1. Department of Materials Science and Engineering City University of Hong Kong Hong Kong SAR 999077 P. R. China
2. Centre for Advanced Structural Materials Shenzhen Research Institute City University of Hong Kong Shenzhen 518057 P. R. China
3. Joint Laboratory of Graphene Materials and Applications State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 P. R. China
4. Energy Materials Research Center AG Hydrogen Materials & Devices CAS Key Laboratory of Materials for Energy Conversion Shanghai Institute of Ceramics Chinese Academy of Sciences (SICCAS) Shanghai 200050 P. R. China
5. State Key Laboratory of Terahertz and Millimeter Waves City University of Hong Kong Hong Kong SAR 999077 P. R. China
6. Key Laboratory of Advanced Materials Processing & Mold Zhengzhou University Ministry of Education Zhengzhou 450002 P. R. China