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  Subjects -> CHEMISTRY (Total: 852 journals)
    - ANALYTICAL CHEMISTRY (52 journals)
    - CHEMISTRY (598 journals)
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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 10)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 38)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 24)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 252)
ACS Photonics     Full-text available via subscription   (Followers: 12)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 23)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chimica Slovenica     Open Access  
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 8)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 51)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 57)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 15)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 21)
Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 66)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 15)
American Journal of Chemistry     Open Access   (Followers: 27)
American Journal of Plant Physiology     Open Access   (Followers: 14)
American Mineralogist     Hybrid Journal   (Followers: 14)
Analyst     Full-text available via subscription   (Followers: 39)
Angewandte Chemie     Hybrid Journal   (Followers: 179)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 231)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 16)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal   (Followers: 1)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 22)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 324)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 120)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 84)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 68)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 7)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 8)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 15)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 25)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 21)
Chemical Reviews     Full-text available via subscription   (Followers: 185)
Chemical Science     Open Access   (Followers: 22)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 147)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 20)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 42)
Chemistry of Materials     Full-text available via subscription   (Followers: 250)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 4)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 10)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 19)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 3)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 18)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 64)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 3)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  

        1 2 3 | Last

Journal Cover Advanced Functional Materials
  [SJR: 5.21]   [H-I: 203]   [51 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1616-301X - ISSN (Online) 1616-3028
   Published by John Wiley and Sons Homepage  [1589 journals]
  • High Lithium Ion Conductivity LiF/GO Solid Electrolyte Interphase
           Inhibiting the Shuttle of Lithium Polysulfides in Long-Life Li–S
           Batteries
    • Authors: Xuyan Ni; Tao Qian, Xuejun Liu, Na Xu, Jie Liu, Chenglin Yan
      Abstract: The “shuttle effect” that stems from the dissolution of polysulfides is the most fatal issue affecting the cycle life of lithium-sulfur (Li–S) batteries. In order to suppress the “shuttle effect,” a new strategy of using a highly lithium ion conductive lithium fluoride/graphene oxide (LiF/GO) solid electrolyte interphase (SEI) to mechanically prevent the lithium dendrite breakthrough is reported. When utilized in Li–S batteries, the LiF/GO SEI coated separator demonstrates significant feature in mitigating the polysulfide shuttling as observed by in situ UV–vis spectroscopy. Moreover, the restrained “shuttle effect” can also be confirmed by analysis of electrochemical impedance spectroscopy and characterization of lithium dendrites, which indicates that no insulating layer of solid Li2S2/Li2S is found on lithium anode surface. Furthermore, the LiF/GO SEI layer puts out good lithium ion conductivity as its lithium ion diffusion coefficient reaches a high value of 1.5 × 10−7 cm2 s−1. These features enable a remarkable cyclic property of 0.043% of capacity decay per cycle during 400 cycles.A high lithium ion conductivity LiF/GO solid electrolyte interphase coated separator is developed to block the diffusion of polysulfides for long-life Li–S batteries. The “shuttle effect” is greatly suppressed as confirmed by in situ experimental results and electrochemical impedance spectroscopy analysis. The assembled Li–S batteries with such a separator exhibit only 0.043% of capacity decay per cycle during 400 cycles.
      PubDate: 2018-01-18T05:51:54.735937-05:
      DOI: 10.1002/adfm.201706513
       
  • Tunable Electrochemistry of Electrosynthesized Copper Metal–Organic
           Frameworks
    • Authors: Liudi Ji; Juan Wang, Kangbing Wu, Nianjun Yang
      Abstract: Metal–organic frameworks (MOFs) synthesized using different organic ligands are expected to have varied morphology and properties. Herein, three copper MOFs (Cu-MOFs) are electrosynthesized using a simple and direct reduction approach and three organic ligands: 1,3,5-benzenetricarboxylic acid, 1,4-benzenedicarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid. The as-synthesized Cu-MOFs exhibit varied morphology. Their electrochemistry is further explored via investigating the natures of their capacitive, faradaic, and electrocatalytic behavior. The stability of these Cu-MOFs is also checked during the course of electrochemical measurements. The secondary built units of organic ligands with copper ions are found theoretically and experimentally to determine both the morphology and active sites of Cu-MOFs. Namely the electrochemistry of Cu-MOFs is dependent on the used organic ligands. Cu-MOF synthesized using 1,3,5-benzenetricarboxylic acid owns better electrochemistry than that using 1,4-benzenedicarboxylic acid or 1,2,4,5-benzenetetracarboxylic acid. These MOFs keep their compositions and crystallinity unchanged in short times but loss them for long electrochemical running times. Therefore, the properties and applications of MOFs are designable and can be optimized during the course of reduction electrosynthesis processes via selecting organic ligands and metal ions.Copper metal–organic frameworks, electrosynthesized using a reductive approach and different organic ligands, exhibit different morphology and electrochemical properties (e.g., capacitive, faradaic, and electrocatalytic behavior). The second building units from organic ligands and copper metal ions actually determine these properties.
      PubDate: 2018-01-18T05:51:25.406539-05:
      DOI: 10.1002/adfm.201706961
       
  • Facile Nondestructive Assembly of Tyrosine-Rich Peptide Nanofibers as a
           Biological Glue for Multicomponent-Based Nanoelectrode Applications
    • Authors: Kyoung-Ik Min; Seung-Woo Lee, Eun-Hee Lee, Yoon-Sik Lee, Hyunjung Yi, Dong-Pyo Kim
      Abstract: Achieving the nondestructive assembly of carbon nanoelectrodes with multiple components in a scalable manner enables effective electrical interfaces among nanomaterials. Here, a facile nondestructive multiscale assembly of multicomponent nanomaterials using self-assembled tyrosine-rich peptide nanofibers (TPFs) as a biological glue is reported. The versatile functionalities of the rationally devised tyrosine-rich short peptide allow for (1) self-assembly of the peptide into nanofibers using noncovalent interactions, followed by (2) immobilization of spatially distributed metal nanoparticles on the nanofiber surface, and (3) subsequent assembly with graphitic nanomaterials into a percolated network-structure. This percolated network-structure of silver nanoparticle (AgNP)-decorated peptide nanofibers with imbedded single-walled carbon nanotubes (SWNTs) proves to be a versatile nanoelectrode platform with excellent processability. The SWNT–TPF–AgNP assembly, when utilized as a flexible and transparent multicomponent electronic film, was quite effective for enhancing direct electron transfer (DET) as verified for a third-generation glucose sensor composed of this film. The simple solution process used to produce the functional nanomaterials could provide a new platform for scalable manufacturing of novel nanoelectrode materials forming effective electrical contacts with molecules from diverse biological systems.Multiscale assembly of multicomponent nanomaterials is achieved by using self-assembled tyrosine-rich peptide nanofibers as a biological glue. These peptide nanofibers decorated with silver nanoparticles and imbedded with graphitic nanomaterials prove to be a versatile nanoelectrode platform for efficient electrical contact with biological molecules, as verified by efficient direct electron transfer achieved for a glucose sensor.
      PubDate: 2018-01-18T05:36:49.483902-05:
      DOI: 10.1002/adfm.201705729
       
  • Degenerately Hydrogen Doped Molybdenum Oxide Nanodisks for Ultrasensitive
           Plasmonic Biosensing
    • Authors: Bao Yue Zhang; Ali Zavabeti, Adam F. Chrimes, Farjana Haque, Luke A. O'Dell, Hareem Khan, Nitu Syed, Robi Datta, Yichao Wang, Anthony S. R. Chesman, Torben Daeneke, Kourosh Kalantar-zadeh, Jian Zhen Ou
      Abstract: Plasmonic biosensors based on noble metals generally suffer from low sensitivities if the perturbation of refractive-index in the ambient is not significant. By contrast, the features of degenerately doped semiconductors offer new dimensions for plasmonic biosensing, by allowing charge-based detection. Here, this concept is demonstrated in plasmonic hydrogen doped molybdenum oxides (HxMoO3), with the morphology of 2D nanodisks, using a representative enzymatic glucose sensing model. Based on the ultrahigh capacity of the molybdenum oxide nanodisks for accommodating H+, the plasmon resonance wavelengths of HxMoO3 are shifted into visible-near-infrared wavelengths. These plasmonic features alter significantly as a function of the intercalated H+ concentration. The facile H+ deintercalation out of HxMoO3 provides an exceptional sensitivity and fast kinetics to charge perturbations during enzymatic oxidation. The optimum sensing response is found at H1.55MoO3, achieving a detection limit of 2 × 10−9m at 410 nm, even when the biosensing platform is adapted into a light-emitting diode-photodetector setup. The performance is superior in comparison to all previously reported plasmonic enzymatic glucose sensors, providing a great opportunity in developing high performance biosensors.HxMoO3 plasmonic disks are synthesized. H+ and concurrently electrons can be extracted from the host structure during a designed biochemical event. This alteration in charge rapidly changes the plasmon resonance features, hence creating an ultrasensitive platform.
      PubDate: 2018-01-18T05:32:11.760983-05:
      DOI: 10.1002/adfm.201706006
       
  • Low-Bandgap Methylammonium-Rubidium Cation Sn-Rich Perovskites for
           Efficient Ultraviolet–Visible–Near Infrared Photodetectors
    • Authors: Hugh Lu Zhu; Zhifu Liang, Zhengbao Huo, Wai Kit Ng, Jian Mao, Kam Sing Wong, Wan-Jian Yin, Wallace C. H. Choy
      Abstract: Solution-processed and low-temperature Sn-rich perovskites show their low bandgap of about 1.2 eV, enabling potential applications in next-generation cost-effective ultraviolet (UV)–visible (vis)–near infrared (NIR) photodetection. Particularly, the crystallization (crystallinity and orientation) and film (smooth and dense film) properties of Sn-rich perovskites are critical for efficient photodetectors, but are limitedly studied. Here, controllable crystallization for growing high-quality films with the improvements of increased crystallinity and strengthened preferred orientation through a introducing rubidium cation into the methylammonium Sn-Pb perovskite system (65% Sn) is achieved. Fundamentally, the theoretical results show that rubidium incorporation causes lower surface energy of (110) plane, facilitating growth in the dominating plane and suppressing growth of other competing planes. Consequently, the methylammonium-rubidium Sn-Pb perovskite photodetectors simultaneously achieve larger photocurrent and lower noise current. Finally, highly efficient UV–vis–NIR (300–1100 nm) photodetectors with record-high linear dynamic range of 110 and 3 dB cut-off frequency reaching 1 MHz are demonstrated. This work contributes to enriching the cation selection in Sn-Pb perovskite systems and offering a promising candidate for low-cost UV–vis–NIR photodetection.Controllable crystallization for growing high-quality films with increased crystallinity and strengthened preferred orientation is achieved through introducing rubidium cation into the methylammonium Sn-Pb perovskite system. Methylammonium-rubidium Sn-rich perovskite-photodetectors simultaneously achieve larger photocurrent and lower noise current. Highly efficient UV–vis-near infrared (300–1100 nm) photodetectors with record-high linear dynamic range of 110 and 3 dB cut-off frequency reaching 1 MHz are demonstrated.
      PubDate: 2018-01-18T05:31:33.151997-05:
      DOI: 10.1002/adfm.201706068
       
  • Dependence of Photocurrent Enhancements in Quantum Dot (QD)-Sensitized
           MoS2 Devices on MoS2 Film Properties
    • Authors: John J. Gough; Niall McEvoy, Maria O'Brien, Alan P. Bell, David McCloskey, John B. Boland, Jonathan N. Coleman, Georg S. Duesberg, A. Louise Bradley
      Abstract: This report demonstrates highly efficient nonradiative energy transfer (NRET) from alloyed CdSeS/ZnS semiconductor nanocrystal quantum dots (QDs) to MoS2 films of varying layer thicknesses, including pristine monolayers, mixed monolayer/bilayer, polycrystalline bilayers, and bulk-like thicknesses, with NRET efficiencies of over 90%. Large-area MoS2 films are grown on Si/SiO2 substrates by chemical vapor deposition. Despite the ultrahigh NRET efficiencies there is no distinct increase in the MoS2 photoluminescence intensity. However, by studying the optoelectronic properties of the MoS2 devices before and after adding the QD sensitizing layer photocurrent enhancements as large as ≈14-fold for pristine monolayer devices are observed, with enhancements on the order of ≈2-fold for MoS2 devices of mixed monolayer and bilayer thicknesses. For the polycrystalline bilayer and bulk-like MoS2 devices there is almost no increase in the photocurrent after adding the QDs. Industrially scalable techniques are specifically utilized to fabricate the samples studied in this report, demonstrating the viability of this hybrid structure for commercial photodetector or light harvesting applications.The importance of crystalline monolayers in quantum dot sensitized MoS2 devices is demonstrated. Nonradiative energy transfer from semiconductor nanocrystal quantum dots to a variety of MoS2 devices is studied. The MoS2 devices consist of varying layer thickness and crystalline properties, including pristine monolayers, mixed monolayer/bilayer, polycrystalline bilayers, and bulk-like thicknesses. Large photocurrent enhancements require crystalline MoS2 monolayers.
      PubDate: 2018-01-18T05:31:12.103786-05:
      DOI: 10.1002/adfm.201706149
       
  • Versatile, High-Power, Flexible, Stretchable Carbon Nanotube Sheet Heating
           Elements Tolerant to Mechanical Damage and Severe Deformation
    • Authors: Yourack Lee; Viet Thong Le, Jeong-Gyun Kim, Haeyong Kang, Eun Sung Kim, Seung-Eon Ahn, Dongseok Suh
      Abstract: A macroscopic carbon nanotube (CNT) sheet-based heating element having flexible, stretchable, and damage-tolerant features, and wide applicability in harsh environments, is introduced. Because of the intrinsic connection of extremely flexible CNT bundles throughout the sample by van der Waals interactions without use of a binder, the electrical resistance variation of the CNT sheet on elastomer heating element as a function of strain is completely suppressed to some extent, even when stretched under up to 400% strain, which guarantees electrical stability under severe mechanical deformation. In addition, the spatial uniformity of the heat generated from the microaligned CNT bundles reduces the temperature variation inside the sample, which also guarantees thermal stability and operation at a higher average temperature. Such exceptional performance is achieved by the passivation of the elastomer layer on the CNT sheets. Furthermore, the mechanical robustness of this flexible, stretchable heating element is demonstrated by stable heater operation, even when the heating element is damaged. In addition, this design concept of CNT sheet on elastomer is extended to transparent flexible heaters and electric-thermochromic windows.A deformable, stretchable electric heating element is presented. The synergistic combination of aligned carbon nanotube sheets and highly stretchable elastomer results in outstanding flexible heater performance with superior electrical, thermal, and mechanical properties. A carbon nanotube-based array of nanofibrillar heaters on elastomer guarantees spatial uniformity, as well as damage-tolerant mechanical robustness.
      PubDate: 2018-01-18T05:26:44.413395-05:
      DOI: 10.1002/adfm.201706007
       
  • Dual Role of Subphthalocyanine Dyes for Optical Imaging and Therapy of
           Cancer
    • Authors: Eveline Winckel; Marta Mascaraque, Alicia Zamarrón, Ángeles Juarranz de la Fuente, Tomás Torres, Andrés Escosura
      Abstract: The family of subphthalocyanine (SubPc) macrocycles represents an interesting class of nonplanar aromatic dyes with promising features for energy conversion and optoelectronics. The use of SubPcs in biomedical research is, on the contrary, clearly underexplored, despite their documented high fluorescence and singlet oxygen quantum yields. Herein, for the first time it is shown that the interaction of these chromophores with light can also be useful for theranostic applications, which in the case of SubPcs comprise optical imaging and photodynamic therapy (PDT). In particular, the article evaluates, through a complete in vitro study, the dual-role capacity of a novel series of SubPcs as fluorescent probes and PDT agents, where the macrocycle axial substitution determines their biological activity. The 2D and 3D imaging of various cancer cell lines (i.e., HeLa, SCC-13, and A431) has revealed, for example, different subcellular localization of the studied photosensitizers (PS), depending on the axial substituent they bear. These results also show excellent photocytotoxicities, which are affected by the PS localization. With the best dual-role PS, preliminary in vivo studies have demonstrated their therapeutic potential. Overall, the present paper sets the bases for an unprecedented biomedical use of these well-known optoelectronic materials.The dual optical imaging and photodynamic therapy capacity of a series of SubPc photosensitizers bearing different axial substituents is presented for the first time. The influence of the axial substituent on the subcellular localization and cell survival after photodynamic treatment is carefully evaluated using 2D and 3D in vitro tumor models, and a proof of concept of in vivo therapeutic efficacy is established in tumor-bearing mice.
      PubDate: 2018-01-18T05:26:20.075859-05:
      DOI: 10.1002/adfm.201705938
       
  • Highly Porous Polymer Aerogel Film-Based Triboelectric Nanogenerators
    • Authors: Qifeng Zheng; Liming Fang, Haiquan Guo, Kefang Yang, Zhiyong Cai, Mary Ann B. Meador, Shaoqin Gong
      Abstract: A novel class of high performance polymer porous aerogel film-based triboelectric nanogenerators (A-NGs) is demonstrated. The A-NGs, made of a pair of highly porous polymer films, exhibit much higher triboelectric outputs than the corresponding dense polymer film-based triboelectric nanogenerators (D-NGs) under the same mechanical stress. The triboelectric outputs of the A-NGs increase significantly with increasing porosity, which can be attributed to the increase in contact area and the electrostatic induction in the porous structure, thereby leading to additional charges on the porous surface. Remarkably, the A-NG fabricated using porous chitosan aerogel film paired with the most porous polyimide (with a porosity of 92%) aerogel film demonstrates a very high voltage of 60.6 V and current of 7.7 µA, corresponding to a power density of 2.33 W m−2, which is sufficient to power 22 blue light-emitting-diodes (LEDs). This is the first report on triboelectric nanogenerators (TENGs) employing porous polymer aerogel films as both positive and negative materials to enhance triboelectric outputs. Furthermore, enhancing the tribopositive polarity of the cellulose aerogel film via silanization using aminosilane can dramatically improve the triboelectric performance. Therefore, this study provides new insights into investigating porous materials with tunable triboelectric polarities for high performance TENGs.A novel class of high performance triboelectric nanogenerators consisting of a pair of highly porous aerogel polymer films is demonstrated and they exhibit up to 11-fold of power enhancement compared to their corresponding dense-film-based nanogenerators. The output of the nanogenerators increases significantly with increasing porosity of the aerogels which can be further improved via aminosilane functionalization.
      PubDate: 2018-01-18T05:21:49.572977-05:
      DOI: 10.1002/adfm.201706365
       
