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CHEMISTRY (603 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 5)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 25)
ACS Catalysis     Full-text available via subscription   (Followers: 28)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 15)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 21)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 36)
ACS Nano     Full-text available via subscription   (Followers: 178)
ACS Photonics     Full-text available via subscription   (Followers: 7)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 19)
Acta Chemica Iasi     Open Access   (Followers: 1)
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 1)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 6)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 4)
Advanced Functional Materials     Hybrid Journal   (Followers: 44)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 52)
Advances in Chemical Science     Open Access   (Followers: 11)
Advances in Chemistry     Open Access   (Followers: 10)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 15)
Advances in Drug Research     Full-text available via subscription   (Followers: 21)
Advances in Enzyme Research     Open Access   (Followers: 5)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 12)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 16)
Advances in Nanoparticles     Open Access   (Followers: 12)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 14)
Advances in Polymer Science     Hybrid Journal   (Followers: 39)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 16)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 16)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 6)
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)
Alchemy : Jurnal Penelitian 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: 63)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 13)
American Journal of Chemistry     Open Access   (Followers: 23)
American Journal of Plant Physiology     Open Access   (Followers: 12)
American Mineralogist     Full-text available via subscription   (Followers: 8)
Anadolu University Journal of Science and Technology     Open Access  
Analyst     Full-text available via subscription   (Followers: 41)
Angewandte Chemie     Hybrid Journal   (Followers: 135)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 183)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 7)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 10)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Full-text available via subscription  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 5)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 23)
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: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 6)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 8)
Biochemistry     Full-text available via subscription   (Followers: 241)
Biochemistry Insights     Open Access   (Followers: 4)
Biochemistry Research International     Open Access   (Followers: 5)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 3)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access  
Biomacromolecules     Full-text available via subscription   (Followers: 17)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 11)
Biomedical Chromatography     Hybrid Journal   (Followers: 7)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 2)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 110)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 89)
Bioorganic Chemistry     Hybrid Journal   (Followers: 9)
Biopolymers     Hybrid Journal   (Followers: 17)
Biosensors     Open Access   (Followers: 1)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 26)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 2)
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Full-text available via subscription   (Followers: 8)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 27)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 5)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 6)
Cellulose     Hybrid Journal   (Followers: 5)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription  
ChemCatChem     Hybrid Journal   (Followers: 7)
Chemical and Engineering News     Free   (Followers: 10)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 64)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 21)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 18)
Chemical Reviews     Full-text available via subscription   (Followers: 141)
Chemical Science     Open Access   (Followers: 18)
Chemical Technology     Open Access   (Followers: 12)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemical Week     Full-text available via subscription   (Followers: 7)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 53)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 7)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 5)
Chemistry & Biology     Full-text available via subscription   (Followers: 29)
Chemistry & Industry     Hybrid Journal   (Followers: 4)
Chemistry - A European Journal     Hybrid Journal   (Followers: 127)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 14)
Chemistry and Materials Research     Open Access   (Followers: 15)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 4)
Chemistry in Education     Open Access   (Followers: 2)
Chemistry International     Hybrid Journal   (Followers: 1)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 159)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 8)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 6)
ChemPlusChem     Hybrid Journal  
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography Research International     Open Access   (Followers: 5)
Clay Minerals     Full-text available via subscription   (Followers: 8)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 9)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Composite Interfaces     Hybrid Journal   (Followers: 4)
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: 10)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription  
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 2)
CrystEngComm     Full-text available via subscription   (Followers: 9)
Current Catalysis     Hybrid Journal   (Followers: 1)
Current Metabolomics     Hybrid Journal   (Followers: 3)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 7)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 7)
Current Science     Open Access   (Followers: 44)
Dalton Transactions     Full-text available via subscription   (Followers: 17)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 11)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 3)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 2)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 4)
EDUSAINS     Open Access  
Elements     Full-text available via subscription   (Followers: 1)
Environmental Chemistry     Hybrid Journal   (Followers: 5)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 2)

        1 2 3 4 | Last

Journal Cover Advanced Functional Materials
  [SJR: 5.21]   [H-I: 203]   [44 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  [1612 journals]
  • In Vivo Micro-CT Imaging of Human Mesenchymal Stem Cells Labeled with
           Gold-Poly-l-Lysine Nanocomplexes
    • Authors: Taeho Kim; Nohyun Lee, Dian R. Arifin, Irina Shats, Miroslaw Janowski, Piotr Walczak, Taeghwan Hyeon, Jeff W. M. Bulte
      Abstract: Developing in vivo cell tracking is an important prerequisite for further development of cell-based therapy. So far, few computed tomography (CT) cell tracking studies have been described due to its notoriously low sensitivity and lack of efficient labeling protocols. A simple method is presented to render human mesenchymal stem cells (hMSCs) sufficiently radiopaque by complexing 40 nm citrate-stabilized gold nanoparticles (AuNPs) with poly-l-lysine (PLL) and rhodamine B isothiocyanate (RITC). AuNP-PLL-RITC labeling does not affect cellular viability, proliferation, or downstream cell differentiation into adipocytes and osteocytes. Labeled hMSCs can be clearly visualized in vitro and in vivo with a micro-CT scanner, with a detection limit of ≈2 × 104 cells per µL in vivo. Calculated Hounsfield unit values are 2.27 per pg of intracellular Au, as measured with inductively coupled plasma mass spectrophotometry, and are linear over a wide range of cell concentrations. This linear CT attenuation is observed for both naked AuNPs and those that were taken up by hMSCs, indicating that the number of labeled cells can be quantified similar to the use of radioactive or fluorine tracers. This approach for CT cell tracking may find applications in CT image-guided interventions and fluoroscopic procedures commonly used for the injection of cellular therapeutics.AuNP-PLL-RITC nanocomplexes are used to label human mesenchymal stem cells using a simple and straightforward method, allowing cells to be detected in a quantitative manner with an in vivo threshold of ≈2 × 104 cells on micro-CT.
      PubDate: 2016-11-28T08:05:30.330192-05:
      DOI: 10.1002/adfm.201604213
  • Black Gold: Broadband, High Absorption of Visible Light for Photochemical
    • Authors: Charlene Ng; Lim Wei Yap, Ann Roberts, Wenlong Cheng, Daniel E. Gómez
      Abstract: Here, a black Au surface is presented: a material solely composed of Au that is capable of absorbing more than 92% of the incident light over a spectral region ranging from 300 to 600 nm and that can maintain a high absorbance (above 70%) for wavelengths up to 800 nm. The black Au surface is fabricated by a simple and scalable template-assisted physical vapor deposition technique and possesses the flexibility of adhering to any arbitrary substrate. The high absorbance of Au originates from the close packing of high aspect ratio Au nanotubes possessing a random tapered wall thickness. Fabry–Perot resonances of gap-plasmon modes between the Au nanotubes are also responsible for the strong suppression of reflectance of black Au as demonstrated by finite element method simulations. Furthermore, the ability of this surface to drive photochemical transformations under visible light illumination is demonstrated. Hence, black Au could provide a new paradigm for the use of highly absorbing metal nanostructures to effectively harvest the entire visible spectrum for photorelated applications such as solar fuel production, photodetection, and photovoltaics.A novel black gold material that exhibits broadband high absorption of visible light is presented. It consists of closely packed gold nanotubes with tapered wall thickness. The high light-absorbing property can be applied to visible light photochemical systems and function as an efficient photocatalyst over a broad range of wavelengths.
      PubDate: 2016-11-28T08:00:34.188457-05:
      DOI: 10.1002/adfm.201604080
  • Dumbbell Fluidic Tweezers for Dynamical Trapping and Selective Transport
           of Microobjects
    • Authors: Qi Zhou; Tristan Petit, Hongsoo Choi, Bradley J. Nelson, Li Zhang
      Abstract: Mobile microvortices generated by rotating nickel (Ni) nanowires (NW) have been reported as capable of inducing fluidic trapping that can be precisely focused and translated to manipulate microobjects. Here, a new design for significantly enhanced fluidic trapping is reported, which is a dumbbell (DB)-shaped magnetic actuator, assembled by a Ni NW and two polystyrene microbeads. In contrast to the single mode of tumbling trapping possessed by Ni NW, the magnetic dumbbell is able to perform dynamical trapping and implement on-demand transport of microobjects in three modes, i.e., tumbling, wobbling, and rolling. Experiments are conducted to demonstrate the robustness and efficacy of the fluidic trap by the DB actuator. And simulations using a finite element model compare the fluidic traps induced by NW and DB, followed by further discussion on the actuation and transport efficiency of NW and DB fluidic tweezers (FT). At last, some practical issues regarding the application of DB FT are addressed.A dumbbell microactuator consisting of nickel nanowire and polystyrene microbeads is developed as a type of versatile fluidic tweezers to trap and transport individual microobjects. It can generate robust and highly focused microvortices when actuated with a low-strength rotating magnetic field, and is able to manipulate microobjects with high precision via three-modal locomotion, namely, rolling, wobbling, and tumbling.
      PubDate: 2016-11-25T04:31:36.534018-05:
      DOI: 10.1002/adfm.201604571
  • Miniaturized Battery-Free Wireless Systems for Wearable Pulse Oximetry
    • Authors: Jeonghyun Kim; Philipp Gutruf, Antonio M. Chiarelli, Seung Yun Heo, Kyoungyeon Cho, Zhaoqian Xie, Anthony Banks, Seungyoung Han, Kyung-In Jang, Jung Woo Lee, Kyu-Tae Lee, Xue Feng, Yonggang Huang, Monica Fabiani, Gabriele Gratton, Ungyu Paik, John A. Rogers
      Abstract: Development of unconventional technologies for wireless collection and analysis of quantitative, clinically relevant information on physiological status is of growing interest. Soft, biocompatible systems are widely regarded as important because they facilitate mounting on external (e.g., skin) and internal (e.g., heart and brain) surfaces of the body. Ultraminiaturized, lightweight, and battery-free devices have the potential to establish complementary options in biointegration, where chronic interfaces (i.e., months) are possible on hard surfaces such as the fingernails and the teeth, with negligible risk for irritation or discomfort. Here, the authors report materials and device concepts for flexible platforms that incorporate advanced optoelectronic functionality for applications in wireless capture and transmission of photoplethysmograms, including quantitative information on blood oxygenation, heart rate, and heart rate variability. Specifically, reflectance pulse oximetry in conjunction with near-field communication capabilities enables operation in thin, miniaturized flexible devices. Studies of the material aspects associated with the body interface, together with investigations of the radio frequency characteristics, the optoelectronic data acquisition approaches, and the analysis methods capture all of the relevant engineering considerations. Demonstrations of operation on various locations of the body and quantitative comparisons to clinical gold standards establish the versatility and the measurement accuracy of these systems, respectively.Materials and device concepts are introduced for millimeter-scale, battery-free, optoelectronic systems that can capture and wirelessly transmit heart rate and blood oxygenation. Reflectance pulse oximetry and near-field communication capabilities enable operation in thin, miniaturized flexible devices. Demonstrations on various body locations establish the versatility and the measurement accuracy and highlight advantages of signal acquisition due to absence of motion artifacts.
      PubDate: 2016-11-25T04:30:59.592832-05:
      DOI: 10.1002/adfm.201604373
  • General Synthesis of N-Doped Macroporous Graphene-Encapsulated Mesoporous
           Metal Oxides and Their Application as New Anode Materials for Sodium-Ion
           Hybrid Supercapacitors
    • Authors: Min Su Kim; Eunho Lim, Seongbeen Kim, Changshin Jo, Jinyoung Chun, Jinwoo Lee
      Abstract: A general method to synthesize mesoporous metal oxide@N-doped macroporous graphene composite by heat-treatment of electrostatically co-assembled amine-functionalized mesoporous silica/metal oxide composite and graphene oxide, and subsequent silica removal to produce mesoporous metal oxide and N-doped macroporous graphene simultaneously is reported. Four mesoporous metal oxides (WO3−x, Co3O4, Mn2O3, and Fe3O4) are encapsulated in N-doped macroporous graphene. Used as an anode material for sodium-ion hybrid supercapacitors (Na-HSCs), mesoporous reduced tungsten oxide@N-doped macroporous graphene (m-WO3−x@NM-rGO) gives outstanding rate capability and stable cycle life. Ex situ analyses suggest that the electrochemical reaction mechanism of m-WO3−x@NM-rGO is based on Na+ intercalation/de-intercalation. To the best of knowledge, this is the first report on Na+ intercalation/de-intercalation properties of WO3−x and its application to Na-HSCs.N-doped macroporous graphene-encapsulated mesoporous metal oxides for new energy storage systems, namely, sodium-ion hybrid supercapacitors (Na-HSCs), are presented. An Na-HSC system comprising an N-doped macroporous graphene-encapsulated mesoporous tungsten oxide anode and an MSP-20 cathode delivers high energy and power densities, with excellent cycling stability.
      PubDate: 2016-11-25T01:11:18.681078-05:
      DOI: 10.1002/adfm.201603921
  • Size-Scalable and High-Density Liquid-Metal-Based Soft Electronic Passive
           Components and Circuits Using Soft Lithography
    • Authors: Min-gu Kim; Hommood Alrowais, Spyridon Pavlidis, Oliver Brand
      Abstract: The use of conducting liquids with high electrical conductivity, such as eutectic gallium–indium (EGaIn), has great potential in electronics applications requiring stretchability and deformability beyond conventional flexible electronics relying on solid conductors. An advanced liquid metal thin-line patterning process based on soft lithography and a compatible vertical integration technique are presented that enable size-scalable and high-density EGaIn-based, soft microelectronic components and circuits. The advanced liquid metal thin-line patterning process based on poly(dimethylsiloxane) (PDMS) substrates and soft lithography techniques allows for simultaneous patterning of uniform and residue-free EGaIn lines with line width from single micrometers to several millimeters at room temperature and under ambient pressure. Using this fabrication technique, passive electronic components and circuits are investigated under elastic deformations using numerical and experimental approaches. In addition, soft through-PDMS vias with high aspect ratio are demonstrated for multilayer interconnections in 2.5D and 3D integration approaches. To highlight the system-level potential of the patterning technique, a chemical sensor based on an integrated LC resonance circuit with a microfluidic-tunable interdigitated capacitor and a planar spiral inductor is fabricated and characterized. Finally, to show the flexibility and stretchability of the resulting electronics, circuits with embedded light emitting diodes (LEDs) are investigated under bending, twisting, and stretching deformations.An advanced EGaIn thin-line patterning process based on soft lithography and a vertical integration technique are presented that enable size-scalable and high-density eutectic gallium–indium (EGaIn)-based, soft microelectronic components and circuits. The proposed fabrication technique enables size-scalable, high-resolution, uniform, and residue-free EGaIn patterns for passive components and circuits. Also, microfluidic integration for chemical sensing applications and multilayered integration using soft vias are demonstrated.
      PubDate: 2016-11-25T01:11:12.991487-05:
      DOI: 10.1002/adfm.201604466
  • Monomolecular and Bimolecular Recombination of Electron–Hole Pairs at
           the Interface of a Bilayer Organic Solar Cell
    • Authors: Tobias Hahn; Steffen Tscheuschner, Frank-Julian Kahle, Markus Reichenberger, Stavros Athanasopoulos, Christina Saller, Guillermo C. Bazan, Thuc-Quyen Nguyen, Peter Strohriegl, Heinz Bässler, Anna Köhler
      Abstract: While it has been argued that field-dependent geminate pair recombination (GR) is important, this process is often disregarded when analyzing the recombination kinetics in bulk heterojunction organic solar cells (OSCs). To differentiate between the contributions of GR and nongeminate recombination (NGR) the authors study bilayer OSCs using either a PCDTBT-type polymer layer with a thickness from 14 to 66 nm or a 60 nm thick p-DTS(FBTTh2)2 layer as donor material and C60 as acceptor. The authors measure JV-characteristics as a function of intensity and charge-extraction-by-linearly-increasing-voltage-type hole mobilities. The experiments have been complemented by Monte Carlo simulations. The authors find that fill factor (FF) decreases with increasing donor layer thickness (Lp) even at the lowest light intensities where geminate recombination dominates. The authors interpret this in terms of thickness dependent back diffusion of holes toward their siblings at the donor–acceptor interface that are already beyond the Langevin capture sphere rather than to charge accumulation at the donor–acceptor interface. This effect is absent in the p-DTS(FBTTh2)2 diode in which the hole mobility is by two orders of magnitude higher. At higher light intensities, NGR occurs as evidenced by the evolution of s-shape of the JV-curves and the concomitant additional decrease of the FF with increasing layer thickness.Back diffusion of holes is identified to control the fill factor and thus the efficiency of bilayer organic solar cells. The competition between recombination at the donor–acceptor interface and extraction at the electrodes is studied by varying the donor layer thickness and light intensity such as to differentiate between monomolecular, i.e., geminate recombination and bimolecular, nongeminate recombination.
      PubDate: 2016-11-23T07:40:50.341212-05:
      DOI: 10.1002/adfm.201604906
  • Thermal and Electrical Properties of Nanocomposites Based on
           Self-Assembled Pristine Graphene
    • Authors: Jennifer L. Bento; Elizabeth Brown, Steven J. Woltornist, Douglas H. Adamson
      Abstract: Thermodynamically-driven exfoliation and self-assembly of pristine graphene sheets is shown to provide thermally and electrically functional polymer composites. The spreading of graphene sheets at a high energy liquid/liquid interface is driven by lowering the overall energy of the system, and provides for the formation of water-in-oil emulsions stabilized by overlapping graphene sheets. Polymerization of the oil phase, followed by removal of the dispersed water phase, produces inexpensive and porous composite foams. Contact between the graphene-stabilized water droplets provides a pathway for electrical and thermal transport through the composite. Unlike other graphene foams, the graphite used to synthesize these composites is natural flake material, with no oxidation, reduction, sonication, high temperature thermal treatment, addition of surfactants, or high shear mixing required. The result is an inexpensive, low-density material that exhibits Joule heating and displays increasing electrical conductivity with decreasing thermal conductivity.Thermodynamically driven exfoliation and self-assembly of pristine graphene sheets is shown to provide thermally and electrically functional polymer composites. The graphite used to synthesize these composites is natural flake material, with no oxidation, reduction, sonication, addition of surfactants, or high shear mixing required. The result is an inexpensive, low-density material with a production cost expected to be similar to polystyrene foam.
      PubDate: 2016-11-23T05:35:35.852059-05:
      DOI: 10.1002/adfm.201604277
  • A General Solvent Selection Strategy for Solution Processed Quantum Dots
           Targeting High Performance Light-Emitting Diode
    • Authors: Yatao Zou; Muyang Ban, Wei Cui, Qi Huang, Chen Wu, Jiawei Liu, Haihua Wu, Tao Song, Baoquan Sun
      Abstract: An all-solution-processed quantum dots (QDs) light emitting diode (QLED) consists of different layers deposited from various orthogonal solvents. Here, the authors develop a general solvent selection strategy to obtain orthogonal solubility properties as well as high film quality. It is found that a “poor” QDs film morphology with striation defects often occurs when the QDs film is deposited from “bad” solvent. A physical model is presented to rationalize the observed striation defects, and then a general solvent selection strategy is proposed to prevent both surface striation defects and the dissolving of the underlying layers by carefully choosing the “good” solvent for QDs. A compact QDs film can be fabricated without altering the original morphology of underlying functional layers in a QLED device, leading to significant device performance improvement. An external quantum efficiency of 15.45% is achieved in a green QLED with uniform emitting region. This solvent selection strategy provides a general way to deposit high quality films for most of the solution-processed multilayer optoelectronic devices.A general solvent selection strategy for all-solution-processed light-emitting quantum dots is proposed in which a “good” orthogonal solvent for quantum dots should prevent both surface striation defects and the dissolving of the underlying layers. Based on this strategy, an external quantum efficiency of 15.45% is achieved for a quantum dots light-emitting diodes device with uniform green emitting region.
      PubDate: 2016-11-23T05:35:28.415424-05:
      DOI: 10.1002/adfm.201603325
  • “Black” Titania Coatings Composed of Sol–Gel Imprinted
           Mie Resonators Arrays
    • Authors: Thomas Bottein; Thomas Wood, Thomas David, Jean Benoît Claude, Luc Favre, Isabelle Berbézier, Antoine Ronda, Marco Abbarchi, David Grosso
      Abstract: Optical technologies and devices rely on the controlled manipulation of light propagation through a medium. This is generally governed by the inherent effective refractive index of the material as well as by its structure and dimensionality. Although a precise control over light propagation with sub-wavelength size objects is a crucial issue for a plethora of applications, the widely used fabrication methods remain cumbersome and expensive. Here, a sol–gel dip-coating method combined with nanoimprinting lithography on arbitrary glass and silicon substrates is implemented for the fabrication of TiO2-based dielectric Mie resonators. The technique allows obtaining sub-micrometric pillars featuring unprecedented vertical aspect ratios (>1) with relatively high fidelity and precision. Spectroscopic characterization at visible and near-infrared frequencies demonstrate that the resonant properties of these dielectric pillar arrays allow for a drastic reduction of light transmission (cutting more than 50% on glass) and reduced reflection (reflecting less than 3% on glass and 16% on bulk silicon), accounting for an efficient light trapping. These results provide a guideline for the fabrication of Mie resonators using a fast, versatile, low-cost, low-temperature technique for efficient light manipulation at the nanoscale.Titania-based dielectric Mie resonators (MRs) are fabricated via a joint sol–gel dip-coating and soft-nanoimprint lithography method. The coating of SiO2 glass substrates with TiO2 MRs allows for large modifications of light propagation, leading to reduced reflection and transmission owing to an efficient light trapping effect. The same fabrication methodology applied to a silicon substrate produces an efficient broad band antireflection coating.
      PubDate: 2016-11-23T05:30:38.855308-05:
      DOI: 10.1002/adfm.201604924
  • Transition Metal Dichalcogenide-Based Transistor Circuits for Gray Scale
           Organic Light-Emitting Displays
    • Authors: Sanghyuck Yu; Jin Sung Kim, Pyo Jin Jeon, Jongtae Ahn, Jae Chul Park, Seongil Im
      Abstract: Two types of transition metal dichalcogenide (TMD) transistors are applied to demonstrate their possibility as switching/driving elements for the pixel of organic light-emitting diode (OLED) display. Such TMD materials are 6 nm thin WSe2 and MoS2 as a p-type and n-type channel, respectively, and the pixel is thus composed of external green OLED and nanoscale thin channel field effect transistors (FETs) for switching and driving. The maximum mobility of WSe2-FETs either as switch or as driver is ≈30 cm2 V−1 s−1, in linear regime of the gate voltage sweep range. Digital (ON/OFF-switching) and gray-scale analogue operations of OLED pixel are nicely demonstrated. MoS2 nanosheet FET-based pixel is also demonstrated, although limited to alternating gray scale operation of OLED. Device stability issue is still remaining for future study but TMD channel FETs are very promising and novel for their applications to OLED pixel because of their high mobility and ID ON/OFF ratio.2D transition metal dichalcogenides (TMD), WSe2, and MoS2 are used to demonstrate their performances in pixels of organic light-emitting diode (OLED) displays. The pixel is composed of an external green OLED and TMD-channel driving/switching transistors. Digital (ON/OFF-switching) and gray-scale analogue operations of OLED pixels are nicely demonstrated.
      PubDate: 2016-11-23T05:30:27.966343-05:
      DOI: 10.1002/adfm.201603682
  • A Cooperative Copper Metal–Organic Framework-Hydrogel System Improves
           Wound Healing in Diabetes
    • Authors: Jisheng Xiao; Siyu Chen, Ji Yi, Hao F. Zhang, Guillermo A. Ameer
      Abstract: Chronic nonhealing wounds remain a major clinical challenge that would benefit from the development of advanced, regenerative dressings that promote wound closure within a clinically relevant time frame. The use of copper ions has shown promise in wound healing applications, possibly by promoting angiogenesis. However, reported treatments that use copper ions require multiple applications of copper salts or oxides to the wound bed, exposing the patient to potentially toxic levels of copper ions and resulting in variable outcomes. Herein the authors set out to assess whether copper metal organic framework nanoparticles (HKUST-1 NPs) embedded within an antioxidant thermoresponsive citrate-based hydrogel would decrease copper ion toxicity and accelerate wound healing in diabetic mice. HKUST-1 and poly-(polyethyleneglycol citrate-co-N-isopropylacrylamide) (PPCN) are synthesized and characterized. HKUST-1 NP stability in a protein solution with and without embedding them in PPCN hydrogel is determined. Copper ion release, cytotoxicity, apoptosis, and in vitro migration processes are measured. Wound closure rates and wound blood perfusion are assessed in vivo using the splinted excisional dermal wound diabetic mouse model. HKUST-1 NPs disintegrated in protein solution while HKUST-1 NPs embedded in PPCN (H-HKUST-1) are protected from degradation and copper ions are slowly released. Cytotoxicity and apoptosis due to copper ion release are significantly reduced while dermal cell migration in vitro and wound closure rates in vivo are significantly enhanced. In vivo, H-HKUST-1 induced angiogenesis, collagen deposition, and re-epithelialization during wound healing in diabetic mice. These results suggest that a cooperatively stabilized, copper ion-releasing H-HKUST-1 hydrogel is a promising innovative dressing for the treatment of chronic wounds.A copper ion-eluting thermoresponsive antioxidant hydrogel consisting of metal organic framework (HKUST-1) nanoparticles and poly(polyethylene glycol citrate-co-N-isopropylacrylamide) is prepared and characterized (H-HKUST-1). H-HKUST-1 exhibits significantly reduced cytotoxicity and promotes the migration of dermal cells in vitro. In vivo, H-HKUST-1 promotes improved dermal wound closure rates in diabetic mice.
      PubDate: 2016-11-23T02:31:21.401487-05:
      DOI: 10.1002/adfm.201604872
  • Masthead: (Adv. Funct. Mater. 44/2016)
    • PubDate: 2016-11-21T07:56:15.775505-05:
      DOI: 10.1002/adfm.201670289
  • Electrically Controllable Actuators Based on Supramolecular Peptide
    • Authors: Bin Xue; Meng Qin, Tiankuo Wang, Junhua Wu, Dongjun Luo, Qing Jiang, Ying Li, Yi Cao, Wei Wang
      Abstract: Hydrogel actuators that can undergo structural change upon external stimuli are highly demanded due to their potential applications in diverse fields. However, the actuators based on physically cross-linked supramolecular hydrogels are largely unexplored. This study reports the engineering of an electrically controllable supramolecular hydrogel as an actuator from a self-assembling short peptide, in which a catechol moiety is introduced as the stimuli-responsive motif. This kind of electrochemically responsive hydrogel is mechanically stable and can switch its physical properties dramatically upon the applied electric field. The mechanism and reversibility of the change are studied in detail. As a proof of principle, devices are designed to perform the unidirectional expansion and rotational motion under electrical stimulations. The applications of the actuators for controllable drug release and actuation of microfluidic devices are also illustrated. It is expected that these kind of supramolecular hydrogel actuators can find broad applications as novel biosensors, artificial robots, and smart soft materials.Electrically controllable hydrogels have been used as biomimetic actuators in diverse fields. However, these hydrogels are mainly made of ionic polymers and the supramolecular hydrogels for actuators are yet to be demonstrated. Here this study shows the possibility of using redox responsive peptide hydrogels as electrically sensitive units for various actuators. The applications of the actuators are also illustrated.
      PubDate: 2016-11-18T15:01:24.709914-05:
      DOI: 10.1002/adfm.201603947
  • Organic–Inorganic Hierarchical Self-Assembly into Robust Luminescent
           Supramolecular Hydrogel
    • Authors: Zhiqiang Li; Zhaohui Hou, Hongxian Fan, Huanrong Li
      Abstract: Luminescent hydrogels are of great potential for many fields, particularly serving as biomaterials ranging from fluorescent sensors to bioimaging agents. Here, robust luminescent hydrogels are reported using lanthanide complexes as emitting sources via a hierarchical organic–inorganic self-assembling strategy. A new organic ligand is synthesized, consisting of a terpyridine unit and two flexibly linked methylimidazole moieties to coordinate with europium(III) (Eu3+) tri-thenoyltrifluoroacetone (Eu(TTA)3), leading to a stable amphiphilic Eu3+-containing monomer. Synergistic coordination of TTA and terpyridine units allows the monomer to self-assemble into spherical micelles in water, thus maintaining the luminescence of Ln complexes in water. The micelles further coassemble with exfoliated Laponite nanosheets coated with sodium polyacrylate into networks based on the electrostatic interactions, resulting in the supramolecular hydrogel possessing strong luminescence, extraordinary mechanical property, as well as self-healing ability. The results demonstrate that hierarchical organic–inorganic self-assembly is a versatile and effective strategy to create luminescent hydrogels containing lanthanide complexes, giving rise to great potential applications as a soft material.A luminescent supramolecular hydrogel using lanthanide complexes as emitting sources is constructed via a hierarchical organic–inorganic self-assembling strategy, showing ultrastrong mechanical performance and extraordinary photophysical property.
      PubDate: 2016-11-18T02:25:45.955807-05:
      DOI: 10.1002/adfm.201604379
  • The Roadmap of Graphene-Based Optical Biochemical Sensors
    • Authors: Bannur Nanjunda Shivananju; Wenzhi Yu, Yan Liu, Yupeng Zhang, Bo Lin, Shaojuan Li, Qiaoliang Bao
      Abstract: Graphene is a novel two-dimensional material composed of a one-atom-thick planar sheet of sp2-bonded carbon atoms perfectly arranged in a honeycomb lattice that has exceptional photonic and electronic properties. We believe that the true potential of graphene lies in optical sensors, especially for biochemical sensing in the diagnostics and health care sector. Graphene has extraordinary properties, such as a one-atom thickness, extremely high surface-to-volume ratio, large surface area, ability to quench fluorescence, excellent biocompatibility, broadband light absorption, ultrafast response time, high mechanical strength, outstanding robustness, and flexibility. The working principle is based on whenever the biomolecules come into contact with graphene, the Fermi level shifts to either p-type or n-type, changing the opto-electronic properties. The most important factors in graphene-based optical sensing are lowering the limit of detection and increasing the specificity of label-free biochemical sensing. This article comprehensively and critically reviews emerging graphene optical biochemical sensors. We first elaborate on their opto-electronic properties, fabrication, numerical modeling and simulation, and then review various sensing applications, such as single-cell detection, neural imaging and optogenetics, colorimetric multifunctional sensors, cancer diagnosis, protein and DNA sensing, and gas sensing. Finally, the roadmap of current and future trends in graphene-based optical biochemical sensors is discussed.Graphene-based optical biochemical sensors are capable of lowering the limit of detection and increasing the specificity of label-free biochemical sensing. The working principle is based on whenever biomolecules come into contact with graphene, the Fermi level will shift either to p-type or n-type, changing its opto-electronic properties. This article comprehensively and critically reviews the emerging graphene optical biochemical sensors.
      PubDate: 2016-11-17T08:10:51.654958-05:
      DOI: 10.1002/adfm.201603918
  • Synergistic Effect of Hybrid PbS Quantum Dots/2D-WSe2 Toward High
           Performance and Broadband Phototransistors
    • Authors: Chao Hu; Dongdong Dong, Xiaokun Yang, Keke Qiao, Dun Yang, Hui Deng, Shengjie Yuan, Jahangeer Khan, Yang Lan, Haisheng Song, Jiang Tang
      Abstract: The transitionmetal dichalcogenides-based phototransistors have demonstrated high transport mobility but are limited to poor photoresponse, which greatly blocks their applications in optoelectronic fields. Here, light sensitive PbS colloidal quantum dots (QDs) combined with 2D WSe2 to develop hybrid QDs/2D-WSe2 phototransistors for high performance and broadband photodetection are utilized. The device shows a responsivity up to 2 × 105 A W–1, which is orders of magnitude higher than the counterpart of individual material-based devices. The detection spectra of hybrid devices can be extended to near infrared similar to QDs' response. The high performance of hybrid 0D-2D phototransistor is ascribed to the synergistic function of photogating effect. PbS QDs can efficiently absorb the input illumination and 2D WSe2 supports a transport expressway for injected photocarriers. The hybrid phototransistors obtain a specific detectivity over 1013 Jones in both ON and OFF state in contrast to the depleted working state (OFF) for other reported QDs/2D phototransistors. The present device construction strategy, photogating enhanced performance, and robust device working conditions contain high potential for future optoelectronic devices.High performance hybrid phototransistors for broadband detection based on PbS QDs and 2D WSe2 monolayer are demonstrated. Owing to the synergistic effect of high mobility of WSe2 nanosheet and strong light absorption of PbS QD layer, high responsivity of up to 105 A W–1 is achieved. Further study unfolds the main mechanism, which is attributed to the photogating effect.
      PubDate: 2016-11-16T08:46:32.154799-05:
      DOI: 10.1002/adfm.201603605
  • Flexible, Graphene-Coated Biocomposite for Highly Sensitive, Real-Time
           Molecular Detection
    • Authors: Lili Wang; Joshua A. Jackman, Wei Beng Ng, Nam-Joon Cho
      Abstract: Wearable biosensors hold significant potential for healthcare and environmental applications, and the development of flexible and biocompatible sensing platforms for high accuracy detection of physiological biomarkers remains an elusive goal. Herein, an ultrasensitive, flexible sensor is described that is based on a 3D hierarchical biocomposite comprised of hollow, natural pollen microcapsules that are coated with a conductive graphene layer. Modular assembly of the graphene-coated microcapsules onto an ultrathin polyethylene terephthalate layer enables a highly flexible sensor configuration with tunable selectivity afforded by subsequent covalent immobilization of antibodies against target antigens. In a proof-of-concept example, the biosensor demonstrates ultrahigh sensitivity detection of prostate specific antigen (PSA) down to 1.7 × 10−15m with real-time feedback and superior performance over conventional 2D graphene-coated sensors. Importantly, the device performance is consistently high across various bending conditions. Taken together, the results demonstrated in this work highlight the merits of employing lightweight biocomposites as modular building blocks for the design of flexible biosensors with highly responsive and sensitive molecular detection capabilities.A flexible sensing platform based on a graphene-coated biocomposite exhibits a rapid response (4 s) and ultralow limit of detection (1.7 × 10−15m) against prostate specific antigen (PSA) and superior performance over flat graphene-coated sensors. Importantly, the device performance is high across various bending conditions, highlighting the potential of employing biomaterials as design components in flexible and wearable sensors.
      PubDate: 2016-11-15T09:29:39.62586-05:0
      DOI: 10.1002/adfm.201603550
  • Chiroptical Resolution and Thermal Switching of Chirality in Conjugated
           Polymer Luminescence via Selective Reflection using a Double-Layered Cell
           of Chiral Nematic Liquid Crystal
    • Authors: Jialin Yan; Fuyuki Ota, Benedict A. San Jose, Kazuo Akagi
      Abstract: An optically resolvable and thermally chiral-switchable device for circularly polarized luminescence (CPL) is first constructed using a light-emitting conjugated polymer film and a double-layered chiral nematic liquid crystal (N*-LC) cell. The double-layered N*-LC cell with opposite handedness at each layer is fabricated by adding each of two types of N*-LCs into each of the cells, and the N*-LCs consist of nematic LCs and chiral dopants with opposite chirality and different mole concentrations. The selective reflection band due to the N*-LC is thermally shifted so that the band wavelength is close to the luminescence band of the racemic conjugated polymer, such as disubstituted polyacetylene (diPA), yielding CPL with opposite handedness and high dissymmetry factor values ( glum ) of 1.1–1.6 at low and high temperatures. The double-layered N*-LC cell bearing the temperature-controlled selective reflection is useful for generating CPLs from racemic fluorescent materials and for allowing thermal chirality-switching in CPLs, which present new possibilities for optoelectronic and photochemical applications.An optically resolvable and thermally chiral-switchable device for circularly polarized luminescence (CPL) is constructed using a light-emitting conjugated polymer film and a double-layered cell of chiral nematic liquid crystal (N*-LC) with opposite handedness at each layer. The chirality switching of the CPL is achieved via selective reflections of the N*-LCs with different helical senses.
      PubDate: 2016-11-15T08:04:06.793645-05:
      DOI: 10.1002/adfm.201604529
  • Materials and Device Designs for an Epidermal UV Colorimetric Dosimeter
           with Near Field Communication Capabilities
    • Authors: Hitoshi Araki; Jeonghyun Kim, Shaoning Zhang, Anthony Banks, Kaitlyn E. Crawford, Xing Sheng, Philipp Gutruf, Yunzhou Shi, Rafal M. Pielak, John A. Rogers
      Abstract: Ultraviolet (UV) solar radiation is a leading cause of skin disease. Quantitative, continuous knowledge of exposure levels can enhance awareness and lead to improved health outcomes. Devices that offer this type of measurement capability in formats that can seamlessly integrate with the skin are therefore of interest. This paper introduces materials, device designs, and data acquisition methods for a skin-like, or “epidermal,” system that combines colorimetric and electronic function for precise dosimetry in the UV-A and UV-B regions of the spectrum, and for determination of instantaneous UV exposure levels and skin temperature. The colorimetric chemistry uses (4-phenoxyphenyl)diphenylsulfonium triflate (PPDPS-TF) with crystal violet lactone (CVL) and Congo red for UV-A and UV-B operation, respectively, when integrated with suitable optical filters. Coatings of poly(ethylene-vinylacetate) (PEVA) protect the functional materials from sunscreen and other contamination. Quantitative information follows from automated L*a*b* color space analysis of digital images of the devices to provide accurate measurements when calibrated against standard nonwearable sensors. Techniques of screen printing and lamination allow aesthetic designs and integration with epidermal near field communication platforms, respectively. The result is a set of attractive technologies for managing UV exposure at a personal level and on targeted regions of the body.This paper introduces materials, device designs, and data acquisition methods for a skin-like, or “epidermal,” system that combines colorimetric and wireless electronic function for precise dosimetry in the UV-A and UV-B regions, and for the determination of instantaneous UV exposure levels and skin temperature. Quantitative information follows from automated color analysis of digital images, as validated against digital measurement systems.
