1. Department
of Materials Science and Engineering, College of Engineering, Key
Laboratory of Polymer Chemistry and Physics of Ministry of Education, 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. Heeger
Beijing Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
5. Department
of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong, China
6. National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science
Park, Hsinchu, Taiwan 30076, China