1. Department of Chemistry, University of Patras, GR-26504 Patras, Greece
2. Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, GR-15310 Agia Paraskevi Attiki, Greece
3. Departament de Quimica Inorganica and Institut de Nanociencia
i Nanotecnologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain