The different Sn doped TiO₂ nanoparticles were prepared by a sol-gel process, and also mainly characterized by the surface photovoltage spectrum (SPS) and the electrical field induced surface photovoltage spectrum (EFISPS). The effects of calcining temperature and Sn dopant content on the properties of photoinduced charges of TiO₂ were discussed in details, and the relationships between the structure and bound excitons as well as the characteristics of bound excitons of the as-prepared samples were revealed. The results showed that the SPS responses related to the bound excitons could exhibit only in the TiO₂ samples containing a certain amount of rutile, especially for those samples with the coexistence of the anatase and rutile. Sn dopant with appropriate content not only enhanced greatly the intensity of SPS responses related to the band-band transitions of TiO₂, but also made the intensity of SPS responses related to the bound excitons increase markedly.

Key words: TiO₂, gol-gel, doping, tin, surface photovoltage, bound exciton