简易模板剂法制备多级介孔TiO_2微球及其在染料敏化太阳能电池中的性能

A Simple Template Synthesis of Hierarchically Mesoporous TiO_2 Microsphere for Dye-Sensitized Solar Cells

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9.52%-10.15%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,是由14-18nm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.

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 TiO2 microsphere 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.