Facilitated by TiO2 particles absorbing La3+ in hydrosol, La-doped TiO2 was prepared by a sol-hydrothermal method. Electron paramagnetic resonance and Brunauer-Emmett-Teller surface area analysis showed that the obtained La-doped anatase TiO2 surface provided a higher density of oxygen vacancies without a change in the Brunauer-Emmett-Teller surface area. A theoretical calculation was carried out to explain the generation mechanism of the increased oxygen vacancies. The results showed that the La-doped anatase TiO2 (101) surface tends to engender oxygen vacancies. The photoelectric conversion efficiency of dye-sensitized solar cells fabricated from 1mol%La-doped TiO2 reached 6.72%, which gave an efficiency improved by 13.5% compared with that of the cells fabricated from pure TiO2. The improvement in the efficiency was ascribed to more dye absorbed on the surface of TiO2.

Increasing the Oxygen Vacancy Density on the TiO2 Surface by La-Doping for Dye-Sensitized Solar Cells. Zhang, J., Zhao, Z., Wang, X., Yu, T., Guan, J., Yu, Z., Li, Z., Zou, Z.: Journal of Physical Chemistry C, 2010, 114[43], 18396-400