Energy Conversion

Novel thermoelectric materials can be designed by engineering interfaces of nanostructured compound or superlattice materials. We investigate new organic-inorganic nanocomposites that unite the unique benefits of inorganic and organic materials into one hybrid material that could be used for next-generation thermoelectrics. Hybrid materials containing nanowires or nanoparticles are of particular interest. New transport properties arise at these hard/soft interfaces and account for the enhanced thermoelectric transport behavior. Superlattices as well can be tailored to have specific transport properties which are relevant for novel thermoelectric materials. Advanced synchrotron- and lab-based analytics are applied to the study of such materials.

Catalysis may on the one hand provide the key to developing new CO₂ neutral technologies for converting alternative feedstocks, such as biomass, carbon dioxide, and water into fuels and on the other hand replace energy consuming industrial processes. A major goal in catalysis research is the replacement of scarce metals by abundant transition metal ions (TMI) with optimized catalytic properties. Although outstanding progress has been made in the synthesis and understanding of TMI complexes additional spectroscopic knowledge is mandatory to unravel their structure-function relationship. Many TMIs exhibit paramagnetic states as crucial intermediates in catalytic cycles. This renders electron paramagnetic resonance the method of choice to study function determining TMI properties such as e.g. oxidation and spin states, coordination geometry, and interactions with surrounding ligands. To yield this information we employ very high frequency EPR techniques including synchrotron based THz-EPR.

Thin-fim materials such as poly-silicon on glass, perovskites, organic compounds, chalcopyrites, and kesterites are candidates for absorber materials for highly efficient photovoltaic (PV) devices. The research is focused on unravelling the complex interplay between material structure and electronic properties on a nano scale using synchrotron-based characterization such as Photoemission Electron Microscopy (PEEM) or electron paramagnetic resonance (EPR). In addition, we also explore new ways to spectrally convert the sun light and match it to the optimum need of the PV absorber through for instance triplet-triplet upconversion or exciton multiplication.