Luminescence properties of europium doped oxyfluorosilicate glasses for visible light devices

Abstract

Europium (Eu3+)-doped oxyfluorosiliacte (SALfSfEu: SiO2 + Al2O3 + LiF + SrF2 + Eu2O3) glasses have been fabricated by usual melt-quenching technique. These glasses were characterized through optical absorption, excitation, emission and decay curve analysis. The Judd-Ofelt (JO) parameters have been evaluated from the refractive index and luminescence spectrum of the 1.0 mol% Eu3+-doped glass. The quantitative radiative properties including branching ratio, radiative lifetime and stimulated emission cross-sections of the fluorescent levels were predicted by using the JO parameters. Luminescence intensity increases as for as 0.5 mol% and then decreases with further increasing Eu3+ ion concentration. Photoluminescence quantum yield found to be as high as 74% for 0.05 mol% of Eu3+ ion concentration and decreased by increasing concentration. Luminescence intensity ratio is found to be 3.17 for 1.0 mol% Eu3+-doped SALfSfEu1.0 glass which suggest that the occupation of high degree of symmetry by the Eu3+ ions. Fluorescent decay curves of the emitting level exhibit an exponential behaviour. Lifetime of 5D0→7F2 transition was decreased slightly with increasing Eu3+ ion concentration, however, not significant for 5D1→7F1 transition. Luminescence properties reveal that the red emission at 612 nm found to be suitable for developing the lasers and display devices in the visible region.