1. Division PhotovoltaicsFraunhofer Institute for Solar Energy Systems Heidenhofstraße 2 79110 Freiburg Germany
2. Institute of Inorganic and Analytical ChemistryUniversity of Freiburg 79104 Freiburg Germany
3. Institute of Physics and AstronomyUniversity of Potsdam 14476 Potsdam Germany
4. Young Investigator Group Perovskite Tandem Solar CellsHelmholtz-Zentrum Berlin für Materialien und Energie GmbH Kekuléstraße 5 Berlin 12489 Germany
5. Laboratory for Photovoltaic Energy Conversion, Department for Sustainable Systems Engineering (INATECH)University of Freiburg 79110 Freiburg Germany