1. Department Organic and Perovskite Photovoltaics Fraunhofer Institute for Solar Energy Systems ISE Heidenhofstraße 2 79110 Freiburg Germany
2. Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
3. Michael Grätzel Center for Mesoscopic Solar Cells Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology 1037 Luoyu Road Wuhan 430074 P. R. China
4. Freiburg Materials Research Center FMF University of Freiburg Stefan‐Meier‐Straße 21 79014 Freiburg Germany