简易模板剂法制备多级介孔TiO2微球及其在染料敏化太阳能电池中的性能

采用模板剂法一步合成分级结构的介孔TiO₂微球, 考察了烷基胺类模板剂中烷基链长度对介孔TiO₂微球合成及性能影响. 将其应用于染料敏化太阳能电池的光阳极半导体薄膜中, 得到了9.5%-10.1%的高能量转换效率. X射线衍射(XRD)、物理吸附仪(BET)、扫描电镜(SEM)等的分析结果表明: 分级结构介孔TiO₂微球的晶相为纯锐钛矿型; 介孔TiO₂微球表面粗糙, 的纳米粒子堆积形成, 使微球具有介孔性质和较适宜的比表面积. 介孔TiO₂微球堆积形成了利于物质扩散的通道并具有良好的光散射效果; 同时微球介孔粗糙表面保证了染料的大量吸附, 从而提高了电池的光电流. 通过电化学阻抗分析结果验证了分等级结构介孔TiO₂微球光阳极有利于电解液的传输和物质扩散的优异性能.

A Simple Template Synthesis of Hierarchically Mesoporous TiO2 Microsphere for Dye-Sensitized Solar Cells

Mesoporous TiO₂ microspheres were synthesized using a simple template method. The effect of the alkyl chain length on the synthesis and properties of the TiO₂ microspheres was studied. A high power conversion efficiency (9.5%-10.1%) was attained by the dye-sensitized solar cells (DSCs) fabricated with the hierarchically mesoporous TiO₂ microsphere films. The physical properties of the TiO₂ microspheres were analyzed by X-ray diffraction (XRD), N₂ physisorption (BET), and scanning electron microscopy (SEM). The results indicated the TiO₂microsphere crystal structure to be in the pure anatase phase; the rough surface microstructure of the TiO₂ microspheres, formed through accumulation of nanocrystalline (14-18 nm diameter) TiO₂ particles, provides a proper large surface area and mesoporous structure. The hierarchically mesoporous TiO₂ microspheres can form good paths for mass transport, and also act as light scattering layers for efficient light harvesting. Meanwhile, the rough TiO₂ microsphere surface ensures a sufficient amount of dye uptake, and consequently improves the photo-generated electron density. Electrochemical impedance analysis demonstrated the advantage of using microspheres for mass transport in electrolytes.