Energy transfer to Gd3+ from the self-trapped exciton in ScPO4:Gd3+ — In the case of persistent luminescence

We report a persistent luminescence phenomenon of ScPO 4 :Gd 3+ phosphor, which exhibits long-lasting ultraviolet emission peaking at 313 nm after the end of X-ray irradiation. Unlike the steady-state luminescence of the phosphor excited by ionizing irradiation, no quantum-cutting emission is involved in the persistent luminescence. We ascribe the presence of persistent luminescence, as well as the absence of quantum cutting, to the effect of self-trapped exciton on the electron and energy transfers. This work provides some insights to the understanding of Gd 3+ -activated ultraviolet persistent luminescence. • Ultraviolet persistent luminescence of ScPO 4 :Gd 3+ phosphor. • Persistent energy transfer from the self-trapped exciton (STE) to Gd 3+ . • No quantum-cutting emission is involved in the persistent luminescence.