ALD-induced TiO₂/Ag nanofilm for rapid surface photodynamic ion sterilization

The daily life of people in the intelligent age is inseparable from electronic device, and a number of bacteria on touch screens are increasingly threatening the health of users. Herein, a photocatalytic TiO₂/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction. Ultraviolet-visible (UV-Vis) spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO₂. The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO₂/Ag film against S. aureus and E. coli was 98.2% and 98.6%, under visible light irradiation for 5 min. The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO₂ reduced the bandgap of TiO₂ from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO₂ and Ag. Thus, TiO₂/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens. More importantly, the TiO₂/Ag film had great biocompatibility with/without light irradiation. The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.