1. Physics Department; Free University of Berlin; Arnimallee 14 14195 Berlin Germany
2. Solar Energy; Helmholtz Zentrum Berlin; Hahn-Meitner Platz 1 14109 Berlin Germany
3. Catalonia Institute for Energy Research (IREC); Jardins de les Dones de Negre 1 08930 Sant Adrià de Besòs Barcelona Spain
4. NEXCIS, Avenue Celestin Coq; PA de Rousset 13790 Rousset France