Two-dimensional core–shell donor–acceptor assemblies at metal–organic interfaces promoted by surface-mediated charge transfer. Issue 45 (3rd November 2016)

• Record Type: Journal Article
• Authors: Della Pia, A.; Riello, M.; Stassen, D.; Jones, T. S.; Bonifazi, D.; De Vita, A.; Costantini, G.
• Is Part Of: Nanoscale. Volume 8:Issue 45(2016)
• Page Start: 19004
• Page End: 19013
• Publication Date: 2016-11-03
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c6nr06527a
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Unprecedented core–shell supramolecular architectures, enabled by a surface mediated charge transfer between electron donors and acceptors molecules are revealed by a combined experimental and theoretical investigation. Abstract : Organic charge transfer (CT) complexes obtained by combining molecular electron donors and acceptors have attracted much interest due to their potential applications in organic opto-electronic devices. In order to work, these systems must have an electronic matching – the highest occupied molecular orbital (HOMO) of the donor must couple with the lowest unoccupied molecular orbital (LUMO) of the acceptor – and a structural matching, so as to allow direct intermolecular CT. Here it is shown that, when molecules are adsorbed on a metal surface, novel molecular organizations driven by surface-mediated CT can appear that have no counterpart in condensed phase non-covalent assemblies of donor and acceptor molecules. By means of scanning tunneling microscopy and spectroscopy it is demonstrated that the electronic and self-assembly properties of an electron acceptor molecule can change dramatically in the presence of an additional molecular species with marked electron donor character, leading to the formation of unprecedented core–shell assemblies. DFT and classical force-field simulations reveal that this is a consequence of charge transfer from the donor to the acceptor molecules mediated by the metallic substrate.