1. Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland
2. Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf CH-8600, Switzerland
3. NCCR Catalysis, Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland