1. IREC
2. Catalonia Institute for Energy Research
3. Barcelona
4. Spain
5. Catalan Institute of Nanoscience and Nanotechnology (ICN2)
6. Universitat de Barcelona
7. Electronic Engineering Department
8. Universitat Politècnica de Catalunya
9. 08034 Barcelona
10. CSIC and The Barcelona Institute of Science and Technology (BIST)
11. 08193 Barcelona
12. ICREA