[1
]Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstrasse 2, 79110 Freiburg,
Germany
[2
]Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Strasse
21, 79104 Freiburg, Germany
[3
]Department of Sustainable Systems Engineering (INATECH), University of Freiburg, Georges-Köhler-Allee
103, 79110 Freiburg, Germany