Antibacterial performance of photocatalyst thin film fabricated by defection effect in visible light

We have developed a new photocatalyst thin film that has strong antibacterial action in visible light. In this study the radiofrequency (RF) sputter technique was used to deposit a defective titanium dioxide (TiOx, x < 2) photocatalyst thin film (120 nm thickness) on glass and steel substrates. In the ultraviolet (UV)-visible spectrum analysis, the defective TiOx thin film was found to generate the red shift effect. To determine whether the defective TiOx thin film has antibacterial ability under visible light, we designed a series of experiments according to the Japanese Industrial Standards (JIS) Committee standard for testing antibacterial performance and for exploring the impact of surface roughness of substrate. Our results show that the antibacterial performance rate against Escherichia coli could reach 99.99% in visible light. We also proved that the coating technology can be applied effectively to surfaces with different degrees of roughness. It is suitable for protecting both human health and the natural environment.