1. Department of Chemistry and Centre for Advanced 2D Materials (CA2DM)National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
2. Department of ChemistryInstitute of Molecular PlusSchool of ScienceTianjin University Tianjin 300072 China
3. Institute of Chemical and Engineering SciencesAgency for Science, Technology and Research (A*STAR) 1 Pesek Road, Jurong Island Singapore 627833 Singapore
4. State Key Laboratory of Pulp and Paper EngineeringSouth China University of Technology Guangzhou 510641 China
5. Institute of Flexible ElectronicsNorthwestern Polytechnical University Xi'an 710072 China