Inverse rectification in donor-acceptor molecular heterojunctions

Shannon K. Yee, Jibin Sun, Pierre Darancet, T. Don Tilley, Arun Majumdar, Jeffrey B. Neaton*, Rachel A. Segalman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Scopus citations

Abstract

The transport properties of a junction consisting of small donor-acceptor molecules bound to Au electrodes are studied and understood in terms of its hybrid donor-acceptor-electrode interfaces. A newly synthesized donor-acceptor molecule consisting of a bithiophene donor and a naphthalenediimide acceptor separated by a conjugated phenylacetylene bridge and a nonconjugated end group shows rectification in the reverse polarization, behavior opposite to that observed in mesoscopic p-n junctions. Solution-based spectroscopic measurements demonstrate that the molecule retains many of its original constituent properties, suggesting a weak hybridization between the wave functions of the donor and acceptor moieties, even in the presence of a conjugated bridge. Differential conductance measurements for biases as high as 1.5 V are reported and indicate a large asymmetry in the orbital contributions to transport arising from disproportionate electronic coupling at anode-donor and acceptor-cathode interfaces. A semi-empirical single Lorentzian coherent transport model, developed from experimental data and density functional theory based calculations, is found to explain the inverse rectification.

Original languageEnglish (US)
Pages (from-to)9256-9263
Number of pages8
JournalACS nano
Volume5
Issue number11
DOIs
StatePublished - Nov 22 2011

Keywords

  • donor-acceptor molecule
  • inverse rectification
  • molecular diode
  • single-molecule conductance

ASJC Scopus subject areas

  • General Engineering
  • General Physics and Astronomy
  • General Materials Science

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