Insights into the Synthesis Mechanism of Ag Nanoclusters.

The current understanding of the synthesis mechanisms of noble metal clusters is limited, in particular for Ag clusters. Here, we present a detailed investigation into the synthesis process of atomically monodisperse Ag clusters, prepared via reduction of AgNO in the presence of dithiolate ligands. Using optical spectroscopy, mass spectrometry, and X-ray spectroscopy, it was determined that the synthesis involves a rapid nucleation and growth to species with up to a few hundred Ag atoms. From these larger species, Ag clusters are formed and their concentration increases steadily over time. Oxygen plays an important role in the etching of large particles to Ag. No other stable Ag cluster species are observed at any point during the synthesis.