      PubDate: 2016-11-15T07:58:47.028607-05:
      DOI: 10.1002/adfm.201604465
  • Photopatterned Multidimensional Fluorescent Images
    • Authors: Peter R. Christensen; Michael O. Wolf
      Abstract: New methods that yield covert fluorescent images are of significant interest for applications in anti-counterfeit technology. Printing methods that offer access to spatially controlled fluorescence intensity are needed in order to accurately reproduce unique and complex images. Herein, the use of photoreactive inks containing 9,9′-bis(anthracene)sulfoxide (AnSO) to create complex images with spatially controlled fluorescence intensity is presented. Under UV irradiation, the SO-bridge between anthracene units in AnSO is extruded to yield the highly luminescent molecule 9,9′-bianthryl (BA) in quantitative yields. The irreversible formation of BA is leveraged to create multidimensional fluorescent security features that can be patterned using light and easily interpreted using the CCD camera of a mobile phone.Inks containing 9,9′-bis(anthracene)sulfoxide (AnSO) are deposited and photopatterned to create multidimensional photoluminescent barcodes and images. Spatially controlled fluorescence intensity is achieved, allowing complex images to be patterned. Simple ink formulations containing AnSO are used to generate covert 3D barcodes for anti-counterfeit applications, which can be easily read using mobile phones.
      PubDate: 2016-11-11T08:55:32.533486-05:
      DOI: 10.1002/adfm.201603294
  • Production of Flexible Transparent Conducting Films of Self-Fused
           Nanowires via One-Step Supersonic Spraying
    • Authors: Jong-Gun Lee; Do-Yeon Kim, Jong-Hyuk Lee, Suman Sinha-Ray, Alexander L. Yarin, Mark T. Swihart, Donghwan Kim, Sam S. Yoon
      Abstract: Scalable and economical manufacturing of flexible transparent conducting films (TCF) is a key barrier to widespread adoption of low-cost flexible electronics. Here, a simple, robust, and scalable method of flexible TCF formation using supersonic kinetic spraying is demonstrated. Silver nanowire (AgNW) suspensions are sprayed at supersonic speed to produce self-sintered films of AgNWs on flexible substrates. These films display remarkably low sheet resistance, 90%. These electrically conducting, transparent, and flexible coatings can be deposited over a 100 cm2 area in ≈30 s. Theoretical analysis reveals the underlying physical mechanism behind self-sintering, showing that self-sintering is enabled by the high velocity of impact in supersonic spraying.A schematic of supersonic spraying of a silver nanowire (AgNW) film is shown. AgNWs are shown in an optical microscope image. Superdeposited nanowires with a junction are highlighted as a scanning electron microscopy (SEM) image.
      PubDate: 2016-11-11T05:06:06.423952-05:
      DOI: 10.1002/adfm.201602548
  • Electron Spin Dynamics of Two-Dimensional Layered Materials
    • Authors: Bálint Náfrádi; Mohammad Choucair, László Forró
      Abstract: The growing library of two-dimensional layered materials is providing researchers with a wealth of opportunity to explore and tune physical phenomena at the nanoscale. Here, we review the experimental and theoretical state-of-art concerning the electron spin dynamics in graphene, silicene, phosphorene, transition metal dichalcogenides, covalent heterostructures of organic molecules and topological materials. The spin transport, chemical and defect induced magnetic moments, and the effect of spin-orbit coupling and spin relaxation, are also discussed in relation to the field of spintronics.The growing library of two-dimensional layered materials is providing researchers with a wealth of opportunity to explore and tune physical phenomena at the nanoscale. Here, the experimental and theoretical state-of-art concerning the electron spin dynamics in graphene, silicene, phosphorene, transition metal dichalcogenides, covalent heterostructures of organic molecules and topological materials in relation to the field of spintronics is reviewed.
      PubDate: 2016-11-11T05:00:43.21117-05:0
      DOI: 10.1002/adfm.201604040
  • Piezoelectric Nylon-11 Nanowire Arrays Grown by Template Wetting for
           Vibrational Energy Harvesting Applications
    • Authors: Anuja Datta; Yeon Sik Choi, Evie Chalmers, Canlin Ou, Sohini Kar-Narayan
      Abstract: Piezoelectric polymers, capable of converting mechanical vibrations into electrical energy, are attractive for use in vibrational energy harvesting due to their flexibility, robustness, ease, and low cost of fabrication. In particular, piezoelectric polymers nanostructures have been found to exhibit higher crystallinity, higher piezoelectric coefficients, and “self-poling,” as compared to films or bulk. The research in this area has been mainly dominated by polyvinylidene fluoride and its copolymers, which while promising have a limited temperature range of operation due to their low Curie and/or melting temperatures. Here, the authors report the fabrication and properties of vertically aligned and “self-poled” piezoelectric Nylon-11 nanowires with a melting temperature of ≈200 °C, grown by a facile and scalable capillary wetting technique. It is shown that a simple nanogenerator comprising as-grown Nylon-11 nanowires, embedded in an anodized aluminium oxide (AAO) template, can produce an open-circuit voltage of 1 V and short-circuit current of 100 nA, when subjected to small-amplitude, low-frequency vibrations. Importantly, the resulting nanogenerator is shown to exhibit excellent fatigue performance and high temperature stability. The work thus offers the possibility of exploiting a previously unexplored low-cost piezoelectric polymer for nanowire-based energy harvesting, particularly at temperatures well above room temperature.Vertically aligned arrays of piezoelectric Nylon-11 nanowires with high aspect ratio are prepared using a capillary template wetting method within nanoporous anodized alumina templates. The template-grown nanowires are “self-poled” and thus can be directly incorporated into nanogenerators with excellent fatigue performance. The relatively high melting temperature (≈200 °C) of these nanowires makes them suitable for energy harvesting applications at elevated temperatures.
      PubDate: 2016-11-11T04:55:59.86763-05:0
      DOI: 10.1002/adfm.201604262
  • Controlled Crystallization of Conjugated Polymer Films from Solution and
           Solvent Vapor for Polymer Electronics
    • Authors: Gisela L. Schulz; Sabine Ludwigs
      Abstract: Over the years, solution-processable conjugated oligomers and polymers have proven to be very promising for application in organic electronic devices. In addition to tuning the chemical structure of the materials, the role of morphology has been identified as a key parameter in determining device performance. Conjugated polymers are typically semicrystalline in nature consisting of both crystalline and amorphous domains giving rise to a wealth of superstructures. In comparison to classical non-conjugated semicrystalline polymers, they bear the additional advantage of absorbing light. This makes UV-vis absorption spectroscopy an excellent tool to monitor polymer aggregation and crystallization in-situ both in solution and in films. With this feature article we point out the delicate interplay between solution processing and the obtained morphology in polythiophenes and low bandgap copolymers. Subtle changes in the preparation protocol lead to significant changes in textures and also give rise to polymorphism. Solvent vapor annealing and solution crystallization are highlighted as tools to control the nucleation and growth processes in semicrystalline polymer films. Structure-function relationships between morphological, optical and electronic properties are demonstrated.Spherulitic superstructures are obtained via controlled nucleation and growth processes in conjugated polymer films, as evidenced by in-situ monitoring of optical absorption. Pre-aggregation in solution and solvent vapor annealing are discussed as excellent methods to reduce nucleation densities and to tune textures and polymorphism.
      PubDate: 2016-11-11T02:41:22.01584-05:0
      DOI: 10.1002/adfm.201603083
  • Molecular Engineering of Highly Efficient Small Molecule Nonfullerene
           Acceptor for Organic Solar Cells
    • Authors: Suman; Vinay Gupta, Anirban Bagui, Surya Prakash Singh
      Abstract: A new molecularly engineered nonfullerene acceptor, 2,2′-(5,5′-(9,9-didecyl-9H-fluorene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl)bis(methanylylidene))bis(3-hexyl-1,4-oxothiazolidine-5,2-diylidene))dimalononitrile (BAF-4CN), with fluorene as the core and arms of dicyano-n-hexylrhodanine terminated benzothiadiazole is synthesized and used as an electron acceptor in bulk heterojunction organic solar cells. BAF-4CN shows a stronger and broader absorption with a high molar extinction coefficient of 7.8 × 104m−1 cm−1 at the peak position (498 nm). In the thin film, the molecule shows a redshift around 17 nm. The photoluminescence experiments confirm the excellent electron accepting nature of BAF-4CN with a Stern–Volmer coefficient (Ksv) of 1.1 × 105m−1. From the electrochemical studies, the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of BAF-4CN are estimated to be −5.71 and −3.55 eV, respectively, which is in good synchronization with low bandgap polymer donors. Using BAF-4CN as an electron acceptor in a poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3″′-di(2-octyldodecyl) 2,2′;5′,2″;5″,2″′-quaterthiophen-5,5″′-diyl)] based bulk-heterojunction solar cell, a maximum power conversion efficiency of 8.4% with short-circuit current values of 15.52 mA cm−2, a fill factor of 70.7%, and external quantum efficiency of about 84% covering a broad range of wavelength is achieved.The non-fullerene acceptor (NFA) BAF-4CN is synthesized for organic photovoltaic (OPV) application to overcome the drawbacks of fullerene. BAF-4CN shows stronger absorption compared to phenyl C71-butyric acid methyl ester and has an excellent electron accepting nature and high charge carrier mobility. A power conversion efficiency of 8.4% is achieved from PffBT4T-2OD:BAF-4CN based bulk heterojunction solar cells. This may be a promising substitute for fullerene in low-cost solution-processed OPV.
      PubDate: 2016-11-10T08:55:58.357462-05:
      DOI: 10.1002/adfm.201603820
  • An Effective Approach for High-Efficiency Photoelectrochemical Solar Cells
           by Using Bifunctional DNA Molecules Modified Photoanode
    • Authors: Özlem Ateş Sönmezoğlu; Seçkin Akın, Begüm Terzi, Serdal Mutlu, Savaş Sönmezoğlu
      Abstract: This paper firstly reports the effect of deoxyribonucleic acid (DNA) molecules extracted from chickpea and wheat plants on the injection/recombination of photogenerated electrons and sensitizing ability of dye-sensitized solar cells (DSSCs). These high-yield DNA molecules are applied as both linker bridging unit as well as thin tunneling barrier (TTB) at titanium dioxide (TiO2 )/dye interface, to build up high-efficient DSSCs. With its favorable energy levels, effective linker bridging role, and double helix structure, bifunctional DNA modifier shows an efficient electron injection, suppressed charge recombination, longer electron lifetime, and higher light harvesting efficiency, which leads to higher photovoltaic performance. In particular, a photoconversion efficiency (PCE) of 9.23% is achieved by the binary chickpea and wheat DNA-modified TiO2 (CW@TiO2) photoanode. Furthermore, time-resolved fluorescence spectroscopy measurements confirm a better electron transfer kinetics for DNA-modified TiO2 photoanodes, implying a higher electron transfer rate (kET). This work highlights a great contribution for the photoanodes that are linked with DNA molecule, which act as both bridging unit and TTB to control the charge recombination and injection dynamics, and hence, boost the photovoltaic performance in the DSSCs.Two types of deoxyribonucleic acid molecules, extracted from fresh leaves of chickpea and wheat plants, employ as thin tunneling barrier at TiO2/dye interface to minimize the recombination rates as well as linker bridging units for the electrons to move toward the TiO2, thereby enhancing Voc and Jsc. This strategy might open up new opportunities for the widespread fabrication and application of dye-sensitized solar cells.
      PubDate: 2016-11-09T16:00:02.915614-05:
      DOI: 10.1002/adfm.201603454
  • One-Pot Synthesis of Freestanding Porous Palladium Nanosheets as Highly
           Efficient Electrocatalysts for Formic Acid Oxidation
    • Authors: Xiaoyu Qiu; Hanyue Zhang, Peishan Wu, Fengqi Zhang, Shaohua Wei, Dongmei Sun, Lin Xu, Yawen Tang
      Abstract: Freestanding ultrathin 2D noble metal nanosheets have drawn enormous attention due to their potential applications in various fields. However, the synthesis of 2D noble metal nanosheets still remains a great challenge due to the lack of an intrinsic driving force for anisotropic growth of 2D structures. Here, a facile one-pot synthesis of ultrathin freestanding porous Pd nanosheets (≈2.5 µm in lateral size and 10 nm in thickness) flexibly knitted by interweaved ultrathin nanowires with the assistance of poly(diallyldimethylammonium chloride) is presented. Nanoparticles attachment and subsequent self-assembly in the synthetic process are responsible for the formation of such intriguing nanostructures. Moreover, finely controlling the pH value of the precursor solution leads to yield different Pd nanostructures with tunable dimensionalities, including 3D nanoflowers, 2D nanosheets, and 1D nanochains. Owing to the unique structural features, the obtained freestanding porous Pd nanosheets exhibit excellent electrocatalytic activity and stability towards formic acid oxidation compared to those of other dimensional counterparts and commercial Pd black.A facile one-pot synthesis of ultrathin freestanding porous Pd nanosheets flexibly knitted by interweaved ultrathin nanowires is presented here. Owing to the unique structural features, the porous Pd nanosheets exhibit excellent electrocatalytic activity and stability towards formic acid oxidation.
      PubDate: 2016-11-09T15:58:34.548865-05:
      DOI: 10.1002/adfm.201603852
  • Peptide-Enhanced Selective Surface Deposition of Polymer-Based Fragrance
           Delivery Systems
    • Authors: Kemal Arda Günay; Daniel Benczédi, Andreas Herrmann, Harm-Anton Klok
      Abstract: Surface deposition is a critical step in the application of fragrance-containing products. This contribution presents a novel strategy to enhance the deposition of polymer-based fragrance delivery systems onto cotton substrates from the application medium using phage display identified peptides. Following the identification of cotton binding peptide ligands under fabric softening conditions via phage display, the strongest binding peptide ligand is incorporated into two model polymer-based fragrance delivery systems, viz., polymer profragrances and polymer nanoparticles. The model polymer profragrance used is a linear, water soluble poly(N-(2-hydroxypropyl)methacrylamide) conjugate, while poly(styrene-co-acrylic acid) (PS-co-PAA) nanoparticles prepared via miniemulsion polymerization are chosen as the second model system. The incorporation of the cotton binding peptide ligand into these fragrance delivery systems enhances their surface deposition two- to three-fold, as evidenced by fluorescence intensity measurements. In the case of the fragrance-containing PS-co-PAA nanoparticles, the enhanced surface deposition also translates into an increased fragrance release from the cotton surface according to dynamic headspace sampling measurements.Surface deposition is an essential step in the application of fragrance-containing products. In this work, a peptide that binds to cotton fabric under softening conditions is identified and used to enhance surface deposition of two polymer-based fragrance delivery systems. This strategy may be generalized to other delivery systems and used for a range of personal care and consumer products.
      PubDate: 2016-11-08T08:30:33.151767-05:
      DOI: 10.1002/adfm.201603843
  • Photodetectors Based on Two-Dimensional Layered Materials Beyond Graphene
    • Authors: Chao Xie; Chunhin Mak, Xiaoming Tao, Feng Yan
      Abstract: Following a significant number of graphene studies, other two-dimensional (2D) layered materials have attracted more and more interest for their unique structures and distinct physical properties, which has opened a window for realizing novel electronic or optoelectronic devices. Here, we present a comprehensive review on the applications of 2D-layered semiconductors as photodetectors, including photoconductors, phototransistors, and photodiodes, reported in the past five years. The device designs, mechanisms, and performances of the photodetectors are introduced and discussed systematically. Emerging techniques to improve device performances by enhancing light-matter interactions are addressed as well. Finally, we deliver a summary and outlook to provide a guideline of the future development of this rapidly growing field.2D layered semiconductors beyond graphene are successfully used in various high-performance photodetectors, including photoconductors, phototransistors, and photodiodes. Here, a comprehensive review on the emerging 2D photodetectors is presented, focusing on the device designs, mechanisms, and performances. Various approaches for the optimization of device performance are introduced. In the end, a summary and an outlook of this field are delivered.
      PubDate: 2016-11-08T08:25:51.004739-05:
      DOI: 10.1002/adfm.201603886
  • Tunable Optical Modulator by Coupling a Triboelectric Nanogenerator and a
           Dielectric Elastomer
    • Authors: Xiangyu Chen; Xiong Pu, Tao Jiang, Aifang Yu, Liang Xu, Zhong Lin Wang
      Abstract: A conjunction system based on triboelectric nanogenerator (TENG) and dielectric elastomer actuator (DEA) is a promising demonstration for the application of TENG in the field of electronic skin and soft robotics. In this paper, a triboelectric tunable smart optical modulator (SOM) has been proposed based on this TENG-DEA system. The SOM has a very simple structure of an elastomer film and electrodes made of dispersed silver nanowires. Owing to the voltage induced rippling of the elastomer, the output of the TENG for a contact-separation motion at a velocity ranging from 0.5 to 10 cm s−1 can decrease the SOM's transmittance from 72% to 40%, which is enough for realizing the function of privacy protection. Meanwhile, an effective operation method is also proposed for this SOM. By serially connecting an accessory DEA to the SOM, an external bias voltage can be applied on the SOM to tune its “threshold” voltage and the output from TENG can smoothly regulate the transmittance on the basis of the bias. The proposed operation method has excellent applicability for all DEA-based devices, which can promote the practical study of TENG-DEA system in the field of micro-electro-mechanical system and human–robots interaction.A triboelectric tunable smart optical modulator (SOM) has been proposed based on this triboelectric nanogenerator (TENG) and dielectric elastomer actuator system. Owing to the voltage-induced rippling of the elastomer, the output of the TENG for a contact-separation motion at a velocity ranging from 0.5 to 10 cm s−1 can decrease the SOM's transmittance from 72% to 40%.
      PubDate: 2016-11-07T08:21:31.869923-05:
      DOI: 10.1002/adfm.201603788
  • Advanced Functional Nanomaterials for Theranostics
    • Authors: Haoyuan Huang; Jonathan F. Lovell
      Abstract: Nanoscale materials have been explored extensively as agents for therapeutic and diagnostic (i.e., theranostic) applications. Research efforts have shifted from exploring new materials in vitro to designing materials that function in more relevant animal disease models, thereby increasing potential for clinical translation. Current interests include non-invasive imaging of diseases, biomarkers, and targeted delivery of therapeutic drugs. Here, some general design considerations of advanced theranostic materials and challenges of their use, from both diagnostic and therapeutic perspectives, are discussed. Common classes of nanoscale biomaterials, including magnetic nanoparticles, quantum dots, upconversion nanoparticles, mesoporous silica nanoparticles, carbon-based nanoparticles, and organic dye-based nanoparticles, have demonstrated potential for both diagnosis and therapy. Variations such as size control and surface modifications can modulate biocompatibility and interactions with target tissues. The need for improved disease detection and enhanced chemotherapeutic treatments, together with realistic considerations for clinically translatable nanomaterials, will be key driving factors for theranostic agent research in the near future.Theranostic nanoparticles have emerged as promising materials that possess both diagnostic and therapeutic functional capabilities as versatile platform technologies. Recent approaches and common classes of materials are reviewed here.