  • 4D Biofabrication: 3D Cell Patterning Using Shape-Changing Films
    • Authors: Vladislav Stroganov; Jitendra Pant, Georgi Stoychev, Andreas Janke, Dieter Jehnichen, Andreas Fery, Hitesh Handa, Leonid Ionov
      Abstract: A novel approach for fabrication of 3D cellular structures using new thermosensitive shape-changing polymer films with photolithographically patterned surface—4D biofabrication is reported. The surface of shape-changing polymer films is patterned to selectively adsorb cells in specific regions. The 2D cell pattern is converted to the 3D cell structure after temperature-induced folding of the polymer films. This approach has a great potential in the field of tissue engineering and bioscaffolds fabrication.A new way to achieve selective cell adhesion to a surface in 3D space is shown. The material being used is a self-folding thermoresponsive polymer bilayer with patterned surface. Pattern on the surface governs where cells will adhere and thermoinduced folding creates a 3D shape filled with cells.
      PubDate: 2018-01-18T05:21:26.872496-05:
      DOI: 10.1002/adfm.201706248
       
  • Vertex-Reinforced PtCuCo Ternary Nanoframes as Efficient and Stable
           Electrocatalysts for the Oxygen Reduction Reaction and the Methanol
           Oxidation Reaction
    • Authors: Taehyun Kwon; Minki Jun, Ho Young Kim, Aram Oh, Jongsik Park, Hionsuck Baik, Sang Hoon Joo, Kwangyeol Lee
      Abstract: Noble metal binary alloy nanoframes have emerged as a new class of fuel cell electrocatalysts because of their intrinsic high catalytic surface area and accompanied high catalytic activity. However, their inferior structural and compositional stability during catalysis pose as formidable huddles to their practical applications. Herein, it is reported that introduction of an additional component to the binary catalytic system may serve as a simple and effective means of enhancing the structural and compositional stability of nanoframe-based electrocatalysts. It is demonstrated that in situ doping of Co to the PtCu alloy nanoframe yields a ternary PtCuCo rhombic dodecahedral nanoframe (Co-PtCu RNF) with a reinforced vertex structure. Co-PtCu RNF exhibits superior electrocatalytic activity and durability for the oxygen reduction reaction to those of PtCu rhombic dodecahedral nanoframe (PtCu RNF) and Pt/C catalysts, due to its ternary composition and vertex-strengthened frame structure. Furthermore, Co-PtCu RNF shows enhanced activity for the methanol oxidation reaction as compared to PtCu RNF and Pt/C.Novel vertex-reinforced ternary alloy nanoframes with Pt, Cu, and Co exhibit excellent electrocatalytic activity and stability toward the oxygen reduction and the methanol oxidation under acidic condition compared to binary PtCu nanoframes.
      PubDate: 2018-01-18T05:18:44.127492-05:
      DOI: 10.1002/adfm.201706440
       
  • Oxygen-Generating MnO2 Nanodots-Anchored Versatile Nanoplatform for
           Combined Chemo-Photodynamic Therapy in Hypoxic Cancer
    • Authors: Wentao Zhang; Sihang Li, Xinnan Liu, Chengyuan Yang, Na Hu, Leina Dou, Bingxin Zhao, Qinying Zhang, Yourui Suo, Jianlong Wang
      Abstract: Local hypoxia in tumors results in undesirable impediments for the efficiencies of oxygen-dependent chemical and photodynamic therapy (PDT). Herein, a versatile oxygen-generating and pH-responsive nanoplatform is developed by loading MnO2 nanodots onto the nanosystem that encapsulates g-C3N4 and doxorubicin hydrochloride to overcome the hypoxia-caused resistance in cancer therapy. The loaded MnO2 nanodots can react with endogenous acidic H2O2 to elevate the dissolved oxygen concentration, leading to considerably enhanced cancer therapy efficacy. As such, the as-prepared nanoplatform with excellent dispersibility and satisfactory biocompatibility can sustainably increase the oxygen concentration and rapidly release the encapsulated drugs in acid H2O2 environment. In vitro cytotoxicity experiments show a higher therapy effect by the designed nanoplatform, when compared to therapy without MnO2 nanodots under hypoxia condition, or chemical and photodynamic therapy alone with the presence of MnO2 nanodots. In vivo experiments also demonstrate that 4T1 tumors can be very efficiently eliminated by the designed nanoplatform under light irradiation. These results highlight that the MnO2 nanodots-based nanoplatform is promising for elevating the oxygen level in tumor microenvironments to overcome hypoxia limitations for high-performance cancer therapy.A MnO2 nanodots loaded nanoplatform reacting with endogenous acidic H2O2 to increase the oxygen concentration is demonstrated, overcoming hypoxia in tumors and simultaneously enhancing the efficiency of chemical and photodynamic therapy. The produced biocompatible nanoplatform exhibits a highly effective therapeutic effect in vitro and can eliminate the tumor in vivo.
      PubDate: 2018-01-18T05:18:07.429073-05:
      DOI: 10.1002/adfm.201706375
       
  • Diversified Photo/Electronic Functions Based on a Simple Chalcone
           Skeleton: Effects of Substitution Pattern and Molecular Packing
    • Authors: Xiao Cheng; Zhaoyang Wang, Baolei Tang, Hongyu Zhang, Anjun Qin, Jing Zhi Sun, Ben Zhong Tang
      Abstract: Structurally simple chalcone derivatives 1–2 are prepared and their diversified emission behaviors are deeply investigated. Two polymorphs (1G: λem = 536 nm, Φf = 0.08, τ = 1.81 ns; 1O: λem = 573 nm, Φf = 0.19, τ = 10.82 ns) with distinctively different emission behaviors are constructed by finely controlling the crystallization conditions of compound 1. 1G exhibits typical amplified spontaneous emission while 1O shows an interesting blue shift under smashing process (1O-S: λem = 562 nm, Φf = 0.23, τ = 6.42 ns), which is ascribed to their different molecular packing structures and intermolecular interactions. Notably, simply introducing a fluorine substituent effectively endows the crystal with red emission (crystal 2: λem = 598 nm, Φf = 0.16, τ = 18.77 ns). Thus multicolor emissions including green, yellow, orange, and red emissions are obtained based on this simple chalcone skeleton.Polymorphs 1G (λem = 536 nm, Фf = 0.08, t = 1.81 ns) and 1O (λem = 573 nm, Фf = 0.19, τ = 10.82 ns) displaying distinctively different emission behaviors are obtained based on a structurally simple D-A (Donor-Acceptor) type molecule. Notably, simply introducing a fluorine substituent effectively endows the crystal with red emission (crystal 2: λem = 598 nm, Фf = 0.16, t = 18.77 ns).
      PubDate: 2018-01-18T05:17:37.697251-05:
      DOI: 10.1002/adfm.201706506
       
  • Controllable Urchin-Like NiCo2S4 Microsphere Synergized with Sulfur-Doped
           Graphene as Bifunctional Catalyst for Superior Rechargeable Zn–Air
           Battery
    • Authors: Wenwen Liu; Jing Zhang, Zhengyu Bai, Gaopeng Jiang, Matthew Li, Kun Feng, Lin Yang, Yuanli Ding, Tongwen Yu, Zhongwei Chen, Aiping Yu
      Abstract: Rechargeable zinc–air batteries (ZnABs) are attracting great interest due to their high theoretical specific energy, safety, and economic viability. However, their performance and large-scale practical applications are largely limited by poor durability and high overpotential on the air-cathode due to the slow kinetics of the oxygen reduction and evolution reactions (ORR/OER). Therefore, it is highly desired to exploit an ideal bifunctional catalyst to endow the obtained ZnABs with excellent ORR/OER catalytic performances. Herein, a new nonprecious-metal bifunctional catalyst of urchin-like NiCo2S4 microsphere synergized with sulfur-doped graphene nanosheets (S-GNS/NiCo2S4) is controllably designed and synthesized by simply tailoring the structure and electronic arrangement, which endow the as-prepared catalyst with excellent electroactivity and long-term durability toward ORR and OER. Importantly, ZnABs constructed by this outstanding catalyst exhibit high power density, small charge/discharge voltage gap, and excellent cycle stability, notably outperforming the more costly commercial Pt/C + Ir/C mixture catalyst. These excellent electrocatalytic performances together with the simplicity of the synthetic method, make the urchin-like NiCo2S4 microsphere/S-GNS hybrid nanostructure exhibit great promise as a superior air-cathode catalyst for high-performance rechargeable ZnABs.A new nonprecious-metal bifunctional catalyst of urchin-like NiCo2S4 microsphere synergized with sulfur-doped graphene nanosheets (S-GNS/NiCo2S4) is successfully designed and constructed, which endows the as-prepared catalyst with excellent electroactivity and long-term durability toward oxygen reduction and evolution reactions. Importantly, Zn–air batteries constructed with this outstanding catalyst exhibits high power density, small charge/discharge voltage gap, and excellent cycle stability.
      PubDate: 2018-01-18T05:12:44.979064-05:
      DOI: 10.1002/adfm.201706675
       
  • Hybrid Organic/PbS Quantum Dot Bilayer Photodetector with Low Dark Current
           and High Detectivity
    • Authors: Yuanzhi Wei; Zhenwei Ren, Andong Zhang, Peng Mao, Hui Li, Xinhua Zhong, Weiwei Li, Shiyong Yang, Jizheng Wang
      Abstract: Owing to their ease of fabrication, low cost, and high flexibility, organic materials have attracted great interests in photodetector (PD) applications. However, suffering from large dark current, small photocurrent, low on–off ratio, and low sensitivity, performances of bare organic-based PDs are not satisfactory. Integrating organic materials with other novel semiconductor materials offers an opportunity to overcome these drawbacks. Here, a lateral hybrid organic/lead sulfide (PbS) quantum dot bilayer PD is designed and fabricated, which significantly suppresses the dark current and enhances the photocurrent, leading to improved light detecting capability. Meanwhile, the bilayer PD can be made on a flexible polyimide substrate.A hybrid organic/PbS quantum dot bilayer photodetector is designed and fabricated. Compared with bare organic and bare PbS devices, the bilayer device exhibits significantly improved performance in responsivity, detectivity, signal-to-noise ratio, and linear dynamic range. The device also shows potential in future flexible optoelectronics.
      PubDate: 2018-01-17T11:44:00.269639-05:
      DOI: 10.1002/adfm.201706690
       
  • Comprehensive Understanding of the Spatial Configurations of CeO2 in NiO
           for the Electrocatalytic Oxygen Evolution Reaction: Embedded or
           Surface-Loaded
    • Authors: Wei Gao; Zhaoming Xia, Fangxian Cao, Johnny C. Ho, Zheng Jiang, Yongquan Qu
      Abstract: Introducing cerium (Ce) species into electrocatalysts has been recently developed as an effective approach to improve their oxygen evolution reaction (OER) performance. Importantly, the spatial distribution of Ce species in the hosts can determine the availability of Ce species either as additives or as co-catalysts, which would dictate their different contributions to the enhanced electrocatalytic performance. Herein, the comprehensive investigations on two different catalyst configurations, namely CeO2-embedded NiO (Ce-NiO-E) and CeO2-surface-loaded NiO (Ce-NiO-L), are performed to understand the effect of their specific spatial arrangements on OER characteristics. The Ce-NiO-E catalysts exhibit a smaller overpotential of 382 mV for 10 mA cm−2 and a lower Tafel slope of 118.7 mV dec−1, demonstrating the benefits of the embedded configuration for OER, as compared with those of Ce-NiO-L (426 mV and 131.6 mV dec−1) and pure NiO (467 mV and 140.7 mV dec−1), respectively. The improved OER property of Ce-NiO-E originates from embedding small-sized CeO2 clusters into the host for the larger specific surface area, richer surface defects, higher oxygen adsorption capacity, and better optimized electronic structures of the surface active sites, as compared with Ce-NiO-L. Above findings provide a valuable guideline for and insight in designing catalysts with different spatial configurations for enhanced catalytic properties.Spatial distribution of CeO2 species as additives in the NiO host can dictate different contributions to the enhanced electrocatalytic oxygen evolution performance. The comparative study on two different catalyst configurations showed the benefits of embedding small-sized CeO2 clusters into NiO to modify the surface properties and structures and improve the activity as compared with CeO2 surface-loaded NiO.
      PubDate: 2018-01-17T03:01:54.90306-05:0
      DOI: 10.1002/adfm.201706056
       
  • Spatially Resolved Electric-Field Manipulation of Magnetism for CoFeB
           Mesoscopic Discs on Ferroelectrics
    • Authors: You Ba; Yan Liu, Peisen Li, Liang Wu, John Unguris, Daniel T. Pierce, Danni Yang, Ce Feng, Yike Zhang, Hao Wu, Dalai Li, Yuansi Chang, Jinxing Zhang, Xiufeng Han, Jianwang Cai, Ce-Wen Nan, Yonggang Zhao
      Abstract: Electric-field control of magnetism in ferromagnetic/ferroelectric multiferroic heterostructures is a promising way to realize fast and nonvolatile random-access memory with high density and low-power consumption. An important issue that has not been solved is the magnetic responses to different types of ferroelectric-domain switching. Here, for the first time three types of magnetic responses are reported induced by different types of ferroelectric domain switching with in situ electric fields in the CoFeB mesoscopic discs grown on PMN-PT(001), including type I and type II attributed to 109°, 71°/180° ferroelectric domain switching, respectively, and type III attributed to a combined behavior of multiferroelectric domain switching. Rotation of the magnetic easy axis by 90° induced by 109° ferroelectric domain switching is also found. In addition, the unique variations of effective magnetic anisotropy field with electric field are explained by the different ferroelectric domain switching paths. The spatially resolved study of electric-field control of magnetism on the mesoscale not only enhances the understanding of the distinct magnetic responses to different ferroelectric domain switching and sheds light on the path of ferroelectric domain switching, but is also important for the realization of low-power consumption and high-speed magnetic random-access memory utilizing these materials.Three types of magnetic responses induced by different types of ferroelectric (FE) domain switching are revealed, particularly, the first observation of 90° rotation of the magnetic easy axis induced by 109° FE domain switching. The result is significant for understanding the distinct magnetic responses to different types of FE domain switching and shedding light on the path of FE domain switching.
      PubDate: 2018-01-17T03:01:11.977624-05:
      DOI: 10.1002/adfm.201706448
       
  • High Energy Storage Performance of Opposite Double-Heterojunction
           Ferroelectricity–Insulators
    • Authors: Tiandong Zhang; Weili Li, Yu Zhao, Yang Yu, Weidong Fei
      Abstract: In this study, the excellent energy storage performance is achieved by constructing opposite double-heterojunction ferroelectricity–insulator–ferroelectricity configuration. The PbZr0.52Ti0.48O3 films and Al2O3 films are chosen as the ferroelectricity and insulator, respectively. The microstructures, polarization behaviors, breakdown strength, leakage current density, and energy storage performance are investigated systematically of the constructed PbZr0.52Ti0.48O3/Al2O3/PbZr0.52Ti0.48O3 opposite double-heterojunction. The ultrahigh electric field breakdown strength (≈5711 kV cm−1) is obtained, which is beneficial to achieve high energy storage density. Meanwhile, the high linearity of hysteresis loops with low energy dissipation is obtained at a proper annealing temperature, which is induced by partially crystallized and is in favor of achieving high energy storage efficiency η. The PbZr0.52Ti0.48O3/Al2O3/PbZr0.52Ti0.48O3 annealed at 550 °C exhibits excellent energy storage performance with a storage density of 63.7 J cm−3 and efficiency of 81.3%, which is ascribed to the synergetic effect of electric breakdown strength (EBDS = 5711 kV cm−1) and the polarization (Pm–Pr = 23.74 µC cm−2). The proposed method in this study opens a new door to improve the energy storage performance of inorganic ferroelectric capacitors.The opposite double-heterojunction ferroelectricity–insulator–ferroelectricity configuration is proposed for the enhancement of electric breakdown strength and energy storage density of PbZr0.52Ti0.48O3/Al2O3/PbZr0.52Ti0.48O3 films. The high energy storage efficiency accompanying with high linearity of hysteresis loops is achieved by regulating the annealing temperature. Ultrahigh energy storage density of 63.7 J cm−3 with excellent efficiency of 81.3% is obtained in PbZr0.52Ti0.48O3/Al2O3/PbZr0.52Ti0.48O3 heterojunction films.
      PubDate: 2018-01-17T02:57:11.037885-05:
      DOI: 10.1002/adfm.201706211
       
  • Optomagnetic Nanoplatforms for In Situ Controlled Hyperthermia
    • Authors: Dirk H. Ortgies; Francisco J. Teran, Uéslen Rocha, Leonor de la Cueva, Gorka Salas, David Cabrera, Alexander S. Vanetsev, Mihkel Rähn, Väino Sammelselg, Yurii V. Orlovskii, Daniel Jaque
      Abstract: Magnetic nanoparticles (M:NPs) are unique agents for in vivo thermal therapies due to their multimodal capacity for efficient heat generation under optical and/or magnetic excitation. Nevertheless, their transfer from laboratory to the clinic is hampered by the absence of thermal feedback and by the influence that external conditions (e.g., agglomeration and biological matrix interactions) have on their heating efficiency. Overcoming these limitations requires, first, the implementation of strategies providing thermal sensing to M:NPs in order to obtain in situ thermal feedback during thermal therapies. At the same time, M:NPs should be modified so that their heating efficiency will be maintained independently of the environment and the added capability for thermometry. In this work, optomagnetic hybrid nanostructures (OMHSs) that simultaneously satisfy these two conditions are presented. Polymeric encapsulation of M:NPs with neodymium-doped nanoparticles results in a hybrid structure capable of subtissue thermal feedback while making the heating efficiency of M:NPs independent of the medium. The potential application of the OMHSs herein developed for fully controlled thermal therapies is demonstrated by an ex vivo endoscope-assisted controlled intracoronary heating experiment.The combination of magnetic nanoparticles and luminescent nanothermometers through encapsulation with a polymer into optomagnetic hybrid nanostructures achieves in situ control of thermal therapies inside biological tissues. The magnetic and luminescent properties of the constituting nanoparticles are maintained, and the robustness of the thermal feedback during photothermal and/or magnetic heating is demonstrated.
      PubDate: 2018-01-17T02:56:43.133412-05:
      DOI: 10.1002/adfm.201704434
       
