High-quantum-efficiency Eu3+–doped TeO2–B2O3–PbO glasses for non-contact optical temperature sensing excited by 405 nm laser

We report the synthesis and comprehensive optical characterization of a high TeO 2 concentration lead boro-tellurite (TBP) glass with composition 70TeO 2 –20B 2 O 3 –10PbO doped with different concentrations (0.5–2.0 mol %) of Eu 3+ ions. The Eu 3+ -doped TBP glasses exhibit high optical transparency, enhanced structural stability, and intense red photoluminescence under low-power 405 nm laser excitation (10 mW), with emission quantum efficiencies up to 80.3 %. Judd–Ofelt analysis and decay time measurements confirm the efficient radiative properties of the Eu 3+ ions in this glass matrix. A high-performance non-contact optical thermometry system was developed using the temperature-dependent luminescence intensity ratio ( LIR ) between the 5 D 0 → 7 F 2 (613nm) and 5 D 0 →7F 1 (592 nm) transitions and a valley at 602 nm, allowing for accurate temperature readout from 18 to 298 °C (291 to 571 K). The Eu 3+ -doped TBP glasses exhibited excellent reversibility, thermal stability, and sensitivity, with best thermometric response for the sample TBP:2.0Eu 3+ with maximum relative sensitivity of 0.89 % K -1 and temperature resolution as low as 0.26 K at 571 K. These results position Eu 3+ -doped TBP glasses as promising candidates for robust, low-cost, and high-resolution optical thermometric applications in harsh environments. • 0.7TeO 2 -0.2B 2 O 3 -0.1PbO (TBP) glasses were prepared with 0.5, 1.0 and 2.0% of Eu 3+ . • Optical and structural properties of Eu 3+ –doped TBP glasses were determined. • Quantum efficiencies of 76.9 up to 80.3% were obtained for Eu 3+ –doped TBP glasses. • Optical thermometry was measured with high sensitivity and reversibility. • The luminescence has robust and repeatable response over 18–298 °C temperature range.