1. Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden
2. Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-41296, Sweden
3. Department of Engineering and Physics, Karlstad University, 65188 Karlstad, Sweden
4. Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden