Exploiting novel optical thermometry near room temperature with a combination of phase-change host and luminescent Pr3+ ion

Abstract Luminescence thermometry manifests tremendous application potential in the optoelectronic field, and highly sensitive response to an alteration in temperature is their important development direction. Herein, we propose a Pr3+-doped LiYO2 phosphor that shows outstanding temperature sensing performance approaching room temperature (320–330 K). The thermal and structural investigations reveal that the phase transition of LiYO2 between the low-temperature (β) and high-temperature (α) phases is reversible. Along with the phase transformation from the β-type to the α-type, the local site symmetry of the Pr3+-doped sites is modified, leading to a dramatic reduction of the 3P0 emission in comparison to the 1D2 one. Such an obvious photoluminescence change through the phase transformation process presents outstanding optical thermometric performance, yielding a relative sensitivity Sr of 23.04%·K−1 at 329 K and a repeatability capability not lower than 98.9%. Moreover, By virtue of the excellent color variation of fluorescence in a temperature interval of ~30 K, the as-prepared samples also demonstrate promising thermochromic and anti-counterfeiting applications. Hence, our findings might offer some useful inspiration for exploring high-performance luminescent thermometers and understanding the structure-property relationship in material science.