Redox-active monolayers in mesoporous silicon
Date
2012
Authors
Ciampi, S.
Guan, B.
Darwish, N.
Reece, P.J.
Gooding, J.J.
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Journal article
Citation
Journal of Physical Chemistry C, 2012; 116(30):16080-16088
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Abstract
Herein, redox reactions at chemically derivatized porous silicon (PSi) films are investigated. Passivation of the PSi matrix, by replacing metastable Si-H termini with nonpolar Si-C=C-R linkages, allows the electrochemical PSi device to operate in aqueous environments under oxidizing conditions (i.e., electron hole accumulation regime). Cu(I)-catalyzed alkyne-azide cycloaddition reactions are used to anchor ferrocene derivatives and probe electrochemical reactions at the exceedingly large surface area-to-volume ratio of mesoporous PSi. The forward-biased p-type PSi/electrolyte interface retains a quasi-metallic behavior throughout its entire contour, and it does so for prolonged times even when the electrode is poised at potentials at which a bare silicon electrode would rapidly oxidize. The interfacial capacitance of the PSi matrix is, however, unexpectedly low. An explanation is proposed where PSi morphology and the semiconductor space-charge layer capacitance play a significant role in determining the charging properties of the electrode. These results are important for the application of porous semiconductor electrodes in sensing, electrocatalytic, and energy-conversion devices.
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Data source: supporting information, https://doi.org/10.1021/jp303980x
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Copyright 2012 American Chemical Society