intensity is stable even when the NCs are stored in atmospheric air at room temperature for over 1 year. The defect-related emissions of the SnO2 NCs are studied using polyoxometalates (POMs) as the PL quencher. POMs efficiently quench the PL emissions by extracting excited electrons from the conduction band and shallow surface defects. The results reveal that PL emissions from SnO2 NCs are associated with radiative charge recombination via shallow defect levels on the surface and in the bulk, demonstrating the effectiveness of the PL quenching technique using POMs in studying the PL emission mechanism in QDs.This study is carried out with a particular emphasis on the photoluminescence (PL) emission mechanism of SnO2 nanocrystals (NCs). A one-pot synthetic route is developed for SnO2 NCs with controllable sizes, tunable bandgaps, and a high quantum yield. A PL quenching technique is employed to study the defect-related PL emission from the SnO2 NCs using polyoxometalates as quenchers.
      PubDate: 2017-11-30T05:28:40.417976-05:
      DOI: 10.1002/adfm.201704620
       
  • Electronic and Ionic Materials for Neurointerfaces
    • Authors: Marc D. Ferro; Nicholas A. Melosh
      Abstract: Communication between living brain tissue and engineered devices is the key link to understand brain function and restore neurological deficits from disease, injury, and old age. Enabled by new materials and device designs, a new generation of brain interface technologies is replacing bulkier systems, offering lower tissue damage, reduced immunogenicity, and long-term stability. New electrode materials with improved chronic performance and increasing emphasis on multimodal capabilities are being integrated onto ultraflexible and mechanically compliant architectures. As these scale to smaller dimensions and higher channel counts, the goal of bidirectional, single-cell interfaces is nearly within reach. However, promising, long-term reliability, toxicity, and performance of these systems are still largely unknown. Here, the basics of electrode materials and in vivo technologies are reviewed, and recent advances in electronic and ionic materials are highlighted.Neural interface materials with increasing performance and lower tissue damage are being integrated onto new, ultraflexible electrode designs. As these scale to smaller dimensions and higher channel counts, the goal of bidirectional, single-cell interfaces is coming within reach. Here, the basics of in-vivo electrode materials are reviewed, and advances in electronic and ionic materials for brain–machine interfaces are highlighted.
      PubDate: 2017-11-30T05:27:35.557989-05:
      DOI: 10.1002/adfm.201704335
       
  • Revealing the Atomic Defects of WS2 Governing Its Distinct Optical
           Emissions
    • Authors: Yung-Chang Lin; Shisheng Li, Hannu-Pekka Komsa, Li-Jen Chang, Arkady V. Krasheninnikov, Goki Eda, Kazu Suenaga
      Abstract: Defects and their spatial distribution are crucial factors in controlling the electronic and optical properties of semiconductors. By using scanning transmission electron microscopy and electron energy loss spectroscopy, the type of impurities/defects in WS2 subdomains with different optical properties is successfully assigned. A higher population of Cr impurities is found in the W-terminated edge domain, while the S-terminated domain contains more Fe impurities, in accordance with the luminescence characteristics of chemical-vapor-grown WS2 of a hexagonal shape. In agreement with the first-principles calculations, the domains with Cr substitutional dopants exhibit strong trion emission. Fe atoms tend to gather into trimer configuration and introduce deep acceptor levels which compensate the n-type doping and suppress trion emission. It is also discovered that the domain with higher luminescence but smaller defect concentration tends to get oxidized more rapidly and degrade the 2D structure with many triangular holes. Excitons tend to accumulate at the edges of the oxidized triangular holes and results in enhanced PL emission. The findings indicate that choosing stable elements as dopant and controlling the number of specific edge structures within a crystal domain of 2D transitional metal dichalcogenides can be a new route to improve the optical properties of these materials.The photoluminescence property of WS2 is strongly influenced by impurities and defects. Higher emission domain contains higher population of Cr impurities, while the weaker emission domain contains more Fe impurities. Oxidation induced void formations with S-terminated edges tend to enhance the PL emission.
      PubDate: 2017-11-30T05:26:36.212863-05:
      DOI: 10.1002/adfm.201704210
       
  • Polarity-Controlled Attachment of Cytochrome C for High-Performance
           Cytochrome C/Graphene van der Waals Heterojunction Photodetectors
    • Authors: Maogang Gong; Puja Adhikari, Youpin Gong, Ti Wang, Qingfeng Liu, Bhupal Kattel, Wai-Yim Ching, Wai-Lun Chan, Judy Z. Wu
      Abstract: Biomolecule/graphene van der Waals heterojunction provides a generic platform for designing high-performance, flexible, and scalable optoelectronics. A key challenge is, in controllable attachment, the biomolecules to form a desired interfacial electronic structure for a high-efficiency optoelectronic process of photoabsorption, exciton dissociation into photocarriers, carrier transfer, and transport. Here, it is shown that a polarity-controlled attachment of the Cytochrome c (Cyt c) biomolecules can be achieved on the channel of graphene field effect transistors (GFET). High-efficiency charge transfer across the formed Cyt c/graphene interface is demonstrated when Cyt c attaches with positively charged side to GFET as predicted by molecular dynamics simulation and confirmed experimentally. This Cyt c/GFET van der Waals heterojunction nanohybrid photodetector exhibits a spectral photoresponsivity resembling the absorption spectrum of the Cyt c, confirming the role of Cty c as the photosensitizer in the device. The high visible photoresponsivity up to 7.57 × 104 A W−1 can be attributed to the high photoconductive gain in exceeding 105 facilitated by the high carrier mobility in graphene. This result therefore demonstrates a viable approach in synthesis of the biomolecule/graphene van der Waals heterojunction optoelectronics using polarity-controlled biomolecule attachment, which can be expanded for on-chip printing of high-performance molecular optoelectronics.A polarity-controlled attachment of the Cytochrome c (Cyt c) biomolecules can be achieved on the channel of graphene field effect transistors (GFET). High-efficiency charge transfer across the formed Cyt c/graphene van der Waals interface is demonstrated. This Cyt c/GFET photodetector exhibits a high photoresponsivity up to 7.57 × 104 A W−1 and a fast response time of 5.2 ms.
      PubDate: 2017-11-30T05:26:11.287488-05:
      DOI: 10.1002/adfm.201704797
       
  • Pseudohalide-Induced Recrystallization Engineering for CH3NH3PbI3 Film and
           Its Application in Highly Efficient Inverted Planar Heterojunction
           Perovskite Solar Cells
    • Authors: Hua Dong; Zhaoxin Wu, Jun Xi, Xiaobao Xu, Lijian Zuo, Ting Lei, Xingang Zhao, Lijun Zhang, Xun Hou, Alex K.-Y. Jen
      Abstract: High crystallinity and compactness of the active layer is essential for metal-halide perovskite solar cells. Here, a simple pseudohalide-induced film retreatment technology is developed as the passivation for preformed perovskite film. It is found that the retreatment process yields a controllable decomposition-to-recrystallization evolution of the perovskite film. Corresponding, it remarkably enlarges the grain size of the film in all directions, as well as improving the crystallinity and hindering the trap density. Meanwhile, owing to an intermediate catalytic effect of the pseudohalide compound (NH4SCN), no crystal orientation changing and no impurity introduction in the modified film. By integrating the modified perovskite film into the planar heterojunction solar cells, a champion power conversion efficiency of 19.44% with a stabilized output efficiency of 19.02% under 1 sun illumination is obtained, exhibiting a negligible current density–voltage hysteresis. Moreover, such a facile and low-temperature film retreatment approach guarantees the application in flexible devices, showing a best power conversion efficiency of 17.04%.A facile and low-temperature pseudohalide-induced postprocessing technology is developed to improve the crystallinity and compactness of the perovskite active layer by integrating the modified perovskite film into the planar heterojunction solar cells, a best efficiency of 19.44%, with a negligible current density–voltage hysteresis. Meanwhile, successful application is obtained in flexible devices, showing a best power conversion efficiency of 17.04%.
      PubDate: 2017-11-30T05:21:03.314633-05:
      DOI: 10.1002/adfm.201704836
       
  • From 3D ZIF Nanocrystals to Co–Nx/C Nanorod Array Electrocatalysts for
           ORR, OER, and Zn–Air Batteries
    • Authors: Ibrahim Saana Amiinu; Xiaobo Liu, Zonghua Pu, Wenqiang Li, Qidong Li, Jie Zhang, Haolin Tang, Haining Zhang, Shichun Mu
      Abstract: Designing a highly active electrocatalyst with optimal stability at low cost is must and non-negotiable if large-scale implementations of fuel cells are to be fully realized. Zeolitic-imidazolate frameworks (ZIFs) offer rich platforms to design multifunctional materials due to their flexibility and ultrahigh surface area. Herein, an advanced Co–Nx/C nanorod array derived from 3D ZIF nanocrystals with superior electrocatalytic activity and stability toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) compared to commercial Pt/C and IrO2, respectively, is synthesized. Remarkably, as a bifunctional catalyst (Ej = 10 (OER) − E1/2 (ORR) ≈ 0.65 V), it further displays high performance of Zn–air batteries with high cycling stability even at a high current density. Such supercatalytic properties are largely attributed to the synergistic effect of the chemical composition, high surface area, and abundant active sites of the nanorods. The activity origin is clarified through post oxygen reduction X-ray photoelectron spectroscopy analysis and density functional theory studies. Undoubtedly, this approach opens a new avenue to strategically design highly active and performance-oriented electrocatalytic materials for wider electrochemical energy applications.A highly active bifunctional electrocatalyst is designed via a structural transformation of 3D ZIF nanocrystals into an array of 1D metal/N functionalized carbon nanorod frameworks. The obtained catalyst exhibits superior bifunctional activity and stability toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), leading to high Zn-air battery performances compared to the state-of-the-art counterparts.
      PubDate: 2017-11-29T02:22:01.900975-05:
      DOI: 10.1002/adfm.201704638
       
  • Self-Supported 3D Array Electrodes for Sodium Microbatteries
    • Authors: Jiangfeng Ni; Liang Li
      Abstract: The ever-increasing demand for autonomous microelectronic devices necessitates on-chip miniature energy storage systems such as microbatteries. Conventional microbatteries adopt planar thin-film electrodes that display limited areal energy and power due to their undesired coupling. To achieve high energy and power simultaneously, employment of 3D array electrodes has proven indispensable. Adoption of 3D electrodes has become a fashionable trend in lithium microbatteries during the last decade. This trend also occurs in sodium batteries, which are an important alternative to the current lithium system owing to the potentially high power and wide availability of sodium. In this perspective, state-of-the-art progress in design and application of 3D arrays for sodium microbatteries are summarized. Specifically, emphasis is placed on material strategies to efficiently address the intrinsic limitations of pristine arrays such as transportation, activity, and stability. Future challenges and prospects in this field are also discussed, and the importance of integrating novel concepts into 3D electrode fabrication, characterization, and modeling to meet practical requirements is highlighted.Self-supported 3D electrode arrays offer the advantage to improve the areal energy and power simultaneously, and thus are suitable for microbatteries. In this perspective, the cutting-edge advancements in design, fabrication, and modification of sodium array electrodes for microbatteries are summarized. Specific emphasis is placed on materials strategies that are capable of tailoring the property and electrochemistry of array electrodes.
      PubDate: 2017-11-29T02:16:28.44596-05:0
      DOI: 10.1002/adfm.201704880
       
  • A Multicolor Chameleon DNA-templated Silver Nanocluster and Its
           Application for Ratiometric Fluorescence Target Detection with Exponential
           Signal Response
    • Authors: Weijun Zhou; Jinbo Zhu, Daoqing Fan, Ye Teng, Xiaoqing Zhu, Shaojun Dong
      Abstract: For the first time, a novel type of chameleon DNA-templated silver nanocluster (AgNC) is found whose fluorescence color can be switched among yellow, orange, and red by the regulation of complementary DNA, nonfluorescent assistant AgNC as well as Mg2+. AgNC templated by A20-C55 (A20-C55-NC) possesses strong yellow fluorescence (Y signal) in phosphate buffer solution. When approaching to the nonfluorescent assistant AgNC through template hybridization, Y signal decreases while a new red emission (R signal) rises, leading to a dramatic color change of AgNC solution from yellow to red. On the other hand, hybridization of A20-C55-NC with complementary DNA (T20) largely enhances the Y signal while A20-C55-NC shows R and Y signal with equal intensity simultaneously in the presence of Mg2+. Therefore, the chameleon AgNC achieves controllable multicolor fluorescence variation. Based on above mechanism, a series of ratiometric analysis platforms are constructed for DNA target detection. Surprisingly, the ratiometric probes demonstrate an exponential growth of signal response with nanomolar sensitivity whether in double-stranded or hairpin-shaped structure. Accordingly, this universal ratiometric analysis platform possesses low background, large signal variation in a narrow concentration range, which presents obvious advantages over most of previous DNA detection strategies that are based on DNA-templated AgNC.Herein, a novel type of chameleon DNA-templated AgNC whose fluorescence color can be switched among yellow, orange and red by the regulation of complementary DNA, nonfluorescent assistant AgNC as well as Mg2+ is found. Therefore, ratiometric analysis platforms that possess low background and large signal variation in a narrow concentration range have been constructed for DNA target detection.
      PubDate: 2017-10-27T02:17:45.079602-05:
      DOI: 10.1002/adfm.201704092
       
  • Traceable Nanoparticles with Spatiotemporally Controlled Release Ability
           for Synergistic Glioblastoma Multiforme Treatment
    • Authors: Zhiguo Lu; Yan Li, Yuanjie Shi, Yanhui Li, Zuobing Xiao, Xin Zhang
      Abstract: Doxorubicin (DOX), one of the most widely used clinical antineoplastics, has ineffective therapeutic efficacy on glioblastoma multiforme (GBM) with extremely short survival time due to many obstacles such as blood–brain barrier (BBB), tumor angiogenesis, and glioblastoma stem cells (GSCs). To overcome, biocompatible nanoparticles named CARD-B6 loading three clinical drugs are developed. Unlike other nanomedicines, CARD-B6, with the ability of spatiotemporally controlled release, maximize the effectiveness of DOX. (1) After CARD-B6 cross the BBB via B6, combretastatin A4 that is first released via protonation of poly (β-amino ester) specifically destroys angiogenesis to facilitate the interaction between GBM and CARD-B6. (2) Internalized into glioblastoma cells later, DOX is released via the breakage of amido bond to induce apoptosis, which is facilitated by the simultaneously released all-trans retinoic acid (ATRA). (3) After endocytosis into GSCs, the rapidly released ATRA induces the GSCs differentiation and downregulates the survival pathways, which enhances the sensitivity of GSCs to the subsequently released DOX. This synergistic antitumor effect significantly extends survival time of GBM mouse model. CARD-B6 are traced by superparamagnetic iron oxide nanocubes with high r2 relaxivity for magnetic resonance imaging. Therefore, the traceable CARD-B6 with spatiotemporally controlled release ability are emerging as a powerful platform for GBM treatment.CARD-B6 with spatiotemporally controlled release ability are successfully fabricated. CARD-B6 deliver CA4, ATRA, and Doxorubicin (DOX) to their corresponding active sites sequentially after across blood–brain barrier. The nanoparticles overcome the barriers of DOX for glioblastoma multiforme (GBM) therapy and significantly enhance the therapeutic efficacy of DOX with extended survival time, holding great potential for GBM therapy.
      PubDate: 2017-10-27T02:17:21.304789-05:
      DOI: 10.1002/adfm.201703967
       
  • Effective Prevention of Charge Trapping in Graphitic Carbon Nitride with
           Nanosized Red Phosphorus Modification for Superior Photo(electro)catalysis
           
    • Authors: Lin Jing; Ruixue Zhu, David Lee Phillips, Jimmy C. Yu
      Abstract: The high occurrence of trapped unreactive charges due to chemical defects seriously affects the performance of g-C3N4 in photocatalytic applications. This problem can be overcome by introducing ultrasmall red phosphorus (red P) crystals on g-C3N4 sheets. The elemental red P atoms reduce the number of defects in the g-C3N4 structure by forming new chemical bonds for much more effective charge separation. The product shows significantly enhanced photocatalytic activity toward hydrogen production. To the best of our knowledge, the hydrogen evolution rate obtained on this hybrid should be the highest among all P-containing g-C3N4 photocatalysts reported so far. The trapping and detrapping processes in this red P/g-C3N4 system are thoroughly revealed by using time-resolved transient absorption spectroscopy.Chemical bonding of elemental red phosphorus (red P) remediates the chemical defects in g-C3N4 structure. This would effectively suppress the charges trapping and prolong the lifetime of active charges in g-C3N4 during the photocatalytic applications. This optimized red P/g-C3N4 composite holds the highest record toward photocatalytic hydrogen production in the reported P-containing g-C3N4 systems to date.
      PubDate: 2017-10-25T10:07:55.258374-05:
      DOI: 10.1002/adfm.201703484
       
  • Graphene Oxide-Based Lamella Network for Enhanced Sound Absorption
    • Authors: Md Julker Nine; Md Ayub, Anthony C. Zander, Diana N. H. Tran, Benjamin S. Cazzolato, Dusan Losic
      Abstract: Noise is an environmental pollutant with recognized impacts on the psychological and physiological health of humans. Many porous materials are often limited by low sound absorption over a broad frequency range, delicacy, excessive weight and thickness, poor moisture insulation, high temperature instability, and lack of readiness for high volume commercialization. Herein, an efficient and robust lamella-structure is reported as an acoustic absorber based on self-assembled interconnected graphene oxide (GO) sheets supported by a grill-shaped melamine skeleton. The fabricated lamella structure exhibits ≈60.3% enhancement over a broad absorption band between 128 and 4000 Hz (≈100% at lower frequencies) compared to the melamine foam. The enhanced acoustic absorption is identified to be structure dependent regardless of the density. The sound dissipation in the open-celled structure is due to the viscous and thermal losses, whereas it is predominantly tortuosity in wave propagation and enhanced surface area for the GO-based lamella. In addition to the enhanced acoustic absorption and mechanical robustness, the lamella provides superior structural functionality over many conventional sound absorbers including, moisture/mist insulation and fire retardancy. The fabrication of this new sound absorber is inexpensive, scalable and can be adapted for extensive applications in commercial, residential, and industrial building structures.A robust and light density lamella structure is developed based on self-assembly of graphene-oxide. The incorporation of this unique structure in an open cell network showed ~60.3% enhancement in acoustic absorption between 128 Hz and 4000 Hz. The moisture insulation and fire-retardancy further reinforce their functionality for using in adverse environments including high humidity, under water and fire risks conditions.
      PubDate: 2017-10-23T06:38:29.199541-05:
      DOI: 10.1002/adfm.201703820
       
  • Highly Periodic Metal Dichalcogenide Nanostructures with Complex Shapes,
           High Resolution, and High Aspect Ratios
    • Authors: Sungwoo Jang; Seon Joon Kim, Hyeong-Jun Koh, Doo Hyung Jang, Soo-Yeon Cho, Hee-Tae Jung
      Abstract: The development of high resolution, high aspect ratio metal dichalcogenide nanostructures is one of the most important issues in 2D material researchers due to the potential to exploit their properties into high performance devices. In this study, for the first time a way of fabricating metal dichalcogenide nanostructures with high resolution (120) by chemical vapor deposition assisted secondary sputtering phenomenon is reported. This approach can universally synthesize various types of metal dichalcogenides including MoS2, WS2, and SnS2, implying the possibility for further utilization with selenides and tellurides. Also, this method can produce highly periodic complex patterns such as hole–cylinder, concentric rings, and line patterns, which are unprecedented in previous reports. The feature size and aspect ratio of the metal dichalcogenide structures can be manipulated by controlling the dimensions of the photoresist prepatterns, while the pattern resolution and layer orientation can be manipulated by controlling the thickness of the deposited metal film. It is demonstrated that nanostructures with high resolution and high aspect ratio significantly improve gas-sensing properties compared with previous metal dichalcogenide films. It is believed that the method can be a foundation for synthesizing various materials with complex patterns for future applications.A universal way for fabricating periodic metal dichalcogenide nanostructures with high resolution (120), and complex shapes is developed for the first time. Various metal dichalcogenides are demonstrated in this work, and nanostructures of MoS2, WS2, and SnS2 with serpentine, line, hole–cylinder, and concentric patterns are fabricated over a large area.
      PubDate: 2017-10-23T06:31:58.006753-05:
      DOI: 10.1002/adfm.201703842
       
  • Mercury-Mediated Organic Semiconductor Surface Doping Monitored by
           Electrolyte-Gated Field-Effect Transistors
    • Authors: Qiaoming Zhang; Francesca Leonardi, Stefano Casalini, Marta Mas-Torrent
      Abstract: Surface doping allows tuning the electronic structure of semiconductors at near-surface regime and is normally accomplished through the deposition of an ultrathin layer on top or below the host material. Surface doping is particularly appealing in organic field-effect transistors (OFETs) where charge transport takes place at the first monolayers close to the dielectric surface. However, due to fabrication restrictions that OFET architecture imparts, this is extremely challenging. Here, it is demonstrated that mercury cations, Hg2+, can be exploited to control doping levels at the top surface of a thin film of a p-type organic semiconductor blended with polystyrene. Electrolyte- or water-gated field-effect transistors, which have its conductive channel at the top surface of the organic thin film, turn out to be a powerful tool for monitoring the process. A positive shift of the threshold voltage is observed in the devices upon Hg2+ exposure. Remarkably, this interaction has been proved to be specific to Hg2+ with respect to other divalent cations and sensitive down to nanomolar concentrations. Hence, this work also opens new perspectives for employing organic electronic transducers in portable sensors for the detection of an extremely harmful water pollutant without the need of using specific receptors.A novel approach for surface doping a p-type organic semiconductor is realized by exploiting the redox reaction that occurs between Hg2+ and the semiconductor in aqueous media. The device reveals high sensitivity and selectivity toward Hg2+ with respect to other divalent metal cations, which is highly appealing for the development of in-field sensors.
      PubDate: 2017-10-23T06:30:39.328866-05:
      DOI: 10.1002/adfm.201703899
       
  • Effects of Defects on the Temperature-Dependent Thermal Conductivity of
           Suspended Monolayer Molybdenum Disulfide Grown by Chemical Vapor
           Deposition
    • Authors: Milad Yarali; Xufei Wu, Tushar Gupta, Debjit Ghoshal, Lixin Xie, Zhuan Zhu, Hatem Brahmi, Jiming Bao, Shuo Chen, Tengfei Luo, Nikhil Koratkar, Anastassios Mavrokefalos
      Abstract: It is understood that defects of the atomic arrangement of the lattice in 2D molybdenum disulfide (MoS2) grown by chemical vapor deposition (CVD) can have a profound effect on the electronic and optical properties. Beyond these it is a major prerequisite to also understand the fundamental effect of such defects on phonon transport, to guarantee the successful integration of MoS2 into the solid-state devices. A comprehensive joint experiment-theory investigation to explore the effect of lattice defects on the thermal transport of the suspended MoS2 monolayer grown by CVD is presented. The measured room temperature thermal conductivity values are 30 ± 3.3 and 35.5 ± 3 W m−1 K−1 for two samples, which are more than two times smaller than that of their exfoliated counterpart. High-resolution transmission electron microscopy shows that these CVD-grown samples are polycrystalline in nature with low angle grain boundaries, which is primarily responsible for their reduced thermal conductivity. Higher degree of polycrystallinity and aging effects also result in smoother temperature dependency of thermal conductivity (κ) at temperatures below 100 K. First-principles lattice dynamics simulations are carried out to understand the role of defects such as isotopes, vacancies, and grain boundaries on the phonon scattering rates of our CVD-grown samples.The lattice structure–thermal conductivity relation of MoS2 monolayer grown by chemical vapor deposition is investigated in a wide temperature range using a suspended microdevice with integrated resistance thermometers. Higher degree of polycrystallinity leads to smoother temperature dependency at temperatures below 100 K. The observations are explained by the first-principles lattice dynamics calculations.
      PubDate: 2017-10-23T00:40:41.024662-05:
      DOI: 10.1002/adfm.201704357
       
  • Asymmetric Tunable Photonic Bandgaps in Self-Organized 3D Nanostructure of
           Polymer-Stabilized Blue Phase I Modulated by Voltage Polarity
    • Authors: Meng Wang; Cheng Zou, Jian Sun, Lanying Zhang, Ling Wang, Jiumei Xiao, Fasheng Li, Ping Song, Huai Yang
      Abstract: Electrically responsive photonic crystals represent one of the most promising intelligent materials for technological applications in optoelectronics. In this research, a polymer-stabilized blue phase (PSBP) I film with the self-organized 3D nanostructure is fabricated, and an electrically tunable photonic bandgap (PBG) is achieved. Interestingly, the large-scale shift of the PBG covering the entire visible spectrum is found to be asymmetric and can be modulated by the polarity and magnitude of bias voltage. Moreover, to demonstrate the usability in optical devices, blue phase lasers are developed by doping the PSBP material with fluorescent dyes. And mirrorless lasing emission with electrically tunable wavelength is observed. This self-assembled soft material is prospective to produce large-scale electrically responsive photonic crystals in facile fabrication process and has enormous potential applications in intelligent optoelectronic devices, such as 3D tunable lasers, reflective full-color displays, or photonic integrated circuits.Self-organized 3D nanostructure of polymer-stabilized blue phase I with electric-induced reversible tuning of photonic bandgap covering the visible spectrum is developed. The shifting of the photonic bandgaps can be facilely modulated by the polarity and magnitude of applied direct current field, and the practical application for electrically tunable lasers is demonstrated.
      PubDate: 2017-10-23T00:31:48.121321-05:
      DOI: 10.1002/adfm.201702261
       
  • Recent Advances in Sensing Applications of Graphene Assemblies and Their
           Composites
    • Authors: Tran Thanh Tung; Md J. Nine, Melinda Krebsz, Tibor Pasinszki, Campbell J. Coghlan, Diana N. H. Tran, Dusan Losic
      Abstract: Development of next-generation sensor devices is gaining tremendous attention in both academia and industry because of their broad applications in manufacturing processes, food and environment control, medicine, disease diagnostics, security and defense, aerospace, and so forth. Current challenges include the development of low-cost, ultrahigh, and user-friendly sensors, which have high selectivity, fast response and recovery times, and small dimensions. The critical demands of these new sensors are typically associated with advanced nanoscale sensing materials. Among them, graphene and its derivatives have demonstrated the ideal properties to overcome these challenges and have merged as one of the most popular sensing platforms for diverse applications. A broad range of graphene assemblies with different architectures, morphologies, and scales (from nano-, micro-, to macrosize) have been explored in recent years for designing new high-performing sensing devices. Herein, this study presents and discusses recent advances in synthesis strategies of assembled graphene-based superstructures of 1D, 2D, and 3D macroscopic shapes in the forms of fibers, thin films, and foams/aerogels. The fabricated state-of-the-art applications of these materials in gas and vapor, biomedical, piezoresistive strain and pressure, heavy metal ion, and temperature sensors are also systematically reviewed and discussed, and their sensing performance is compared.Graphene assemblies with different 1D, 2D, and 3D architectures are extensively used to construct a broad range of sensing devices with advanced functionalities and performances. The chemical approaches play vital roles not only in assembling graphene into desired macroscopic structures, but also in enhancing sensing performance of gas/vapor, bio-, piezoresistive, and other sensor devices.
      PubDate: 2017-10-20T06:23:04.412403-05:
      DOI: 10.1002/adfm.201702891
       
  • Hematite Photoanodes: Synergetic Enhancement of Light Harvesting and
           Charge Management by Sandwiched with Fe2TiO5/Fe2O3/Pt Structures
    • Authors: Lei Wang; Nhat Truong Nguyen, Xiaojuan Huang, Patrik Schmuki, Yingpu Bi
      Abstract: Efficient charge separation and transport as well as high light absorption are key factors that determine the efficiency of photoelectrochemical (PEC) water splitting devices. Here, a PEC device consisting of a hematite nanoporous film deposited on Pt nanopillars, followed by the decoration with an Fe2TiO5 passivation layer, is designed and fabricated. This structure can largely improve the light absorption in the composite materials, and significantly enhance the water oxidation performance of hematite photoanodes. The Fe2TiO5 thin shell and Pt underlayer significantly improve the interfacial charge transfer while minimizing the hole-migration length in Fe2O3 photoanodes, leading to a drastically increased photocurrent density. Specially, the Fe2TiO5/Fe2O3/Pt photoanode yields an excellent photoresponse for PEC water splitting reactions with 1.0 and 2.4 mA cm−2 obtained at 1.23 and 1.6 VRHE under AM 1.5G illumination in 1 m KOH. The resulting photocurrents are 2.5 times enhanced compared to a pristine Fe2O3 photoanode of the same geometry. These results demonstrate a synergistic charge transfer effect of Fe2TiO5 and Pt layers on hematite for the improvement of PEC water oxidation.Synergetic enhancement of light harvesting and charge separation. The formation of a Fe2TiO5 thin shell and a Pt underlayer on hematite photoanodes largely improves light absorption in the composite material, and also significantly enhances the water oxidation performance. The Fe2TiO5 thin shell and Pt underlayer significantly improve the interfacial and surface charge separation efficiencies with minimized influence on the hole-migration property of Fe2O3 photoanodes.
      PubDate: 2017-10-20T06:17:08.434664-05:
      DOI: 10.1002/adfm.201703527
       
  • Hierarchical Porous NC@CuCo Nitride Nanosheet Networks: Highly Efficient
           Bifunctional Electrocatalyst for Overall Water Splitting and Selective
           Electrooxidation of Benzyl Alcohol
    • Authors: Jian Zheng; Xianlang Chen, Xing Zhong, Suiqin Li, Tianzhu Liu, Guilin Zhuang, Xiaonian Li, Shengwei Deng, Donghai Mei, Jian-Guo Wang
      Abstract: Highly active and stable bifunctional electrocatalysts for overall water splitting are important for clean and renewable energy technologies. The development of energy-saving electrocatalysts for hydrogen evolution reaction (HER) by replacing the sluggish oxygen evolution reaction (OER) with a thermodynamically favorable electrochemical oxidation (ECO) reaction has attracted increasing attention. In this study, a self-supported, hierarchical, porous, nitrogen-doped carbon (NC)@CuCo2Nx/carbon fiber (CF) is fabricated and used as an efficient bifunctional electrocatalyst for both HER and OER in alkaline solutions with excellent activity and stability. Moreover, a two-electrode electrolyzer is assembled using the NC@CuCo2Nx/CF as an electrocatalyst at both cathode and anode electrodes for H2 production and selective ECO of benzyl alcohol with high conversion and selectivity. The excellent electrocatalytic activity is proposed to be mainly due to the hierarchical architecture beneficial for exposing more catalytic active sites, enhancing mass transport. Density functional theoretical calculations reveal that the adsorption energies of key species can be modulated due to the synergistic effect between CoN and CuN. This work provides a reference for the development of high-performance bifunctional electrocatalysts for simultaneous production of H2 and high-value-added fine chemicals.Hierarchical porous nitrogen-doped carbon@CuCo2Nx/carbon fiber serving as an efficient bifunctional electrocatalyst for overall water splitting and selective electrooxidation of benzyl alcohol with excellent activity and stability is reported. The outstanding electrocatalytic performance is mainly due to the hierarchical architecture and the synergistic effects between the Co5.47N, Cu3N nanoparticles.
      PubDate: 2017-10-20T06:04:19.856462-05:
      DOI: 10.1002/adfm.201704169
       
  • Triplet Transfer Mediates Triplet Pair Separation during Singlet Fission
           in 6,13-Bis(triisopropylsilylethynyl)-Pentacene
    • Authors: Christopher Grieco; Grayson S. Doucette, Jason M. Munro, Eric R. Kennehan, Youngmin Lee, Adam Rimshaw, Marcia M. Payne, Nichole Wonderling, John E. Anthony, Ismaila Dabo, Enrique D. Gomez, John B. Asbury
      Abstract: Triplet population dynamics of solution cast films of isolated polymorphs of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) provide quantitative experimental evidence that triplet excitation energy transfer is the dominant mechanism for correlated triplet pair (CTP) separation during singlet fission. Variations in CTP separation rates are compared for polymorphs of TIPS-Pn with their triplet diffusion characteristics that are controlled by their crystal structures. Since triplet energy transfer is a spin-forbidden process requiring direct wavefunction overlap, simple calculations of electron and hole transfer integrals are used to predict how molecular packing arrangements would influence triplet transfer rates. The transfer integrals reveal how differences in the packing arrangements affect electronic interactions between pairs of TIPS-Pn molecules, which are correlated with the relative rates of CTP separation in the polymorphs. These findings suggest that relatively simple computations in conjunction with measurements of molecular packing structures may be used as screening tools to predict a priori whether new types of singlet fission sensitizers have the potential to undergo fast separation of CTP states to form multiplied triplets.Ultrafast spectroscopy of 6,13-bis(triisopropylsilylethynyl)-pentacene polymorphs reveals triplet transfer as the mechanism of correlated triplet pair separation in singlet fission. Crystal structures, solved through both X-ray and computational methods, explain differences in their triplet separation characteristics. Charge transfer integrals form a metric for assessing triplet pair separation, codifying a new approach to a priori screening of emerging singlet fission materials.
      PubDate: 2017-10-20T06:00:56.175482-05:
      DOI: 10.1002/adfm.201703929
       
  • Glutathione-Activatable and O2/Mn2+-Evolving Nanocomposite for Highly
           Efficient and Selective Photodynamic and Gene-Silencing Dual Therapy
    • Authors: Dinggeng He; Luo Hai, Xing He, Xue Yang, Hung-Wing Li
      Abstract: Photodynamic therapy (PDT) has been applied in cancer treatment by converting O2 into reactive singlet oxygen (1O2) to kill cancer cells. However, the effectiveness of PDT is limited by the fact that tumor hypoxia causes an inadequate O2 supply, and the overexpressed glutathione (GSH) in cancer cells consumes reactive oxygen species. Herein, a multifunctional hybrid system is developed for selective and highly efficient PDT as well as gene-silencing therapy using a novel GSH-activatable and O2/Mn2+-evolving nanocomposite (GAOME NC). This system consists of honeycomb MnO2 (hMnO2) nanocarrier loaded with catalase, Ce6, and DNAzyme with folate label, which can specifically deliver payloads into cancer cells. Once endocytosed, hMnO2 carriers are reduced by the overexpressed GSH to Mn2+ ions, resulting in the reduction of GSH level and disintegration of GAOME NC. The released catalases then trigger the breakdown of endogenous H2O2 to generate O2, which is converted by the excited Ce6 into 1O2. The self-sufficiency of O2 and consumption of GSH effectively enhance the PDT efficacy. Moreover, DNAzyme is freed for gene silencing in the presence of self-generated Mn2+ ions as cofactors. The rational synergy of enhanced PDT and gene-silencing therapy remarkably improve the in vitro and in vivo therapeutic efficacy of cancers.A cell-specific, glutathione (GSH)-activatable, and O2/Mn2+-evolving nanocomposite consisting of honeycomb MnO2 carrier carrying catalase, Ce6, and DNAzyme with folate label is developed for not only the enhanced photodynamic therapy by both self-sufficiency of O2 and the depletion of cellular GSH induced by MnO2 carrier, but also the coupled Mn2+-DNAzyme-mediated gene-silencing therapy with the self-generated Mn2+ ions as cofactors.
      PubDate: 2017-10-20T05:57:24.456547-05:
      DOI: 10.1002/adfm.201704089
       
  • High Reversible Pseudocapacity in Mesoporous Yolk–Shell Anatase
           TiO2/TiO2(B) Microspheres Used as Anodes for Li-Ion Batteries
    • Authors: Hao Wei; Erwin F. Rodriguez, Anthony F. Hollenkamp, Anand I. Bhatt, Dehong Chen, Rachel A. Caruso
      Abstract: As an anode material for lithium-ion batteries, titanium dioxide (TiO2) shows good gravimetric performance (336 mAh g−1 for LiTiO2) and excellent cyclability. To address the poor rate behavior, slow lithium-ion (Li+) diffusion, and high irreversible capacity decay, TiO2 nanomaterials with tuned phase compositions and morphologies are being investigated. Here, a promising material is prepared that comprises a mesoporous “yolk–shell” spherical morphology in which the core is anatase TiO2 and the shell is TiO2(B). The preparation employs a NaCl-assisted solvothermal process and the electrochemical results indicate that the mesoporous yolk–shell microspheres have high specific reversible capacity at moderate current (330.0 mAh g−1 at C/5), excellent rate performance (181.8 mAh g−1 at 40C), and impressive cyclability (98% capacity retention after 500 cycles). The superior properties are attributed to the TiO2(B) nanosheet shell, which provides additional active area to stabilize the pseudocapacity. In addition, the open mesoporous morphology improves diffusion of electrolyte throughout the electrode, thereby contributing directly to greatly improved rate capacity.Mesoporous anatase TiO2 yolk–TiO2(B) shell microspheres are synthesized via a solvothermal process. Porous shells of thin TiO2(B) nanosheets are separated by a gap from the anatase TiO2 cores. These microspheres show a high reversible capacity and long-term cyclability as active anode materials in lithium-ion batteries.
      PubDate: 2017-10-16T06:16:08.337357-05:
      DOI: 10.1002/adfm.201703270
       
  • High Performance PbS Colloidal Quantum Dot Solar Cells by Employing
           Solution-Processed CdS Thin Films from a Single-Source Precursor as the
           Electron Transport Layer
    • Authors: Long Hu; Robert J. Patterson, Yicong Hu, Weijian Chen, Zhilong Zhang, Lin Yuan, Zihan Chen, Gavin J. Conibeer, Gang Wang, Shujuan Huang
      Abstract: CdS thin films are a promising electron transport layer in PbS colloidal quantum dot (CQD) photovoltaic devices. Some traditional deposition techniques, such as chemical bath deposition and RF (radio frequency) magnetron sputtering, have been employed to fabricate CdS films and CdS/PbS CQD heterojunction photovoltaic devices. However, their power conversion efficiencies (PCEs) are moderate compared with ZnO/PbS and TiO2/PbS heterojunction CQD solar cells. Here, efficiencies have been improved substantially by employing solution-processed CdS thin films from a single-source precursor. The CdS film is deposited by a straightforward spin-coating and annealing process, which is a simple, low-cost, and high-material-usage fabrication process compared to chemical bath deposition and RF magnetron sputtering. The best CdS/PbS CQD heterojunction solar cell is fabricated using an optimized deposition and air-annealing process achieved over 8% PCE, demonstrating the great potential of CdS thin films fabricated by the single-source precursor for PbS CQDs solar cells.A heterojunction PbS quantum dot solar cell with an efficiency over 8% is achieved by optimizing CdS electron transport layer deposited by a simple single-source precursor spin-coating process. The optimized band alignment of the device improves the short circuit current and fill factor.
      PubDate: 2017-10-16T06:15:43.289067-05:
      DOI: 10.1002/adfm.201703687
       
  • InVADE: Integrated Vasculature for Assessing Dynamic Events
    • Authors: Benjamin Fook Lun Lai; Locke Davenport Huyer, Rick Xing Ze Lu, Stasja Drecun, Milica Radisic, Boyang Zhang
      Abstract: Drug screening with simplified 2D cell culture and relevant animal testing fail to predict clinical outcomes. With the rising cost of drug development, predictive 3D tissue models with human cells are in urgent demand. Establishing vascular perfusion of 3D tissues has always been a challenge, but it is necessary to mimic drug transport and to capture complex interorgan crosstalk. Here, a versatile multiwell plate is presented empowered by built-in microfabricated vascular scaffolds that define the vascular space and support self-assembly of various parenchymal tissues. In this configuration, assembly and organ-specific function of a metabolically active liver, a free-contracting cardiac muscle, and a metastatic solid tumor are demonstrated, tracking organ function using noninvasive analysis techniques. By linking the 3D tumor and the liver tissue in series, it is demonstrated that the presence of liver tissue is crucial to correctly reveal the efficacy of a chemotherapeutic drug, Tegafur. Furthermore, the complete cancer metastasis cascade is demonstrated across multiple organs, where cancer cells escaping from the solid tumor can invade a distant liver tissue connected through a continuous vascular interface. This combinatory use of microfabricated scaffold onto a standard cell culturing platform can offer important insights into the mechanics of complex interorgan biological events.InVADE, integrated vasculature for assessing dynamic events, is a user-friendly 96-well plate platform that utilizes a single vascularized scaffold to recapture in- vivo- like drug transfer and cell trafficking between multiple organs. This platform can offer not only highly reproducible data in drug target validation but also further unlock pathways involved in complex multiorgan biological events.
      PubDate: 2017-10-16T06:11:31.25339-05:0
      DOI: 10.1002/adfm.201703524
       
  • A General Strategy for Stretchable Microwave Antenna Systems using
           Serpentine Mesh Layouts
    • Authors: Tammy Chang; Yuji Tanabe, Charles C. Wojcik, Alex C. Barksdale, Sage Doshay, Zhenya Dong, Hao Liu, Maoyi Zhang, Yuli Chen, Yewang Su, Thomas H. Lee, John S. Ho, Jonathan A. Fan
      Abstract: Wireless functionality is essential for the implementation of wearable systems, but its adaptation in stretchable electronic systems has had limited success. In this paper, the electromagnetic properties of stretchable serpentine mesh-based systems is studied, and this general strategy is used to produce high-performance stretchable microwave systems. Stretchable mechanics are enabled by converting solid metallic sections in conventional systems to subwavelength-scale serpentine meshes, followed by bonding to an elastomeric substrate. Compared to prior implementations of serpentine meshes in microwave systems, this conversion process is extended to arbitrary planar layouts, including those containing curvilinear shapes. A detailed theoretical analysis is also performed and a natural tradeoff is quantified between the stretching mechanics and microwave performance of these systems. To explore the translation of these concepts from theory to experiment, two types of stretchable microwave devices are fabricated and characterized: a stretchable far-field dipole antenna for communications and a stretchable midfield phased surface for the wireless powering of biomedical implanted devices.A general strategy for producing high-performance stretchable microwave systems using subwavelength-scale serpentine mesh layouts is presented. A detailed theoretical analysis is used to quantify the natural tradeoff between the stretching mechanics and microwave performance of these systems. To explore the translation of these concepts from theory to experiment, a stretchable far-field dipole antenna and midfield phased surface are demonstrated.
      PubDate: 2017-10-16T06:06:48.47235-05:0
      DOI: 10.1002/adfm.201703059
       
  • Targeted Delivery of CRISPR/Cas9-Mediated Cancer Gene Therapy via
           Liposome-Templated Hydrogel Nanoparticles
    • Authors: Zeming Chen; Fuyao Liu, Yanke Chen, Jun Liu, Xiaoying Wang, Ann T. Chen, Gang Deng, Hongyi Zhang, Jie Liu, Zhangyong Hong, Jiangbing Zhou
      Abstract: Due to its simplicity, versatility, and high efficiency, the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 technology has emerged as one of the most promising approaches for treatment of a variety of genetic diseases, including human cancers. However, further translation of CRISPR/Cas9 for cancer gene therapy requires development of safe approaches for efficient, highly specific delivery of both Cas9 and single guide RNA to tumors. Here, novel core–shell nanostructure, liposome-templated hydrogel nanoparticles (LHNPs) that are optimized for efficient codelivery of Cas9 protein and nucleic acids is reported. It is demonstrated that, when coupled with the minicircle DNA technology, LHNPs deliver CRISPR/Cas9 with efficiency greater than commercial agent Lipofectamine 2000 in cell culture and can be engineered for targeted inhibition of genes in tumors, including tumors the brain. When CRISPR/Cas9 targeting a model therapeutic gene, polo-like kinase 1 (PLK1), is delivered, LHNPs effectively inhibit tumor growth and improve tumor-bearing mouse survival. The results suggest LHNPs as versatile CRISPR/Cas9-delivery tool that can be adapted for experimentally studying the biology of cancer as well as for clinically translating cancer gene therapy.Clinical translation of CRISPR/Cas9 technology requires development of safe approaches for efficient delivery of Cas9 and guide RNA. Here, novel liposome-templated hydrogel nanoparticles (LHNPs) optimized for codelivery of protein and nucleic acids are reported. It is demonstrated that when coupled with the minicircle technology, LHNPs deliver CRISPR/Cas9 with efficiency adequate for treatment of tumors within and outside of the brain.
      PubDate: 2017-10-16T06:05:36.015445-05:
      DOI: 10.1002/adfm.201703036
       
  • Multimodal Bioactivation of Hydrophilic Electrospun Nanofibers Enables
           Simultaneous Tuning of Cell Adhesivity and Immunomodulatory Effects
    • Authors: Laura Wistlich; Juliane Kums, Angela Rossi, Karl-Heinz Heffels, Harald Wajant, Jürgen Groll
      Abstract: Biomaterials research usually focuses on functional and structural mimicry of the extracellular matrix or tissue hierarchy and morphology. Most recently, material-induced modulatory effects on the immune system to arouse a healing response is another upcoming strategy. Approaches, however, that integrate both aspects to induce healing and facilitate specific cell adhesion are so far little explored. This study exploits manifold but chemical crosslinker free functionalization of hydrophilic and nonadhesive electrospun fiber surfaces with peptides for controlled cell adhesion, and with neutra­lizing antibodies targeting the master cytokine tumor necrosis factor (TNF) to dampen proinflammatory reactions by the fiber adherent cells. It is demonstrated that cell attachment and immunomodulatory properties of a textile can be tailored at the same time to generate meshes that combine immunosuppressive activity with specific cell adhesion properties.A simple, robust strategy for multimodal fiber functionalization within one preparation step using reactive isocyanate macromeres is presented. A threefold functiona­lization and the application of this approach generating meshes with biochemical activity is demonstrated. Immobilization of different antibodies and RGD peptides results in fibers with TNF-depleting and cell binding activity which may be used as immunomodu­latory wound dressings materials.
      PubDate: 2017-10-13T07:15:54.651361-05:
      DOI: 10.1002/adfm.201702903
       
  • Facile Synthesis of Red/NIR AIE Luminogens with Simple Structures, Bright
           Emissions, and High Photostabilities, and Their Applications for Specific
           Imaging of Lipid Droplets and Image-Guided Photodynamic Therapy
    • Authors: Dong Wang; Huifang Su, Ryan T. K. Kwok, Guogang Shan, Anakin C. S. Leung, Michelle M. S. Lee, Herman H. Y. Sung, Ian D. Williams, Jacky W. Y. Lam, Ben Zhong Tang
      Abstract: Red/near-infrared (NIR) fluorescent molecules with aggregation-induced emission (AIE) characteristics are of great interest in bioimaging and therapeutic applications. However, their complicated synthetic approaches remain the major barrier to implementing these applications. Herein, a one-pot synthetic strategy to prepare a series of red/NIR-emissive AIE luminogens (AIEgens) by fine-tuning their molecular structures and substituents is reported. The obtained AIEgens possess simple structures, good solubilities, large Stokes shifts, and bright emissions, which enable their applications toward in vitro and in vivo imaging without any pre-encapsulation or -modification steps. Excellent targeting specificities to lipid droplets (LDs), remarkable photostabilities, high brightness, and low working concentrations in cell imaging application make them remarkably impressive and superior to commercially available LD-specific dyes. Interestingly, these AIEgens can efficiently generate reactive oxygen species upon visible light irradiation, endowing their effective application for photodynamic ablation of cancer cells. This study, thus, not only demonstrates a facile synthesis of red/NIR AIEgens for dual applications in simultaneous imaging and therapy, but also offers an ideal architecture for the construction of AIEgens with long emission wavelengths.A one-pot synthetic strategy is described for preparing red- and near-infrared-emissive aggregation-induced emission (AIE) luminogens (AIEgens) with simple structures, large Stokes shifts, and bright emissions. These AIEgens can be utilized as lipid droplet-specific bioprobes in cell imaging and in vivo zebrafish imaging with high photostabilities and brightness. They are also effective in photodynamic cancer cell ablation upon visible light irradiation.
      PubDate: 2017-10-11T06:48:47.220654-05:
      DOI: 10.1002/adfm.201704039
       
  • Photoactive Hybrid AuNR-Pt@Ag2S Core–Satellite Nanostructures for
           Near-Infrared Quantitive Cell Imaging
    • Authors: Aihua Qu; Liguang Xu, Maozhong Sun, Liqiang Liu, Hua Kuang, Chuanlai Xu
      Abstract: The quantitative detection of microRNA (miR) and multimode-imaging-induced photothermal therapy in vivo have become the focus of much attention. Platinum (Pt) decorated gold nanorods (AuNR-Pt) and Ag2S core–satellite (AuNR-Pt@Ag2S) multifunctional nanostructures are fabricated to quantify intracellular miRs (miR-21), near-infrared fluorescence cell quantitative imaging, and tumor ablation in vivo. When combined with miR-21, the nanoassembly displays significant fluorescence intensity in the second window of the near-infrared region (1000–1700 nm) after 808 nm excitation. The Ag2S fluorescence intensity has a good linear relationship with the amount of intracellular miR in the range of 0.054–20.45 amol ngRNA−1 and a limit of detection of 0.0082 amol ngRNA−1. The nanoassembly is also used to develop multimodal bioimaging, including near-infrared, X-ray computed tomographic, and photoacoustic imaging in HeLa-tumor-bearing mice. Moreover, the tumors are completely eliminated by the high photothermal capacity of the AuNR-Pt@Ag2S assembly. This nanoassembly provides a multifunctional nanoplatform for the ultrasensitive detection of miRs and tumor diagnosis and therapy in vivo.AuNR-Pt@Ag2S multi­functional nanostructures with the yield up to 80% have been fabricated. The Ag2S fluorescent ima­ging in living cells is exhibited to quantify miRNA with a LOD of 0.0082 amol/ngRNA. To be noticed, this is the first reported the Ag2S fluorescent imaging in living cells has been developed.
      PubDate: 2017-10-10T07:12:08.112183-05:
      DOI: 10.1002/adfm.201703408
       
  • Theranostic Prodrug Vesicles for Reactive Oxygen Species-Triggered
           Ultrafast Drug Release and Local-Regional Therapy of Metastatic
           Triple-Negative Breast Cancer
    • Authors: Fangyuan Zhou; Bing Feng, Tingting Wang, Dangge Wang, Zhirui Cui, Siling Wang, Chunyong Ding, Zhiwen Zhang, Jian Liu, Haijun Yu, Yaping Li
      Abstract: A reactive oxygen species (ROS)-activatable doxorubicin (Dox) prodrug vesicle (RADV) is presented for image-guided ultrafast drug release and local-regional therapy of the metastatic triple-negative breast cancer (TNBC). RADV is prepared by integrating a ROS-activatable Dox prodrug, a poly(ethylene glycol) (PEG)-modified photosensitizer pyropheophorbide-a, an unsaturated phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine, and cholesterol into one single nanoplatform. RADV is of extremely high drug loading ratio (27.5 wt%) by self-assembly of the phospholipid-mimic Dox prodrug into the liposomal bilayer membrane. RADV displays good colloidal stability to prevent premature drug leakage during the blood circulation and inert photochemotoxicity to avoid nonspecific side effect. RADV passively accumulates at tumor site through the enhanced permeability and retention effect when administrated systemically. Once deposited at the tumor site, RADV generates fluorescent and photoacoustic signals to guide near-infrared (NIR) laser irradiation, which can induce localized ROS generation, not only to trigger prodrug activation and ultrafast drug release but also conduct photodynamic therapy in a spatiotemporally controlled manner. In combination with NIR laser irradiation, RADV efficiently inhibits the tumor growth and distant metastasis of TNBC. Local-regional tumor therapy using intelligent theranostic nanomedicine might provide an alternative option for highly efficient treatment of the metastatic TNBC.A reactive oxygen species (ROS)-activatable doxorubicin prodrug vesicle (RADV) is reported for image-guided local-regional therapy of triple-negative breast cancer (TNBC). Under the guidance of fluorescence and photoacoustic imaging, NIR laser irradiation is performed to induce ROS generation and trigger drug release at the tumor site. RADV efficiently inhibits TNBC tumor growth and distant metastasis by combing photodynamic and locally activated chemotherapy.
      PubDate: 2017-10-04T02:52:30.940807-05:
      DOI: 10.1002/adfm.201703674
       
  • Sub-Micrometer Structure Formation during Spin Coating Revealed by
           Time-Resolved In Situ Laser and X-Ray Scattering
    • Authors: Jacobus J. van Franeker; Daniel Hermida-Merino, Cedric Gommes, Kirill Arapov, Jasper J. Michels, René A. J. Janssen, Giuseppe Portale
      Abstract: Solution-processed thin polymer films have many applications, such as organic electronics and block-copolymer nanofabrication. These films are often made by spin coating a solution that contains one or more solids and can show different phase-separated structures. The formation mechanism of the droplet-like morphology is studied here by processing polystyrene (PS) and a fullerene derivative ([6,6]-phenyl-C71-butyric acid methyl ester, [70]PCBM) from o-xylene. The final structure consists of [70]PCBM droplets partially embedded in a PS-rich matrix showing interdomain distance of 100–1000 nm as determined from transmission electron microscopy and grazing incidence small angle X-ray scattering (GISAXS). To elucidate the formation of these morphologies in real time, ultrafast in situ GISAXS coupled with laser interferometry and laser scattering is performed during spin coating. In situ thickness measurements and laser scattering show that liquid–liquid phase separation occurs at ≈70 vol% solvent. Subsequently, in only 100–400 ms, almost dry [70]PCBM domains start to protrude from the swollen PS-rich matrix. These results are used to verify the ternary phase diagram calculated using Flory–Huggins theory. The discussed multitechnique approach can be applied to study fundamental aspects in soft matter such as phase separation in thin films occurring at very short time scales.Phase separation in droplet-forming polymer:fullerene mixtures is studied in real time by performing simultaneously in situ X-ray scattering, laser scattering, and thickness measurements. In situ observations combined with ex situ results and data modeling show how droplet formation involves stages like liquid–liquid phase separation and solvent partitioning, resulting in thin films featuring both embedded phase separation and surface topography.
      PubDate: 2017-09-12T07:21:20.335047-05:
      DOI: 10.1002/adfm.201702516
       
 
 
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