  • Synthesis of Nanostructured PbO@C Composite Derived from Spent Lead-Acid
           Battery for Next-Generation Lead-Carbon Battery
    • Authors: Yuchen Hu; Jiakuan Yang, Jingping Hu, Junxiong Wang, Sha Liang, Huijie Hou, Xu Wu, Bingchuan Liu, Wenhao Yu, Xiong He, R. Vasant Kumar
      Abstract: Lead-carbon batteries could provide better performance on high-rate partial-state-of-charge (HRPSoC) cycles than lead-acid batteries (LABs), making them promising for the new-generation of hybrid electric vehicles. The addition of carbon allotropes to the negative active material (NAM) could induce a significant improvement to the battery performance. Herein, an environmentally friendly strategy is demonstrated to prepare lead oxide and carbon (PbO@C) composite by pyrolyzing the lead citrate precursor derived from the spent lead paste of LABs. When the PbO@C composite is used as an additive to the NAM of lead-carbon batteries, the utilization efficiency of the NAM is improved from 56.9% to 72.5%, and the cycle life of the cell in HRPSoC is tremendously extended by four times compared with the control one. The enhancement in battery performance is attributed to the hydrophilic carbon in the composite, which acts as a 3D electroosmotic pump facilitating electrolyte diffusion, and hindering the tendency to excess sulfation during the HRPSoC operation. This proposed research provides a sustainable and scalable strategy to recycle the discarded/spent LABs into high-performance lead-carbon batteries.An environmentally friendly strategy to prepare lead oxide and carbon (PbO@C) composites by pyrolyzing the lead citrate precursor recycled from discarded lead-acid batteries (LAB) is demonstrated. This study will shed light on the development of the advanced electrode materials for lead-carbon batteries and provide an alternative strategy to combine the recycling of discarded LAB with reutilization in next-generation lead-carbon batteries.
      PubDate: 2018-01-17T02:56:17.894238-05:
      DOI: 10.1002/adfm.201705294
       
  • Direct 3D Printing of High Strength Biohybrid Gradient Hydrogel Scaffolds
           for Efficient Repair of Osteochondral Defect
    • Authors: Fei Gao; Ziyang Xu, Qingfei Liang, Bo Liu, Haofei Li, Yuanhao Wu, Yinyu Zhang, Zifeng Lin, Mingming Wu, Changshun Ruan, Wenguang Liu
      Abstract: The emerging 3D printing technique allows for tailoring hydrogel-based soft structure tissue scaffolds for individualized therapy of osteochondral defects. However, the weak mechanical strength and uncontrollable swelling intrinsic to conventional hydrogels restrain their use as bioinks. Here, a high-strength thermoresponsive supramolecular copolymer hydrogel is synthesized by one-step copolymerization of dual hydrogen bonding monomers, N-acryloyl glycinamide, and N-[tris(hydroxymethyl)methyl] acrylamide. The obtained copolymer hydrogels demonstrate excellent mechanical properties—robust tensile strength (up to 0.41 MPa), large stretchability (up to 860%), and high compressive strength (up to 8.4 MPa). The rapid thermoreversible gel sol transition behavior makes this copolymer hydrogel suitable for direct 3D printing. Successful preparation of 3D-printed biohybrid gradient hydrogel scaffolds is demonstrated with controllable 3D architecture, owing to shear thinning property which allows continuous extrusion through a needle and also immediate gelation of fluid upon deposition on the cooled substrate. Furthermore, this biohybrid gradient hydrogel scaffold printed with transforming growth factor beta 1 and β-tricalciumphosphate on distinct layers facilitates the attachment, spreading, and chondrogenic and osteogenic differentiation of human bone marrow stem cells (hBMSCs) in vitro. The in vivo experiments reveal that the 3D-printed biohybrid gradient hydrogel scaffolds significantly accelerate simultaneous regeneration of cartilage and subchondral bone in a rat model.A high strength biohybrid hydrogel scaffold with precisely designed gradient/architecture, and controllable loading of transforming growth factor beta 1 and β-tricalciumphosphate particles in distinct layers, mimicking an osteochondral tissue and its micromilieu, is custom-made by a one-step thermal-assisted extrusion printing technique. The seamless integrated scaffold demonstrates an excellent ability to boost simultaneous osteochondral regeneration in a rat model.
      PubDate: 2018-01-17T02:52:25.128837-05:
      DOI: 10.1002/adfm.201706644
       
  • Molecular Consideration for Small Molecular Acceptors Based on Ladder-Type
           Dipyran: Influences of O-Functionalization and π-Bridges
    • Authors: Lisi Yang; Miao Li, Jinsheng Song, Yuanyuan Zhou, Zhishan Bo, Hua Wang
      Abstract: Molecular engineering of nonfullerene acceptors (NFAs) plays a vital role in the development of organic photovoltaics. Oxygen as an electron donating atom is incorporated into the NFA system as alkoxyl forms at central, terminal, or central conjugated moieties due to the tunability at structural conformation, solubility, electron donating ability, absorption, energy levels, etc. In this work, a novel dipyran-based ladder-type building block (Ph-DTDP), which possesses two oxygen atoms in the conjugated skeleton, is designed and facilely synthesized. It is applied as the donor core for the acceptor–donor–acceptor-type NFA design and such functionalized-O efficiently enhances the electron donating ability, lowers the band gap, redshifts and extends the absorption spectra. In addition, the π-bridge effects are considered as well. Photovoltaic performances are systematically investigated and a high power conversion efficiency of 9.21% can be afforded with an energy loss of 0.57 eV. Meanwhile, the morphologies as well as the carrier mobilities of the blend films are studied to assist further understanding of the structure–property relationships. Overall, the study in this work provides a new promising ladder-type dipyran building block and brings in a novel way to use oxygen in NFA molecular structure design.Dipyran-based ladder-type building block (Ph-DTDP), which possesses two oxygen atoms in the conjugated skeleton and four flanking hexylphenyl side chains, is facilely synthesized. The corresponding acceptor–donor–acceptor-type nonfullerene acceptors are prepared and the influences of O-functionalization and π-bridges on energy levels, absorption spectra, crystalinity, morphologies, and photovoltaic performances are systematically studied.
      PubDate: 2018-01-17T02:51:38.870173-05:
      DOI: 10.1002/adfm.201705927
       
  • Achieving of Flexible, Free-Standing, Ultracompact Delaminated Titanium
           Carbide Films for High Volumetric Performance and Heat-Resistant Symmetric
           Supercapacitors
    • Authors: Chenhui Yang; Yi Tang, Yapeng Tian, Yangyang Luo, Yucheng He, Xingtian Yin, Wenxiu Que
      Abstract: The volumetric performance of supercapacitors (SCs), besides the gravimetric performance, is attracting an increasing attention due to the fast development of electric vehicles and smart devices. Here, a unique design of symmetric supercapacitor material is reported with a tight face-to-face architecture by applying a high pressure to the delaminated Ti3C2 (d-Ti3C2) films. The high pressure makes the d-Ti3C2 films achieve an increased density, high electron conductivity, good wettability, and abundant interconnected mesopore channels to promote ion transport efficiently, that is, more cations can intercalate/deintercalate in the charging–discharging process. As a result, with the increase of the applying pressure, the d-Ti3C2 film pressured at 40 MPa in 1 m Li2SO4 exhibits an ultrahigh capacitance of over 633 F cm−3, outstanding energy density, and cyclic stability. Especially, the corresponding SC in 1 m 1-ethyl-3-methylimidazolium tetrafluoroborate/acetonitrile organic electrolyte shows a high volumetric energy density of 41 Wh L−1, which is the highest value reported for the SCs based on MXene materials in organic electrolytes. The outstanding volumetric electrochemical performance and thermal stability of the SCs based on the ultracompact d-Ti3C2 film demonstrate their promising potential as forceful power sources for small electronic devices.Flexible, free-standing, ultracompact delaminated titanium carbide films based symmetric supercapacitors are developed through applying a high pressure to the delaminated Ti3C2 films to achieve a tight face-to-face architecture. The outstanding volumetric electrochemical and heat-resistant performances of the supercapacitors based on the ultracompact delaminated Ti3C2 films demonstrate their promising potential as forceful power sources for small electronic devices.
      PubDate: 2018-01-17T02:51:15.645026-05:
      DOI: 10.1002/adfm.201705487
       
  • Self-Doping Fullerene Electrolyte-Based Electron Transport Layer for
           All-Room-Temperature-Processed High-Performance Flexible Polymer Solar
           Cells
    • Authors: Jingwen Zhang; Rongming Xue, Guiying Xu, Weijie Chen, Guo-Qing Bian, Changan Wei, Yaowen Li, Yongfang Li
      Abstract: To achieve high-performance large-area flexible polymer solar cells (PSCs), one of the challenges is to develop new interface materials that possess a thermal-annealing-free process and thickness-insensitive photovoltaic properties. Here, an n-type self-doping fullerene electrolyte, named PCBB-3N-3I, is developed as electron transporting layer (ETL) for the application in PSCs. PCBB-3N-3I ETL can be processed at room temperature, and shows excellent orthogonal solvent processability, substantially improved conductivity, and appropriate energy levels. PCBB-3N-3I ETL also functions as light-harvesting acceptor in a bilayer solar cell, contributing to the overall device performance. As a result, the PCBB-3N-3I ETL-based inverted PSCs with a PTB7-Th:PC71BM photoactive layer demonstrate an enhanced power conversion efficiency (PCE) of 10.62% for rigid and 10.04% for flexible devices. Moreover, the device avoids a thermal annealing process and the photovoltaic properties are insensitive to the thickness of PCBB-3N-3I ETL, yielding a PCE of 9.32% for the device with thick PCBB-3N-3I ETL (61 nm). To the best of one's knowledge, the above performance yields the highest efficiencies for the flexible PSCs and thick ETL-based PSCs reported so far. Importantly, the flexible PSCs with PCBB-3N-3I ETL also show robust bending durability that could pave the way for the future development of high-performance flexible solar cells.An n-type doping fullerene electrolyte (PCBB-3N-3I) with high-content doping groups, resulting in high conductivity and well-matched energy levels, is synthesized. The inverted polymer solar cells with PCBB-3N-3I electron transport layer show a record efficiency in the flexible polymer solar cells with an extremely high bending durability and thickness-insensitive photovoltaic behavior.
      PubDate: 2018-01-17T02:46:05.856794-05:
      DOI: 10.1002/adfm.201705847
       
  • 2D WC/WO3 Heterogeneous Hybrid for Photocatalytic Decomposition of Organic
           Compounds with Vis–NIR Light
    • Authors: Song Ling Wang; Ye Zhu, Xin Luo, Yun Huang, Jianwei Chai, Ten It Wong, Guo Qin Xu
      Abstract: Developing catalysts to improve charge-carrier transfer and separation is critical for efficient photocatalytic applications driven by low-energy photons. van der Waals stacking of 2D materials has opened up opportunities to engineer heteromaterials for strong interlayer excitonic transition. However, fabrication of 2D heteromaterials with clean and seamless interfaces remains challenging. Here, a 2D tungsten carbide/tungsten trioxide (WC/WO3) heterogeneous hybrid in situ synthesized by a chemical engineering method has been reported. The hybrid comprises of layer-by-layer stacked WC and WO3 monolayers. The WC and specific interfacial interfaces between the WC and WO3 layers exhibit synergetic effects, promoting interfacial charge transfer and separation. Binderless WC performing platinum-like behavior works as a potential substitute for noble metals and accelerates multielectron oxygen reduction, consequently speeding up the photocatalytic decomposition of organic compounds over the WO3 catalyst. The specific interfacial interaction between WC and WO3 layers potentially improves interfacial charge transfer from conduction band of WO3 to WC. In the absence of noble metals, the WC/WO3 hybrid as a catalyst exhibits distinct decomposition of organic compounds with vis–NIR light (λ = 400–800 nm). This finding provides a cost-effective approach to capture low-energy photons in environmental remediation applications.2D WC/WO3 heterogeneous hybrid is synthesized via an in situ chemical engineering method. The hybrid comprising of layer-by-layer stacked WC and WO3 exhibits distinct charge transfer and separation. In the absence of noble metals, the WC/WO3 hybrid exhibits excellent oxidative decomposition of organic compounds driven by the low-energy photons (vis–NIR light).
      PubDate: 2018-01-17T02:43:23.33945-05:0
      DOI: 10.1002/adfm.201705357
       
  • A Novel Hydrogel Surface Grafted With Dual Functional Peptides for
           Sustaining Long-Term Self-Renewal of Human Induced Pluripotent Stem Cells
           and Manipulating Their Osteoblastic Maturation
    • Authors: Yi Deng; Shicheng Wei, Lei Yang, Weizhong Yang, Matthew S. Dargusch, Zhi-Gang Chen
      Abstract: Realizing the clinical potential of human induced pluripotent stem cells (hiPSCs) in bone regenerative medicine requires the development of safe and chemically defined biomaterials for expansion of hiPSCs followed by directing their lineage commitment to osteoblasts. In this study, novel multipurpose peptide-presenting hydrogel surfaces are prepared on common tissue culture plates via carboxymethyl chitosan grafting and subsequent immobilization of two functional peptides allowing for in vitro feeder-free culture, long-term self-renewal, and osteogenic induction of hiPSCs. After vitronectin (VN) peptide modification, the engineered surfaces facilitate adhesion, proliferation, colony formation, and the maintenance of pluripotency of hiPSCs up to passage 10 under fully defined conditions without Matrigel or protein coating. Further, this synthetic niche exhibits an appealing regulatory effect on the osteogenic conversion of hiPSCs to osteoblastic phenotype without an embryoid body formation step by co-decoration of different ratios of VN and bone-forming peptide. Such a well-defined, xeno-free 2D engineered microenvironment not only helps to accelerate the clinical development of hiPSCs, but also provides a safe and robust platform for the generation of osteoblast-like cells or bone-like tissues at different maturation levels. Thus, the strategy may hold great potential for application in cell therapy and bone tissue engineering.A well-defined, xeno-free, and multipurpose peptide-presenting hydrogel surface is developed on the tissue culture plate via carboxymethyl chitosan grafting and subsequent immobilization of two functional peptides. Such an unique surface can support the culture and manipulation of the osteoblastic maturation of human induced pluripotent stem cells, showing a great promise for the bone regenerative medicine and tissue engineering.
      PubDate: 2018-01-17T02:42:03.592754-05:
      DOI: 10.1002/adfm.201705546
       
  • Efficient Nondoped Blue Fluorescent Organic Light-Emitting Diodes (OLEDs)
           with a High External Quantum Efficiency of 9.4% @ 1000 cd m−2 Based on
           Phenanthroimidazole−Anthracene Derivative
    • Authors: Xiangyang Tang; Qing Bai, Tong Shan, Jinyu Li, Yu Gao, Futong Liu, Hui Liu, Qiming Peng, Bing Yang, Feng Li, Ping Lu
      Abstract: Organic light-emitting diodes (OLEDs) can promise flexible, light weight, energy conservation, and many other advantages for next-generation display and lighting applications. However, achieving efficient blue electroluminescence still remains a challenge. Though both phosphorescent and thermally activated delayed fluorescence materials can realize high-efficiency via effective triplet utilization, they need to be doped into appropriate host materials and often suffer from certain degree of efficiency roll-off. Therefore, developing efficient blue-emitting materials suitable for nondoped device with little efficiency roll-off is of great significance in terms of practical applications. Herein, a phenanthroimidazole−anthracene blue-emitting material is reported that can attain high efficiency at high luminescence in nondoped OLEDs. The maximum external quantum efficiency (EQE) of nondoped device is 9.44% which is acquired at the luminescence of 1000 cd m−2. The EQE is still as high as 8.09% even the luminescence reaches 10 000 cd m−2. The maximum luminescence is ≈57 000 cd m−2. The electroluminescence (EL) spectrum shows an emission peak of 470 nm and the Commission International de L'Eclairage (CIE) coordinates is (0.14, 0.19) at the voltage of 7 V. To the best of the knowledge, this is among the best results of nondoped blue EL devices.An efficient blue fluorescent material PIAnCN is reported that exhibits a maximum external quantum efficiency (EQE) of 9.44% in nondoped organic light-emitting diodes (OLEDs). The device shows little efficiency roll-off. The EQE is 9.44% at 1000 cd m−2 and still remains as high as 8.09% at 10 000 cd m−2. To best knowledge, this is among the best results of nondoped blue fluorescent OLEDs.
      PubDate: 2018-01-17T02:40:49.603145-05:
      DOI: 10.1002/adfm.201705813
       
  • Energy Landscape of Vertically Anisotropic Polymer Blend Films toward
           Highly Efficient Polymer Light-Emitting Diodes (PLEDs)
    • Authors: Muhammad Umair Hassan; Yee-Chen Liu, Ali K. Yetisen, Haider Butt, Richard Henry Friend
      Abstract: A blend of two hole-dominant polymers is created and used as the light emissive layer in light-emitting diodes to achieve high luminous efficiency up to 22 cd A−1. The polymer blend F81−xSYx is based on poly(9,9-dioctylfluorene) (F8) and poly(para-phenylene vinylene) derivative superyellow (SY). The blend system exhibits a preferential vertical concentration distribution. The resulting energy landscape modifies the overall charge transport behavior of the blend emissive layer. The large difference between the highest unoccupied molecular orbital levels of F8 (5.8 eV) and SY (5.3 eV) introduces hole traps at SY sites within the F8 polymer matrix. This slows down the hole mobility and facilitates a balance between the transport behavior of both the charge carriers. The balance due to such energy landscape facilitates efficient formation of excitons within the emission zone well away from the cathode and minimizes the surface quenching effects. By bringing the light-emission zone in the middle of the F81−xSYx film, the bulk of the film is exploited for the light emission. Due to the charge trapping nature of SY molecules in F8 matrix and pushing the emission zone in the center, the radiative recombination rate also increases, resulting in excellent device performance.Light-emitting polymer films based on the blend of poly(9,9-dioctylfluorene) and poly(para-phenylene vinylene) derivative superyellow exhibit a preferential vertical concentration distribution. A nonuniform energy landscape due to the large difference between the highest occupied molecular levels of both polymers balances the charge transport in the films and leads to achieving highly efficient light-emitting diodes.
      PubDate: 2018-01-17T02:36:05.36504-05:0
      DOI: 10.1002/adfm.201705903
       
  • Rational Molecular Design for Deep-Blue Thermally Activated Delayed
           Fluorescence Emitters
    • Authors: Chin-Yiu Chan; Lin-Song Cui, Jong Uk Kim, Hajime Nakanotani, Chihaya Adachi
      Abstract: By simple modification of the functional groups on the donor unit, the thermally activated delayed fluorescence (TADF) properties of emitters can easily be manipulated. A series of deep blue to blue emissive TADF derivatives is developed, capable of deep-blue emissions from 403 to 460 nm in toluene. Deep-blue organic light-emitting diodes (OLEDs) based on this series of TADF emitters are fabricated, resulting in an electroluminescence peak at 428 nm and a high external quantum efficiency of up to 10.3%. One deep-blue OLED has achieved the commission internationale de l'eclairage (CIE) coordinates of (0.156, 0.063), which is among the best reported TADF performances for deep-blue OLEDs with CIEy < 0.07.A series of deep-blue to blue emissive TADF derivatives is developed, by which deep-blue emissions from 403 to 460 nm in toluene are achieved. Deep-blue OLEDs based on this series of TADF emitters are fabricated, exhibiting an electroluminescence peak at 428 nm and a high external quantum efficiency of up to 10.3%.
      PubDate: 2018-01-17T02:35:40.727083-05:
      DOI: 10.1002/adfm.201706023
       
