Optical Nanoscale Thermometry: From Fundamental Mechanisms to Emerging Practical Applications

Knowledge of temperature and temperature gradients with nanoscale resolution is critical for a variety of applications in medicine, nanoelectronics, biology, and solid‐state‐based devices. The number of existing nanothermometry techniques is remarkably large, varying for materials, mechanisms, sensitivity, and operating ranges. In this work, a selected group of prominent nanoscale thermosensors is reviewed, which are all‐optical and nanoparticle‐based. Specifically, the focus is on the analysis of their fundamental mechanism to identify absolute, intrinsic capabilities and limitations of each nanothermometry platform. Prominent applications as well as future challenges and opportunities in the field are discussed. In this work, a selection of nanothermometry techniques for measuring temperature at the nanoscale is reviewed. The focus is on thermosensors, which are all‐optical and nanoparticle‐based. An in‐depth analysis of their fundamental mechanisms is provided, as these set the absolute, intrinsic capabilities and limitations of each nanothermometry platform. Prominent applications as well as future challenges and opportunities are discussed.