1. Institute of Nanotechnology, Karlsruhe Institute of Technology, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
2. Department of Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
3. Center for Materials Research, Justus Liebig University, Giessen, Germany
4. Light Technology Institute, Karlsruhe Institute of Technology, Engesserstr. 13, 76131 Karlsruhe, Germany
5. Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften, Philipps University Marburg, Hans-Meerwein-Straße 4, 35043 Marburg, Germany