1. Department of Materials Science and Engineering; Key Laboratory of Polymer Chemistry and Physics of Ministry of Education; College of Engineering; Peking University; Beijing 100871 China
2. Department of Chemistry; Capital Normal University; Beijing 100048 China
3. Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 China
4. State Key Laboratory for Mechanical Behavior of Materials; Xi'an Jiaotong University; Xi'an 710049 China
5. Heeger Beijing Research and Development Center; School of Chemistry and Environment; Beihang University; Beijing 100191 China