Nanocrystalline mesoporous strontium titanate as photoelectrode material for photosensitized solar devices: Increasing photovoltage through flatband potential engineering

Nanocrystalline SrTiO₃ is synthesized by hydrothermal treatment of nanocrystalline titanium dioxide in the presence of strontium hydroxide. Working photoelectrochemical solar cells are produced using these nanometer-sized semiconductor particles as photoelectrode materials. At AM 1.5, measured open circuit voltages were roughly 100 mV higher than in solar cells produced using nanocrystalline titanium dioxide (anatase), in agreement with a simple relation between semiconductor conduction band edge and open circuit voltage for these cells. Photocurrents measured in the SrTiO₃ cells were roughly 1/3 those measured with TiO₂ (anatase) -based cells. On the basis of flash laser photolysis and absorptance studies, we suggest that low dye loading and possibly suboptimal dye-oxide interactions can be the cause for the relatively low photocurrents in the SrTiO₃ system.