Reproducible flaws unveil electrostatic aspects of semiconductor electrochemistry

Authors

Yan Boris Vogel, Curtin UniversityFollow
Long Zhang, University of WollongongFollow
Nadim A. Darwish, Curtin UniversityFollow
Vinicius R. Goncales, University of New South Wales
Anton P. Le Brun, Bragg Institute
J Justin Gooding, University of New South WalesFollow
Angela Molina, University of Murcia
Gordon G. Wallace, University of WollongongFollow
M Coote, Australian National UniversityFollow
Joaquin Gonzalez, University of Murcia
Simone Ciampi, Curtin UniversityFollow

RIS ID

118219

Publication Details

Vogel, Y. B., Zhang, L., Darwish, N., Goncales, V. R., Le Brun, A., Gooding, J. Justin., Molina, A., Wallace, G. G., Coote, M. L., Gonzalez, J. & Ciampi, S. (2017). Reproducible flaws unveil electrostatic aspects of semiconductor electrochemistry. Nature Communications, 8 (1), 2066-1-2066-9.

Abstract

Predicting or manipulating charge-transfer at semiconductor interfaces, from molecular electronics to energy conversion, relies on knowledge generated from a kinetic analysis of the electrode process, as provided by cyclic voltammetry. Scientists and engineers encountering non-ideal shapes and positions in voltammograms are inclined to reject these as flaws. Here we show that non-idealities of redox probes confined at silicon electrodes, namely full width at half maximum < 90.6 mV and anti-thermodynamic inverted peak positions, can be reproduced and are not flawed data. These are the manifestation of electrostatic interactions between dynamic molecular charges and the semiconductor's space-charge barrier. We highlight the interplay between dynamic charges and semiconductor by developing a model to decouple effects on barrier from changes to activities of surface-bound molecules. These findings have immediate general implications for a correct kinetic analysis of charge-transfer at semiconductors as well as aiding the study of electrostatics on chemical reactivity.