1. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
2. Organic Semiconductor Research Center, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
3. Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310058, Zhejiang, China
4. Department of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong 999077, China