Development of Eu³⁺ doped Li₂O-BaO-GdF₃-SiO₂ oxyfluoride glass for efficient energy transfer from Gd³⁺ to Eu³⁺ in red emission solid state device application

The Eu³⁺- doped Li₂O-BaO-GdF₃-SiO₂ glasses were fabricated by conventional melt quenching technique to study its spectroscopic and luminescence properties for lasing potential. The density and molar volume of the glass had been increased with Eu₂O₃ concentration. An FTIR spectrum is used to study the structural properties of the developed glasses. Two intense peaks were observed in UV–Vis–NIR spectra at 2206 nm (⁷F₆) and 2085 nm (⁷F₁) in NIR region. Under 394 nm excitation LBGFS display five regular emission peaks at (578 nm) ⁷F₀, (590 nm) ⁷F₁, (613 nm) ⁷F₂, (651 nm) ⁷F₃ and (701 nm) ⁷F₄ from ⁵D₀ state, the most intense red emission was found at 613 nm. The characteristic intense red emission peak at 613 nm corresponding to the ⁵D₀ →⁷F₂ transition of Eu³⁺ ions has been observed for oxy-fluoride glass samples. Efficient energy transfer phenomena from Gd³⁺ → Eu³⁺ were observed under 275 nm excitation in these glasses. FTIR measurements reveal that these glasses show non-bridging oxygen stretching of Si-O^- at ~929 cm⁻¹. Phonon sideband spectrum confirms the phonon energy ~920 cm⁻¹ for these glasses arising from Si-O^-. Increasing trend of I_R/O with increasing concentration of Eu₂O₃ indicates the asymmetric environment around Eu³⁺ in LBGFS. Higher value of stimulated cross section (σ(λ_p)) branching ratio (β_R) for transition to ⁷F₀ from ⁵D₀ were observed for LBGFS glasses. Decay time decrease with increasing concentration of Eu₂O₃.