Influence of S doping on structural, optical and visible light photocatalytic activity of ZnO thin films

Pure and S doped ZnO thin films have been synthesized by hydrothermal method at 90 °C for 3 h. Powder XRD analysis shows the formation of hexagonal wurtzite phase of ZnO. The incorporation of S in ZnO lattice was confirmed by XPS analysis. FE-SEM results reveal that the synthesised thin films possess vertically aligned 1D rod structure with hexagonal morphology. UV–visible transmission spectral studies showed that the optical band gap of ZnO was reduced by S doping. PL spectrum confirmed that the effective S doping enhances the visible emission and suppresses the near band gap emission. The effect of S doping on the photocatalytic activity of ZnO thin films for the degradation of methylene blue dye was studied under visible light illumination and the results showed that the S doping provokes appreciable degradation of MB. Furthermore, the S doped ZnO film showed enhanced antibacterial activity compared to pure ZnO film against a Gram negative (Escherichia coli) and a Gram positive (Staphylococcus aureus) bacteria. This ensures that the S doped ZnO thin films can act as a UV blocking agent with enhanced photocatalytic and antibacterial activities.