Persistent luminescence from Y3Al2Ga3O12 doped with Ce3+ and Cr3+ after X-ray and blue light irradiation

The persistent luminescence (PersL) dependence on the dopants and derived mechanism of trapping and de-trapping processes were investigated in Y3Al2Ga3O12 (YAGG) based nanophosphor, doped with Ce3+ and/or Cr3+. It is found that the presence of Cr3+ ions produce electron and hole traps and capture suitable charge after X-ray irradiation. The effect of irradiation on the carriers trapping and their pathways after excitation was studied by means of thermo luminescence technique. On the other hand, for blue light irradiation the mechanism seems to be different. In the latter case, the Ce3+ ions, having the position of energy levels in the conduction band, become sensitizers for the electrons and main emission centres for the PersL (de-trapping process goes through Ce3+).