A TiO₂ electrode coated with a thin film of SrTiO₃ was synthesized for photoelectrochemical application.
The TiO₂ colloidal solution was prepared by grinding in a mortar with a pestle 6 g of TiO₂ powder in 2 ml of distilled H₂O and 0.2 ml of acetylacetone; the substances were ground for 40 min. Finally, 8.0 ml of distilled water and 0.1 ml of Triton X-100 were slowly added with continuous mixing for 10 min. Several drops of this solution were spread onto the electrode surface using a glass rod. The electrode was dried in air and fired at 450 oC for 30 min, cooled to 70 oC and then immersed in a 0.5 X 10-3 mol L-1 ethanolic solution of the sensitizer dye cis-bis (isothiocyanato)bis(2,2’-bipyridyl-4,4’-dicarboxilic acid) – ruthenium (II), Ruthenium-535 from Solaronix for 16 h at room temperature. The gel polymer electrolyte based on poly (ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidylether) / P(EO-EM)78:22, g-butyrolactone as plasticizer, 12-crown-4 ether, LiI and I2 was prepared.
The results indicate that the TiO₂-SrTiO₃ core-shell electrodes provide a significant increase in photovoltage resulting in a 10% improvement of the conversion efficiency of the solar cell.