Wide band long persistent luminescence of Ca3Ga2Ge3O12 : Tb3+, Tm3+ phosphor with synergistic effect of different traps

The as-prepared Ca3-x-yGa2Ge3O12 (CGGO): xTb(3+), yTm(3+) phosphors exhibit a color-tunable long persistent luminescence (LPL) after the near-ultraviolet irradiation. Our results indicate that the shallow traps act as not only the trapping centers but also the bridge that contributes to the release of the carriers from deeper traps at room-temperature (RT), improving the LPL properties significantly. Moreover, the CGGO: xTb(3+), yTm(3+) phosphors exhibit an advantageous LPL performance at high-temperature because of the existence of deeper defect states.