1. IEK-5 Photovoltaik, Forschungszentrum Jülich, 52425 Jülich, Germany.
2. Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum-Berlin, 14109 Berlin, Germany.
3. Faculty of Engineering and CENIDE, University of Duisburg-Essen, 47057 Duisburg, Germany.