1. Linz Institute of Organic Solar Cells (LIOS), Institute of Physical Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria
2. Institute for Chemistry and Technology of Materials, NAWI Graz, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
3. Institute of Applied Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria