Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Graphene

O 55.13: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-EG

A comparative study of the oxidation of PAHs using atomic oxygen — •Jürgen Weippert¹, Vincent Gewiese¹, Philipp Huber¹, Artur Böttcher¹, and Manfred M. Kappes^1,2 — ¹Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany — ²Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

We have studied the oxidation of PAH films (Coronene, Hexabenzocoronene, Rubrene) as model systems for fabrication of tailored nano-graphene oxides. The corresponding PAH films were grown by low energy ion beam deposition. The as-prepared PAH films were then exposed to a flux of atomic oxygen at room temperature. UPS and XPS based analysis of the chemical composition of the resulting oxidized films reveals a broad spectrum of PAH oxides dominated by epoxy and ether species. The interaction of flat PAHs with the substrate modifies the oxidation pathways in submonolayers cf. multilayers: epoxides are replaced by lactones as the dominating oxide with the exception of non-planar Rubrene. According to theoretical predictions we attribute this specific influence of theHOPG substrate to mobile epoxy functionalities which are produced by reaction of HOPG with incident O atoms. These can approach the adsorbed PAH molecules along the surface * thus destabilizing their molecular rims.