Field-Effect Control of Graphene–Fullerene Thermoelectric Nanodevices

Gehring, Pascal and Harzheim, Achim and Spiece, Jean and Sheng, Yuewen and Rogers, Gregory and Evangeli, Charalambos and Mishra, Aadarsh and Robinson, Benjamin James and Porfyrakis, Kyriakos and Warner, Jamie H. and Kolosov, Oleg Victor and Briggs, Andrew and Mol, Jan A. (2017) Field-Effect Control of Graphene–Fullerene Thermoelectric Nanodevices. Nano Letters, 17 (11). pp. 7055-7061. ISSN 1530-6984

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Abstract

Although it was demonstrated that discrete molecular levels determine the sign and magnitude of the thermoelectric effect in single-molecule junctions, full electrostatic control of these levels has not been achieved to date. Here, we show that graphene nanogaps combined with gold microheaters serve as a testbed for studying single-molecule thermoelectricity. Reduced screening of the gate electric field compared to conventional metal electrodes allows control of the position of the dominant transport orbital by hundreds of meV. We find that the power factor of graphene–fullerene junctions can be tuned over several orders of magnitude to a value close to the theoretical limit of an isolated Breit–Wigner resonance. Furthermore, our data suggest that the power factor of an isolated level is only given by the tunnel coupling to the leads and temperature. These results open up new avenues for exploring thermoelectricity and charge transport in individual molecules and highlight the importance of level alignment and coupling to the electrodes for optimum energy conversion in organic thermoelectric materials.

Item Type: Journal Article
Journal or Publication Title: Nano Letters
Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © 2017 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b03736
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/3100/3104
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 88358
Deposited By: ep_importer_pure
Deposited On: 24 Oct 2017 10:12
Refereed?: Yes
Published?: Published
Last Modified: 22 Feb 2020 04:15
URI: https://eprints.lancs.ac.uk/id/eprint/88358

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