染料敏化太阳能电池载流子传输的数值模拟

由于在染料敏化太阳能电池(dye-sensitized solar cell, DSSC)中存在染料弛豫、半导体薄膜中电子与氧化态染料分子发生反应和电子在电解质中与氧化态离子复合等不利反应,利用一个更完善的DSSC载流子传输模型对电池的光电性能进行模拟就显得非常重要。为此,本文基于由多重俘获理论建立的DSSC中的包括电子、染料阳离子、碘化物和三碘化物在内的载流子传输模型,数值模拟得到了不同TiO₂薄膜厚度、不同入射光强度与不同染料分子吸收系数下DSSC的J-V曲线。结果表明,随着TiO₂薄膜厚度的增加,太阳能电池的短路电流密度增大,开路电压减小,光电转换效率先增大后减小。当DSSC的TiO₂薄膜厚度为20 μm时,光电转换效率达到最大值7.41%,同时光电转换效率随入射光强度与染料分子吸收系数的增大均有一定程度提高,其中在吸收系数为4 500 cm^-1时,光电转换效率为6.73%。以上结果可以为改进DSSC的光电性能提供理论指导。

Numerical Simulation of Carrier Transmission in Dye-Sensitized Solar Cells

There are some adverse reactions in dye-sensitized solar cells (DSSC), such as dye relaxation, electrons in semiconductor films react with oxidized dye molecules and electron recombination with oxidized ions in electrolyte. It is very important to use a more sophisticated DSSC carrier transport model to simulate the photoelectric performance of the battery. Therefore, this paper is based on the carrier transport model including electron, dye cation, iodide and triiodide in DSSC established by multiple capture theory. The J-V curves of DSSC with different TiO₂ film thickness, different incident light intensity and different dye molecular absorption coefficient were obtained by numerical simulation. The results show that with the increase of TiO₂ film thickness, the short-circuit current density of solar cells increases, the open circuit voltage decreases, and the photoelectric conversion efficiency first increases and then decreases. When the TiO₂ film thickness of DSSC is 20 μm, the photoelectric conversion efficiency reaches the maximum value of 7.41%. At the same time, the photoelectric conversion efficiency increases with the increase of incident light intensity and dye molecular absorption coefficient. When the absorption coefficient is 4 500 cm^-1, the photoelectric conversion efficiency is 6.73%. The above analysis and research results can provide theoretical guidance for improving the photoelectric performance of DSSC.