Gateway state-mediated, long-range tunnelling in molecular wires
| Autor: | Andrea Vezzoli, Iain Grace, Harry M. O'Brien, Colin J. Lambert, Nicolò Ferri, Simon J. Higgins, Laurent Bouffier, Sara Sangtarash, Hatef Sadeghi, Richard J. Nichols |
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| Přispěvatelé: | Laboratoire d'études dynamiques et structurales de la sélectivité (LEDSS), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Sch Biol & Chem Sci, Queen Mary University of London (QMUL) |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Condensed Matter - Mesoscale and Nanoscale Physics FOS: Physical sciences Conductance Viologen Fermi energy 02 engineering and technology Conjugated system 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry Molecular wire Chemical physics Mesoscale and Nanoscale Physics (cond-mat.mes-hall) medicine Moiety Molecule General Materials Science 0210 nano-technology ComputingMilieux_MISCELLANEOUS Quantum tunnelling medicine.drug |
| Zdroj: | Nanoscale Nanoscale, Royal Society of Chemistry, 2018, 10 (6), pp.3060-3067. ⟨10.1039/C7NR07243K⟩ Nanoscale (2017) |
| ISSN: | 2040-3372 2040-3364 |
| Popis: | If the factors controlling the decay in single-molecule electrical conductance G with molecular length L could be understood and controlled, then this would be a significant step forward in the design of high-conductance molecular wires. For a wide variety of molecules conducting by phase coherent tunneling, conductance G decays with length following the relationship G = Aexp-\b{\eta}L. It is widely accepted that the attenuation coefficient \b{\eta} is determined by the position of the Fermi energy of the electrodes relative to the energy of frontier orbitals of the molecular bridge, whereas the terminal anchor groups which bind to the molecule to the electrodes contribute to the pre-exponential factor A. We examine this premise for several series of molecules which contain a central conjugated moiety (phenyl, viologen or {\alpha}-terthiophene) connected on either side to alkane chains of varying length, with each end terminated by thiol or thiomethyl anchor groups. In contrast with this expectation, we demonstrate both experimentally and theoretically that additional electronic states located on thiol anchor groups can significantly decrease the value of \b{eta}, by giving rise to resonances close to EF through coupling to the bridge moiety. This interplay between the gateway states and their coupling to a central conjugated moiety in the molecular bridges creates a new design strategy for realising higher-transmission molecular wires by taking advantage of the electrode-molecule interface properties. |
| Databáze: | OpenAIRE |
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