Spectroscopic studies of TeO₂-based glasses doped with Sm³⁺ and its use as an optical temperature sensor

Abstract

This study reports the synthesis and characterization of glasses in the (100-x) 65TeO2-15Li2O-20ZnO + x Sm2O3 system doped with Sm2O3, denoted as Sm3+: TLZ glasses, with varying doping concentrations from 0.1, 0.15, 0.2, 0.35, 0.5, and 1 mol%. The structural and optical properties, as well as the temperature dependence of luminescence, were investigated. Excitation at 405 nm resulted in strong orange-red luminescence at 566, 600, and 646 nm. The local environment surrounding Sm3+ ions was explored using the intensity ratio of electric and magnetic dipole transitions. The non-radiative energy transfer between neighboring Sm3+ ions was evaluated using the Inokuti-Hirayama model, allowing for the determination of the critical transfer distance. The temperature dependence of luminescence, displayed by Commission Internationale de L'Eclairage (CIE) chromaticity coordinates, exhibited a monotonic change from (0.611, 0.387) at 295 K to (0.605, 0.393) at 479 K. The Sm3+:TLZ glasses doped with 0.15 mol% showed the highest relative thermal sensitivity of 0.10%K-1 at 479 K, suggesting their potential as luminescent thermometers.