Authors
Yu Hao, Xiangping Li, Yan Li, Jiani Luo, Hongquan Yu, Baojiu Chen
Published in
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. Volume 363. Issue Pt 2. Pages 128463. Jul 15, 2026. Epub Jul 15, 2026.
Abstract
Real-time temperature monitoring of edible oil is crucial for cooking safety and quality. Conventional contact and infrared methods suffer from slow response, high cost, or low accuracy. Herein, a series of La3+-modulated Yb0.2Zr0.8O1.9: Ho3+ upconversion (UC) phosphors was synthesized via a high-temperature solid-state reaction. La3+ doping up to 30% preserves the cubic fluorite phase and significantly enhances UC luminescence by lowering the local crystal field symmetry around Ho3+ ions, achieving an 8.29-fold green emission enhancement with a color purity exceeding 85% under 980 nm excitation. Temperature-dependent luminescence measurements over 303-723 K reveal that the visible emissions undergo conventional thermal quenching, whereas the near-infrared (NIR) emission exhibits negative thermal quenching attributed to the enhanced non-radiative relaxation and phonon-assisted energy transfer. Based on the fluorescence intensity ratio (FIR) of non-thermally coupled levels of Ho3+, the thermometric performance was found to be strongly dependent on La3+ concentration, with the optimal relative sensitivity of 1.92% K-1 achieved at 7% La3+. A flexible film sensor was further fabricated from this material, which enables precise, non-invasive real-time temperature detection of edible oil with a relative error below 1%. This work provides a La3+-modulation strategy for high-performance UC thermometry and a practical platform for non-contact food temperature monitoring.
PMID:
42485695
Bibliographic data and abstract were imported from PubMed on 23 Jul 2026.
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