1. Department of PhysicsNational University of Singapore Singapore 117551 Singapore
2. Department of ChemistryNational University of Singapore Singapore 117546 Singapore
3. Center for Advanced 2D Materials and Graphene Research Centre Singapore 117546 Singapore
4. NUS Graduate School for Integrative Sciences and EngineeringNational University of Singapore Singapore 117546 Singapore
5. Solar Energy Research Institute of Singapore (SERIS) Singapore 117574 Singapore
6. SZU‐NUS Collaborative Innovation Centre for Optoelectronic Science and TechnologyInternational Collaborative Laboratory of 2D Materials for Optoelectronic Science and Technology of Ministry of EducationCollege of Optoelectronic EngineeringShenzhen University Shenzhen Guangdong 518060 P. R. China