1. Energy Research Institute (ERI@N); Interdisciplinary Graduate School; Nanyang Technological University, Research Techno Plaza; 50 Nanyang Drive 637553 Singapore
2. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; Nanyang Technological University; 21 Nanyang Link 637371 Singapore
3. Energy Research Institute (ERI@N); Nanyang Technological University; 50 Nanyang Drive 637553 Singapore