AFM study of advanced composite materials for organic photovoltaic cells with active layer based on P3HT:PCBM and chiral photosensitive liquid crystalline dopants

Advanced composite materials aimed for construction of organic photovoltaic cells have been studied by atomic force microscopy (AFM). The composites are based on poly(3-hexylthiophene) (P3HT), [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM) and two different chiral photosensitive liquid crystalline (LC) materials. The objective of the study was to examine the nanoscale morphology of the active layer without and after annealing at specific temperature. The preliminary results of AFM observation of the morphological changes done on the investigated composites revealed an increase in the surface ordering. The surface area ratio decreases for both studied composites, while the basic roughness parameters (S_a and S_q) have been found toughly dependent on the structure of the photosensitive LC dopant.     

Effects of post-annealing on structural, optical and electrical properties of Al-doped ZnO thin films

Aluminum-doped zinc oxide (AZO) films were deposited at 400 °C by radio-frequency magnetron sputtering using a compound AZO target. The effects of annealing atmospheres as well as hydrogen annealing temperatures on the structural, optical and electrical properties of the AZO films were investigated. It was found that the electrical resistivity varied depending on the atmospheres while annealing in air, nitrogen and hydrogen at 300 °C, respectively. Comparing with that for the un-annealed films, the resistivity of the films annealed in hydrogen decreased from 9.8 × 10⁻⁴ Ω cm to 3.5 × 10⁻⁴ Ω cm, while that of the films annealed in air and nitrogen increased. The variations in electrical properties are ascribed to both the changes in the concentration of oxygen vacancies and adsorbed oxygen at the grain boundaries. These results were clarified by the comparatively XPS analyzing about the states of oxygen on the surface of the AZO films. There was great increase in electrical resistivity due to the damage of the surfaces, when AZO films were annealed in hydrogen with a temperature higher than 500 °C, but high average optical transmittance of 80-90% in the range of 390-1100 nm were still obtained.     

Dependence of resistivity on structure and composition of AZO films fabricated by ion beam co-sputtering deposition

The correlation between the resistivity and the structure/composition in the aluminum doped zinc oxide (AZO) films fabricated by the ion beam co-sputtering deposition at room temperature was investigated. The various compositions of AZO films were controlled by the sputtered area ratio of Al to Zn target. The structure, Al concentrations and resistivities of the as-deposited films were determined by X-ray diffractometer (XRD), energy dispersive spectrometer (EDS) and four-point probe station, respectively. The lowest resistivity of the deposited film was 5.66 × 10⁻⁴ Ω-cm at the 0.7 wt.% aluminum concentration. The most intense ZnO (0 0 2) diffraction peak, the largest grain size, the longest mean free path, and the highest free carrier concentration in the film result in the lowest resistivity of 5.66 × 10⁻⁴ Ω-cm at room temperature; simultaneously, the thermal stability of the resistivity of the AZO film as a function of the sample temperature was investigated. Below 200 °C the film's resistivity was almost kept at a fixed value and the lowest resistivity of 4.64 × 10⁻⁴ Ω-cm at 247 °C was observed.     

磁控溅射中靶-基底距离与Si共掺对ZnO:Al薄膜性质的影响

使用射频磁控溅射, 在正方形石英衬底上沉积透明导电掺Al的ZnO(AZO)和Si共掺AZO(AZO:Si)薄膜. 系统研究了靶-基底距离(D_st)和Si共掺对AZO薄膜电学、光学性质的影响. 电阻率、载流子浓度和迁移率都强烈地依赖于靶-基底距离, 随着靶-基底距离的减少, 载流子浓度和迁移率都有显著的增加, 电导率也随之提高. 在靶-基底距离为4.5 cm处, 得到最低电阻率4.94×10^-4 Ω·cm, 此时的载流子浓度和迁移率分别是3.75×10²⁰ cm^-3和33.7 cm²·V^-1·s^-1. X射线光电子能谱(XPS)、X射线衍射(XRD)和边界散射模型被用于分析载流子浓度、迁移率和靶-基底距离的关系. 透射谱显示, 在可见-近红外范围内所有样品均有大于93%的平均透射率, 同时随着靶基距离的减少, 吸收边蓝移. AZO:Si表现出可与AZO相比拟的高电导和高透射光学特性, 但在热湿环境中却有着更好的电阻稳定性, 这在实际使用中很有意义.     

