Energy transfer phenomenon of Gd³⁺ to excited ground state of Eu³⁺ ions in Li₂O-BaO-Gd₂O₃-SiO₂-Eu₂O₃ glasses

Li₂O-BaO-Gd₂O₃-SiO₂ glasses with different concentration of Eu³⁺ ions were developed by the traditional melt quenching technique and characterized via FTIR, absorption, excitation, emission and CIE color coordinates analysis for visible red emission application. The FTIR shows strong band at position 740 cm⁻¹ which is attributed to Si-O-Si symmetric stretching mode. Density and molar volume of LBGSEu glasses increases with Eu³⁺ ions concentration. The covalent nature of bond between the Eu³⁺ ions and surrounding ligands was confirmed from the bonding parameter (δ). From absorption spectra JO-parameters and oscillator strength are evaluated for LBGSEu6 glass. From JO-parameters, Eu³⁺ ions have asymmetric coordination environment and stronger covalency. The phonon line PSB (22,522 cm⁻¹) confirm the phonon energy ≈971 cm⁻¹, that corresponds to the energy of one phonon associated with maximum energy of the vibrational mode couple to Eu³⁺ ions. Under 275 nm and 393 nm excitation, intense red emission was observed at 613 nm, we observe efficient energy transfer phenomena from Gd³⁺ → Eu³⁺ in these glasses. Increasing trend of I_R with increasing concentration of Eu₂O₃ indicates the asymmetric environment around Eu³⁺ ions in LBGS. Moreover, from JO analysis, LBGS glasses have high capability for red laser device with high lasing power and energy extraction ratio. The fluorescence lifetimes show decreasing trend in lifetime with increasing concentration of Eu₂O₃ is due to radiative transition. From CIE color coordinate, the CIE color coordinates of LBGSEu6 glass fall in reddish region close to orange region and can be useful for optical display devices.