Preparation and properties of TiO2-SiO2 thin films by sol-gel process

We prepared TiO₂-SiO₂ thin films by sol-gel process and examined their optical, structural and photocatalytic properties as a function of film composition. The XRD results show that pure TiO₂ thin films are amorphous at 400°C, transform into anatase at 500°C, and further transform into rutile at 1000°C. The grain size of TiO₂ thin films increases with increasing calcination temperature. Refractive indices of the pure TiO ₂ and SiO₂ thin films are 2.10 and 1.40, respectively at 550 nm, and they decrease with increasing SiO₂ content in composite TiO₂-SiO₂ films. Photocatalytic activity of TiO₂-SiO₂ composite thin films decreases with increasing SiO₂ content