      PubDate: 2016-11-07T08:21:24.813319-05:
      DOI: 10.1002/adfm.201603524
  • Design of Lanthanide-Based OLEDs with Remarkable Circularly Polarized
    • Authors: Francesco Zinna; Mariacecilia Pasini, Francesco Galeotti, Chiara Botta, Lorenzo Di Bari, Umberto Giovanella
      Abstract: Organic light-emitting diodes (OLEDs) able to directly emit circularly polarized (CP) electroluminescence (CP-OLEDs) are rapidly gaining much interest, due to their possible applications in displays with antiglare filters and 3D displays. Development of more efficient CP-OLEDs can open their use also in point-of-care and personalized diagnostic tools, since CP light alteration can be related to health state of irradiated tissues. In this work it is shown that the performance of chiral europium complex-based CP-OLEDs can be improved both in terms of external quantum efficiency (measured on all the Eu bands) and degree of polarization of emitted photons (as measured by the dissymmetry factor gEL), by proper active layer formulation and through a fine tuning of the architecture of the device. Polarization performances (gEL = −1) are obtained about three times higher than for any other CP-OLED reported so far. Moreover, for the first time, it is shown that the position of the recombination zone (RZ) plays a major role on the polarization outcomes. In order to rationalize these results the level of light polarization is related to the position of the RZ allied with the reflection on the cathode through a simple mathematical model. The values predicted by this model are in qualitative agreement with the experimental ones.Lanthanide-based organic light-emitting diodes (OLEDs) with remarkable circularly polarized electroluminescence are designed. 75% of the emitted photons at 595 nm are circularly polarized with enhanced external quantum efficiency with respect to our earlier proof-of-concept achievement. For the first time the main factors affecting circularly polarized OLEDs performance are identified by combining experimental data and modeling to bring the technology to the next readiness level.
      PubDate: 2016-11-03T08:36:06.896953-05:
      DOI: 10.1002/adfm.201603719
  • Versatile Thermochromic Supramolecular Materials Based on Competing Charge
           Transfer Interactions
    • Authors: Tianyu Yuan; Mariela Vazquez, Amanda N. Goldner, Yan Xu, Rafael Contrucci, Millicent A. Firestone, Mark A. Olson, Lei Fang
      Abstract: Stimuli-responsive supramolecular materials are of paramount importance for a broad range of applications. It is essential to impart versatility, sustainability, and scalability into these materials. Herein the authors report the design and synthesis of a new class of thermochromic supramolecular materials, which can easily be processed from water via a reversible sol–gel transition. The supramolecular materials are composed of a bis-bipyridinium acceptor, a π-electron-rich naphthalene derivative donor, and halogen counterions. Long helical nanofibers can be assembled in water, gelating at room temperature. Inked designs, thin films, and aerogels are solution-processed to exhibit thermochromic behavior based on competing π π* and n π* charge transfer interactions. By using different π-electron rich donors, and counterions, the authors demonstrate that both the color observed at room temperature and at high temperatures can be tailored. The results open up the door to develop novel amphiphile-based thermochromes with water processability and a large tunable color palette.A new class of water-processable thermochromic supramolecular materials has been developed. Inked designs, thin films, and aerogels fabricated from these composites exhibit reversible thermochromic behavior. The thermochromism is a result of competing π π* and n π* charge transfer interactions allowing for the color observed at room temperature and at high temperatures to be easily tailored.
      PubDate: 2016-11-03T08:30:51.709228-05:
      DOI: 10.1002/adfm.201603364
  • Real-Time Probing Nanopore-in-Nanogap Plasmonic Coupling Effect on Silver
           Supercrystals with Surface-Enhanced Raman Spectroscopy
    • Authors: Cong Ma; Qiangqiang Gao, Wei Hong, Jie Fan, Jixiang Fang
      Abstract: Nanopore structures have displayed attractive prospects in diverse important applications such as nanopore-based biosensors and enhanced spectroscopy. However, on the one hand, the fabrication techniques to obtain sub-10 nm sized nanopores so far is very limited. On the other hand, the electromagnetic enhancement of nanopores is still relatively low. In this work, using a facile chemical etching strategy on 2D plasmonic Ag nanoparticle supercrystals, fine nanopore arrays with sub-10 nm pore size have been successfully fabricated and a “nanopore-in-nanogap” hybrid plasmon mode has been investigated. An in situ etching and surface-enhanced Raman spectroscopy (SERS) detection indicate that novel hybrid plasmon structure may create an enhanced electromagnetic coupling and increase SERS signal at ≈10× magnification. The breaking of plasmon bonding dipolar mode and generation of antibonding-like plasmon mode contribute to this enhanced electromagnetic coupling. The facile etching strategy, as a common approach, may open the doors for the fabrication of nanopores in various compositions for numerous applications.Using a facile chemical etching strategy on 2D plasmonic Ag NP supercrystals, fine nanopore arrays with sub-10 nm pore size have been successfully fabricated and a “nanopore-in-nanogap” hybrid plasmon mode has been investigated. In situ etching and surface enhanced Raman spectroscopy (SERS) detection indicate that novel hybrid plasmon structure may create an enhanced electromagnetic coupling and increase the SERS signal at ≈10× magnification.
      PubDate: 2016-11-03T08:30:45.244925-05:
      DOI: 10.1002/adfm.201603233
  • Two-Dimensional Non-Layered Materials: Synthesis, Properties and
    • Authors: Feng Wang; Zhenxing Wang, Tofik Ahmed Shifa, Yao Wen, Fengmei Wang, Xueying Zhan, Qisheng Wang, Kai Xu, Yun Huang, Lei Yin, Chao Jiang, Jun He
      Abstract: Holding novel physical properties, high flexibility and strong integration ability with Si-based electronic devices, two-dimensional (2D) non-layered materials have received considerable attentions in recent years. To achieve the 2D anisotropic growth, various strategies have been developed. And a variety of applications have been demonstrated. This review provides an overview on the recent progress of this material family. The scope will cover the preparation strategies, including dry methods and wet chemical approaches, as well as the applications in catalysis, energy conversion and storage, optoelectronic devices and topological crystalline insulators. Conclusion and future perspectives are also given.Two-dimensional non-layered materials have received considerable attentions in recent years. This review provides an overview on the recent progress of this material family by covering the preparation strategies as well as the applications in catalysis, energy conversion, energy storage, optoelectronic devices, and topological crystalline insulators, and covers future perspectives.
      PubDate: 2016-11-03T08:26:18.656268-05:
      DOI: 10.1002/adfm.201603254
  • Single-Thread-Based Wearable and Highly Stretchable Triboelectric
           Nanogenerators and Their Applications in Cloth-Based Self-Powered
           Human-Interactive and Biomedical Sensing
    • Authors: Ying-Chih Lai; Jianan Deng, Steven L. Zhang, Simiao Niu, Hengyu Guo, Zhong Lin Wang
      Abstract: The development of wearable and large-area fabric energy harvester and sensor has received great attention due to their promising applications in next-generation autonomous and wearable healthcare technologies. Here, a new type of “single” thread-based triboelectric nanogenerator (TENG) and its uses in elastically textile-based energy harvesting and sensing have been demonstrated. The energy-harvesting thread composed by one silicone-rubber-coated stainless-steel thread can extract energy during contact with skin. With sewing the energy-harvesting thread into a serpentine shape on an elastic textile, a highly stretchable and scalable TENG textile is realized to scavenge various kinds of human-motion energy. The collected energy is capable to sustainably power a commercial smart watch. Moreover, the simplified single triboelectric thread can be applied in a wide range of thread-based self-powered and active sensing uses, including gesture sensing, human-interactive interfaces, and human physiological signal monitoring. After integration with microcontrollers, more complicated systems, such as wireless wearable keyboards and smart beds, are demonstrated. These results show that the newly designed single-thread-based TENG, with the advantage of interactive, responsive, sewable, and conformal features, can meet application needs of a vast variety of fields, ranging from wearable and stretchable energy harvesters to smart cloth-based articles.A new single-thread-based triboelectric nanogenerator (TENG) as well as related elastic and wearable large-area energy-harvesting textiles and various cloth-based applications are presented. The TENG with only one triboelectric thread can generate electricity from skin contact. The simplified structures will meet various application needs ranging from wearable and stretchable energy harvesting, self-powered active sensing, to various human-interactive uses.
      PubDate: 2016-11-03T08:26:05.487222-05:
      DOI: 10.1002/adfm.201604462
  • A Novel Ultrafine Needle (UN) for Innocuous and Efficient Subcutaneous
           Insulin Delivery
    • Authors: Cheng Guo Li; Yonghao Ma, Inyoung Huh, Shayan Fakhraei Lahiji, Sang-Guk Lee, Hyungil Jung
      Abstract: Subcutaneous (SC) insulin injection has been demonstrated to be the most effective method for treatment of diabetes mellitus but is conventionally performed by hypodermic needles, leading to poor management of diabetes because of the pain, needle phobia, and tissue trauma. Identification of a viable, safe, and pain-free alternative method has been a longstanding challenge in modern health care. Here, the thermoplastic droplet stretching technique is developed to create an ultrahigh-aspect-ratio needle mold with simple microstructure control. The optimized ultrafine needle (UN) with 4 mm length, minimized 120 µm outer diameter, and 15° sharp bevel angle is formed via electroplating of a metallic layer on the surface of a needle mold with forcing sharp tip. This novel UN enables minimally invasive 4 mm skin insertion to deliver insulin in the targeted SC layer. The similar relative areas under the curves of insulin concentration within UN and 31G needle in vivo insulin administration indicate that UN can ensure stable insulin absorption for secure blood glucose management. Additionally, the proposed fabrication method may facilitate industrialization and commercialization of the UN, holding great promise for replacement of hypodermic needles and for improvement of quality of life among patients with diabetes.A new subcutaneous drug delivery system, ultrafine needle (UN), is invented to perform innocuous and efficient subcutaneous insulin injection. The optimized UN can be obtained directly via a thermoplastic droplet stretching technique with controlled shape. The smaller tissue damage and highly accurate and reproducible subcutaneous insulin delivery via the UN show great potential for the improvement of diabetics' quality of life.
      PubDate: 2016-11-03T07:46:33.112571-05:
      DOI: 10.1002/adfm.201603228
  • Electrospun Photocrosslinkable Hydrogel Fibrous Scaffolds for Rapid In
           Vivo Vascularized Skin Flap Regeneration
    • Authors: Xiaoming Sun; Qi Lang, Hongbo Zhang, Liying Cheng, Ying Zhang, Guoqing Pan, Xin Zhao, Huilin Yang, Yuguang Zhang, Hélder A. Santos, Wenguo Cui
      Abstract: Distal necrosis of random skin flap is always clinical problematic in plastic surgery. The development of 3D functional vascular networks is fundamental for the survival of a local random skin flap. Herein, an effective technique on constructing 3D fibrous scaffolds for accelerated vascularization is demonstrated using a photocrosslinkable natural hydrogel based on gelatin methacryloyl (GelMA) by electrospinning. It is found that the ultraviolet (UV) photocrosslinkable gelatin electrospun hydrogel fibrous membranes exhibit soft adjustable mechanical properties and controllable degradation properties. Furthermore, it is observed that the optimized hydrogel scaffolds can support endothelial cells and dermal fibroblasts adhesion, proliferation, and migration into the scaffolds, which facilitates vascularization. Importantly, a rapid formation of tubes is observed after 3 d seeding of endothelial cells. After GelMA fibrous scaffold implantation below the skin flap in a rat model, it is found that the flap survival rate is higher than the control group, and there is more microvascular formation, which is potentially beneficial for the flap tissue vascularization. These data suggest that GelMA hydrogels can be used for biomedical applications that require the formation of microvascular networks, including the development of complex engineered tissues.An electrospun hydrogel fibrous scaffold based on photocrosslinkable gelatin for accelerating vascularization is reported. The scaffold exhibits not only hydrogel properties but also maintains 3D spatial structure, which greatly stimulates 3D cells growth and subsequent vascularization process. Comparing to the conventional hydrogel, the hydrogel fibrous scaffold is very promising for repairing random skin flaps.
      PubDate: 2016-11-02T08:06:20.542898-05:
      DOI: 10.1002/adfm.201604617
  • White-Emitting Protein Nanoparticles for Cell-Entry and pH Sensing
    • Authors: Bobbi S. Stromer; Challa Vijaya Kumar
      Abstract: Facile synthesis of white-emitting, protein-based, metal-free, stable, nontoxic, and pH sensitive, advanced functional nanoparticles (GlowDots), as alternatives to quantum dots, is reported here. Controlled cross-linking of bovine serum albumin resulted in facile formation of spherical nanoparticles of 35 nm in diameter with a sharp size distribution (±10 nm), which were then conjugated with specific dyes to produce white-emitting particles with tunable excitation wavelengths. Chemical novelty is that the particle size, size distribution, stability, surface chemistry, and emission properties are under full chemical control where the size and absorption/emission properties are independently tuned. Up to 100 dye molecules were attached to each particle, on an average, and hence, particles acquired strong absorption cross-sections as well as high brightness. White fluorescence of GlowDots is strongly sensitive to pH over a range of pH 2–11, and pH-induced emission changes are fully reversible. The particles readily entered HeLa cells and emission color depended on particle location in the live cells, which is most likely due to the local environment surrounding the particles. These are the very first reports of white-emitting advanced functional nanoparticles that are biodegradable, sensitive to pH, and amenable for live cell imaging to probe the subcellular compartments.White-emitting protein nanoparticles of controlled size, size distribution, and surface chemistry for cellular imaging, as alternatives to quantum dots, are reported. These are stable and their white emission is sensitive to pH from 2 to 11, with the largest known range. These entered live cells rapidly and their emission color depended on particle location within the cells.
      PubDate: 2016-11-02T08:05:56.858822-05:
      DOI: 10.1002/adfm.201603874
  • Two-Dimensional Boron Crystals: Structural Stability, Tunable Properties,
           Fabrications and Applications
    • Authors: Xu Sun; Xiaofei Liu, Jun Yin, Jin Yu, Yao Li, Yang Hang, Xiaocheng Zhou, Maolin Yu, Jidong Li, Guoan Tai, Wanlin Guo
      Abstract: Boron, as a unique element nearest to carbon in the periodic table, has been predicted to form many distinctive two-dimensional (2D) structures that significantly differ from other well-studied 2D materials, owning to its exceptional ability to form strong covalent two-center-two-electron bonds as well as stable electron-deficient multi-center-two-electron bonds. Until recently, the successful syntheses of atomically thin crystalline 2D boron sheets (i.e., borophenes) provoked growing passion in 2D boron crystals. In this feature article, we present a survey of the latest achievements on 2D boron structures, starting from a concise introduction of the structures and properties of the bulk allotropes of boron, boron clusters, and especially potential building blocks for 2D boron crystals. Then we review important achievements and the current status of research on single-layered metallic borophene, and discuss 2D few-layered boron sheets, from their possible structures to tunable properties and potential applications in electronics, spintronics, and photoelectronics. We also systematically investigate the stability and functionalization of 2D icosahedral boron sheets in comparison with borophenes through first-principles studies. Finally, we present an outlook on the advance in fabrications of 2D boron sheets, and the challenges and prospects in the realm of 2D boron crystals.Boron bulk allotropes and clusters with unique bonding and structures have drawn long-standing interest. Now, boron of a new dimensionality, namely 2D boron crystals, has emerged into the vision of scientific communities, especially with the success of their experimental synthesis achieved in the last year. Here, we review state-of-the-art experimental and theoretical achievements on 2D boron crystals, with special attention paid to their possible structures, tunable properties, and potential applications.
      PubDate: 2016-11-02T08:02:31.290223-05:
      DOI: 10.1002/adfm.201603300
  • Engineered Elastomer Substrates for Guided Assembly of Complex 3D
           Mesostructures by Spatially Nonuniform Compressive Buckling
    • Authors: Kewang Nan; Haiwen Luan, Zheng Yan, Xin Ning, Yiqi Wang, Ao Wang, Juntong Wang, Mengdi Han, Matthew Chang, Kan Li, Yutong Zhang, Wen Huang, Yeguang Xue, Yonggang Huang, Yihui Zhang, John A. Rogers
      Abstract: Approaches capable of creating 3D mesostructures in advanced materials (device-grade semiconductors, electroactive polymers, etc.) are of increasing interest in modern materials research. A versatile set of approaches exploits transformation of planar precursors into 3D architectures through the action of compressive forces associated with release of prestrain in a supporting elastomer substrate. Although a diverse set of 3D structures can be realized in nearly any class of material in this way, all previously reported demonstrations lack the ability to vary the degree of compression imparted to different regions of the 2D precursor, thus constraining the diversity of 3D geometries. This paper presents a set of ideas in materials and mechanics in which elastomeric substrates with engineered distributions of thickness yield desired strain distributions for targeted control over resultant 3D mesostructures geometries. This approach is compatible with a broad range of advanced functional materials from device-grade semiconductors to commercially available thin films, over length scales from tens of micrometers to several millimeters. A wide range of 3D structures can be produced in this way, some of which have direct relevance to applications in tunable optics and stretchable electronics.This work introduces approaches to assemble complex 3D mesostructures via compressive buckling induced by elastomer substrates with spatially engineered distributions of strain. Systematic studies using combined theoretical modeling and experiment illustrate the compatibility of the approach with advanced electronic materials and planar semiconductor technologies, and representative 3D structures with potential utility in tunable optics and stretchable electronics are highlighted.
      PubDate: 2016-11-02T08:02:18.344982-05:
      DOI: 10.1002/adfm.201604281
  • Carbonized Cotton Fabric for High-Performance Wearable Strain Sensors
    • Authors: Mingchao Zhang; Chunya Wang, Huimin Wang, Muqiang Jian, Xiangyang Hao, Yingying Zhang
      Abstract: Recent years have witnessed the booming development of flexible strain sensors. To date, it is still a great challenge to fabricate strain sensors with both large workable strain range and high sensitivity. Cotton is an abundant supplied natural material composed of cellulose fibers and has been widely used for textiles and clothing. In this work, the fabrication of highly sensitive wearable strain sensors based on commercial plain weave cotton fabric, which is the most popular fabric for clothes, is demonstrated through a low-cost and scalable process. The strain sensors based on carbonized cotton fabric exhibit fascinating performance, including large workable strain range (>140%), superior sensitivity (gauge factor of 25 in strain of 0%–80% and that of 64 in strain of 80%–140%), inconspicuous drift, and long-term stability, simultaneously offering advantages of low cost and simplicity in device fabrication and versatility in applications. Notably, the strain sensor can detect a subtle strain of as low as 0.02%. Based on its superior performance, its applications in monitoring both vigorous and subtle human motions are demonstrated, showing its tremendous potential for applications in wearable electronics and intelligent robots.Based on carbonized plain weave cotton fabric, a wearable strain sensor with high sensitivity and large workable strain range (up to 140%) is fabricated through a cost-effective, scalable, and green process. Its working mechanism is investigated and its application in detection of both subtle and large deformation of the human body is demonstrated, promising great potential in wearable electronics.
