1. Energy Research Institute at Nanyang Technological University (ERI@N); Research Techno Plaza; X-Frontier Block Level 5, 50 Nanyang Drive Singapore 637553 Singapore
2. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; Nanyang Technological University; 21 Nanyang Link Singapore 637371 Singapore
3. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore