Photo generated charge transport studies of defects-induced shuttlecock-shaped ZnO/Ag hybrid nanostructures

Abstract

We report the stimulating effects of interfacial charge transfer process between spherical Ag nanoparticles and shuttlecock-shaped ZnO nanostructures observed by UV−visible spectroscopy and x-ray absorption spectroscopy. In specific, ZnO nanorods and shuttlecock-shaped ZnO/Ag nanostructures were developed using a simple chemical colloidal method and characterized for structural variations using XRD. The observed red shift in plasmonic peak and the increase in Urbach energy signify interfacial interactions and increased randomness in the hybrid ZnO/Ag nanostructures. Simultaneously, the enhanced intensity of deep-level emission in the ZnO/Ag hybrid suggests the increased recombination rate of electron-hole pairs. The red and blue emissions evolving with temperature subsequently suggests the presence of oxygen vacancies or zinc interstitials in the system. The decrease in intensities and emerging features in O K-edge and Zn L-edge indicates the charge transfer from Ag to ZnO at the interface of ZnO/Ag hybrids. Moreover, the differences in absorption edges with alternating light on/off conditions were analyzed for the exploitation of this ZnO-based system in various applications.

Probing size-dependent defects in zinc oxide using synchrotron techniques: impact on photocatalytic efficiency

“…The absorbance spectra obtained was used to calculate the degradation efficiency of the photocatalyst for the dye solution using the formula:where C 0 is the initial dye concentration and C t is the concentration of the dye in the supernatant solution after time t . 28,29 A schematic of the homemade photocatalytic setup used in the study is shown in Fig. 1.…”

“…where C 0 is the initial dye concentration and C t is the concentration of the dye in the supernatant solution after time t. 28,29 A schematic of the homemade photocatalytic setup used in the study is shown in Fig. 1.…”

“…[70][71][72] The enhanced photocatalytic activity observed for catalyst M-ZnO can be attributed partly to higher adsorption and partly to the electron-hole transportation. 28,70 The delayed recombination of excited electrons with the holes plays an important role in the faster degradation of the Rh-B test dye. This delayed recombination, as previously observed, could be due to transfer of charge to defect states.…”