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 degrees 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. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.