1. Department of Chemistry; University of Rome ''La Sapienza''; p.le Aldo Moro 5 00139 Rome Italy
2. Department of Chemistry; NIS Interdepartmental Center and INSTM Reference Center; University of Turin; via Pietro Giuria 7 10125 Torino Italy
3. C.H.O.S.E. - Center for hybrid and organic solar energy; Department of Electrical Engineering; University of Rome “Tor Vergata”; via del Politecnico 1 00133 Rome Italy