Thermal, structural and optical behaviour of Eu³⁺ ions in Zinc Alumino Boro-Silicate glasses for bright red emissions

In present work we report the thermal, structural and optical behaviour of 20SiO₂-(20-x) B₂O₃–10Al₂O₃–10ZnO–30NaF–10ZnF₂-xEu₂O₃ glass system where Eu₂O₃ ions is doped in different molar concentrations (x = 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %). The Differential thermal analysis measurement was employed to study the thermal stability of the glasses through various thermal parameters such as Dietzel factor (ΔT), Hruby's parameter (K_H), Weinberg Parameter (K_W) and Lu and Liu Parameter (K_LL). FTIR studies exhibit the presence of BO₃, BO₄, SiO₂ vibrational units and the deconvoluted peak areas is used for the calculation of bridging and non-bridging oxygens. From the absorption spectra, the indirect bandgap energy (E_g) and Urbach's energy (E_U) of the glasses have been calculated. Judd-Ofelt (JO) intensity parameters (Ω₂ and Ω₆) have been evaluated from the emission spectrum. The radiative parameters such as radiative transition probability (A_R), branching ratio (β_R), stimulated emission cross-section (σ_se) and radiative lifetimes (τ_R) were obtained using the JO parameters for the transitions ⁵D₀→⁷F_1,2,4 of Eu³⁺ ions. The decay life time of the ⁵D₀ level is found to be single-exponential for all the Eu³⁺ doped glasses. An increase in lifetime values for the prepared glasses was found with increase in Eu³⁺ concentration from 0.1 mol% to 2.0 mol%. The colour chromaticity values and CCT values show the bright red emission from the prepared glasses.