Metal oxide composite thin films made by magnetron sputtering for bactericidal application

To broaden the application of antibacterial catalysts, ZnO/Ag2O composite thin films with different Ag2O contents have been successfully synthesized on non-woven fabric at room temperature by radio frequency (RF) sputtering with a single ceramic target formed by hot pressing ZnO/Ag2O nanocomposite powder in Ar atmosphere at 180 degrees C for 30 min. The composite thin films were also sputtered on glass substrates for characterizations. The best sputtering condition was found with the Ar/O-2 gas flow ratio at 7:1 to obtain pure Ag2O thin film. The deposition of nanoparticles on commercially available ZnO particles was also confirmed by HR-TEM prior to hot pressing for synthesizing ceramic targets. In this work, an appropriate amount of Ag2O incorporated in the composite film was endeavored by forming p-n junction to lower the cost without decreasing bactericidal ability of composite film. The amount of 45 wt % Ag2O in composite thin film to provide bactericidal effect was found to be as good as pure Ag2O. The feasibility in bactericide is due to the light sensitization of low bandgap Ag2O and the formation of nano p-n heterojunction between p-type Ag2O and n-type ZnO for efficient photo carrier separation. The dependence of antibacterial effect of ZnO/Ag2O thin films on the Ag2O content is demonstrated and elucidated in this work. (C) 2017 Elsevier B.V. All rights reserved.