1. Catalonia Institute for Energy Research−IREC, 08930 Sant Adrià de Besòs, Barcelona, Spain
2. LENS-MIND, Departament d’Enginyeria Electrònica I Biomèdica, Universitat de Barcelona, 08028 Barcelona, Spain
3. Institute of Nanoscience and Nanotechnology (In2UB), Universitat de Barcelona, 08028 Barcelona, Spain
4. Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, 16130 Genova, Italy
5. Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
6. ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain