1. Institute of Inorganic Chemistry Department of Chemistry and Applied Biosciences ETH Zürich Zurich CH‐8093 Switzerland
2. Laboratory for Thin Films and Photovoltaics Empa ‐ Swiss Federal Laboratories for Materials Science and Technology Dubendorf CH‐8600 Switzerland
3. Univ Rennes ENSCR CNRS ISCR – UMR6226 Rennes F‐35000 France
4. Univ Rennes INSA Rennes CNRS Institut FOTON – UMR6082 Rennes F‐35000 France