强度调制光电流谱研究纳晶薄膜电极过程

Study of the Kinetics of Nanocrystalline Semiconductor Thin Film Electrode Processes by Intensity Modulated Photocurrent Spectroscopy

用强度调制光电流谱研究半导体纳晶薄膜电极光生电荷的界面转移和输运动力学过程．从测量不同外加电压和不同硫化钠溶液浓度下ＣｄＳｅ纳晶薄膜电极的光电流响应得到了参数：归一化稳态光电流和表面态寿命，分析界面空穴的直接转移和通过表面态的间接转移过程．通过测量不同背景光强下ＴｉＯ２纳晶薄膜电极的电子扩散系数研究电子输运过程．应用ＨＣｌ化学处理方法明显增大了电子扩散系数，改善了电子在ＴｉＯ２纳晶薄膜电极中的输运性能．

Photogenerated charge carriers transfer and transport kinetics of nanocrystalline semiconductor thin film electrodes were studied by Intensity Modulated Photocurrent Spectroscopy (IMPS). Measuring the applied potential and sodium polysulfide solution concentration dependence of IMPS response of nanocrystalline CdSe electrodes, the interfacial holes transfer including direct process and indirect process via surface states were analyzed in terms of the parameters: normalized steady state photocurrents and surface states lifetimes. The transport processes of electrons were examined by determining the electron diffusion coefficient of nanocrystalline TiO2 electrodes obtained at different intensities of background light. HCl chemical treatment led to the increase of electron transport coefficient effectively indicating the improvement of electrons transport behavior in the nanocrystalline TiO2 electrodes.