      PubDate: 2016-11-02T08:02:01.433792-05:
      DOI: 10.1002/adfm.201604795
  • 3D Metal Carbide@Mesoporous Carbon Hybrid Architecture as a New
           Polysulfide Reservoir for Lithium-Sulfur Batteries
    • Authors: Weizhai Bao; Dawei Su, Wenxue Zhang, Xin Guo, Guoxiu Wang
      Abstract: 3D metal carbide@mesoporous carbon hybrid architecture (Ti3C2Tx@Meso-C, TX ≈ FxOy) is synthesised and applied as cathode material hosts for lithium-sulfur batteries. Exfoliated-metal carbide (Ti3C2Tx) nanosheets have high electronic conductivity and contain rich functional groups for effective trapping of polysulfides. Mesoporous carbon with a robust porous structure provides sufficient spaces for loading sulfur and effectively cushion the volumetric expansion of sulfur cathodes. Theoretical calculations have confirmed that metal carbide can absorb sulfur and polysulfides, therefore extending the cycling performance. The Ti3C2Tx@Meso-C/S cathodes have achieved a high capacity of 1225.8 mAh g−1 and more than 300 cycles at the C/2 current rate. The Ti3C2Tx@Meso-C hybrid architecture is a promising cathode host material for lithium-sulfur batteries.Metal carbide@mesoporous carbon hybrid architecture (Ti3C2Tx@Meso-C) with a hierarchical architecture provides new strategies to suppress the shuttle effect of polysulfides for lithium sulfur batteries via inherently active 2D functional surfaces to chemically bond intermediate polysulfides. Ti3C2Tx@Meso-C/S cathode demonstrates an enhanced electrochemical performance for lithium-sulfur batteries, including a high specific capacity, good rate performance, and excellent cycling stability.
      PubDate: 2016-10-31T05:11:03.380014-05:
      DOI: 10.1002/adfm.201603704
  • Percolation-Controlled Metal/Polyelectrolyte Complexed Films for
           All-Solution-Processable Electrical Conductors
    • Authors: Min Jun Oh; Young Hun Kim, Gwan Hyun Choi, A. Reum Park, Yong Man Lee, Byeonghak Park, Chang Hyun Pang, Tae-il Kim, Pil J. Yoo
      Abstract: The use of solution-processable electrically conducting films is imperative for realizing next-generation flexible and wearable devices in a large-scale and economically viable way. However, the conventional approach of simply complexing metallic nanoparticles with a polymeric medium leads to a tradeoff between electrical conductivity and material properties. To address this issue, in this study, a novel strategy is presented for fabricating all-solution-processable conducting films by means of metal/polyelectrolyte complexation to achieve controlled electrical percolation; this simultaneously imparts superior electrical conductivity and good mechanical properties. A polymeric matrix comprised of polyelectrolyte multilayers is first formed using layer-by-layer assembly, and then Ag nanoparticles are gradually synthesized and gradationally distributed inside the polymeric matrix by means of a subsequent procedure of repeated cationic exchange and reduction. During this process, electrical percolation between Ag nanoparticles and networking of electrical pathways is facilitated in the surface region of the complexed film, providing outstanding electrical conductivity only one order of magnitude less than that of metallic Ag. At the same time, the polymer-rich underlying region imparts strong, yet compliant, binding characteristics to the upper Ag-containing conducting region while allowing highly flexible mechanical deformations of bending and folding, which consequently makes the system outperform existing materials.Highly electroconductive, flexible, and durable Ag/polymer complexed films are synthesized by an all-solution-processing approach. The percolation networks of Ag nanoparticles are preferentially formed on the surface region of the polyelectrolyte multilayer assembled films, which synergistically imparts both high electrical conductivity (>104 S cm−1) and mechanical flexibility (>10 000 cycles of bending with a radius of 200 μm).
      PubDate: 2016-10-31T05:10:55.786892-05:
      DOI: 10.1002/adfm.201603863
  • Intraperitoneal Administration of Biointerface-Camouflaged Upconversion
           Nanoparticles for Contrast Enhanced Imaging of Pancreatic Cancer
    • Authors: Wei Yuan; Dongpeng Yang, Qianqian Su, Xingjun Zhu, Tianye Cao, Yun Sun, Yu Dai, Wei Feng, Fuyou Li
      Abstract: Pancreatic cancer has one of the highest fatality rates of all diseases, but poor drug availability after intravenous (IV) administration has hindered the diagnosis and treatment of patients. Herein, the authors report a novel strategy, combining intraperitoneal administration and phosphatidylcholine-camouflaged NaLuF4:Yb,Tm/NaLuF4/NaDyF4 upconversion nanoparticles (UCNP@PC) to gain the enhanced dual-modal imaging (upconversion luminescence/magnetic resonance imaging) of orthotopic pancreatic cancer. Remarkably, the authors observe a 16-fold improvement in the efficacy of utilization promoted intraperitoneally administered UCNP@PC in monitoring orthotopic pancreatic cancer compared with IV approach. Benefiting from modification with phosphatidylcholine, a major component of cell membranes, the optimized nanostructures show excellent biocompatibility and are rapidly excreted via the bile pathway after their intraperitoneal administration. The integration of the advanced design of UCNP@PC and the optimal drug administration route also give a general strategy for the advanced diagnosis and treatment of a series of intraperitoneal cancers.A biointerface camouflaged upconversion nanoparticle is developed to enhance diagnose orthotopic pancreatic cancer through intraperitoneal administration. By using biomimetic ligand as surface modification, excellent biocompatibility and rapid clearance can be realized. Combined upconversion and T2-weighted MR imaging monitor the promoted enrichment for the tumor based on significant affinity to both tumor related cells and tumor rough surface lacking physiological protection.
      PubDate: 2016-10-31T05:10:49.391751-05:
      DOI: 10.1002/adfm.201603907
  • Suppression of Defects and Deep Levels Using Isoelectronic Tungsten
           Substitution in Monolayer MoSe2
    • Authors: Xufan Li; Alexander A. Puretzky, Xiahan Sang, Santosh KC, Mengkun Tian, Frank Ceballos, Masoud Mahjouri-Samani, Kai Wang, Raymond R. Unocic, Hui Zhao, Gerd Duscher, Valentino R. Cooper, Christopher M. Rouleau, David B. Geohegan, Kai Xiao
      Abstract: Defects formed during chemical vapor deposition (CVD) of two-dimensional (2D) transition metal dichalcogenides (TMDs) currently limit their quality and optoelectronic properties. Effective synthesis and processing strategies to suppress defects and enhance the quality of 2D TMDs are urgently needed to enable next generation optoelectronic devices. In this work, isoelectronic doping is presented as a new strategy to form stable alloys and suppress defects and enhance photoluminescence (PL) in CVD-grown TMD monolayers. The isoelectronic substitution of W atoms for Mo atoms in CVD-grown monolayers of Mo1–xWxSe2 (0 < x < 0.18) is shown to effectively suppress Se vacancy concentration by 50% compared to those found in pristine MoSe2 monolayers, resulting in a decrease in defect-mediated nonradiative recombination, ≈10 times more intense PL, and an increase in the carrier lifetime by a factor of 3. Theoretical predictions reveal that isoelectronic W alloying to form Mo1–xWxSe2 monolayers raises the energy of deep level defects in MoSe2 to enable faster quenching, which is confirmed by low temperature (4–125 K) PL from defect-related localized states. Isoelectronic substitution therefore appears to be a promising synthetic method to control the heterogeneity of 2D TMDs to realize the scalable production of high performance optoelectronic and electronic devices.Isoelectronic tungsten alloying in MoSe2 monolayers, forming Mo1–xWxSe2, suppresses both the formation of Se vacancies in the lattice and the deep levels in the electronic bandgap. As a result, the photoluminescence is greatly enhanced by up to 10 times.
      PubDate: 2016-10-31T05:10:40.076648-05:
      DOI: 10.1002/adfm.201603850
  • Recent Advances in Soft Materials to Build and Functionalize Hard
           Structures for Electrochemical Energy Storage and In situ Electrochemical
           Molecular Biosensing
    • Authors: Chun Xian Guo; Chang Ming Li
      Abstract: Soft materials such as carbon materials, polymers and macromolecules possess rich functional groups and have become an important research filed in material science and engineering but they lack high durability and mechanical rigidity. Hard structures can provide stable and rigid scaffolds as well as hierarchically porous structures for superior physical properties; however, they often suffer from relatively poor surface chemistry. Construction of soft materials functionalized hard structures often generates new composite materials with unique physico-chemical properties for synergistically boosting high-efficient energy conversion/storage and biosensing. In this review, starting with introduction of fundamentals and properties of soft materials and hard structures, advances in fabrications and characterizations of the composite materials are discussed. The excellent physico-chemical and electrochemical properties of the soft materials-built and functionalized composite materials as well as their applications as electrode materials in solar cells, fuel cells, electrochemical water splitting, lithium-ion batteries/lithium-sulfur batteries/supercapacitors, and in situ molecular biosensing for greatly improved performance are surveyed. The performance enhancement mechanisms in these electrochemical systems are discussed to elicit fundamental insights. The challenges and prospects of this research area are also deliberated to inspire future improvements.This feature article summarizes recent development of functional composites of soft materials-built and functionalized hard structures and their electrode materials with unique physico-chemical properties to synergistically promote high performance of energy conversion/storage and in-situ molecular biosensing systems, and discusses their enhancement mechanisms to elicit fundamental insights, while proposing challenges and prospects in this research area.
      PubDate: 2016-10-31T03:27:40.40586-05:0
      DOI: 10.1002/adfm.201602697
  • Amine-Free Synthesis of Cesium Lead Halide Perovskite Quantum Dots for
           Efficient Light-Emitting Diodes
    • Authors: Emre Yassitepe; Zhenyu Yang, Oleksandr Voznyy, Younghoon Kim, Grant Walters, Juan Andres Castañeda, Pongsakorn Kanjanaboos, Mingjian Yuan, Xiwen Gong, Fengjia Fan, Jun Pan, Sjoerd Hoogland, Riccardo Comin, Osman M. Bakr, Lazaro A. Padilha, Ana F. Nogueira, Edward H. Sargent
      Abstract: Cesium lead halide perovskite quantum dots (PQDs) have attracted significant interest for optoelectronic applications in view of their high brightness and narrow emission linewidth at visible wavelengths. A remaining challenge is the degradation of PQDs during purification from the synthesis solution. This is attributed to proton transfer between oleic acid and oleylamine surface capping agents that leads to facile ligand loss. Here, a new synthetic method is reported that enhances the colloidal stability of PQDs by capping them solely using oleic acid (OA). Quaternary alkylammonium halides are used as precursors, eliminating the need for oleylamine. This strategy enhances the colloidal stability of OA capped PQDs during purification, allowing us to remove excess organic content in thin films. Inverted red, green, and blue PQD light-emitting diodes (LED) are fabricated for the first time with solution-processed polymer-based hole transport layers due to higher robustness of OA capped PQDs to solution processing. The blue and green LEDs exhibit threefold and tenfold improved external quantum efficiency (EQE), respectively, compared to prior related reports for amine/ammonium capped cross-linked PQDs. The brightest blue LED based on all inorganic CsPb(Br1−xClx)3 PQDs is also reported.A new synthetic method is reported that enhances the colloidal stability of CsPbX3 perovskite quantum dots (PQDs) by capping solely with oleic acid ligands. Inverted red, green, and blue PQD light-emitting diodes (LEDs) are fabricated using solution-processed polymer-based hole transport layers for the first time. The PQD-LEDs exhibit up to tenfold improvement in external quantum efficiency compared to prior reports.
      PubDate: 2016-10-31T03:26:09.676423-05:
      DOI: 10.1002/adfm.201604580
  • In Situ Fabrication of Highly Luminescent Bifunctional Amino Acid
           Crosslinked 2D/3D NH3C4H9COO(CH3NH3PbBr3)n Perovskite Films
    • Authors: Taiyang Zhang; Liqiang Xie, Liang Chen, Nanjie Guo, Ge Li, Zhongqun Tian, Bingwei Mao, Yixin Zhao
      Abstract: The perovskite quantum dots are usually synthesized by solution chemistry and then fabricated into film for device application with some extra process. Here it is reported for the first time to in situ formation of a crosslinked 2D/3D NH3C4H9COO(CH3NH3)nPbnBr3n perovskite planar films with controllable quantum confine via bifunctional amino acid crosslinkage, which is comparable to the solution chemistry synthesized CH3NH3PbBr3 quantum dots. These atomic layer controllable perovskite films are facilely fabricated and tuned by addition of bi-functional 5-aminovaleric acid (Ava) of NH2C4H9COOH into regular (CH3NH3)PbBr3 (MAPbBr3) perovskite precursor solutions. Both the NH3+ and the COO− groups of the zwitterionic amino acid are proposed to crosslink the atomic layer MAPbBr3 units via PbCOO bond and ion bond between NH3+ and [PbX6] unit. The characterizations by atomic force microscopy, scanning electron microscopy, Raman, and photoluminescence spectroscopy confirm a successful fabrication of ultrasmooth and stable film with tunable optical properties. The bifunctional crosslinked 2D/3D Ava(MAPbBr3)n perovskite films with controllable quantum confine would serve as distinct and promising materials for optical and optoelectronic applications.A novel one-step in situ formation of crosslinked 2D/3D NH3C4H9COO(CH3NH3PbBr3)n perovskite planar films with controllable quantum confines is reported, which is comparable to solution chemistry synthesized perovskite quantum dots. The zwitterionic amino acid NH2C4H9COOH (Ava) in the CH3NH3PbBr3 precursor can crosslink the atomic layer (CH3NH3PbBr3)n units by amino acids NH3+ and the COO− groups.
      PubDate: 2016-10-31T03:25:52.847424-05:
      DOI: 10.1002/adfm.201603568
  • Heteroatom (N or N-S)-Doping Induced Layered and Honeycomb Microstructures
           of Porous Carbons for CO2 Capture and Energy Applications
    • Authors: Wenjie Tian; Huayang Zhang, Hongqi Sun, Alexandra Suvorova, Martin Saunders, Moses Tade, Shaobin Wang
      Abstract: Increasing global challenges such as climate change, environmental pollution, and energy shortage have stimulated the worldwide explorations into novel and clean materials for their applications in the capture of carbon dioxide, a major greenhouse gas, and toxic pollutants, energy conversion, and storage. In this study, two microstructured carbons, namely N-doped pillaring layered carbon (NC) and N, S codoped honeycomb carbon (NSC), have been fabricated through a one-pot pyrolysis process of a mixture containing glucose, sodium bicarbonate, and urea or thiourea. The heteroatom doping is found to induce tailored microstructures featuring highly interconnected pore frameworks, high sp2-C ratios, and high surface areas. The formation mechanism of the varying pore frameworks is believed to be hydrogen-bond interactions. NSC displays a similar CO2 adsorption capacity (4.7 mmol g−1 at 0 °C), a better CO2/N2 selectivity, and higher activity in oxygen reduction reaction as compared with NC-3 (the NC sample with the highest N content of 7.3%). NSC favors an efficient four-electron reduction pathway and presents better methanol tolerance than Pt/C in alkaline media. The porous carbons also exhibit excellent rate performance as supercapacitors.N-doped layered and N, S codoped honeycomb carbons have been fabricated, and the hydrogen-bond interactions during the self-assembly process are suggested to be responsible for the formation of different pore frameworks. The tailored micropore/mesopore architecture and heteroatom doping of the porous carbons synergistically induce enhanced CO2 capture capacity/selectivity and improved oxygen reduction reaction activities.
      PubDate: 2016-10-28T08:46:28.561635-05:
      DOI: 10.1002/adfm.201603937
  • Rational Design of High-Mobility Semicrystalline Conjugated Polymers with
           Tunable Charge Polarity: Beyond Benzobisthiadiazole-Based Polymers
    • Authors: Yang Wang; Tsukasa Hasegawa, Hidetoshi Matsumoto, Takehiko Mori, Tsuyoshi Michinobu
      Abstract: High-mobility semiconducting polymers composed of arylene vinylene and dithiophene-thiadiazolobenzotriazole (SN) units are developed by three powerful design strategies, namely, backbone engineering, heteroatom substitution, and side-chain engineering. First, starting from the quaterthiophene-SN copolymer, a vinylene spacer is inserted into the quaterthiophene unit for constructing highly-planar backbones. Second, heteroatoms (O and N atoms) are incorporated into the thienylene vinylene moieties to tune the electronic properties and intermolecular interactions. Third, the alkyl side chains are optimized to tune the solubility and self-assembly properties. As a consequence, a remarkable thin film transistor performance is obtained. The very high hole mobility of 3.22 cm2 V−1 s−1 is achieved for the p-type polymer, PSNVT-DTC8, which is the highest value ever reported for the polymers based on the benzobisthiadiazole and its analogs. Moreover, heteroatom substitution efficiently varies the charge polarity of the polymers as in the case of the N atom substituted PSNVTz-DTC16 displaying n-type dominant ambipolar properties with the electron mobility of 0.16 cm2 V−1 s−1. Further studies using grazing-incidence wide-angle X-ray scattering and atomic force microscopy have revealed the high crystallinities of the polymer thin films with strong π–π interactions and suitable polymer packing orientations.An effective design strategy for producing superior semiconducting polymers is proposed. By employing this strategy, a field-effect hole mobility as high as 3.22 cm2 V−1 s−1 is achieved in the conventional top contact/bottom gate transistor based on one of the newly synthesized polymers. This value is the highest among all the reported polymers containing benzobisthiadiazole and its analogs.
      PubDate: 2016-10-28T08:46:16.625882-05:
      DOI: 10.1002/adfm.201604608
  • Desalination by Electrodialysis Using a Stack of Patterned Ion-Selective
           Hydrogels on a Microfluidic Device
    • Authors: Burcu Gumuscu; A. Sander Haase, Anne M. Benneker, Mark A. Hempenius, Albert van den Berg, Rob G. H. Lammertink, Jan C. T. Eijkel
      Abstract: This study reports a novel approach for separation of charged species using anion-exchange hydrogel (AEH) and cation-exchange hydrogel (CEH) in a microfluidic device. The capillary line pinning technique, which is applied in this study, enables in situ fabrication of alternating AEH and CEH that are placed in confined compartments. Adjacent enriched and depleted streams are obtained in continuous flow when a potential difference is applied over the hydrogel stack. The desalination performance of the microchip is demonstrated at different salt concentrations (0.01 × 10−3–1× 10−3m sodium chloride), potentials (10–100 V), current densities (12–28 A m−2), and liquid flow rates (0–5 µL min−1). It is shown that the microchip is able to remove ≈75% of the salt initially present in the depleted outlet streams at inlet stream concentrations of 1 × 10−3m sodium chloride. The miniature format enables use as a pocket-sized desalination unit, for example, for survival kits. Besides desalination, the microchip allows study of ion transport in the ion-selective hydrogels to elucidate the interplay of transport phenomena at the electrolyte–hydrogel interface during the desalination process.Microfluidic desalination using a stack of oppositely charged hydrogels. Desalted and enriched streams are obtained owing to the ion-selective transport in the charged hydrogels, which are alternatingly patterned in parallel lanes in the microchip.
