1. IBM Research−Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
2. Optical Materials Engineering Laboratory, ETH Zürich, 8092 Zürich, Switzerland
3. School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF243AA, United Kingdom
4. Institute of Inorganic Chemistry, Department of Chemistry and Applied Bioscience, ETH Zürich, 8093 Zürich, Switzerland
5. Laboratory of Thin Films and Photovoltaics, Empa − Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
6. Cardiff University School of Biosciences, Museum Avenue, Cardiff CF10 3AX, United Kingdom