1. Beijing
Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
2. CAS
Center for Excellence in Nanoscience, National Center for Nanoscience and Technology (NCNST), Beijing 100190, People’s Republic of China
3. University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
4. Key
Laboratory of Organic Optoelectronics and Molecular Engineering of
Ministry of Education, Chemistry Department, Tsinghua University, Beijing 100084, People’s Republic of China
5. School
of Material Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States