  • Multiwalled Carbon Nanotubes Induced Hypotension by Regulating the Central
           Nervous System
    • Authors: Xiaowei Ma; Lin Zhong, Hongbo Guo, Yifeng Wang, Ningqiang Gong, Yuqing Wang, Jun Cai, Xing-Jie Liang
      Abstract: Cardiovascular disease is the leading cause of death worldwide. Normal blood pressure is very important for overall well-being and unexpected decrease in blood pressure may cause many detrimental consequences. The attractive properties of multiwalled carbon nanotubes (MWCNTs) entice their usage in many cutting edge brain-specific therapies. However, the effects of MWCNTs to the central nervous system are not fully understood. In this work, the authors report that carbon nanotubes can significantly cause blood pressure to fall down when introduced into the brain at very low dosage. It is found that MWCNTs induce increased expression of neuronal nitric oxide synthase in the medulla cardiovascular center, which consequently attenuate sympathetic nerve activity and cause decrease in blood pressure and heart rate. In addition, MWCNTs promote acetylation and nuclear translocation of nuclear factor-κB in brain cells. This work illustrates how CNTs can potentially change blood pressure by interrupting the central nervous system and is significant to the biomedical applications of CNTs.The blood pressure is governed by the central nervous system and normal blood pressure is vital for overall well-being. Multiwalled carbon nanotubes induce increased expression of neuronal nitric oxide synthase in nucleus tractus solitaries and rostral ventrolateral medulla, which consequently attenuate sympathetic nerve activity and cause decrease in blood pressure and heart rate.
      PubDate: 2018-01-17T02:30:51.683219-05:
      DOI: 10.1002/adfm.201705479
       
  • Octadecylamine-Functionalized Single-Walled Carbon Nanotubes for
           Facilitating the Formation of a Monolithic Perovskite Layer and Stable
           Solar Cells
    • Authors: Vincent Tiing Tiong; Ngoc Duy Pham, Teng Wang, Tianxiang Zhu, Xinluo Zhao, Yaohong Zhang, Qing Shen, John Bell, Linhua Hu, Songyuan Dai, Hongxia Wang
      Abstract: Organic–inorganic lead halide perovskites have shown great future for application in solar cells owing to their exceptional optical and electronic properties. To achieve high-performance perovskite solar cells, a perovskite light absorbing layer with large grains is desirable in order to minimize grain boundaries and recombination during the operation of the device. Herein, a simple yet efficient approach is developed to synthesize perovskite films consisting of monolithic-like grains with micrometer size through in situ deposition of octadecylamine functionalized single-walled carbon nanotubes (ODA-SWCNTs) onto the surface of the perovskite layer. The ODA-SWCNTs form a capping layer that controls the evaporation rate of organic solvents in the perovskite film during the postthermal treatment. This favorable morphology in turn dramatically enhances the short-circuit current density of the perovskite solar cells and almost completely eliminates the hysteresis. A maximum power conversion efficiency of 16.1% is achieved with an ODA-SWCNT incorporated planar solar cell using (FA0.83MA0.17)0.95Cs0.05Pb(I0.83Br0.17)3 as light absorber. Furthermore, the perovskite solar cells with ODA-SWCNT demonstrate extraordinary stability with performance retention of 80% after 45 d stability testing under high humidity (60–90%) environment. This work opens up a new avenue for morphology manipulation of perovskite films and enhances the device stability using carbon material.In situ deposition of a capping layer of octadecylamine functionalized single-walled carbon nanotubes onto the surface of perovskite films generates beneficial effects including improved perovskite grain size, reduced ion migration, and water repellency. Consequently, improved efficiency, stability, and reduced hysteresis of perovskite solar cells (PSCs) are achieved. This work demonstrates the potential of carbon nanotubes in enhancing the performance of PSCs.
      PubDate: 2018-01-17T02:27:40.557747-05:
      DOI: 10.1002/adfm.201705545
       
  • Stabilization of Glucagon by Trehalose Glycopolymer Nanogels
    • Authors: Natalie Boehnke; Jacquelin K. Kammeyer, Robert Damoiseaux, Heather D. Maynard
      Abstract: Glucagon is a peptide hormone used for the treatment of hypoglycemia; however, its clinical potential is limited by its insolubility and instability in solution. Herein, the encapsulation, stabilization, and release of glucagon by trehalose glycopolymer nanogels are reported. Methacrylate-functionalized trehalose is copolymerized with pyridyl disulfide ethyl methacrylate using free radical polymerization conditions to form trehalose glycopolymers with thiol-reactive handles. Glucagon is chemically modified to contain two thiol groups and is subsequently utilized as the cross-linker to form redox-responsive trehalose nanogels with greater than 80% conjugation yield. Nanogel formation and subsequent glucagon stabilization are characterized using polyacrylamide gel electrophoresis, dynamic light scattering, and transmission electron microscopy. It is determined that the solution stability of the glucagon increased from less than 24 h to at least three weeks in the nanogel form. Additionally, in vitro activity of the synthesized glucagon analog and released glucagon is investigated, demonstrating that the glucagon remains active after modification. It is anticipated that these glucagon–nanogel conjugates will be useful as a stabilizing glucagon formulation, allowing for cargo release under mild reducing conditions.Trehalose glycopolymer nanogels encapsulate and stabilize glucagon, an unstable therapeutic peptide hormone, for significantly improved solubility and long-term stability in solution. Glucagon is incorporated into the nanogels via redox-responsive cross-links, allowing for high peptide loading and release under mild reducing conditions. The released glucagon is bioactive by cellular assays, suggesting this system may be useful as a stabilizing glucagon formulation.
      PubDate: 2018-01-17T02:26:47.078868-05:
      DOI: 10.1002/adfm.201705475
       
  • Rational Design of Perylenediimide-Substituted Triphenylethylene to
           Electron Transporting Aggregation-Induced Emission Luminogens (AIEgens)
           with High Mobility and Near-Infrared Emission
    • Authors: Zheng Zhao; Simin Gao, Xiaoyan Zheng, Pengfei Zhang, Wenting Wu, Ryan T. K. Kwok, Yu Xiong, Nelson L. C. Leung, Yuncong Chen, Xike Gao, Jacky W. Y. Lam, Ben Zhong Tang
      Abstract: Organic materials with both high electron mobility and strong solid-state emission are rare although for their importance to advanced organic optoelectronics. In this paper, triphenylethylenes with varying number of perylenediimide (PDI) unit (TriPE-nPDIs, n = 1−3) are synthesized and their optical and charge-transporting properties are systematically investigated. All the molecules exhibit strong solid-stated near infrared (NIR) emission and some of them exhibit aggregation-enhanced emission characteristics. Organic field-effect transistors (OFETs) using TriPE-nPDIs are fabricated. TriPE-3PDI shows the best performance with maximum quantum yield of ≈30% and optimized electron mobility of over 0.01 cm2 V−1 s−1, which are the highest values among aggregation-induced emission luminogens with NIR emissions reported so far. Photophysical property investigation and theoretical calculation indicate that the molecular conformation plays an important role on the optical properties of TriPE-nPDI, while the result from film microstructure study reveals that the film crystallinity influences greatly their OFET device performance.N-type semiconductors with high electron mobility, strong near-infrared emission are constructed from aggregation-induced emission luminogen (AIEgen) and perylenediimide (PDI). The effect of PDI substitution on their optical and charge-transporting properties is investigated. The current work provides important clues for constructing high mobility semiconducting emitters and demonstrates the great potential of AIEgens in organic photoelectronics.
      PubDate: 2018-01-17T02:25:40.707486-05:
      DOI: 10.1002/adfm.201705609
       
  • Identification and Regulation of Active Sites on Nanodiamonds:
           Establishing a Highly Efficient Catalytic System for Oxidation of Organic
           Contaminants
    • Authors: Penghui Shao; Jiayu Tian, Feng Yang, Xiaoguang Duan, Shanshan Gao, Wenxin Shi, Xubiao Luo, Fuyi Cui, Shenglian Luo, Shaobin Wang
      Abstract: Nanodiamonds exhibit great potential as green catalysts for remediation of organic contaminants. However, the specific active site and corresponding oxidative mechanism are unclear, which retard further developments of high-performance catalysts. Here, an annealing strategy is developed to accurately regulate the content of ketonic carbonyl groups on nanodiamonds; meanwhile other structural characteristics of nanodiamonds remain almost unchanged. The well-defined nanodiamonds with well-controlled ketonic carbonyl groups exhibit excellent catalytic activity in activation of peroxymonosulfate for oxidation of organic pollutants. Based on the semi-quantitative and quantitative correlations of ketonic carbonyl groups and the reaction rate constants, it is conclusively determined that ketonic carbonyl groups are the catalytically active sites. Different from conventional oxidative systems, reactive oxygen species in nanodiamonds@peroxymonosulfate system are revealed to be singlet oxygen with high selectivity, which can effectively oxidize and mineralize the target contaminants. Impressively, the singlet-oxygen-mediated oxidation system significantly outperforms the classical radicals-based oxidation system in remediation of actual wastewater. This work not only provides a valuable insight for the design of new nanocarbon catalysts with abundant active sites but also establishes a very promising catalytic oxidation system for the green remediation of actual contaminated water.Ketonic carbonyl groups on nanodiamonds are conclusively determined as active sites, which can catalyze peroxymonosulfate dissolution into singlet oxygen with high selectivity. The singlet-oxygen-mediated oxidation system significantly outperforms the classical radical-based oxidation system in the remediation of organic contaminants in the actual water body.
      PubDate: 2018-01-17T02:20:44.626006-05:
      DOI: 10.1002/adfm.201705295
       
  • A Highly Stretchable Cross-Linked Polyacrylamide Hydrogel as an Effective
           Binder for Silicon and Sulfur Electrodes toward Durable Lithium-Ion
           Storage
    • Authors: Xingyu Zhu; Fei Zhang, Li Zhang, Liya Zhang, Yingze Song, Tao Jiang, Shah Sayed, Chen Lu, Xiangguo Wang, Jingyu Sun, Zhongfan Liu
      Abstract: Despite the recent advancement in the in-practical active materials (e.g., silicon, sulfur) in the rechargeable lithium-ion energy storage systems, daunting challenges still remain for these high-capacity electrode material candidates to overcome the severe volume changes associated with the repeated lithiation/delithiation process. Herein, developing a room-temperature covalently cross-linked polyacrylamide (c-PAM) binder with high stretchability and abundant polar groups targeting the construction of high-performance Si and sulfur electrodes is focused on. The robust 3D c-PAM binder network enables not only significant enhancement of the strain resistance for working electrodes but also strong affinity to bonding with nano-Si surface as well as effective capture of the soluble Li2Sn intermediates, thereby giving rise to remarkably improved cycling performances in both types of electrodes. This rational design of such an effective and multifunctional binder offers a pathway toward advanced energy storage implementations.A covalently cross-linked polyacrylamide hydrogel with high stretchability and abundant polar groups is utilized as binder material for fabricating high-strength silicon and sulfur electrodes. Such a multifunctional binder can provide strong affinity to bonding with the nanosilicon surface and trap the soluble polysulfide intermediates, resulting in remarkably improved electrochemical performance of both the silicon anodes and sulfur cathodes.
      PubDate: 2018-01-17T02:16:33.478833-05:
      DOI: 10.1002/adfm.201705015
       
  • Conformation Locking on Fused-Ring Electron Acceptor for High-Performance
           Nonfullerene Organic Solar Cells
    • Authors: Zhuohan Zhang; Jiangsheng Yu, Xinxing Yin, Zhenghao Hu, Yufeng Jiang, Jia Sun, Jie Zhou, Fujun Zhang, Thomas P. Russell, Feng Liu, Weihua Tang
      Abstract: In this work, sidechain engineering on conjugated fused-ring acceptors for conformation locking is demonstrated as an effective molecular design strategy for high-performance nonfullerene organic solar cells (OSCs). A novel nonfullerene acceptor (ITC6-IC) is designed and developed by introducing long alkyl chains into the terminal electron-donating building blocks. ITC6-IC has achieved definite conformation with a planar structure and better solubility in common organic solvents. The weak electron-donating hexyl upshifts the lowest unoccupied molecular orbital level of ITC6-IC, resulting in a higher VOC in comparison to the widely used ITIC. The OSCs based on PBDB-T:ITC6-IC reveal a promising power conversion efficiency of 11.61% and an expected high VOC of 0.97 V. The weaker π–π stacking induced by steric hindrance affords ITC6-IC with enhanced compatibility with polymer donors. The blend film treated with suitable thermal annealing exhibits a fibril crystallization feature with a good bicontinuous network morphology. The results indicate that the molecular design approach of ITC6-IC can be inspirational for future development of nonfullerene acceptors for high efficiency OSCs.Conformation locking by introducing alkyl chains onto central electron-donating building blocks has been explored on fused-ring electron acceptor for high-performance nonfullerene organic solar cells. PBDB-T:ITC6-IC based devices treated with suitable thermal annealing reveal a promising power conversion efficiency of 11.61% and an expected high VOC of 0.97 V with a small energy loss.
      PubDate: 2018-01-17T02:15:49.696428-05:
      DOI: 10.1002/adfm.201705095
       
  • Humidity-Induced Degradation via Grain Boundaries of HC(NH2)2PbI3 Planar
           Perovskite Solar Cells
    • Authors: Jae Sung Yun; Jincheol Kim, Trevor Young, Robert J. Patterson, Dohyung Kim, Jan Seidel, Sean Lim, Martin A. Green, Shujuan Huang, Anita Ho-Baillie
      Abstract: The sensitivity of organic–inorganic perovskites to environmental factors remains a major barrier for these materials to become commercially viable for photovoltaic applications. In this work, the degradation of formamidinium lead iodide (FAPbI3) perovskite in a moist environment is systematically investigated. It is shown that the level of relative humidity (RH) is important for the onset of degradation processes. Below 30% RH, the black phase of the FAPbI3 perovskite shows excellent phase stability over 90 d. Once the RH reaches 50%, degradation of the FAPbI3 perovskite occurs rapidly. Results from a Kelvin probe force microscopy study reveal that the formation of nonperovskite phases initiates at the grain boundaries and the phase transition proceeds toward the grain interiors. Also, ion migration along the grain boundaries is greatly enhanced upon degradation. A post-thermal treatment (PTT) that removes chemical residues at the grain boundaries which effectively slows the degradation process is developed. Finally, it is demonstrated that the PTT process improves the performance and stability of the final device.Moisture-induced degradation of FAPbI3 perovskite is systematically investigated. A Kelvin probe force microscopy study reveals that the formation of nonperovskite phases initiates at the grain boundaries and the phase transition proceeds toward the grain interiors. A post-thermal treatment that removes chemical residues at the grain boundaries which effectively slows the degradation process is developed.
      PubDate: 2018-01-17T02:10:52.720906-05:
      DOI: 10.1002/adfm.201705363
       
  • Thermally Activated Delayed Fluorescence Conjugated Polymers with
           Backbone-Donor/Pendant-Acceptor Architecture for Nondoped OLEDs with High
           External Quantum Efficiency and Low Roll-Off
    • Authors: Yike Yang; Shumeng Wang, Yunhui Zhu, Yanjie Wang, Hongmei Zhan, Yanxiang Cheng
      Abstract: Most thermally activated delayed fluorescence (TADF) emitters have to be doped in the host for fabricating efficient organic light-emitting diodes (OLEDs) and always suffer from quick efficiency roll-off at high brightness, which severely affect their commercial application in display and lighting fields. In the work, a series of the polymers are synthesized by copolymerization of two carbazole monomers and one acridine derivative monomer containing benzophenone acceptor group. The obtained polymers therefore possess a conjugated backbone with carbazole/acridine moieties and benzophenone pendant to form the twisted donor/acceptor structure. Consequently, the TADF features inherited from the acridine derivative are maintained and improved by managing the content of acridine derivative monomer in the polymers. Solution-processed OLEDs obtained from using neat polymer films exhibit comparable performance with organic TADF small molecules, achieving a maximum external quantum efficiency (EQE) of 18.1% and a very slow roll-off with EQE of 17.8% at the luminance of 1000 cd m−2.Conjugated polymers with a twisted donor backbone and an acceptor pendant structure possess prominent thermally activated delayed fluorescence. Nondoped devices based on these polymers exhibit excellent electroluminescence with a maximum external quantum efficiency (EQE) of 18.1% and a very slow roll-off with EQE of 17.8% at a luminance of 1000 cd m−2.
      PubDate: 2018-01-16T09:27:44.848865-05:
      DOI: 10.1002/adfm.201706916
       
  • A Type of 1 nm Molybdenum Carbide Confined within Carbon Nanomesh as
           Highly Efficient Bifunctional Electrocatalyst
    • Authors: Zhihua Cheng; Qiang Fu, Qing Han, Yukun Xiao, Yuan Liang, Yang Zhao, Liangti Qu
      Abstract: Highly efficient platinum-alternative bifunctional catalysts by using abundant non-noble metal species are of critical importance to the future sustainable energy reserves. Unfortunately, current electrocatalysts toward hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) are far from satisfactory because of lacking reasonable design and assembly protocols. A type of 1-nm molybdenum carbide nanoparticles confined in mesh-like nitrogen-doped carbon (Mo2C@NC nanomesh) with high specific surface area is reported here. In addition to the superior ORR performance comparable to platinum, the catalyst offers a high HER activity with small Tafel slope of 33.7 mV dec−1 and low overpotential of 36 mV to reach −10 mA cm−2. Theoretical calculations indicate that the active sites of the catalyst are mainly located at Mo atoms adjacent to the N-doped carbon layer, which contributes the high HER activity. These findings show the great potential of Mo2C species in wide electrocatalysis applications.1 nm molybdenum carbide nanoparticles embedded within a mesh-like nitrogen–carbon bifunctional catalyst are demonstrated. Such an unique architecture of molybdenum-based material exhibits superb hydrogen evolution and oxygen reduction performances, exceeding those of well-developed bifunctional non-noble metal based catalysts. This work exemplifies the possibility for achieving a Pt-alternative electrocatalyst from both the experimental and theoretical studies.
      PubDate: 2018-01-16T09:27:14.945242-05:
      DOI: 10.1002/adfm.201705967
       
