Analytical tools for the characterization and quantification of metal nanoclusters

The increasing exploitation of metallic nanoclusters (NC) in many different applications (e.g., in optoelectronic developments, energy storage, diagnosis applications in biomedicine or therapeutic agents, among others) necessitates sensitive techniques to characterize and quantify such nanomaterials in terms of physicochemical properties, surface state, colloidal stability, interaction with the environment or to track the clearance and distribution of the material once introduced into a living system. This chapter intends to provide a comprehensive overview of the different techniques typically used to identify, characterize, and quantify metallic NC. The state-of-the-art of the field will be first summarized. Then, the different characterization techniques will be grouped according to the information they can provide. For each of these groups, a brief description of the techniques, specific features, and concepts, as well as several examples, will be discussed. Some selected applications will be highlighted to show the capabilities, strengths, and weaknesses of each selected technique.