Hydrogen bonding as the origin of the switching behavior in dithiolated phenylene-vinylene oligomers
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Obodo, Tobechukwu Joshua
Gkionis, Konstantinos
Rungger, Ivan
Sanvito, Stefano
Schwingenschlögl, Udo

KAUST Department
Computational Physics and Materials Science (CPMS)Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2013-08-29Permanent link to this record
http://hdl.handle.net/10754/315779
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We investigate theoretically the switching behavior of a dithiolated phenylene-vinylene oligomer sandwiched between Au(111) electrodes using self-interaction corrected density-functional theory combined with the nonequilibrium Green's-function method for quantum transport. The molecule presents a configurational bistability, which can be exploited in constructing molecular memories, switches, and sensors. We find that protonation of the terminating thiol groups is at the origin of the change in conductance. H bonding at the thiol group weakens the S-Au bond and reduces by about one order of magnitude the transmission coefficient at the Fermi level, and thus the linear response conductance. Furthermore, protonation downshifts in energy the position of the highest occupied molecular orbital, so that the current of the protonated species is lower than that of the unprotonated one along the entire bias range investigated, from −1.5 to 1.5 V. A second protonation at the opposite thiol group has only minor effects and no further drastic reduction in transmission takes place. Our results allow us to re-interpret the experimental data originally attributing the conductance reduction to H dissociation.Citation
Obodo JT, Gkionis K, Rungger I, Sanvito S, Schwingenschlögl U (2013) Hydrogen bonding as the origin of the switching behavior in dithiolated phenylene-vinylene oligomers. Phys Rev B 88. doi:10.1103/PhysRevB.88.085438.Publisher
American Physical Society (APS)Journal
Physical Review BAdditional Links
http://link.aps.org/doi/10.1103/PhysRevB.88.085438ae974a485f413a2113503eed53cd6c53
10.1103/PhysRevB.88.085438