1. School of Chemistry; Beihang University; No. 37 Xueyuan Road Beijing 100191 P. R. China
2. CAS Key Laboratory of Nanosystem and Hierarchical Fabrication; CAS Center for Excellence in Nanoscience; National Center for Nanoscience and Technology; Beijing 100190 P. R. China
3. Biomolecular and Organic Electronics; IFM Linköping University; SE-581 83 Linköping Sweden
4. Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices; Institute of Functional Nano and Soft Materials (FUNSOM); Soochow University; Suzhou 215123 Jiangsu Province P. R. China