1. Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
2. Beijing Graphene Institute, Beijing 100095, P. R. China
3. Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, P. R. China
4. National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Integrated Circuit, Peking University, Beijing 100871, P. R. China
5. Key Laboratory of Opto-Electronics Technology Ministry of Education College of Electronic Science and Technology Faculty of Information Technology, Beijing University of Technology, Beijing 100024, P. R. China
6. College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, P. R. China
7. School of Electronics, Peking University, Beijing 100871, P. R. China
8. School of Materials Science and Engineering, Peking University, Beijing 100871, P. R. China