Color Variation Between PSL and PL in CaAl2Si2O8:Tb3+ with the Assistance of Trap Level

We reported a green photoluminescence ( PL ) emission associated with a blue photo‐stimulated luminescence ( PSL ) phenomenon in CaAl 2 Si 2 O 8 ( CASO ): Tb 3+ , Dy 3+ . With increasing concentration of Dy 3+ , a great enhancement of the blue PSL attributed to the defects and the transition of Tb 3+ is observed. TL spectra indicates that the establishment of trap level introduced by codoping Dy 3+ is the reason for the color variation between PSL and PL in CaAl 2 Si 2 O 8 : Tb 3+ , Dy 3+ . The trap level not only serves as self‐excitation state but also hinders the nonradiative relaxation processes between 5 D 3 and 5 D 4 state of Tb 3+ . The result suggests that the introduction of appropriate trap level could provide a promising approach for controlling the color of electron trapping materials ( ETM s).