Electrical molecular switch addressed by chemical stimuli

We demonstrate that the conductance switching of benzo-bis(imidazole) molecules upon protonation depends on the lateral functional groups. The protonated H-substituted molecule shows a higher conductance than the neutral one ( G pro > G neu ), while the opposite ( G neu > G pro ) is observed f...

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Bibliographic Details
Published in:Nanoscale 2020-05, Vol.12 (18), p.1127-1139
Main Authors: Audi, H, Viero, Y, Alwhaibi, N, Chen, Z, Iazykov, M, Heynderickx, A, Xiao, F, Guérin, D, Krzeminski, C, Grace, I. M, Lambert, C. J, Siri, O, Vuillaume, D, Lenfant, S, Klein, H
Format: Article
Language:English
Subjects:
Electrical junctions
Electron transport
Functional groups
Imidazole
Mathematical analysis
Molecular machines
Molecular orbitals
NMR
Nuclear magnetic resonance
Physics
Protonation
Resistance
Self-assembled monolayers
Self-assembly
Substitutes
X ray photoelectron spectroscopy
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Summary:We demonstrate that the conductance switching of benzo-bis(imidazole) molecules upon protonation depends on the lateral functional groups. The protonated H-substituted molecule shows a higher conductance than the neutral one ( G pro > G neu ), while the opposite ( G neu > G pro ) is observed for a molecule laterally functionalized by amino-phenyl groups. These results are demonstrated at various scale lengths: self-assembled monolayers, tiny nanodot-molecule junctions and single molecules. From ab initio theoretical calculations, we conclude that for the H-substituted molecule, the result G pro > G neu is correctly explained by a reduction of the LUMO-HOMO gap, while for the amino-phenyl functionnalized molecule, the result G neu > G pro is consistent with a shift of the HOMO, which reduces the density of states at the Fermi energy. We demonstrate that the conductance switching of benzo-bis(imidazole) molecules upon protonation depends on the lateral functional groups.
ISSN:2040-3364
2040-3372
DOI:10.1039/d0nr02461a