The Lattice Defects of Nanofilm Introduced by N Doping Promotes Radical Oxygen Species Production for Rapid Photocatalytic Elimination of Contact Infection

Contact infection is accelerating the spread of pathogenic bacteria, threatening the health of people all over the world. Herein, photoresponsive TiO₂/N-doped ZnO (TiO₂/N-ZnO) nanofilms are synthesized using atomic layer deposition and the sol–gel method to rapidly kill bacteria on electronic touch screens by strengthened photocatalytic sterilization. The enhancement of the photocatalytic performance of TiO₂/ZnO is significantly attributed to the oxygen vacancy and crystal defect induced by nitrogen element doping, leading to the production of an increased quantity of reactive oxygen species from TiO₂/N-ZnO. Further, when bacteria engage with the nanofilm, there is an occurrence of electron transfer between the TiO₂/N-ZnO and the bacterial film, thereby consequently disturbing the electron equilibrium on the bacterial film. Upon exposure to simulated sunlight for a duration of 3 min (for Staphylococcus aureus; S. aureus) or 10 min (for Escherichia coli; E. coli), TiO₂/N-ZnO demonstrates superior antibacterial effects (>95%) on both bacterial strains. With the illumination time extended to 20 min, the antibacterial efficacy of TiO₂/N-ZnO against S. aureus and E. coli reaches up to 100%. Concurrently, the TiO₂/N-ZnO nanofilms demonstrate commendable light transmittance (>85%) and biocompatibility. As such, this study may offer a potential methodology for antimicrobial applications in electronic touch screens.