1. Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern 3012, Switzerland
2. Laboratory of Thin Films and Photovoltaics, Empa—Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, Dübendorf 8600, Switzerland
3. Wood Materials Science, Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, Zürich 8093, Switzerland
4. Nanoscale Materials Science, Empa—Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland