Ambipolar transport in an electrochemically gated single-molecule field-effect transistor

Ismael Díez-Pérez, Zhihai Li, Shaoyin Guo, Christopher Madden, Helin Huang, Yanke Che, Xiaomei Yang, Ling Zang, Nongjian Tao

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Charge transport is studied in single-molecule junctions formed with a 1,7-pyrrolidine-substituted 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) molecular block using an electrochemical gate. Compared to an unsubstituted-PTCDI block, spectroscopic and electrochemical measurements indicate a reduction in the highest occupied (HOMO)-lowest unoccupied (LUMO) molecular orbital energy gap associated with the electron donor character of the substituents. The small HOMO-LUMO energy gap allows for switching between electron- and hole-dominated charge transports as a function of gate voltage, thus demonstrating a single-molecule ambipolar field-effect transistor. Both the unsubstituted and substituted molecules display similar n-type behaviors, indicating that they share the same n-type conduction mechanism. However, the substituted-PTCDI block shows a peak in the source-drain current vs gate voltage characteristics for the p-type transport, which is attributed to a two-step incoherent transport via the HOMO of the molecule.

Original languageEnglish (US)
Pages (from-to)7044-7052
Number of pages9
JournalACS nano
Issue number8
StatePublished - Aug 28 2012


  • STM
  • ambipolar FET
  • electrochemical gate
  • single-molecule junction

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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