Effect of Alkaline Earth Metals on Luminescence Characteristic in Eu-Doped Oxynitride Phosphate Glasses

Abstract In this article, a series of Eu-doped oxynitride phosphate glass samples are prepared. It is shown that the photoluminescence of Eu can be tuned through different alkaline earth metal ions (M2+). The luminous intensity of Eu2+ decreases with increasing ionic radius in the order of Mg＜Ca＜Sr＜Ba. And with the increased mismatch degree of radius between M2+ and Eu ions, the luminescence of Eu3+ gains intensity. The effects of M2+ on structure and luminescence characteristics of glass are mainly due to the following three factors: the field strength of M2+, the degree of mismatch between M2+ and Eu ions, and the influence of alkaline earth metals on the coordination tendency of N3- and O2- with Eu ions. The reduction mechanism is explained by combining the unequal substitution of Eu3+ ions for divalent alkaline earth metal cations with the reduction of Eu3+ by O2- and N3- ions. Our work provides a new perspective for studying the luminescence characteristics and mechanism of Eu ions in oxynitride Phosphate Glasses.