The Temperature Imaging Study Based on the Time‐Resolved Luminescence Measurement of Mn ⁴⁺ ‐Doped Lu ₃ Al ₅ O ₁₂ Phosphor

Abstract Nowadays, optical thermometry with a non‐contact operation mode and fast response is crucial in micro/nano electronics. However, the existing temperature measurement methods have the problem of low sensitivity. Herein, a temperature sensing method based on time‐resolved integrated intensity ratio (TRIIR) of Mn 4+ ‐doped Lu 3 Al 5 O 12 (LuAG) phosphor is proposed for the purpose of improving the temperature sensitivity of optical temperature measurement. Compared with the thermometry based on fluorescence lifetime of LuAG: Mn 4+ , the relative sensitivity () is significantly improved. Furthermore, the is further boosted by changing the experimental condition. Specifically, under the experimental condition of and , the value reaches 11.86% K −1 at 325 K, and the temperature resolution can reach 0.07 K at 310 K. At the same time, the shift of the optimal temperature measurement range toward the high‐temperature zone can be achieved by reducing . Finally, with the help of a fluorescence microscope and an ICCD camera, the temperature imaging capability of LuAG: Mn 4+ phosphor based on the TRIIR method with a high spatial resolution (2.7 µm) is verified on a nickel circuit. These results reveal that the LuAG: Mn 4+ phosphor based on the temperature sensing method of TRIIR is very promising for future temperature imaging applications.