Development of Orange-Emitting Sm2O3-Doped Tellurite Glasses Prepared for Solid State Lighting

A series of glass samples, with base composition of (40-x) TeO₂: 30B₂O₃: 20ZnO: 10Li₂O, was modified by incorporating varying concentrations of Sm₂O₃ (x = 0.00, 0.10, 0.50, 1.00, 1.50, and 2.00 mol%). X-ray diffraction analysis confirmed the amorphous nature of the prepared glasses. FTIR spectroscopy was used to investigate the structural arrangement of the glasses, revealing characteristic vibrational bands associated with Te-O, B-O, and Zn-O bonds. These bands provided insights into the glass network's evolution with changing Sm₂O₃ content. The optical properties of the glasses were investigated through absorption and photoluminescence studies. Absorption spectra, measured in the 400-1800 nm range, displayed seven peaks attributed to electronic transitions within the Sm³⁺ ion. These transitions originated from the ⁶H_5/2 ground state to various excited states. Photoluminescence analysis, excited at 403 nm, revealed a strong emission band centered at 597 nm. This emission corresponded to the ⁴G_5/2 → ⁶H_7/2 transition of Sm³⁺, responsible for the characteristic orange luminescence. The emission intensity increased with increasing Sm₂O₃ concentration up to 1.00 mol%, after which concentration quenching led to a decrease in intensity. In conclusion, this study elucidates the composition-structure-property relationships in Sm₂O₃-doped TeO₂-B₂O₃-ZnO-Li₂O glasses. The tunable orange emission suggests their potential as phosphors for solid-state lighting applications, particularly in orange LEDs.