Dynamics of ionic liquid mediated quantised charging of monolayer-protected clusters

We present the first kinetic study of quantised double layer charging of monolayer-protected gold clusters in an ionic liquid. Cyclic voltammetry and electrochemical impedance measurements reveal that kinetic control is involved in the quantised cluster charging in these room temperature melts. The level of kinetic control varies up to one order of magnitude depending on ionic liquid composition, which may have implications for the development of future nanoelectronic devices. By studying the quantised charging process in the chemically relevant permutations of two anions and two cations, we find strong indications that the ionic liquid behaviour is not a linear combination of its composing ions' properties, but is dominated by specific interactions. Based on a Walden plot analysis, we hypothesise that the chemical availability of ions is different in the various liquids, and explains the differences in monolayer-protected gold cluster (MPC) charging rates.