Visual ratiometric optical thermometer with high sensitivity and excellent signal discriminability based on...

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.