1. Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir Prelog Weg 1, CH-8093 Zurich, Switzerland
2. Empa−Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
3. Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092 Zurich, Switzerland
4. Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland