1. Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
2. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
3. Institute of Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
4. Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
5. Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, People’s Republic of China
6. Institut für Physik und Astronomie, Universität Potsdam, 14776 Potsdam, Germany
7. Photophysics & OptoElectronics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, The Netherlands