title: Monolayer Phases of a Dipolar Perylene Derivative on Au(111) and Surface Potential Build-Up in Multilayers.
abstract: 9-(Bis-p-tert-octylphenyl)-amino-perylene-3,4-dicarboxy anhydride (BOPA-PDCA) is a strongly dipolar molecule representing a group of asymmetrically substituted perylenes that are employed in dye-sensitized solar cells and hold great promise for discotic liquid crystal applications. Thin BOPA-PDCA films with orientated dipole moments can potentially be used to tune the energy-level alignment in electronic devices and store information. To help assessing these prospects, we here elucidate the molecular self-assembly and electronic structure of BOPA-PCDA employing room temperature scanning tunneling microscopy and spectroscopy in combination with ultraviolet and X-ray photoelectron spectroscopies. BOPA-PCDA monolayers on Au(111) exclusively form in-plane antiferroelectric phases. The molecular arrangements, the increase of the average number of molecules per unit cell via ripening, and the rearrangement upon manipulation with the STM tip indicate an influence of the dipole moment on the molecular assembly and the rearrangement. A slightly preferred out-of-plane orientation of the molecules in the multilayer induces a surface potential of 1.2 eV. This resembles the giant surface potential effect that was reported for vacuum-deposited tris(8-hydroxyquinoline)aluminum and deemed applicable for data storage. Notably, the surface potential in the case of BOPA-PDCA can in part be reversibly removed by visible light irradiation.
authors.affiliation: Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin , 12489 Berlin, Germany.|Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Niederhausen
authors.affiliation: Physics & Astronomy Department, Ohio University , Athens, Ohio 45701, United States.
authors.forename: Heath R
authors.initials: HR
authors.lastname: Kersell
authors.affiliation: Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin , 12489 Berlin, Germany.|Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany.
authors.forename: Christos
authors.initials: C
authors.lastname: Christodoulou
authors.affiliation: Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin , 12489 Berlin, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Heimel
authors.affiliation: Max Planck Institut für Polymerforschung , 55128 Mainz, Germany.
authors.forename: Henrike
authors.initials: H
authors.lastname: Wonneberger
authors.affiliation: Max Planck Institut für Polymerforschung , 55128 Mainz, Germany.|Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz , 55128 Mainz, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.affiliation: Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin , 12489 Berlin, Germany.
authors.forename: Jürgen P
authors.initials: JP
authors.lastname: Rabe
authors.affiliation: Physics & Astronomy Department, Ohio University , Athens, Ohio 45701, United States.
authors.forename: Saw-Wai
authors.initials: SW
authors.lastname: Hla
authors.affiliation: Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin , 12489 Berlin, Germany.|Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Koch