Optical and luminescence characteristics of Eu³⁺-doped B₂O₃:SiO₂:Y₂O₃:CaO glasses for visible red laser and scintillation material applications

Europium (Eu³⁺) doped glasses of chemical compositions (55−x)B₂O₃:10SiO₂:25Y₂O₃:10CaO:xEu₂O₃, where x denotes mol% and ranges 0 ≤ x ≤ 2.5, were synthesized by adopting conventional melt quenching technique. Physical properties like density, molar volume, polaron radius, inter-ionic distance and field strength of the glass samples were investigated to assess the impact of Eu₂O₃. Optical and luminescence properties of the glasses were characterized with optical absorption, photoluminescence, X-ray induced emission spectra, temperature dependence emission spectra and decay times. Judd-Ofelt (JO) intensity parameters (Ω_λ) of the glasses were evaluated based on the absorption spectrum of 0.5 mol%. JO parameters, calculated from absorption spectra with thermal corrections on oscillator strength, were used to evaluate radiative properties such as radiative transition probability (A_R), branching ratio (β_R), stimulated cross section emission (σ) and radiative lifetime (τ_R) for ⁵D₀ → ⁷F_J (J = 0,1,2,3 and 4) transitions. The decay rate of ⁵D₀ fluorescent level for all the glass samples was single exponential. Lifetimes of the ⁵D₀ level were decreased with increasing concentrations of Eu³⁺ions from 0.05 mol% to 2.5 mol% which might be due to energy transfer through cross-relaxation in the glasses. The chromaticity coordinates (x, y) were similar for all BSYCaEu glasses and were located at the red region of CIE 1931 color chromaticity diagram. Hence, these results confirm that the Eu³⁺ doped BSYCaEu glasses could be useful for visible red lasers and glass scintillation applications.