1. Energy Research Institute at; Nanyang Technological University (ERIAN), Research Techno Plaza, X-Frontier Block Level 5; 50 Nanyang Avenue Singapore 637553 Singapore
2. Division of Chemistry and Biological Chemistry; 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