Energy transfer phenomenon of Gd to excited ground state of Eu ions in LiO-BaO-GdO-SiO-EuO glasses.

LiO-BaO-GdO-SiO glasses with different concentration of Eu 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 which is attributed to Si-O-Si symmetric stretching mode. Density and molar volume of LBGSEu glasses increases with Eu ions concentration. The covalent nature of bond between the Eu 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, Eu ions have asymmetric coordination environment and stronger covalency. The phonon line PSB (22,522 cm) confirm the phonon energy ≈971 cm, that corresponds to the energy of one phonon associated with maximum energy of the vibrational mode couple to Eu ions. Under 275 nm and 393 nm excitation, intense red emission was observed at 613 nm, we observe efficient energy transfer phenomena from Gd → Eu in these glasses. Increasing trend of I with increasing concentration of EuO indicates the asymmetric environment around Eu 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 EuO 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.