[1] Catalonia Inst Energy Res IREC, E-08930 St Adria Del Besos, Spain
[2] Univ Barcelona, Dept Elect, E-08028 Barcelona, Spain
[3] ICMAB CSIC, Inst Ciencia Mat Barcelona, E-08193 Bellaterra, Spain
[4] ICREA, E-08010 Barcelona, Spain
[5] Moscow MV Lomonosov State Univ, Dept Chem, Moscow 119991, Russia
[6] Univ Cologne, Inst Inorgan Chem, D-50939 Cologne, Germany