1. Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, Freiburg 79110, Germany
2. Freiburg Materials Research Center FMF, University of Freiburg, Stefan-Meier-Str. 21, Freiburg 79104, Germany
3. Cluster of Excellence livMatS, University of Freiburg, Georges-Köhler-Allee 105, Freiburg 79110, Germany
4. Zentrum für Sonnenenergie- und Wasserstofforschung Baden-Württemberg (ZSW), Meitnerstraße 1, Stuttgart 70563, Germany
5. Centre for Solar Energy Research (CSER), Centre for Integrative Semiconductor Materials (CISM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales SA1 8EN, U.K.
6. Saule Technologies, Wroclaw Technology Park, 11 Dúnska Str., Sigma building, Wroclaw 54-427, Poland
7. School of Natural and Environmental Science, Bedson Building, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K.