UV light and X-ray induced luminescence properties of Eu3+ and Tb3+ single-doped and double-doped phosphosilicate glasses for LED and scintillator applications

Eu³⁺ and Tb³⁺ single-doped and co-doped phosposilicate (P₂O₅ +SiO₂) glasses with the insertion of fluorides (NaF+BaF₂+AlF₃) were fabricated. Absorption and excitation spectra of glasses were studied. With two different (218 and 378 nm) excitations of Eu³⁺ and Tb³⁺, the visible emission spectra (450˗750 nm) consisting of RGB (red-green-blue) colors were obtained. The multipolar interactions involved in the energy transfer (ET) between Eu³⁺ and Tb³⁺ were analyzed through Reisfeld and Dexter's theory. The lifetimes of the co-doped glasses for the ⁵D₀ emission (λ_ex=378 nm) of Eu³⁺ and the ⁵D₄ emission (λ_ex=218 nm) of Tb³⁺ ions were obtained. Further, the asymmetric ratios, integrated intensities, R/G ratios, and ET efficiencies were also evaluated. The scintillation efficiency of glasses determined from radio luminescence (X-ray) was found to be 62%. The color coordinates of the glasses were moved to yellowish-green zone with the CCT (correlative color temperatures) of ≤ 4037 K.