溶剂对溶胶-凝胶法制备的掺铝氧化锌透明导电薄膜性质的影响

采用溶胶-凝胶法在玻璃基底上制备得到了高透光率,高导电性的掺铝氧化锌薄膜。研究了溶剂对薄膜晶体结构,薄膜厚度,表面形貌,光学性质和电学性质的影响,结果表明:在相同的制备条件下,薄膜的厚度随溶剂沸点的升高而降低;低沸点溶剂制备的薄膜由c轴择优取向的六角纤锌矿结构的晶体构成,且比较致密;所有薄膜可见光区的透光率在85%以上;乙二醇独甲醚为溶剂制备的薄膜电阻率最低,为3.0×1-0 4Ωm。     

射频溅射功率对AZO薄膜结构及光电特性和热稳定性的影响

采用射频磁控溅射法,在玻璃基片上制备了ZnO:Al(AZO)透明导电薄膜。用X射线衍射(XRD)仪、紫外-可见分光光度计、方块电阻测试仪和台阶仪对不同溅射功率下Al掺杂ZnO薄膜的结晶、光学、电学性能、沉积速率以及热稳定性进行了研究。研究结果表明:不同溅射功率下沉积的AZO薄膜具有六角纤锌矿结构,均呈c轴择优取向;(002)衍射峰强和薄膜的结晶度随溅射功率的提高逐渐增强;随溅射功率的提高,AZO薄膜的透射率有所下降,但在可见光(380～780nm)范围内平均透射率仍80%;薄膜的方块电阻随溅射功率的增加逐渐减小;功率为160～200W时,薄膜的热稳定性最好,升温前后方块电阻变化率为13%。     

铜铟镓硒薄膜太阳能电池新型图形化透明前电极研究

为了优化铜铟镓硒薄膜太阳能电池的前电极,提高铜铟镓硒薄膜太阳能电池的效率,提出了一种可应用于铜铟镓硒薄膜太阳能电池的AZO/图案化Ag薄膜/AZO结构的前电极,中间层的Ag薄膜与电池顶层的金属栅线具有完全相同的图案和尺寸,并且位于金属栅线的正下方,这种新型结构可以提高电池前电极的电学性能,但对电池来说不会带来额外的光学损失。对比了新型前电极结构与几种传统前电极的电学和光学性能,并且制备了相应的电池进行了性能对比。实验结果表明,新型的前电极结构可以提高铜铟镓硒薄膜太阳能电池的短路电流,相对传统AZO电极,电池效率从13. 83%提高到14. 53%。本结构可以明显提高电池效率。     

非离子表面活性剂胶束增溶显色反应机理的研究 III:在Fe(III)-PAN-Triton X-100体系中胶束对金属离子反应活性的影响

Fe (III) and PAN form the complex Fe(PAN)2OH which can be extracted into CHCl3. The CHCl3 extract shows absorption maxima at 550 nm and 775 nm (log E550 = 4.06, log e775 = 4.08). In the Fe(III)--PAN--Triton X-100 system, two complex species (Fe(PAN)2)+ and/or Fe(PAN)2OH may be formed. (Fe(PAN)2)+ exhibits a stronger absorption peak at 550 nm (log E550 =4.36). In this paper the effect of Triton X-100 micelles on the Fe(III)-PAN reaction has been investigated in detail. We consider that the presence of high density of ethereal oxygen chains in Triton X-100 micelles enables to concentrate hydrated Fe(III) ions and change their existing state. Moreover, the micelles not only increase the reactivity of Fe(III), but also enhance the rate of the color reaction.     

含蒽醌基偶氮染料的合成及其吸收光谱的研究

高产率地合成了一系列1-氨基蒽醌与2-羟基-3-氨替酰氨萘酚(色酚)的偶氮染料, 对其进行了元素分析、红外光谱表征。研究了不同取代基对偶氮染料吸收光谱的影响, 考察了光照条件下该类偶氮染料在DMF稀溶液中吸收光谱的变化特征。     

航天探月工程科研成果转化的教学实验：仿生荷叶掺铝氧化锌薄膜应用于月尘防护

面向国家航天探月重大需求,将科研项目“仿生荷叶超疏水微纳结构防月尘性能研究”转化为本科生实验,主要内容为利用原子层沉积技术制备铝掺杂氧化锌(AZO)薄膜,结合水热法制备具有二级微纳结构的AZO涂层材料。该实验航天背景特色强,涉及化学、材料、航天等多学科交叉融合。学生从薄膜制备、表征技术、探讨除尘以及晶体生长机理等4个方面接受基本科研训练,与探月工程同频共振,有利于增强学生实践能力,使学生潜移默化感知社会脉搏,引导学生从事航天事业。