  • Mechanically Robust, Self-Healable, and Highly Stretchable “Living”
           Crosslinked Polyurethane Based on a Reversible CC Bond
    • Authors: Ze Ping Zhang; Min Zhi Rong, Ming Qiu Zhang
      Abstract: Stimuli-responsive polymers built by reversible covalent bonds used to possess unbalanced mechanical properties. Here, a crosslinked polyurethane containing aromatic pinacol as a novel reversible CC bond provider is synthesized, whose tensile strength and failure strain are tunable from 27.3 MPa to as high as 115.2 MPa and from 324% to 1501%, respectively, owing to the relatively high bond energy of the CC bond of pinacol as well as the hydrogen bond between hard segments and semicrystalline soft segments. Moreover, the dynamic equilibrium of pinacol enables self-healing and recycling of the polymer. Interestingly, the dynamic exchange among macromolecules, for the first time, successfully cooperates with solid-state drawing that applies to thermoplastics, realizing strengthening of thermoset. Meanwhile, the radicals derived from homolysis of pinacol can repeatedly initiate polymerization of vinyl monomers. The fruitful outcomes of this work may create a series of promising new techniques.The CC bond of pinacol is dynamically reversible at moderate temperature. A crosslinked polyurethane carrying pinacol unit is synthesized, which can be self-healed, reprocessed, and recycled via the catalyst-free reversible homolysis/radicals recombination of the CC bond. Moreover, its strength can be greatly improved by solid-state drawing. The radicals created during homolysis are enabled to repeatedly initiate polymerization of vinyl monomers.
      PubDate: 2018-01-16T09:20:59.169469-05:
      DOI: 10.1002/adfm.201706050
       
  • Polydimethylsiloxane Composites for Optical Ultrasound Generation and
           Multimodality Imaging
    • Authors: Sacha Noimark; Richard J. Colchester, Radhika K. Poduval, Efthymios Maneas, Erwin J. Alles, Tianrui Zhao, Edward Z. Zhang, Michael Ashworth, Elena Tsolaki, Adrian H. Chester, Najma Latif, Sergio Bertazzo, Anna L. David, Sebastien Ourselin, Paul C. Beard, Ivan P. Parkin, Ioannis Papakonstantinou, Adrien E. Desjardins
      Abstract: Polydimethylsiloxane (PDMS) is widely used in biomedical science and can form composites that have broad applicability. One promising application where PDMS composites offer several advantages is optical ultrasound generation via the photoacoustic effect. Here, methods to create these PDMS composites are reviewed and classified. It is highlighted how the composites can be applied to a range of substrates, from micrometer-scale, temperature-sensitive optical fibers to centimeter-scale curved and planar surfaces. The resulting composites have enabled all-optical ultrasound imaging of biological tissues both ex vivo and in vivo, with high spatial resolution and with clinically relevant contrast. In addition, the first 3D all-optical pulse-echo ultrasound imaging of ex vivo human tissue, using a PDMS-multiwalled carbon nanotube composite and a fiber-optic ultrasound receiver, is presented. Gold nanoparticle-PDMS and crystal violet-PDMS composites with prominent absorption at one wavelength range for pulse-echo ultrasound imaging and transmission at a second wavelength range for photoacoustic imaging are also presented. Using these devices, images of diseased human vascular tissue with both structural and molecular contrast are obtained. With a broader perspective, literature on recent advances in PDMS microfabrication from different fields is highlighted, and methods for incorporating them into new generations of optical ultrasound generators are suggested.Polydimethylsiloxane (PDMS) composites offer several advantages for optical ultrasound generation via the photoacoustic effect. Here, methods to fabricate PDMS composites are reviewed and their application to substrates of varying sizes and geometries is highlighted. It is demonstrated that certain PDMS composites enable both all-optical ultrasound and photoacoustic imaging of biological tissue with high spatial resolution and clinically relevant contrast.
      PubDate: 2018-01-15T06:13:07.443056-05:
      DOI: 10.1002/adfm.201704919
       
  • Contents: (Adv. Funct. Mater. 3/2018)
    • PubDate: 2018-01-15T05:49:57.671283-05:
      DOI: 10.1002/adfm.201870018
       
  • Energy Storage: Oriented Multiwalled Organic–Co(OH)2 Nanotubes for
           Energy Storage (Adv. Funct. Mater. 3/2018)
    • Authors: Garrett C. Lau; Nicholas A. Sather, Hiroaki Sai, Elizabeth M. Waring, Elad Deiss-Yehiely, Leonel Barreda, Emily A. Beeman, Liam C. Palmer, Samuel I. Stupp
      Abstract: A layered Co(OH)2-organic hybrid material consisting of multi-walled nanotubes with preferred alignment is reported by Samuel I. Stupp and co-workers in article number 1702320. Electrodeposited on conductive substrates, the material functions as energy storage electrode. The molecular structure of the organic component determines the morphology of the hybrid material and its resulting electrochemical performance.
      PubDate: 2018-01-15T05:49:57.188932-05:
      DOI: 10.1002/adfm.201870019
       
  • Tissue Regeneration: A Multifunctional Polymeric Periodontal Membrane with
           Osteogenic and Antibacterial Characteristics (Adv. Funct. Mater. 3/2018)
    • Authors: Amir Nasajpour; Sahar Ansari, Chiara Rinoldi, Afsaneh Shahrokhi Rad, Tara Aghaloo, Su Ryon Shin, Yogendra Kumar Mishra, Rainer Adelung, Wojciech Swieszkowski, Nasim Annabi, Ali Khademhosseini, Alireza Moshaverinia, Ali Tamayol
      Abstract: In article 1703437, Alireza Moshaverinia, Ali Tamayol, and co-workers develop a nano-enabled membrane for the treatment of periodontitis-induced bone loss. The membranes are formed by electrospinning of poly(caprolactone) containing zinc oxide nanoparticles. The outcome of the fabrication process are nanofibrous membranes embedded with ZnO nanoparticles. The membranes prevent infection and direct tissue regeneration in vivo.
      PubDate: 2018-01-15T05:49:57.12668-05:0
      DOI: 10.1002/adfm.201870021
       
  • Masthead: (Adv. Funct. Mater. 3/2018)
    • PubDate: 2018-01-15T05:49:57.055975-05:
      DOI: 10.1002/adfm.201870017
       
  • Microbatteries: Self-Supported 3D Array Electrodes for Sodium
           Microbatteries (Adv. Funct. Mater. 3/2018)
    • Authors: Jiangfeng Ni; Liang Li
      Abstract: Miniaturized on-chip high power microbatteries are extremely desirable for autonomous microelectronics but require a challenging three-dimensional (3D) battery design. In article number 1704880, Jianfeng Ni and Liang Li summarize the state-of-the-art progress in the design and application of 3D arrays for sodium microbatteries, and highlight the importance of integrating novel concepts into 3D electrode fabrication, characterization, and modeling to meet practical requirements.
      PubDate: 2018-01-15T05:49:56.589054-05:
      DOI: 10.1002/adfm.201870015
       
  • Solar Cells: PtCoFe Nanowire Cathodes Boost Short-Circuit Currents of
           Ru(II)-Based Dye-Sensitized Solar Cells to a Power Conversion Efficiency
           of 12.29% (Adv. Funct. Mater. 3/2018)
    • Authors: Chin-Cheng (Paul) Chiang; Chang-Yu Hung, Shang-Wei Chou, Jing-Jong Shyue, Kum-Yi Cheng, Pei-Jen Chang, Ya-Yun Yang, Ching-Yen Lin, Ting-Kuang Chang, Yun Chi, Hung-Lung Chou, Pi-Tai Chou
      Abstract: In article number 1703282, Shang-Wei Chou, Yun Chi, Hung-Lung Chou, Pi-Tai Chou, and co-workers describe PtCoFe nanowires with rich {111} facets exhibiting superior I−3 reduction activity in DSSCs (dye-sensitized solar cells). The PRT-22 DSSC using Pt49Co23Fe28 nanowire as cathode shows a certified power conversion efficiency of 12.0%, which surpasses the previous power conversion efficiency (PCE) record of the DSSCs using Ru(II)-based dyes.
      PubDate: 2018-01-15T05:49:51.176719-05:
      DOI: 10.1002/adfm.201870020
       
  • Battery Binders: Highly Stretchable Conductive Glue for High-Performance
           Silicon Anodes in Advanced Lithium-Ion Batteries (Adv. Funct. Mater.
           3/2018)
    • Authors: Lei Wang; Tiefeng Liu, Xiang Peng, Wenwu Zeng, Zhenzhen Jin, Weifeng Tian, Biao Gao, Yinhua Zhou, Paul K. Chu, Kaifu Huo
      Abstract: A highly stretchable conductive glue that functions both as binder and as conductive additive in Si anodes is reported by Yinhua Zhou, Kaifu Huo, and co-workers in article number 1704858. Lithium-ion batteries applying this anode exhibit high cycling stability, large reversible capacity, and high initial coulombic efficiency, making the approach promising for next-generation batteries.
      PubDate: 2018-01-15T05:49:51.118202-05:
      DOI: 10.1002/adfm.201870016
       
  • Achieving a Record Fill Factor for Silicon–Organic Hybrid Heterojunction
           Solar Cells by Using a Full-Area Metal Polymer Nanocomposite Top Electrode
           
    • Authors: Juye Zhu; Xi Yang, Zhenhai Yang, Dan Wang, Pingqi Gao, Jichun Ye
      Abstract: Carrier collection in conventional n-type Si (n-Si)/organic hybrid heterojunction solar cells (HHSCs) is mainly limited by the nonoptimized top grid-electrode and inadequate work function (WF) of the PH1000-type poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). Here, a novel modified metal polymer nanocomposite top electrode (M-MPNTE) is designed to achieve a full-area carrier collection in n-Si/PEDOT:PSS HHSCs. The carrier collection in both lateral and vertical directions is significantly improved by the introduction of an ultrathin Au/MoOx modified layer between 6 nm ultrathin Ag film and AI4083-type PEDOT:PSS layer. In addition, the carrier separation is boosted by the enhanced built-in potential owing to a high WF of M-MPNTE, which also suppresses the carrier recombination at the surface of n-Si. Due to these collaborative improvements, a record fill factor of 80.21% is obtained, which is even comparable to the best value of the traditional Si-based solar cells. With the addition of a MoOx antireflective coating layer on top of M-MPNTE, the short-circuit current density and open-circuit voltage are finally increased to 23.13 mA cm−2 and 621.07 mV, respectively, yielding a power conversion efficiency of 10.82%. The finding suggests a novel strategy for the development of highly efficient HHSCs with ideal carrier transport mechanism.A novel modified nanocomposite electrode is designed to achieve a full-area carrier collection in Si/organic heterojunction solar cells. The carrier collection in both lateral and vertical directions as well as the carrier separation are boosted, resulting in a record fill factor of 80.21%. The finding suggests a strategy for the development of highly efficient solar cells with ideal carrier transport route.
      PubDate: 2018-01-15T05:34:11.537971-05:
      DOI: 10.1002/adfm.201705425
       
  • Space-Charge-Stabilized Ferroelectric Polarization in Self-Oriented
           Croconic Acid Films
    • Authors: Laigui Hu; Rui Feng, Jiao Wang, Zilong Bai, Wei Jin, Liuqun Zhang, Qing-Miao Nie, Zhi-Jun Qiu, Pengfei Tian, Chunxiao Cong, Lirong Zheng, Ran Liu
      Abstract: Great progress has been made recently in molecular ferroelectrics with properties even comparable to those of inorganic ferroelectrics. However, it is difficult to develop basic thin films and devices for practical applications since most molecular ferroelectrics are uniaxial. The single polar axes of crystallites inside their films, if available, are usually oriented randomly. These can induce the components without contribution to ferroelectric polarization and a large depolarization electric field to suppress polarization. In this work, it is demonstrated that uniaxial croconic acid films in two-terminal devices, deposited by thermal evaporation, can show effective ferroelectric polarization and nonvolatile memory switching behavior with small coercive fields of 11–30 kV cm−1. The polar c-axes in thick crystalline films (>500 nm) are found to be self-oriented nearly at a desired direction. With the assistance of trapped charges, stable ferroelectric polarization can be achieved, in spite of the existence of nonferroelectric components. These may pave a way to utilize uniaxial molecular ferroelectrics for various applications, such as gate dielectrics, electrets, and memory devices.Molecular ferroelectric croconic acid films and two-terminal devices are demonstrated. Crystallites in the films with thickness of>500 nm can show dominant preferential orientation along the direction perpendicular to substrates. This leads to stable ferroelectric polarization and small coercive electric fields (11–30 kV cm−1) in devices with the assistance of space charges induced by injection and moisture adsorption.
      PubDate: 2018-01-15T05:33:39.209707-05:
      DOI: 10.1002/adfm.201705463
       
  • Circular Gold Nanodisks with Synthetically Tunable Diameters and
           Thicknesses
    • Authors: Ximin Cui; Feng Qin, Qifeng Ruan, Xiaolu Zhuo, Jianfang Wang
      Abstract: 2D or pseudo-2D plasmonic Au nanocrystals, such as circular Au nanodisks, possess unique plasmonic properties. Circular Au nanodisks not only possess two large surfaces with circular symmetry but also exhibit the wide tunability for their plasmon resonance. However, the lack of effective synthetic methods for producing size-tunable and monodispersed circular Au nanodisks hinders further studies on their properties and applications. Herein, the synthesis of uniformly sized circular Au nanodisks with synthetically tunable diameters and thicknesses is reported. By performing mild anisotropic oxidation on pregrown Au nanoplates with different thicknesses, the thicknesses of the obtained nanodisks are varied from ≈10 nm to ≈50 nm. The nanodisk diameters are tailored from ≈50 nm to ≈150 nm by controlling the oxidation time. Moreover, both homodimers and heterodimers made of circular Au nanodisks are constructed using molecular linkers. They exhibit rich plasmon modes. In particular, dark multipolar plasmon resonance modes can be excited and observed in the asymmetric heterodimers. Such circular Au nanodisks with controllable sizes, large atomically flat surfaces, and a dominant dipolar plasmon mode are ideal building blocks for constructing plasmonic assemblies and plasmon-coupled systems with desired plasmonic properties and functions.Colloidal circular Au nanodisks with controllable diameters and thicknesses are synthesized. Their in-plane dipolar plasmon resonance can be synthetically varied from the visible to near-infrared region. Homodimers and heterodimers in different geometrical configurations are assembled out of the circular Au nanodisks with different thicknesses. They display rich plasmon modes that can rarely be seen on other dimeric metal nanostructures.
      PubDate: 2018-01-15T05:33:01.719875-05:
      DOI: 10.1002/adfm.201705516
       
  • Wearable Supercapacitors Printed on Garments
    • Authors: Seong-Sun Lee; Keun-Ho Choi, Se-Hee Kim, Sang-Young Lee
      Abstract: Electronic garments have garnered considerable attention as a core technology for the upcoming wearable electronics era. To enable ubiquitous operation of electronic garments, they must be monolithically integrated with rechargeable power sources. Here, inspired by printing-assisted aesthetic clothing designs, a new class of wearable supercapacitors (SCs) is demonstrated that can be directly printed on T-shirts, which look like letters (or symbols) commonly printed on T-shirts. The printed SCs consist of activated carbon/multiwalled carbon nanotube/ionic liquid-based electrodes and ionic liquid/thiol-ene polymer network skeleton/SiO2 nanoparticle-based gel electrolytes. The rheological properties of the electrode/electrolyte pastes are fine-tuned by varying the colloidal network structure, which affects the printing processability and formation of the nanoscale ion/electron conduction channels. To ensure the seamless unitization and design versatility of the printed SCs, the T-shirt is sewn with electroconductive stainless steel (SS) threads prior to the printing process. Onto the SS threads acting as shape-directing current collectors, the electrode/electrolyte pastes are sequentially stencil-printed and sealed with water-proof packaging films. The printed SCs exhibit exceptional form factors, flexibility, and thermal stability. Notably, the SC-printed T-shirts maintain their electrochemical activity upon exposure to laundering, wringing, ironing, and folding, demonstrating their potential and practical applicability as a promising electronic garment technology.Wearable supercapacitors (SCs) printed on T-shirts are demonstrated as a new class of aesthetically unitized power source with exceptional design versatility and flexibility. The SC-printed T-shirts show great potential as an effective/scalable electronic garment platform for the forthcoming wearable electronics era.
      PubDate: 2018-01-15T05:32:11.499284-05:
      DOI: 10.1002/adfm.201705571
       
  • New Strategy for Polysulfide Protection Based on Atomic Layer Deposition
           of TiO2 onto Ferroelectric-Encapsulated Cathode: Toward Ultrastable
           Free-Standing Room Temperature Sodium–Sulfur Batteries
    • Authors: Dingtao Ma; Yongliang Li, Jingbo Yang, Hongwei Mi, Shan Luo, Libo Deng, Chaoyi Yan, Muhammad Rauf, Peixin Zhang, Xueliang Sun, Xiangzhong Ren, Jianqing Li, Han Zhang
      Abstract: The room temperature (RT) sodium–sulfur batteries (Na–S) hold great promise for practical applications including energy storage and conversion due to high energy density, long lifespan, and low cost, as well based on the abundant reserves of both sodium metal and sulfur. Herein, freestanding (C/S/BaTiO3)@TiO2 (CSB@TiO2) electrode with only ≈3 wt% of BaTiO3 additive and ≈4 nm thickness of amorphous TiO2 atomic layer deposition protective layer is rational designed, and first used for RT Na–S batteries. Results show that such cathode material exhibits high rate capability and excellent durability compared with pure C/S and C/S/BaTiO3 electrodes. Notably, this CSB@TiO2 electrode performs a discharge capacity of 524.8 and 382 mA h g−1 after 1400 cycles at 1 A g−1 and 3000 cycles at 2 A g−1, respectively. Such superior electrochemical performance is mainly attributed from the “BaTiO3-C-TiO2” synergetic structure within the matrix, which enables effectively inhibiting the shuttle effect, restraining the volumetric variation and stabilizing the ionic transport interface.Free-standing (C/S/BaTiO3)@TiO2 nanofibers with only ≈3 wt% of BaTiO3 additive and ≈4 nm of amorphous TiO2 nanolayer are used for room temperature sodium–sulfur batteries. Such a unique structure of “BaTiO3-C-TiO2” electrode holds promise for high energy density, long lifespan, and low cost energy storage and conversion systems.
      PubDate: 2018-01-15T05:31:07.266701-05:
      DOI: 10.1002/adfm.201705537
       
