1. Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, School of Physics, Sun Yat-Sen University, Guangzhou, Guangdong Province 510006, China
2. School of Materials, Sun Yat-Sen University, Shenzhen, Guangdong Province 518107, China
3. Instrumental Analysis & Research Center, Sun Yat-sen University, Guangzhou, Guangdong Province 510275, China
4. Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou, Jiangsu Province 213164, China