1. Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Bioscience, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
2. Laboratory for Thin Films and Photovoltaics, Empa—Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
3. Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
4. Center for Nanoscale Materials, Argonne National Laboratory, 9700 Cass Avenue, Lemont, Illinois 60439, United States