1. Division of Nanophotonics; CAS Key Laboratory of Standardization and Measurement for Nanotechnology; CAS Center for Excellence in Nanoscience; National Center for Nanoscience and Technology; Beijing 100190 P. R. China
2. Center for Nanochemistry (CNC); Beijing Science and Engineering Center for Nanocarbons; Beijing National Laboratory for Molecular Sciences; College of Chemistry and Molecular Engineering; Academy for Advanced Interdisciplinary Studies; Peking University; Beijing 100871 P. R. China
3. Department of Materials Science and Engineering; College of Engineering; Peking University; Beijing 100871 P. R. China