“…Persistent luminescence has been detected in various garnet hosts predominantly consisting of gallates and germanates: Y3(Ga,Al)5O12 [18,19], Gd3(Ga,Al)5O12 [20,21], Mg3Y2Ge3O12 [9,22] Y3Sc2(Ga,Al)3O12 [21], Lu3(Ga,Al)5O12 [23,24], Gd3Sc2Ga3O12, Lu3Sc2Ga3O12 [24] Na2CaSn2Ge3O12 [25,26], Na2CaTi2Ge3O12 [26] Ca3Ga2Ge3O12 [27] and others. The mechanism of persistent luminescence in garnets is mainly speculated to be related to recombination of intrinsic electron and hole centres [25,28] or impurity related charge centres [24,26].…”