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Molecular diodes with rectification ratios exceeding 10(5) driven by electrostatic interactions

TitleMolecular diodes with rectification ratios exceeding 10(5) driven by electrostatic interactions
Publication TypeJournal Article
Year of Publication2017
AuthorsChen, Xiaoping, Roemer Max, Yuan Li, Du Wei, Thompson Damien, del Barco Enrique, and Nijhuis Christian A.
JournalNat. Nanotechnol.
Volume12
Pagination797–803
Date Published08/2017
ISSN1748-3387
Keywordsdesign, energetics, interfaces, metal, rectifiers, self-assembled monolayers, single-molecule, Transport, tunnel-junctions
Abstract

Molecular diodes operating in the tunnelling regime are intrinsically limited to a maximum rectification ratio R of similar to 10(3). To enhance this rectification ratio to values comparable to those of conventional diodes (R {\textgreater}= 10(5)) an alternative mechanism of rectification is therefore required. Here, we report a molecular diode with R = 6.3 x 10(5) based on self-assembled monolayers with Fc-C=C-Fc (Fc, ferrocenyl) termini. The number of molecules (n(V)) involved in the charge transport changes with the polarity of the applied bias. More specifically, n(V) increases at forward bias because of an attractive electrostatic force between the positively charged Fc units and the negatively charged top electrode, but remains constant at reverse bias when the Fc units are neutral and interact weakly with the positively charged electrode. We successfully model this mechanism using molecular dynamics calculations.

DOI10.1038/NNANO.2017.110

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