1. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Division Solar Energy, Kekuléstraße 5, 12489 Berlin, Germany
2. Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel
3. Theoretical Physics and chemistry of Materials, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
4. Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States