Recent advances in atomically precise metal nanoclusters for photothermal conversion

Metal nanoclusters (MNCs) are an emerging class of atomically precise nanomaterials with sizes comparable to the Fermi wavelength of free electrons, exhibiting discrete energy levels, molecular-like behaviors, and tunable physicochemical properties. Among these properties, photothermal conversion-the process of transforming absorbed light into thermal energy-has garnered considerable interest due to its vital importance in applications such as solar energy harvesting, photothermal therapy, and catalysis. This review begins by summarizing recent progress in synthetic strategies for MNCs, including kinetic control, seeded growth, in situ two-phase ligand exchange, and metal exchange, which help overcome challenges such as polydispersity, low yield, restricted surface functionality, and lengthy synthesis times. Subsequently, a comprehensive analysis is provided on the photothermal conversion behaviors of various MNC systems (e.g., coinage metal nanoclusters, Ti NCs, and Mo NCs) reported in the past five years, with in-depth discussion of their structural characteristics, absorption properties, photothermal conversion efficiencies, and underlying conversion mechanisms. Finally, the review addresses current challenges and prospects for advancing MNC-based photothermal technologies via atomic-level engineering and interdisciplinary approaches. Through this in-depth and systematic review, we endeavor to provide scholars dedicated to metal nanocluster research-as well as experts engaged in photothermal conversion and its diverse applications-with valuable scientific insights. We are confident that this contribution will not only catalyze innovative breakthroughs but also unlock exciting new frontiers within this vibrant and rapidly evolving field of study.