X-ray excited optical luminescence changes induced by excess/deficiency lithium ions in rare earth doped LiAl5O8

Cerium, terbium and europium doped LiAl5O8 phorphors with different lithium concentrations (deficiency and excess) are synthesized by the sol-gel method using glucose. The effect of lithium concentration on the X-ray excited optical luminescence (XEOL) properties are investigated in detail. The XEOL intensity of the peaks change directly with Li concentration. For Ce and Eu doped samples, the rare earth emissions are more intensity in the stoichiometry structure. In contrast, the most intense Tb emissions are found in the sample with excess Li. In all doped samples, the XEOL integral exhibits a positive edge jump. This indicates that the X-ray energy is preferentially absorbed by the local dopant site and is effectively transferred to the optical channel(s).