染料敏化太阳电池中TiO_2薄膜微结构相关动力学研究

INVESTIGATION OF CORRELATIVE KINETIC BASED ON THE MICROSTRUCTURE OF TiO_2 FILM IN DYE-SENSITIZED SOLAR CELLS

采用溶胶-凝胶法制备尺寸大小20nm和300nm的两种TiO2颗粒,二者以不同比例掺杂制备纳米多孔薄膜并应用于染料敏化太阳电池(DSC)中。采用强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术研究薄膜微结构变化对电子传输动力学过程的影响,进而分析大颗粒掺杂对电池性能影响的内在原因。结果表明,TiO2大颗粒作为光散射中心使光程增加可有效增大光强,但掺杂比例与染料吸附量存在竞争进而影响光吸收,研究表明:掺杂20wt%大颗粒纳米薄膜制备的DSC具有最佳性能,相比未掺杂的DSC,掺杂20wt%大颗粒的DSC短路电流Jsc从10.99mA/cm2增加到12.04mA/cm2,光电转换效率η增大8.2%。随TiO2大颗粒掺杂比例增大,电子传输时间τd减小。

Two different size of TiO2 particles with diameters of 20nm and 300nm were prepared by sol-gel method, and they were mixed with different ratio to prepare nanoporous films which were applied to dye-sensitized solar cells （DSC）. Using the intensity-modulated photocurrent spectroscopy （IMPS） and intensity-modulated photovohage spectroscopy （IMVS） measurements, the effect of the microstructure changes in the thin films on the kinetics of electron thansport was investigated, and then the intrinsic causes of the doping of larger TiO2 particles influences the performance of DSC was analyzed. It is found that the traveling distance of light within the TiO2 porous film can be extended and the light intensity can be enhanced effectively by doping larger TiO2 particles as light scattering centers, but which also influence the dye absorption amount and then influence optical absorption in the film. The result of the experiments showed that the DSC with the film doped with 20wt% larger particles has the best performance. The short-circuit current density Jsc of the doped DSC varied significantly from 10. 99mA/cm2 to 12.04mA/cm2 and the conversion efficiency increase by 8.2%. The eletron transport time , decreases with the increasing of the ratio of larger TiO2 particles doped in nanoporous film.