Charge transport in conjugated aromatic molecular junctions: Molecular conjugation and molecule-electrode coupling

Revital Cohen, Kurt Stokbro, Jan M L Martin, Mark A Ratner

Research output: Contribution to journalArticle

82 Citations (Scopus)

Abstract

The conductance of a single molecule transport junction is investigated in the Landauer-Imry regime of coherent tunneling transport. Utilizing aromatic systems with thiol end groups, we have calculated using density functional theory the expected conductance of junctions containing molecules with different levels of conjugation and of different lengths. The calculated variations in transport junction conductance are explained in terms of the continuity of the conjugation path between leads. Molecular conjugation describes this continuity within the molecule, and the interfacial terms (spectral densities or imaginary parts of the self-energy) describe its continuity at the molecule/metal interface. We compare the results from junction conductance calculations with isolated molecule electronic structure calculations These density functional theory calculations suggest that for these dithiol molecules, transport occurs mostly through the occupied orbital manifold. The decay of the transport with length is found to be exponential for poly-Ph dithiol molecules. We compare the calculated conductance of conjugated aromatic molecules with their molecular orbital calculations and with the Green's function formulation and evaluate the relative significance of different factors (such as energetic alignment and spectral density) that control the conductance of molecules.

Original languageEnglish
Pages (from-to)14893-14902
Number of pages10
JournalJournal of Physical Chemistry C
Volume111
Issue number40
DOIs
Publication statusPublished - Oct 11 2007

Fingerprint

conjugation
Charge transfer
Electrodes
Molecules
electrodes
molecules
thiols
continuity
Spectral density
Density functional theory
density functional theory
Orbital calculations
Molecular orbitals
Sulfhydryl Compounds
Green's function
Electronic structure
molecular orbitals
Green's functions
Metals
alignment

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Charge transport in conjugated aromatic molecular junctions : Molecular conjugation and molecule-electrode coupling. / Cohen, Revital; Stokbro, Kurt; Martin, Jan M L; Ratner, Mark A.

In: Journal of Physical Chemistry C, Vol. 111, No. 40, 11.10.2007, p. 14893-14902.

Research output: Contribution to journalArticle

@article{88cb9f471fb14be2af1d17074e5813ce,
title = "Charge transport in conjugated aromatic molecular junctions: Molecular conjugation and molecule-electrode coupling",
abstract = "The conductance of a single molecule transport junction is investigated in the Landauer-Imry regime of coherent tunneling transport. Utilizing aromatic systems with thiol end groups, we have calculated using density functional theory the expected conductance of junctions containing molecules with different levels of conjugation and of different lengths. The calculated variations in transport junction conductance are explained in terms of the continuity of the conjugation path between leads. Molecular conjugation describes this continuity within the molecule, and the interfacial terms (spectral densities or imaginary parts of the self-energy) describe its continuity at the molecule/metal interface. We compare the results from junction conductance calculations with isolated molecule electronic structure calculations These density functional theory calculations suggest that for these dithiol molecules, transport occurs mostly through the occupied orbital manifold. The decay of the transport with length is found to be exponential for poly-Ph dithiol molecules. We compare the calculated conductance of conjugated aromatic molecules with their molecular orbital calculations and with the Green's function formulation and evaluate the relative significance of different factors (such as energetic alignment and spectral density) that control the conductance of molecules.",
author = "Revital Cohen and Kurt Stokbro and Martin, {Jan M L} and Ratner, {Mark A}",
year = "2007",
month = "10",
day = "11",
doi = "10.1021/jp0795309",
language = "English",
volume = "111",
pages = "14893--14902",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "40",

}

TY - JOUR

T1 - Charge transport in conjugated aromatic molecular junctions

T2 - Molecular conjugation and molecule-electrode coupling

AU - Cohen, Revital

AU - Stokbro, Kurt

AU - Martin, Jan M L

AU - Ratner, Mark A

PY - 2007/10/11

Y1 - 2007/10/11

N2 - The conductance of a single molecule transport junction is investigated in the Landauer-Imry regime of coherent tunneling transport. Utilizing aromatic systems with thiol end groups, we have calculated using density functional theory the expected conductance of junctions containing molecules with different levels of conjugation and of different lengths. The calculated variations in transport junction conductance are explained in terms of the continuity of the conjugation path between leads. Molecular conjugation describes this continuity within the molecule, and the interfacial terms (spectral densities or imaginary parts of the self-energy) describe its continuity at the molecule/metal interface. We compare the results from junction conductance calculations with isolated molecule electronic structure calculations These density functional theory calculations suggest that for these dithiol molecules, transport occurs mostly through the occupied orbital manifold. The decay of the transport with length is found to be exponential for poly-Ph dithiol molecules. We compare the calculated conductance of conjugated aromatic molecules with their molecular orbital calculations and with the Green's function formulation and evaluate the relative significance of different factors (such as energetic alignment and spectral density) that control the conductance of molecules.

AB - The conductance of a single molecule transport junction is investigated in the Landauer-Imry regime of coherent tunneling transport. Utilizing aromatic systems with thiol end groups, we have calculated using density functional theory the expected conductance of junctions containing molecules with different levels of conjugation and of different lengths. The calculated variations in transport junction conductance are explained in terms of the continuity of the conjugation path between leads. Molecular conjugation describes this continuity within the molecule, and the interfacial terms (spectral densities or imaginary parts of the self-energy) describe its continuity at the molecule/metal interface. We compare the results from junction conductance calculations with isolated molecule electronic structure calculations These density functional theory calculations suggest that for these dithiol molecules, transport occurs mostly through the occupied orbital manifold. The decay of the transport with length is found to be exponential for poly-Ph dithiol molecules. We compare the calculated conductance of conjugated aromatic molecules with their molecular orbital calculations and with the Green's function formulation and evaluate the relative significance of different factors (such as energetic alignment and spectral density) that control the conductance of molecules.

UR - http://www.scopus.com/inward/record.url?scp=35548968881&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=35548968881&partnerID=8YFLogxK

U2 - 10.1021/jp0795309

DO - 10.1021/jp0795309

M3 - Article

AN - SCOPUS:35548968881

VL - 111

SP - 14893

EP - 14902

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 40

ER -