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 nanocrys talline titanium dioxide in the presence of strontium hydroxide. Working ph otoelectrochemical solar cells are produced using these nanometer-sized sem iconductor particles as photoelectrode materials. At AM 1.5, measured open circuit voltages were roughly 100 mV higher than in solar cells produced us ing nanocrystalline titanium dioxide (anatase), in agreement with a simple relation between semiconductor conduction band edge and open circuit voltag e 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 l aser photolysis and absorptance studies, we suggest that low dye loading an d possibly suboptimal dye-oxide interactions can be the cause for the relat ively low photocurrents in the SrTiO3 system.