Orbital redistribution in molecular nanostructures mediated by metal-organic bonds
Yang, Zechao (Freie Universität Berlin. Institut für Experimentalphysik)
Corso, Martina (Centro de Física de Materiales CSIC)
Robles, Roberto (Institut Català de Nanociència i Nanotecnologia)
Lotze, Christian (Freie Universität Berlin. Institut für Experimentalphysik)
Fitzner, Roland (Universität Ulm. Institut für Organische Chemie II und Neue Materialien)
Mena-Osteritz, Elena (Universität Ulm. Institut für Organische Chemie II und Neue Materialien)
Bäuerle, Peter (Universität Ulm. Institut für Organische Chemie II und Neue Materialien)
Franke, Katharina J. (Freie Universität Berlin. Institut für Experimentalphysik)
Pascual, José I. (CIC NanoGUNE)

Date:	2014
Abstract:	Dicyanovinyl-quinquethiophene (DCV5T-Me) is a prototype conjugated oligomer for highly efficient organic solar cells. This class of oligothiophenes are built up by an electron-rich donor (D) backbone and terminal electron-deficient acceptor (A) moieties. Here, we investigated its structural and electronic properties when it is adsorbed on a Au(111) surface using low temperature scanning tunneling microscopy/spectroscopy (STM/STS) and atomic force microscopy (AFM). We find that DCV5T-Me self-assembles in extended chains, stabilized by intercalated Au atoms. The effect of metal-ligand hybridization with Au adatoms causes an energetic downshift of the DCV5T-Me lowest unoccupied molecular orbital (LUMO) with respect to the uncoordinated molecules on the surface. The asymmetric coordination of a gold atom to only one molecular end group leads to an asymmetric localization of the LUMO and LUMO+1 states at opposite sides. Using model density functional theory (DFT) calculations, we explain such orbital reshaping as a consequence of linear combinations of the original LUMO and LUMO+1 orbitals, mixed by the attachment of a bridging Au adatom. Our study shows that the alignment of molecular orbitals and their distribution within individual molecules can be modified by contacting them to metal atoms in specific sites.
Grants:	Ministerio de Economía y Competitividad MAT2012-38318-C03-02 Ministerio de Economía y Competitividad MAT2013-46593-C6-01
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Published in:	ACS nano, Vol. 8, Issue 10 (October 2014) , p. 10715-10722, ISSN 1936-086X

DOI: 10.1021/nn504431e

preprint 22 p, 6.8 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles