Graphene as a Promising Electrode for Low-Current Attenuation in Nonsymmetric Molecular Junctions



Zhang, Qian, Liu, Longlong, Tao, Shuhui, Wang, Congyi, Zhao, Cezhou, Gonzalez, Cesar, Dappe, Yannick J, Nichols, Richard J ORCID: 0000-0002-1446-8275 and Yang, Li ORCID: 0000-0002-1040-4223
(2016) Graphene as a Promising Electrode for Low-Current Attenuation in Nonsymmetric Molecular Junctions. NANO LETTERS, 16 (10). pp. 6534-6540.

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Abstract

We have measured the single-molecule conductance of 1,n-alkanedithiol molecular bridges (n = 4, 6, 8, 10, 12) on a graphene substrate using scanning tunneling microscopy (STM)-formed electrical junctions. The conductance values of this homologous series ranged from 2.3 nS (n = 12) to 53 nS (n = 4), with a decay constant β<sub>n</sub> of 0.40 per methylene (-CH<sub>2</sub>) group. This result is explained by a combination of density functional theory (DFT) and Keldysh-Green function calculations. The obtained decay, which is much lower than the one obtained for symmetric gold junctions, is related to the weak coupling at the molecule-graphene interface and the electronic structure of graphene. As a consequence, we show that using graphene nonsymmetric junctions and appropriate anchoring groups may lead to a much-lower decay constant and more-conductive molecular junctions at longer lengths.

Item Type: Article
Uncontrolled Keywords: Graphene-based-electrode, single molecule conductance, charge transport, alkanedithiol, density functional theory
Depositing User: Symplectic Admin
Date Deposited: 31 Oct 2016 10:15
Last Modified: 19 Jan 2023 07:27
DOI: 10.1021/acs.nanolett.6b03180
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3004209