利用激子敏化层研究蓝色有机发光器件的激子扩散问题

制备了发光层采用CBP:N-BDAVBi掺杂系统的蓝色有机电致发光器件.将窄带隙的红色荧光染料DCJTB超薄层作为激子敏化层插入器件发光层的不同位置,通过对所制备的器件电致发光光谱的分析,定性研究了器件激子产生区域的位置,同时对激子的扩散问题作进一步分析.

介孔ZnO、NiO的叠层染料敏化太阳电池的研制

染料敏化太阳电池具有成本廉价、制作工艺简单以及性能稳定的特点,为人类廉价和方便地使用太阳能提供了有效的方法。目前,染料敏化太阳电池的最高转换效率由n-DSSCs保持,利用介孔TiO2纳米晶作电极材料,转换效率达到了12%,但是要进一步提高电池效率遇到了挑战。采用ZnO光阳极和NiO光阴极,分别以N719和C343为光敏剂,研究了组建叠层染料敏化太阳电池的可行性。J-V测试结果表明,从NiO端照射时,pn-DSSCs的开路电压Voc可达694mV,为相应的n-DSSCs和p-DSSCs的开路电压之和。器件的Jsc、FF和h分别为2.73mA/cm2、34.8%、0.66%。研究了电解质中I2与I-相对浓度变化对电池性能和电荷迁移电阻的影响,随着I2/I-浓度比从1∶20增加到1∶1,电池效率从0.71%增加到0.98%。

基于p型光电极的染料敏化太阳能电池研究进展

基于p型光电极的染料敏化太阳能电池是一种受到广泛关注的新型太阳能电池。根据电池的结构不同可以将其分为p型和p-n叠层型染料敏化太阳能电池。其中p-n型叠层染料敏化太阳能电池的理论光电效率可以达到43%,高于传统的基于n型TiO_2光阳极的染料敏化太阳能电池理论效率(30%),引起了科学界的高度关注。本文将总结基于p型光电极染料敏化太阳能电池(p型和p-n型叠层器件)的研究成果,重点介绍用于p型和p-n型叠层染料敏化太阳能电池的电极材料,染料及电解质的研究进展;同时总结目前该类电池发展中亟需解决的问题以及进一步提高器件效率的途径。

一种新的太阳能光电转换装置

据英国 Nature,2003,421:586报道,美国科学家最近发明了一种新的非硅太阳能光电转换装置。这个装置具有多层结构,最上一层是一种染料分子用来吸收光子,它们吸附在一层金膜的表面,然后是一层二氧化钛(TiO_2)半导体,最后一层是二氧化钛载体。金膜和二氧化钛半导体之间存在一个自发生成的局域电场,这个局域电场产生一个电势势垒。

Optimization of Composite Wind Turbine Blade Based on Modal Sensitivity

This study develops a method for the full-size structural design of blade,involving the optimal layer thickness configuration of the blade to maximize its bending stiffness using a genetic algorithm.Numerical differentiation is employed to solve the sensitivity of blade modal frequency to the layer thickness of each part of blade.The natural frequencies of first-order flapwise and edgewise modes are selected as the optimal objectives.Based on the modal sensitivity analysis of all design variables,the effect of discretized layer thickness on bending stiffness of the blade is explored,and 14 significant design variables are filtered to drive the structural optimization.The best solution predicts an increase in natural frequencies of first-order flapwise and edgewise blade modes by up to 12%and 10.4%,respectively.The results show that the structural optimization method based on modal sensitivity is more effective to improve the structural performance.

Julolidine-labelled fluorinated block copolymers for the development of two-layer films with highly sensitive vapochromic response

Fluorinated block copolymers composed of a polystyrene(Sx) first block and a polyacrylate second block carrying hydrophobic/lipophobic perfluorohexyl side chains(AF) were prepared by atom transfer radical polymerization(ATRP). Fluorescence emission properties were imparted to the copolymers by incorporation in the second block of a julolidine-based fluorescent molecular rotor(JCBF). The synthesized block copolymers were used as the fluorescent low-surface energy thin top-layer onto a polystyrene bottom-layer to produce novel two-layer film vapochromic sensors. Contact angle and X-ray photoelectron spectroscopy(XPS) measurements revealed that the two-layer film surfaces were hydrophobic and lipophobic at the same time and highly enriched in fluorine content as a result of the effective segregation of the perfluorinated tails to the polymer-air interface.The fluorescence intensity of the two-layer films decreased significantly when they were exposed to vapours of organic solvents,including tetrahydrofurane, chloroform, and trifluorotoluene. However, an AF content-dependent sensing behaviour was also observed, with the two-layer films containing the copolymer with the shorter fluorinated block giving a more rapid and almost quantitative decrease in fluorescence variation. Fluorescence emission of the films was also proved to vary with temperature.Both the vapochromic and thermochromic responses were reversible after successive solicitation cycles. The fluorescence variation of the two-layer films was much more marked than that of the corresponding PS/JCBF blend, thus providing a system potentially applicable as highly sensitive volatile organic compound(VOC) sensor, thanks to the active role of the fluorinated block in promoting the migration of the fluorophore to the outermost surface layers.

Node shift method for stiffness-based optimization of single-layer reticulated shells

This paper presents a node shift method to find the optimal distribution of nodes in single-layer reticulated shells. The optimization process searches for the minimum strain energy configuration and this leads to reduced sensitivity in initial imper- fections. Strain energy sensitivity numbers are derived for free shift and restricted shift where nodes can move freely in the 3D space or have to move within a predefmed surface respectively. Numerical examples demonstrate the efficiency of the proposed approach. It was found that optimized structures achieve higher ultimate load and are less sensitive to imperfections than the initial structure. The configuration of the final structure is closely related to factors like the initial structural configuration, spatial conditions, etc. Based on different initial conditions, architects can be provided with diverse reasonable structures. Furthermore, by amending the defined shapes and nodal distributions, it is possible to improve the mechanical behavior of the structures.

SnO_2 nanosheet as a photoanode interfacial layer for dyesensitized solar cells

SnO2 nanosheet films about 200 nm in thickness are successfully fabricated on fluorine-doped tin oxide （FTO） glass by a facile solution-grown approach. The prepared SnO2 nanosheet film is appfied as an interfacial layer between the nanocrystalline TiO2 film and the FTO substrate in dye-sensitized solar cells （DSCs）. Experimental results show that the introduction of a SnO2 nanosheet film not only suppresses the electron back-transport reaction at the electrolyte/FTO interface but also provides an efficient electron transition channel along the SnO2 nanosheets, and as a result, increasing the open circuit voltage and short current density, and finally improving the conversion efficiency for the DSCs from 3.89% to 4.62%.

Synthesis of dispersed long single-crystalline TiO_2 paste and its application in DSSC as a scattering layer

Ti O2 nanowire(NW) is one of the potential scattering layer materials in dye-sensitized solar cells(DSSCs) owing to its fast electron conductivity and excellent light scattering property resulting from its one-dimensional(1D) morphology. However, Ti O2 NWs used as scattering layers in previous work were either aggregated or shortened into shuttles that cannot use their unique 1D properties. In this paper, we present the preparation of a well-dispersed long NW paste(exceeding 1 ?m) by a mild method and used as a scattering layer in DSSC. The paste achieved a photoconversion efficiency of 5.73% and an efficiency enhancement of 12% compared with commercial scattering layer(P200 paste). Compared with the DSSC without a scattering layer, an efficiency enhancement of 54.9% was achieved. Also, the largest efficiency of 6.89% was obtained after optimization of photoanode thickness. The photoanodes were investigated through dye desorbed experiments and transmission spectra, which suggested that P25 nanoparticles with the as-prepared NW scattering layer loaded more dye than those with P200 paste. These results indicate that well-dispersed long NW paste has a potential application in scattering layers.