Structure Formation during Organic Molecular Beam Deposition

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dc.contributor.advisor Schreiber, Frank (Prof. Dr.) Reisz, Berthold 2021-07-21T12:12:37Z 2021-07-21T12:12:37Z 2021-07-21
dc.identifier.uri de_DE
dc.description.abstract Pure and blended thin films of copper phthalocyanine (CuPc), Buckminster fullerene (C60) and coronene (Cor) molecules were deposited in vacuum onto standard silicon wafers and served as model systems for organic layers, as they are applied in organic photovoltaics (OPVs), organic light emitting diodes (OLEDs) and organic field effect transistors (OFETs). The blends were prepared by co-deposition, i.e. simultaneous evaporation of two molecular species. The influence of substrate temperature, deposition rate and mixing on the formation of crystal structures and surface profiles was investigated by various x-ray scattering techniques, as well as by atomic force and scanning electron microscopy. The non-linear formation of surface roughness was observed in real-time during the growth by means of in-situ x-ray reflectivity. Depending on the molecular species, three different growth modes were found: The growth of distinct islands, wetting of the substrate and layer plus island growth. Higher substrate temperatures resulted in larger islands and larger crystalline domains at lower island densities. A similar effect was observed when reducing the deposition rate. Faster diffusion and a lower flux of impinging molecules accounts for the improved molecular self-assembly. Mixing of two molecular species lead to smooth CuPc-C60 blends at room temperature and extremely rough CuPc-C60 blends at 400 K. The domain sizes were significantly reduced in blends and long CuPc needles protruding from the thin film appeared. Although a theoretical description of the structure formation is challenging, the studies have shown that a systematic analysis enables to tailor the physical properties of organic thin films by a suitable choice of growth parameters, which is advantageous for technical applications. en
dc.language.iso en de_DE
dc.publisher Universität Tübingen de_DE
dc.rights ubt-podno de_DE
dc.rights.uri de_DE
dc.rights.uri en
dc.subject.ddc 500 de_DE
dc.subject.ddc 530 de_DE
dc.subject.other organic semiconductors en
dc.subject.other thin films en
dc.subject.other vacuum en
dc.subject.other x-ray diffraction en
dc.subject.other scanning electron microscopy en
dc.subject.other atomic force microscopy en
dc.title Structure Formation during Organic Molecular Beam Deposition en
dc.type Dissertation de_DE
dcterms.dateAccepted 2021-05-19
utue.publikation.fachbereich Physik de_DE
utue.publikation.fakultaet 7 Mathematisch-Naturwissenschaftliche Fakultät de_DE
utue.publikation.noppn yes de_DE


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