1. School of Chemistry, University of Edinburgh, Kings Buildings, Edinburgh, EH9 3JJ, UK
2. Saule Research Institute, Wroclaw PL 54-130, Poland
3. Faculty of Materials Engineering and Technical Physics, Poznan University of Technology Piotrowo 3, 60-965 Poznan, Poland
4. Department of Semiconductor Materials Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
5. Saule Technologies, Wroclaw PL 54-427, Poland
6. Organic Semiconductor Centre, School of Physics and Astronomy, SUPA, University of St Andrews, St Andrews, KY16 9SS, UK