1. Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry; Chinese Academy of Sciences (ICCAS); Beijing 100190 P. R. China
2. Heeger Beijing Research and Development Center; Beihang University; Beijing 100191 P. R. China
3. Department of Chemistry and Biochemistry, Department of Physics, Materials Department; University of California; Santa Barbara CA 93106 USA