Synthesis and luminescence properties of a novel yellowish-pink emissive long persistent luminescence phosphor Cd2GeO4:Pr3+

Pr3+-doped Cd2GeO4 phosphors were synthesized successfully via a traditional high temperature solid-state reaction method. It showed yellowish-pink long persistent luminescence (LPL) after the short UV-irradiation. The optimal doping concentration of Pr3+ ions for the brightest photoluminescence (PL) emission and the best LPL performance were experimentally to be about 1.5% and 1 mol%, respectively. The suitable trap depth for the generation of LPL was determined to be about 0.65 eV. Based on TL measurements, the trapping and re-trapping processes of charge carriers were studied. A model was proposed on the basis of experimental results to explain the mechanisms of PL and LPL.