Publication

Abstract : Herein, we present the structural, optical, and luminescence attributes of Tb3+-doped Li2O–CaO–Bi2O3–B2O3 glasses using the melt-quenching method, focusing on the effects of Tb3+ incorporation. XRD confirmed their amorphous nature, with density and refractive index increasing alongside Tb3+ concentration, indicating a denser glass network and significantly enhanced optical polarizability. FTIR spectral analysis reveals that Tb3+ ions functioned as network modifiers, changing the strength of B-O bonds and causing the formation of NBOs inside the borate network. The absorption spectra showed distinct 4f–4f transitions, particularly a strong absorption band at 481 nm related to the 7F6 → 5D4 transition. The PL spectra exhibited strong green emission, with the main peak at 543 nm (5D4 → 7F5) and additional emissions at 488 nm, 412 nm, and 436 nm. The luminescence intensity peaked at 0.75 mol% Tb3+, after which concentration quenching occurred. Lifetime measurements decreased from 2.07 ms at 0.25 mol% to 1.23 ms at 1 mol% Tb3+. JO analysis indicated ionic bonding of Tb3+ in the glass, demonstrating the Ω6 > Ω4 > Ω2 (with Ω6 being the highest). The optimized 0.75 mol% Tb3+-doped glass demonstrated thermal stability up to 600 °C, a gain coefficient of 3.19 cm−1, quantum efficiency of 65 %, and a radiative lifetime of 2.31 ms, along with a maximum absorption cross-section of 4.055 × 10−22 cm2 and an emission cross-section of 7.141 × 10−22 cm2. These findings highlight that with strong green emission at 543 nm and efficient UV excitation (376 nm), Tb3+-doped Li2O–CaO–Bi2O3–B2O3 glasses are promising candidates for high-power green lasers and advanced photonic devices.