1. Division of Physics and Applied Physics; School of Physical and Mathematical Sciences; Nanyang Technological University; 21 Nanyang Link Singapore 637371 Singapore
2. Key Laboratory of Flexible Electronics and Institute of Advanced Materials; Jiangsu National Synergetic Innovation Center for Advanced Materials; Nanjing Tech University; 30 South Puzhu Road Nanjing 211816 China
3. Energy Research Institute @ NTU (ERI@N); Research Techno Plaza X-Frontier Block, Level 5, 50 Nanyang Drive Singapore 637553 Singapore
4. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue Singapore 639798 Singapore
5. Institute of Applied Physics and Materials Engineering; University of Macau; Macao SAR 999078 China