1. Agency for Science, Technology and Research (A*STAR) Institute of Materials Research and Engineering (IMRE) 2 Fusionopolis Way, Innovis #08‐03 Singapore 138634 Singapore
2. Agency for Science, Technology and Research (A*STAR) Institute of Sustainability for Chemicals, Energy and Environment (ISCE2) 1 Pesek Road, Jurong Island Singapore 627833 Singapore
3. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
4. Department of Physics National University of Singapore 2 Science Drive 3 Singapore 117551 Singapore
5. Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
6. School of Chemistry, Chemical Engineering and Biotechnology Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore