Neue Kohlenstoffnanomaterialien aus massenselektierten molekularen Fragmenten

This work presents the results of various investigations regarding novel carbon nanomaterials. The general strategy to generate these materials was the use of the Low Energy Cluster Beam Deposition method which consists of the ionization and fragmentation of sublimable molecules in the gas phase followed by mass selection and soft-landing of the generated fragment ions on conducting or semiconducting surfaces. Also, the properties
of already existing materials were modified by thermal treatment, doping with alkali metals and oxidation with atomic and molecular oxygen.
This work contains studies concerning the following issues:
- a series of measurements in which the binding energies between polyaromatic hydrocarbons (PAHs) and HOPG were measured by temperature programmed desorption in order to determine the graphite interlayer cohesion energy
- the generation of PAH oligomers by deposition of dehydrogenated PAH fragments
- a comparative study on the reactivity of various PAHs with atomic oxygen and also oxidized HOPG surfaces in order to explore the mediating role of these surfaces
- an investigation of the efficiency and side reactions of the HF limination from fluorinated PAHs which are designed as precursors to generate curved nanostructures from planar molecules
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- attempts to purify single-walled carbon nanotubes by removing tensides or polymer coatings using thermal treatment and oxidation with atomic and molecular oxygen
- the direct confirmation of covalent bonds between non-IPR fullerene cages by observing the sublimation of dimers
- measurements on the properties of Cs doped non-IPR fullerene solids
The properties of the generated materials were characterized using standard UHV methods of surface science: photoelectron spectroscopy, temperature programmed desorption, Raman spectroscopy as well as various microscopic methods.