  • Self-Propelled Rolled-Up Polyelectrolyte Multilayer Microrockets
    • Authors: Narisu Hu; Mengmeng Sun, Xiankun Lin, Changyong Gao, Bin Zhang, Ce Zheng, Hui Xie, Qiang He
      Abstract: Engineering self-propelled micro-/nanomachines with ultrafast speeds and high towing forces is crucial for the efficient transportation of important objects in key biomedical and environmental applications. In this study, rolled-up nanomembrane technology is used for the first time for the controlled fabrication of layer-by-layer (LbL)-assembled microtubes and the corresponding chemical-powered microrockets. By integrating LbL assembly, microcontact printing, and a rolled-up nanomembrane technique, polyelectrolyte multilayer microplates of different shapes are transformed into well-defined microtubes. Coupled with platinum nanoparticles, the as-prepared microtubes can act as bubble-propelled microrockets with a very rapid speed and a large towing force. As a proof of concept, the rolled LbL microrockets confirm the feasibility of transporting single or multiple cells at high speed. Integrating the rolled-up nanomembrane technology and LbL assembly results in a simple, versatile, and low-cost approach and expands the scope of both polymer multilayer-based multifunctional tubes and artificial machines at the micro-/nanoscale.Self-propelled rolled-up microrockets based on layer-by-layer (LbL) assembly are presented. The self-rolling of polyelectrolyte multilayer microplates, prepared by combining LbL assembly and microcontact printing, produces rolled-up microtubes. Through integrating platinum nanoparticles, the microtubes are transformed into bubble-propelled microrockets. The curling structure of the microrockets yields superfast speeds and large towing forces for transporting single or multiple cells.
      PubDate: 2018-01-15T05:30:36.629302-05:
      DOI: 10.1002/adfm.201705684
       
  • Reconfigurable Swarms of Ferromagnetic Colloids for Enhanced Local
           Hyperthermia
    • Authors: Ben Wang; Kai Fung Chan, Jiangfan Yu, Qianqian Wang, Lidong Yang, Philip Wai Yan Chiu, Li Zhang
      Abstract: Ferromagnetic particles (FMPs) have attracted a large amount of attention for tumor treatment in recent decades in the form of magnetic hyperthermia and thermoablation therapies. Previous research has commonly focused on the improvement of the specific loss power and the increase in the particle concentration to enhance the heating temperature during hyperthermia. Instead of magnetic hyperthermia with passive particles, here a feasible approach of using reconfigurable swarms of ferromagnetic colloidal particles is reported to realize enhanced local hyperthermia. The concentration of the particle swarm can be tuned up to 500% of the original particle concentration via reversible pattern transformation, i.e., shrinking and swelling. The FMP swarms with a controllable pattern size show their potential for directed energy delivery and offer a new strategy for realizing a highly localized heating effect using a low dose of the active FMPs.A reconfigurable ferromagnetic colloidal swarm is developed for enhanced local hyperthermia. The simulation and experimental results indicate that the local heating effects and the spatial resolution of the hyperthermia process can be significantly improved by using a microrobotic swarm.
      PubDate: 2018-01-15T05:29:44.28229-05:0
      DOI: 10.1002/adfm.201705701
       
  • Helical Nanomachines as Mobile Viscometers
    • Authors: Arijit Ghosh; Debayan Dasgupta, Malay Pal, Konstantin I. Morozov, Alexander M. Leshansky, Ambarish Ghosh
      Abstract: A wide variety of applications are envisioned and demonstrated with artificial micro- and nanomachines, ranging from targeted drug or gene delivery, microsurgery, environmental sensing, and many more. Here, it is demonstrated how helical nanomachines can be used to measure and map the local mechanical properties of a complex heterogeneous environment. The positions of the nanomachines are precisely controlled using externally applied magnetic fields, while their instantaneous orientations provide estimation of the viscosity of the surrounding medium with high spatial and temporal accuracy. The measurement technique can be applied to both Newtonian as well as shear thinning media, and all experimental results are in good agreement with the theoretical analysis. It is believed that this novel application of helical nanomachines can be particularly relevant to biophysical studies and microfluidic technologies.Helical nanomachines are maneuvered and positioned in a heterogenous mechanical environment with micrometer scale resolution using externally applied magnetic fields. The orientation dynamics of the machine is used to quantify the local viscosity in real time. This measurement technique is applicable to both Newtonian as well as shear thinning media, and applicable to various biophysical studies and microfluidic technologies.
      PubDate: 2018-01-15T05:28:39.79341-05:0
      DOI: 10.1002/adfm.201705687
       
  • Lithium Tin Sulfide—a High-Refractive-Index 2D Material for
           Humidity-Responsive Photonic Crystals
    • Authors: Katalin Szendrei-Temesi; Olalla Sanchez-Sobrado, Sophia B. Betzler, Katharina M. Durner, Tanja Holzmann, Bettina V. Lotsch
      Abstract: Extending the portfolio of novel stimuli-responsive, high-refractive-index (RI) materials besides titania is key to improve the optical quality and sensing performance of existing photonic devices. Herein, lithium tin sulfide (LTS) nanosheets are introduced as a novel solution processable ultrahigh RI material (n = 2.50), which can be casted into homogeneous thin films using wet-chemical deposition methods. Owing to its 2D morphology, thin films of LTS nanosheets are able to swell in response to changes of relative humidity. Integration of LTS nanosheets into Bragg stacks (BSs) based on TiO2, SiO2, nanoparticles or H3Sb3P2O14 nanosheets affords multilayer systems with high optical quality at an extremely low device thickness of below 1 µm. Owing to the ultrahigh RI of LTS nanosheets and the high transparency of the thin films, BSs based on porous titania as the low-RI material are realized for the first time, showing potential application in light-managing devices. Moreover, the highest RI contrast ever realized in BSs based on SiO2 and LTS nanosheets is reported. Finally, exceptional swelling capability of an all-nanosheet BS based on LTS and H3Sb3P2O14 nanosheets is demonstrated, which bodes well for a new generation of humidity sensors with extremely high sensitivity.Lithium–tin sulfide (LTS) nanosheets are a new optical material featuring an ultrahigh refractive index (RI). Using LTS thin films, photonic crystals based on porous titania as low-refractive-index material are demonstrated and SiO2/LTS Bragg stacks showing the largest RI contrast ever reported. The swelling response of an all-nanosheet Bragg stack is utilized to create humidity sensors with ultrahigh sensitivity.
      PubDate: 2018-01-15T05:28:27.607375-05:
      DOI: 10.1002/adfm.201705740
       
  • Complementary Electromagnetic-Triboelectric Active Sensor for Detecting
           Multiple Mechanical Triggering
    • Authors: Peihong Wang; Ruiyuan Liu, Wenbo Ding, Peng Zhang, Lun Pan, Guozhang Dai, Haiyang Zou, Kai Dong, Cheng Xu, Zhong Lin Wang
      Abstract: With the fast development of integrated circuit technology and internet of things, sensors with multifunctional characteristics are desperately needed. This work presents an integrated electromagnetic-triboelectric active sensor (ETAS) for simultaneous detection of multiple mechanical triggering signals. The good combination of a contact-separation mode triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) realizes the complement of their individual advantages. The theoretical calculation and analysis of EMG and TENG are performed to understand the relationship between their output and the external mechanical signals. The experimental results show that the output voltage of TENG part is suitable to detect the magnitude of the external triggering force with a sensitivity of about 2.01 V N−1. Meanwhile, the output current of EMG part is more appropriate to reflect the triggering velocity and the sensitivity is about 4.3 mA (m s−1)−1. Moreover, both the TENG part and the EMG part exhibit good stabilities after more than 20 000 cycles of force loading and unloading. One ETAS that can record the typing behavior of the finger precisely is demonstrated. In addition, the TENG part can harvest the mechanical energy during typing for possible powering of tiny electronics. This ETAS has promising applications in complex human–machine interface, personal identification, and security system.A function-complementary electromagnetic-triboelectric active sensor is developed. This hybridized sensor consists of a contact-separation mode triboelectric nanogenerator and an electromagnetic generator, which can detect multiple dynamic mechanical triggering signals simultaneously. Therefore, it has promising applications in complex human–machine interface, personal identification, and security system.
      PubDate: 2018-01-15T05:28:02.808762-05:
      DOI: 10.1002/adfm.201705808
       
  • Mobile Magnetic Nanocatalysts for Bioorthogonal Targeted Cancer Therapy
    • Authors: Marcus Hoop; Ana Sofia Ribeiro, Daniel Rösch, Philipp Weinand, Nuno Mendes, Fajer Mushtaq, Xiang-Zhong Chen, Yang Shen, Carlos Franco Pujante, Josep Puigmartí-Luis, Joana Paredes, Bradley J. Nelson, Ana Paula Pêgo, Salvador Pané
      Abstract: The use of magnetic nanorobots to activate chemotherapeutic prodrugs represents a promising alternative to current chemotherapeutic treatments. Here, a hybrid nanowire (NW) for targeted bioorthogonally driven activation of the latent chemotherapeutic prodrug 5-fluoro-1-propargyl-uracil (Pro-5-FU) in in vitro and in vivo cancer models is proposed. The NWs are composed of magnetic iron (Fe) and palladium (Pd), a known bioorthogonal catalyst. In vitro tests with a cancer cell line showed no significant cytotoxic effect by the NWs. In contrast, NWs combined with Pro-5-FU lead to a significant reduction of cell viability, similarly to the one induced by its active chemotherapeutic counterpart 5-fluorouracil (5-FU). The reduction in cell viability is attributed to the catalytic activation of Pro-5-FU into 5-FU. To demonstrate their targeted therapeutic abilities, magnetic fields are used to attract the FePd NWs to a predefined area within a cultured cancer cell population, causing a local Pro-5-FU activation, and subsequent cell death in this region. As a proof of concept, NWs are injected in cancer tumor xenografts. The intraperitoneal injection of Pro-5-FU significantly retards tumour growth without causing significant side effects. This work presents a novel chemotherapeutic approach combining nanorobotics and bioorthogonal activation of prodrugs as an efficient alternative to conventional chemotherapy.Iron–palladium-based magnetic nanocatalysts are used for bioorthogonally driven targeted cancer therapy. The alloy nanocatalysts exhibit bioorthogonal activity by turning a latent prodrug to an anticancer agent. The therapeutic efficiency is demonstrated both in vitro and in vivo. This study presents a novel cancer therapy approach combining nanotechnology, nanorobotics, and bioorthogonal chemistry as an efficient alternative to conventional chemotherapy approaches.
      PubDate: 2018-01-15T05:27:35.0026-05:00
      DOI: 10.1002/adfm.201705920
       
  • Fuel-Free Nanocap-Like Motors Actuated Under Visible Light
    • Authors: Xu Wang; Varun Sridhar, Surong Guo, Nahid Talebi, Albert Miguel-López, Kersten Hahn, Peter A. Aken, Samuel Sánchez
      Abstract: The motion of nanomotors triggered by light sources will provide new alternative routes to power nanoarchitectures without the need of chemical fuels. However, most light-driven nanomotors are triggered by UV-light, near infrared reflection, or laser sources. It is demonstrated that nanocap shaped Au/TiO2 nanomotors (175 nm in diameter) display increased Brownian motion in the presence of broad spectrum visible light. The motion results from the surface plasmon resonance effect leading to self-electrophoresis between the Au and TiO2 layers, a mechanism called plasmonic photocatalytic effect in the field of photocatalysis. This mechanism is experimentally characterized by electron energy loss spectroscopy, energy-filtered transmission electron microscopy, and optical video tracking. This mechanism is also studied in a more theoretical manner using numerical finite-difference time-domain simulations. The ability to power nanomaterials with visible light may result in entirely new applications for externally powered micro/nanomotors.A cap-shaped Au/TiO2 nanomotors are presented that show enhanced Brownian motion under visible light in water in a fuel-free manner. The motion results from the surface plasmon resonance effect leading to self-electrophoresis between the Au and TiO2 layers. This mechanism is named plasmonic photocatalytic effect, demonstrated experimentally and by finite-difference time-domain simulations.
      PubDate: 2018-01-15T05:26:56.994879-05:
      DOI: 10.1002/adfm.201705862
       
  • Graphene Microstrip Patch Ultrawide Band Antennas for THz Communications
    • Authors: Mojtaba Dashti; J. David Carey
      Abstract: Future generation local communication systems will need to employ THz frequency bands capable of transferring sizable amounts of data. Current THz technology via electrical excitation is limited by the upper limits of device cutoff frequencies and by the lower limits of optical transitions in quantum confined structures. Current metallic THz antennas require high power to overcome scattering losses and tend to have low antenna efficiency. It is shown here via calculation and simulation that graphene can sustain electromagnetic propagation at THz frequencies via engineering the intra- and interband contributions to the dynamical conductivity to produce a variable surface impedance microstrip antenna with a several hundred GHz bandwidth. The optimization of a circular graphene microstrip patch antenna on silicon with an optimized return loss of −26 dB, a −10 dB bandwidth of 504 GHz, and an antenna efficiency of −3.4 dB operating at a frequency of 2 THz is reported. An improved antenna efficiency of −0.36 dB can be found at 3.5 THz but is accompanied by a lower bandwidth of about 200 GHz. Such large bandwidths and antenna efficiencies offer significant hope for graphene-based flexible directional antennas that can be employed for future THz local device-to-device communications.Graphene is shown to sustain electromagnetic wave propagation at THz frequencies and leads to ultrawide band antennas of several hundred GHz bandwidth and is a route to bridge the so-called THz gap. Such a technology will open up the possibility of efficient data transfer at high rates for local device-to-device communications on flexible and conformal substrates.
      PubDate: 2018-01-15T05:25:06.929424-05:
      DOI: 10.1002/adfm.201705925
       
  • Janus Microdimer Surface Walkers Propelled by Oscillating Magnetic Fields
    • Authors: Tianlong Li; Anning Zhang, Guangbin Shao, Mengshi Wei, Bin Guo, Guangyu Zhang, Longqiu Li, Wei Wang
      Abstract: Recent strides in micro- and nanofabrication technologies have enabled researchers to design and develop micro- and nanoscale robotic systems with enhanced power, functionality, and versatility. Because of their capability of remote actuation and navigation, synthetic micro- and nanomotors powered by oscillating magnetic fields have recently gained considerable attention. In this article, a new type of magnetic surface walker that can achieve speeds of up to 18.6 µm s−1 (≈4 body length s−1) in an oscillating magnetic field operated at 25 Hz and ≈2.7 mT is reported. Two magnetic Janus microspheres spontaneously form a microdimer via magnetic dipolar interactions, and this microdimer rolls its two “feet” back and forth in an alternating fashion. In addition to propulsion, the oscillating magnetic field can also precisely steer these surface walkers through complicated structures, and an extensive discussion of their performance in various experimental conditions is provided. The reported propulsion mechanism opens new possibilities for the design of remotely actuated microrobots for a wide range of applications.Magnetically coated Janus microspheres align and bind into dimers in an oscillating magnetic field, and leap into directional motion by alternating their two spheres back and forth in an asymmetric fashion dictated by the underlying substrate. The speed and directionality of these surface microwalkers can be precisely manipulated, and they circumvent and overcome obstacles, demonstrating their potential usefulness.
      PubDate: 2018-01-15T05:24:49.624165-05:
      DOI: 10.1002/adfm.201706066
       
  • Nanomotor-Based Strategy for Enhanced Penetration across Vasculature Model
    • Authors: Fei Peng; Yongjun Men, Yingfeng Tu, Yongming Chen, Daniela A. Wilson
      Abstract: Here the first nanomotor-based strategy is reported to effectively cross tumor vasculature endothelium. The designed nanomotors are based on (poly(ethylene glycol)-b-polystyrene and poly(acrylic acid)-b-polystyrene) building blocks, which further self-assemble into polymersomes of tunable sizes (100, 300 nm). The polymersomes are readily loaded with hydrophilic model drug into the aqueous compartment. A catalytic platinum cap is then partially deposited on the surface of the polymersome via electron beam evaporation, resulting in a polymersome Janus nanomotor. In a tumor vasculature model, these cargo-loaded polymersome nanomotors demonstrate enhanced penetration across the endothelium.A polymersome-based Janus nanomotor is developed with a versatile fabrication approach. With its hollow cavity, the polymersome nanomotor is capable of carrying model drug cargo. The nanomotor exhibits enhanced penetration across the tumor vasculature model and capable of release cargo on demand. The nanomotor provides a promising platform for active cargo delivery using the enhanced permeability and retention (EPR) strategy.
      PubDate: 2018-01-15T05:24:21.254756-05:
      DOI: 10.1002/adfm.201706117
       
  • Robust Fabrication of Nonstick, Noncorrosive, Conductive Graphene-Coated
           Liquid Metal Droplets for Droplet-Based, Floating Electrodes
    • Authors: Yuzhen Chen; Tingjiao Zhou, Yaoyao Li, Lifei Zhu, Stephan Handschuh-Wang, Deyong Zhu, Xiaohu Zhou, Zhou Liu, Tiansheng Gan, Xuechang Zhou
      Abstract: Nontoxic liquid metals (conductive materials in a liquid state at room temperature) are an emerging class of materials for applications ranging from soft electronics and robotics to medical therapy and energy devices. Their sticky and corrosive properties, however, are becoming more of a critical concern for circuits and devices containing other metals as these are easily destroyed or contaminated by the liquid metals. Herein, a feasible method for fabricating highly conductive graphene-coated liquid metal (GLM) droplets is reported and their application as nonstick, noncorrosive, movable, soft contacts for electrical circuits is demonstrated. The as-prepared GLM droplets consist of a liquid-phase soft core of liquid metal and a slippery outer layer of graphene sheets. These structures address the issue of simultaneous control of the wettability and conductivity of a soft electronic contact by combining extraordinary properties, i.e., nonstick, noncorrosive, yet exhibiting high electronic conductivity while in contact with metal substrates, e.g., Au, Cu, Ag, and Ni. As proof-of-concept, the as-prepared GLM droplets are demonstrated as floating electrodes for movable, recyclable electronic soft contacts in electrical circuits.Highly conductive graphene-coated liquid metal (GLM) droplets are fabricated and used as nonstick, noncorrosive, movable, soft electric contacts for droplet-based soft electronics. The GLM droplets consist of a liquid-phase soft core of liquid metal and a slippery outer layer of graphene sheets, which well addresses the issue of simultaneously controlling the wettability and conductivity of liquid metal droplets.
      PubDate: 2018-01-15T05:23:58.838866-05:
      DOI: 10.1002/adfm.201706277
       
