Characteristics of SiO2-TiO2 complex thin films prepared by sol method

Uniform and transparent nanoscale SiO2-TiO2 complex thin films with thickness of about 100 nm were prepared by sol method on glass substrates at room temperature in air. The photo-induced activity of the films has been measured. The effect of annealing on the hydrophilicity and the photocatalysis activity of the films were studied. The chemical states of the elements on the surface and near the surface were measured by XPS. The results show that the Ti in/on the surface of the films exists not only as Ti4+ but also as Ti3+. At the same time, part of the Ti4+ has been changed to Ti3+ after UV irradiation. The crystal structure of the TiO2 in the SiO2-TiO2 film is mainly anatase as shown by XRD and the crystal grain size is about 14 similar to 20 nm. The AFM was used to study the morphology of the films annealed at different temperatures.