1. Experimental Physics VI, Julius Maximilians University Würzburg, Am Hubland, 97074 Würzburg, Germany
2. Institute for Applied Physics, Eberhard Karls University Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
3. Institute for Physical and Theoretical Chemistry, Julius Maximilians University Würzburg, Emil-Fischer-Straße 42, 97074 Würzburg, Germany
4. Bavarian Center for Applied Energy Research, Magdalene-Schoch-Straße 3, 97074 Würzburg, Germany