The impact of surface coverage on the kinetics of electron transfer through redox monolayers on a silicon electrode surface

Authors

Simone Ciampi, University of New South WalesFollow
Moinul H. Choudhury, University of New South Wales
Shahrul Ahmad, University of New South Wales
Nadim A. Darwish, University of New South WalesFollow
Anton LeBrun, Australian Nuclear Science and Technology Organisation (ANSTO)Follow
J Justin Gooding, University of New South Wales

RIS ID

104004

Publication Details

Ciampi, S., Choudhury, M. H., Ahmad, S., Darwish, N. A., LeBrun, A. & Gooding, J. Justin. (2015). The impact of surface coverage on the kinetics of electron transfer through redox monolayers on a silicon electrode surface. Electrochimica Acta, 186 216-222.

Abstract

The impact of the coverage of ferrocene moieties, attached to a silicon electrode modified via hydrosilylation of a dialkyne, on the kinetics of electron transfer between the redox species and the electrode is explored. The coverage of ferrocene is controlled by varying the coupling time between azidomethylferrocene and the distal alkyne of the monolayer via the copper assisted azide-alkyne cycloaddition reaction. All other variables in the surface preparation are maintained identical. What is observed is that the higher the surface coverage of the ferrocene moieties the faster the apparent rates of electron transfer. This surface coverage-dependent kinetic effect is attributed to electrons hopping between ferrocene moieties across the redox film toward hotspots for the electron transfer event. The origin of these hotspots is tentatively suggested to result from minor amounts of oxide on the underlying silicon surface that reduce the barrier for the electron transfer.