Molekulare dünne Schichten und ihre Grenzflächen
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Molecular thin films and their interfaces
Organic devices consist of a multiplicity of organic layers making the understanding of the organic interface and organic-on-organic growth a technologically important issue. On the one hand details of the interfaces are important for charge injection, while on the other hand the molecular/crystallite orientation and film morphology determine charge transport, light emission/absorption. For optimum performance these key factors need to be tailored for the specific device applications as LEDs, FETs and photovoltaics have different requirements. Recently, the role of the various interfaces has become recognised as one, if not the most important parameter impacting on device function.
Controlling the growth of organic films, in terms of morphology as well as crystallite orientation, is both, desirable for the production of organic devices and a prime prerequisite for unambiguous studies of their physical properties. Within this research topic we aim at characterising and controlling the growth of (1) organic thin films on metal and metal-oxide substrates, (2) organic-organic heterostructures and (3) metal (-oxide) layers on organics, from their initial stages of formation up to device relevant dimensions. To achieve this aim we apply a wide range of modern surface science methods that are available either in-house or at synchrotron radiation facilities across Europe. The in-house facilities include scanning tunnelling microscopy (Low temperature and variable temperature up to 600 K), a photo-emission-electron-microscope in combination with a scanning force microscope, angle resolved UV spectrometers for probing the molecular electronic structure and X-ray photoemission to investigate the interfacial chemistry. Currently all systems are prepared and studied in-situ in ultra-high vacuum.