The antibacterial and hydrophilic properties of silver-doped TiO2 thin films using sol–gel method

Ag–TiO2 composite thin films were deposited on glass slides by sol–gel spin coating technique. The surface structure, chemical components and transmittance spectra were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis spectrophotometer. The TiO2 thin films with silver molar ratio from 0 to 10% were tested for its antibacterial property by using Escherichia coliform (E. coli) under irradiation of UV light. The concentration of E. coli was evaluated by plating technique. The influences of different molar ratio of Ag on hydrophilicity and long-term durability of the films were also investigated by measuring the water contact angle. The results showed that the antibacterial ability was significantly improved by increasing silver content comparing with pure TiO2 thin film, and the best molar ratio of Ag was 5%. While the hydrophilicity of films increased with increasing silver content, and the best molar ratio of Ag was 1%.