Spatial and Orientational Templating of Semiconducting Polymers in a Cholesteric Liquid Crystal

A one‐dimensional pattern‐forming state of a cholesteric liquid crystal (CLC) is used as a template for the self‐organization of ordered, spatially orientated, acetylene‐based semiconducting polymers. The polymers are formed by metathesis reaction with all chemical components contained in an ordinary electro‐optic cell. The polymer morphology consists of parallel ～ 1 μm thick bundles, uniformly spaced at ～ 10 μm over the full macroscopic active area of the cell substrates. The polymer templating can be explained by a model that predicts a corrugation in polymer density determined by the spatially periodic profile of the orientational energy density associated with the pattern‐forming CLC state.     

TiO2-V2O5陶瓷的复合特性研究

报道了TiO2-V2O5陶瓷的制备工艺和复合功能特性的研究结果。该陶瓷使用传统的陶瓷工艺制备，并测量了其性能参数。该陶瓷具有复合功能特性，即半导体特性、介电特性和压敏特性。用TiO2—V2O5陶瓷可以制备复合功能陶瓷器件。     

AST液相掺杂对低电阻率、高抗电强度BaTiO3半导瓷显微结构及电性能影响

通过改变低电阻率BaTiO3半导体陶瓷中液相添加剂AST的含量，采用XRD和SEM显微分析方法研究了AST含量对低电阻率，高抗电强度BaTiO3半导体陶瓷显微结构的影响，研究结果指出，BaTiO3半导体陶瓷中AST的引入量对晶界厚度的控制存在两个临界点，晶界厚度对低电阻率，高抗电强度BaTiO3半导体陶瓷的显微结构和电性能产生重要影响。     

Optocoupler made from semiconducting polymers

Optocouplers (optoisolators) were fabricated using semiconducting polymers. The input unit is a polymer light emitting diode with an external quantum efficiency of ∼1% photons/electron. The output unit is a polymer photodiode with a quantum yield of ∼35% electrons/photon at 590 nm. Both units can be operated at bias voltages sufficiently low to be compatible with TTL and complementary metal-oxide semiconductor logic circuits. Since the transfer characteristic is nearly linear, the polymer optocoupler can be used in analogue circuits as well. The current transfer ratio reaches 2 × 10⁻³ under-10V reverse bias, comparable to that of commercial inorganic optocouplers.     

Field Emission and Cathodoluminescence of ZnS Hexagonal Pyramids of Zinc Blende Structured Single Crystals

Single‐crystal hexagonal pyramids of zinc blende ZnS are fabricated by facile thermal evaporation in an ammonia atmosphere at 1150 °C. It is found that ZnS pyramids grow along the [111] crystal axis and possess a sharp tip with a diameter of ～10 nm and a micrometer‐sized base. The structural model and growth mechanism are proposed based on crystallographic characteristics. This unique ZnS pyramid structure exhibits a low turn‐on field (2.81 V µm^?1), a high field‐enhancement factor (over 3000), a large field‐emission current density (20 mA cm^?2), and good stability with very small fluctuation (0.9%). These superior field‐emission properties are clearly attributed to the pyramid morphology, with micrometer‐sized bases and nanotips, and high crystallinity. Moreover, a stable UV emission of 337 nm at room temperature is observed and can be ascribed to the band emission of the zinc blende phase. These results suggest that the ZnS hexagonal pyramids can be expected to find promising applications as field emitters and optoelectronic devices.     

绝缘子防冰过程中半导体硅橡胶涂层电阻的配置

目前导线防覆冰技术已经相对成熟,而绝缘子的防覆冰方法仍处于实验室研究阶段,其中在绝缘子下表面涂覆半导体有机硅橡胶涂层的防覆冰方法已在人工气候室取得一定效果。为对半导体硅橡胶涂层电阻值的配置及相关的污闪问题进行研究,首先建立了基于热力学理论的绝缘子防冰热平衡模型,通过模型估算单片XP–70绝缘子涂层的电阻值,并在人工气候室内进行了防覆冰试验验证;重点讨论了电压、预染污方式对防冰效果的影响以及涂层对绝缘子污闪电压的影响。理论和试验结果表明:涂层电阻的范围在0.1~0.3M以下时,涂层绝缘子具有较好的防冰效果,此结果可为中国输电线路及绝缘子防覆冰工作提供一定的指导。     

CIS光伏材料的发展

CuInSe2(CIS)是一种光伏特性仅次于单晶硅的材料。CIS薄膜太阳能电池多年来保持着薄膜太阳能电池的世界记录，受到世界各国科学家的关注。综述了近年来对CIS材料的理论与试验研究，系统总结了CIS材料制备方法、材料微观结构对光伏特性的影响以及今后的发展方向。     

Optically Tunable Field Effect Transistors with Conjugated Polymer Entailing Azobenzene Groups in the Side Chains

Semiconducting conjugated polymers with photoswitching behavior are highly demanded for field‐effect transistors (FETs) with tunable electronic properties. Herein a new design strategy is established for photoresponsive conjugated polymers by incorporating photochromic units (azobenzene) into the flexible side alkyl chains. It is shown that azobenzene groups in the side chains of the DPP (diketopyrrolopyrrole)‐quaterthiophene polymer ( PDAZO ) can undergo trans/cis photoisomerization in fully reversible and fast manner. Optically tunable FETs with bistable states are successfully fabricated with thin films of PDAZO . The drain‐source currents are reduced by 80.1% after UV light irradiation for ≈28 s, which are easily restored after further visible light irradiation for ≈33 s. Such fast optically tunable FETs are not reported before. Moreover, such current photomodulation can be implemented for multiple light irradiation cycles with good photofatigue resistance. Additionally, thin film charge mobility of PDAZO can be reversibly modulated by alternating UV and visible light irradiations. On the basis of theoretical calculations and GIWAXS data, it is hypothesized that the dipole moment and configuration changes associated with the trans‐/cis‐photoisomerization of azobenzene groups in PDAZO can affect the respective intra‐chain and inter‐chain charge transporting, which is responsible for the optically tunable behavior for FETs with thin films of PDAZO .