Investigation of the optical temperature sensing properties of up-converting TeO₂-ZnO-BaO activated with Yb³⁺/Tm³⁺ glasses

Three different tellurite-zinc-barium-based glasses including Yb³⁺ and Tm³⁺ ions were fabricated by the conventional melt quenching method. The composition of the glasses are (76-x)% TeO₂ + 16 % ZnO + 5% BaO + x Tm₂O₃ + 3% Yb₂O₃, where x values are 0.075 mol %, 0.15 mol % and 0.3 mol % for Tm³⁺, respectively. Spectral properties of the powders were detailed to sort out for possible up-conversion (UC) emission mechanism in the range between 400−1700 nm under the wavelength of 975 nm excitation. The optical thermometry properties of the Yb³⁺/Tm³⁺: TZB glasses indicated that ³F₄ and ³H₄ levels of the Tm ³⁺ ions have thermally compatible energy pairs at energy ranging ΔE_M which is about 942.1 cm⁻¹ with the maximum absolute sensitivity of 0.0245 K⁻¹ at 553 K. With these properties, Yb³⁺/Tm³⁺: TZB glasses could be a promising candidate for remote temperature sensing in sensor technology.