1. Energy Research Institute@; NTU (ERI@N); Research Techno Plaza, Level 5, 50 Nanyang Drive Singapore 639798 Singapore
2. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; NTU; 21 Nanyang Link Singapore 637371 Singapore
3. Institute of Materials Research and Engineering (IMRE); 3 Research Link Singapore 117602 Singapore
4. School of Material Science and Engineering; NTU; Block N4.1, Nanyang Avenue Singapore 639798 Singapore