Characterization of sputtered triple layer photoactive coating with a glass-like appearance

摘要

Photocatalytic activity of sputtered TiO_2 single layer was investigated. From the results on the optical constants analyses and dark- and photoconductivity measurements, it is revealed that the photocatalytic activities of TiO_2 films depend on the defect density of the TiO_2 films; the atomic defects act as recombination sites for photo-generated carriers diffusing to the TiO_2 surface. A three-layer system with a layer construction of SnO_2/TiO2/Si_3N_4/Glass was designed for realizing the glass-like appearance, namely almost the same transmission and reflection spectra in visible wavelength region as those of glass, and its photocatalytic activity was investigated. The experimental results indicate that the interface between TiO_2 and SnO_2 acts as a potential barrier for the carriers photo-generated in the TiO_2 and the photo-generated species pass through the SnO_2 overlayer depending on the SnO_2 film characteristics.