1. Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Alltenberger Strasse 69, A-4040 Linz, Austria
2. School of Science and Technology and CNISM, University of Camerino, Via Madonna delle Carceri 62032 Camerino (MC), Italy
3. Sincrotrone Trieste S.CpA Strada Statale 14 - Km 163.5 in Area Science Park 34012 Basovizza, Trieste, Italy
4. Department of Physics, University of Rome -La Sapienza, P.le Aldo Moro, Italy
5. LNF-INFN Via Enrico Fermi, 40 00044 Frascati (RM), Italy
6. CNR-ISM, Via del Fosso del Cavaliere, 100 - 00133 Roma, Italy