中文摘要：

TiO2作为一种宽带隙半导体材料，由于具有显著的光电响应、良好的化学稳定性和绿色环保性，在太阳能转换、光催化杀菌及污染处理等方面具有广泛的用途．纳米TiO2薄膜已被广泛应用于TiO2染料敏化太阳能电池（DSSC）．由于光生电荷在纳米TiO2薄膜电极中的传输直接决定DSSC的性能，所以深入研究光生电荷在纳米TiO2薄膜电极中的传输机理对提高DSSC性能极其重要．

英文摘要：

Transient photovohage （PV） technique was applied to investigate the separation and the transport mechanism of the photo-induced charge carriers on nano-TiO2 film electrode. The positive PV transients were observed whenever the light was incident from the gauze platinum（ top illumination） or the ITO electrode（ bottom illumination）. This implies that the photo-induced electrons always accumulate near the ITO. Simultaneously, it is found that under the singe pulse illumination, PV transient at bottom illumination needs a shorter time to reach its maximum than that at top illumination. This indicates that the photo-induced carriers are separated faster on TiO2/ITO interface than that in the bulk of the TiO2 film. These demonstrate the existence of the contact potential on the TiO2/ITO interface, with the downward band bending from the TiO2 to ITO, which may cause the excess carriers to be separated by drift. Under the repeated pulses illumination, the PV transients at top illumination remained unchanged, while those at bottom illumination This results from the trapping of the excess electrons on the TiO2/ITO interface. changed significantly.