Reductive electron transfer dynamics in gold nanocluster films contacted with aqueous electrolytes

Abstract

Reductive electron transfer dynamics in the multilayer film of alkanethiolate monolayer protected clusters (so-called MPCs) contacted with an aqueous electrolyte was studied. As determined by potential step chronoamperometry, electrons are transported within the film phenomenologically via the diffusion-like hopping (self-exchange) between the localized MPC sites with an average first order rate constant of 104s−1. This value is comparable with those for the similar kind of films immersed in organic electrolytes but much smaller than those for the all-solid or dry films. It thus reveals that the solvent swelling presents negligible effect on the electron hopping dynamics and that the electron transfer is most likely limited by the diffusive redistribution of the counterions in order to keep the local electroneutrality.