Optical properties of TiO2 thin films after Ag ion implantation

Metal plasma ion implantation has being successfully developed for improving the electronic and optical properties of semiconductor materials. Prior to deposition, a TiO2 colloidal suspension was synthesized by microwave-induced thermal hydrolysis of the titanium tetrachloride aqueous solution. The TiO2 thin film was optimized to obtain a high-purity crystalline anatase phase by calcinations at 550 °C. The TiO2 coating was uniform without aggregation, which provided good photo conversion efficiency. Ag ion implantation into the as-calcined TiO2 thin films was conducted with 1 × 1015 ~ 1 × 1016 ions/cm2 at 40 keV. The peak position and intensity of the photoluminescence and UV–Vis absorption spectra are quite sensitive to Ag doping. The optical characterization showed a shift in optical absorption wavelength towards infrared ray side, which was correlated with the structure variation of the Ag+ implanted TiO2. Due to the strong capability of forming compounds between the energetic silver ions and TiO2, the photoluminescence emission and UV–Vis absorption efficiencies were improved.