Diamond Nanothermometry

Abstract Measuring temperature at or far from equilibrium at the nanoscale is important in many fields of science and engineering. A variety of luminescent nanothermometers have been developed in the past decade for the measurements. Fluorescent nanodiamonds (FNDs) stand out from the rest in terms of biological use, because the nanomaterials contain negatively charged nitrogen‐vacancy (NV⁻) centers as photostable fluorophores and possess a number of remarkable properties including chemical inertness, negligible toxicity, versatile surface modification ability and, most importantly, exceptional temperature‐measurement precision. However, to enable practical applications of FNDs for temperature sensing in biological systems, conjugation of the particles with polymers, biomolecules, and/or other nanomaterials are often required. Gold/diamond nanohybrids are one of these combinations that enhance the temperature measurement versatility of the NV⁻ centers. Here, we provide a review of the recent advances in the research and development of diamond nanothermometry, with special focus on the synthesis, characterization, and applications of gold/diamond nanohybrids. Current challenges and future perspectives of the FND‐based nanothermometry are also discussed.