Visual ratiometric optical thermometer with high sensitivity and excellent signal discriminability based on LiScSiO4:Ce3+, Tb3+ thermochromic phosphor

Developing optical thermometer phosphors with high sensitivity, high signal discriminability and strong fluorescence intensity is ongoing. A dual-emitting thermochromic phosphor, LiScSiO4:Ce3+, Tb3+, was successfully synthesized via solid-state reaction method. The crystal structure, electronic structure, luminescent performance and thermal luminescence behaviors as well as the luminescence mechanism of LiScSiO4:Ce3+, Tb3+ were systematically investigated. Due to the energy transfer and different thermoluminescence behaviors between Ce3+ and Tb3+, high relative sensitivity (2.2 % K-1@473 K), excellent signal discriminability (5747 cm-1), outstanding temperature resolution (0.067 K) and good repeatability, as well as efficient emission at high temperatures were achieved based on the fluorescence intensity ratio of Ce3+ and Tb3+, indicating its potential in ratiometric optical thermometer. Moreover, the excellent visualizing thermochromic enable LiScSiO4:Ce3+, Tb3+ to be used as safety sign in variable temperature environment to monitor temperature distribution.