Two sets of aromatic nanoribbons, based around a common hexagonal scaffolding, with single and dual terminal amine groups have been considered as potential molecular wires in a junction formed by gold leads. Charge transport through the two-terminal device has been modeled using density functional theory (with and without self-interaction correction) and the nonequilibrium Green's function method. The effects of wire length, multiple terminal contacts, and pathways across the junction have been investigated. For nanoribbons with the oligopyrene motif and conventional single amine terminal groups, an increase in the wire length causes an exponential drop in the conductance. In contrast, for the nanoribbons with the oligoperylene motif and dual amine anchoring groups the predicted conductance rises with the wire length over the whole range of investigated lengths. Only when the effects of self-interaction correction are taken into account, the conductance of the oligoperylene ribbons exhibits saturation for longer members of the series. The oligoperylene nanoribbons, with dual amine groups at both terminals, show the potential to fully harness the highly conjugated system of π molecular orbitals across the junction. © 2012 American Physical Society.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): FIC/2010/08
Acknowledgements: This work was supported by the Flexible Electronics Theme of the CSIRO Future Manufacturing Flagship. A.B. thanks the CSIRO for support through the Julius Career Award. The use of the NCI National Facility supercomputers at the ANU is gratefully acknowledged. The SMEAGOL project is sponsored by Science Foundation of Ireland (Grant No. 07/IN/I945), by KAUST (FIC/2010/08) and by CRANN.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.