Application of AIEgens in Temperature Detection

Temperature is a pivotal factor governing the metabolic processes of biological organisms, and monitoring temperature at the cellular level with high spatial and temporal resolution holds significant importance for understanding physiological and pathological conditions. Conventional macroscopic thermometers are not suited for cellular-scale measurements, necessitating the development of microscopic molecular thermometers. Fluorescent molecular thermometers have received widespread attention due to their noninvasive nature and versatility in reporting various parameters. In particular, molecular thermometers with aggregation-induced emission (AIE) properties have gained prominence owing to their superior stability, excellent signal-to-noise ratio, high contrast, and adaptability. The luminescence of AIE fluorophores often relies on a restriction of intramolecular motion (RIM) mechanism; therefore, the fundamental premise underlying the design of AIE thermometers is the modulation of molecular motion through temperature variations. In this Review, we summarize recently reported AIE thermometers, focusing on their molecular design, temperature response mechanisms, and applications in cell imaging. Furthermore, an exploration of the structure–activity relationships governing these thermometers is undertaken with the aim of offering valuable design strategies for diverse AIE temperature sensors.