An intense ultraviolet photoluminescence in sol–gel ZnO–SiO₂ nanocomposites

We report the phenomenon that the intensity of the ultraviolet (UV) photoluminescence (PL) from ZnO was greatly enhanced by incorporating ZnO into the SiO₂ matrix. PL excitation results show that both the ZnO nanoparticles and the SiO₂ matrix in the nanocomposites contribute to the luminescence process for the UV band. On the basis of the x-ray photoelectron spectra, we suggest that interface energy states are formed due to the presence of Zn–O–Si bonds between ZnO nanoparticles and the SiO₂ matrix. A tentative model concerning the contribution of the ZnO nanoparticles, SiO₂ matrix, and ZnO–SiO₂ interface is suggested to explain the PL enhancement effect.