Tunable emission and energy transfer of Tb3+/Eu3+ co-doped single-phase Sr2MgSi2O7 glass-ceramics

Abstract

In this work, the Tb³⁺/Eu³⁺ co-doped 30SrO–10MgO–50SiO₂–5TiO₂–5B₂O₃–1Tb₂O₃-xEu₂O₃ (x = 0–2.5 mol% at 0.5 intervals) glasses were prepared by the melt-quenching method, and the single-phase Sr₂MgSi₂O₇ glass-ceramics were obtained after heat treatment. The structural and fluorescence performance of the glasses and glass-ceramics were examined using DSC, XRD, SEM, FTIR, and photoluminescence spectra, and the energy transfer process between Tb³⁺ and Eu³⁺ was systematically investigated. With increasing Eu₂O₃ contents, the thermal stability of the glasses is enhanced and the density of both the glasses and the glass-ceramics rises. The XRD and SEM results reveal the precipitation of the irregular spherical Sr₂MgSi₂O₇ microcrystals with a grain size roughly within 0.5–1 μm. Under 376 nm excitation, the overall emission intensity and lifetime of Eu³⁺ ions increase with increasing Eu₂O₃ contents, and the energy transfer efficiency reaches 58.74 % from 31.07 %. According to the Dexter model, the energy transfer process between the Tb³⁺ and Eu³⁺ is dominated by the quadrupole-quadrupole interactions. By varying the Eu₂O₃ contents, all the glass-ceramics exhibit higher color purity (82.06–96.27 %), and their chromaticity coordinates shift from yellowish green towards reddish orange, which is potentially promising for w-LEDs.