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21.
Hybrid Fibers Made of Molybdenum Disulfide,Reduced Graphene Oxide,and Multi‐Walled Carbon Nanotubes for Solid‐State,Flexible, Asymmetric Supercapacitors 下载免费PDF全文
Dr. Gengzhi Sun Xiao Zhang Rongzhou Lin Jian Yang Prof. Hua Zhang Prof. Peng Chen 《Angewandte Chemie (International ed. in English)》2015,54(15):4651-4656
One of challenges existing in fiber‐based supercapacitors is how to achieve high energy density without compromising their rate stability. Owing to their unique physical, electronic, and electrochemical properties, two‐dimensional (2D) nanomaterials, e.g., molybdenum disulfide (MoS2) and graphene, have attracted increasing research interest and been utilized as electrode materials in energy‐related applications. Herein, by incorporating MoS2 and reduced graphene oxide (rGO) nanosheets into a well‐aligned multi‐walled carbon nanotube (MWCNT) sheet followed by twisting, MoS2‐rGO/MWCNT and rGO/MWCNT fibers are fabricated, which can be used as the anode and cathode, respectively, for solid‐state, flexible, asymmetric supercapacitors. This fiber‐based asymmetric supercapacitor can operate in a wide potential window of 1.4 V with high Coulombic efficiency, good rate and cycling stability, and improved energy density. 相似文献
22.
Sunlight‐Driven Formation and Dissociation of a Dynamic Mixed‐Valence Thallium(III)/Thallium(I) Porphyrin Complex 下载免费PDF全文
Victoria Ndoyom Luca Fusaro Vincent Dorcet Bernard Boitrel Stéphane Le Gac 《Angewandte Chemie (International ed. in English)》2015,54(12):3806-3811
Inspired by a Newton’s cradle device and interested in the development of redox‐controllable bimetallic molecular switches, a mixed‐valence thallium(III)/thallium(I) bis‐strap porphyrin complex, with TlIII bound out of the plane of the N core and TlI hung to a strap on the opposite side, was formed by the addition of TlOAc to the free base and exposure to indirect sunlight. In this process, oxygen photosensitization by the porphyrin allows the oxidation of TlI to TlIII. The bimetallic complex is dynamic as the metals exchange their positions symmetrically to the porphyrin plane with TlIII funneling through the macrocycle. Further exposure of the complex to direct sunlight leads to thallium dissociation and to total recovery of the free base. Hence, the porphyrin plays a key role at all stages of the cycle of the complex: It hosts two metal ions, and by absorbing light, it allows the formation and dissociation of TlIII. These results constitute the basis for the further design of innovative light‐driven bimetallic molecular devices. 相似文献
23.
Inside Back Cover: A Multifunctional Bimetallic Molecular Device for Ultrasensitive Detection,Naked‐Eye Recognition,and Elimination of Cyanide Ions (Chem. Eur. J. 37/2015) 下载免费PDF全文
24.
A Facile and Universal Top‐Down Method for Preparation of Monodisperse Transition‐Metal Dichalcogenide Nanodots 下载免费PDF全文
Xiao Zhang Zhuangchai Lai Zhengdong Liu Chaoliang Tan Ying Huang Dr. Bing Li Dr. Meiting Zhao Prof. Linghai Xie Prof. Wei Huang Prof. Hua Zhang 《Angewandte Chemie (International ed. in English)》2015,54(18):5425-5428
Despite unique properties of layered transition‐metal dichalcogenide (TMD) nanosheets, there is still lack of a facile and general strategy for the preparation of TMD nanodots (NDs). Reported herein is the preparation of a series of TMD NDs, including TMD quantum dots (e.g. MoS2, WS2, ReS2, TaS2, MoSe2 and WSe2) and NbSe2 NDs, from their bulk crystals by using a combination of grinding and sonication techniques. These NDs could be easily separated from the N‐methyl‐2‐pyrrolidone when post‐treated with n‐hexane and then chloroform. All the TMD NDs with sizes of less than 10 nm show a narrow size distribution with high dispersity in solution. As a proof‐of‐concept application, memory devices using TMD NDs, for example, MoSe2, WS2, or NbSe2, mixed with polyvinylpyrrolidone as active layers, have been fabricated, which exhibit a nonvolatile write‐once‐read‐many behavior. These high‐quality TMD NDs should have various applications in optoelectronics, solar cells, catalysis, and biomedicine. 相似文献
25.
