Influence of applied potential on the impedance of alkanethiol SAMs

Harmonie Sahalov, Brigid O'Brien, Kathleen J. Stebe, Kalina A Hristova, Peter C. Searson

Research output: Contribution to journalArticle

Abstract

Self-assembled monolayers are generally considered to behave as dielectric layers with a capacitance that is dependent on the monolayer thickness and the relative permittivity that is determined by the hydrocarbon tail. We show that the impedance response of alkanethiol-modified gold surfaces can be modeled as a parallel network consisting of the capacitance and resistance of the monolayer over a wide potential range. At potentials positive to -0.3 V (Ag/AgCl), the monolayer resistance is greater than 106 Ω cm2; however, at more negative potentials, the monolayer resistance decreases exponentially with potential with an inverse slope of about 250 mV. Over the same potential range, the monolayer capacitance is independent of potential. Although the same behavior is observed on ultrasmooth, template-stripped gold, the resistance at any potential is larger than for evaporated gold. The progressive increase in permeability of the monolayer is associated with an increase in electric field at potentials negative to the potential of zero charge.

Original languageEnglish (US)
Pages (from-to)9681-9685
Number of pages5
JournalLangmuir
Volume23
Issue number19
DOIs
StatePublished - Sep 11 2007

Fingerprint

Monolayers
impedance
Gold
Capacitance
capacitance
gold
Self assembled monolayers
Hydrocarbons
Permittivity
Electric fields
permeability
templates
hydrocarbons
permittivity
slopes
electric fields

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Sahalov, H., O'Brien, B., Stebe, K. J., Hristova, K. A., & Searson, P. C. (2007). Influence of applied potential on the impedance of alkanethiol SAMs. Langmuir, 23(19), 9681-9685. https://doi.org/10.1021/la701398u

Influence of applied potential on the impedance of alkanethiol SAMs. / Sahalov, Harmonie; O'Brien, Brigid; Stebe, Kathleen J.; Hristova, Kalina A; Searson, Peter C.

In: Langmuir, Vol. 23, No. 19, 11.09.2007, p. 9681-9685.

Research output: Contribution to journalArticle

Sahalov, H, O'Brien, B, Stebe, KJ, Hristova, KA & Searson, PC 2007, 'Influence of applied potential on the impedance of alkanethiol SAMs', Langmuir, vol. 23, no. 19, pp. 9681-9685. https://doi.org/10.1021/la701398u
Sahalov, Harmonie ; O'Brien, Brigid ; Stebe, Kathleen J. ; Hristova, Kalina A ; Searson, Peter C. / Influence of applied potential on the impedance of alkanethiol SAMs. In: Langmuir. 2007 ; Vol. 23, No. 19. pp. 9681-9685.
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