Filling of trap and green long persistent luminescence in Sr3Al2O5Cl2:Tb3+

Abstract The Tb3+ doped Sr3Al2O5Cl2 phosphors have been synthesized via high temperature solid state reaction and their photoluminescence properties have been investigated. The Sr3Al2O5Cl2:Tb3+ samples emit a green luminescence from 5D4 to 7Fj (j = 6, 5, 4, 3) transition of Tb3+. The phosphorescence can be observed clearly by the naked eyes (0.32 mcd/m2) in the dark for over 1 h after 254 nm irradiation for the 5 min. Thermoluminescence (TL) measurements indicated that the TL glow curve was composed of the peaks located at 62, 142, 250 °C. The filling of traps was investigated by changing the irradiation time. Furthermore, the origin of long persistent luminescence has also been discussed.