title: Scanning tunneling microscopy and spectroscopy of donor-acceptor-donor triads at the liquid/solid interface.
abstract: By means of scanning tunneling microscopy (STM), the self-assembly of two organic donor-acceptor-donor triads (donor=oligo(p-phenylene vinylene) (OPV); acceptor=perylene diimide (PDI)) and their mixtures has been investigated at the liquid/solid interface. Both triads differ in the nature of the substituents and, therefore, in the redox properties of the central perylene diimide unit (H or Cl). Thanks to the submolecular resolution, the distinct electronic properties of the units, within a triad and between the two triads, are reflected by the relative STM contrast in the bias-dependent imaging experiments. Moreover, scanning tunneling spectroscopy reveals an inverse rectifying behavior of the OPV and H-substituted PDI units, which is discussed in the framework of quasi-resonant tunneling. A striking difference is observed for the Cl-substituted triad.
authors.affiliation: Katholieke Universiteit Leuven, Department of Chemistry, Molecular and Nano Materials, Laboratory of Photochemistry and Spectroscopy, Celestijnenlaan 200 F, 3001 Leuven, Belgium.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uji-I
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miura
authors.forename: Albert
authors.initials: A
authors.lastname: Schenning
authors.forename: E W
authors.initials: EW
authors.lastname: Meijer
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Chen
authors.forename: Frank
authors.initials: F
authors.lastname: Würthner
authors.forename: Frans C
authors.initials: FC
authors.lastname: De Schryver
authors.forename: Mark
authors.initials: M
authors.lastname: Van der Auweraer
authors.forename: Steven
authors.initials: S
authors.lastname: De Feyter