1. Deutsches Museum, Museumsinsel 1, 80538 Munich, Germany, and TUM School of Education, Technical University of Munich, Schellingstrasse 33, 80799 Munich, Germany
2. Center for NanoScience (CeNS), Schellingstrasse 4, 80799 Munich, Germany
3. Department of Chemistry, Ludwig-Maximilians-University, Butenandtstrasse 11 (E), 81377 Munich, Germany