Structure, optical properties and energy transfer in potassium-alumino-borotellurite glasses doped with Eu3+ ions

Highlights: • A series of Eu³⁺ doped B₂O₃-TeO₂-Al₂O₃-K₂O glasses were prepared by melt method. • The raise of B₂O₃ content decreases ligand symmetry and rigidity of glass network. • The optical parameters were analyzed by Judd-Ofelt theory and Inokuti-Hirayama model. • The best optical parameters are found for 50B₂O₃·30TeO₂·10Al₂O₃·10K₂O·4Eu₂O₃ sample. • The dominant interaction mechanism and cross-relaxation channels have been shown. -- Abstract: KABxTyE (xB₂O₃+yTeO₂ +10K₂O+10Al₂O₃ +0.5Eu₂O₃) glasses with the variation of B₂O₃/TeO₂ ratios (x/y = 30/50, 40/40 and 50/30) and KABTzEu glasses ((50-z)B₂O₃+30TeO₂+10Al₂O₃+10K₂O + zEu₂O₃, with z = 0.1, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 mol%) were prepared by melt–quenching technique. The structure of glasses was analyzed through X-ray diffraction (XRD) patterns, Fourier-transform infrared spectroscopy (FTIR) and phonon-sideband (PSB) spectra. The Judd-Ofelt (JO) theory was used to estimate the properties of ligand and the radiative parameters of prepared glasses such as lifetime (τ_cal), effective line width (Δλ_eff), stimulated emission cross-section (σ_P), gain bandwidth (σ_P × Δλ_eff), optical gain (σ_P × τ_cal) and quantum efficiency (η). The influence of B₂O₃/TeO₂ ratio and Eu³⁺ concentration on structure and optical properties of materials was discussed in detail. Energy transfer process between Eu³⁺ ions was studied by using Inokuti-Hirayama and Yokota-Tamimoto models. The energy transfer channels between Eu³⁺ ions were also proposed.