Photoluminescence of ZnO nanoparticles prepared by a novel gel-template combustion process

ZnO nanoparticles have been synthesized by mean of a novel gel-template combustion method. The products were characterized by using TG-DTA, XRD and TEM techniques. The products appeared to be regularly spherical or elliptical and their sizes ranged from 20 to 30 nm.The average particle size increased with increasing sintering temperature. The photoluminescence spectra of the resulting ZnO nanoparticles showed a near-UV emission and a green emission. Furthermore, the dependence of the optical properties on the annealing temperatures and annealing time were also investigated. With the increase of the annealing temperature, the intensity of the green emission at 500 nm caused by oxygen vacancies in ZnO rapidly increased, but almost disappeared only at 600 °C.The probable mechanism was discussed.