染料敏化太阳电池中常相角元件特性模拟及应用研究

Studies on Simulation and Application of Characteristics of Constant Phase Element and in Dye-sensitized Solar Cells

电化学阻抗谱(EIS)可在宽频率范围内研究染料敏化太阳电池(DSC)内部阻抗信息。由于DSC内部主要接触界面的电容存在弥散效应,所以采用常相角元件(CPE)代替电容构建等效电路来解析EIS谱。通过模拟和分析CPE在不同指数变化下的频率响应特性,研究了CPE指数对与等效电阻并联的RC电路阻抗特性影响以及电容与CPE的换算。通过实验,在3个频率区间分别利用CPE和电容对DSC的EIS谱进行拟合,分析了CPE在DSC接触界面电子转移过程和动力学常数提取中的应用。结果表明,CPE指数决定了元件的性能,采用CPE代替电容更加适合构建DSC等效电路,经过计算即可利用CPE获得DSC内部电子界面转移动力学常数。

Electrochemical impedance spectroscopy（EIS）may be used to study the internal impedance information of dye-sensitized solar cells（DSC）in the range of wide frequency.There is capacitance dispersion effect due to the roughness and inhomogeneity of main contact interfaces in DSC.A constant phase element（CPE）is an equivalent electrical circuit component that models the behavior of an imperfect capacitance.This paper simulates and analyzes the frequency response characteristic of CPE with several different indexes.The effect of CPE index on impedance of RC circuit and the conversion between CPE and a pure capacitance are studied.CPE and capacitance are used respectively in three distinct frequency ranges to fit EIS spectrum through experiments.The application of CPE in the interfacial electron transfer process and extraction of kinetic parameters are analysed.The results show that the CPE index determines the element performance and it is more suitable to use a CPE instead of a pure capacitance for constructing EIS equivalent circuits.DSC internal electron transfer kinetic constants can be obtained by using CPE after a simple calculation.