1. Institute of Photoelectronic Thin Film Devices and Technology and Tianjin Key Laboratory of Thin Film Devices and Technology, Nankai University, Tianjin 300350, P. R. China
2. Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, Jilin, 130022, China
3. Materials Genome Institute, Shanghai University, Shanghai 200444, P. R. China
4. Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Tianjin 300071, China
5. School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, Australia