1. School
of Chemical and Biomedical Engineering, Nanyang Technological University, Block N1.2, 62 Nanyang Drive, Singapore 637459, Singapore
2. Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China
3. National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan, Republic of China
4. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore