Photoinduced electron transport in dye-containing titania gel films

Abstract

Amorphous dye-containing titania gel films were prepared on ITO electrodes coated with a crystalline titania foundation from titanium alkoxide sols containing a dye at room temperature. Photoinduced electron transport in the amorphous titania gel film was investigated by spectroscopic and photovoltaic measurements. Influences of the structure and morphology of the multilayered film on the photoelectron transport and electrically conductive properties were discussed. The photocurrent was observed from only the layer contacting the crystalline titania foundation. The electron transport from the amorphous upper layers was limited. Steam treatment of the electrodes improved the electron transport due to crystallization of the amorphous titania to anatase accompanied by enhancement of its electrical conductivity. The efficiency of the dye-sensitized electron transport in the steam-treated titania film was close to that of the anatase film prepared by heating at 773 K. The dye-containing titania layers functioned as efficient sensitizers.