1. Institute for Solar Energy Systems Guangdong Provincial Key Laboratory of Photovoltaic Technology School of Physics Sun Yat‐sen University Guangzhou 510006 P. R. China
2. IEK5‐Photovoltaik Forschungszentrum Jülich 52425 Jülich Germany
3. Faculty of Engineering and CENIDE University of Duisburg‐Essen Carl‐Benz‐Str. 199 47057 Duisburg Germany