1. Linz Institute for organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University Linz, Altenberger Str. 69, Linz A4040, Austria
2. Fachhochschule Wels, Rosegger Str. 12, Wels A-4600, Austria
3. Solid State Physics, Johannes Kepler University Linz, Altenberger Str. 69, Linz A4040, Austria