1. Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, School of Physics and State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou 510006, China
2. School of Materials, Sun Yat-Sen University, Guangzhou 510275, China
3. State Key Lab of Photovoltaic Science and Technology, Trina Solar, ChangZhou 213031 China
4. Shunde-SYSU Institute for Solar Energy, Beijiao, Shunde 528300, China
5. Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu Province, China