Das Projekt "Structured Templates of (6,6)-Phenyl C61-Butyric Acid Methyl Ester (PCBM) for Applications in Photovoltaics and Photonics" wird vom Umweltbundesamt gefördert und von Eidgenössische Materialprüfungs- und Forschungsanstalt durchgeführt. We present a new strategy for controlling organic thin film morphologies that can find use in photovoltaics and photonics. The ability to control the thin film morphology of organic semiconducting materials on different length scales will determine the usefulness of this class of materials in future opto-electronic devices. Structuring on the micron to sub-micron level is of interest for photonic effects. The morphology and phase separation on the 10-20 nm scale in binary materials critically determines device performance in organic photovoltaic cells. Furthermore, the control of the arrangement of organic molecules on a molecular level has proven to be crucial, both for electronic transport properties as well as for optical properties. A demixing process where the lateral size of the phase structure can be controlled over more than two orders of magnitude is liquid-liquid dewetting (LLD). In LLD, a blend solution phase separates into a transient bilayer, followed by destabilization of the layers via an interfacial disjoining pressure. Films spin coated from PCBM/cyanine dye mixtures phase separate by LLD. The mechanism results in a large variety of phase morphologies and, in particular, self-similar phase structures with dimensions ranging from 5 micron to well below 50 nm in a controllable fashion. Moreover, in this materials system, LLD induces a specific 2-dimensional arrangement of dye molecules on PCBM surfaces, most impressively demonstrated by enormous changes in the dye absorption characteristics (H-aggregation). The combination of length scale control in the superordinated phase structure with the initiation of molecular order (aggregation) gives LLD unique attributes and potential. In this project, we propose to use the liquid-liquid dewetting process for the manufacturing of stabilized, in-soluble scaffolds of PCBM by selectively removing the dye. Long range order can be induced through surface energy patterning. We want to address issues related to solvent stability, long-range order and infiltration properties of PCBM templates, knowledge which is necessary to make full use of the potential of PCBM templates. Applications of these templates are manifold, ranging from screening of donor materials for organic solar cells to photonic structures for all-optical switching elements