Fluorescence Lifetime-Based Luminescent Thermometry Material with Lifetime Varying over a Factor of 50

Abstract

Recently, the growing demand for temperature detection is pushing forward the flourishing development of noncontact optical thermometry. Herein, a new red phosphor Sr₂InTa_1-xO₆:xMn⁴⁺ (SIT:xMn⁴⁺) was first constructed and systematically investigated. Based on the fairly rapid decline of the lifetime from 0.403 to 0.008 ms by increasing the temperature from 25 to 450 K, a noncontact optical thermometer can be made from phosphor SIT:0.003Mn⁴⁺ with S_r = 1.396% K^-1 at 375 K and S_a = 0.0012 K^-1 at 300 K. Because the luminescence is based on the outermost 3d orbits of Mn⁴⁺, the lifetime of SIT:xMn⁴⁺ is quite sensitive to the temperature, leading to a rapid decline of the lifetime with the increase in temperature. Moreover, multiple rounds of variable-temperature studies were performed to demonstrate the stability and reversibility of SIT:0.003Mn⁴⁺. This work suggests that Mn⁴⁺-phosphors are promising candidates for application as optical thermometric material.