1. Institute for Solar Energy Systems Guangdong Provincial Key Laboratory of Photovoltaic Technology School of Physics Sun Yat-sen University 510006 Guangzhou P. R. China
2. IEK-5 Photovoltaik Forschungszentrum Jülich Leo-Brandt-Straße 52425 Jülich Germany
3. R&D Centre Jinko Solar Holding Co. Ltd. Yuanhua Town 314416 Haining P. R. China
4. Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering Changzhou University No. 1 Gehu Road 213164 Changzhou P. R. China