1. Department of Chemistry; Lab. ITODYS; University Paris Diderot; 15 rue Jean-Antoine de Baïf 75205 Paris cedex 13 France
2. Eurecat; Technology Centre of Catalonia; Av. Ernest Lluch, 36 08302 Mataró Spain
3. Centre de Nanosciences et de Nanotechnologies; University Paris Sud; CNRS UMR 8622 - IEF 91405 Orsay France
4. Department of Electrical and Electronical Engineering (DIEE); University of Cagliari; Via Marengo 3 09123 Cagliari Italy