Nanocluster Chemistry and the Role of in Situ Fluorescence as an Analytical Tool

Abstract

Atomically precise metal nanoclusters are of high interest as photocatalysts, contrast agents for biomedical imaging, unique sensitizers for therapies, and more. However, these fluorescent materials are often synthesized as mixtures, especially when stabilized by peptides and other water-soluble ligands. Fluorescence spectroscopy, when acquired as a matrix of excitation/emission spectra and analyzed with principal component analysis, such as parallel factor (PARAFAC) analysis, can be highly informative and precise in assessing purity and the number of components in a sample. In this perspective, advances in metal nanoclusters are discussed, as well as the use of fluorescence excitation−emission matrix spectroscopy (fEEM) as a fast, nondestructive technique for assessing sample composition. Hot topics in cluster research including new classes of clusters, theoryguided experiments, and the use of a combination of analytical techniques for ensuring purity and accurate structure−property studies are discussed.