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.


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.



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