Tellurite glasses codoped with Tb³⁺ and Ag for colorimetric optical thermometry

Abstract

Two series of Tb 3 + - and AgNP-doped lithium tellurite glasses were synthesized and investigated as optical thermometers over the 298–373 K range. The thermally driven competition between the Te 4+ broad red emission (~608 nm) and the Tb 3+ green emission (~545 nm) produces a visible color change from orange-yellow to yellow-green with increasing temperature, confirmed by CIE chromaticity diagrams and UV-illuminated photographs. AgNPs amplify the Tb 3+ → Te 4+ energy transfer through their localized surface plasmon resonance (LSPR) near-field, enhancing thermometric performance. The ratiometric parameter Δ = I (608 nm)/ I (494 nm) yields a relative sensitivity ( S r ) of 2.5% K −1 at 298 K for TL:Te 4+ /0.5Tb 3+ , and 2.18% K −1 for TL:Te 4+ /1.0Tb 3+ /1.2Ag under 355 nm excitation, surpassing several Tb 3+ -doped glass thermometers reported in the literature. These results establish the system as a high-performance, colorimetrically readable optical thermometer for non-contact temperature sensing for different applications.

The authors' abstract, as published at the source. Journal of Alloys and Compounds, 2026 · DOI ↗