Sensitizing effects of ZnO quantum dots on red-emitting Pr3+-doped SiO2 phosphor

In this study, red cathodoluminescence (CL) (λemission=614 nm) was observed from Pr3+ ions in a glassy (amorphous) SiO2 host. This emission was enhanced considerably when ZnO quantum dots (QDs) were incorporated in the SiO2:Pr3+ suggesting that the ZnO QDs transferred excitation energy to Pr3+ ions. That is, ZnO QDs acted to sensitize the Pr3+ emission. The sol–gel method was used to prepare ZnO–SiO2:Pr3+ phosphors with different molar ratios of Zn to Si. The effects of the ZnO QDs concentration and the possible mechanisms of energy transfer from ZnO to Pr3+ are discussed. In addition, the electronic states and the chemical composition of the ZnO–SiO2:Pr3+ phosphors were analyzed using X-ray photoelectron spectroscopy (XPS).