Electronic transport in single molecule junctions: control of the molecule-electrode coupling through intramolecular tunneling barriers.

Danilov, Andrey; Kubatkin, Sergey; Kafanov, Sergey; Hedegård, Per; Stuhr-Hansen, Nicolai; Moth-Poulsen, Kasper; Bjørnholm, Thomas · Nano Lett · 2008

basic_science · Level V

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Abstract

We report on single molecule electron transport measurements of two oligophenylenevinylene (OPV3) derivatives placed in a nanogap between gold (Au) or lead (Pb) electrodes in a field effect transistor device. Both derivatives contain thiol end groups that allow chemical binding to the electrodes. One derivative has additional methylene groups separating the thiols from the delocalized pi-electron system. The insertion of methylene groups changes the open state conductance by 3-4 orders of magnitude and changes the transport mechanism from a coherent regime with finite zero-bias conductance to sequential tunneling and Coulomb blockade behavior.