Luminescent Properties and Energy Transfer Mechanism of Gd3+ and Eu2+ Co-doped Phosphate Glasses

Abstract

The phosphate glasses doped with Eu2+, Gd3+, respectively, and co-doped with Gd3+ and Eu2+ were prepared by high-temperature melting method. The transmission spectra, the excitation spectra, the emission spectra and the fluorescent decay time were investigated. The energy transfer process between Gd3+ and Eu2+ was studied. From the excitation spectra and the emission spectra of the phosphate glasses doped with Eu2+, we observed that the emission intensity of Eu2+ shows higher for 0.02 mol% Eu2+-doped phosphate glass. According to the excitation spectra and the emission spectra and the fluorescence decay curves, when the concentration of Eu2+ was 0.02 mol%, the optimal concentration of Gd3+ was 0.3 mol%. Based on Dexter theory, it is shown that the energy transfer between Gd3+ and Eu2+ was nonradiation energy transfer by analyzing the energy-level diagram. The fluorescence decay curves of Gd3+ were expressed by the Inokuti–Hirayama’s model and were used to analyze energy transfer mechanism between Gd3+ and Eu2+. And the energy transfer efficiency was also calculated.