Physical and photoluminescence investigations of Eu³⁺ doped gadolinium borate scintillating glass

The bright reddish-orange emitting Eu³⁺-doped gadolinium borate glasses of 25Gd₂O₃-(75-x) B₂O₃-xEu₂O₃ (GdBEu) (x = 0.1, 0.3, 0.5, 1.0, 3.0, 5.0, 7.0, and 9.0 mol%) were fabricated by melt-quenching technique at 1400 °C for 3 h. All GdBEu glasses were investigated the photoluminescence, scintillation, and lasing potential properties. The energy transfer processes from Gd³⁺→Eu³⁺ in these glasses were discovered. Photons in the ultraviolet, visible, and near-infrared region wavelengths were absorbed by glasses. The photoluminescence excitations were performed at 275 nm and 394 nm, respectively. When the energy transferred from Gd³⁺ to Eu³⁺, luminescence features revealed an intense red emission with a wavelength of 614 nm (⁵D₀ → ⁷F₂). The glass's optimum Eu³⁺ ion concentration was 7.0 mol%, corresponding to the maximum emission intensity. Judd-Ofelt parameters were calculated from the emission spectra and the radiative properties of several excited states were examined, including the transition probability (A_R), branching ratio (β_R), stimulated emission cross-section (σ_e), and decay time (τ_R). Once the Eu³⁺ concentration increased from 0.1 to 9.0 mol%, the decay time of the ⁵D₀ level dropped from 1.824 ms to 1.585 ms. The colors of glasses were confirmed by the Commission internationale de l'éclairage (CIE) chromaticity diagram. The glass samples had a peak area of radioluminescence (RL) spectrum 18% of BGO scintilltation crystal.