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Published June 28, 2011 | public
Journal Article Open

Single-Molecule Conductance of Pyridine-Terminated Dithienylethene Switch Molecules


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.

Additional Information

© 2011 American Chemical Society. Received for review March 30, 2011 and accepted May 16, 2011. We thank L. Venkataraman, M. Kamenetska, J. Widawsky, D. Stewart, J. Tan, and S. Conte for technical help and discussions. We acknowledge funding from the NSF via the Cornell Center for Materials Research (NSF/DMR-0520404) and the Cornell Center for Chemical Interfacing, a Phase I Center for Chemical Innovation (NSF/CHE-0847926). E.S.T. was partially supported by the National Science and Engineering Research Council of Canada. M.B.S. acknowledges financial support from the Provost's Academic Diversity Postdoctoral Fellowship from Cornell University.

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Supplemental Material - nn201199b_si_001.pdf


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August 22, 2023
August 22, 2023