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  Subjects -> CHEMISTRY (Total: 850 journals)
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CHEMISTRY (600 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 32)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 22)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 222)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 20)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription  
Acta Chimica Slovaca     Open Access   (Followers: 1)
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: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 49)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
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: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 18)
Advances in Nanoparticles     Open Access   (Followers: 13)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
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)
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: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Full-text available via subscription   (Followers: 12)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 154)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 211)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 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: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 22)
Applied Surface Science     Hybrid Journal   (Followers: 26)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 9)
Biochemistry     Full-text available via subscription   (Followers: 280)
Biochemistry Insights     Open Access   (Followers: 5)
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: 18)
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: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 111)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 97)
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: 2)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 66)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 12)
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: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 172)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 15)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemical Week     Full-text available via subscription   (Followers: 7)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
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: 138)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 17)
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: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 192)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 8)
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: 23)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 11)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 4)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 53)
Dalton Transactions     Full-text available via subscription   (Followers: 19)
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: 3)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 8)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)

        1 2 3 | Last

Journal Cover Advanced Functional Materials
  [SJR: 5.21]   [H-I: 203]   [49 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  [1583 journals]
  • Deciphering the NH4PbI3 Intermediate Phase for Simultaneous Improvement on
           Nucleation and Crystal Growth of Perovskite
    • Authors: Haonan Si; Qingliang Liao, Zhuo Kang, Yang Ou, JingJing Meng, Yichong Liu, Zheng Zhang, Yue Zhang
      Abstract: The NH4PbI3-based phase transformation is realized by simply adding NH4I additive, in order to simultaneously control perovskite nucleation and crystal growth. Regarding the nucleation process, the NH4+ with small ionic radius preferentially diffuses into the [PbI6]4− octahedral layer to form NH4PbI3, which compensates the lack of CH3NH3I (MAI) precipitation. The generation of NH4PbI3 intermediate phase results in extra heterogeneous nucleation sites and reduces the defects derived from the absence of MA+. Regarding the crystal growth process, the cation exchange process between MA+ and NH4+, instead of the MAs directly entering, successfully retards the crystal growth. Such NH4PbI3 consumption process slows down the crystal growth, which effectively improves the perovskite quality with lowered defect density. The cooperation of these two effects eventually leads to the high-quality perovskite with enlarged grain size, prolonged photoluminescence lifetime, lowered defect density, and increased carrier concentration, as well as the finally enhanced photovoltaic performance. Moreover, NH3 as a byproduct further facilitates the proposed transformation process and no external residue remains even without any post-treatment. Such methodology of introducing a novel phase transformation to simultaneously control nucleation and crystal growth processes is of universal significance for further devotion in the foreseeable perovskite solar cells (PSCs) evolution.An innovative NH4I-induced phase transformation is designed to optimize the perovskite crystallization from both nucleation and crystal growth aspects. The rational designed intermediate phase NH4PbI3 simultaneously contributes to the extra heterogeneous nucleation sites and slows down crystal growth rate, which finally leads to the optimized perovskite quality and advanced photovoltaic performance with extra 10% improvement.
      PubDate: 2017-06-22T01:51:46.609042-05:
      DOI: 10.1002/adfm.201701804
       
  • Imaging: Multifunctional Biomedical Imaging in Physiological and
           
    • Authors: Kangquan Shou; Chunrong Qu, Yao Sun, Hao Chen, Si Chen, Lei Zhang, Haibo Xu, Xuechuan Hong, Aixi Yu, Zhen Cheng
      Abstract: In article number 1700995, Aixi Yu, Zhen Cheng, and co-workers describe the creation of highly biocompatible, small-organic-molecules-based nano-vesicles with fluorescent emission in the NIR-II window. This imaging agent can noninvasively and dynamically visualize many physiological and pathological conditions, and aid surgeons in performing accurate surgery. This approach will enable better diseases diagnosis and treatment in the era of precision medicine.
      PubDate: 2017-06-16T08:40:24.960749-05:
      DOI: 10.1002/adfm.201770144
       
  • Fluorescence Imaging: Organic Nanoprobe Cocktails for Multilocal and
           Multicolor Fluorescence Imaging of Reactive Oxygen Species (Adv. Funct.
           Mater. 23/2017)
    • Authors: Chao Yin; Houjuan Zhu, Chen Xie, Lei Zhang, Peng Chen, Quli Fan, Wei Huang, Kanyi Pu
      Abstract: Quli Fan, Kanyi Pu, and co-workers report a cocktail approach to develop nanoparticle probes for simultaneous and differential multicolor imaging of reactive oxygen species in multi-organelles in living cells. This work, described in article number 1700493, offers a convenient method to trace biomarkers in multiple subcellular environments.
      PubDate: 2017-06-16T08:40:24.905912-05:
      DOI: 10.1002/adfm.201770141
       
  • Masthead: (Adv. Funct. Mater. 23/2017)
    • PubDate: 2017-06-16T08:40:24.827254-05:
      DOI: 10.1002/adfm.201770142
       
  • Thin Films: Solution-Processed Nanoporous Organic Semiconductor Thin
           Films: Toward Health and Environmental Monitoring of Volatile Markers
           (Adv. Funct. Mater. 23/2017)
    • Authors: Fengjiao Zhang; Ge Qu, Erfan Mohammadi, Jianguo Mei, Ying Diao
      Abstract: A generic method to solution-process nanoporous electronic thin films is demonstrated by Ying Diao and co-workers in article number 1701117. The fabricated nanoporous electronic devices exhibit highly sensitive detection of volatile organic compounds below 1 ppb and could potentially be applied for personalized health and environmental monitoring.
      PubDate: 2017-06-16T08:40:23.73224-05:0
      DOI: 10.1002/adfm.201770145
       
  • Contents: (Adv. Funct. Mater. 23/2017)
    • PubDate: 2017-06-16T08:40:22.799972-05:
      DOI: 10.1002/adfm.201770143
       
  • Optoelectronic Devices: Solution-Growth Strategy for Large-Scale “CuGaO2
           Nanoplate/ZnS Microsphere” Heterostructure Arrays with Enhanced UV
           Adsorption and Optoelectronic Properties (Adv. Funct. Mater. 23/2017)
    • Authors: Yanmei Li; Yun Song, Yingchang Jiang, Mingxiang Hu, Zhichang Pan, Xiaojie Xu, Hongyu Chen, Yuesheng Li, Linfeng Hu, Xiaosheng Fang
      Abstract: In article number 1701066, Linfeng Hu, Xiaosheng Fang, and co-workers rationally design large-scaled CuGaO2 nanoplate/ZnS microsphere p-n arrays through a facile low-temperature solution strategy associated with an oil-water interfacial self-assembly approach. The ZnS microspheres are grown on the CuGaO2 thin-film through an Ostwald ripening mechanism, and the as-designed CuGaO2 nanoplate/ZnS microsphere heterostructure arrays exhibit drastically enhanced optoelectronic properties in UV-light sensitivity.
      PubDate: 2017-06-16T08:40:21.887225-05:
      DOI: 10.1002/adfm.201770140
       
  • Micrometer-Sized RuO2 Catalysts Contributing to Formation of Amorphous
           Na-Deficient Sodium Peroxide in Na–O2 Batteries
    • Authors: Feng Wu; Yi Xing, Jingning Lai, Xiaoxiao Zhang, Yusheng Ye, Ji Qian, Li Li, Renjie Chen
      Abstract: The results obtained herein demonstrate that the oxygen electrode plays a critical role in determining the morphology and chemical composition of discharge products in Na–O2 batteries. Micrometer-sized cubic NaO2, film-like NaO2, and nano-sized amorphous spherical Na2-xO2 are characterized as the main discharge products on the surface of reduced graphite oxide (rGO), boron-doped rGO (B-rGO), and micrometer-sized RuO2 catalyst-coated B-rGO (m-RuO2-B-rGO) cathodes, respectively. The Na–O2 battery with m-RuO2-B-rGO as the cathode exhibits a much longer cycle life than those with the other cathodes, maintaining an unchanged capacity (0.5 mAh cm-2) after 100 cycles at a current density of 0.05 mA cm-2. A good rate capability and deep discharge–charge energy efficiency are also obtained. The excellent electrochemical performance of the battery is attributed to the effect of the micrometer-sized RuO2 catalyst. Owing to the high affinity of RuO2 for oxygen, the amorphous phase Na2-xO2 discharge product, which has good electrical contact with the RuO2 particles, can decompose completely under 3.1 V without a sudden voltage jump. Meanwhile, the micrometer-sized RuO2 catalysts also provide enough active sites and space for the reactions, and effectively minimize the occurrence of side reactions between discharge products and carbon defects.The oxygen electrode determines the morphology and composition of the discharge product in the Na–O2 battery, which simultaneously influences the cycling performance. Attributing to the effect of micrometer-sized RuO2 catalyst, the Na2-xO2 with amorphous phase is identified as discharge products, and the occurrence of the side reactions is effectively minimized. Notably, the Na–O2 battery with m-RuO2-B-rGO as cathode achieves a long cycle life.
      PubDate: 2017-06-16T01:31:56.595302-05:
      DOI: 10.1002/adfm.201700632
       
  • Chemically Functionalized Natural Cellulose Materials for Effective
           Triboelectric Nanogenerator Development
    • Authors: Chunhua Yao; Xin Yin, Yanhao Yu, Zhiyong Cai, Xudong Wang
      Abstract: Cellulose, the most abundant natural polymer, is renewable, biodegradable, and cost competitive. This paper reports the development of a high-performance triboelectric nanogenerator (TENG) with both contacting materials made from cellulosic materials. Cellulose nanofibrils (CNFs) are used as the raw material, and chemical reaction approaches are employed to attach nitro groups and methyl groups to cellulose molecules to change the tribopolarities of CNF, which in turn significantly enhances the triboelectric output. Specifically, the nitro-CNF possesses a negative surface charge density of 85.8 µC m−2, while the methyl-CNF possesses a positive surface charge density of 62.5 µC m−2, reaching 71% and 52% of that for fluorinated ethylene propylene (FEP), respectively. The figure of merit of the nitro-CNF and methyl-CNF is quantified to be 0.504 and 0.267, respectively, comparable to or exceeding a number of common synthetic polymers, such as Kapton, polyvinylidene fluoride, and polyethylene. The TENG fabricated from nitro-CNF paired with methyl-CNF demonstrates an average voltage output of 8 V and current output of 9 µA, which approaches the same level obtained from TENG made from FEP. This work demonstrates a successful strategy of using environmentally friendly, abundant cellulosic materials for replacing the synthetic polymers in TENG development.Cellulose nanofibrils (CNFs) are chemically functionalized with nitro groups and methyl groups to engineer their tribopolarities, which in turn significantly enhances the electrical output of the triboelectric nanogenerator. The figures of merit of the nitro-CNF and methyl-CNF are quantified to be 0.51 and 0.28, respectively, comparable to or exceeding a number of common synthetic triboelectric polymer materials.
      PubDate: 2017-06-16T01:31:49.295688-05:
      DOI: 10.1002/adfm.201700794
       
  • High-Yield Synthesis of Multifunctional Tellurium Nanorods to Achieve
           Simultaneous Chemo-Photothermal Combination Cancer Therapy
    • Authors: Wei Huang; Yanyu Huang, Yuanyuan You, Tianqi Nie, Tianfeng Chen
      Abstract: Tellurium (Te) is an important semiconductor material with low band-gap energy, which has attracted considerable attention in recent years, due to its special chemical and physical properties and wide potential in electrochemistry, optoelectronics, and biological fields. This study demonstrates a facile and high-yield synthesis strategy of Te nanorods (PTW-TeNRs) decorated by polysaccharide–protein complex, which can achieve simultaneous chemo-photothermal combination therapy against cancers. PTW-TeNRs alone possess high stability under physiological conditions, potent anticancer activities through induction of reactive oxygen species overproduction, and high selectivity among tumor and normal cells. More importantly, they exhibit strong near-infrared (NIR) absorbance and good photothermal conversion ability from NIR light to heat energy. Furthermore, in combination with NIR laser irradiation, PTW-TeNRs exhibit excellent chemo-photothermal efficiency and low toxicity as evidenced by highly efficient tumor ablation ability, but show no obvious histological damage to the major organs. Taken together, this study provides a valid tactic for facile synthesis of multifunctional tellurium nanorods for efficient and combinational cancer therapy.A facile and high-yield synthesis of multifunctional tellurium nanorods enables simultaneous chemo-photo-thermal combination cancer therapy.
      PubDate: 2017-06-16T01:31:45.659551-05:
      DOI: 10.1002/adfm.201701388
       
  • Activated Surface Charge-Reversal Manganese Oxide Nanocubes with High
           Surface-to-Volume Ratio for Accurate Magnetic Resonance Tumor Imaging
    • Authors: Ming Lei; Chen Fu, Xiao Cheng, Bin Fu, Niuniu Wu, Qiang Zhang, Ailing Fu, Jingliang Cheng, Jinhao Gao, Zhenghuan Zhao
      Abstract: Investigating the surface structure, including crystal surface and surface-coating ligands, of nanoparticulate T1 contrast agent may help to understand the T1 relaxation enhancement in vitro and in vivo. This study presents a novel strategy to develop high-performance T1 magnetic resonance imaging (MRI) contrast agents through optimizing the nanocrystal surface and the nanobio interface. Based on the optimized crystal surface, the novel manganese oxide nanocubes (MOCs) show significantly higher surface-to-volume ratio and an approximately threefold higher r1 value compared to traditional manganese oxide nanospheres. Concurrently, transferring MOCs into aqueous media by dopamine derivatization can avoid the oxidation of Mn(II) ions and provide abundant magnetic core. This optimized surface endows MOCs with a high chemical exchange efficiency during T1 relaxation. Of particular significance, a rationally designed pH-induced charge-switchable surfaces can be negatively charged and corona-free in blood and positively charged surface in tumor sites. This unique feature improves the circulation behavior of this intelligent T1 contrast agent in blood and increases cancer cell uptake to achieve accurate detection of solid tumor, holding great potential in aiding early and precise tumor diagnosis. This study provides a novel tool for sophisticated design of high-performance T1 MRI contrast agents in bioimaging applications.Surfaces of biomedical nanomaterials can be mainly divided into two aspects, those are crystal surface and nanobio interface. Chemical exchange between surface of T1 contrast agents (CAs) and protons is the key factor to shorten longitudinal relaxation of protons. Thus, one can develop superior T1 CAs by engineering the crystal surface and nanobio interface to access accurate diagnosis.
      PubDate: 2017-06-16T01:31:27.914107-05:
      DOI: 10.1002/adfm.201700978
       
  • Functional Carbon Nanomesh Clusters
    • Authors: Changxia Li; Zengling Li, Zhihua Cheng, Xiaoteng Ding, Jing Zhang, Rudan Huang, Liangti Qu
      Abstract: A new type of atom-thin carbon nanomesh clusters (CMCs) is prepared through a self-sacrificial and morphology-reserved thermal transformation of electrodeposited zinc coordination polymer (Zn-CP). Such a unique structure can effectively inhibit the sheet stacking due to the self-formed cluster morphology of Zn-CP. The clusters are composed of nitrogen-doped, continuous, interconnected, one-/two-atom-thick carbon nanosheets, which not only effectively inhibit the sheet stacking but also significantly benefit ion transport. As a result, as active electrode material of supercapacitor in aqueous electrolytes, the resultant nitrogen-doped CMC (N-CMC) yields a capacitance of up to 984 F g−1 at 0.5 A g−1 and excellent cycling stability with 137% of its initial capacitance after 40 000 cycles, both higher than most of reported graphene-based and carbon-based electrode materials. On the other hand, the final N-doped CMC also exhibits superior electrocatalytic activities for oxygen reduction reaction.Carbon nanomesh clusters have been prepared by a catalyst-free, self-sacrificial template strategy. The unique architecture with high specific surface area and hierarchically arranged pores exhibits excellent electrocapacitive performance and superior electrocatalytic activities for oxygen reduction reaction.
      PubDate: 2017-06-16T01:31:13.479294-05:
      DOI: 10.1002/adfm.201701514
       
