Impedance spectroscopy of self-assembled monolayers on Au(111): Evidence for complex double-layer structure in aqueous NaClO4 at the potential of zero charge

Richard P. Janek, W. Ronald Fawcett, Abraham Ulman

Research output: Contribution to journalArticle

Abstract

The impedance of a Au(111) electrode modified by three different self-assembled monolayers has been studied over a wide frequency range in aqueous NaClO4 solutions. The impedance characteristics of the bare electrode are compared with those of the same electrode modified with decanethiol, ω-hydroxydecanethiol, and 4'′-hydroxy-4-mercaptobiphenyl. In the case of the decanethiol system the interfacial impedance can be represented as a capacitor due to the self-assembled monolayer in series with the solution resistance. However, for the latter two systems, the impedance behavior is more complex with a high resistance in the monolayer parallel to the expected capacitance. This behavior is quite different than that discussed to date in the literature and assumed in the interpretation of voltammetric data for modified electrodes. The parameters for these systems are reported here as a function of electrolyte concentration at the point of zero charge on the bare Au(111). The consequences of the present observations are discussed with respect to the phenomena observed for these systems.

Original languageEnglish (US)
Pages (from-to)8550-8558
Number of pages9
JournalJournal of Physical Chemistry B
Volume101
Issue number42
StatePublished - Oct 16 1997

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Self assembled monolayers
Spectroscopy
impedance
Electrodes
electrodes
spectroscopy
high resistance
Electrolytes
Monolayers
capacitors
Capacitors
Capacitance
frequency ranges
capacitance
electrolytes
aqueous solutions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Engineering(all)

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Impedance spectroscopy of self-assembled monolayers on Au(111) : Evidence for complex double-layer structure in aqueous NaClO4 at the potential of zero charge. / Janek, Richard P.; Fawcett, W. Ronald; Ulman, Abraham.

In: Journal of Physical Chemistry B, Vol. 101, No. 42, 16.10.1997, p. 8550-8558.

Research output: Contribution to journalArticle

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