Chem. J. Chinese Universities ›› 2006, Vol. 27 ›› Issue (3): 550.

• Contents • Previous Articles     Next Articles

Studies on Tansport Mechanism of Photo-induced Charge Carrier on Nano-TiO2 Film Electrode Using Transient Photovoltage Technique

ZHANG Qing-Lin,WANG De-Jun*,WEI Xiao,ZHAO Qi-Dong,LIN Yan-Hong,YANG Min   

  1. College of Chemistry,Jilin University,Changchun 130023,China
  • Received:2005-09-23 Online:2006-03-10 Published:2006-03-10

Abstract:

Transient photovoltage(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 changed significantly. This results from the trapping of the excess electrons on the TiO2/ITO interface.

Key words: Transient photovoltage; TiO2; Contact potential; Transport of the photo-induced charge carrier

CLC Number: 

TrendMD: