Nanoclusters formed by gas-phase condensation and their size-dependent properties

The study of nanoclusters (NCs) has provided invaluable insights into the interactions among small assemblies of atoms, where their size encapsulates vital information about atom-atom synergies that govern morphology, defects, and electronic states. The precise tuning of NC size has become a pivotal factor in optimizing their performance. Evolving in tandem with other ultra-high vacuum (UHV) techniques over recent decades, the gas-phase condensation technique has emerged as a remarkable approach to synthesize solvent-free and ligand-free NCs with tailored size distributions. This review provides a dual focus on the formation and size control of NCs through the gas-phase condensation technique, elucidating its advantages and limitations primarily through the use of magnetron-based sputtering sources, as well as on the size-dependent physical, chemical and electronic properties of NCs in their diverse applications. The capacity to engineer NCs with precision down to the number of atoms has ushered in a new era of transformative impacts on chemistry, materials science, and beyond. The precise control of NC size and composition has opened new opportunities for tailoring their size-specific properties for specific applications, thereby harnessing their full potential to meet the grand challenges of the rapidly evolving world of nanotechnology.