Surface morphology, electrochemical and electrical performances of ZnO thin films sensitized with Ag nanoparticles by UV irradiation

Abstract

Pure zinc oxide and Ag/ZnO thin films were prepared via two step method. The crystal structure, topography, chemical composition and optical properties were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) spectrophotometer and laser micro-Raman spectrometer. XRD, FE-SEM and XPS results indicated that Ag nanoparticles were successfully deposited on the zinc oxide nanorods. Ag nanoparticles on the zinc oxide nanorods would extend the photoabsorption region and reduce the electron transition from CB to VB. The photoelectrochemical performances of ZnO thin film could be effectively enhanced by moderate Ag nanoparticles modification. Under sunlight illumination, the photocurrent of the Ag-0.5/ZnO electrode was about three times as large as that of the zinc oxide electrode. The charge transfer process for the Ag/ZnO electrode under sunlight illumination has been discussed. With the increase of Ag content, the resistivity of the sample decreases sharply.