      PubDate: 2016-10-28T07:25:55.04717-05:0
      DOI: 10.1002/adfm.201603242
  • Osmotic Power Generation with Positively and Negatively Charged 2D
           Nanofluidic Membrane Pairs
    • Authors: Jinzhao Ji; Qian Kang, Yi Zhou, Yaping Feng, Xi Chen, Jinying Yuan, Wei Guo, Yen Wei, Lei Jiang
      Abstract: In nature, hierarchically assembled nanoscale ionic conductors, such as ion channels and ion pumps, become the structural and functional basis of bioelectric phenomena. Recently, ion-channel-mimetic nanofluidic systems have been built into reconstructed 2D nanomaterials for energy conversion and storage as effective as the electrogenic cells. Here, a 2D-material-based nanofluidic reverse electrodialysis system, containing cascading lamellar nanochannels in oppositely charged graphene oxide membrane (GOM) pairs, is reported for efficient osmotic energy conversion. Through preassembly modification, the surface charge polarity of the 2D nanochannels can be efficiently tuned from negative (−123 mC m−2) to positive (+147 mC m−2), yielding strongly cation- or anion-selective GOMs. The complementary two-way ion diffusion leads to an efficient charge separation process, creating superposed electrochemical potential difference and ionic flux. An output power density of 0.77 W m−2 is achieved by controlled mixing concentrated (0.5 m) and diluted ionic solutions (0.01 m), which is about 54% higher than using commercial ion exchange membranes. Tandem alternating GOM pairs produce high voltage up to 2.7 V to power electronic devices. Besides simple salt solutions, various complex electrolyte solutions can be used as energy sources. These findings provide insights to construct cascading nanofluidic circuits for energy, environmental, and healthcare applications.2D-material-based high-performance osmotic energy conversion from complex ionic solutions is achieved with chemically modified, oppositely charged graphene oxide membrane (GOM) pairs. The output power density approaches 0.77 W m−2, which is 54% higher than using commercial ion-exchange membranes. Tandem GOM stacks produce high voltages up to 2.7 V to power real electronic devices. The bio-inspired 2D nanofluidic materials anticipate substantial advance in membrane-based technologies for energy, environmental, and healthcare applications.
      PubDate: 2016-10-28T07:02:44.770824-05:
      DOI: 10.1002/adfm.201603623
  • Biomaterials Act as Enhancers of Growth Factors in Bone Regeneration
    • Authors: Rui Chen; Jing Wang, Changsheng Liu
      Abstract: Inspired by the physiological events of the “wound healing cascade”, the integration of biomaterials and growth factors is generally accepted as an emerging and powerful strategy for bone regenerative therapy. As a type of biological mediator, growth factors play a key role in functional bone regeneration. In this review, recent progress in the enhancement of bone-related growth factors via a biomaterial strategy will be discussed. Two main reinforcing mechanisms, temporal regulation and efficacy manipulation, are described in detail, highlighting the potential capability of biomaterials to harness the interactions between growth factors and specific cells. The effects of biomaterials for promoting bone formation via growth factor-mediated osteogenesis are further elucidated. Finally, an outlook of the prospects in terms of superior communication among growth factors, cells, and biomaterials in the microenvironment is presented, which might provide new directions for the design of medical devices for bone regeneration.Biomaterials act as enhancers of growth factors in bone regeneration via two mechanisms: temporal regulation and efficacy manipulation. This results in extended growth factor half-lives due to effective loading and sustained release, as well as enhanced bioactivity mediated by growth factor-receptor recognition driven by the optimal orientation of growth factors and receptor localization.
      PubDate: 2016-10-28T07:02:39.133956-05:
      DOI: 10.1002/adfm.201603197
  • Zinc Oxide Nanorod-Based Piezoelectric Dermal Patch for Wound Healing
    • Authors: Suk Ho Bhang; Woo Soon Jang, Jin Han, Jeong-Kee Yoon, Wan-Geun La, Eungkyu Lee, Youn Sang Kim, Jung-Youn Shin, Tae-Jin Lee, Hong Koo Baik, Byung-Soo Kim
      Abstract: Current treatments for wound healing engage in passive healing processes and rarely participate in stimulating skin cell behaviors for active wound healing. Electric potential difference-derived electrical fields (EFs) are known to modulate skin cell behaviors. Here, a piezoelectric dermal patch is developed that can be applied on skin wound site and EF is generated to promote wound healing. The one-directionally aligned zinc oxide nanorod-based piezoelectric patch generates piezoelectric potential upon mechanical deformations induced by animal motion, and induces EF at the wound bed. In vitro and in vivo data demonstrate that the piezoelectric patch promotes the wound healing process through enhanced cellular metabolism, migration, and protein synthesis. This modality may lead to a clinically relevant piezoelectric dermal patch therapy for active wound healing.A piezoelectric patch that can be applied on skin wounds and generate electric fields (EFs) to promote wound healing is developed. The zinc oxide nanorod-based patch generates piezoelectric potential upon skin movements, and induces EF at the wound bed. In vitro and in vivo data suggest the patch promotes skin regeneration through enhanced cellular metabolism, migration, and protein synthesis.
      PubDate: 2016-10-28T07:02:31.998944-05:
      DOI: 10.1002/adfm.201603497
  • Tumor-Responsive Small Molecule Self-Assembled Nanosystem for Simultaneous
           Fluorescence Imaging and Chemotherapy of Lung Cancer
    • Authors: Yuming Yang; Caixia Yue, Yu Han, Wei Zhang, Aina He, Chunlei Zhang, Ting Yin, Qian Zhang, Jingjing Zhang, Yao Yang, Jian Ni, Jielin Sun, Daxiang Cui
      Abstract: Cancer therapeutic drugs face various transportation barriers in transit to the tumor site, making the delivery of effective drug concentrations problematic. Moreover, these drugs are very difficult to use due to their adverse off-target effects. Thus, it is very essential to develop a drug delivery system that can deliver drugs to achieve effective local concentrations without side effects on healthy tissues. Herein, the authors report a self-assembled nanodrug system in which hydrophobic antitumor drugs are packaged into nanoparticles to improve water solubility, tumor targeting ability, blood retention time, and chemotherapeutic effect. The nanodrugs are degraded into smaller ones when exposed to the tumor microenvironment, extravasated from leaky regions of the tumor vasculature, and displayed matrix metalloproteinase-2 (MMP-2)-induced degradation and antitumor property. To construct this unique system, an amphiphilic multifunctional molecule (Pep-Cy5) is synthesized by attaching a MMP-2-cleavable peptide to a hydrophobic near-infrared dye, Cy5. Two hydrophobic anticancer drugs are conjugated to Pep-Cy5 through hydrophobic interactions to form the self-assembled nanodrug system. The MMP-2-induced degradation and hydrophobic antitumor drug interchangeability features of this nanosystem enable the hydrophobic antitumor drugs to exhibit longer blood-retention times, improved intratumoral accumulation, fewer side effects, and higher anticancer efficacies compared with free drugs.Schematic illustration of self-assembly, matrix metalloproteinase-2-induced degradation process for the self-assemble nanodrugs. The hydrophobic antitumor drugs self-assembled into water-soluble nanoparticles through hydrophobic interactions with Pep-Cy5. The blue ball represents the self-assembled nanodrugs. The brown ball represents tumor tissue. The nanodrugs degrade into small particles, which readily diffuse throughout the tumor's interstitial space.
      PubDate: 2016-10-28T07:02:24.216256-05:
      DOI: 10.1002/adfm.201601369
  • A Synergetic Effect of Molecular Weight and Fluorine in All-Polymer Solar
           Cells with Enhanced Performance
    • Authors: Shanshan Chen; Yujin An, Gitish K. Dutta, Yiho Kim, Zhi-Guo Zhang, Yongfang Li, Changduk Yang
      Abstract: A synergetic effect of molecular weight (Mn) and fluorine (F) on the performance of all-polymer solar cells (all-PSCs) is comprehensively investigated by tuning the Mn of the acceptor polymer poly((N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl)-alt-5,5′-(2,2′-bithiophene)) (P(NDI2OD-T2)) and the F content of donor polymer poly(2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-dyl-alt-thiophene-2,5-diyl). Both Mn and F variations strongly influence the charge transport properties and morphology of the blend films, which have a significant impact on the photovoltaic performance of all-PSCs. In particular, the effectiveness of high Mn in increasing power conversion efficiency (PCE) can be greatly improved by the devices based on optimum F content, reaching a PCE of 7.31% from the best all-PSC combination. These findings enable us to further understand the working principles of all-PSCs with a view on achieving even higher power conversion efficiency in the future.To establish a correlation between the effects of molecular weight (Mn) and fluorine (F) on photovoltaic performance, all-polymer solar cells have been comprehensively investigated based on donor polymers of TQ family with various F content and P(NDI2OD-T2) acceptor polymers with various Mn. An efficiency of 7.31% is demonstrated by blending the optimum F content-containing donor with a high Mn acceptor.
      PubDate: 2016-10-28T07:02:10.905102-05:
      DOI: 10.1002/adfm.201603564
  • Creating the Smallest BN Nanotube from Bilayer h-BN
    • Authors: Tao Xu; Yilong Zhou, Xiaodong Tan, Kuibo Yin, Longbing He, Florian Banhart, Litao Sun
      Abstract: Single-wall nanotubes of boron nitride (BN) are among the most promising quasi-1D materials with outstanding mechanical strength. However, synthesizing them in a controlled and reproducible way remains challenging. Here the authors show a technique of creating BN tubes by cutting bilayer BN sheets with an electron beam and interconnecting the two layers at an open edge. The in situ experiments in an electron microscope show that the spontaneous interlinking of the two layers leads to flattened tubular structures when a narrow ribbon is created. Below a certain width of the ribbon, van der Waals interaction between the layers is overbalanced by the stress in the layer so that the walls separate and a tube with circular diameter forms. The smallest stable BN tubes with a diameter of 0.45 nm, corresponding to a (3,3) tube, can be produced by this technique. The diameter can only be decreased in discrete steps, showing that all possible BN tubes with a given axis alignment relative to the BN lattice can be made. This is a novel top-down approach that allows the authors to create and study a variety of ultrathin nanotubes from related 2D materials.Electron beam structuring provides a top-down approach to create boron nitride (BN) tubes by cutting bilayer BN sheets. Covalent interlayer bonds form spontaneously at two parallel zigzag edges, resulting in formation of armchair BN tubes. The diameter can only be decreased in discrete steps to 0.45 nm, corresponding to a (3,3) tube, which is the smallest tubes observed experimentally so far.
      PubDate: 2016-10-28T06:57:06.173614-05:
      DOI: 10.1002/adfm.201603897
  • Hierarchical Chemical Bonds Contributing to the Intrinsically Low Thermal
           Conductivity in α-MgAgSb Thermoelectric Materials
    • Authors: Pingjun Ying; Xin Li, Yancheng Wang, Jiong Yang, Chenguang Fu, Wenqing Zhang, Xinbing Zhao, Tiejun Zhu
      Abstract: Understanding the lattice dynamics and phonon transport from the perspective of chemical bonds is essential for improving and finding high-efficiency thermoelectric materials and for many applications. Here, the coexistence of global and local weak chemical bonds is elucidated as the origin of the intrinsically low lattice thermal conductivity of non-caged structure Nowotny–Juza compound, α-MgAgSb, which is identified as a new type of promising thermoelectric material in the temperature range of 300–550 K. The global weak bonds of the compound lead to a low sound velocity. The unique three-centered MgAgSb bonds in α-MgAgSb vibrate locally and induce low-frequency optical phonons, resulting in “rattling-like” thermal damping to further reduce the lattice thermal conductivity. The hierarchical chemical bonds originate from the low valence electron count of α-MgAgSb, with the feature shared by Nowotny–Juza compounds. Low lattice thermal conductivities are therefore highly possible in this series of compounds, which is verified by phonon and bulk modulus calculations on some of the compositions.A coexistence of hierarchical weak bonds in non-caged compound of α-MgAgSb leads to low thermal conductivity. The weak bondings are found in other typical Nowotny–Juza compounds with low valence electrons, and low lattice thermal conductivities are expectede. Future studies about Nowotny–Juza compounds are therefore encouraged in order to find compounds with low thermal conductivity and high thermoelectric efficiency.
      PubDate: 2016-10-28T06:56:47.263522-05:
      DOI: 10.1002/adfm.201604145
  • Sole Chemical Confinement of Polysulfides on Nonporous Nitrogen/Oxygen
           Dual-Doped Carbon at the Kilogram Scale for Lithium–Sulfur Batteries
    • Authors: Kan Mi; Shunwei Chen, Baojuan Xi, Shuangshuang Kai, Yong Jiang, Jinkui Feng, Yitai Qian, Shenglin Xiong
      Abstract: The exploration of inexpensive, facile, and large-scale methods to prepare carbon scaffolds for high sulfur loadings is crucial for the advancement of Li–S batteries (LSBs). Herein, the authors report a new nitrogen and oxygen in situ dual-doped nonporous carbonaceous material (NONPCM) that is composed of a myriad of graphene-analogous particles. Importantly, NONPCM could be fabricated on a kilogram scale via inexpensive and green hydrothermal-carbonization-combined methods. Many active sites on the NONPCM surface are accessible for the efficient surface-chemistry confinement of guest sulfur and its discharge product; this confinement is exclusive of physical entrapment, considering the low surface area. Electrochemical examination demonstrates excellent cycle stability and rate performance of the NONPCM (K)/S composite, even with a sulfur loading of 80 or 90 wt%. Hence, the scaffolds for LSBs exhibit potential for industrialization through further optimization and expansion of the present synthesis.A new nitrogen and oxygen in situ dual-doped nonporous carbonaceous material (NONPCM): NONPCM, composed of a myriad of graphene-analogous particles, is for the first time fabricated on a kilogram scale by a green hydrothermal method. Considering the favorable preparation and remarkable electrochemical behavior, NONPCM is a very promising candidate for sulfur scaffolds to bridge the practical applications of Li–S batteries.
      PubDate: 2016-10-28T06:52:09.270604-05:
      DOI: 10.1002/adfm.201604265
  • Carbon Ultramicropores: A New Approach to Tuning Carbon Ultramicropore
           Size at Sub-Angstrom Level for Maximizing Specific Capacitance and CO2
           Uptake (Adv. Funct. Mater. 44/2016)
    • Authors: Jin Zhou; Zhaohui Li, Wei Xing, Honglong Shen, Xu Bi, Tingting Zhu, Zhipeng Qiu, Shuping Zhuo
      Pages: 7945 - 7945
      Abstract: A new approach to precisely tuning carbon ultra-micropore size at sub-angstrom level by exploiting the varying activating strength and size of the alkali ions is presented by W. Xing, S. Zhou, and co-workers on page 7955. This adjustable pore size is perfectly adapted to the electrolyte ions and CO2 molecules, resulting in its outstanding capacitive performance and CO2 uptake.
      PubDate: 2016-11-21T07:56:12.636683-05:
      DOI: 10.1002/adfm.201670286
  • Cycling-Stable Cathodes: Hydroxyapatite/Mesoporous Graphene/Single-Walled
           Carbon Nanotubes Freestanding Flexible Hybrid Membranes for Regenerative
           Medicine (Adv. Funct. Mater. 44/2016)
    • Authors: Rujing Zhang; Noah Metoki, Orna Sharabani-Yosef, Hongwei Zhu, Noam Eliaz
      Pages: 7946 - 7946
      Abstract: On page 7965, H. W. Zhu, N. Eliaz, and co-workers report the synthesis of well-aligned biomimetic hexagonal bars of hydroxyapatite on flexible, freestanding mesoporous graphene/single-walled carbon nanotubes hybrid membrane. This membrane holds great promise in regenerative medicine applications such as patches for bone repair and strips for spine fusion.
      PubDate: 2016-11-21T07:56:13.188607-05:
      DOI: 10.1002/adfm.201670287
  • Contents: (Adv. Funct. Mater. 44/2016)
    • Pages: 7947 - 7954
      PubDate: 2016-11-21T07:56:11.592516-05:
      DOI: 10.1002/adfm.201670288
  • A Robust Design for Cellular Vehicles of Gold Nanorods for Multimodal
    • Authors: F. Ratto; S. Centi, C. Avigo, C. Borri, F. Tatini, L. Cavigli, C. Kusmic, B. Lelli, S. Lai, S. Colagrande, F. Faita, L. Menichetti, R. Pini
      Pages: 7954 - 7954
      PubDate: 2016-11-21T07:56:12.139424-05:
      DOI: 10.1002/adfm.201605305
  • A New Approach to Tuning Carbon Ultramicropore Size at Sub-Angstrom Level
           for Maximizing Specific Capacitance and CO2 Uptake
    • Authors: Jin Zhou; Zhaohui Li, Wei Xing, Honglong Shen, Xu Bi, Tingting Zhu, Zhipeng Qiu, Shuping Zhuo
      Pages: 7955 - 7964
      Abstract: Ultramicroporous carbon materials with uniform pore size accurately adjusted to the dimension of electrolyte ions or CO2 molecule are highly desirable for maximizing specific capacitance and CO2 uptake. However, efficient ways to fine-tuning ultramicropore size at angstrom level are scarce. A completely new approach to precisely tuning carbon ultramicropore size at sub-angstrom level is proposed herein. Due to the varying activating strength and size of the alkali ions, the ultramicropore size can be finely tuned in the range of 0.60–0.76 nm as the activation ion varies from Li+ to Cs+. The carbons prepared by direct pyrolysis of alkali salts of carboxylic phenolic resins yield ultrahigh capacitances of up to 223 F g-1 (205 F cm-3) in ionic liquid electrolyte, and superior CO2 uptake of 5.20 mmol g-1 at 1.0 bar and 25 °C. Such outstanding performance of the finely tuned carbons lies in its adjustable pore size perfectly adapted to the electrolyte ions and CO2 molecule. This work paves the way for a new route to finely tuning ultramicropore size at the sub-angstrom level in carbon materials.A new approach to tune carbon ultramicropore size at sub-angstrom level is proposed. Due to the varying activating strength and size of the alkali ions, pore size can be finely tuned from 0.60 to 0.76 nm. The prepared carbons show ultra­high specific capacitance of 205 F cm−3 in ionic liquid and superior CO2 uptake of 5.20 mmol g−1.
      PubDate: 2016-08-29T02:07:01.344041-05:
      DOI: 10.1002/adfm.201601904
  • Hydroxyapatite/Mesoporous Graphene/Single-Walled Carbon Nanotubes
           Freestanding Flexible Hybrid Membranes for Regenerative Medicine
    • Authors: Rujing Zhang; Noah Metoki, Orna Sharabani-Yosef, Hongwei Zhu, Noam Eliaz
      Pages: 7965 - 7974
      Abstract: Freestanding flexible membranes based on biocompatible calcium phosphates are of great interest in regenerative medicine. Here, the authors report the first synthesis of well-aligned biomimetic hexagonal bars of hydroxyapatite (HAp) on flexible, freestanding mesoporous graphene/single-walled carbon nanotubes (MG/SWCNT) hybrid membranes. The chemical composition and surface morphology of the HAp coating resemble those of biological apatite. Nitrogen doping and oxygen plasma etching of the MG/SWCNT membranes increase the density of nucleation sites and yield more uniform coatings. This novel membrane favors the attachment and proliferation of human fetal osteoblast (hFOB) osteoprogenitor cells. When soaked in simulated body fluid, enhanced in vitro biomineralization occurs on the hybrid membranes. This hybrid membrane holds great promise in biomedical applications such as patches and strips for spine fusion, bone repair, and restoration of tooth enamel.Flexible, freestanding mesoporous graphene/single-walled carbon nanotubes hybrid membranes are electrodeposited with well-aligned biomimetic hydroxyapatite. Nitrogen doping and oxygen plasma etching of the substrates improve the coating. The coated membranes show excellent biocompatibility, bioactivity, and biomineralization in vitro. These novel membranes hold great promise in regenerative medicine applications such as bone repair and restoration of tooth enamel.
      PubDate: 2016-10-13T01:27:23.665663-05:
      DOI: 10.1002/adfm.201602088
  • Assigning Electronic States in Carbon Nanodots
    • Authors: Volker Strauss; Axel Kahnt, Eva M. Zolnhofer, Karsten Meyer, Harald Maid, Christian Placht, Walter Bauer, Thomas J. Nacken, Wolfgang Peukert, Sebastian H. Etschel, Marcus Halik, Dirk M. Guldi
      Pages: 7975 - 7985
      Abstract: Luminescent carbon nanodots exhibit enormous potential to be used as functional building blocks in energy conversion devices. Their intrinsic heterogeneity, however, hinders a thorough characterization and subsequently their applicability. In this work, the spectroscopic and electrochemical properties of prototype carbon nanodots were thoroughly studied in solution. Spectro-electrochemical experiments revealed information on the spectral features of several oxidized and reduced species of our carbon nanodots. Therefore, these experiments were complemented with pulse radiolysis where the spectral signature of the one-electron oxidized and reduced forms were identified. Both, electrochemically and radiolytically reduced and oxidized products show high reactivity in solution which correlates with an open-shell character, detected by paramagnetic resonance spectroscopy. The herein presented studies help to understand the complex nature of carbon nanodots and serve to overcome difficulties in device fabrication.The electrochemical properties and the response of the spectral features toward electrical potentials of prototype carbon nanodots are investigated. Open-shell character and high reactivity of the products are evident from electron paramagnetic resonance spectroscopy and pulse radiolytic experiments.
      PubDate: 2016-09-13T07:06:56.173331-05:
      DOI: 10.1002/adfm.201602325
  • Electric Field and Gradient Microstructure for Cooperative Driving of
           Directional Motion of Underwater Oil Droplets
    • Authors: Dongliang Tian; Linlin He, Na Zhang, Xi Zheng, Yuhai Dou, Xiaofang Zhang, Zhenyan Guo, Lei Jiang
      Pages: 7986 - 7992
      Abstract: Driving a liquid droplet with control of directional motion on a solid surface, by introducing a surface wettability gradient or external stimuli, has attracted considerable research attention. There still remain challenges, however, due to the slow response rate and slow speed of continuous liquid droplet motion on the structured surface. Here, an approach to continuously drive the underwater oil droplet with control of directional motion by the cooperative effects of an electric field and the gradient of a porous polystyrene microstructure is demonstrated. The gradient microstructure induces the liquid droplet to take on an asymmetrical shape, causing unbalanced pressure on both ends to orient the droplet for motion in a particular direction. Meanwhile, the electric field decreases the contact area and the corresponding viscous drag between the droplet and the gradient-structured surface. Then, the unbalanced pressure pushes the underwater oil droplet to move directionally and continuously at a certain voltage. This work provides a new strategy to control underwater oil droplets and realize unidirectional motion. It is also promising for the design of new smart interface materials for applications such as electrofluidic displays, biological cell and particle manipulation, and other types of microfluidic devices.An approach to continuously drive the directional motion of an underwater oil droplet by the cooperative effects of electric field and gradient microstructure is demonstrated. This provides a new strategy to continuously drive and control underwater oil droplets and is promising for the design of new functional interface materials for broad application.
      PubDate: 2016-09-05T01:30:33.545226-05:
      DOI: 10.1002/adfm.201601843
  • Diagnostics: High Performance, Multiplexed Lung Cancer Biomarker Detection
           on a Plasmonic Gold Chip (Adv. Funct. Mater. 44/2016)
    • Authors: Bin Liu; Yaling Li, Hao Wan, Lin Wang, Wei Xu, Shoujun Zhu, Yongye Liang, Bo Zhang, Jiatao Lou, Hongjie Dai, Kun Qian
      Pages: 7993 - 7993
      Abstract: A plasmonic gold (pGOLD) chip-based diagnosis of lung cancer is performed through multiplexed near-infrared detection of biomarkers in patient serum samples. On page 7994, J. Lou, K. Qian, and co-workers demonstrate that the device offers markedly improved limit-of-quantification, limit-of-detection, reproducibility, and higher diagnostic sensitivity and specificity over traditional biochips and Luminex technology currently in use in hospitals from just 10 μl of human serum.
      PubDate: 2016-11-21T07:56:10.30138-05:0
      DOI: 10.1002/adfm.201670290
  • High Performance, Multiplexed Lung Cancer Biomarker Detection on a
           Plasmonic Gold Chip
    • Authors: Bin Liu; Yaling Li, Hao Wan, Lin Wang, Wei Xu, Shoujun Zhu, Yongye Liang, Bo Zhang, Jiatao Lou, Hongjie Dai, Kun Qian
      Pages: 7994 - 8002
      Abstract: Diagnosis of lung cancer is performed using a plasmonic gold (pGOLD) chip through multiplexed near-infrared (NIR) detection of carcino-embryonic antigen (CEA), Cyfra21-1, and neuron-specific enolase (NSE) in the serum samples of patients. With ≈50-fold enhancement of NIR fluorescence, multiplexed microarray analysis of CEA, Cyfra21-1, and NSE in 10 μL of human serum or whole blood samples on pGOLD chip leads to markedly improved limit-of-quantification, limit-of-detection, reproducibility, and higher diagnostic sensitivity and specificity compared to traditional biochips and Luminex technology currently in use in hospitals.Plasmonic gold (pGOLD) chip-based diagnosis of lung cancer is performed using multiplexed near-infrared detection of biomarkers in the serum samples of patients. Multiplexed microarray analysis of biomarkers in 10 μL of human serum on a pGOLD chip leads to markedly improved limit-of-quantification, limit-of-detection, reproducibility, and higher diagnostic sensitivity and specificity compared to traditional biochips and Luminex technology currently in use in hospitals.
      PubDate: 2016-09-26T08:30:38.800978-05:
      DOI: 10.1002/adfm.201603547
  • Electrochemically Driven Hydroxyapatite Nanoparticles Coating of Medical
    • Authors: Ori Geuli; Noah Metoki, Noam Eliaz, Daniel Mandler
      Pages: 8003 - 8010
      Abstract: Calcium phosphates are of great interest for biomedical applications such as bone tissue engineering, bone fillers, drug and gene delivery, and orthopedic and dental implant coating. Here, the first electrochemically driven coating of medical implants using hydroxyapatite (HAp) nanoparticles (NPs) as building blocks is reported. This uncommon combination offers a simple, straightforward, and economic process with well controllable, pure, single-phase HAp. Crystalline, pure HAp NPs are formed by precipitation reaction. The HAp NPs are dispersed by either citrate or poly(acrylic acid) to form pH sensitive dispersion. Controllable and homogeneous coating of medical implants is accomplished by altering the pH on the surface upon applying either a constant potential or current. The process involves protonation of the carboxylic acid moieties, which causes the irreversible aggregation of the HAp NPs due to diminishing the repulsive forces between the particles. Deposition is further demonstrated on a commercial dental implant. Moreover, the adhesion of the coating satisfies FDA and international standard requirements. A porous interconnected network of bone-like HAp layer is formed during soaking in a simulated body fluid for 30 d and is similar to bone generation, and it therefore holds promise for further in vivo testing.Electrochemical deposition of hydroxyapatite nanoparticles (NPs) is developed for biomedical applications. This unique method is based on oxidation of water, which leads to precipitation of hydroxyapatite (HAp) NPs by protonating the carboxylic group of the dispersing agents. As it is a simple, straightforward, and low-cost method, this technique may be well-suited for industrial use.
      PubDate: 2016-09-20T06:20:43.033834-05:
      DOI: 10.1002/adfm.201603575
  • Coulomb Enhanced Charge Transport in Semicrystalline Polymer
    • Authors: Riccardo Di Pietro; Iyad Nasrallah, Joshua Carpenter, Eliot Gann, Lisa Sophie Kölln, Lars Thomsen, Deepak Venkateshvaran, Kathryn O'Hara, Aditya Sadhanala, Michael Chabinyc, Christopher R. McNeill, Antonio Facchetti, Harald Ade, Henning Sirringhaus, Dieter Neher
      Pages: 8011 - 8022
      Abstract: Polymer semiconductors provide unique possibilities and flexibility in tailoring their optoelectronic properties to match specific application demands. The recent development of semicrystalline polymers with strongly improved charge transport properties forces a review of the current understanding of the charge transport mechanisms and how they relate to the polymer's chemical and structural properties. Here, the charge density dependence of field effect mobility in semicrystalline polymer semiconductors is studied. A simultaneous increase in mobility and its charge density dependence, directly correlated to the increase in average crystallite size of the polymer film, is observed. Further evidence from charge accumulation spectroscopy shows that charges accumulate in the crystalline regions of the polymer film and that the increase in crystallite size affects the average electronic orbitals delocalization. These results clearly point to an effect that is not caused by energetic disorder. It is instead shown that the inclusion of short range coulomb repulsion between charge carriers on nanoscale crystalline domains allows describing the observed mobility dependence in agreement with the structural and optical characterization. The conclusions that are extracted extend beyond pure transistor characterization and can provide new insights into charge carrier transport for regimes and timescales that are relevant to other optoelectronic devices.The charge density dependence of the charge carrier mobility in semicrystalline polymers is shown to be directly correlated to the increase in crystallite size in the polymer film. The effect is not caused by energetic disorder and can be explained if the morphology of semicrystalline polymers and the effect of electron electron interaction is explicitly taken into account.
      PubDate: 2016-09-20T08:40:27.660004-05:
      DOI: 10.1002/adfm.201602080
  • Size-Selective Binding of Sodium and Potassium Ions in Nanoporous Thin
           Films of Polymerized Liquid Crystals
    • Authors: Gerardus M. Bögels; Jody A. M. Lugger, Olga J. G. M. Goor, Rint P. Sijbesma
      Pages: 8023 - 8030
      Abstract: The development of a nanoporous material from a columnar liquid crystalline complex between a polymerizable benzoic acid derivative and a 1,3,5-tris(1H-benzo[d]imidazol-2-yl)benzene template molecule is described. The morphology of the liquid crystalline complex is retained upon polymerization and quantitative removal of the template molecule affords a nanoporous material with the same lattice parameters. The nanoporous material selectively binds cations from aqueous solution, with selectivity for sodium and potassium ions over lithium and barium ions, as shown with FT-IR. Binding is also quantified gravimetrically with a quartz crystal microbalance with dissipation monitoring, a technique that is used for this purpose for the first time here.A nanoporous material was developed by the self-assembly and cross-linking of a hydrogen-bonded columnar liquid crystalline complex. Subsequent quantitative removal of the template affords the nanoporous material that size-selectively binds sodium and potassium ions over other ions. This is analyzed for the first time by utilizing the quartz crystal microbalance.
      PubDate: 2016-09-28T06:13:41.130547-05:
      DOI: 10.1002/adfm.201603408
  • Hyperspectral Imaging Offers Visual and Quantitative Evidence of Drug
           Release from Zwitterionic-Phospholipid-Nanocarbon When Concurrently
           Tracked in 3D Intracellular Space
    • Authors: Santosh K. Misra; Fatemeh Ostadhossein, Enrique Daza, Elyse V. Johnson, Dipanjan Pan
      Pages: 8031 - 8041
      Abstract: Spatial and spectral information of a nanocarrier and its payload is crucial for the advancement of luminescence-based imaging, disease detection, and treatment in complex biological environment. However, it remains challenging to track and quantify the delivery and localization of drugs lacking inherent fluorescence. It is demonstrated that sub 30 nm phospholipid-stabilized nanoparticles can be detected and quantified using hyperspectral transmitted light microscopy without using a fluorophore. In two proposed model systems, phospholipid-passivated carbon nanoparticles incorporate the drug in either free form or as a lipid-based prodrug. Following a rigorous characterization of these nanoparticles, in vitro toxicities via loss in cell growth density and mitochondrial respiration is studied in MCF-7 breast cancer cells. Furthermore, a detailed inhibitor based study reveals that these particles are internalized based on a clathrin-mediated pathway, irrespective of the choice of drug formulation. Hyperspectral imaging is performed to obtain the colocalization of carbon nanoparticles and drug molecules intracellularly and can successfully be tracked while therapeutic release is quantified in 3D space. The present work demonstrates that nanoparticles and therapeutic agents can be mapped and measured simultaneously barring the requirement of a dye, thus providing new avenues in the spatiotemporal characterization and synchronous detection and quantification of payload and carrier.Hyperspectral mapping of drug-laden phospholipid-nanocarbon offers visual clue of release of drug in vitro and synchronous tracking of nanoformulation in 3D intracellular space.
      PubDate: 2016-09-26T08:31:11.262195-05:
      DOI: 10.1002/adfm.201602966
  • Singlet–Triplet Splitting Energy Management via Acceptor Substitution:
           Complanation Molecular Design for Deep-Blue Thermally Activated Delayed
           Fluorescence Emitters and Organic Light-Emitting Diodes Application
    • Authors: Xinyi Cai; Bin Gao, Xiang-Long Li, Yong Cao, Shi-Jian Su
      Pages: 8042 - 8052
      Abstract: A barely reached balance between weak intramolecular-charge-transfer (ICT) and small singlet–triplet splitting energy (ΔEST) for reverse intersystem crossing from non-emissive triplet state to radiative singlet state impedes the realization of deep-blue thermally activated delayed fluorescence (TADF) materials. By discarding the twisted-ICT framework for a flattened molecular backbone and introducing a strong acceptor possessing n–π* transition character, hypsochromic color, a large radiative rate (kF), and small ΔEST are achieved simultaneously. Six molecules with a 9,9-dimethyl-10-phenyl-9,10-dihydroacridine (i-DMAc) donor are synthesized and investigated. Coinciding with time-dependent density functional theory, the reduced dihedral angles between donor (D) and acceptor (A) weaken ICT from dispersed charge density and enable a large kF from increased frontier molecular orbitals overlap. Despite the separated highest occupied (HOMO) and lowest unoccupied molecular orbital (LUMO) population, the intercalation of phenyl bridges between D–A increases kF but significantly lowers the local triplet excited state, indicating small HOMO and LUMO overlap is not a sufficient, but necessary condition for reduced ΔEST. Integrating short conjugation length and carbonyl or triazine acceptors into the complanation molecules, deep-blue TADF organic light-emitting diodes demonstrate maximum external quantum efficiencies of 11.5% and 10.9% with Commission Internationale de l'Eclairage coordinates of (0.16, 0.09) and (0.15, 0.11), respectively, which is quite close to the stringent National Television System Committee blue standard.Integrating a strong electron-withdrawing acceptor moiety with short conjugation length and n–π* character into a planar molecular backbone is promising for meeting high radiative rate, weak intramolecular charge-transfer state, and small singlet–triplet splitting energy simultaneously. Employing such a strategy, deep-blue organic light emitting diode with external quantum efficiency of 11.5% and Commission Internationale de l'Eclairage coordinates of (0.16, 0.09) is achieved.
      PubDate: 2016-09-28T06:14:08.873262-05:
      DOI: 10.1002/adfm.201603520
  • Tunable Nanoparticle and Cell Assembly Using Combined Self-Powered
           Microfluidics and Microcontact Printing
    • Authors: Cyrille Hamon; Malou Henriksen-Lacey, Andrea La Porta, Melania Rosique, Judith Langer, Leonardo Scarabelli, Ana Belén Serrano Montes, Guillermo González-Rubio, Marian M. de Pancorbo, Luis M. Liz-Marzán, Lourdes Basabe-Desmonts
      Pages: 8053 - 8061
      Abstract: The combination of cell microenvironment control and real-time monitoring of cell signaling events can provide key biological information. Through precise multipatterning of gold nanoparticles (GNPs) around cells, sensing and actuating elements can be introduced in the cells' microenviroment, providing a powerful substrate for cell studies. In this work, a combination of techniques are implemented to engineer complex substrates for cell studies. Alternating GNPs and bioactive areas are created with micrometer separation by means of a combination of vacumm soft-lithography of GNPs and protein microcontract printing. Instead of conventional microfluidics that need syringe pumps to flow liquid in the microchannels, degas driven flow is used to fill dead-end channels with GNP solutions, rendering the fabrication process straightforward and accessible. This new combined technique is called Printing and Vacuum lithography (PnV lithography). By using different GNPs with various organic coating ligands, different macroscale patterns are obtained, such as wires, supercrystals, and uniformly spread nanoparticle layers that can find different applications depending on the need of the user. The application of the system is tested to pattern a range of mammalian cell lines and obtain readouts on cell viability, cell morphology, and the presence of cell adhesive proteins.Multipatterns of gold nanoparticles and proteins are simultaneously prepared on a large scale using Printing and Vacuum Lithography to direct cell adhesion on a substrate and to control the cell microenvironment by modulating the gold assemblies' properties as well as the cell-substrate affinity. The application of the system to pattern a range of mammalian cell lines is tested, and readouts on cell viability and cell morphology are obtained.
