Single electron charging events on Au–Ag alloy nanoclusters

Highly monodisperse, hexanethiol (HT) protected Au–Ag alloy clusters of size 1 nm–2 nm, have been prepared and characterized by UV–Vis spectroscopy, FT-IR spectroscopy and transmission electron microscopy (TEM). The alloy clusters have been utilized to follow discrete single electron charging events both in the solution phase using electrochemical techniques and in the dry state, by employing scanning tunneling microscopy (STM). Fairly well-defined charging peaks are observed for an ensemble of alloy clusters in the solution phase. A single alloy cluster on highly oriented pyrolytic graphite (HOPG) in the dry state exhibits a typical Coulomb staircase I–V curve at room temperature.