1. Department of Physics, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
2. Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
3. Sorbonne Université, CNRS, Institut des NanoSciences de Paris (INSP), 4 Place Jussieu, 75005 Paris, France