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61.
Improve on/off ratio of organic heterojunction transistors by adopting single-sandwich configuration
Jianwu Shi Hua Wang Haibo Wang Hongkun Tian Yanhou Geng Donghang Yan 《Solid-state electronics》2011,61(1):65-68
Organic heterojunction transistors (OHJTs) based on 5,5′″-bis(naphtha-2-yl)-2,2′:5″,2′″-quaterthiophene (NaT4)/copper-hexadecafluoro-phthalocyanine (F16CuPc) heterojunction were fabricated in single-sandwich and sandwich configurations, respectively. All the devices operated in depletion-accumulation (normally-on) mode. High field-effect mobility of 0.35 cm2/Vs was obtained for all devices, which was higher than that, 0.20 cm2/Vs of the devices with NaT4 as active layer. The on/off ratio of 1 × 105 was obtained for OHJTs with single-sandwich configuration, which is three orders of magnitude higher than that of OHJTs with sandwich configuration. Compared with OHJTs with sandwich configuration, the higher on/off ratio was mainly determined by the lower off state current in OHJTs with single-sandwich configuration. In OHJTs with single-sandwich configuration, the well-type shield effect of the source and drain electrodes caused a very narrow empty region in F16CuPc film, which is responsible for the lower off state current. 相似文献
62.
63.
Xiubo Jiang Yi Shi Wen Zhu Yongming Chen Fu Xi 《Journal of polymer science. Part A, Polymer chemistry》2012,50(20):4239-4245
Well‐defined mikto‐topology star polystyrene composed of one cyclic arm and four linear arms was synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu‐catalyzed azide‐alkyne cycloaddition (CuAAC) click reaction. First, the bromine‐alkyne α,ω‐linear polystyrenes containing four hydroxyl groups protected with acetone‐based ketal groups were synthesized by ATRP of styrene using a designed initiator. Then, the bromine end‐group was converted to the azide and the linear polystyrene was cyclized intra‐molecularly by the CuAAC reaction. The four hydroxyl groups were released by deprotection and then esterified with 2‐bromoisobutyryl bromide to produce a cyclic polymer bearing four ATRP initiating units. By subsequent ATRP of styrene to grow linear polymers with the cyclic polystyrene as a macroinitiator, the mikto‐topology star polymers were prepared. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
64.
Shaoyong Ke Zhigang Zhang Ya-Ni Zhang Liqiao Shi Ronghua Zhou Aibing Jiang Ying Liang Ziwen Yang 《Research on Chemical Intermediates》2012,38(8):1827-1837
A novel series of ether functionalization of spiro-tetronic acid derivatives have been designed and conveniently synthesized via three steps, including esterification, one-pot heterocyclization, and etherification reactions. The target molecules have been identified on the basis of analytical spectra data. All newly synthesized compounds have been screened for their potential insecticidal activity against Heliothis armigera and Plutella xylostella compared with spirodiclofen by standard method. 相似文献
65.
HU Shi & WANG Xun 《中国科学:化学(英文版)》2012,(11):2256-2270
Ultrathin nanostructures have attracted much attention in recent years due to their predictable novel properties and various potential applications. The improvement in synthetic skills has led to many successful syntheses of nanostructures including zerodimensional (0D) nanoclusters, one-dimensional (1D) nanowires, two-dimensional (2D) nanosheets and other higher-level complex nanostructures, where cluster-assembly of primary nanocrystals is a common process. In this review, progress in ultrathin nanocrystals in the last decade and several important factors in the growth mechanisms are covered. By giving examples of cluster assembly from 1D to 3D nanostructures, the utility of cluster assembly in the synthesis of new materials has been demonstrated. 相似文献
66.
67.
In 1994, I. Kan constructed a smooth map on the annulus admitting two physical measures, whose basins are intermingled. In this paper, we prove that Kan's map is robustly topologically mixing. 相似文献
68.
Empirical potential structure refinements have been made to recent high-energy x-ray diffraction data, providing molecular models of deeply supercooled water. The average O-O coordination number is found to drop from 5.13 at 293?K to 4.85 at 244?K, within 3.5?Å. Triplet O-O-O bond angle distributions reveal a broad peak centred at 96.4° at 293?K which shifts to 100.0° at 244?K, indicative of the local geometry becoming increasingly tetrahedral with decreasing temperature. However, although the number of non-bonded interstitial molecules between the first and second shells is depleted upon cooling, the number of interstitial molecules forming triplets that are embedded within the hydrogen bonded tetrahedral network at θOOO?=?53°, remains constant. This is consistent with previous observations of an invariant O-O coordination number with temperature (4.24 out to 3.3?Å) and corresponds to non-bonded molecules positioned at close to half the ideal tetrahedral angle. Both -O-O-O- and hydrogen-bonded -O-H-O- ring length distributions show increases in 6 and 7-membered rings upon supercooling. This is concomitant with a shift and increase in intensity of peaks at r4 ~8.7?Å and r5 ~10.8?Å in the oxygen-oxygen pair distribution function, which in the models correspond to correlations between adjacent and next-nearest-neighbour hydrogen-bonded rings. 相似文献
69.
Xiao-Yi Song Yu-Hang Zhang Ping-Ping Sun Prof. Dr. Jun Gao Prof. Dr. Fa-Nian Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(25):5654-5661
Novel lithium–lanthanide (Ln: cerium and praseodymium) bimetallic coordination polymers with formulas C10H2LnLiO8 (Ln: Ce (CeLipma) and Pr (PrLipma)) and C10H3CeO8 (Cepma) were prepared through a simple hydrothermal method. The three compounds were characterized by means of FTIR spectroscopy, X-ray diffraction, single-crystal X-ray diffraction, SEM, TEM, and X-ray photoelectron spectroscopy. The results of structural refinement show that they belong to triclinic symmetry and P space group with cerium (or praseodymium) and lithium cations, forming coordination bonds to oxygen atoms from different pyromellitic acid molecules, and leading to the construction of 3D structures. It is interesting to note that the frameworks exclude any coordination water and lattice water. As an electrode material for lithium-ion batteries, CeLipma exhibits a maximum capacity of 800.5 mAh g−1 and a retention of 91.4 % after 50 cycles at a current density of 100 mA g−1. The favorable electrochemical properties of the lanthanide coordination polymers show potential application prospects in the field of electrode materials. 相似文献
70.
De-Qing Shi Abudhaim Feras Yi Liu 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2663-2673
In order to find high-acitivity and low-toxicity pesticidal lead compounds, a type of novel, asymmetric cyclic phosphorothonamides containing substituted pyridine were synthesized via the condensation reactions of 2-chloro-4-substitutedphenyl-5,5-dimethyl-1,3,2-dioxaphosphinane 2-sulfide with 3-aminomethylpyridine. The cis and trans isomers of the products were isolated by column chromatography on silica gel. The structures of the products were characterized by 1 H NMR, 31 P NMR, MS, and elemental analyses. The configuration of 3a was determined by X-ray diffraction analysis. The results of the preliminary bioassay showed that the new compounds possess potential fungicidal activities. 相似文献