In situ measurements of oligoaniline conductance: Linking electrochemistry and molecular electronics

Fan Chen, Colin Nuckolls, Stuart Lindsay

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

The single-molecule conductance of a dithiolated aniline trimer has been measured under potential control and also under an inert solvent. In each experiment, two sets of currents are found, differing by a factor 4, and these are tentatively assigned to differing connections to the electrodes (e.g., on-top vs. hollow sites). The conductances peak (to 17 ± 1.6 and 5.8 ± 0.85 nS) between the first and second oxidations of the molecule and change smoothly with surface potential. There is no evidence for a coexistence of oxidized and reduced molecules. Measurements made at a fixed surface potential as a function of tip to substrate bias show a peak current at 0.1 V followed by a region of negative differential resistance. This is accounted for semi-quantitatively by modification of the local potential by the applied bias altering the oxidation state of the molecule under the probe. Measurements made in toluene are Ohmic, indicating that the tip does not alter the oxidation state of the molecule in the absence of screening ions. We discuss the role of gap geometry and bonding in these processes.

Original languageEnglish (US)
Pages (from-to)236-243
Number of pages8
JournalChemical Physics
Volume324
Issue number1 SPEC. ISS.
DOIs
StatePublished - May 9 2006

Keywords

  • Electrochemical gating
  • Molecular electronics
  • Oligo aniline
  • Single molecule conductance

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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