1. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue 639798 Singapore Singapore
2. Eco-materials and Renewable Energy Research Center (ERERC), College of Engineering and applied Science; Nanjing University; Nanjing 210093 P.R. China
3. School of Physical and Mathematical Sciences; Nanyang Technological University; 637371 Singapore Singapore
4. Singapore Institute of Manufacturing Technology; 71 Nanyang Drive Singapore 638075