Low-temperature synthesis of anatase thin films on glass and organic substrates by direct deposition from aqueous solutions

Crystalline titania thin films were obtained on glass and various kinds of organic substrates at 40-70°C by deposition from aqueous solutions of titanium tetrafluoride. Transparent films consisting of small anatase particles (∼20 nm) exhibited excellent adhesion to relatively hydrophilic surfaces. Uniform coatings were successfully prepared on substrates with complex shapes such as cotton and felt fiber. Growth rate and particle size were controlled by both the deposition conditions and the addition of an organic surfactant. Organic dyes were incorporated into the anatase films using organic-dye dissolving solutions and a surfactant. The photo-catalytic property of the titania films deposited in the precursor solutions at relatively low temperatures was identified as that of thermally crystallized anatase.