      PubDate: 2016-09-28T06:14:03.80528-05:0
      DOI: 10.1002/adfm.201602225
  • Size Effects of Platinum Nanoparticles in the Photocatalytic Hydrogen
           Production Over 3D Mesoporous Networks of CdS and Pt Nanojunctions
    • Authors: Ioannis Vamvasakis; Bin Liu, Gerasimos S. Armatas
      Pages: 8062 - 8071
      Abstract: Catalysts for the photogeneration of hydrogen from water are key for realizing solar energy conversion. Despite tremendous efforts, developing hydrogen evolution catalysts with high activity and long-term stability remains a daunting challenge. Herein, the design and fabrication of mesoporous Pt-decorated CdS nanocrystal assemblies (NCAs) are reported, and their excellent performance for the photocatalytic hydrogen production is demonstrated. These materials comprise varying particle size of Pt (ranging from 1.8 to 3.3 nm) and exhibit 3D nanoscale pore structure within the assembled network. Photocatalytic measurements coupled with UV–vis/NIR optical absorption, photoluminescence, and electrochemical impedance spectroscopy studies suggest that the performance enhancement of these catalytic systems arises from the efficient hole transport at the CdS/electrolyte interface and interparticle Pt/CdS electron-transfer process as a result of the deposition of Pt. It is found that the Pt-CdS NCAs catalyst at 5 wt% Pt loading content exerts a 1.2 mmol h−1 H2-evolution rate under visible-light irradiation (λ ≥ 420 nm) with an apparent quantum yield of over 70% at wavelength λ = 420 nm in alkaline solution (5 m NaOH), using ethanol (10% v/v) as sacrificial agent. This activity far exceeds those of the single CdS and binary noble metal/CdS systems, demonstrating the potential for practical photocatalytic hydrogen production.3D mesoporous architectures of CdS and Pt nanocrystals are demonstrated as highly effective catalysts for the hydrogen evolution reaction (HER). Photocatalytic measurements coupled with spectroscopic studies suggest that deposition of ultrasmall Pt nanoparticles enhances the HER activity because of variations in the band-edge positions and electron donor density of CdS nanocrystals.
      PubDate: 2016-09-26T08:30:43.149252-05:
      DOI: 10.1002/adfm.201603292
  • Immune Complexes Mimicking Synthetic Vaccine Nanoparticles for Enhanced
           Migration and Cross-Presentation of Dendritic Cells
    • Authors: Sun-Young Kim; Hathaichanok Phuengkham, Young-Woock Noh, Hong-Guen Lee, Soong Ho Um, Yong Taik Lim
      Pages: 8072 - 8082
      Abstract: The well-designed activation of dendritic cells (DCs) by enhancing the delivery of antigens and immunostimulatory adjuvants into DCs is a key strategy for efficient cancer immunotherapy. Antigen-antibody immune complexes (ICs) are known to directly bind to and cross-link Fc-gamma receptors (FcγRs) on DCs, which induce enhanced migration of DCs to draining lymph nodes through the up-regulation of the chemokine receptor CCR7 and cross-presentation inducing cytotoxic T lymphocyte (CTL) response against tumor antigen. In this study, ICs mimicking synthetic vaccine nanoparticles (NPs) are designed and synthesized by the coating of poly (lactic-co-glycolic acid) (PLGA) NPs containing adjuvant (CpG oligodeoxynuleotides (ODNs) as toll-like receptor 9 ligands) with ovalbumin (OVA) proteins (as model antigens) and by the formation of OVA–OVA antibody ICs. Through the combination of FcγRs-mediated efficient antigen uptake and CpG ODNs-based immunostimulation, the secretion of TNF-α (12.3-fold), IL-6 (7.29-fold), and IL-12 (11-fold), homing ability to lymph nodes (7.5-fold), and cross-presentation (83.8-fold IL-2 secretion) are dramatically increased in DCs treated with PLGA(IC/CpG) NPs. Furthermore, mice vaccinated with DCs treated with PLGA(IC/CpG) NPs induced significant tumor (EG7-OVA) growth inhibition as well as prolonged survival through CTL-mediated enhanced cytotoxicity, antigen-specific responses, and IFN-γ secretion.Antigen-antibody immune complexes (ICs) mimicking synthetic vaccine nanoparticles for activation of dendritic cells for antigen-specific adaptive immunity are designed. Mice immunized with dendritic cells treated with ICs mimicking synthetic vaccine nanoparticles induce significant tumor growth inhibition as well as prolonged survival through cytotoxic T lymphocyte response.
      PubDate: 2016-09-27T01:24:21.244862-05:
      DOI: 10.1002/adfm.201603651
  • Novel Cathode Materials for Na-Ion Batteries Composed of Spoke-Like
           Nanorods of Na[Ni0.61Co0.12Mn0.27]O2 Assembled in Spherical Secondary
    • Authors: Jang-Yeon Hwang; Seung-Taek Myung, Chong Seung Yoon, Sung-Soo Kim, Doron Aurbach, Yang-Kook Sun
      Pages: 8083 - 8093
      Abstract: The development of high-energy and high-power density sodium-ion batteries is a great challenge for modern electrochemistry. The main hurdle to wide acceptance of sodium-ion batteries lies in identifying and developing suitable new electrode materials. This study presents a composition-graded cathode with average composition Na[Ni0.61Co0.12Mn0.27]O2, which exhibits excellent performance and stability. In addition to the concentration gradients of the transition metal ions, the cathode is composed of spoke-like nanorods assembled into a spherical superstructure. Individual nanorod particles also possess strong crystallographic texture with respect to the center of the spherical particle. Such morphology allows the spoke-like nanorods to assemble into a compact structure that minimizes its porosity and maximizes its mechanical strength while facilitating Na+-ion transport into the particle interior. Microcompression tests have explicitly verified the mechanical robustness of the composition-graded cathode and single particle electrochemical measurements have demonstrated the electrochemical stability during Na+-ion insertion and extraction at high rates. These structural and morphological features contribute to the delivery of high discharge capacities of 160 mAh (g oxide)−1 at 15 mA g−1 (0.1 C rate) and 130 mAh g−1 at 1500 mA g−1 (10 C rate). The work is a pronounced step forward in the development of new Na ion insertion cathodes with a concentration gradient.The tailored microstructural design of spoke-like nanorods assemblies and their unique chemical composition contribute to high capacity, excellent rate capability, and low temperature performance due to their superior mechanical strength during Na+ ion insertion and extraction even at high rates. Furthermore, this unique particle morphology guarantees high thermal stability in the desodiated state of electrodes materials.
      PubDate: 2016-09-27T06:30:53.437903-05:
      DOI: 10.1002/adfm.201603439
  • The Effect of the Microstructure on Trap-Assisted Recombination and Light
           Soaking Phenomenon in Hybrid Perovskite Solar Cells
    • Authors: Shuyan Shao; Mustapha Abdu-Aguye, Tejas S. Sherkar, Hong-Hua Fang, Sampson Adjokatse, Gert ten Brink, Bart J. Kooi, L. Jan Anton Koster, Maria Antonietta Loi
      Pages: 8094 - 8102
      Abstract: Despite the rich experience gained in controlling the microstructure of perovskite films over the past several years, little is known about how the microstructure affects the device properties of perovskite solar cells (HPSCs). In this work, the effects of the perovskite film microstructure on the charge recombination and light-soaking phenomenon in mixed halide HPSCs are investigated. Devices with noncompact perovskite morphology show a severe light soaking effect, with the power conversion efficiency (PCE) improved from 3.7% to 11.6% after light soaking. Devices with compact perovskite morphology show a negligible light soaking effect, with PCE slightly increased from 11.4% to 11.9% after light soaking. From device investigations, photoluminescence, and impedance spectroscopy measurements, it is demonstrated that interface electron traps at the grain boundaries as well as at the crystal surface dominate the light soaking effect. Severe trap-assisted recombination takes place in HPSCs using noncompact films, while it is effectively eliminated in devices with compact films. Moreover, how the grain size of the perovskite film affects the light soaking phenomenon is investigated. In the case of compact perovskite films, the size of the grains has a limited effect on the light soaking. In these compact films, grains are fused and trap states are effectively reduced.The effects of the perovskite film microstructure on the charge recombination and light-soaking phenomenon are investigated in hybrid perovskite solar cells (HPSCs). It is demonstrated that interface electron traps at the grain boundaries as well as at the crystal surface dominate the light soaking effect.
      PubDate: 2016-10-04T08:40:43.85132-05:0
      DOI: 10.1002/adfm.201602519
  • Electrochemical Intercalation of Potassium into Graphite
    • Authors: Jin Zhao; Xiaoxi Zou, Yujie Zhu, Yunhua Xu, Chunsheng Wang
      Pages: 8103 - 8110
      Abstract: Exceptional cycling performance of graphite anode in K-ion batteries is demonstrated with a reversible capacity of 246 mAh g–1 and 89% retention of the initial capacity after 200 cycles. Although the graphite anode experiences huge volume change and worse kinetics during K intercalation/deintercalation, the cycling stability delivered in K-ion batteries is comparable to that of Li-ion batteries using the same graphite anode. The combination of excellent electrochemical performance, the abundance and wide availability of K in earth's crust, and the well-developed technology of the graphite anode make the K-ion battery very attractive for offering a low cost battery chemistry for large-scale energy storage applications.Stable potassium-ion batteries using graphite anodes with reversible capacity of 246 mAh g–1 and 89% remains after 200 cycles are demonstrated. In spite of worse kinetics and much larger volume change for K than Li, comparable cycling stability is achieved. This provides a battery chemistry that is compatible with commercial Li-ion batteries using abundant potassium, thus promising low cost for large-scale energy storage.
      PubDate: 2016-09-26T08:46:39.853069-05:
      DOI: 10.1002/adfm.201602248
  • Nanodroplets for Stretchable Superconducting Circuits
    • Authors: Long Ren; Jincheng Zhuang, Gilberto Casillas, Haifeng Feng, Yuqing Liu, Xun Xu, Yundan Liu, Jun Chen, Yi Du, Lei Jiang, Shi Xue Dou
      Pages: 8111 - 8118
      Abstract: The prospective utilization of nanoscale superconductors as micro/nanocoils or circuits with superior current density and no electrical resistance loss in next-generation electronics or electromagnetic equipment represents a fascinating opportunity for new microsystem technologies. Here, a family of superconducting liquid metals (Ga–In–Sn alloys) and their nanodroplets toward printable and stretchable superconducting micro/nanoelectronics is developed. By tuning the composition of liquid metals the highest superconducting critical temperature (Tc) in this family can be modulated and achieved as high as 6.6 K. The liquid metal nanodroplets retain their bulk superconducting properties and can be easily dispersed in different solvents as inks. The printable and stretchable superconducting micro/nano coils, circuits and electrodes have been fabricated by inkjet printer or laser etching by using superconducting nanodroplets inks. This novel superconducting system greatly promotes the commercial utilization of superconductors into advanced flexible micro/nanoelectronic devices and offers a new platform for developing more application with superconductors.Superconducting eutectic gallium–indium–tin (EGaInSn) alloys and their nanosized droplets with different weight ratios are developed for realizing printable and stretchable superconducting circuits. The highest superconducting critical temperature of EGaInSn is 6.6 K. The corresponding EGaInSn nanodroplets retain the bulk superconducting properties. Their dispersion in various solvents shows excellent wettability, which can be easily applied to print stretchable superconductive micro/nanoelectronics.
      PubDate: 2016-09-26T08:30:49.94031-05:0
      DOI: 10.1002/adfm.201603427
  • Synergistic Effect of PbI2 Passivation and Chlorine Inclusion Yielding
           High Open-Circuit Voltage Exceeding 1.15 V in Both Mesoscopic and Inverted
           Planar CH3NH3PbI3(Cl)-Based Perovskite Solar Cells
    • Authors: Fangyuan Jiang; Yaoguang Rong, Huawei Liu, Tiefeng Liu, Lin Mao, Wei Meng, Fei Qin, Youyu Jiang, Bangwu Luo, Sixing Xiong, Jinhui Tong, Yun Liu, Zaifang Li, Hongwei Han, Yinhua Zhou
      Pages: 8119 - 8127
      Abstract: Enhancing open-circuit voltage in CH3NH3PbI3(Cl) perovskite solar cells has become a major challenge for approaching the theoretical limit of the power conversion efficiency. Here, for the first time, it is demonstrated that the synergistic effect of PbI2 passivation and chlorine incorporation via controlling the molar ratio of PbI2, PbCl2 (or MACl), and MAI in the precursor solutions, boosts the open-circuit voltage of CH3NH3PbI3(Cl) perovskite solar cells over 1.15 V in both mesoscopic and inverted planar perovskite solar cells. Such high open-circuit voltage can be attributed to the enhanced photoluminescence emission and carrier lifetime associated with the reduced trap densities. The morphology and composition analysis using scanning electron microscopy, X-ray diffraction measurements, and energy dispersive X-ray spectroscopy confirm the high quality of the optimized CH3NH3PbI3(Cl) perovskite film. On this basis, record-high efficiencies of 16.6% for nonmetal-electrode all-solution-processed perovskite solar cells and 18.4% for inverted planar perovskite solar cells are achieved.A synergistic effect of PbI2 passivation and chlorine incorporation induces suppression of non-radiative recombination in a perovskite film. This leads to a high open-circuit voltage exceeding 1.15 V in both mesoscopic and inverted planar CH3NH3PbI3(Cl)-based perovskite solar cells.
      PubDate: 2016-09-26T08:31:21.929891-05:
      DOI: 10.1002/adfm.201603968
  • Development of a Unique Class of Spiro-Type Two-Photon Functional
           Fluorescent Dyes and Their Applications for Sensing and Bioimaging
    • Authors: Hua Chen; Huiming Shang, Yong Liu, Rui Guo, Weiying Lin
      Pages: 8128 - 8136
      Abstract: Spiro compounds with rigid structures have attracted significant attention in the recent years due to their useful applications in diverse fields such as asymmetric catalysis and organic optoelectronic materials. However, spiro cores have not yet been employed as the spiro-type two-photon fluorescent dyes in the aspects of sensing and bioimaging. Therefore, the spiro-type two-photon fluorescent dyes with excellent two-photon properties are highly sought after. Here, a unique class of spiro-type two-photon fluorescent dyes (STP) is engineered and applied in sensing and bioimaging. The studies indicate that the novel STP fluorescent dyes have favorable two-photon properties from the point view of spiro compounds. By exploiting the superior two-photon optical properties of the STP dyes, the first two-photon ratiometric HOCl fluorescent probe STP-HClO for sensing and imaging HOCl in the living cells and living tissues is constructed, demonstrating the profound value of the new STP dyes for the unprecedented development of the sprio-type fluorescent sensing and imaging agents. It is believed that the innovative STP dyes may pave the way for designing more efficient spiro-type two-photon fluorescent probes and organic optoelectronic materials as well.A unique class of spiro-type two-photon fluorescent dyes (STP) is engineered and applied in sensing and bioimaging for the first time. By exploiting the superior two-photon optical properties of the novel STP dyes, the first two-photon ratiometric HOCl fluorescent probe STP-HClO for sensing and imaging HOCl in living cells and tissues is constructed.
      PubDate: 2016-10-04T03:16:24.56822-05:0
      DOI: 10.1002/adfm.201603495
  • Facile Fabrication of High-Density Sub-1-nm Gaps from Au Nanoparticle
           Monolayers as Reproducible SERS Substrates
    • Authors: Shaorong Si; Wenkai Liang, Yinghui Sun, Jing Huang, Weiliang Ma, Zhiqiang Liang, Qiaoliang Bao, Lin Jiang
      Pages: 8137 - 8145
      Abstract: The fabrication of ultrasmall nanogaps (sub-1 nm) with high density is of significant interest and importance in physics, chemistry, life science, materials science, surface science, nanotechnology, and environmental engineering. However, it remains a challenge to generate uncovered and clean sub-1-nm gaps with high density and uniform reproducibility. Here, a facile and low-cost approach is demonstrated for the fabrication of high-density sub-1-nm gaps from Au nanoparticle monolayers as reproducible surface-enhanced Raman scattering (SERS) substrates. Au nanoparticles with larger diameters possess lower surface charge, thus the obtained large-area nanoparticle monolayer generates a high-density of sub-1-nm gaps. In addition, a remarkable SERS performance with a 1011 magnitude for the Raman enhancement is achieved for 120 nm Au nanoparticle monolayers due to the dramatic increase in the electromagnetic field enhancement when the obtained gap is smaller than 0.5 nm. The Au nanoparticle monolayer is also transferred onto a stretchable PDMS substrate and the structural stability and reproducibility of the high-density sub-1-nm gaps in Au monolayer films are illustrated. The resultant Au nanoparticle monolayer substrates with an increasing particle diameter exhibit tunable plasmonic properties, which control the plasmon-enhanced photocatalytic efficiency for the dimerization of p-aminothiophenol. The findings reported here offer a new opportunity for expanding the SERS application.A facile and low-cost approach is demonstrated for the fabrication of high-density sub-1-nm gaps from Au nanoparticle monolayers as reproducible surface-enhanced Raman scattering (SERS) substrates. Remarkable SERS performance with a 1011 magnitude Raman enhacement is achieved for 120 nm Au nanoparticle monolayers due to the dramatic increase in the electromagnetic field enhancement when the obtained gap is smaller than 0.5 nm.
      PubDate: 2016-10-06T07:01:12.158384-05:
      DOI: 10.1002/adfm.201602337
  • Carbon Nanodots: Assigning Electronic States in Carbon Nanodots (Adv.
           Funct. Mater. 44/2016)
    • Authors: Volker Strauss; Axel Kahnt, Eva M. Zolnhofer, Karsten Meyer, Harald Maid, Christian Placht, Walter Bauer, Thomas J. Nacken, Wolfgang Peukert, Sebastian H. Etschel, Marcus Halik, Dirk M. Guldi
      Pages: 8147 - 8147
      Abstract: Pressure synthesized carbon nanodots are investigated by the multidisciplinary team of D. M. Guldi and co-workers on page 7975. The cover illustrates the reductive or oxidative charging of the carbon nanodots (pCNDs) at electrode surfaces. The relation between the dot's surface states and their optical features is revealed to be fairly complex. Future work should address the transformation of functional groups upon oxidation or reduction.
      PubDate: 2016-11-21T07:56:13.135882-05:
      DOI: 10.1002/adfm.201670291
  • Directional Motion: Electric Field and Gradient Microstructure for
           Cooperative Driving of Directional Motion of Underwater Oil Droplets (Adv.
           Funct. Mater. 44/2016)
    • Authors: Dongliang Tian; Linlin He, Na Zhang, Xi Zheng, Yuhai Dou, Xiaofang Zhang, Zhenyan Guo, Lei Jiang
      Pages: 8148 - 8148
      Abstract: On page 7986, D. Tian, X. Zhang, Z. Guo, and co-workers demonstrate the directional motion of underwater oil droplets driven by the cooperative effects of an electric field and a gradient-structured porous PS film. The approach is promising for the design of new smart interface materials for applications in electrofluidic displays, biological cells, and particle manipulation.
      PubDate: 2016-11-21T07:56:12.082584-05:
      DOI: 10.1002/adfm.201670292
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