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 CaAl₂Si₂O₈ (CASO): Tb³⁺, Dy³⁺. With increasing concentration of Dy³⁺, a great enhancement of the blue PSL attributed to the defects and the transition of Tb³⁺ is observed. TL spectra indicates that the establishment of trap level introduced by codoping Dy³⁺ is the reason for the color variation between PSL and PL in CaAl₂Si₂O₈: Tb³⁺, Dy³⁺. The trap level not only serves as self‐excitation state but also hinders the nonradiative relaxation processes between ⁵D₃ and ⁵D₄ state of Tb³⁺. The result suggests that the introduction of appropriate trap level could provide a promising approach for controlling the color of electron trapping materials (ETMs).