  • MO-Co@N-Doped Carbon (M = Zn or Co): Vital Roles of Inactive Zn and Highly
           Efficient Activity toward Oxygen Reduction/Evolution Reactions for
           Rechargeable Zn–Air Battery
    • Authors: Biaohua Chen; Xiaobo He, Fengxiang Yin, Hao Wang, Di-Jia Liu, Ruixing Shi, Jinnan Chen, Hongwei Yin
      Abstract: A highly efficient bifunctional oxygen catalyst is required for practical applications of fuel cells and metal–air batteries, as oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are their core electrode reactions. Here, the MO-Co@N-doped carbon (NC, M = Zn or Co) is developed as a highly active ORR/OER bifunctional catalyst via pyrolysis of a bimetal metal–organic framework containing Zn and Co, i.e., precursor (CoZn). The vital roles of inactive Zn in developing highly active bifunctional oxygen catalysts are unraveled. When the precursors include Zn, the surface contents of pyridinic N for ORR and the surface contents of Co–Nx and Co3+/Co2+ ratios for OER are enhanced, while the high specific surface areas, high porosity, and high electrochemical active surface areas are also achieved. Furthermore, the synergistic effects between Zn-based and Co-based species can promote the well growth of multiwalled carbon nanotubes (MWCNTs) at high pyrolysis temperatures (≥700 °C), which is favorable for charge transfer. The optimized CoZn-NC-700 shows the highly bifunctional ORR/OER activity and the excellent durability during the ORR/OER processes, even better than 20 wt% Pt/C (for ORR) and IrO2 (for OER). CoZn-NC-700 also exhibits the prominent Zn–air battery performance and even outperforms the mixture of 20 wt% Pt/C and IrO2.MO-Co@N-doped carbon (M = Zn or Co) are prepared by using a bimetal metal–organic framework (containing Zn and Co) as precursor, showing excellent activity (EORR − EOER ≈ 0.78 V) and durability toward both oxygen reduction and evolution reactions as well as prominent Zn–air battery performance. It is revealed that inactive Zn plays vital roles in developing these highly efficient bifunctional catalysts.
      PubDate: 2017-06-14T06:10:32.564492-05:
      DOI: 10.1002/adfm.201700795
       
  • White Organic LED with a Luminous Efficacy Exceeding 100 lm W−1 without
           Light Out-Coupling Enhancement Techniques
    • Authors: Sheng-Fan Wu; Si-Hua Li, Ya-Kun Wang, Chen-Chao Huang, Qi Sun, Jiao-Jiao Liang, Liang-Sheng Liao, Man-Keung Fung
      Abstract: Luminous efficacy (LE), which is given by the ratio of luminous flux to power, is commonly used to measure the power consumption of a light source. Unfortunately, the LE of white organic light-emitting diodes (OLEDs) still lags behind those of inorganic LED for practically used (>100 lm W−1). In this paper, an ultraefficient white OLED is discussed based on a newly designed thermally activated delayed fluorescent exciplex host. The resulting white OLED delivers an unusually high forward-viewing LE of 105.0 lm W−1 and external quantum efficiency (EQE) ηext of ≈30% (without using any optical out-coupling techniques). As far as it is known, specifically, these efficiencies are the highest values among the published white OLEDs to date. Two-color warm white emission is realized with Commission International de I'Eclairage coordinates of (0.40, 0.48) at a brightness of 1000 cd m−2. Furthermore, the well-matched energy alignment endows the device with an extremely low turn-on voltage (≈2.5 V). Such high efficiencies and excellent device performance should benefit from the advantages of exciplex material solely used as the host. Therefore, this study anticipates that the findings have great potential to boost the LE of OLEDs, and more importantly, fulfill the power efficacy requirement for lighting applications.An outstanding blue exciplex, named mCP:B4PyMPM, is implemented as a host for white organic light-emitting diode (OLED). Super-high luminous efficacy of 105.0 lm W−1 and external quantum efficiency of>28% are realized without employing optical out-coupling techniques. Efficiency roll-off of mCP:B4PyMPM based OLEDs is relatively mild. Additionally, extremely low turn-on voltages (≈2.5 V) and warm white emission are also achieved.
      PubDate: 2017-06-14T01:41:04.455596-05:
      DOI: 10.1002/adfm.201701314
       
  • Autonomous Integrated Microfluidic Circuits for Chip-Level Flow Control
           Utilizing Chemofluidic Transistors
    • Authors: Philipp Frank; David Gräfe, Christopher Probst, Sebastian Haefner, Martin Elstner, Dietmar Appelhans, Dietrich Kohlheyer, Brigitte Voit, Andreas Richter
      Abstract: In microfluidics, a variety of platforms have emerged facilitating various physical effects for manipulating small volumes. Despite great functional diversity, most technologies are incapable of acting on direct feedback from the process liquid and instead require a sophisticated external control unit off-chip. Here, a microfluidic platform concept is demonstrated utilizing the volume phase transition of polymers via transistor-like components to actively switch between discrete fluid streams. Control is integrated at chip level for the first time, relying on information carried within the process liquid. Control commands are chemical signals such as solvent concentration, pH-value, or even salt. The developed logical modules can be interconnected independently through conclusive signal propagation, supporting an integrated circuit concept and large-scale integration. The approach enables the development of the basic logic gates (AND, OR, NOT) and their negated counterparts, as well as more sophisticated circuits such as an RS flip-flop and a chemofluidic oscillator.Microfluidic integrated circuits (ICs) based on stimuli-responsive hydrogels utilize chemical information in form of molecule concentration for flow control. The circuit concept in combination with a chemofluidic transistor-like device facilitates a vivid analogy to electronics. The implementation of a series of basic circuits such as logic gates, an RS flip-flop, an oscillator circuit, and a first application in single-cell analysis are demonstrated.
      PubDate: 2017-06-14T01:40:56.511887-05:
      DOI: 10.1002/adfm.201700430
       
  • Tough Elastomers with Superior Self-Recoverability Induced by Bioinspired
           Multiphase Design
    • Authors: Shoma Yoshida; Hirotaka Ejima, Naoko Yoshie
      Abstract: Incorporating reversible sacrificial bonds in network polymers not only toughens these materials but also endows them with self-recoverability. However, self-recoverability is only realized for dispersed energy less than 10 MJ m−3. It remains a challenge to achieve simultaneous high stretchability, toughness, and recoverability. Here, inspired by the structure of mussel byssus cuticles, a new design strategy is proposed and demonstrated to improve both the toughness and self-recoverability of elastomers by introducing a microphase-separated structure with different physical crosslink densities. This structure can be achieved using a carefully designed comonomer sequence distribution of hydrogen bonding units in an ABA-type triblock copolymer. The A blocks form hard domains with dense crosslinking that prevents macroscopic deformation, while the B blocks form a softer matrix with sparse and dynamic crosslinks that serve as sacrificial bonds. This elastomer exhibits high toughness (≈62 MJ m−3), self-healing, and most notably, excellent self-recovery (recovery against 650% elongation and 17 MPa tensile stress with a dissipated energy>27 MJ m−3 at room temperature). This combination of toughness, self-healing, and self-recovery expands the range of applications of these advanced dynamic materials.Polymers with toughness and excellent self-recoverability are achieved by a bioinspired microphase-separated structure with different physical crosslink densities. This structure is realized by a carefully designed comonomer sequence distribution of an ABA type triblock copolymer where the A and B blocks contain high and low amount of quadruple hydrogen-bonding 2-ureido-4[1H]-pyrimidinone groups, respectively.
      PubDate: 2017-06-14T01:40:25.807114-05:
      DOI: 10.1002/adfm.201701670
       
  • Zn Single Atom Catalyst for Highly Efficient Oxygen Reduction Reaction
    • Authors: Ping Song; Mi Luo, Xiaozhi Liu, Wei Xing, Weilin Xu, Zheng Jiang, Lin Gu
      Abstract: The authors report first a new type of nitrogen-triggered Zn single atom catalyst, demonstrating high catalytic activity and remarkable durability for the oxygen reduction reaction process. Both X-ray absorption fine structure spectra and theoretical calculations suggest that the atomically dispersed Zn-N4 site is the main, as well as the most active, component with O adsorption as the rate-limiting step at a low overpotential of 1.70 V. This work opens a new field for the exploration of high-performance Pt-free electrochemical oxygen reduction catalysts for fuel cells.The new nitrogen-triggered Zn single-atom catalyst shows high catalytic activity for the oxygen reduction reaction (ORR) process. The characterization and theoretical calculations suggest that the main active site is the dispersed Zn-N4 moiety, with O adsorption as the rate-limiting step at a low overpotential of 1.70 V. The single-atom ZnNx/C catalyst is one of the most promising Pt alternatives for the ORR process.
      PubDate: 2017-06-13T09:10:29.756182-05:
      DOI: 10.1002/adfm.201700802
       
  • Three-dimensional Printing for Catalytic Applications: Current Status and
           Perspectives
    • Authors: Xintong Zhou; Chang-jun Liu
      Abstract: Three-dimensional (3D) printing, also known as additive manufacturing, is a fabrication method that has recently received worldwide attention. It provides a convenient and economical way to prepare 3D structures in designable ways. As the technology has developed and the operational costs have decreased, the applications of 3D printing have greatly expanded. Catalyst fabrication is a promising area for 3D printing. Printing processes result in better control of catalyst structures and catalyst distribution. In this perspective, a general overview of the commonly available 3D printing methods that are feasible for the preparation of heterogeneous catalysts is given. Additionally, recent works on printing strategies and new materials for catalysts are discussed. Future development is also addressed.Three-dimensional (3D) printing is a fabrication method that has received worldwide attention. Recently, 3D printing has been applied to catalyst fabrication. In this perspective, a general overview of the commonly available 3D printing methods that are feasible for the preparation of heterogeneous catalysts is given. Recent works on printing strategies and new materials for catalysts are discussed. Future development is also addressed.
      PubDate: 2017-06-12T09:11:15.694671-05:
      DOI: 10.1002/adfm.201701134
       
  • Thermodynamic Aspects of Molluscan Shell Ultrastructural Morphogenesis
    • Authors: Igor Zlotnikov; Vanessa Schoeppler
      Abstract: Over the years, molluscan shells have become an exemplar model system to study the process of mineral formation by living organisms, the process of biomineralization. Typically, the shells consist of a number of mineralized ultrastructural motifs, each exhibiting a specific mineral-organic composite architecture. These are made of calcium carbonate building blocks having a well-defined three-dimensional morphology that is significantly different from the shape of inorganically formed counterparts. Shell ultrastructures are known to form via a biologically controlled extracellular mineralization pathway in which the organism has no direct control over mineral formation. The cellular tissue, responsible for shell biomineralization, forms an organic framework and sets-up the physical conditions necessary for the deposition of a specific morphology, whereas the growth of the mineral part of the shell proceeds spontaneously via the process of self-assembly. In this feature article, the ability to employ thermodynamic models from classical materials science to describe the process of self-assembly and structural evolution of a variety of shell architectures is reviewed. Having the potential to offer an analytical framework to express ultrastructure formation in time and in space, these models not only provide a deeper insight into shell biomineralization, but also suggest tools for novel composite materials design.Morphogenesis of molluscan shell ultrastructures is described in the scope of well-established thermodynamic and kinetic models from the fields of grain growth, coarsening and pattern formation. The focus is on spontaneous growth of the prismatic and the nacreous structures in bivalves.
      PubDate: 2017-06-12T09:10:40.923752-05:
      DOI: 10.1002/adfm.201700506
       
  • Neuro-Nano Interfaces: Utilizing Nano-Coatings and Nanoparticles to Enable
           Next-Generation Electrophysiological Recording, Neural Stimulation, and
           Biochemical Modulation
    • Authors: Ashlyn T. Young; Neil Cornwell, Michael A. Daniele
      Abstract: Neural interfaces provide a window into the workings of the nervous system—enabling both biosignal recording and modulation. Traditionally, neural interfaces have been restricted to implanted electrodes to record or modulate electrical activity of the nervous system. Although these electrode systems are both mechanically and operationally robust, they have limited utility due to the resultant macroscale damage from invasive implantation. For this reason, novel nanomaterials are being investigated to enable new strategies to chronically interact with the nervous system at both the cellular and network level. In this feature article, the use of nanomaterials to improve current electrophysiological interfaces, as well as enable new nano-interfaces to modulate neural activity via alternative mechanisms, such as remote transduction of electromagnetic fields are explored. Specifically, this article will review the current use of nanoparticle coatings to enhance electrode function, then an analysis of the cutting-edge, targeted nanoparticle technologies being utilized to interface with both the electrophysiological and biochemical behavior of the nervous system will be provided. Furthermore, an emerging, specialized-use case for neural interfaces will be presented: the modulation of the blood-brain barrier.Nanoparticles are emerging as platforms to both improve conventional neural interfaces and enable new strategies for remotely interfacing with the central and peripheral nervous system.
      PubDate: 2017-06-07T13:56:15.129696-05:
      DOI: 10.1002/adfm.201700239
       
  • Plant-Based Hollow Microcapsules for Oral Delivery Applications: Toward
           Optimized Loading and Controlled Release
    • Authors: Michael G. Potroz; Raghavendra C. Mundargi, Jurriaan J. Gillissen, Ee-Lin Tan, Sigalit Meker, Jae H. Park, Haram Jung, Soohyun Park, Daeho Cho, Sa-Ik Bang, Nam-Joon Cho
      Abstract: Efficient oral administration of protein-based therapeutics faces significant challenges due to degradation from the highly acidic conditions present in the stomach and proteases present in the digestive tract. Herein, investigations into spike-covered sunflower sporopollenin exine capsules (SECs) for oral protein delivery using bovine serum albumin (BSA) as a model drug are reported and provide significant insights into the optimization of SEC extraction, SEC loading, and controlled release. The phosphoric-acid-based SEC extraction process is optimized. Compound loading is shown to be driven by the evacuation of air bubbles from SEC cavities through the porous SEC shell wall, and vacuum loading is shown to be the optimal loading method. Three initial BSA-loading proportions are evaluated, leading to a practical loading efficiency of 22.3 ± 1.5 wt% and the determination that the theoretical maximum loading is 46.4 ± 2.5 wt%. Finally, an oral delivery formulation for targeted intestinal delivery is developed by tableting BSA-loaded SECs and enteric coating. BSA release is inhibited for 2 h in simulated gastric conditions followed by 100% release within 8 h in simulated intestinal conditions. Collectively, these results indicate that sunflower SECs provide a versatile platform for the oral delivery of therapeutics.Porous microcapsules extracted from sunflower pollen are used to develop an effective oral drug delivery system for targeted delivery of proteins to the intestinal tract. Sporopollenin exine capsule (SEC) extraction and loading are analyzed to provide insights into these processes and allow optimization. Tableting and enteric coating of SECs are shown to inhibit protein release in simulated gastric conditions and allow for full release in simulated intestinal conditions.
      PubDate: 2017-06-07T08:00:03.306152-05:
      DOI: 10.1002/adfm.201700270
       
  • Morphological Evolution and Magnetic Property of Rare-Earth-Doped Hematite
           Nanoparticles: Promising Contrast Agents for T1-Weighted Magnetic
           Resonance Imaging
    • Authors: Hao Wan; Pengfei Rong, Xiaohe Liu, Litong Yang, Yong Jiang, Ning Zhang, Renzhi Ma, Shuquan Liang, Haidong Wang, Guanzhou Qiu
      Abstract: A series of uniform rare-earth-doped hematite (α-Fe2O3) nanoparticles are synthesized by a facile hydrothermal strategy. In a typical case of gadolinium (Gd)-doped α-Fe2O3, the morphology and chemical composition can be readily tailored by tuning the initial proportion of Gd3+/Fe3+ sources. As a result, the products are observed to be stretched into more elongated shapes with an increasing dopant ratio. As a benefit of such an elongated morphological feature and Gd3+ ions of larger effective magnetic moment than Fe3+, the doped product with the highest ratio of Gd3+ at 5.7% shows abnormal ferromagnetic features with a remnant magnetization of 0.605 emu g−1 and a coercivity value of 430 Oe at 4 K. Density of states calculations also reveal the increase of total magnetic moment induced by Gd3+ dopant in α-Fe2O3 hosts, as well as possible change of magnetic arrangement. As-synthesized Gd-doped α-Fe2O3 nanoparticles are probed as contrast agents for T1-weighted magnetic resonance imaging, achieving a remarkable enhancement effect for both in vitro and in vivo tests.The morphology and chemical composition of rare-earth-doped hematite nanoparticles can be readily tailored, bringing about a ferromagnetic feature with the highest Gd3+ dopant ratio of 5.7%. As-synthesized Gd-doped hematite nanoparticles are revealed as promising contrast agents for T1-weighted magnetic resonance imaging, achieving a remarkable enhancement effect for both in vitro and in vivo tests.
      PubDate: 2017-06-07T01:55:34.243822-05:
      DOI: 10.1002/adfm.201606821
       
  • Elastomeric Fibrous Hybrid Scaffold Supports In Vitro and In Vivo Tissue
           Formation
    • Authors: Nafiseh Masoumi; Dane Copper, Peter Chen, Alexander Cubberley, Kai Guo, Ruei-Zeng Lin, Bayoumi Ahmed, David Martin, Elena Aikawa, Juan Melero-Martin, John Mayer
      Abstract: Biomimetic materials with biomechanical properties resembling those of native tissues while providing an environment for cell growth and tissue formation, are vital for tissue engineering (TE). Mechanical anisotropy is an important property of native cardiovascular tissues and directly influences tissue function. This study reports fabrication of anisotropic cell-seeded constructs while retaining control over the construct's architecture and distribution of cells. Newly synthesized poly-4-hydroxybutyrate (P4HB) is fabricated with a dry spinning technique to create anelastomeric fibrous scaffold that allows control of fiber diameter, porosity, and rate ofdegradation. To allow cell and tissue ingrowth, hybrid scaffolds with mesenchymalstem cells (MSCs) encapsulated in a photocrosslinkable hydrogel were developed. Culturing the cellularized scaffolds in a cyclic stretch/flexure bioreactor resulted in tissue formation and confirmed the scaffold's performance under mechanical stimulation. In vivo experiments showed that the hybrid scaffold is capable of withstanding physiological pressures when implanted as a patch in the pulmonary artery. Aligned tissue formation occurred on the scaffold luminal surface without macroscopic thrombus formation. This combination of a novel, anisotropic fibrous scaffold and a tunable native-like hydrogel for cellular encapsulation promoted formation of 3D tissue and provides a biologically functional composite scaffold for soft-tissue engineering applications.Hybrid scaffolds composed of synthetic and biologic materials offer the potential for optimizing both cell compatibility and biomechanical characteristics of scaffolds for cardiovascular tissue engineered structures. The effects of fiber alignment, hydrogel incorporation, cellularization, and in vitro mechanical signaling are evaluated on electrospun poly-4-hydroxybutyrate scaffolds.
      PubDate: 2017-06-05T13:16:42.122794-05:
      DOI: 10.1002/adfm.201606614
       
  • Band-Tail Recombination in Hybrid Lead Iodide Perovskite
    • Authors: Adam D. Wright; Rebecca L. Milot, Giles E. Eperon, Henry J. Snaith, Michael B. Johnston, Laura M. Herz
      Abstract: Traps limit the photovoltaic efficiency and affect the charge transport of optoelectronic devices based on hybrid lead halide perovskites. Understanding the nature and energy scale of these trap states is therefore crucial for the development and optimization of solar cell and laser technology based on these materials. Here, the low-temperature photoluminescence of formamidinium lead triiodide (HC(NH2)2PbI3) is investigated. A power-law time dependence in the emission intensity and an additional low-energy emission peak that exhibits an anomalous relative Stokes shift are observed. Using a rate-equation model and a Monte Carlo simulation, it is revealed that both phenomena arise from an exponential trap-density tail with characteristic energy scale of ≈3 meV. Charge-carrier recombination from sites deep within the tail is found to cause emission with energy downshifted by up to several tens of meV. Hence, such phenomena may in part be responsible for open-circuit voltage losses commonly observed in these materials. In this high-quality hybrid perovskite, trap states thus predominantly comprise a continuum of energetic levels (associated with disorder) rather than discrete trap energy levels (associated, e.g., with elemental vacancies). Hybrid perovskites may therefore be viewed as classic semiconductors whose band-structure picture is moderated by a modest degree of energetic disorder.Low-temperature measurements of the photoluminescence from HC(NH2)2PbI3 thin films are presented. The emission exhibits a power-law intensity decay with time after excitation, and an additional low-energy peak displaying an anomalous Stokes shift. These phenomena demonstrate that charge–carrier recombination in this perovskite is mediated by a band tail with characteristic energy 3 meV, determined from a rate-equation model and Monte Carlo simulation.
      PubDate: 2017-06-05T13:16:24.972398-05:
      DOI: 10.1002/adfm.201700860
       
  • Lead-Free Polycrystalline Ferroelectric Nanowires with Enhanced Curie
           Temperature
    • Authors: Anuja Datta; Pedro E. Sanchez-Jimenez, Rabih Al Rahal Al Orabi, Yonatan Calahorra, Canlin Ou, Suman-Lata Sahonta, Marco Fornari, Sohini Kar-Narayan
      Abstract: Ferroelectrics are important technological materials with wide-ranging applications in electronics, communication, health, and energy. While lead-based ferroelectrics have remained the predominant mainstay of industry for decades, environmentally friendly lead-free alternatives are limited due to relatively low Curie temperatures (TC) and/or high cost in many cases. Efforts have been made to enhance TC through strain engineering, often involving energy-intensive and expensive fabrication of thin epitaxial films on lattice-mismatched substrates. Here, a relatively simple and scalable sol–gel synthesis route to fabricate polycrystalline (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 nanowires within porous templates is presented, with an observed enhancement of TC up to ≈300 °C as compared to ≈90 °C in the bulk. By combining experiments and theoretical calculations, this effect is attributed to the volume reduction in the template-grown nanowires that modifies the balance between different structural instabilities. The results offer a cost-effective solution-based approach for strain-tuning in a promising lead-free ferroelectric system, thus widening their current applicability.Nanowires of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCT-0.5BZT) are grown using a template-aided sol–gel synthesis route. These are found to have enhanced ferroelectric Curie temperature (TC) of ≈300 °C as compared to ≈90 °C in the bulk. BCT-0.5BZT in the bulk has limited applicability due to its room-temperature TC. The studies thus offer a cost-effective solution, by achieving enhanced TC via strain-tuning in BCT-0.5BZT nanowires.
      PubDate: 2017-06-01T13:22:54.877457-05:
      DOI: 10.1002/adfm.201701169
       
  • Gas Selective Ultrathin Organic Covalent Networks Synthesized by iPECVD:
           Does the Central Metal Ion Matter'
    • Authors: Minghui Wang; Nicolas D. Boscher, Katja Heinze, Karen K. Gleason
      Abstract: The potential of porphyrin-derived metal organic covalent networks (OCN) thin films on light gas separations has been recently demonstrated. However, whether or not the central metal ion of the porphyrin plays a key role on separation performance has yet to be elucidated. Here, one metal-free and three metal-containing (zinc(II), manganese(III), and cobalt(II)) porphyrin-derived OCN thin films are successfully deposited on various substrates via an easily scalable initiated plasma-enhanced chemical vapor deposition approach. Among these four porphyrin-derived OCN thin films exhibiting superior light gas separation performances, three of them are synthesized for the first time. The gas permeation properties of these four OCN thin films suggest that the central metal ions neither significantly alter the packing structure of resulting OCN thin films, nor introduce facilitated transport phenomena favoring oxygen transmission. This observation is further validated by density functional theory calculations. Additional aging tests are also carried out to evaluate the physical aging behavior of the OCN thin films.Metal-free and metal-containing porphyrin-derived organic covalent networks (OCN) thin films are successfully deposited using a low power initiated plasma-enhanced chemical vapor deposition technique. The role of the central metal ions on the light gas separation performance is elucidated by comparing gas permeation properties of these OCN thin films. The observations are further confirmed by density functional theory calculations.
      PubDate: 2017-05-31T08:57:26.673724-05:
      DOI: 10.1002/adfm.201606652
       
  • Solution-Processed Monolayer Organic Crystals for High-Performance
           Field-Effect Transistors and Ultrasensitive Gas Sensors
    • Authors: Boyu Peng; Shuyun Huang, Zhiwen Zhou, Paddy Kwok Leung Chan
      Abstract: This work innovatively develops a dual solution-shearing method utilizing the semiconductor concentration region close to the solubility limit, which successfully generates large-area and high-performance semiconductor monolayer crystals on the millimeter scale. The monolayer crystals with poly(methyl methacrylate) encapsulation show the highest mobility of 10.4 cm2 V−1 s−1 among the mobility values in the reported solution-processed semiconductor monolayers. With similar mobility to multilayer crystals, light is shed on the charge accumulation mechanism in organic field-effect transistors (OFETs), where the first layer on interface bears the most carrier transport task, and the other above layers work as carrier suppliers and encapsulations to the first layer. The monolayer crystals show a very low dependency on channel directions with a small anisotropic ratio of 1.3. The positive mobility–temperature correlation reveals a thermally activated carrier transport mode in the monolayer crystals, which is different from the band-like transport mode in multilayer crystals. Furthermore, because of the direct exposure of highly conductive channels, the monolayer crystal based OFETs can sense ammonia concentrations as low as 10 ppb. The decent sensitivity indicates the monolayer crystals are potential candidates for sensor applications.An innovative dual solution-shearing method that leads to highly crystallized organic semiconductor monolayers with mobility up to 10 cm2 V−1 s−1 is presented. The monolayers show Coulomb impurity limited mobility and hopping transport. The directly exposed transport channel allows for superior gas sensor performance.
      PubDate: 2017-05-31T08:57:16.078835-05:
      DOI: 10.1002/adfm.201700999
       
  • Manipulating Bubbles in Aqueous Environment via a Lubricant-Infused
           Slippery Surface
    • Authors: Cunming Yu; Xuanbo Zhu, Kan Li, Moyuan Cao, Lei Jiang
      Abstract: Designing functional interfaces to control solid/fluid interactions has emerged as an indispensable strategy for developing advanced materials and optimizing current technologies. Surfaces exhibiting special wettability offer many paradigms for regulating fluid behavior in practical applications including oil–water separation and fog harvesting. Nevertheless, the flexible manipulation of air bubbles under water still has room for further exploration. Here, it is reported that the lubricant-infused slippery (LIS) surface with water repellency is applicable to manipulate bubbles in an aqueous environment. On the basis of the sufficient bubble adhesion, the shaped LIS tracks can be used in guiding the bubble delivery and facilitating continuous bubble distribution. Through the incorporation of an asymmetrical structure into the LIS surface, a triangle-shaped bubble holder is capable of controlling a single bubble with ease. Moreover, the LIS surface is integrated with a H2 microbubble evolving apparatus, demonstrating a potential method for in situ capture and delivery of microbubbles. The current finding reveals the meaningful interaction between underwater bubbles and the LIS surface, providing several examples for the applications of this bubble carrier, which should shed new light on the development of bubble-controlling interfaces.Smart manipulation of underwater bubbles depends on the functional interface with special wettability. The hydrophobic lubricant-infused slippery substrate is proven to have promising bubble capturing and delivering ability in an aqueous environment, which facilitates a series of continuous and controllable bubble manipulating processes.
      PubDate: 2017-05-31T08:57:08.584254-05:
      DOI: 10.1002/adfm.201701605
       
  • Oxygen-Deficient Bismuth Oxide/Graphene of Ultrahigh Capacitance as
           Advanced Flexible Anode for Asymmetric Supercapacitors
    • Authors: Rong Liu; Lina Ma, Gudan Niu, Xiaolong Li, Enyuan Li, Yang Bai, Guohui Yuan
      Abstract: Oxygen-deficient bismuth oxide (r-Bi2O3)/graphene (GN) is designed, fabricated, and demonstrated via a facile solvothermal and subsequent solution reduction method. The ultrafine network bacterial cellulose (BC) as substrate for r-Bi2O3/GN exhibits high flexibility, remarkable tensile strength (55.1 MPa), and large mass loading of 9.8 mg cm−2. The flexible r-Bi2O3/GN/BC anode delivers appreciable areal capacitance (6675 mF cm−2 at 1 mA cm−2) coupled with good rate capability (3750 mF cm−2 at 50 mA cm−2). In addition, oxygen vacancies have great influence on the capacitive performance of Bi2O3, delivering significantly improved capacitive values than the untreated Bi2O3 flexible electrode, and ultrahigh gravimetric capacitance of 1137 F g−1 (based on the mass of r-Bi2O3) can be obtained, achieving 83% of the theoretical value (1370 F g−1). Flexible asymmetric supercapacitor is fabricated with r-Bi2O3/GN/BC and Co3O4/GN/BC paper as the negative and positive electrodes, respectively. The operation voltage is expanded to 1.6 V, revealing a maximum areal energy density of 0.449 mWh cm−2 (7.74 mWh cm−3) and an areal power density of 40 mW cm−2 (690 mW cm−3). Therefore, this flexible anode with excellent electrochemical performance and high mechanical properties shows great potential in the field of flexible energy storage devices.Oxygen-deficient bismuth oxide (r-Bi2O3)/graphene (GN) is designed, fabricated, and demonstrated via a facile solvothermal and subsequent solution reduction method. The ultrafine network bacterial cellulose (BC) as a substrate for r-Bi2O3/GN exhibits high flexibility, remarkable tensile strength, and large mass loading. Therefore, this high-performance flexible r-Bi2O3/GN/BC anode shows great potential in the field of flexible energy storage devices.
      PubDate: 2017-05-31T08:56:59.474787-05:
      DOI: 10.1002/adfm.201701635
       
  • Dendrimers as Powerful Building Blocks in Central Nervous System Disease:
           Headed for Successful Nanomedicine
    • Authors: Victoria Leiro; Sofia Duque Santos, Cátia D. F. Lopes, Ana Paula Pêgo
      Abstract: Dendrimers have emerged as a powerful class of nanomaterials in the nanomedicine field due to their unique structural features: globular, well-defined, highly branched and controllable structure, nanosize-scale, low polydispersity, and the presence of several terminal groups that can be functionalized with different ligands simulating the multivalency present in different biological systems. Although in its infancy, the application of dendrimers as therapeutics or theranostic tools in central nervous system (CNS) disorders is already significant and has opened promising avenues in the treatment of many conditions where the inherent “smartness” of the dendritic structures is being explored to effectively target the CNS. Here we present an overview of the past and future challenges of the use of dendrimers to respond to one of the ultimate challenges in the (nano)medicine field: to attain CNS repair and regeneration.Here is presented an overview of the past, present, and future challenges of the exploration of the inherent “smartness” of dendrimers to effectively target the central nervous system (CNS) to respond to one of the ultimate challenges in the (nano)medicine field: to attain CNS repair and regeneration.
      PubDate: 2017-05-30T13:53:05.965352-05:
      DOI: 10.1002/adfm.201700313
       
  • Multifunctional Molecular Beacon Micelles for Intracellular mRNA Imaging
           and Synergistic Therapy in Multidrug-Resistant Cancer Cells
    • Authors: Ruili Zhang; Shi Gao, Zhongliang Wang, Da Han, Lin Liu, Qingjie Ma, Weihong Tan, Jie Tian, Xiaoyuan Chen
      Abstract: Multidrug resistance (MDR) resulting from overexpression of P-glycoprotein (Pgp) transporters increases the drug efflux and thereby limits the chemotherapeutic efficacy. It is desirable to administer both an MDR1 gene silencer and a chemotherapeutic agent in a sequential way to generate a synergistic therapeutic effect in multidrug-resistant cancer cells. Herein, an anti-MDR1 molecular beacon (MB)-based micelle (a-MBM) nanosystem is rationally designed. It is composed of a diacyllipid core densely packed with an MB corona. One of Pgp-transportable agents, doxorubicin (DOX), is encapsulated in the hydrophobic core of the micelle and in the stem sequence of MB. The a-MBM-DOX nanosystem shows an efficient self-delivery, enhanced enzymatic stability, excellent target selectivity, and high drug-loading capacity. With its relatively high enzymatic stability, a-MBM-DOX initially facilitates intracellular MDR1 mRNA imaging to distinguish multidrug-resistant and non-multidrug-resistant cells and subsequently downregulates the MDR1 gene expression owing to an antisense effect. After that, the MB corona is degraded, destroying the micellar nanostructure and releasing DOX, which result in a high accumulation of DOX in OVCAR8/ADR cells and a high chemotherapeutic efficacy because of successful restoration of drug sensitivity. This micelle approach has the potential for both visualizing MDR1 mRNA and overcoming MDR in a sequential and synergistic way.Molecular beacon-based micelle system (a-MBM) presents its capability to combat multidrug resistance (MDR) in a sequential and synergistic way. With enhanced enzymatic stability, excellent target selectivity, and high drug-loading capacity, a-MBMs allows for visualization of MDR1 mRNA and specifically inhibits MDR1 gene expression. It also results in a high chemotherapeutic efficacy because of successful restoration of drug sensitivity.
      PubDate: 2017-05-30T13:53:00.956429-05:
      DOI: 10.1002/adfm.201701027
       
  • Carbon-Nanotube-Templated, Sputter-Deposited, Flexible Superconducting NbN
           Nanowire Yarns
    • Authors: Jeong-Gyun Kim; Haeyong Kang, Yourack Lee, Jeongmin Park, Joonggyu Kim, Thuy Kieu Truong, Eun Sung Kim, Doo Hyun Yoon, Young Hee Lee, Dongseok Suh
      Abstract: Flexible superconducting yarns consisting of sputter-deposited NbN nanowires on highly aligned carbon nanotube (CNT) array sheets are reported. In the microscopic view, the NbN nanowires are formed on top of individual CNT fibrils, and the superconductivity property of the twist-spun NbN–CNT yarn system is comparable to that of a typical NbN thin film on a normal solid substrate. Because of its intrinsic porosity, the system exhibits superior mechanical flexibility with a small bending radius. It also remains a superconducting state even when subjected to severe mechanical deformations, primarily due to the proximity superconductivity through carbon nanotube bundles. The results demonstrate the possibility of fabricating flexible superconducting yarns in a conventional thin-film deposition process, using ultraflexible free-standing CNT sheets as a template. In addition, preliminary tests on reducing the normal-state resistance toward superconducting cable applications are presented.A flexible superconducting yarn is presented consisting of NbN nanowires deposited on aligned carbon nanotube arrays and twisted. The system retains superconductivity even under severe mechanical deformation. A small bending radius and reduction in normal-state resistance are demonstrated toward possible applications to superconducting cables.
      PubDate: 2017-05-30T13:52:54.659284-05:
      DOI: 10.1002/adfm.201701108
       
