Interface Characteristics At An Organic/Metal Junction: Pentacene On Cu Stepped Surfaces

Keywords

density functional theory; pentacene; van der Waals; vicinal surfaces

Abstract

The adsorption of pentacene on Cu (2 2 1), Cu (5 1 1) and Cu (9 1 1) is investigated using density functional theory (DFT) with the self-consistent inclusion of van der Waals (vdW) interactions. Cu (2 1 1) is a vicinal of Cu (1 1 1) while Cu (5 1 1) and (9 1 1) are vicinals of Cu (1 0 0). For all the three surfaces, we found pentacene to prefer to adsorb parallel to the surface and near the steps. The addition of vdW interactions resulted in an enhancement in adsorption energies, with reference to the PBE functional, of around 2 eV. With vdWs inclusion, the adsorption energies were found to be 2.98 eV, 3.20 eV and 3.49 eV for Cu (2 2 1), Cu (5 1 1) and Cu (9 1 1) respectively. These values reflect that pentacene adsorbs stronger on (1 0 0) terraces with a preference for larger terraces. The molecule tilts upon adsorption with a small tilt angle on the (1 0 0) vicinals (about a few degrees) as compared to a large one on Cu (2 2 1) where the tilt angle is found to be about 20°. We find that the adsorption results in a net charge transfer to the molecule of ∼1 electron, for all surfaces.

Publication Date

9-8-2016

Publication Title

Journal of Physics Condensed Matter

Volume

28

Issue

44

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1088/0953-8984/28/44/445001

Socpus ID

84988982133 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84988982133

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