title: Charged and metallic molecular monolayers through surface-induced aromatic stabilization.
abstract: Large π-conjugated molecules, when in contact with a metal surface, usually retain a finite electronic gap and, in this sense, stay semiconducting. In some cases, however, the metallic character of the underlying substrate is seen to extend onto the first molecular layer. Here, we develop a chemical rationale for this intriguing phenomenon. In many reported instances, we find that the conjugation length of the organic semiconductors increases significantly through the bonding of specific substituents to the metal surface and through the concomitant rehybridization of the entire backbone structure. The molecules at the interface are thus converted into different chemical species with a strongly reduced electronic gap. This mechanism of surface-induced aromatic stabilization helps molecules to overcome competing phenomena that tend to keep the metal Fermi level between their frontier orbitals. Our findings aid in the design of stable precursors for metallic molecular monolayers, and thus enable new routes for the chemical engineering of metal surfaces.
authors: Institut für Physik, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 6, D-12489 Berlin, Germany. georg.heimel@physik.hu-berlin.de
authors: G
authors: G
authors: Heimel
authors: S
authors: S
authors: Duhm
authors: I
authors: I
authors: Salzmann
authors: A
authors: A
authors: Gerlach
authors: A
authors: A
authors: Strozecka
authors: J
authors: J
authors: Niederhausen
authors: C
authors: C
authors: Bürker
authors: T
authors: T
authors: Hosokai
authors: I
authors: I
authors: Fernandez-Torrente
authors: G
authors: G
authors: Schulze
authors: S
authors: S
authors: Winkler
authors: A
authors: A
authors: Wilke
authors: R
authors: R
authors: Schlesinger
authors: J
authors: J
authors: Frisch
authors: B
authors: B
authors: Bröker
authors: A
authors: A
authors: Vollmer
authors: B
authors: B
authors: Detlefs
authors: J
authors: J
authors: Pflaum
authors: S
authors: S
authors: Kera
authors: K J
authors: KJ
authors: Franke
authors: N
authors: N
authors: Ueno
authors: J I
authors: JI
authors: Pascual
authors: F
authors: F
authors: Schreiber
authors: N
authors: N
authors: Koch
mesh_terms: D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D009279:Naphthacenes / Q000737:chemistry*; D011809:Quinones / Q000737:chemistry*; D012666:Semiconductors; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: C468647:6,13-pentacenequinone; D008670:Metals; D009279:Naphthacenes; D011809:Quinones; C523499:pentacene