Kinetics of fluorescence properties of Eu~(3+) ion in strontium-aluminiumbismuth-borate glasses

Eu³⁺ doped strontium-aluminium-bismuth-borate glasses with the chemical composition (50–x)B₂O₃+20Bi₂O₃+7AlF₃+ 8SrO+15SrF₂+xEu₂O₃ (where x=0.1 mol.%, 0.5 mol.%, 1.0 mol.% and 1.5 mol.%) were prepared by the conventional melt quenching technique. Structural properties of the prepared glasses were analysed through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Raman spectral techniques. Thermal stability of glass was analysed by differential thermal analysis (DTA) curve. Photoluminescence characteristics were studied using excitation, emission spectra and decay curves of Eu³⁺ doped strontium-aluminium-bismuth-borate glasses. The Judd-Ofelt (J-O) intensity parameters, Ω_λ (λ=2, 4 and 6) were obtained using emission spectra and was used to identify the nature of Eu³⁺ ions with their surrounding ligands. Using J-O parameters the transition probabilities (A), stimulated emission cross-sections σE p, branching ratios (β_R) and radiative lifetimes (τ_meas and τ_cal) were evaluated for the ⁵D₀→⁷F_J (J=0, 1, 2, 3 and 4) transition of Eu³⁺ ions in the present glasses. The decay profiles were found to be non exponential for all the concentrations and the measured lifetimes (τ_meas) were obtained from the decay profiles. The higher values of A, σE p, β_R and quantum efficiency (η) for ⁵D₀→⁷F₂ emission transition at 617 nm confirmed the present glass was as active medium for red laser emission applications.