title: Switchable Charge Injection Barrier in an Organic Supramolecular Semiconductor.
abstract: We disclose a supramolecular material that combines semiconducting and dipolar functionalities. The material consists of a discotic semiconducting carbonyl-bridged triarylamine core, which is surrounded by three dipolar amide groups. In thin films, the material self-organizes in a hexagonal columnar fashion through π-stacking of the molecular core and hydrogen bonding between the amide groups. Alignment by an electrical field in a simple metal/semiconductor/metal geometry induces a polar order in the interface layers near the metal contacts that can be reversibly switched, while the bulk material remains nonpolarized. On suitably chosen electrodes, the presence of an interfacial polarization field leads to a modulation of the barrier for charge injection into the semiconductor. Consequently, a reversible switching is possible between a high-resistance, injection-limited off-state and a low-resistance, space-charge-limited on-state. The resulting memory diode shows switchable rectification with on/off ratios of up to two orders of magnitude. This demonstrated multifunctionality of a single material is a promising concept toward possible application in low-cost, large-area, nonvolatile organic memories.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Gorbunov
authors.forename: Andreas T
authors.initials: AT
authors.lastname: Haedler
authors.affiliation: Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, KU Leuven , Celestijnenlaan 200D, B-3001 Heverlee, Belgium.
authors.forename: Tristan
authors.initials: T
authors.lastname: Putzeys
authors.forename: R Helen
authors.initials: RH
authors.lastname: Zha
authors.affiliation: Makromolekuläre Chemie I, Bayreuther Institut für Makromolekülforschung (BIMF), and Bayreuther Zentrum für Kolloide und Grenzflächen (BZKG), Universität Bayreuth , 95440 Bayreuth, Germany.
authors.forename: Hans-Werner
authors.initials: HW
authors.lastname: Schmidt
authors.affiliation: Lehrstuhl für Organische Chemie I, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany.
authors.forename: Milan
authors.initials: M
authors.lastname: Kivala
authors.affiliation: Complex Materials and Devices, Department of Physics, Chemistry and Biology (IFM), Linköping University , 58183 Linköping, Sweden.
authors.forename: Indre
authors.initials: I
authors.lastname: Urbanavičiu̅tė
authors.affiliation: Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, KU Leuven , Celestijnenlaan 200D, B-3001 Heverlee, Belgium.
authors.forename: Michael
authors.initials: M
authors.lastname: Wübbenhorst
authors.forename: E W
authors.initials: EW
authors.lastname: Meijer
authors.affiliation: Complex Materials and Devices, Department of Physics, Chemistry and Biology (IFM), Linköping University , 58183 Linköping, Sweden.
authors.forename: Martijn
authors.initials: M
authors.lastname: Kemerink
keywords: current switching; dipolar switching; injection barrier; memories; organic semiconductors; polarization; rectification