Concentration effect and temperature quenching of upconversion luminescence in BaGd2ZnO5:Er3+/Yb3+ phosphor

Er3+/Yb3+ codoped zincate BaGd2ZnO5 phosphors were synthesized via a traditional solid state reaction. The crystal structure and phase purity were checked by means of X-ray diffraction (XRD), and the results showed that pure phase BaGd2ZnO5 phosphors with various Er3+, Yb3+ concentrations were obtained. The influence of Er3+ and Yb3+ doping concentrations on the green and red upconversion emissions was studied. It was found that both green and red upconversion emissions under 980 nm excitation were two-photon processes independent from the rare earth doping concentrations. However, the upconversion luminescence intensities greatly depended on the rare earth doping concentration. Furthermore, the population processes of upconversion luminescence and the quenching mechanisms were analyzed. The temperature-dependent green upconversion luminescence was studied, and the temperature quenching process of two green upconversion emissions was modeled. The thermal quenching processes of the green upconversion emissions could be well explained by the model we proposed.