  • Tunable Mechanoresponsive Self-Assembly of an Amide-Linked Dyad with Dual
           Sensitivity of Photochromism and Mechanochromism
    • Authors: Shenzhong Mo; Qingting Meng, Shulin Wan, Zhiqiang Su, Hong Yan, Ben Zhong Tang, Meizhen Yin
      Abstract: Photo- and mechanoluminescent materials that exhibit tunable emission properties when subjected to external stimuli have a wide variety of applications. However, most mechanoresponsive materials have a mechano-induced structural transition from crystalline to amorphous phase, and there are only few reports on the crystalline to crystalline transformation. This study reports an amide-linked dyad P1 containing spiropyran and naphthalimide chromophores with dual sensitivity of photochromism and mechanochromism. Under light and mechanical stimuli, P1 performs different color transition. With mechanical force, the morphologies of P1 change from microfiber to nanosphere and the amide group in P1 plays a vital role in these transition processes. Mechanical force can induce the morphology change of P1 through enhancing π–π stacking and destroying hydrogen bonds. These results demonstrate the feasibility of the design strategy for new mechanoresponsive switching materials: both π−π stacking and hydrogen bonding of the dyad contribute the mechano-induced crystalline/crystalline transformation.An amide-linked dyad with dual sensitivity of photochromism and mechanochromism is a tunable self-assembly mechanochromic material with self-assembled morphology that can be switched from fibrillar to a spherical nanostructure, accompanied with tricolor transformation, under grinding.
      PubDate: 2017-05-30T13:52:51.053963-05:
      DOI: 10.1002/adfm.201701210
       
  • XMCD and XMCD-PEEM Studies on Magnetic-Field-Assisted Self-Assembled 1D
           Nanochains of Spherical Ferrite Particles
    • Authors: Wen Zhang; Ping Kwan Johnny Wong, Dong Zhang, Jinjin Yue, Zhaoxia Kou, Gerrit van der Laan, Andreas Scholl, Jian-Guo Zheng, Zuhong Lu, Ya Zhai
      Abstract: Quasi-1D nanochains of spherical magnetic ferrite particles with a homogeneous particle size of ≈200 nm and a micrometer-sized chain length are fabricated via a self-assembly method under an external magnetic field. This assisting magnetic field (Hassist), applied during synthesis, significantly modifies the distribution of the Fe2+Oh, Fe3+Td, and Fe3+Oh cations in the chains, as demonstrated by X-ray magnetic circular dichroism (XMCD) combined with theoretical analysis. This provides direct evidence of the nontrivial role of external synthetic conditions for defining the crystal chemistry of nanoscale ferrites and in turn their magnetic properties, providing an extra degree of freedom for intentional control over the performances of 1D magnetic nanodevices for various applications. Magnetic imaging, performed via XMCD in photoemission electron microscopy, further shows the possibility of creating and trapping a series of adjacent magnetic domain walls in a single chain, suggesting that there is great application potential for these nanochains in 1D magnetic nanodevices, as determined by field- or current-driven domain wall motions. Practical control over the magnetic properties of the nanochains is also achieved by extrinsic dopants of cobalt and zinc, which are observed to occupy the ferrite ionic sites in a selective manner.Magnetic-field-assisted self-assembled 1D nanochains of spherical ferrite particles are investigated using X-ray magnetic circular dichroism (XMCD), revealing the important role of Hassist in determining the magnetic properties of nanoscale ferrites. An assisting magnetic field during synthesis (Hassist) of 2500 Oe offers a favorable fabrication condition for obtaining suitable nanochains for applications in magnetic 1D nanodevices, and the first observation on the precise pinning of domain walls is achieved via XMCD in photoemission electron microscopy (PEEM).
      PubDate: 2017-05-30T13:52:44.84337-05:0
      DOI: 10.1002/adfm.201701265
       
  • Wide Bandgap Copolymers Based on Quinoxalino[6,5-f].quinoxaline for Highly
           Efficient Nonfullerene Polymer Solar Cells
    • Authors: Ting Yu; Xiaopeng Xu, Guangjun Zhang, Jiahui Wan, Ying Li, Qiang Peng
      Abstract: Two novel wide bandgap copolymers based on quinoxalino[6,5-f]quinoxaline (NQx) acceptor block, PBDT–NQx and PBDTS–NQx, are successfully synthesized for efficient nonfullerene polymer solar cells (PSCs). The attached conjugated side chains on both benzodithiophene (BDT) and NQx endow the resulting copolymers with low-lying highest occupied molecular orbital (HOMO) levels. The sulfur atom insertion further reduces the HOMO level of PBDTS–NQx to −5.31 eV, contributing to a high open-circuit voltage, Voc, of 0.91 V. Conjugated n-octylthienyl side chains attached on the NQx skeletons also significantly improve the π–π* transitions and optical absorptions of the copolymers in the region of short wavelengths, which induce a good complementary absorption when blending with the low bandgap small molecular acceptor of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene. The wide absorption range makes the active blends absorb more photons, giving rise to a high short-circuit current density, Jsc, value of 15.62 mA cm−2. The sulfur atom insertion also enhances the crystallinity of PBDTS–NQx and presents its blend film with a favorable nanophase separation, resulting in improved Jsc and fill factor (FF) values with a high power conversion efficiency of 11.47%. This work not only provides a new fused ring acceptor block (NQx) for constructing high-performance wide bandgap copolymers but also provides the NQx-based copolymers for achieving highly efficient nonfullerene PSCs.Two novel wide bandgap copolymers based on quinoxalino[6,5-f]quinoxaline (NQx) acceptor block, PBDT–NQx and PBDTS–NQx, are successfully synthesized for efficient nonfullerene polymer solar cells. These new polymers exhibit high absorption at short wavelength, matching well with low bandgap acceptors, and have deep highest occupied molecular orbital (HOMO) levels, allowing their use in highly efficient nonfullerene solar cells with up to 11.47% power conversion efficiency.
      PubDate: 2017-05-30T13:52:28.84232-05:0
      DOI: 10.1002/adfm.201701491
       
  • Structure–Thermodynamic-Property Relationships in Cyanovinyl-Based
           Microporous Polymer Networks for the Future Design of Advanced Carbon
           Capture Materials
    • Authors: Ali Yassin; Matthias Trunk, Frank Czerny, Pierre Fayon, Abbie Trewin, Johannes Schmidt, Arne Thomas
      Abstract: Nitrogen-rich solid absorbents, which have been immensely tested for carbon dioxide capture, seem until this date to be without decisive molecular engineering or design rules. Here, a family of cyanovinylene-based microporous polymers synthesized under metal-catalyzed conditions is reported as a promising candidate for advanced carbon capture materials. These networks reveal that isosteric heats of CO2 adsorption are directly proportional to the amount of their functional group. Motivated by this finding, polymers produced under base-catalyzed conditions with tailored quantities of cyanovinyl content confirm the systematical tuning of their sorption enthalpies to reach 40 kJ mol−1. This value is among the highest reported to date in carbonaceous networks undergoing physisorption. A six-point-plot reveals that the structure–thermodynamic-property relationship is linearly proportional and can thus be perfectly fitted to tailor-made values prior to experimental measurements. Dynamic simulations show a bowl-shaped region within which CO2 is able to sit and interact with its conjugated surrounding, while theoretical calculations confirm the increase of binding sites with the increase of PhCC(CN)Ph functionality in a network. This concept presents a distinct method for the future design of carbon dioxide capturing materials.Microporous polymer networks with different cyanovinylene contents show that CO2 sorption enthalpies are directly proportional to the quantity of functional groups. As a result, affinities for carbon capture can be engineered to tailor-made values.
      PubDate: 2017-05-29T11:16:22.176778-05:
      DOI: 10.1002/adfm.201700233
       
  • Lithium Ion Breathable Electrodes with 3D Hierarchical Architecture for
           Ultrastable and High-Capacity Lithium Storage
    • Authors: Ying-Qi Li; Jian-Chen Li, Xing-You Lang, Zi Wen, Wei-Tao Zheng, Qing Jiang
      Abstract: Transition-metal oxides show genuine potential in replacing state-of-the-art carbonaceous anode materials in lithium- or sodium-ion batteries because of their much higher theoretical capacity. However, they usually undergo massive volume change, which leads to numerous problems in both material and electrode levels, such as material pulverization, instable solid-electrolyte interphase, and electrode failure. Here, it is demonstrated that lithium-ion breathable hybrid electrodes with 3D architecture tackle all these problems, using a typical conversion-type transition-metal oxide, Fe3O4, of which nanoparticles are anchored onto 3D current collectors of Ni nanotube arrays (NTAs) and encapsulated by δ-MnO2 layers (Ni/Fe3O4@MnO2). The δ-MnO2 layers reversibly switch lithium insertion/extraction of internal Fe3O4 nanoparticles and protect them against pulverizing and detaching from NTA current collectors, securing exceptional integrity retention and efficient ion/electron transport. The Ni/Fe3O4@MnO2 electrodes exhibit superior cyclability and high-capacity lithium storage (retaining ≈1450 mAh g−1, ≈96% of initial value at 1 C rate after 1000 cycles).3D lithium-ion breathable hybrid electrodes are successfully constructed by anchoring Fe3O4 nanoparticles onto highly conductive 3D current collectors of Ni nanotube arrays and encapsulating them with reversibly switching δ-MnO2 layers. As a result of integrity retention and efficient ion/electron transport, the Ni/Fe3O4@MnO2 electrodes exhibit superior cyclability and high-capacity lithium storage.
      PubDate: 2017-05-29T11:15:58.68959-05:0
      DOI: 10.1002/adfm.201700447
       
  • Cubic Perovskite Fluoride as Open Framework Cathode for Na-Ion Batteries
    • Authors: Dunping Cao; Congling Yin, Dingren Shi, Zhengwen Fu, Jincang Zhang, Chilin Li
      Abstract: Exploring novel structure prototype and mineral phase, especially open framework material, is crucial to developing high-performance Na-ion battery cathodes in view of potentially faster intrinsic diffusion of Na+ in lattices. Perovskite phases have been widely applied in solar cells, fuel cells, and electrocatalysis; however, they are rarely attempted as energy storage electrode materials. This study proposes pre-expanding perovskite iron fluoride (KFeF3) framework by stuffing large-sized K+ as a channel filler, which is advantageous over Na+, NH4+, and H2O molecule filler in terms of structure robustness, symmetry, and connectivity. K+ stuffing leads to the preservation of a more “regular” cubic phase with fast isotropic 3D diffusion as a consequence of no distortion of FeF6 octahedra during K-Na electrochemical exchange and following Na-insertion cycling. High-rate Na-storage is achievable with a reversible capacity of 110, 70, and 40 mAh g−1 at 0.1, 2, and 10 C, respectively, for this open framework fluoride cathode, benefiting from solid solution electrochemical behavior and high intrinsic diffusion coefficient. It is thought that this rate performance is currently the best among Na-storage fluoride materials.Pervoskite iron fluoride (KFeF3) of open framework is proposed as a high-rate Na-ion battery cathode. Prestuffing large-sized K+ into channels leads to the preservation of cubic phase with fast isotropic 3D diffusion as a consequence of no distortion of FeF6 octahedra during first K-extraction and following Na-storage cycling.
      PubDate: 2017-05-29T11:15:51.942814-05:
      DOI: 10.1002/adfm.201701130
       
  • The Impact of Sequential Fluorination of π-Conjugated Polymers on Charge
           Generation in All-Polymer Solar Cells
    • Authors: Kakaraparthi Kranthiraja; Seonha Kim, Changyeon Lee, Kumarasamy Gunasekar, Vijaya Gopalan Sree, Bhoj Gautam, Kenan Gundogdu, Sung-Ho Jin, Bumjoon J. Kim
      Abstract: The performance of all-polymer solar cells (all-PSCs) is often limited by the poor exciton dissociation process. Here, the design of a series of polymer donors (P1–P3) with different numbers of fluorine atoms on their backbone is presented and the influence of fluorination on charge generation in all-PSCs is investigated. Sequential fluorination of the polymer backbones increases the dipole moment difference between the ground and excited states (Δµge) from P1 (18.40 D) to P2 (25.11 D) and to P3 (28.47 D). The large Δµge of P3 leads to efficient exciton dissociation with greatly suppressed charge recombination in P3-based all-PSCs. Additionally, the fluorination lowers the highest occupied molecular orbital energy level of P3 and P2, leading to higher open-circuit voltage (VOC). The power conversion efficiency of the P3-based all-PSCs (6.42%) outperforms those of the P2 and P1 (5.00% and 2.65%)-based devices. The reduced charge recombination and the enhanced polymer exciton lifetime in P3-based all-PSCs are confirmed by the measurements of light-intensity dependent short-circuit current density (JSC) and VOC, and time-resolved photoluminescence. The results provide reciprocal understanding of the charge generation process associated with Δµge in all-PSCs and suggest an effective strategy for designing π-conjugated polymers for high performance all-PSCs.An efficient approach for achieving high-performance all-polymer solar cells (all-PSCs) is demonstrated by controlling the dipole moment of polymers (P1–P3) via sequential fluorination on polymer backbones. P3-based all-PSCs with large dipole moments produce a greatly enhanced power conversion efficiency of 6.42%, which is well-correlated with efficient charge generation including improved exciton dissociation efficiency, reduced charge recombination, and enhanced lifetime of excitons.
      PubDate: 2017-05-29T11:15:44.60393-05:0
      DOI: 10.1002/adfm.201701256
       
  • Room-Temperature Dielectric Switchable Nanocomposites
    • Authors: Peng Meng; Quan Zhang, Yulong Wu, Zhiyuan Tan, Guoan Cheng, Xiaoling Wu, Ruiting Zheng
      Abstract: Room-temperature switchable dielectric materials are of interest for many applications, including solar energy storage, smart switches, automatic filters, and next-generation sensors. Here, a temperature-triggered dielectric switchable nanocomposite by dispersing octadecylamine-grafted multiwalled carbon nanotubes (ODA-MWCNTs, for short) into hexadecane is reported. The composite has low permittivity at molten state and high permittivity at frozen state, and the permittivity switch is triggered around 18 °C. The highest permittivity contrast ratio reaches 106.4 at 2.0% CNT volume fraction. The composite shows frequency-sensitive and temperature-ramping-rate-sensitive properties. Further investigation indicates that the permittivity switch is caused by the change of the ODA-MWCNT percolating networks during phase transition.A novel room-temperature dielectric switchable material is obtained by octadecylamine-grafted multiwalled carbon nanotubes (ODA-MWCNTs)/hexadecane composites. The distinct switchable behavior is caused by the microstructure evolution of ODA-MWCNTs when the matrix phase changes. The switch is triggered around 18 °C and the permittivity switching ratio can reach 106.4 times.
      PubDate: 2017-05-29T11:15:38.230283-05:
      DOI: 10.1002/adfm.201701136
       
  • Rapid and Scalable Synthesis of Mo-Based Binary and Ternary Oxides for
           Electrochemical Applications
    • Authors: Gan Qu; Tianqi Li, Shuangfeng Jia, He Zheng, Lei Li, Fan Cao, Hai Wang, Wenhao Ma, Yiwen Tang, Jianbo Wang
      Abstract: Mo-based binary oxides (MBOs) and Mo-based ternary oxides (MTOs) are a research focus because of their widespread applications. The traditional synthesis routes for MBOs and MTOs require high temperature and are time intense. Here, a rapid, facile, and scalable strategy to efficiently fabricate MBOs and MTOs with various morphologies and crystal structures is reported. Only 1 min is required for the whole process and the yield is above 90%. This strategy is the simplest and the fastest method reported and exhibits large potential for application. Furthermore, the as-synthesized HxMoO3 nanobelts and NiMoO4·xH2O nanowires display a specific capacitance of 660.3 F g−1 at 2 mV s−1 and a specific capacity of 549 C g−1 at 1 A g−1. In addition, to assemble the HxMoO3 and NiMoO4·xH2O electrodes together, the solid state hybrid electrolyte is employed to take advantage of MBOs and MTOs. The obtained NiMoO4·xH2O//HxMoO3 device delivers a specific capacitance of 156 F g−1 at 0.8 A g−1 and an energy density of 55.6 Wh kg−1 at a power density of 640 W kg−1, making it attractive for application as an energy storage material.A facile strategy to fabricate Mo-based binary oxides and Mo-based ternary oxides simultaneously is reported. This strategy exhibits large potential for industrialization. Moreover, the obtained HxMoO3 nanobelts and NiMoO4·xH2O nanowires display outstanding electrochemical performance, acting as negative and positive electrodes correspondingly. Consequently, the assembled NiMoO4·xH2O//HxMoO3 device delivers superior energy storage performance.
      PubDate: 2017-05-29T11:15:34.454327-05:
      DOI: 10.1002/adfm.201700928
       
