Studies on photocatalytic activity and transmittance spectra of TiO₂ thin films prepared by r.f. magnetron sputtering method

Transparent TiO₂ thin films were obtained on microscope glass slides by r.f. magnetron reactive sputtering. The samples were investigated using X-ray diffraction (XRD), transmittance electron microscopy (TEM), UV-VIS-NIR spectrophotometer and coatings scratch testing. All the films were anatase phase and the particle size was in nanoscale. The photocatalytic properties of the samples were tested on the degradation of methylene blue dye solution. It was found that the photocatalytic activity increased with decreasing sputtering pressure. At the same time, the results indicate that the band gaps of the films all became larger than the bulk TiO₂ and the adhesion strength between the films and the substrates decreased with increasing sputtering pressure.