Electric double layer effect on observable characteristics of the tunnel current through a bridged electrochemical contact

Publication: Research - peer-reviewJournal article – Annual report year: 2007

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Electric double layer effect on observable characteristics of the tunnel current through a bridged electrochemical contact. / Kuznetsov, A.M.; Medvedev, I.G.; Ulstrup, Jens.

In: Journal of Chemical Physics, Vol. 127, No. 10, 2007, p. 104708.

Publication: Research - peer-reviewJournal article – Annual report year: 2007

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Kuznetsov, A.M.; Medvedev, I.G.; Ulstrup, Jens / Electric double layer effect on observable characteristics of the tunnel current through a bridged electrochemical contact.

In: Journal of Chemical Physics, Vol. 127, No. 10, 2007, p. 104708.

Publication: Research - peer-reviewJournal article – Annual report year: 2007

Bibtex

@article{82e2f9d79c6748ce901c2293488ea349,
title = "Electric double layer effect on observable characteristics of the tunnel current through a bridged electrochemical contact",
publisher = "American Institute of Physics",
author = "A.M. Kuznetsov and I.G. Medvedev and Jens Ulstrup",
note = "Copyright (2007) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.",
year = "2007",
doi = "10.1063/1.2766954",
volume = "127",
number = "10",
pages = "104708",
journal = "Journal of Chemical Physics",
issn = "0021-9606",

}

RIS

TY - JOUR

T1 - Electric double layer effect on observable characteristics of the tunnel current through a bridged electrochemical contact

A1 - Kuznetsov,A.M.

A1 - Medvedev,I.G.

A1 - Ulstrup,Jens

AU - Kuznetsov,A.M.

AU - Medvedev,I.G.

AU - Ulstrup,Jens

PB - American Institute of Physics

PY - 2007

Y1 - 2007

N2 - Scanning tunneling microscopy and electrical conductivity of redox molecules in conducting media (aqueous or other media) acquire increasing importance both as novel single-molecule science and with a view on molecular scale functional elements. Such configurations require full and independent electrochemical potential control of both electrodes involved. We provide here a general formalism for the electric current through a redox group in an electrochemical tunnel contact. The formalism applies broadly in the limits of both weak and strong coupling of the redox group with the enclosing metal electrodes. Simple approximate expressions better suited for experimental data analysis are also derived. Particular attention is given to the effects of the Debye screening of the electric potential in the narrow tunneling gap based on the limit of the linearized Poisson-Boltzmann equation. The current/overpotential relation shows a maximum at a position which depends on the ionic strength. It is shown, in particular, that the dependence of the maximum position on the bias voltage may be nonmonotonous. Approximate expressions for the limiting value of the slope of the current/overpotential dependence and the width of the maximum on the bias voltage are also given and found to depend strongly on both the Debye screening and the position of the redox group in the tunnel gap, with diagnostic value in experimental data analysis.

AB - Scanning tunneling microscopy and electrical conductivity of redox molecules in conducting media (aqueous or other media) acquire increasing importance both as novel single-molecule science and with a view on molecular scale functional elements. Such configurations require full and independent electrochemical potential control of both electrodes involved. We provide here a general formalism for the electric current through a redox group in an electrochemical tunnel contact. The formalism applies broadly in the limits of both weak and strong coupling of the redox group with the enclosing metal electrodes. Simple approximate expressions better suited for experimental data analysis are also derived. Particular attention is given to the effects of the Debye screening of the electric potential in the narrow tunneling gap based on the limit of the linearized Poisson-Boltzmann equation. The current/overpotential relation shows a maximum at a position which depends on the ionic strength. It is shown, in particular, that the dependence of the maximum position on the bias voltage may be nonmonotonous. Approximate expressions for the limiting value of the slope of the current/overpotential dependence and the width of the maximum on the bias voltage are also given and found to depend strongly on both the Debye screening and the position of the redox group in the tunnel gap, with diagnostic value in experimental data analysis.

KW - FREE-ENERGY SURFACES

KW - STATE

KW - CONDUCTANCE

KW - REDOX MOLECULES

KW - METALLOPROTEINS

KW - V-I CHARACTERISTICS

KW - STM PROCESSES

KW - SINGLE-MOLECULE

KW - MICROSCOPY

KW - TRANSITION-METAL-COMPLEXES

UR - http://link.aip.org/link/JCPSA6/v127/i10/p104708/s1

U2 - 10.1063/1.2766954

DO - 10.1063/1.2766954

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 10

VL - 127

SP - 104708

ER -