  • Reversible Quadruple Switching with Optical, Chiroptical, Helicity, and
           Macropattern in Self-Assembled Spiropyran Gels
    • Authors: Wangen Miao; Sheng Wang, Minghua Liu
      Abstract: Enantiomeric glutamate gelators containing a spiropyran moiety are designed and found to self-assemble into a nanohelix through gelation. Upon alternating UV and visible light irradiation, the spiropyran experiences a reversible change between a blue zwitterionic merocyanine state and a colorless closed ring state spiropyran in supramolecular gels. This photochromic switch causes a series of subsequent changes in the optical, chiroptical, morphological properties from supramolecular to macroscopic levels. While the solution of the gelator molecules does not show any circular dichroism (CD) signal in the region of 250–700 nm due to the fact that the chromophore is far from the chiral center, the gel shows chiroptical signals such as CD and circularly polarized luminescence (CPL) because of the chirality transfer by the self-assembly. These signals are reversible upon alternating UV/vis irradiation. Therefore, a quadruple optical and chiroptical switch is developed successfully. During such process, the self-assembled nanostructures from the enantiomeric supramolecular gels also undergo a reversible change between helices and fibers under the alternating UV and visible light trigger. Furthermore, a rewritable material fabricated from their xerogels on a glass is developed. Such rewritable material can be efficiently printed over 30 cycles without significant loss in contrast and resolution using UV and visible light.A reversible quadruple optical and chiroptical switch that is responsive to photochromism, fluorescence, chiroptics, and circularly polarized luminescence (CPL) is developed based on the enantiomeric spiropyran gels. It responds to stimuli of alternating UV and visible light. Moreover, the xerogels can be fabricated as rewritable materials.
      PubDate: 2017-05-29T11:11:14.841609-05:
      DOI: 10.1002/adfm.201701368
       
  • Using Coordination Assembly as the Microencapsulation Strategy to Promote
           the Efficacy and Environmental Safety of Pyraclostrobin
    • Authors: Bei-xing Li; Wei-chang Wang, Xian-peng Zhang, Da-xia Zhang, Yu-peng Ren, Yun Gao, Wei Mu, Feng Liu
      Abstract: The broad-spectrum and widely used fungicide pyraclostrobin is encapsulated using a coordination assembly between Fe3+ and tannic acid to promote its efficacy and environmental safety. The deposition is confirmed by the surface zeta potential and energy dispersive spectroscopy. Optical microscopy, scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM) observations are integrated to characterize the pyraclostrobin-loaded microcapsules (MCs). These MCs retain a spherical shape when suspended in water but quickly deform or rupture after the water evaporates when deposited for 1 cycle. After sequential deposition of the membrane, the membrane thickness increases linearly according to TEM and AFM height analyses. These MCs show satisfactory efficacy on rice blast, resulting in significantly higher yields at doses of 120 and 180 g ha−1. Moreover, these MCs display significantly lower toxicity to Brachydanio rerio, Daphnia magna, Xenopus laevis, and Rana nigromaculata. Overall, this novel microencapsulation strategy is capable of promoting the efficacy and environmental safety of pyraclostrobin.A fungicide pyraclostrobin is encapsulated using coordination assembly between Fe3+ and tannic acid. The membrane thickness increases linearly after sequential deposition, as determined using transmission electron microscopy and atomic force microscopy. These microcapsules show satisfactory efficacy on rice blast and display significantly lower toxicity to Brachydanio rerio, Daphnia magna, Xenopus laevis, and Rana nigromaculata than that of pyraclostrobin emulsifiable concentrate.
      PubDate: 2017-05-29T11:11:07.500897-05:
      DOI: 10.1002/adfm.201701841
       
  • Plasmonic-Tuned Flash Cu Nanowelding with Ultrafast Photochemical-Reducing
           and Interlocking on Flexible Plastics
    • Authors: Jung Hwan Park; Seungyong Han, Dongkwan Kim, Byoung Kuk You, Daniel J. Joe, Sukjoon Hong, Jeongmin Seo, Jinhyeong Kwon, Chang Kyu Jeong, Hong-Jin Park, Taek-Soo Kim, Seung Hwan Ko, Keon Jae Lee
      Abstract: Herein, a high-performance copper nanowire (Cu NW) network (sheet resistance ≈ 17 Ω sq−1, transmittance 88%) fabricated by plasmonic-tuned flash welding (PFW) with ultrafast interlocking and photochemical reducing is reported, which greatly enhance the mechanical and chemical stability of Cu NWs. Xenon flash spectrum is tuned in an optimized distribution (maximized light intensity at 600 nm wavelength) through modulation of electron kinetic energy in the lamp by generating drift potential for preferential photothermal interactions. High-intensity visible light is emitted by the plasmonic-tuned flash, which strongly improves Cu nanowelding without oxidation. Near-infrared spectrum of the flash induced an interlocking structure of NW/polyethylene terephthalate interface by exciting Cu NW surface plasmon polaritons (SPPs), increasing adhesion of the Cu nanonetwork by 208%. In addition, ultrafast photochemical reduction of Cu NWs is accomplished in air by flash-induced electron excitations and relevant chemical reactions. The PFW effects of localized surface plasmons and SPPs on junction welding and adhesion strengthening of Cu network are theoretically studied as physical behaviors by finite-difference time-domain simulations. Finally, a transparent resistive memory and a touch screen panel are demonstrated by using the flash-induced Cu NWs, showing versatile and practical uses of PFW-treated Cu NW electrodes for transparent flexible electronics.Plasmonic-tuned flash copper (Cu) nanowelding is developed for high-performance Cu nanowires (NWs) with interlocking on plastics. In addition, rapid photochemical reduction of oxidized Cu NWs is demonstrated in air. Finally, a transparent resistive memory and a touch screen panel are fabricated by using the Cu NWs.
      PubDate: 2017-05-29T10:56:20.287222-05:
      DOI: 10.1002/adfm.201701138
       
  • Wafer-Scale Single-Crystalline Ferroelectric Perovskite Nanorod Arrays
    • Authors: Min Gyu Kang; Seul-Yi Lee, Deepam Maurya, Christopher Winkler, Hyun-Cheol Song, Robert B. Moore, Mohan Sanghadasa, Shashank Priya
      Abstract: 1D ferroelectric nanostructures are promising for enhanced ferroelectric and piezoelectric performance on the nanoscale, however, their synthesis at the wafer scale using industrially compatible processes is challenging. In order to advance the nanostructure-based electronics, it is imperative to develop a silicon-compatible growth technique yielding high volumetric density and an ordered arrangement. Here, a major breakthrough is provided in addressing this need and ordered and close-packed single crystalline ferroelectric nanorod arrays, of composition PbZr0.52Ti0.48O3 (PZT), grown on commercial grade 3 in. silicon wafer are demonstrated. PZT nanorods exhibit enhanced piezoelectric and ferroelectric performance compared to thin films of similar dimensions. Sandwich structured architecture utilizing 1D PZT nanorod arrays and 2D reduced graphene oxide thin film electrodes is fabricated to provide electrical connection. Combined, these results offer a clear pathway toward integration of ferroelectric nanodevices with commercial silicon electronics.Ordered and close-packed single crystalline ferroelectric nanorod arrays are successfully synthesized on commercial grade Si wafer. Reduced graphene oxide thin film electrodes are integrated on ferroelectric nanorod arrays to demonstrate nanostructured electronics. Nanorods covering the full 3 in. wafer exhibit 1D confined ferroelectric domain switching and enhanced longitudinal piezoelectric performance.
      PubDate: 2017-05-29T10:56:07.803619-05:
      DOI: 10.1002/adfm.201701542
       
  • Multimodal Magnetic Nanoclusters for Gene Delivery, Directed Migration,
           and Tracking of Stem Cells
    • Authors: Ji Sun Park; Wooram Park, Sin-jung Park, Andrew C. Larson, Dong-Hyun Kim, Keun-Hong Park
      Abstract: This study develops multimodal magnetic nanoclusters (M-MNCs) for gene transfer, directed migration, and tracking of human mesenchymal stem cells (hMSCs). The M-MNCs are designed with 5 nm iron oxide nanoparticles and a fluorescent dye (i.e., Rhodamine B) in the matrix of the Food and Drug Administration approved polymer poly(lactide-co-glycolide) using a nanoemulsion method. The synthesized M-MNCs have a hydrodynamic diameter of ≈150 nm, are internalized by stem cells via endocytosis, and deliver genes with high efficiency. The cellular internalization and gene expression efficiency of the clustered nanoparticles are significantly higher than that of single nanoparticles. The M-MNC-labeled hMSCs migrate upon application of a magnetic force and can be visualized by both optical and magnetic resonance (MR) imaging. In animal models, the M-MNC-labeled hMSCs are also successfully tracked using optical and MR imaging. Thus, the M-MNCs not only allow the efficient delivery of genes to stem cells but also the tracking of cells in animal models. Taken together, the results show that this new type of nanocomposite can be of great help in future stem cell research and in the development of cell-based therapeutic agents.Multimodal magnetic nanoclusters (M-MNCs) for gene delivery, directed migration, and tracking of stem cells are developed through an easy nanoemulsion method. The M-MNCs show high transfection efficacy and allow directed migration of the stem cells under magnetic fields and provide multimodal imaging modality to enable tracking of the stem cells.
      PubDate: 2017-05-29T10:55:53.866738-05:
      DOI: 10.1002/adfm.201700396
       
  • Tunable Gas Sensing Gels by Cooperative Assembly
    • Authors: Abid Hussain; Ana T. S. Semeano, Susana I. C. J. Palma, Ana S. Pina, José Almeida, Bárbara F. Medrado, Ana C. C. S. Pádua, Ana L. Carvalho, Madalena Dionísio, Rosamaria W. C. Li, Hugo Gamboa, Rein V. Ulijn, Jonas Gruber, Ana C. A. Roque
      Abstract: The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels' structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli.Self-assembled hybrid gels result from the unconventional combination of functional components, liquid crystals for reporting, ionic liquid as solvent, biopolymer as matrix, giving rise to molecular recognition properties not seen in the individual components. Thin films prepared from the gels are robust and exhibit dual optical/electrical stimuli-responsive properties in the presence of gases.
      PubDate: 2017-05-29T04:44:40.348737-05:
      DOI: 10.1002/adfm.201700803
       
  • Enhancing Ion Migration in Grain Boundaries of Hybrid Organic–Inorganic
           Perovskites by Chlorine
    • Authors: Bin Yang; Chance C. Brown, Jingsong Huang, Liam Collins, Xiahan Sang, Raymond R. Unocic, Stephen Jesse, Sergei V. Kalinin, Alex Belianinov, Jacek Jakowski, David B. Geohegan, Bobby G. Sumpter, Kai Xiao, Olga S. Ovchinnikova
      Abstract: Ionicity plays an important role in determining material properties, as well as optoelectronic performance of organometallic trihalide perovskites (OTPs). Ion migration in OTP films has recently been under intensive investigation by various scanning probe microscopy (SPM) techniques. However, controversial findings regarding the role of grain boundaries (GBs) associated with ion migration are often encountered, likely as a result of feedback errors and topographic effects common in to SPM. In this work, electron microscopy and spectroscopy (scanning transmission electron microscopy/electron energy loss spectroscopy) are combined with a novel, open-loop, band-excitation, (contact) Kelvin probe force microscopy (BE-KPFM and BE-cKPFM), in conjunction with ab initio molecular dynamics simulations to examine the ion behavior in the GBs of CH3NH3PbI3 perovskite films. This combination of diverse techniques provides a deeper understanding of the differences between ion migration within GBs and interior grains in OTP films. This work demonstrates that ion migration can be significantly enhanced by introducing additional mobile Cl− ions into GBs. The enhancement of ion migration may serve as the first step toward the development of high-performance electrically and optically tunable memristors and synaptic devices.By combining a novel, open-loop, band-excitation, contact Kelvin probe force microscopy, in conjunction with ab initio molecular dynamics simulations, it is demonstrated that ion migration can be significantly enhanced by introducing additional mobile chloride ions into grain boundaries of CH3NH3PbI3 perovskite films. This may serve as the first step toward the development of high-performance electrically and optically tunable memristors and synaptic devices.
      PubDate: 2017-05-26T00:46:36.988209-05:
      DOI: 10.1002/adfm.201700749
       
  • High Electroactive Material Loading on a Carbon Nanotube@3D Graphene
           Aerogel for High-Performance Flexible All-Solid-State Asymmetric
           Supercapacitors
    • Authors: Zhenghui Pan; Meinan Liu, Jie Yang, Yongcai Qiu, Wanfei Li, Yan Xu, Xinyi Zhang, Yuegang Zhang
      Abstract: Freestanding carbon-based hybrids, specifically carbon nanotube@3D graphene (CNTs@3DG) hybrid, are of great interest in electrochemical energy storage. However, the large holes (about 400 µm) in the commonly used 3D graphene foams (3DGF) constitute as high as 90% of the electrode volume, resulting in a very low loading of electroactive materials that is electrically connected to the carbon, which makes it difficult for flexible supercapacitors to achieve high gravimetric and volumetric energy density. Here, a hierarchically porous carbon hybrid is fabricated by growing 1D CNTs on 3D graphene aerogel (CNTs@3DGA) using a facile one-step chemical vapor deposition process. In this architecture, the 3DGA with ample interconnected micrometer-sized pores (about 5 µm) dramatically enhances mass loading of electroactive materials comparing with 3DGF. An optimized all-solid-state asymmetric supercapacitor (AASC) based on MnO2@CNTs@3DGA and Ppy@CNTs@3DGA electrodes exhibits high volumetric energy density of 3.85 mW h cm−3 and superior long-term cycle stability with 84.6% retention after 20 000 cycles, which are among the best reported for AASCs with both electrodes made of pseudocapacitive electroactive materials.A simple, scalable, and environmentally friendly method is described for preparing a novel carbon nanotube (CNT)@3D graphene aerogel (3DGA) that acts as an ideal support for high loading of electroactive materials. Lightweight and flexible all-solid-state asymmetric supercapacitors are assembled from the MnO2@CNTs@3DGA and polypyrrole@CNTs@3DGA electrodes. The devices realize high areal capacitance and superior mechanical strength and hold great promise for future flexible electronics.
      PubDate: 2017-05-26T00:46:33.393282-05:
      DOI: 10.1002/adfm.201701122
       
  • Conductive Metal–Organic Framework Nanowire Array Electrodes for
           High-Performance Solid-State Supercapacitors
    • Authors: Wen-Hua Li; Kui Ding, Han-Rui Tian, Ming-Shui Yao, Bhaskar Nath, Wei-Hua Deng, Yaobing Wang, Gang Xu
      Abstract: The application of conventional metal–organic frameworks (MOFs) as electrode materials in supercapacitors is largely hindered by their conventionally poor electrical conductivity. This study reports the fabrication of conductive MOF nanowire arrays (NWAs) and the application of them as the sole electrode material for solid-state supercapacitors. By taking advantage of the nanostructure and making full use of the high porosity and excellent conductivity, the MOF NWAs in solid-state supercapacitor show the highest areal capacitance and best rate performance of all reported MOF materials for supercapacitors, which is even comparable to most carbon materials.Conductive metal–organic framework (MOF) nanowire arrays (NWAs) are prepared as the sole electrode material for solid-state supercapacitors. By taking advantage of their nanostructure and making full use of the high porosity and excellent conductivity, the MOF NWAs in the solid-state supercapacitor show the highest areal capacitance and best rate performance of all reported MOF materials.
      PubDate: 2017-05-26T00:46:26.992477-05:
      DOI: 10.1002/adfm.201702067
       
  • A Ratiometric Near-Infrared Fluorescent Probe for Quantification and
           Evaluation of Selenocysteine-Protective Effects in Acute Inflammation
    • Authors: Xiaoyue Han; Xinyu Song, Fabiao Yu, Lingxin Chen
      Abstract: Selenocysteine (Sec) is a primary kind of reactive selenium species in cells whose antioxidant roles in a series of liver diseases have been featured. However, it is difficult to determine Sec in living cells and in vivo due to its high reactivity and instability. This work reports a ratiometric near-infrared fluorescent probe (Cy-SS) for qualitative and quantitative determination of Sec in living cells and in vivo. The probe is composed of heptamethine cyanine fluorophore, the response unit bis(2-hydroxyethyl) disulfide, and the liver-targeting moiety d-galactose. Based on a detection mechanism of selenium–sulfur exchange reaction, the concentrations of Sec in HepG2, HL-7702 cells, and primary mouse hepatocytes is determined as 3.08 ± 0.11 × 10−6m, 4.03 ± 0.16 × 10−6m and 4.34 ± 0.30 × 10−6m, respectively. The probe can selectively accumulate in liver. The ratio fluorescence signal of the probe can be employed to quantitatively analyze the fluctuation of Sec concentrations in cells and mice models of acute hepatitis. The experimental results demonstrate that Sec plays important antioxidant and anti-inflammatory roles during inflammatory process. And the levels of intracellular Sec have a close relationship with the degree of liver inflammation. The above imaging detections make this new probe a potential candidate for the accurate diagnosis of inflammation.A ratiometric near-infrared fluorescent probe (Cy-SS) is developed for qualitative and quantitative detection of selenocysteine (Sec) in living cells and in vivo. The probe is used to target the liver and detect Sec concentrations in normal and acute hepatitis BALB/c mice models. Sec is critical to maintain the redox statues of the liver and protect liver from inflammatory injury.
      PubDate: 2017-05-24T01:00:40.720989-05:
      DOI: 10.1002/adfm.201700769
       
