1. Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
2. National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
3. Department of Chemical Engineering and Materials Science, Department of Physics and Astronomy, University of California—Irvine, Irvine, California 92697, United States
4. Department of Materials Science, Fudan University, Shanghai 200433, China
5. School of Electronics Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China