Reproducible flaws unveil electrostatic aspects of semiconductor electrochemistry

作者：Vogel Yan B.; Zhang Long; Darwish Nadim; Goncales Vinicius R.; Le Brun Anton; Gooding J. Justin; Molina Angela; Wallace Gordon G.; Coote Michelle L.; Gonzalez Joaquin^*; Ciampi Simone^*

来源：Nature Communications, 2017, 8(1): 2066.

DOI：10.1038/s41467-017-02091-1

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.

• 出版日期2017-12-12