Luminescence Dependence of Pr3+ Activated SiO2 Nanophosphor on Pr3+ Concentration, Temperature, and ZnO Incorporation

Green-emitting ZnO nanoparticles were successfully embedded in Pr3+- doped SiO2 by a sol-gel method resulting in a red-emitting ZnO center dot SiO2:Pr3+ nanocomposite phosphor. The particle morphology and luminescent properties of SiO2:Pr3+ phosphor powders, with or without ZnO nanoparticles, were, respectively, investigated by electron microscopy and luminescence spectroscopy. Luminescence of SiO2:Pr3+ was studied as a function of different Pr3+ concentrations and temperature. Both Pr3+ concentration and temperature were found to influence the D-1(2) emission from Pr3+ strongly. Defects emission from ZnO nanoparticles was measured at 517 nm compared with the normal peak at 470 nm from micrometer-sized ZnO powders. Only red emission at 614 rim from Pr3+ ions in SiO2:Pr3+ and ZnO center dot SiO2:Pr3+ was observed. The green emission from ZnO in ZnO center dot SiO2:Pr3+ was quenched, and the red emission from Pr3+ was doubly enhanced compared with SiO2:P3+. The enhancement of the PL intensity from SiO2:Pr3+ with ZnO incorporation denotes the presence of energy transfer from ZnO to Pr3+ ions.