Berlin 2015 – scientific programme

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DS: Fachverband Dünne Schichten

DS 39: Poster Session II

DS 39.6: Poster

Thursday, March 19, 2015, 16:00–18:30, Poster F

Electron-impact induced HF elimination in fluorinated PAHs: Molecular building blocks for new carbon nanostructures — •Jürgen Weippert¹, Seyithan Ulas¹, Patrick Weis¹, Jean-Francois Greisch², Konstantin Y. Amsharov³, 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 — ³University Erlangen-Nürnberg, Institut für Organische Chemie, Henkestr. 42, 91054, Germany

Electron-impact induced HF-elimination (EIIHF) from fluorinated PAHs (F-PAHs) has been used to create curved molecular carbon structures which cannot be accessed synthetically. We have studied this process using three F-PAHs: C₂₆H₁₄F₂, C₃₆H₁₅F₃ and C₆₀H₂₁F₉. The products of the sequential EIIHF (C₂₆H₁₂⁺, C₃₆H₁₂⁺ and C₆₀H₁₂⁺) have been deposited mass-selectively onto HOPG substrate and their electronic, thermodynamic and vibrational properties analysed by means of UPS, XPS, AFM, TDS and Raman spectroscopy. For all studied molecules HF-elimination is the major fragmentation channel. In contrast to large planar C₆₀H₂₁F₉ molecules, the smaller precursors were found to be entirely dehydrofluorinated upon 70eV e⁻ impact. The hydrodefluorination of C₆₀H₂₁F₉ molecules stops after the sixth EIIHF-step and the resulting products exhibit molecular structures (caps) of relevance for further (n,m)-selective growth of SWCNT.