  • N-Doping and Defective Nanographitic Domain Coupled Hard Carbon Nanoshells
           for High Performance Lithium/Sodium Storage
    • Authors: Shifei Huang; Zhiping Li, Bo Wang, Jiujun Zhang, Zhangquan Peng, Ruijuan Qi, Jing Wang, Yufeng Zhao
      Abstract: Hard carbons (HCs) possess high lithium/sodium storage capacities, which however suffer from low electric conductivity and poor ion diffusion kinetics. An efficient structure design with appropriate heteroatoms doping and optimized graphitic/defective degree is highly desired to tackle these problems. This work reports a new design of N-doped HC nanoshells (N-GCNs) with homogeneous defective nanographite domains, fabricated through the prechelation between Ni2+ and chitosan and subsequent catalyst confined graphitization. The as-prepared N-GCNs deliver a high reversible lithium storage capacity of 1253 mA h g−1, with outstanding rate performance (175 mA h g−1 at a high rate of 20 A g−1) and good cycling stability, which outperforms most state-of-the-art HCs. Meanwhile, a high reversible sodium storage capacity of 325 mA h g−1 is also obtained, which stabilizes at 174 mA h g−1 after 200 cycles. Density functional theory calculations are performed to uncover the coupling effect between heteroatom-doping and the defective nanographitic domains down to the atomic scale. The in situ Raman analysis reveals the “adsorption mechanism” for sodium storage and the “adsorption–intercalation mechanism” for lithium storage of N-GCNs.A new design of N-doped hard carbons (HC) nanoshells (N-GCNs) with homogeneous defective nanographite domains, fabricated through a through the prechelation between Ni2+ and chitosan and subsequent catalyst confined graphitization is reported. The as-prepared N-GCNs deliver a high reversible lithium/sodium storage capacity with outstanding rate performance and good cycling stability, which outperforms most state-of-the-art HCs.
      PubDate: 2018-01-15T05:23:15.375305-05:
      DOI: 10.1002/adfm.201706294
       
  • Time-Resolved Studies of Energy Transfer in Thin Films of Green and Red
           Fluorescent Proteins
    • Authors: Joanna M. Zajac; Marcel Schubert, Thomas Roland, Changmin Keum, Ifor D. W. Samuel, Malte C. Gather
      Abstract: Biologically derived fluorescent proteins are attractive candidates for lasing and sensing due to their excellent optical properties, including their high quantum yield, spectral tunability, and robustness against concentration quenching. Here, a time-resolved study of the fluorescence dynamics of protein thin films is reported for the enhanced green fluorescent protein (EGFP), the red-emitting tandem-dimer protein tdTomato, and blends of EGFP and tdTomato. The exciton dynamics are characterized by using spectrally and time-resolved measurements of fluorescence and a threefold reduction in lifetime is observed when going from solution to thin film, down to 1 and 0.6 ns for EGFP and tdTomato, respectively. This finding is attributed to a dipole–dipole nonradiative Förster resonant energy transfer (FRET) in solid state. The temporal characteristics of FRET in blended thin films are also studied and increased nonradiative transfer rates are found. Finally, efficient sensitization of a semiconductor surface with a protein thin film is reported. Such a configuration may have important implications for energy harvesting in hybrid organic–inorganic solar cells and other hybrid optoelectronic devices.The fluorescence dynamics of thin films of enhanced green fluorescent protein (EGFP), the red-emitting tandem-dimer protein tdTomato, and blends of EGFP and tdTomato are studied by streak camera measurements and photon counting. Fluorescent proteins are attractive candidates for solid-state lasing and sensing due to their excellent optical properties, including their high quantum yield, spectral tunability, and robustness against concentration quenching.
      PubDate: 2018-01-15T05:22:38.250043-05:
      DOI: 10.1002/adfm.201706300
       
  • Fluorinated and Alkylthiolated Polymeric Donors Enable both Efficient
           Fullerene and Nonfullerene Polymer Solar Cells
    • Authors: Guangjun Zhang; Xiaopeng Xu, Zhaozhao Bi, Wei Ma, Dongsheng Tang, Ying Li, Qiang Peng
      Abstract: In this work, four donor (D)–acceptor (A) copolymers based on benzodithiophene (BDT) and benzothiadiazole (BT) with different alkylthiolated and/or fluorinated side chains are developed for efficient fullerene and nonfullerene polymer solar cells (PSCs). The synergistic effect of sulfuration and fluorination on the optical absorption, energy level, crystallinity, carrier mobility, blend morphology, and photovoltaic performance is investigated systematically. By incorporating sulfur atoms onto the side chains, a little blueshifted but significantly increased absorption can be obtained for PBDTS-FBT compared to PBDT-FBT. On the other side, a little more blueshifted but much stronger absorption and much lower-lying highest occupied molecular orbital (HOMO) level can be realized for PBDTF-FBT when introducing fluorine atoms instead of sulfur atoms. With the combination of both fluorination and sulfuration strategies, PBDTS-FBT exhibits the best absorption ability, lowest HOMO energy level, and highest crystallinity, which make PBDTSF-FBT devices show the highest power conversion efficiency (PCE) of 10.69% in fullerene PSCs and 11.66% in nonfullerene PSCs. The PCE of 11.66% is the best value for PSCs based on BT-containing copolymer donors reported so far. The results indicate that fluorination and sulfuration have a synergistically positive effect on the performance of D–A photovoltaic copolymers and their solar cell devices.With the combination of fluorination and sulfuration strategies, new benzodithiophene (BDT)–benzothiadiazole (BT) copolymer donors are developed for improving the optical absorption, energy level, carrier mobility, and blend morphology. The fabricated fullerene and nonfullerene polymer solar cells exhibit high power conversion efficiencies of 10.69% and 11.66%.
      PubDate: 2018-01-15T05:22:24.834497-05:
      DOI: 10.1002/adfm.201706404
       
  • Self-Supported 3D Array Electrodes for Sodium Microbatteries
    • Authors: Jiangfeng Ni; Liang Li
      Abstract: The ever-increasing demand for autonomous microelectronic devices necessitates on-chip miniature energy storage systems such as microbatteries. Conventional microbatteries adopt planar thin-film electrodes that display limited areal energy and power due to their undesired coupling. To achieve high energy and power simultaneously, employment of 3D array electrodes has proven indispensable. Adoption of 3D electrodes has become a fashionable trend in lithium microbatteries during the last decade. This trend also occurs in sodium batteries, which are an important alternative to the current lithium system owing to the potentially high power and wide availability of sodium. In this perspective, state-of-the-art progress in design and application of 3D arrays for sodium microbatteries are summarized. Specifically, emphasis is placed on material strategies to efficiently address the intrinsic limitations of pristine arrays such as transportation, activity, and stability. Future challenges and prospects in this field are also discussed, and the importance of integrating novel concepts into 3D electrode fabrication, characterization, and modeling to meet practical requirements is highlighted.Self-supported 3D electrode arrays offer the advantage to improve the areal energy and power simultaneously, and thus are suitable for microbatteries. In this perspective, the cutting-edge advancements in design, fabrication, and modification of sodium array electrodes for microbatteries are summarized. Specific emphasis is placed on materials strategies that are capable of tailoring the property and electrochemistry of array electrodes.
      PubDate: 2017-11-29T02:16:28.44596-05:0
      DOI: 10.1002/adfm.201704880
       
  • Fish-Microarray: A Miniaturized Platform for Single-Embryo High-Throughput
           Screenings
    • Authors: Anna A. Popova; Daniel Marcato, Ravindra Peravali, Ilona Wehl, Ute Schepers, Pavel A. Levkin
      Abstract: Small molecule high-throughput screenings are essential for the fields of drug discovery and toxicology. Such screenings performed on whole animals are more physiologically relevant leading to more predictive results. However, due to challenges in automation, high costs and absence of miniaturized solutions for animal-based experiments, high throughput screenings based on animal models are still in its infancy. Here a platform for miniaturized high throughput whole-organism screenings is presented. The new platform is based on patterns of hydrophilic spots separated by superhydrophobic borders. The difference in wettability of spots and borders generates the effect of discontinuous dewetting and allows for formation of arrays of microdroplets that incorporate single fish embryos. Due to the flat border-less nature of the platform, the system is compatible with single-step collection of embryos and pipetting-free parallel addition of chemical libraries using the “sandwiching method.” The system is miniaturized and allows for incubation of embryos in volumes as low as 5 µL. Finally, the platform realizes surface tension based immobilization of single embryos inside of each microcompartment and permits high-throughput microscopic analysis directly on the platform. Thus, this method combines the advantages of microarrays, such as high-throughput and simplicity, with the power of in vivo experiments.A platform for miniaturized high-throughput whole-organism screenings is presented. The Droplet-Microarray platform is based on patterns of hydrophilic spots separated by superhydrophobic regions and allows for spontaneous formation of arrays of microdroplets incorporating single zebrafish embryos. The system allows for compound screening of embryos in volumes as low as 5 µL and microscopic analysis directly on the platform.
      PubDate: 2017-11-28T03:28:49.672418-05:
      DOI: 10.1002/adfm.201703486
       
  • Mussel-Inspired Adhesive and Conductive Hydrogel with Long-Lasting
           Moisture and Extreme Temperature Tolerance
    • Authors: Lu Han; Kezhi Liu, Menghao Wang, Kefeng Wang, Liming Fang, Haiting Chen, Jie Zhou, Xiong Lu
      Abstract: Conductive hydrogels are a promising class of materials to design bioelectronics for new technological interfaces with human body, which are required to work for a long-term or under extreme environment. Traditional hydrogels are limited in short-term usage under room temperature, as it is difficult to retain water under cold or hot environment. Inspired by the antifreezing/antiheating behaviors from nature, and based on mussel chemistry, an adhesive and conductive hydrogel is developed with long-lasting moisture lock-in capability and extreme temperature tolerance, which is formed in a binary-solvent system composed of water and glycerol. Polydopamine (PDA)-decorated carbon nanotubes (CNTs) are incorporated into the hydrogel, which assign conductivity to the hydrogel and serve as nanoreinforcements to enhance the mechanical properties of the hydrogel. The catechol groups on PDA and viscous glycerol endow the hydrogel with high tissue adhesiveness. Particularly, the hydrogel is thermal tolerant to maintain all the properties under extreme wide tempreature spectrum (−20 or 60 °C) or stored for a long term. In summary, this mussel-inspired hydrogel is a promising material for self-adhesive bioelectronics to detect biosignals in cold or hot environments, and also as a dressing to protect skin from injuries related to frostbites or burns.A mussel-inspired carbon-nanotube-incorporated conductive hydrogel is developed, which uses glycerol–water as a binary solvent in the polymer network. Thus, the hydrogel can maintain its excellent conductivity, super toughness, and tissue-adhesiveness at extreme temperature. The hydrogel may be a promising material for flexible bioelectronics survival under harsh environments.
      PubDate: 2017-11-28T03:22:23.923431-05:
      DOI: 10.1002/adfm.201704195
       
  • Highly Stretchable Conductive Glue for High-Performance Silicon Anodes in
           Advanced Lithium-Ion Batteries
    • Authors: Lei Wang; Tiefeng Liu, Xiang Peng, Wenwu Zeng, Zhenzhen Jin, Weifeng Tian, Biao Gao, Yinhua Zhou, Paul K. Chu, Kaifu Huo
      Abstract: Binder plays a key role in maintaining the mechanical integrity of electrodes in lithium-ion batteries. However, the existing binders typically exhibit poor stretchability or low conductivity at large strains, which are not suitable for high-capacity silicon (Si)-based anodes undergoing severe volume changes during cycling. Herein, a novel stretchable conductive glue (CG) polymer that possesses inherent high conductivity, excellent stretchablity, and ductility is designed for high-performance Si anodes. The CG can be stretched up to 400% in volume without conductivity loss and mechanical fracture and thus can accommodate the large volume change of Si nanoparticles to maintain the electrode integrity and stabilize solid electrolyte interface growth during cycling while retaining the high conductivity, even with a high Si mass loading of 90%. The Si-CG anode has a large reversible capacity of 1500 mA h g−1 for over 700 cycles at 840 mA g−1 with a large initial Coulombic efficiency of 80% and high rate capability of 737 mA h g−1 at 8400 mA g−1. Moreover, the Si-CG anode demonstrates the highest achieved areal capacity of 5.13 mA h cm−2 at a high mass loading of 2 mg cm−2. The highly stretchable CG provides a new perspective for designing next-generation high-capacity and high-power batteries.Highly stretchable conductive glue is designed for high-performance Si anodes. The glue has dual functions as a binder and conducting additive and can be stretched up to 400% in volume without conductivity loss and mechanical fracture. The Si anode comprised of Si nanoparticles and the conductive glue exhibits high cycling stability, large reversible capacity, and high initial Coulombic efficiency.
      PubDate: 2017-11-27T07:17:46.134151-05:
      DOI: 10.1002/adfm.201704858
       
  • Photoswitchable Ultrafast Transactivator of Transcription (TAT) Targeting
           Effect for Nanocarrier-Based On-Demand Drug Delivery
    • Authors: Junxia Wang; Song Shen, Dongdong Li, Changyou Zhan, Youyong Yuan, Xianzhu Yang
      Abstract: Nanocarriers with intelligent transactivator of transcription (TAT) targeting properties are of particular interest for on-demand drug delivery in the field of precision nanomedicine. Nevertheless, the key challenge of this strategy is the slowness of activating TAT peptide at the targeted tissue. As a proof-of-concept, polymeric micelles STAT-NPIR&DOX with photoswitchable ultrafast TAT targeting effect are designed and explored. The hydrophilic shell of STAT-NPIR&DOX consists of a TAT-functionalized short-chain poly(ethylene glycol) and a thermoresponsive long-chain polyphosphoester (PPE). In nontumor tissue, the TAT peptide of STAT-NPIR&DOX is masked by long-chain PPE to minimize nonspecific uptake of nanocarriers. Upon near-infrared (NIR) photoactivation, the TAT peptide is ultrafastly reexposed (within 60 s) via the collapse of thermoresponsive PPE, resulting in significantly enhanced cellular uptake of nanocarrier by tumor cells. Such photoswitchable TAT targeting effect efficiently avoids nonspecific uptake by nontumor cells and enhances tumor cell uptake, achieving tumor-specific on-demand drug delivery and superior anticancer efficacy. This approach using NIR light-induced TAT targeting effect can be extended to a variety of applications for on-demand drug delivery, which also provides new avenues for phototargeted drug delivery.Polymeric nanocarriers STAT-NPIR&DOX with photoswitchable ultrafast transactivator of transcription (TAT) targeting effect are explored for on-demand drug delivery. The TAT peptide of STAT-NPIR&DOX is masked by thermoresponsive polymer to minimize nonspecific uptake. Upon near-infrared irradiation, the collapse of this thermoresponsive polymer induces TAT peptide ultrafast reexposure and then realizes the photoswitchable targeting effect for on-demand drug delivery and improves anticancer efficacy.
      PubDate: 2017-11-27T07:16:16.542952-05:
      DOI: 10.1002/adfm.201704806
       
  • Influence of Blend Morphology and Energetics on Charge Separation and
           Recombination Dynamics in Organic Solar Cells Incorporating a Nonfullerene
           Acceptor
    • Authors: Hyojung Cha; Scot Wheeler, Sarah Holliday, Stoichko D. Dimitrov, Andrew Wadsworth, Hyun Hwi Lee, Derya Baran, Iain McCulloch, James R. Durrant
      Abstract: Nonfullerene acceptors (NFAs) in blends with highly crystalline donor polymers have been shown to yield particularly high device voltage outputs, but typically more modest quantum yields for photocurrent generation as well as often lower fill factors (FF). In this study, we employ transient optical and optoelectronic analysis to elucidate the factors determining device photocurrent and FF in blends of the highly crystalline donor polymer PffBT4T-2OD with the promising NFA FBR or the more widely studied fullerene acceptor PC71BM. Geminate recombination losses, as measured by ultrafast transient absorption spectroscopy, are observed to be significantly higher for PffBT4T-2OD:FBR blends. This is assigned to the smaller LUMO-LUMO offset of the PffBT4T-2OD:FBR blends relative to PffBT4T-2OD:PC71BM, resulting in the lower photocurrent generation efficiency obtained with FBR. Employing time delayed charge extraction measurements, these geminate recombination losses are observed to be field dependent, resulting in the lower FF observed with PffBT4T-2OD:FBR devices. These data therefore provide a detailed understanding of the impact of acceptor design, and particularly acceptor energetics, on organic solar cell performance. Our study concludes with a discussion of the implications of these results for the design of NFAs in organic solar cells.Charge separation and recombination dynamics in relation to film morphology and energetics are reported in nonfullerene-based PffBT4T-2OD:FBR solar cell. PffBT4T-2OD shows efficient exciton diffusion to the interface between the electron donors and the acceptors. Its small energetic offset explains relatively lower current density and fill factor correlated with geminated recombination and field-dependent photogeneration.
      PubDate: 2017-11-27T02:56:44.543192-05:
      DOI: 10.1002/adfm.201704389
       
  • Designing a High-Performance Lithium–Sulfur Batteries Based on Layered
           Double Hydroxides–Carbon Nanotubes Composite Cathode and a
           Dual-Functional Graphene–Polypropylene–Al2O3 Separator
    • Authors: Jang-Yeon Hwang; Hee Min Kim, Subeom Shin, Yang-Kook Sun
      Abstract: Designing an optimum cell configuration that can deliver high capacity, fast charge–discharge capability, and good cycle retention is imperative for developing a high-performance lithium–sulfur battery. Herein, a novel lithium–sulfur cell design is proposed, which consists of sulfur and magnesium–aluminum-layered double hydroxides (MgAl-LDH)–carbon nanotubes (CNTs) composite cathode with a modified polymer separator produced by dual side coating approaches (one side: graphene and the other side: aluminum oxides). The composite cathode functions as a combined electrocatalyst and polysulfide scavenger, greatly improving the reaction kinetics and stabilizing the Coulombic efficiency upon cycling. The modified separator enhances further Li+-ion or electron transport and prevents undesirable contact between the cathode and dendritic lithium on the anode. The proposed lithium–sulfur cell fabricated with the as-prepared composite cathode and modified separator exhibits a high initial discharge capacity of 1375 mA h g−1 at 0.1 C rate, excellent cycling stability during 200 cycles at 1 C rate, and superior rate capability up to 5 C rate, even with high sulfur loading of 4.0 mg cm−2. In addition, the findings that found in postmortem chracterization of cathode, separator, and Li metal anode from cycled cell help in identifying the reason for its subsequent degradation upon cycling in Li–S cells.The enhanced lithium–sulfur cell design including a MgAl-LDH@CNT-S composite cathode and a DF-GPA separator is proposed. By improving lithium–sulfur redox reactions and minimizing the risk of internal short circuit, this cell configuration enables to yield superior rate capability up to 5 C rate and excellent long-term cycling stability even with high sulfur loading in the electrode of 4.0 mg cm−2.
      PubDate: 2017-11-23T09:38:18.127939-05:
      DOI: 10.1002/adfm.201704294
       
