1. Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; 21 Nanyang Link 637371 Singapore
2. School of Chemistry and Chemical Engineering and Key Laboratory of Colloid and Interface Chemistry of Ministry of Education; Shandong University; Jinan 250100 P. R. China
3. School of Materials Science and Engineering; Nanyang Technological University; 50 Nanyang Avenue 639798 Singapore