title: Thermal stability and molecular ordering of organic semiconductor monolayers: effect of an anchor group.
abstract: The thermal stability and molecular order in monolayers of two organic semiconductors, PBI-PA and PBI-alkyl, based on perylene derivatives with an identical molecular structure except for an anchor group for attachment to the substrate in PBI-PA, are reported. In situ X-ray reflectivity measurements are used to follow the stability of these monolayers in terms of order and thickness as temperature is increased. Films have thicknesses corresponding approximately to the length of one molecule; molecules stand upright on the substrate with a defined structure. PBI-PA monolayers have a high degree of order at room temperature and a stable film exists up to 250 °C, but decomposes rapidly above 300 °C. In contrast, stable physisorbed PBI-alkyl monolayers only exist up to 100 °C. Above the bulk melting point at 200 °C no more order exists. The results encourage using anchor groups in monolayers for various applications as it allows enhanced stability at the interface with the substrate.
authors.affiliation: Département de Physique, Faculté des Sciences, Université Libre de Bruxelles CP223, Campus de la Plaine, 1050 Brussels (Belgium). andrew.jones@tugraz.at.
authors.forename: Andrew O F
authors.initials: AO
authors.lastname: Jones
authors.affiliation: Macromolecular Chemistry I, University of Bayreuth, 95440 Bayreuth (Germany).
authors.forename: Philipp
authors.initials: P
authors.lastname: Knauer
authors.affiliation: Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria). roland.resel@tugraz.at.
authors.forename: Roland
authors.initials: R
authors.lastname: Resel
authors.affiliation: Macromolecular Chemistry I, University of Bayreuth, 95440 Bayreuth (Germany).|Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven (The Netherlands).
authors.forename: Andreas
authors.initials: A
authors.lastname: Ringk
authors.affiliation: Macromolecular Chemistry I, University of Bayreuth, 95440 Bayreuth (Germany).
authors.forename: Peter
authors.initials: P
authors.lastname: Strohriegl
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmaceutical Sciences, Karl-Franzens Universität Graz, Universitätsplatz 1, 8010 Graz (Austria).
authors.forename: Oliver
authors.initials: O
authors.lastname: Werzer
authors.affiliation: Département de Physique, Faculté des Sciences, Université Libre de Bruxelles CP223, Campus de la Plaine, 1050 Brussels (Belgium).
authors.forename: Michele
authors.initials: M
authors.lastname: Sferrazza
mesh_terms: D018625:Microscopy, Atomic Force; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D012666:Semiconductors; D013499:Surface Properties; D013696:Temperature
chemical_list: D010569:Perylene
keywords: organic semiconductors; perylene bisimide; thermal stability; thin layers; x-ray reflectivity