1. Key
Laboratory of Polar Materials and Devices (Ministry of Education), East China Normal University, Shanghai, 200241, Peoples’ Republic of China
2. Wright
Center for Photovoltaics Innovation and Commercialization, the University of Toledo, Toledo, Ohio 43606, United States
3. Shanghai Center for Photovoltaics (SCPV), Shanghai, 200081, Peoples’ Republic of China
4. National
Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, the Chinese Academy of Sciences, Shanghai, 200081, Peoples’ Republic of China