1. School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
2. Institute of Artificial Photosynthesis State Key Laboratory of Fine Chemicals, Dalian University of Technology 2 Ling Gong Road Dalian 116024 P. R. China
3. Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
4. Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore