1. State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China
2. School of Applied Chemistry and Engineering University of Science and Technology of China Hefei 230026 P. R. China
3. Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China
4. Key Laboratory of UV‐Emitting Materials and Technology Northeast Normal University Ministry of Education Changchun 130024 P. R. China