  • Phase and Composition Tuning of 1D Platinum-Nickel Nanostructures for
           Highly Efficient Electrocatalysis
    • Authors: Kezhu Jiang; Qi Shao, Dandan Zhao, Lingzheng Bu, Jun Guo, Xiaoqing Huang
      Abstract: Among various platinum (Pt)-based nanostructures, porous or hollow ones are of great importance because they exhibit fantastic oxygen reduction reaction (ORR) enhancements and maximize atomic utilization by exposing both exterior and interior surfaces. Here, a new class of porous Pt3Ni nanowires (NWs) with 1D architecture, an ultrathin Pt-rich shell, high index facets, and a highly open structure is designed via a selective etching strategy by using the phase and composition segregated Pt-Ni NWs as the starting material. The porous feature of Pt3Ni NWs can be readily fulfilled by changing the Pt/Ni atomic ratio of the starting Pt-Ni NWs. Such porous Pt3Ni NWs show extraordinary activity and stability enhancements toward methanol oxidation reaction and ORR. The porous Pt3Ni NWs can deliver ORR mass activity of 5.60 A mg−1, which is 37.3-fold higher than that of the Pt/C. They also show outstanding stability with negligible activity loss after 20 000 cycles. This study offers a unique approach for the design of complex nanostructures as efficient catalysts through precisely tailoring.Porous Pt3Ni nanowires (NWs) are obtained by selectively etching Pt-Ni NWs with phase and component control. Due to their unique structure of high index facets, highly open structure, 1D structure, and ultrathin Pt-rich surface, the resulting porous Pt3Ni NWs show extraordinary activity and stability toward the oxygen reduction reaction, suggesting that superior Pt-based catalysts can be developed by precisely tailoring.
      PubDate: 2017-05-24T01:00:33.289428-05:
      DOI: 10.1002/adfm.201700830
       
  • Screening of Nanocomposite Scaffolds Arrays Using
           Superhydrophobic-Wettable Micropatterns
    • Authors: Álvaro J. Leite; Mariana B. Oliveira, Sofia G. Caridade, João F. Mano
      Abstract: Platforms containing multiple arrays for high-throughput screening are demanded in the development of biomaterial libraries. Here, an array platform for the combinatorial analysis of cellular interactions and 3D porous biomaterials is described. Using a novel method based on computer-aided manufacturing, wettable regions are printed on superhydrophobic surfaces, generating isolated spots. This freestanding benchtop array is used as a tool to deposit naturally derived polymers, chitosan and hyaluronic acid, with bioactive glass nanoparticles (BGNPs) to obtain a scaffold matrix. The effect of fibronectin adsorption on the scaffolds is also tested. The biomimetic nanocomposite scaffolds are shown to be osteoconductive, non-cytotoxic, promote cell adhesion, and regulate osteogenic commitment. The method proves to be suitable for screening of biomaterials in 3D cell cultures as it can recreate a multitude of combinations on a single platform and identify the optimal composition that drives to desired cell responses. The platforms are fully compatible with commercially routine cell culture labware and established characterization methods, allowing for a standard control and easy adaptability to the cell culture environment. This study shows the value of 3D structured array platforms to decode the combinatorial interactions at play in cell microenvironments.Superhydrophobic surfaces patterned with wettable spots offer the advantages of benchtop array formation for 3D cell cultures and high-throughput screening. The arrays are suitable for characterization of nanocomposite scaffolds. Moreover, they are compatible with cell culture labware and established characterization methods, allowing standardization and adaptability. This study unveils the synergy between nanocomposites and cell behavior to develop biomaterial libraries.
      PubDate: 2017-05-24T00:55:57.072931-05:
      DOI: 10.1002/adfm.201701219
       
  • Supramolecular-Assembled Nanoporous Film with Switchable Metal Salts for a
           Triboelectric Nanogenerator
    • Authors: Chanho Park; Giyoung Song, Suk Man Cho, Jihoon Chung, Yujeong Lee, Eui Hyuk Kim, Minjoo Kim, Sangmin Lee, June Huh, Cheolmin Park
      Abstract: A triboelectric nanogenerators (TENG) are of great interest as emerging power harvesters because of their simple device architecture with unprecedented high efficiency. Despite the substantial development of new constituent materials and device architectures, a TENG with a switchable surface on a single device, which allows for facile control of the triboelectric output performance, remains a challenge. Here, a supramolecular route for fabricating a novel TENG based on an alkali-metal-bound porous film, where the alkali metal ions are readily switched among one another is demonstrated. The soft nanoporous TENG contains numerous SO3− groups on the surface of nanopores prepared from the supramolecular assembly of sulfonic-acid-terminated polystyrene and poly(2-vinylpyridine) (P2VP), followed by soft etching of P2VP. Selective binding of alkali metal ions, including Li+, Na+, K+, and Cs+, with SO3− groups enables the development of mechanically robust alkali-metal-ion-decorated TENGs. The triboelectric output performance of the devices strongly depends on the alkali metal ion species, and the output power ranges from 11.5 to 256.5 µW. This wide-range triboelectric tuning can be achieved simply by a conventional ion exchange process in a reversible manner, thereby allowing reversible control of the output performance in a single device platform.A supramolecular route for the fabrication of surface-tunable triboelectric nanogenerators is developed. The method is based on a nanoporous surface capable of binding with alkali metal ions, which are readily switchable among one another, via a conventional ion exchange process. This allows for the repeated and reversible switching of the triboelectric properties in a single device platform.
      PubDate: 2017-05-24T00:55:45.470924-05:
      DOI: 10.1002/adfm.201701367
       
  • Oxygen Vacancies Evoked Blue TiO2(B) Nanobelts with Efficiency Enhancement
           in Sodium Storage Behaviors
    • Authors: Yan Zhang; Zhiying Ding, Christopher W. Foster, Craig E. Banks, Xiaoqing Qiu, Xiaobo Ji
      Abstract: Oxygen vacancies (OVs) dominate the physical and chemical properties of metal oxides, which play crucial roles in the various fields of applications. Density functional theory calculations show the introduction of OVs in TiO2(B) gives rise to better electrical conductivity and lower energy barrier of sodiation. Here, OVs evoked blue TiO2(B) (termed as B-TiO2(B)) nanobelts are successfully designed upon the basis of electronically coupled conductive polymers to TiO2, which is confirmed by electron paramagnetic resonance and X-ray photoelectron spectroscopy. The superiorities of OVs with the aid of carbon encapsulation lead to higher capacity (210.5 mAh g−1 (B-TiO2(B)) vs 102.7 mAh g−1 (W-TiO2(B)) at 0.5 C) and remarkable long-term cyclability (the retention of 94.4% at a high rate of 10 C after 5000 times). In situ X-ray diffractometer analysis spectra also confirm that an enlarged interlayer spacing stimulated by OVs is beneficial to accommodate insertion and removal of sodium ions to accelerate storage kinetics and preserve its original crystal structure. The work highlights that injecting OVs into metal oxides along with carbon coating is an effective strategy for improving capacity and cyclability performances in other metal oxide based electrochemical energy systems.Oxygen vacancies (OVs) evoked blue-colored TiO2(B) nanobelts are first designed as superior anodes for sodium-ion batteries. They feature remarkable high-rate performance and durable long-term cycle life because of their ability to take full advantage of OVs to elevate electronic conductivity and lower sodiated energy barriers. A high capacity of 80.9 mAh g−1 (at 3350 mA g−1) is still maintained after 5000 cycles.
      PubDate: 2017-05-24T00:55:35.461368-05:
      DOI: 10.1002/adfm.201700856
       
  • Bottom-Up Preparation of Uniform Ultrathin Rhenium Disulfide Nanosheets
           for Image-Guided Photothermal Radiotherapy
    • Authors: Sida Shen; Yu Chao, Ziliang Dong, Guanglin Wang, Xuan Yi, Guosheng Song, Kai Yang, Zhuang Liu, Liang Cheng
      Abstract: Facile preparation of multifunctional theranostic nanoplatforms with well-controlled morphology and sizes remains an attractive in the area of nanomedicine. Here, a new kind of 2D transition metal dichalcogenide, rhenium disulfide (ReS2) nanosheets, with uniform sizes, strong near-infrared (NIR) light, and strong X-ray attenuation, is successfully synthesized. After surface modification with poly(ethylene glycol) (PEG), the synthesized ReS2-PEG nanosheets are stable in various physiological solutions. In addition to their contrasts in photoacoustic imaging and X-ray computed tomography imaging because of their strong NIR light and X-ray absorptions, respectively, such ReS2-PEG nanosheets can also be tracked under nuclear imaging after chelator-free labeling with radioisotope ions, 99mTc4+. Efficient tumor accumulation of ReS2-PEG nanosheets is then observed after intravenous injection into tumor-bearing mice under triple-modal imaging. The combined in vivo photothermal radiotherapy is further conducted, achieving a remarkable synergistic tumor destruction effect. Finally, no obvious toxicity of ReS2-PEG nanosheets is observed from the treated mice within 30 d. This work suggests that such ultrathin ReS2 nanosheets with well-controlled morphology and uniform sizes may be a promising type of multifunctional theranostic agent for remotely triggered cancer combination therapy.A one-step bottom-up method is developed to synthesize a new kind of transition metal dichalcogenide (TMDC), rhenium disulfide (ReS2), with well-defined 2D nanosheet morphology and uniform sizes, for multimodal imaging-guided cancer combination therapy.
      PubDate: 2017-05-23T01:40:40.824783-05:
      DOI: 10.1002/adfm.201700250
       
  • A Patterned Graphene/ZnO UV Sensor Driven by Integrated Asymmetric
           Micro-Supercapacitors on a Liquid Metal Patterned Foldable Paper
    • Authors: Junyeong Yun; Yein Lim, Hanchan Lee, Geumbee Lee, Heun Park, Soo Yeong Hong, Sang Woo Jin, Yong Hui Lee, Sang-Soo Lee, Jeong Sook Ha
      Abstract: A foldable array of patterned graphene/ZnO nanoparticle UV sensor and asymmetric micro-supercapacitors (AMSCs) integrated on a paper substrate with patterned liquid metal interconnections is reported. The resistor type UV sensor based on graphene/ZnO nanoparticles is patterned to be driven by the stored energy of the integrated AMSCs. The AMSC consists of MnO2 nanoball deposited multiwalled carbon nanotubes (MWNTs) and V2O5 wrapped MWNTs as positive and negative electrodes, respectively. As an electrolyte, propylene carbonate-poly(methyl methacrylate)-LiClO4, an organic solvent-based gel, is used. The UV sensor and AMSCs can be easily integrated on a liquid metal, Galinstan, patterned, waterproof mineral paper and show a mechanically stable UV sensing, regardless of repetitive folding cycles. This work demonstrates a novel foldable nanomaterial based sensor system driven by integrated energy storage devices, applicable to future wearable and portable electronics.A patterned graphene/ZnO UV sensor driven by integrated asymmetric micro-supercapacitors (AMSCs) on a liquid metal patterned foldable substrate is demonstrated. With the stored energy of the AMSCs, the integrated UV sensor is operated stable for 1500 s under deformations of folding.
      PubDate: 2017-05-23T01:10:44.107163-05:
      DOI: 10.1002/adfm.201700135
       
  • Holey Carbon Nanotubes from Controlled Air Oxidation
    • Authors: Yi Lin; Michael R. Funk, Caroline J. Campbell, Jae-Woo Kim, Xiaogang Han, Steven D. Lacey, Hua Xie, Liangbing Hu, John W. Connell
      Abstract: Defects in various nanomaterials are often desirable to enable enhanced functional group attachments and attain properties that are not available with their intact counterparts. A new paradigm in the defective low-dimensional carbon nanomaterials is to create holes on the graphitic surfaces via partial etching. For example, holey graphene, graphene sheets with through-thickness holes, is synthesized using several different partial etching approaches and found useful for various applications such as field-effect transistors, sensors, energy storage devices, and separation membranes. In these applications, the presence of holes leads to unique advantages, such as bandgap widening, chemical functionalization of hole edges, and improved accessible surface area. Here, a facile and scalable method to prepare holey carbon nanotubes via controlled air oxidation is presented. Although no additional catalyst is added, the residual iron nanocatalysts encapsulated in the nanotube cavity from nanotube manufacturing significantly contributed to the hole generation through the nanotube walls. The holey carbon nanotube products exhibit enhanced surface area, pore volume, and oxygen-containing functional groups, which lead to their much enhanced electrochemical capacitive properties (increased over 100% in capacitance). Synthesis and characterization details of this novel class of holey carbon nanomaterials are presented, and their potential applications are discussed.Holey carbon nanotubes are prepared by partial thermal oxidation of multiwalled carbon nanotubes in air. This facile process results in holes through the tubular walls along the nanotube body. With much increased accessible surface area and pore volume, the electrochemical capacitive performances of holey carbon nanotubes become significant enhanced compared to untreated nanotubes.
      PubDate: 2017-05-22T07:20:37.111376-05:
      DOI: 10.1002/adfm.201700762
       
  • An Interdiffusion Method for Highly Performing Cesium/Formamidinium Double
           Cation Perovskites
    • Authors: Weiming Qiu; Aniruddha Ray, Manoj Jaysankar, Tamara Merckx, Joao P. Bastos, David Cheyns, Robert Gehlhaar, Jef Poortmans, Paul Heremans
      Abstract: The fabrication of high-quality cesium (Cs)/formamidinium (FA) double-cation perovskite films through a two-step interdiffusion method is reported. CsxFA1-xPbI3-y(1-x)Bry(1-x) films with different compositions are achieved by controlling the amount of CsI and formamidinium bromide (FABr) in the respective precursor solutions. The effects of incorporating Cs+ and Br− on the properties of the resulting perovskite films and on the performance of the corresponding perovskite solar cells are systematically studied. Small area perovskite solar cells with a power conversion efficiency (PCE) of 19.3% and a perovskite module (4 cm2) with an aperture PCE of 16.4%, using the Cs/FA double cation perovskite made with 10 mol% CsI and 15 mol% FABr (Cs0.1FA0.9PbI2.865Br0.135) are achieved. The Cs/FA double cation perovskites show negligible degradation after annealing at 85 °C for 336 h, outperforming the perovskite materials containing methylammonium (MA).A modified two-step interdiffusion method is developed to fabricate high-quality cesium/formamidinium double cation perovskites with various compositions that have superior intrinsic thermal stability than those with methylammonium cation. Perovskite solar cells and modules based on Cs0.1FA0.9PbI2.865Br0.135 show the highest power conversion efficiency of 19.3% and 16.4%, respectively, in a planar structure.
      PubDate: 2017-05-22T07:20:33.106724-05:
      DOI: 10.1002/adfm.201700920
       
  • Covalently Adaptable Elastin-Like Protein–Hyaluronic Acid (ELP–HA)
           Hybrid Hydrogels with Secondary Thermoresponsive Crosslinking for
           Injectable Stem Cell Delivery
    • Authors: Huiyuan Wang; Danqing Zhu, Alexandra Paul, Lei Cai, Annika Enejder, Fan Yang, Sarah C. Heilshorn
      Abstract: Shear-thinning, self-healing hydrogels are promising vehicles for therapeutic cargo delivery due to their ability to be injected using minimally invasive surgical procedures. An injectable hydrogel using a novel combination of dynamic covalent crosslinking with thermoresponsive engineered proteins is presented. Ex situ at room temperature, rapid gelation occurs through dynamic covalent hydrazone bonds by simply mixing two components: hydrazine-modified elastin-like protein (ELP) and aldehyde-modified hyaluronic acid. This hydrogel provides significant mechanical protection to encapsulated human mesenchymal stem cells during syringe needle injection and rapidly recovers after injection to retain the cells homogeneously within a 3D environment. In situ, the ELP undergoes a thermal phase transition, as confirmed by coherent anti-Stokes Raman scattering microscopy observation of dense ELP thermal aggregates. The formation of the secondary network reinforces the hydrogel and results in a tenfold slower erosion rate compared to a control hydrogel without secondary thermal crosslinking. This improved structural integrity enables cell culture for three weeks postinjection, and encapsulated cells maintain their ability to differentiate into multiple lineages, including chondrogenic, adipogenic, and osteogenic cell types. Together, these data demonstrate the promising potential of ELP–HA hydrogels for injectable stem cell transplantation and tissue regeneration.Shear-thinning and self-healing hydrogels containing protein-engineered elastin-like protein and hyaluronic acid are fabricated through dynamic covalent crosslinking, followed by thermoresponsive physical crosslinking for reinforcement and enhanced stability. These hydrogels have highly tunable stiffness, provide delivered stem cells significant mechanical protection, and maintain the cells after delivery in a 3D environment that supports further differentiation.
      PubDate: 2017-05-19T02:35:36.765922-05:
      DOI: 10.1002/adfm.201605609
       
