Single-molecule conductance of pyridine-terminated dithienylethene switch molecules.


Journal Article

We have investigated the conductance of individual optically switchable dithienylethene molecules in both their conducting closed configuration and nonconducting open configuration, using the technique of repeatedly formed break-junctions. We employed pyridine groups to link the molecules to gold electrodes in order to achieve relatively well-defined molecular contacts and stable conductance. For the closed form of each molecule, we observed a peak in the conductance histogram constructed without any data selection, allowing us to determine the conductance of the fully stretched molecules. For two different dithienylethene derivatives, these closed-configuration conductances were (3.3 ± 0.5) × 10(-5)G(0) and (1.5 ± 0.5) × 10(-6)G(0), where G(0) is the conductance quantum. For the open configuration of the molecules, the existence of electrical conduction via the molecule was evident in traces of conductance versus junction displacement, but the conductance of the fully stretched molecules was less than the noise floor of our measurement. We can set a lower limit of 30 for the on/off ratio for the simplest dithienylethene derivative we have investigated. Density functional theory calculations predict an on/off ratio consistent with this result.

Full Text

Duke Authors

Cited Authors

  • Tam, ES; Parks, JJ; Shum, WW; Zhong, Y-W; Santiago-Berríos, MB; Zheng, X; Yang, W; Chan, GK-L; Abruña, HD; Ralph, DC

Published Date

  • June 2011

Published In

Volume / Issue

  • 5 / 6

Start / End Page

  • 5115 - 5123

PubMed ID

  • 21574612

Pubmed Central ID

  • 21574612

Electronic International Standard Serial Number (EISSN)

  • 1936-086X

International Standard Serial Number (ISSN)

  • 1936-0851

Digital Object Identifier (DOI)

  • 10.1021/nn201199b


  • eng