利用瞬态光电压技术对纳米TiO_2薄膜电极中光生电荷传输机理的研究  

Studies on Tansport Mechanism of Photo-induced Charge Carrier on Nano-TiO_2 Film Electrode Using Transient Photovoltage Technique

作　　者：张清林[1] 王德军[1] 魏霄[1] 肇启东[1] 林艳红[1] 杨敏[1] 

机构地区：[1]吉林大学化学学院,长春130023

出　　处：《高等学校化学学报》2006年第3期550-552,共3页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20273027;20473033);吉林省科技发展基金(批准号:20040503);教育部博士学科点基金(批准号:020183008)资助.

摘　　要：Transient photovoltage(PV) technique was applied to investigate the separation and the transport mechanism of the photo-induced charge carriers on nano-TiO_ 2 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 TiO_ 2/ITO interface than that in the bulk of the TiO_ 2 film. These demonstrate the existence of the contact potential on the TiO_ 2/ITO interface, with the downward band bending from the TiO_ 2 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 changed significantly. This results from the trapping of the excess electrons on the TiO_ 2/ITO interface.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.

关 键 词：瞬态光电压 TIO2 接触势垒 光生电荷传输 

分 类 号：O643[理学—物理化学]