1. Center for Nanochemistry (CNC)Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringAcademy for Advanced Interdisciplinary StudiesPeking University Beijing 100871 P. R. China
2. State Key Laboratory of Solid‐State LightingInstitute of SemiconductorsChinese Academy of Sciences Beijing 100083 P. R. China
3. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100049 P. R. China
4. Electron Microscopy Laboratory, and International Center for Quantum MaterialsSchool of PhysicsPeking University Beijing 100871 P. R. China
5. Beijing Graphene Institute (BGI) Beijing 100095 P. R. China
6. Collaborative Innovation Centre of Quantum Matter Beijing 100871 P. R. China