基于Pechini溶胶–凝胶法的染料敏化太阳能电池的优化

Optimization of Dye-sensitized Solar Cells Prepared by Pechini Sol-Gel Method

采用Pechini溶胶–凝胶法一步反应工艺制备功能型的TiO_2薄膜,基于界面电荷复合效应探讨Pechini型TiO_2膜厚对电池光电性能的影响机制,并通过膜厚调控对电池性能进行优化。采用UV-Vis、电化学阻抗谱以及暗态I-V测试,系统研究了TiO_2膜厚对染料吸附量、界面电子复合过程以及电池光电性能的影响规律。结果表明,随着TiO_2膜厚增加,染料吸附量增加引起电池光捕获效率和光电流增加;同时,TiO_2膜中的电子寿命缩短,TiO_2/电解质界面的电子复合几率增大导致电池光电压下降。上述综合作用使得电池效率先增加后减小,并在膜厚为10.7μm时,光电转化效率达到最佳值7.75%(相同工艺条件下常规方法为6.56%)。

Functional TiO2 films were prepared by using a facile one-step Pechini Sol-Gel method. The intrinsical contribution mechanism of film thickness to the photo-to-electric performance of DSSC was explored with analysis of interfacial charge recombination effects, on which, the characteristics of DSSC were optimized via film thickness controlling. The influence of TiO2 film thickness on dye absorption, charge recombination process and photovoltaic performance of DSSC were by UV-Vis, electrochemical impedance spectroscopy and 1-V test under dark condition, respectively. The results show that as TiO2 film thickness increases, the light harvesting efficiency and photocurrent of DSSC increase, which were induced by the enhancement of dye absorption. However, the photovoltage decreases gradually with the increaese of electron recombination probability. As an increase, combination of the positive and negative effects above enables the Pechini-type DSSC efficiency first increase and then decline, with an optimum efficiency of 7.75% at the film thickness of 10.7 μm in contrast to 6.5% of the routine method.