Blue-light-excitable Y2W3O12:Eu phosphor enabling efficient high-temperature photothermal feedback

A blue-light-excitable Y 2 W 3 O 12 :Eu FIR thermometer is developed using 466 nm excitation matched to commercial InGaN LEDs. • The negative thermal expansion effect endows the phosphor with excellent resistance to thermal quenching, retaining ∼40% of its emission at 603 K. • The thermometer achieves a maximum relative sensitivity of 0.15% K −1 , repeatability >99.3%, and low temperature uncertainty below 4.2 K from 363 to 603 K. The development of reliable and cost-effective fluorescence intensity ratio (FIR) thermometers for high-temperature environments is urgently required, yet most existing probes rely on near-infrared stimulated upconversion or ultraviolet excited downshifting, which suffer from high system complexity, optical damage, and high cost. In response to this dilemma, herein I report a blue-light-excitable FIR thermometer based on Eu 3+ -doped Y 2 W 3 O 12 (YWO) negative thermal expansion (NTE) phosphor. Under 466 nm blue excitation, the YWO:Eu phosphor exhibits efficient downshifting luminescence dominated by the 5 D 0 → 7 F 2 electric dipole transition at 612 nm, and the NTE effect endows the phosphor with excellent resistance to thermal quenching. The proposed thermometer achieves a maximum relative sensitivity of 0.15% K −1 , together with excellent repeatability (>99.3%) and low temperature uncertainty (<4.2 K) over the 363-603 K range. Also, the single-wavelength excitation strategy allows the use of a commercial blue light emitting diode (LED), eliminating the need for costly tunable lasers or dual-wavelength setups and thereby reducing system complexity and cost. These results demonstrate that the blue-light-excited YWO:Eu FIR thermometer is a promising candidate for non-contact photothermal feedback in high-temperature environments.