  • Function Follows Form: Correlation between the Growth and Local Emission
           of Perovskite Structures and the Performance of Solar Cells
    • Authors: M. Ibrahim Dar; Alexander Hinderhofer, Gwenole Jacopin, Valentina Belova, Neha Arora, Shaik Mohammed Zakeeruddin, Frank Schreiber, Michael Grätzel
      Abstract: Understanding the relationship between the growth and local emission of hybrid perovskite structures and the performance of the devices based on them demands attention. This study investigates the local structural and emission features of CH3NH3PbI3, CH3NH3PbBr3, and CH(NH2)2PbBr3 perovskite films deposited under different yet optimized conditions using X-ray scattering and cathodoluminescence spectroscopy, respectively. X-ray scattering shows that a CH3NH3PbI3 film involving spin coating of CH3NH3I instead of dipping is composed of perovskite structures exhibiting a preferred orientation with [202] direction perpendicular to the surface plane. The device based on the CH3NH3PbI3 film composed of oriented crystals yields a relatively higher photovoltage. In the case of CH3NH3PbBr3, while the crystallinity decreases when the HBr solution is used in a single-step method, the photovoltage enhancement from 1.1 to 1.46 V seems largely stemming from the morphological improvements, i.e., a better connection between the crystallites due to a higher nucleation density. Furthermore, a high photovoltage of 1.47 V obtained from CH(NH2)2PbBr3 devices could be attributed to the formation of perovskite films displaying uniform cathodoluminescence emission. The comparative analysis of the local structural, morphological, and emission characteristics of the different perovskite films supports the higher photovoltage yielded by the relatively better performing devices.A comparative analysis of the local structural, morphological, and emission characteristics of different perovskite films rationally justifies the higher photovoltage yielded by the better performing devices.
      PubDate: 2017-05-16T06:11:18.217169-05:
      DOI: 10.1002/adfm.201701433
       
  • General Formation of Monodisperse IrM (M = Ni, Co, Fe) Bimetallic
           Nanoclusters as Bifunctional Electrocatalysts for Acidic Overall Water
           Splitting
    • Authors: Yecan Pi; Qi Shao, Pengtang Wang, Jun Guo, Xiaoqing Huang
      Abstract: The development of bifunctional electrocatalysts for overall water splitting in acidic media is vital for polymer electrolyte membrane (PEM) electrolyzers, but still full of obstacles. Here, highly efficient acidic overall water splitting is realized by utilizing ultrasmall, monodispersed Iridium (Ir)-based nanoclusters (NCs) as the candidate, via a surfactant-free, wet-chemical, and large-scalable strategy. Benefiting from the high specific surface area, clean surface, and strong binding between NCs and supports, the IrM NCs exhibit attractive activities and durability for both oxygen evolution reaction and hydrogen evolution reaction in acidic electrolytes, with IrNi NCs showing the best performance. More significantly, in the overall water splitting, IrNi NCs reach 10 mA cm−2 at a cell voltage of only 1.58 V in 0.5 m H2SO4 electrolyte, holding promises for potential implementation of PEM water electrolysis. This work opens a new avenue toward designing bifunctional “acidic stable” catalysts for efficient overall water splitting.Ir-based nanoclusters (NCs) with highly dispersive feature are synthesized using a wet-chemical large-scalable strategy. Benefiting from the clean surface, high surface-to-volume ratio, large proportion of surface atoms, as well as strong interaction with support, this new series of Ir-based NCs exhibit superior activity and enhanced durability as bifunctional electrocatalysts for overall water splitting in acidic electrolyte.
      PubDate: 2017-05-16T06:11:05.5903-05:00
      DOI: 10.1002/adfm.201700886
       
  • Deep-Blue Phosphorescent Ir(III) Complexes with Light-Harvesting
           Functional Moieties for Efficient Blue and White PhOLEDs in
           Solution-Process
    • Authors: Ganguri Sarada; Woosum Cho, Athithan Maheshwaran, Vijaya Gopalan Sree, Ho-Yeol Park, Yeong-Soon Gal, Myungkwan Song, Sung-Ho Jin
      Abstract: The photoluminescence (PL) efficiency of emitters is a key parameter to accomplish high electroluminescent performance in phosphorescent organic light-emitting diodes (PhOLEDs). With the aim of enhancing the PL efficiency, this study designs deep-blue emitting heteroleptic Ir(III) complexes (tBuCN-FIrpic, tBuCN-FIrpic-OXD, and tBuCN-FIrpic-mCP) for solution-processed PhOLEDs by covalently attaching the light-harvesting functional moieties (mCP-Me or OXD-Me) to the control Ir(III) complex, tBuCN-FIrpic. These Ir(III) complexes show similar deep-blue emission peaks around 453, 480 nm (298 K) and 447, 477 nm (77 K) in chloroform. tBuCN-FIrpic-mCP demonstrates higher light-harvesting efficiency (142%) than tBuCN-FIrpic-OXD (112%), relative to that of tBuCN-FIrpic (100%), due to an efficient intramolecular energy transfer from the mCP group to the Ir(III) complex. Accordingly, the monochromatic PhOLEDs of tBuCN-FIrpic-mCP show higher external quantum efficiency (EQE) of 18.2% with one of the best blue coordinates (0.14, 0.18) in solution-processing technology. Additionally, the two-component (deep-blue:yellow-orange), single emitting layer, white PhOLED of tBuCN-FIrpic-mCP shows a maximum EQE of 20.6% and superior color quality (color rendering index (CRI) = 78, Commission Internationale de L'Eclairage (CIE) coordinates of (0.353, 0.352)) compared with the control device containing sky-blue:yellow-orange emitters (CRI = 60, CIE coordinates of (0.293, 0.395)) due to the good spectral coverage by the deep-blue emitter.Highly efficient deep-blue phosphorescent Ir(III) complexes with light-harvesting groups are introduced for blue and white phosphorescent organic light-emitting diodes. Intramolecular energy transfer from a high triplet energy donor (mCP-Me) to the Ir(III) complex (tBuCN-FIrpic) is found to increase the photoluminescence efficiency of tBuCN-FIrpic-mCP. Therefore, tBuCN-FIrpic-mCP shows high external quantum efficiency of 18.2% with intense blue coordinates (0.142, 0.181) in a solution-process.
      PubDate: 2017-05-16T02:05:55.899905-05:
      DOI: 10.1002/adfm.201701002
       
  • Mo2C/CNT: An Efficient Catalyst for Rechargeable Li–CO2 Batteries
    • Authors: Yuyang Hou; Jiazhao Wang, Lili Liu, Yuqing Liu, Shulei Chou, Dongqi Shi, Huakun Liu, Yuping Wu, Weimin Zhang, Jun Chen
      Abstract: The rechargeable Li–CO2 battery is a novel and promising energy storage system with the capability of CO2 capture due to the reversible reaction between lithium ions and carbon dioxide. Carbon materials as the cathode, however, limit both the cycling performance and the energy efficiency of the rechargeable Li–CO2 battery, due to the insulating Li2CO3 formed in the discharge process, which is difficult to decompose in the charge process. Here, a Mo2C/carbon nanotube composite material is developed as the cathode for the rechargeable Li–CO2 battery and can achieve high energy efficiency (77%) and improved cycling performance (40 cycles). A related mechanism is proposed that Mo2C can stabilize the intermediate reduction product of CO2 on discharge, thus preventing the formation of insulating Li2CO3. In contrast to insulating Li2CO3, this amorphous Li2C2O4-Mo2C discharge product can be decomposed below 3.5 V on charge. The introduction of Mo2C provides an effective solution to the problem of low round-trip efficiency in the Li–CO2 battery.In a rechargeable Li–CO2 battery, molybdenum carbide/carbon nanotubes as a cathode can stabilize the intermediate product on discharge, by building a new chemical bond between Mo and O. This amorphous discharge product effectively prevents the formation of crystalline Li2CO3 and thereby reduces the potential plateau on charge and improves the round-trip efficiency of the rechargeable Li–CO2 battery.
      PubDate: 2017-05-16T02:05:51.654232-05:
      DOI: 10.1002/adfm.201700564
       
  • Solution-Processed Nanoporous Organic Semiconductor Thin Films: Toward
           Health and Environmental Monitoring of Volatile Markers
    • Authors: Fengjiao Zhang; Ge Qu, Erfan Mohammadi, Jianguo Mei, Ying Diao
      Abstract: Porous materials are ubiquitous in nature and have found a wide range of applications because of their unique absorption, optical, mechanical, and catalytic properties. Large surface-area-to-volume ratio is deemed a key factor contributing to their catalytic properties. Here, it is shown that introducing tunable nanopores (50–700 nm) to organic semiconductor thin films enhances their reactivity with volatile organic compounds by up to an order of magnitude, while the surface-area-to-volume ratio is almost unchanged. Mechanistic investigations show that nanopores grant direct access to the highly reactive sites otherwise buried in the conductive channel of the transistor. The high reactivity of nanoporous organic field-effect transistors leads to unprecedented ultrasensitive, ultrafast, selective chemical sensing below the 1 ppb level on a hundred millisecond time scale, enabling a wide range of health and environmental applications. Flexible sensor chip for monitoring breath ammonia is further demonstrated; this is a potential biomarker for chronic kidney disease.A generic method to solution process nanoporous thin films with pore sizes tunable from 50 to 700 nm for both the polymer and small molecule is demonstrated. The nanoporous transistors fabricated exhibit highly sensitive detection of volatile markers below 1 ppb on a hundred millisecond time scale. The nanopores function by exposing reactive sites in the conductive channel to the analytes.
      PubDate: 2017-05-02T10:58:18.987395-05:
      DOI: 10.1002/adfm.201701117
       
  • Multifunctional Biomedical Imaging in Physiological and Pathological
           Conditions Using a NIR-II Probe
    • Authors: Kangquan Shou; Chunrong Qu, Yao Sun, Hao Chen, Si Chen, Lei Zhang, Haibo Xu, Xuechuan Hong, Aixi Yu, Zhen Cheng
      Abstract: Compared with imaging in the visible (400–650 nm) and near-infrared window I (NIR-I, 650–900 nm) regions, imaging in near-infrared window II (NIR-II, 1000–1700 nm) is a highly promising in vivo imaging modality with improved resolution and deeper tissue penetration. Here, a small molecule NIR-II dye,5,5′-(1H,5H-benzo[1,2-c:4,5-c′] bis[1,2,5]thiadiazole)-4,8-diyl)bis(N,N-bis(4-(3-((tert-butyldimethylsilyl)oxy)propyl)phenyl) thiophen-2-amine), is successfully encapsulated into phospholipid vesicles to prepare a probe CQS1000. The novel NIR-II probe is studied for in vivo multifunctional biological imaging. The results of this study indicate that the NIR-II vesicle CQS1000 can noninvasively and dynamically visualize and monitor many physiological and pathological conditions of circulatory systems, including lymphatic drainage and routing, angiogenesis of tumor, and vascular deformity such as arterial thrombus formation and ischemia with high spatial and temporal resolution. More importantly, by virtue of the favorable half-life of blood circulation of CQS1000, NIR-II imaging is capable of aiding precise resection of tumor such as osteosarcoma and accelerating the process of lymph node dissection to complete sentinel lymph node biopsy for better decision making during the tumor surgery. Overall, CQS1000 is a highly promising NIR-II probe for multifunctional biomedical imaging in physiological and pathological conditions, surpassing traditional NIR-I imaging modality and pathologic assessments for clinical diagnosis and treatment.Near-infrared (NIR)-II CQS1000 vesicles are shown to allow visualization and monitoring of the circulatory system noninvasively and dynamically, and to aid in accomplishing more precise resection of tumors in addition to acceleratingthe process of sentinel lymph node biopsy for better decision making. Deep tissue penetration ability and desirable chemical and optical properties render NIR-II CQS1000 a promising probe for future clinical applications.
      PubDate: 2017-04-24T07:15:49.831678-05:
      DOI: 10.1002/adfm.201700995
       
  • RhMoS2 Nanocomposite Catalysts with Pt-Like Activity for Hydrogen
           Evolution Reaction
    • Authors: Yafei Cheng; Shunkai Lu, Fan Liao, Liangbin Liu, Yanqing Li, Mingwang Shao
      Abstract: High overpotentials and low efficiency are two main factors that restrict the practical application for MoS2, the most promising candidate for hydrogen evolution catalysis. Here, RhMoS2 nanocomposites, the addition of a small amount of Rh (5.2 wt%), exhibit the superior electrochemical hydrogen evolution performance with low overpotentials, small Tafel slope (24 mV dec−1), and long term of stability. Experimental results reveal that 5.2 wt% RhMoS2 nanocomposite, even exceeding the commercial 20 wt% Pt/C when the potential is less than −0.18 V, exhibits an excellent mass activity of 13.87 A mgmetal−1 at −0.25 V, four times as large as that of the commercial 20 wt% Pt/C catalyst. The hydrogen yield of 5.2 wt% RhMoS2 nanocomposite is 26.3% larger than that of the commercial 20 wt% Pt/C at the potential of −0.25 V. The dramatically improved electrocatalytic performance of RhMoS2 nanocomposites may be attributed to the hydrogen spillover from Rh to MoS2.RhMoS2 nanocomposite (5.2 wt%) exhibits dramatic hydrogen evolution reaction activity with a lower Tafel slope and higher mass activity than those of 20 wt% Pt/C catalysts. This superior electrocatalytic performance may be attributed to the hydrogen spillover from Rh to MoS2.
      PubDate: 2017-04-24T07:15:42.337782-05:
      DOI: 10.1002/adfm.201700359
       
  • MoSe2-Covered N,P-Doped Carbon Nanosheets as a Long-Life and High-Rate
           Anode Material for Sodium-Ion Batteries
    • Authors: Feier Niu; Jing Yang, Nana Wang, Dapeng Zhang, Weiliu Fan, Jian Yang, Yitai Qian
      Abstract: MoSe2 grown on N,P-co-doped carbon nanosheets is synthesized by a solvothermal reaction followed with a high-temperature calcination. This composite has an interlayer spacing of MoSe2 expanded to facilitate sodium-ion diffusion, MoSe2 immobilized on carbon nanosheets to improve charge-transfer kinetics, and N and P incorporated into carbon to enhance its interaction with active species upon cycling. These features greatly improve the electrochemical performance of this composite, as compared to all the controls. It presents a specific capacity of 378 mAh g−1 after 1000 cycles at 0.5 A g−1, corresponding to 87% of the capacity at the second cycle. Ex situ Raman spectra and high-resolution transmission electron microscopy images confirm that it is element Se, rather than MoSe2, formed after the charging process. The interaction of the active species with modified carbon is simulated using density functional theory to explain this excellent stability. The superior rate capability, where the capacity at 15 A g−1 equals ≈55% of that at 0.5 A g−1, could be associated with the significant contribution of pseudocapacitance. By pairing with homemade Na3V2(PO4)3/C, this composite also exhibits excellent performances in full cells.MoSe2 grown on N,P-co-doped carbon nanosheets exhibits long cycle life and high rate performance in sodium-ion batteries. These features are attributed to the strong binding affinity of N,P-co-doped carbon, the pseudocapacitive nature, and the unique 3D network.
      PubDate: 2017-04-21T01:26:07.441245-05:
      DOI: 10.1002/adfm.201700522
       
  • Healable Transparent Electronic Devices
    • Authors: Crystal Shaojuan Luo; Pengbo Wan, Hui Yang, Sayyed Asim Ali Shah, Xiaodong Chen
      Abstract: With the advent of the digital era, healable electronic devices are being developed to alleviate the propagation of breakdown in electronics due to the mechanical damage caused by bending, accidental cutting or scratching. Meanwhile, flexible transparent electronics, exhibiting high transmittance and robust flexibility, are drawing enormous research efforts due to their potential applications in various integrated wearable electronics. However, the breakdown of flexible transparent electronics seriously limits their reliability and lifetime. Therefore, transparent healable electronics are desired to tackle these problems, yet most of the healable electronics are not transparent nowadays. The combination of high performance, healability, and transparency into electronics is often mutually exclusive. Herein, after a brief introduction of self-healing materials, healable electronics, and flexible transparent electronics, the recent progress in the healable electronic devices without transparency is reviewed in detail. Then, healable transparent electronic devices with high transparency, robust portability, and reliable flexibility are summarized. They are drawing great attention owing to their potential application in optical devices as well as smart wearable and integrated optoelectronic devices. Following that, the critical challenges and prospects are highlighted for the development of healable transparent electronic devices.Healable transparent electronic devices (HTEDs) with high transparency, robust portability, and reliable healability exhibit potential applications in optical devices as well as smart, wearable, and integrated optoelectronics. The emerging advances of HTEDs are intensively described. The critical challenges and prospects are provided for developing HTEDs to fulfill the future demands of high performance and integrated optoelectronic devices with multiple functions and superior healability.
      PubDate: 2017-04-19T01:37:56.396474-05:
      DOI: 10.1002/adfm.201606339
       
