1. Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu 610054 P. R. China
2. School of Automation Engineering University of Electronic Science and Technology of China Chengdu 611731 P. R. China
3. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China
4. School of Physics University of Electronic Science and Technology of China Chengdu 610054 P. R. China
5. Center of Materials Science and Optoelectronics Engineering College of Materials Science and Opto‐Electronic Technology University of Chinese Academy of Sciences Beijing 100049 P. R. China
6. State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
7. Shenzhen Institute for Advanced Study University of Electronic Science and Technology of China Shenzhen 518110 P. R. China