Low Temperature Fabrication of Titanium Oxide Composite Films by Hot-Water Treatment and Application for Dye-Sensitized Solar Cells

Abstract

We found that anatase TiO₂ nanocrystals were formed in the titania gel by treating with hot-water at 90°C under ambient pressure. The amount of the precipitated anatase nanocrystals increased with hot-water treatment time. Crystalline TiO₂ composite films were successfully prepared from the film composed of TiO₂ (P25) nanoparticles and titania gel by subsequent hot-water treatment at 90°C. TiO₂ nanoparticles were interconnected by the sol-gel derived, partially crystallized titania by the continuing hot-water treatment. A dye-sensitized solar cell (DSSC) using the hot-water treated TiO₂ composite film showed 1.9 mA cm⁻² of short-circuit current density and 0.6 V of open-circuit voltage. The fill factor (ff) and conversion efficiency (η) were 0.63 and 0.71%, respectively.