title: Single-electron transistor of a single organic molecule with access to several redox states.
abstract: A combination of classical Coulomb charging, electronic level spacings, spin, and vibrational modes determines the single-electron transfer reactions through nanoscale systems connected to external electrodes by tunnelling barriers. Coulomb charging effects have been shown to dominate such transport in semiconductor quantum dots, metallic and semiconducting nanoparticles, carbon nanotubes, and single molecules. Recently, transport has been shown to be also influenced by spin--through the Kondo effect--for both nanotubes and single molecules, as well as by vibrational fine structure. Here we describe a single-electron transistor where the electronic levels of a single pi-conjugated molecule in several distinct charged states control the transport properties. The molecular electronic levels extracted from the single-electron-transistor measurements are strongly perturbed compared to those of the molecule in solution, leading to a very significant reduction of the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital. We suggest, and verify by simple model calculations, that this surprising effect could be caused by image charges generated in the source and drain electrodes resulting in a strong localization of the charges on the molecule.
authors.affiliation: Department of Microtechnology and Nanoscience/MC2, University of Technology, Chalmers, Göteborg, Sweden.
authors.forename: Sergey
authors.initials: S
authors.lastname: Kubatkin
authors.forename: Andrey
authors.initials: A
authors.lastname: Danilov
authors.forename: Mattias
authors.initials: M
authors.lastname: Hjort
authors.forename: Jérôme
authors.initials: J
authors.lastname: Cornil
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Brédas
authors.forename: Nicolai
authors.initials: N
authors.lastname: Stuhr-Hansen
authors.forename: Per
authors.initials: P
authors.lastname: Hedegård
authors.forename: Thomas
authors.initials: T
authors.lastname: Bjørnholm