1. Energy Research Institute @ NTU (ERI@N); Interdisciplinary Graduate School; Nanyang Technological University; Singapore 637553 Singapore
2. School of Materials Science and Engineering; Nanyang Technological University; Singapore 639798 Singapore
3. Institute of Materials Research and Engineering; A*STAR (Agency for Science, Technology and Research); 2 Fusionopolis Way Innovis #08-03 Singapore 138634 Singapore