Hyperbranched Hybridization Chain Reaction for Triggered Signal Amplification and Concatenated Logic Circuits 下载免费PDF全文
Dr. Sai Bi Min Chen Xiaoqiang Jia Ying Dong Prof. Dr. Zonghua Wang 《Angewandte Chemie (International ed. in English)》2015,54(28):8144-8148
A hyper‐branched hybridization chain reaction (HB‐HCR) is presented herein, which consists of only six species that can metastably coexist until the introduction of an initiator DNA to trigger a cascade of hybridization events, leading to the self‐sustained assembly of hyper‐branched and nicked double‐stranded DNA structures. The system can readily achieve ultrasensitive detection of target DNA. Moreover, the HB‐HCR principle is successfully applied to construct three‐input concatenated logic circuits with excellent specificity and extended to design a security‐mimicking keypad lock system. Significantly, the HB‐HCR‐based keypad lock can alarm immediately if the “password” is incorrect. Overall, the proposed HB‐HCR with high amplification efficiency is simple, homogeneous, fast, robust, and low‐cost, and holds great promise in the development of biosensing, in the programmable assembly of DNA architectures, and in molecular logic operations. 相似文献
26.
Luis Fermín Capitán-Vallvey Nuria López-Ruiz Antonio Martínez-Olmos Miguel M. Erenas Alberto J. Palma 《Analytica chimica acta》2015
Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed. 相似文献
27.
Prof. Giuseppe Alibrandi Prof. Luigi Fabbrizzi Prof. Maurizio Licchelli Dr. Antonio Puglisi 《Chemphyschem》2015,16(1):85-89
This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH‐sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH–t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di‐copper(II) bistren complex in a single run, in a completely automatic experiment. 相似文献
28.
Altering the Position of Phenyl Substitution to Adjust Film Morphology and Memory Device Performance 下载免费PDF全文
Qianhao Zhou Rongcheng Bo Dr. Jinghui He Hao Zhuang Dr. Hua Li Dr. Najun Li Dr. Dongyun Chen Prof. Qingfeng Xu Prof. Jianmei Lu 《化学:亚洲杂志》2015,10(7):1474-1479
In this study, two structural isomers α‐PBT and β‐PBT, which only differ in the phenyl substituent position on the quinoline chromophore, have been designed and successfully synthesized. The influences of substituent position on the film morphology and the storage performance of the devices were investigated. Both molecules employed in the memory devices exhibited same nonvolatile binary (write‐once‐read‐many‐times; WORM) characteristics, but the switch threshold voltage (Vth) of the β‐PBT‐based device was clearly lower than that of the α‐PBT‐based device. Simulation results demonstrate that the variation of the phenyl substituent position led to different intermolecular stacking styles and thus to varied grain sizes for each film morphology. This work illustrates that altering the phenyl substituent position on the molecular backbone could improve the quality of the film morphology and reduce power consumption, which is good for the rational design of future advanced organic memory devices (OMDs). 相似文献
29.
Young‐Inn Kim Young‐Kwang Song Daeyoung Kim Sung Kwon Kang 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(10):908-911
Metal complexes with Schiff base ligands have been suggested as potential phosphors in electroluminescent devices. In the title complex, tetrakis[6‐methyl‐2‐({[(pyridin‐2‐yl)methyl]imino}methyl)phenolato‐1:2κ8N,N′,O:O;3:2κ8N,N′,O:O]trizinc(II) hexafluoridophosphate methanol monosolvate, [Zn3(C14H13N2O)4](PF6)2·CH3OH, the ZnII cations adopt both six‐ and four‐coordinate geometries involving the N and O atoms of tetradentate 6‐methyl‐2‐({[(pyridin‐2‐yl)methyl]imino}methyl)phenolate ligands. Two terminal ZnII cations adopt distorted octahedral geometries and the central ZnII cation adopts a distorted tetrahedral geometry. The O atoms of the phenolate ligands bridge three ZnII cations, forming a dicationic trinuclear metal cluster. The title complex exhibits a strong emission at 469 nm with a quantum yield of 15.5%. 相似文献
30.
Valentina Bleve Christian Schäfer Dr. Paola Franchi Dr. Serena Silvi Prof. Dr. Elisabetta Mezzina Prof. Dr. Alberto Credi Prof. Marco Lucarini 《ChemistryOpen》2015,4(1):2-21
An acid–base switchable molecular shuttle based on a [2]rotaxane, incorporating stable radical units in both the ring and dumbbell components, is reported. The [2]rotaxane comprises a dibenzo[24]crown-8 ring (DB24C8) interlocked with a dumbbell component that possesses a dialkylammonium (NH2+) and a 4,4′-bipyridinium (BPY2+) recognition site. Deprotonation of the rotaxane NH2+ centers effects a quantitative displacement of the DB24C8 macroring to the BPY2+ recognition site, a process that can be reversed by acid treatment. Interaction between stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals connected to the ring and dumbbell components could be switched between noncoupled (three-line electron paramagnetic resonance (EPR) spectrum) and coupled (five-line EPR spectrum) upon displacement of the spin-labelled DB24C8 macroring. The complete base- and acid-induced switching cycle of the EPR pattern was repeated six times without an appreciable loss of signal, highlighting the reversibility of the process. Hence, this molecular machine is capable of switching on/off magnetic interactions by chemically driven reversible mechanical effects. A system of this kind represents an initial step towards a new generation of nanoscale magnetic switches that may be of interest for a variety of applications. 相似文献