  • Novel Eco-Friendly Starch Paper for Use in Flexible, Transparent, and
           Disposable Organic Electronics
    • Authors: Heejeong Jeong; Seolhee Baek, Singu Han, Hayeong Jang, Se Hyun Kim, Hwa Sung Lee
      Abstract: An eco-friendly biodegradable starch paper is introduced for use in next-generation disposable organic electronics without the need for a planarizing layer. The starch papers are formed by starch gelatinization using a very small amount of 0.5 wt% polyvinyl alcohol (PVA), a polymer that bound to the starch, and 5 wt% of a crosslinker that bound to the PVA to improve mechanical properties. This process minimizes the additions of synthetic materials. The resultant starch paper provides a remarkable mechanical strength and stability under repeated movements. Robustness tests using various chemical solvents are conducted by immersing the starch paper for 6 h. Excellent nonpolar solvent stabilities are observed. They are important for the manufacture of organic electronics that use nonpolar solution processes. The applicability of the starch paper as a flexible substrate is tested by fabricating flexible organic transistors using pentacene, dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene, and poly(dimethyl-triarylamine) using both vacuum and solution processes. Electrically well-behaved device performances are identified. Finally, the eco-friendly biodegradability is verified by subjecting the starch paper to complete degradation by fungi in fishbowl water over 24 d. These developments illuminate new research areas in the field of biodegradable green electronics, enabling the development of extremely low-cost electronics.Eco-friendly biodegradable starch paper for disposable organic electronics is developed that does not require a planarizing layer. This paper applied by starch gelatinization provides a remarkable mechanical strength and chemical robustness in variety of nonpolar solvents, indicating the possibility as a flexible substrate. Finally, biodegradability of the starch paper is verified by the complete decomposition by fungi over 24 d.
      PubDate: 2017-11-23T09:37:25.177015-05:
      DOI: 10.1002/adfm.201704433
       
  • Baby Diaper-Inspired Construction of 3D Porous Composites for Long-Term
           Lithium-Ion Batteries
    • Authors: Huan Huan Wei; Qi Zhang, Yu Wang, Yi Jing Li, Jin Chen Fan, Qun Jie Xu, Yu Lin Min
      Abstract: In this paper, by using the superabsorbent polymers (SAPs) from baby diaper, the 3D porous composites decorated with NiO and Ni nanoparticles (NNSCs) have been prepared via a facile dissolving-freeze drying and subsequent annealing reactions. The porous carbon matrix (PCM) derived from the SAPs also provides a continuous highly conductive network to facilitate the fast charge transfer and form a stable solid electrolyte interface film. Furthermore, NNSC can exhibit the high specific capacity and excellent cycle performance as anode materials for lithium-ion batteries. And more importantly, employing the PCM derived from baby diaper offers a green approach for other energy storage materials.A porous network decorated with NiO nanoparticles is prepared by using the superabsorbent polymers from fresh baby diapers via a facile annealing reaction. The composite exhibits high specific capacity and excellent cycle performance as anode materials for lithium-ion batteries.
      PubDate: 2017-11-23T09:36:54.79312-05:0
      DOI: 10.1002/adfm.201704440
       
  • Ultrafine Nickel-Nanoparticle-Enabled SiO2 Hierarchical Hollow Spheres for
           High-Performance Lithium Storage
    • Authors: Chunjuan Tang; Yuning Liu, Chang Xu, Jiexin Zhu, Xiujuan Wei, Liang Zhou, Liang He, Wei Yang, Liqiang Mai
      Abstract: The high theoretical capacity and natural abundance of SiO2 make it a promising high-capacity anode material for lithium-ion batteries. However, its widespread application is significantly hampered by the intrinsic poor electronic conductivity and drastic volume variation. Herein, a unique hollow structured Ni/SiO2 nanocomposite constructed by ultrafine Ni nanoparticle (≈3 nm) functionalized SiO2 nanosheets is designed. The Ni nanoparticles boost not only the electronic conductivity but also the electrochemical activity of SiO2 effectively. Meanwhile, the hollow cavity provides sufficient free space to accommodate the volume change of SiO2 during repeated lithiation/delithiation; the nanosheet building blocks reduce the diffusion lengths of lithium ions. Due to the synergistic effect between Ni and SiO2, the Ni/SiO2 composite delivers a high reversible capacity of 676 mA h g−1 at 0.1 A g−1. At a high current density of 10 A g−1, a capacity of 337 mA h g−1 can be retained after 1000 cycles.Ultrafine nickel-nanoparticle-functionalized SiO2 hierarchical hollow spheres are synthesized via an in situ reduction approach. The resultant Ni/SiO2 hierarchical hollow spheres manifest high reversible capacity (676 mA h g−1 at 0.1 A g−1), excellent rate capability, and outstanding cyclability (337 mA h g−1 after 1000 cycles at 10 A g−1).
      PubDate: 2017-11-23T09:35:50.892168-05:
      DOI: 10.1002/adfm.201704561
       
  • Light-Responsive Ion-Redistribution-Induced Resistive Switching in Hybrid
           Perovskite Schottky Junctions
    • Authors: Xinwei Guan; Weijin Hu, Md Azimul Haque, Nini Wei, Zhixiong Liu, Aitian Chen, Tom Wu
      Abstract: Hybrid Perovskites have emerged as a class of highly versatile functional materials with applications in solar cells, photodetectors, transistors, and lasers. Recently, there have also been reports on perovskite-based resistive switching (RS) memories, but there remain open questions regarding device stability and switching mechanism. Here, an RS memory based on a high-quality capacitor structure made of an MAPbBr3 (CH3NH3PbBr3) perovskite layer sandwiched between Au and indium tin oxide (ITO) electrodes is reported. Such perovskite devices exhibit reliable RS with an ON/OFF ratio greater than 103, endurance over 103 cycles, and a retention time of 104 s. The analysis suggests that the RS operation hinges on the migration of charged ions, most likely MA vacancies, which reversibly modifies the perovskite bulk transport and the Schottky barrier at the MAPbBr3/ITO interface. Such perovskite memory devices can also be fabricated on flexible polyethylene terephthalate substrates with high bendability and reliability. Furthermore, it is found that reference devices made of another hybrid perovskite MAPbI3 consistently exhibit filament-type switching behavior. This work elucidates the important role of processing-dependent defects in the charge transport of hybrid perovskites and provides insights on the ion-redistribution-based RS in perovskite memory devices.An interface-based hybrid perovskite-based resistive switching (RS) memory device is fabricated and characterized. Because of the elements gradient distribution and movable ionic charges in the perovskite film, the Schottky junction at the MAPbBr3/ITO interface can be reliably modulated, directly giving rise to RS with good endurance and data retention.
      PubDate: 2017-11-23T09:35:21.218768-05:
      DOI: 10.1002/adfm.201704665
       
  • An Ultrathin Flexible 2D Membrane Based on Single-Walled Nanotube–MoS2
           Hybrid Film for High-Performance Solar Steam Generation
    • Authors: Xiangdong Yang; Yanbing Yang, Linna Fu, Mingchu Zou, Zhihao Li, Anyuan Cao, Quan Yuan
      Abstract: Solar steam generation is achieved by localized heating system using various floating photothermal materials. However, the steam generation efficiency is hindered by the difficulty in obtaining a photothermal material with ultrathin structure yet sufficient solar spectrum absorption capability. Herein, for the first time, an ultrathin 2D porous photothermal film based on MoS2 nanosheets and single-walled nanotube (SWNT) films is prepared. The as-prepared SWNT–MoS2 film exhibits an absorption of more than 82% over the whole solar spectrum range even with an ultrathin thickness of ≈120 nm. Moreover, the SWNT–MoS2 film floating on the water surface can generate a sharp temperature gradient due to the localized heat confinement effect. Meanwhile, the ultrathin and porous structure effectively facilitates the fast water vapor escaping, consequently an impressively high evaporation efficiency of 91.5% is achieved. Additionally, the superior mechanical strength of the SWNT–MoS2 film enables the film to be reused for atleast 20 solar illumination cycles and maintains stable water productivity as well as high salt rejection performance. This rational designed hybrid architecture provides a novel strategy for constructing 2D-based nanomaterials for solar energy harvesting, chemical separation, and related technologies.To address the difficulties in obtaining photothermal materials with ultrathin structure yet sufficient solar spectrum absorption capability, an ultrathin and self-floating SWNT–MoS2 hybrid film is designed. As an interfacial heating membrane, this SWNT–MoS2 film shows enhanced steam generation efficiency and superior recycle stability due to the ultrathin and porous structure as well as high mechanical strength.
      PubDate: 2017-11-22T11:02:12.936427-05:
      DOI: 10.1002/adfm.201704505
       
  • Kinetically Controlled Coprecipitation for General Fast Synthesis of
           Sandwiched Metal Hydroxide Nanosheets/Graphene Composites toward Efficient
           Water Splitting
    • Authors: Tang Tang; Wen-Jie Jiang, Shuai Niu, Ning Liu, Hao Luo, Qiang Zhang, Wu Wen, Yu-Yun Chen, Lin-Bo Huang, Feng Gao, Jin-Song Hu
      Abstract: The development of cost-effective and applicable strategies for producing efficient oxygen evolution reaction (OER) electrocatalysts is crucial to advance electrochemical water splitting. Herein, a kinetically controlled room-temperature coprecipitation is developed as a general strategy to produce a variety of sandwich-type metal hydroxide/graphene composites. Specifically, well-defined α-phase nickel cobalt hydroxide nanosheets are vertically assembled on the entire graphene surface (NiCo-HS@G) to provide plenty of accessible active sites and enable facile gas escaping. The tight contact between NiCo-HS and graphene promises effective electron transfer and remarkable durability. It is discovered that Ni doping adjusts the nanosheet morphology to augment active sites and effectively modulates the electronic structure of Co center to favor the adsorption of oxygen species. Consequently, NiCo-HS@G exhibits superior electrocatalytic activity and durability for OER with a very low overpotential of 259 mV at 10 mA cm−2. Furthermore, a practical water electrolyzer demonstrates a small cell voltage of 1.51 V to stably achieve the current density of 10 mA cm−2, and 1.68 V to 50 mA cm−2. Such superior electrocatalytic performance indicates that this facile and manageable strategy with low energy consumption may open up opportunities for the cost-effective mass production of various metal hydroxides/graphene nanocomposites with desirable morphology and competing performance for diverse applications.Kinetically controlled coprecipitation strategy is developed as a general cost-effective strategy to prepare sandwiched metal hydroxide/graphene nanocomposites. Nickel cobalt hydroxide nanosheets vertically assembled on graphene exhibit superior electrocatalytic activity and durability for oxygen evolution reaction, which enables the developed strategy to mass produce a variety of hydroxide/graphene nanocomposites for diverse energy applications.
      PubDate: 2017-11-22T02:34:37.472105-05:
      DOI: 10.1002/adfm.201704594
       
  • Biphase Cobalt–Manganese Oxide with High Capacity and Rate Performance
           for Aqueous Sodium-Ion Electrochemical Energy Storage
    • Authors: Xiaoqiang Shan; Daniel S. Charles, Wenqian Xu, Mikhail Feygenson, Dong Su, Xiaowei Teng
      Abstract: Manganese-based metal oxide electrode materials are of great importance in electrochemical energy storage for their favorable redox behavior, low cost, and environmental friendliness. However, their storage capacity and cycle life in aqueous Na-ion electrolytes is not satisfactory. Herein, the development of a biphase cobalt–manganese oxide (CoMnO) nanostructured electrode material is reported, comprised of a layered MnO2⋅H2O birnessite phase and a (Co0.83Mn0.13Va0.04)tetra(Co0.38Mn1.62)octaO3.72 (Va: vacancy; tetra: tetrahedral sites; octa: octahedral sites) spinel phase, verified by neutron total scattering and pair distribution function analyses. The biphase CoMnO material demonstrates an excellent storage capacity toward Na-ions in an aqueous electrolyte (121 mA h g−1 at a scan rate of 1 mV s−1 in the half-cell and 81 mA h g−1 at a current density of 2 A g−1 after 5000 cycles in full-cells), as well as high rate performance (57 mA h g−1 a rate of 360 C). Electrokinetic analysis and in situ X-ray diffraction measurements further confirm that the synergistic interaction between the spinel and layered phases, as well as the vacancy of the tetrahedral sites of spinel phase, contribute to the improved capacity and rate performance of the CoMnO material by facilitating both diffusion-limited redox and capacitive charge storage processes.In situ X-ray diffraction characterizations of biphase CoMnO material are conducted during electrochemical charge (oxidation) and discharge (reduction) processes, the structure evolution of CoMnO results from Na-ion intercalation and/or deintercalation for aqueous energy storage and is verified by the variations of the lattice constants or layered spacing of a Co1.21Mn1.75O3.72 spinel phase and a MnO2 layered birnessite phase.
      PubDate: 2017-11-22T02:31:03.789391-05:
      DOI: 10.1002/adfm.201703266
       
  • Oriented Multiwalled Organic–Co(OH)2 Nanotubes for Energy Storage
    • Authors: Garrett C. Lau; Nicholas A. Sather, Hiroaki Sai, Elizabeth M. Waring, Elad Deiss-Yehiely, Leonel Barreda, Emily A. Beeman, Liam C. Palmer, Samuel I. Stupp
      Abstract: In energy storage materials, large surface areas and oriented structures are key architecture design features for improving performance through enhanced electrolyte access and efficient electron conduction pathways. Layered hydroxides provide a tunable materials platform with opportunities for achieving such nanostructures via bottom-up syntheses. These nanostructures, however, can degrade in the presence of the alkaline electrolytes required for their redox-based energy storage. A layered Co(OH)2–organic hybrid material that forms a hierarchical structure consisting of micrometer-long, 30 nm diameter tubes with concentric curved layers of Co(OH)2 and 1-pyrenebutyric acid is reported. The nanotubular structure offers high surface area as well as macroscopic orientation perpendicular to the substrate for efficient electron transfer. Using a comparison with flat films of the same composition, it is demonstrated that the superior performance of the nanotubular films is the result of a large accessible surface area for redox activity. It is found that the organic molecules used to template nanotubular growth also impart stability to the hybrid when present in the alkaline environments necessary for redox function.A layered Co(OH)2–organic hybrid material consisting of multiwalled nanotubes with preferred alignment is electrodeposited on conductive substrates for use as energy storage electrodes. The molecular structure of the organic component determines the morphology of the hybrid material and its resulting electrochemical performance. The same organic molecules used to template nanotubular growth enhance the hybrid material's stability when present in alkaline electrolytes.
      PubDate: 2017-11-20T07:52:01.268921-05:
      DOI: 10.1002/adfm.201702320
       
  • A Multifunctional Polymeric Periodontal Membrane with Osteogenic and
           Antibacterial Characteristics
    • Authors: Amir Nasajpour; Sahar Ansari, Chiara Rinoldi, Afsaneh Shahrokhi Rad, Tara Aghaloo, Su Ryon Shin, Yogendra Kumar Mishra, Rainer Adelung, Wojciech Swieszkowski, Nasim Annabi, Ali Khademhosseini, Alireza Moshaverinia, Ali Tamayol
      Abstract: Periodontitis is a prevalent chronic, destructive inflammatory disease affecting tooth-supporting tissues in humans. Guided tissue regeneration strategies are widely utilized for periodontal tissue regeneration generally by using a periodontal membrane. The main role of these membranes is to establish a mechanical barrier that prevents the apical migration of the gingival epithelium and hence allowing the growth of periodontal ligament and bone tissue to selectively repopulate the root surface. Currently available membranes have limited bioactivity and regeneration potential. To address such challenges, an osteoconductive, antibacterial, and flexible poly(caprolactone) (PCL) composite membrane containing zinc oxide (ZnO) nanoparticles is developed. The membranes are fabricated through electrospinning of PCL and ZnO particles. The physical properties, mechanical characteristics, and in vitro degradation of the engineered membrane are studied in detail. Also, the osteoconductivity and antibacterial properties of the developed membrane are analyzed in vitro. Moreover, the functionality of the membrane is evaluated with a rat periodontal defect model. The results confirmed that the engineered membrane exerts both osteoconductive and antibacterial properties, demonstrating its great potential for periodontal tissue engineering.An osteoconductive, antibacterial, and flexible poly(caprolactone) composite membrane containing zinc oxide (ZnO) nanoparticles is developed through electrospinning for periodontal tissue engineering. The osteoconductivity and antibacterial properties of the developed membrane are analyzed in vitro. Moreover, the functionality of the membrane is evaluated with a rat periodontal defect model.
      PubDate: 2017-11-10T02:00:02.805138-05:
      DOI: 10.1002/adfm.201703437
       
  • PtCoFe Nanowire Cathodes Boost Short-Circuit Currents of Ru(II)-Based
           Dye-Sensitized Solar Cells to a Power Conversion Efficiency of 12.29%
    • Authors: Chin-Cheng (Paul) Chiang; Chang-Yu Hung, Shang-Wei Chou, Jing-Jong Shyue, Kum-Yi Cheng, Pei-Jen Chang, Ya-Yun Yang, Ching-Yen Lin, Ting-Kuang Chang, Yun Chi, Hung-Lung Chou, Pi-Tai Chou
      Abstract: PtCoFe nanowires with different alloying compositions are chemically prepared and acted as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) with Ru(II)-based dyes. Due to their superior I3− reduction activity, PtCoFe nanowires with rich (111) facets enhance the performance of DSSCs. Hence, N719 DSSCs with PtCoFe nanowires, respectively, produce better power conversion efficiency (PCE) of 8.10% for Pt33Co24Fe43 nanowire, 8.33% for Pt74Co12Fe14 nanowire, and 9.26% for Pt49Co23Fe28 nanowire in comparison to the PCE of Pt CE (7.32%). Further, the PRT-22 DSSC with Pt49Co23Fe28 nanowire exhibits a maximum PCE of 12.29% with a certificated value of 12.0%, which surpass the previous PCE record of the DSSCs with Ru(II)-based dyes. The photovoltaic and electrochemical results reveal the composition-dependent activity along with a volcano-shaped trend in the I−/I3− redox reaction. Theoretical work on the adsorption energies of I2, the desorption energies of I−, and the corresponding absolute energy demonstrates that the I3− reduction activity followed in the order of Pt49Co23Fe28(111) plane> Pt74Co12Fe14(111) plane> Pt33Co24Fe43(111) plane, proving Pt49Co23Fe28 nanowire to be a superior cathode material for DSSCs.PtCoFe nanowires with rich (111) planes are chemically prepared and act as the counter electrodes of dye-sensitized solar cells (DSSCs). Evidently, Pt49Co23Fe28 nanowires demonstrate the superior catalytic properties with respect to the I−/I3− redox reactions. Thus, PRT-22 DSSC based on Pt49Co23Fe28 nanowire produces an impressive power conversion efficiency of 12.29%.
      PubDate: 2017-11-02T03:01:33.373176-05:
      DOI: 10.1002/adfm.201703282
       
 
 
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