染料敏化太阳电池中TiO_2膜内电子传输和背反应特性研究

Research on the electron transport and back-reaction kinetics in TiO_2 films applied in dye-sensitized solar cells

采用强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)研究电池内部电子传输机理和电子背反应动力学特性.利用理论表达式对不同TiO2多孔膜厚度(d)的电池实验数据进行了拟合,得到了电池的吸收系数(α)、电子扩散系数(Dn)、电子寿命(τn)、电子传输时间(τd)和入射单色光光电转化效率(IPCE)等微观参数的数值.研究表明:膜薄有利于加快电子传输,膜厚有利于提高光生电子浓度,进而从微观层面上研究了薄膜厚度对于电池内部电子产生、传输和复合过程的影响.

The mechanics of electron transport and properties of back-reaction kinetics were investigated by intensity-modulated photocurrent spectroscopy （IMPS） and intensity-modulated photovoltage spectroscopy （IMVS）. The theoretical expression fitting the experimental data of five different porous TiO2 films applied in DSC and the values of absorption coefficient （ a ）, the diffusion coefficient （ Dn ）, electron lifetime （ rn ）, the electron transit time （ rd ） and IPCE can be obtained. The results showed that the electrons transit faster in the thinner films, while the electron concentration increase in the thicker films. The influence of film thickness on the electron generation, transport and recombination processes was investigated in the microscopic level in this paper.