1. Department of Chemistry National University of Singapore 3 Science Drive Singapore 117543 Singapore
2. Department of Electronics and Photonics Institute of High Performance Computing A*STAR (Agency for Science, Technology and Research) 1 Fusionopolis Way, #16‐16 Connexis Singapore 138632 Singapore
3. NUS Graduate School for Integrative Sciences and Engineering National University of Singapore 3 Science Drive Singapore 117543 Singapore
4. NUSNNI‐NanoCore National University of Singapore Singapore 117411 Singapore
5. Physical Measurement Laboratory National Institute of Standards and Technology Gaithersburg MD 20899 USA
6. Centre for Advanced 2D Materials National University of Singapore 6 Science Drive 2 Singapore 117546 Singapore