Review—Structural and Optical Interpretations on Phosphor-Based Optical Thermometry

Abstract

This comprehensive review article discusses the brief history, development, and applications of phosphor-based optical thermometers, which have become increasingly important in various fields due to their ability to measure temperature remotely and with high precision. The article highlights the importance of choosing the suitable phosphor material for a given application, considering factors such as crystal structure and mode of thermometry. It then delves into the structural importance of phosphors, discussing their luminescent properties. The review focuses particularly on fluorescence-based temperature-dependent techniques, including the fluorescence intensity ratio method, which has garnered significant attention due to its straightforward implementation, affordability, and self-referential nature. The article discusses the mathematical formulations underlying this method, including the Boltzmann distribution and the effective lifetime calculation. The review also explores the concept of dual-mode thermometry, which involves the use of multiple luminescent centers to enhance sensitivity and thermal stability. This approach is particularly useful in applications where single-emitter thermometers are vulnerable to variations in excitation intensity or detector stability. The article highlights the advantages, limitations, and future developments of phosphor-based thermometers, including their ability to measure temperature remotely and with high precision. Highlights Suitability of double perovskite phosphors for optical thermometry applications. Double perovskite structure influence on the sensitivities of temperature sensors. Fluorescence intensity ratio method is effective for the interpretation of thermal sensor sensitivities. Phosphors can be used as optical temperature sensors at higher temperatures.