1. Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern 3012, Switzerland
2. Surface Science and Coating Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland
3. Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf 8600, Switzerland