Dye Adsorption Characteristics of Anatase TiO2 Film Prepared in an Aqueous Solution

Anatase TiO₂ film was deposited on SnO₂: F substrate in aqueous solution. The film had an assembly of acicular TiO₂ nanocrystals on the surface. The crystals grew along the c-axis, i.e. perpendicular to the substrate. Dye adsorption increased with film thickness. Intensity of photoluminescence originating from the dye adsorbed on the nanostructured film after annealing was 3 times higher than that of thicker particulate film constructed of TiO₂ nanoparticles (P25). Additionally, dye adsorption property of the film without annealing was two times higher than the film with annealing. Consequently, the as-deposited film had high dye adsorption property which is about 6 times higher that that of thicker particulate film constructed of TiO₂ nanoparticles (P25). Assemblies of acicular crystals on the surface increased the surface area and amount of dye adsorption. The film may be useful for biomolecule sensors and dye-sensitized solar cells.