Characteristics modification of TiO(2) thin films by doping with silica and alumina for self-cleaning application

Self-cleaning hydrophilic and hydrophobic properties of TiO(2)-based thin films on glass substrates have been investigated in this study. The addition of SiO(2) into TiO(2) can increase the wettability of films and maintain the hydrophilic state for a long time even in the dark. The contact angle of water on deposited films containing 15% SiO(2) is less than 2' after 2h of UV illumination. These TiO(2)-SiO(2) films exhibit excellent antifogging characteristics. Meanwhile, TiO(2)-Al(2)O(3) films possess high water repellent ability and the photo-induced self-cleaning can take place even in visible light. The TiO(2) thin film containing 33% of Al(2)O3 shows a high hydrophobic state with a water contact angle of 73' after being irradiated with sunlight for 2h. A comparison of hydrophilic TiO(2)-SiO(2) and hydrophobic TiO(2)-Al(2)O(3) films demonstrates the ability to modify the TiO(2) thin film properties for self-cleaning applications.