Local structure and photoluminescent characteristics of Eu3+ in ZnO-SiO2 glasses

The photoluminescence properties of xZnO-(100-x)SiO2 (x = 0, 5, 10, 20) containing 1% Eu2O3 prepared by a sol-gel method were systematically investigated. The results indicated that the relative proportion of f-f transitions to charge transfer (CT) absorption decreased with the increase of ZnO concentration. The intensity of D-5(0)-F-7(J) transitions of Eu3+ ions was enhanced with the increase of ZnO content due to local structure changes and decreased quantities of Eu3+ ions clusters. The results of fluorescence line narrow (FLN) spectra indicated that Eu3+ ions occupied one site in SiO2 glass and two sites in ZnO-SiO2 glasses. The second-order crystal field parameters were calculated. B-20 and B-22 for site 1 increased with excitation energy, while ones hardly changed for site 2.