Impedance spectroscopy of self-assembled monolayers on Au(111): Sodium ferrocyanide charge transfer at modified electrodes

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

Research output: Contribution to journalArticle

Abstract

The Faradaic 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 in the presence of 1 mM [Fe(CN)6]4-/3-. 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. The 4′-hydroxy-4-mercaptobiphenyl molecule is susceptible to π-π interactions and is of special interest as a mediator of electron transfer. In the case of the decanethiol and ω-hydroxydecanethiol systems the interfacial impedance can be modeled by the Randles circuit. However, for the 4′-hydroxy-4-mercaptobiphenyl system, the impedance behavior is more complex with a resistance in the monolayer parallel to and distinguishable from the expected Faradaic impedance. This behavior is quite different from 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 the type of electrode modification. The consequences of the present observations are discussed with respect to the phenomena observed.

Original languageEnglish (US)
Pages (from-to)3011-3018
Number of pages8
JournalLangmuir
Volume14
Issue number11
StatePublished - May 26 1998

Fingerprint

Self assembled monolayers
Charge transfer
Sodium
charge transfer
sodium
Spectroscopy
impedance
Electrodes
electrodes
spectroscopy
Monolayers
electron transfer
frequency ranges
hexacyanoferrate II
aqueous solutions
Molecules
Electrons
Networks (circuits)
molecules
interactions

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry

Cite this

Impedance spectroscopy of self-assembled monolayers on Au(111) : Sodium ferrocyanide charge transfer at modified electrodes. / Janek, Richard P.; Fawcett, W. Ronald; Ulman, Abraham.

In: Langmuir, Vol. 14, No. 11, 26.05.1998, p. 3011-3018.

Research output: Contribution to journalArticle

@article{52e04bdc140048e3b7e5a39631c9ceae,
title = "Impedance spectroscopy of self-assembled monolayers on Au(111): Sodium ferrocyanide charge transfer at modified electrodes",
abstract = "The Faradaic 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 in the presence of 1 mM [Fe(CN)6]4-/3-. 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. The 4′-hydroxy-4-mercaptobiphenyl molecule is susceptible to π-π interactions and is of special interest as a mediator of electron transfer. In the case of the decanethiol and ω-hydroxydecanethiol systems the interfacial impedance can be modeled by the Randles circuit. However, for the 4′-hydroxy-4-mercaptobiphenyl system, the impedance behavior is more complex with a resistance in the monolayer parallel to and distinguishable from the expected Faradaic impedance. This behavior is quite different from 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 the type of electrode modification. The consequences of the present observations are discussed with respect to the phenomena observed.",
author = "Janek, {Richard P.} and Fawcett, {W. Ronald} and Abraham Ulman",
year = "1998",
month = "5",
day = "26",
language = "English (US)",
volume = "14",
pages = "3011--3018",
journal = "Langmuir",
issn = "0743-7463",
publisher = "American Chemical Society",
number = "11",

}

TY - JOUR

T1 - Impedance spectroscopy of self-assembled monolayers on Au(111)

T2 - Sodium ferrocyanide charge transfer at modified electrodes

AU - Janek, Richard P.

AU - Fawcett, W. Ronald

AU - Ulman, Abraham

PY - 1998/5/26

Y1 - 1998/5/26

N2 - The Faradaic 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 in the presence of 1 mM [Fe(CN)6]4-/3-. 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. The 4′-hydroxy-4-mercaptobiphenyl molecule is susceptible to π-π interactions and is of special interest as a mediator of electron transfer. In the case of the decanethiol and ω-hydroxydecanethiol systems the interfacial impedance can be modeled by the Randles circuit. However, for the 4′-hydroxy-4-mercaptobiphenyl system, the impedance behavior is more complex with a resistance in the monolayer parallel to and distinguishable from the expected Faradaic impedance. This behavior is quite different from 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 the type of electrode modification. The consequences of the present observations are discussed with respect to the phenomena observed.

AB - The Faradaic 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 in the presence of 1 mM [Fe(CN)6]4-/3-. 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. The 4′-hydroxy-4-mercaptobiphenyl molecule is susceptible to π-π interactions and is of special interest as a mediator of electron transfer. In the case of the decanethiol and ω-hydroxydecanethiol systems the interfacial impedance can be modeled by the Randles circuit. However, for the 4′-hydroxy-4-mercaptobiphenyl system, the impedance behavior is more complex with a resistance in the monolayer parallel to and distinguishable from the expected Faradaic impedance. This behavior is quite different from 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 the type of electrode modification. The consequences of the present observations are discussed with respect to the phenomena observed.

UR - http://www.scopus.com/inward/record.url?scp=0032069401&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032069401&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0032069401

VL - 14

SP - 3011

EP - 3018

JO - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 11

ER -