Multifunctional ZnO nanorods decorated with plasmonic gold nanoparticles for enhanced room temperature field emission, photo-luminescence and catalytic properties

We report the enhancement of room temperature photoluminescence (PL), field emission and photocatalytic properties of ZnO nanorods (NRs) decorated by gold NPs (Au-ZnO NRs) prepared using hydrothermal process. The results of X-ray diffraction (XRD) analysis confirmed formation of gold NPs (NPs) and wurtzite phase of ZnO in the final nanostructures. Microscopic studies revealed that uniform ZnO NRs were formed and gold NPs are well decorated on the surface of the NRs. It was shown that both reaction time and concentration of HAuCl4 play a crucial role in photocatalytic, field emission and PL properties of Au-ZnO NRs. We suggest that there is a correlation between the shape of the NRs and concentration of HAuCl4 which causes the maximum PL intensity and stronger field emission properties. The ultraviolet (UV) and visible-light photocatalytic performance was successfully demonstrated for the photodegradation of Methylene blue (MB) as a model dye. Field emission studies revealed that by introducing gold NPs into the ZnO NRs the emission current increases. We have found that the shape of the nanostructure has a crucial role in the field emission properties and at higher reaction times, where the aspect ratio of the ZnO NRs decreases, the emission current also decreases.