Long afterglow properties of the blue emission from Pr3+-activated Sr5Ta4O15 phosphor

In this study, a novel blue emitting long afterglow (LAG) material based on Pr3+-doped Sr5Ta4O15 was prepared successfully using a conventional solid-state reaction method. The photoluminescence spectra, excited-state decay curve, LAG decay curve, and thermoluminescence glow curve were obtained to investigate the properities of Sr5Ta4O15:Pr3+ systematically. The blue LAG emission from Pr3+ was observed after excitation with a 254-nm ultraviolet lamp. The optimal doping concentration of Pr3+ for the best LAG performance was experimentally determined to be approximately 4 mol%. Based on the experimental results, a possible model was constructed to illustrate the mechanism of LAG in detail.