  • Intelligent Molecular Searcher from Logic Computing Network Based on
           Eu(III) Functionalized UMOFs for Environmental Monitoring
    • Authors: Xiao-Yu Xu; Bing Yan
      Abstract: By taking advantage of facile preparation and sensitive recognition capacity, the first example of a fluorescence system based on Eu(III) functionalized UiO(bpdc) (UMOFs) has been constructed for effective combination of ions recognition and logic computing. All the ions, including Hg2+, Ag+, and S2− in the system are water harmful, which can be recognized through affecting energy transfer or framework structure. By the self-assembling, competing and connecting with each other, Eu(III)@UMOFs and the ions have achieved the implementation of Boolean logic network system connecting the elementary logic operations (NOR, INH, and IMP) and integrative logic operation (OR + INH), also obtaining computing keypad-lock security system by sequential logic operation. To deal with uncertain information in the analog region of nonlinear response (fluorescence and concentration), soft computation through the formulation of fuzzy logic operation has been constructed. On the basis of Boolean logic and fuzzy logic, one intelligent molecular searcher can be realized by taking chemical events (Hg2+, Ag+, and S2−) as programmable words and chemical interactions as syntax. Considering the particularity of all the input ions, the approach is helpful in developing the advanced logic program based on Eu(III)@UMOFs for application in environmental monitoring.By combining ion recognition and logic computing (Boolean and fuzzy), an intelligent molecular searcher for polluting ions (Hg2+, Ag+, and S2−) in water has been constructed based on fluorescence Eu(III) functionalized UiO(bpdc) system and the molecular searcher is helpful in developing the advanced logic program for application in environmental monitoring.
      PubDate: 2017-04-18T06:41:03.479759-05:
      DOI: 10.1002/adfm.201700247
       
  • Solution-Growth Strategy for Large-Scale “CuGaO2 Nanoplate/ZnS
           Microsphere” Heterostructure Arrays with Enhanced UV Adsorption and
           Optoelectronic Properties
    • Authors: Yanmei Li; Yun Song, Yingchang Jiang, Mingxiang Hu, Zhichang Pan, Xiaojie Xu, Hongyu Chen, Yuesheng Li, Linfeng Hu, Xiaosheng Fang
      Abstract: Intrinsically p-type conductivity and a wide bandgap of ≈3.6 V endow inorganic delafossite CuGaO2 with great promise for fabricating high-performance UV photodetectors. Nevertheless, CuGaO2-based optoelectronic devices hindered because the intrinsic direct transitions are symmetry forbidden in CuGaO2. This study reports a large-area synthesis of “CuGaO2 nanoplate/ZnS microsphere” heterostructure arrays using a facile solution-based strategy associated with an oil/water interfacial self-assembly approach. It is found that a large number of ZnS microspheres with a polycrystalline structure grow on the top surface of CuGaO2 hexagonal platelets through Ostwald ripening mechanism, forming high-density p–n heterojunctions. A parabolic dependence between the size of ZnS microsphere and the growth time is confirmed in this growth. The UV light adsorption of the heterostructure CuGaO2/ZnS thin film is two times higher than that of the pristine CuGaO2 thin film. Furthermore, the as-designed “CuGaO2 nanoplate/ZnS microsphere” heterostructure arrays exhibit enhanced photoresponse properties. This work offers a new insight into the rational design of optoelectronic devices from the synergetic effect of p-type 2D nanoplates as well as n-type nanostructures such as ZnS, ZnO, CdS, and CdO.Large-area “CuGaO2 nanoplate/ZnS microsphere” p–n heterojunction arrays are successfully grown using a facile low-temperature solution strategy associated with an oil/water interfacial self-assembly approach. Such a heterostructured structure shows much higher UV-light adsorption and superior optoelectronic performance due to the synergetic effects between the CuGaO2 nanoplate and the ZnS microsphere.
      PubDate: 2017-04-18T02:51:19.738029-05:
      DOI: 10.1002/adfm.201701066
       
  • Solvothermal Synthesis of High-Quality All-Inorganic Cesium Lead Halide
           Perovskite Nanocrystals: From Nanocube to Ultrathin Nanowire
    • Authors: Min Chen; Yatao Zou, Linzhong Wu, Qi Pan, Di Yang, Huicheng Hu, Yeshu Tan, Qixuan Zhong, Yong Xu, Haiyu Liu, Baoquan Sun, Qiao Zhang
      Abstract: Recently, all-inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals have drawn much attention because of their outstanding photophysical properties and potential applications. In this work, a simple and efficient solvothermal approach to prepare CsPbX3 nanocrystals with tunable and bright photoluminescent (PL) properties, controllable composition, and morphology is presented. CsPbX3 nanocubes are successfully prepared with bright emission high PL quantum yield up to 80% covering the full visible range and narrow emission line widths (from 12 to 36 nm). More importantly, ultrathin CsPbX3 (X = Cl/Br, Br, and Br/I) nanowires (with diameter as small as ≈2.6 nm) can be prepared in a very high morphological yield (almost 100%). A strong quantum confinement effect is observed in the ultrathin nanowires, in which both the absorption and emission peaks shift to shorter wavelength range compared to their bulk bandgap. The reaction parameters, such as temperature and precursors, are varied to investigate the growth process. A white light-emitting device prototype device with wide color gamut covering up to 120% of the National Television System Committee standard has been demonstrated by using CsPbBr3 nanocrystals as the green light source. The method in this study provides a simple and efficient way to prepare high-quality CsPbX3 nanocrystals.A solvothermal method is developed to prepare high-quality all-inorganic cesium lead halide (CsPbX3) nanocrystals. Monodisperse CsPbX3 nanocubes and ultrathin CsPbX3 nanowires are prepared. By using the prepared CsPbBr3 nanocrystals as the green light source, a white light-emitting prototype device with wide color gamut covering up to 120% of the National Television System Committee standard is fabricated.
      PubDate: 2017-04-18T02:51:13.440987-05:
      DOI: 10.1002/adfm.201701121
       
  • Organic Nanoprobe Cocktails for Multilocal and Multicolor Fluorescence
           Imaging of Reactive Oxygen Species
    • Authors: Chao Yin; Houjuan Zhu, Chen Xie, Lei Zhang, Peng Chen, Quli Fan, Wei Huang, Kanyi Pu
      Abstract: Hypochlorite (ClO−) as a highly reactive oxygen species not only acts as a powerful “guarder” in innate host defense but also regulates inflammation-related pathological conditions. Despite the availability of fluorescence probes for detection of ClO− in cells, most of them can only detect ClO− in single cellular organelle, limiting the capability to fully elucidate the synergistic effect of different organelles on the generation of ClO−. This study proposes a nanoprobe cocktail approach for multicolor and multiorganelle imaging of ClO− in cells. Two semiconducting oligomers with different π-conjugation length are synthesized, both of which contain phenothiazine to specifically react with ClO− but show different fluorescent color responses. These sensing components are self-assembled into the nanoprobes with the ability to target cellular lysosome and mitochondria, respectively. The mixture of these nanoprobes forms a nano-cocktail that allows for simultaneous imaging of elevated level of ClO− in lysosome and mitochondria according to fluorescence color variations under selective excitation of each nanoprobe. Thus, this study provides a general concept to design probe cocktails for multilocal and multicolor imaging.Organic nanoprobe cocktails are developed based on two semiconducting oligomers with different fluorescence color responses to ClO−. The nano-cocktails allow for simultaneous and differential multicolor imaging of elevated levels of ClO− in cellular lysosome and mitochondria.
      PubDate: 2017-04-11T07:07:27.946911-05:
      DOI: 10.1002/adfm.201700493
       
  • Regulating Top-Surface Multilayer/Single-Crystal Graphene Growth by
           “Gettering” Carbon Diffusion at Backside of the Copper Foil
    • Authors: Irfan H. Abidi; Yuanyue Liu, Jie Pan, Abhishek Tyagi, Minghao Zhuang, Qicheng Zhang, Aldrine A. Cagang, Lu-Tao Weng, Ping Sheng, William A. Goddard, Zhengtang Luo
      Abstract: A unique strategy is reported to constrain the nucleation centers for multilayer graphene (MLG) and, later, single-crystal graphene domains by gettering carbon source on backside of the flat Cu foil, during chemical vapor deposition. Hitherto, for a flat Cu foil, the top-surface-based growth mechanism is emphasized, while overlooking the graphene on the backside. However, the systematic experimental findings indicate a strong correlation between the backside graphene and the nucleation centers on the top-surface, governed by the carbon diffusion through the bulk Cu. This understanding steers to devise a strategy to mitigate the carbon diffusion to the top-surface by using a carbon “getter” substrate, such as nickel, on the backside of the Cu foil. Depth profiling of the nickel substrate, along with the density functional theory calculations, verifies the gettering role of the nickel support. The implementation of the backside carbon gettering approach on single-crystal graphene growth results in lowering the nucleation density by two orders of magnitude. This enables the single-crystal domains to grow by 6 mm laterally on the untreated Cu foil. Finally, the growth of large-area polycrystalline single layer graphene, free of unwanted MLG domains, with significantly improved field-effect mobility of ≈6800 cm2 V−1 s−1 is demonstrated.A backside carbon gettering approach is implemented to manipulate top-surface CVD graphene growth on Cu foil using a Ni support substrate. This strategy limits the nucleation centers for multilayer and single-crystal graphene domains at the top-surface through gettering the carbon source at backside of the Cu foil, resulting in high quality uniform single-crystal graphene.
      PubDate: 2017-04-11T06:26:43.334131-05:
      DOI: 10.1002/adfm.201700121
       
  • Highly Hydrophobic ZIF-8/Carbon Nitride Foam with Hierarchical Porosity
           for Oil Capture and Chemical Fixation of CO2
    • Authors: Daeok Kim; Dae Woo Kim, Onur Buyukcakir, Min-Kyeong Kim, Kyriaki Polychronopoulou, Ali Coskun
      Abstract: The introduction of hierarchical porosity into metal-organic frameworks (MOFs) has been of considerable interest in gas separation and heterogeneous catalysis due to the efficient mass transfer kinetics through meso/macropores. Here, a facile, scalable approach is reported for the preparation of carbon nitride (CN) foams as structural templates with micrometer-sized pores and high nitrogen content of 25.6 wt% by the fast carbonization of low-cost melamine foam. The nitrogen functionalities of CN foam facilitate chemical anchoring and growth of ZIF-8 (zeolitic imidazolate frameworks) crystals, which leads to the development of hierarchical porosity. The growth of ZIF-8 crystals also renders CN foam, which is hydrophilic in nature, highly hydrophobic exhibiting 135° of water contact angle due to the enhanced surface roughness, thus creating a natural shield for the MOF crystals against water. The introduction of ZIF-8 crystals onto the CN foam enables selective absorption of oils up to 58 wt% from water/oil mixtures and also facilitates the highly efficient conversion of CO2 to chloropropene carbonate in a quantitative yield with excellent product selectivity. Importantly, this present approach could be extended to the vast number of MOF structures, including the ones suffering from water instability, for the preparation of highly functional materials for various applications.A facile, scalable carbonization strategy is introduced for the preparation of carbon nitride foams with high nitrogen contents and micrometer-sized pores as a structural template for the growth of ZIF-8 crystals. This renders the resulting frameworks highly hydrophobic such that they can be used to clean up oil spills from water and are catalytically active for CO2 conversion.
      PubDate: 2017-04-11T01:40:41.656325-05:
      DOI: 10.1002/adfm.201700706
       
  • Hierarchically Targeted and Penetrated Delivery of Drugs to Tumors by
           
    • Authors: Yu-Lin Su; Ting-Wei Yu, Wen-Hsuan Chiang, Hsin-Cheng Chiu, Chun-Hsiang Chang, Chi-Shiun Chiang, Shang-Hsiu Hu
      Abstract: Theranostic nanohybrids are promising for effective delivery of therapeutic drug or energy and for imaging-guided therapy of tumors, which is demanded in personalized medicine. Here, a size-changeable graphene quantum dot (GQD) nanoaircraft (SCNA) that serves as a hierarchical tumor-targeting agent with high cargo payload is developed to penetrate and deliver anticancer drug into deep tumors. The nanoaircraft is composed of ultrasmall GQDs (less than 5 nm) functionalized with a pH-sensitive polymer that demonstrates an aggregation transition at weak acidity of tumor environment but is stable at physiological pH with stealth function. A size conversion of the SCNA at the tumor site is further actuated by near-infrared irradiation, which disassembles 150 nm of SCNA into 5 nm of doxorubicin (DOX)/GQD like a bomb-loaded jet, facilitating the penetration into the deep tumor tissue. At the tumor, the penetrated DOX/GQD can infect neighboring cancer cells for repeated cell killing. Such a SCNA integrated with combinational therapy successfully suppresses xenograft tumors in 18 d without distal harm. The sophisticated strategy displays the hierarchically targeted and penetrated delivery of drugs and energy to deep tumor and shows potential for use in other tumor therapy.Size-changeable nanoaircrafts carrying graphene quantum dots (GQDs) loaded with the anticancer drug doxorubicin (DOX) can achieve penetrating drug delivery hierarchically, on demand, and in vivo. pH-sensitive enhanced aggregation and photopenetrating thermal-chemotherapy allow a shuriken-like penetration of DOX/GQDs, which also improves homogeneous treatment in the tumor via hyperthermia and ultrasmall GQDs, all contributing to the killing of cells.
      PubDate: 2017-04-11T01:36:08.174638-05:
      DOI: 10.1002/adfm.201700056
       
  • Hollow Nanostars with Photothermal Gold Caps and Their Controlled Surface
           Functionalization for Complementary Therapies
    • Authors: Ranran Wang; Nana Zhao, Fu-Jian Xu
      Abstract: Gold nanoparticles exhibiting absorption in the desirable near-infrared region are attractive candidates for photothermal therapy (PTT). Furthermore, the construction of one nanoplatform employing gold nanoparticles for complementary therapy is still a great challenge. Here, well-defined unique hollow silica nanostars with encapsulated gold caps (starlike Au@SiO2) are readily synthesized using a sacrificial template method. Ethanolamine-functionalized poly(glycidyl methacrylate) (denoted as BUCT-PGEA) brushes are then grafted controllably from the surface of starlike Au@SiO2 nanoparticles via surface-initiated atom transfer radical polymerization to produce starlike Au@SiO2-PGEA. The photothermal effect of gold caps with a cross cavity can be utilized for PTT. The interior hollow feature of starlike Au@SiO2 nanoparticles endows them with excellent drug loading capability for chemotherapy, while the polycationic BUCT-PGEA brushes on the surface provide good transfection performances for gene therapy, which will overcome the penetration depth limitation of PTT for tumor therapy. Compared with ordinary spherical Au@SiO2-PGEA counterparts, the starlike Au@SiO2-PGEA hybrids with sharp horns favor endocytosis, which can contribute to enhanced antitumor effectiveness. The rational integration of photothermal gold caps, hollow nanostars, and polycations through the facile strategy might offer a promising avenue for complementary cancer therapy.Nanohybrids of hollow nanostars with encapsulated gold caps with unique photothermal characteristic are readily synthesized for complementary photothermal therapy, gene therapy, and chemotherapy.
      PubDate: 2017-04-10T08:26:26.689997-05:
      DOI: 10.1002/adfm.201700256
       
  • One-Pot Synthesis of Dealloyed AuNi Nanodendrite as a Bifunctional
           Electrocatalyst for Oxygen Reduction and Borohydride Oxidation Reaction
    • Authors: Jiali Wang; Fuyi Chen, Yachao Jin, Yimin Lei, Roy L. Johnston
      Abstract: A novel one-pot approach for synthesizing the dealloyed nanomaterials at room temperature is introduced for the first time. In such a synthetic strategy, applying modulated potentials effectively simplifies the traditional dealloying route, which usually requires additional corrosion process to dissolve nonprecious metals. The dealloyed AuNi nanodendrites (AuNi NDs) with tunable composition and uniformly elemental distribution are well developed by the one-pot strategy. Impressively, the as-synthesized AuNi NDs exhibit a higher electrochemically active area and definite improvements in electrocatalytic activity for oxygen reduction reaction (ORR) and borohydride oxidation reaction (BOR) compared to the commercial Pt/C. In particular, the AuNi NDs are 81 mV more positive in half-wave potential and about 3.1 times higher in specific activity (at 0.85 V) for the ORR than Pt/C, together with excellent stability and methanol tolerance. The superior BOR activity is highly promising compared to the previously reported catalysts. The unique nanodendritic structure with Au-rich surface and bimetallic electronic effect is the main factor to greatly enhance the bifunctional catalytic performance for the AuNi NDs. Furthermore, such a newly developed facile method is of great significance because it is one of the first examples to effectively engineer dealloyed bimetallic nanostructures via the practical and low-cost route for electrocatalytic applications.The first example of one-pot synthesis of dealloyed bimetallic nanostructures is proposed in which alloying and dealloying processes are precisely controlled by applying modulated potentials in the single electrolyte. The unique nanodendritic structure and tuned electronic effect enable the as-synthesized AuNi nanodendrites to possess superior bifunctional catalytic performance for oxygen reduction and borohydride oxidation compared to the commercial state-of-the-art Pt/C.
      PubDate: 2017-04-10T08:26:05.813889-05:
      DOI: 10.1002/adfm.201700260
       
 
 
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