1. Institute of Materials Research and Engineering (IMRE); 2 Fusionopolis Way. Innovis, #08-03 138634 Singapore
2. Department of Chemistry, College of Chemistry and Engineering; Xiamen University; Xiamen Fujian People's Republic of China
3. Department of Materials Science and Engineering; National University of Singapore; 9 Engineering Drive 1 117576 Singapore
4. Singapore Eye Research Institute; 11 Third Hospital Avenue 168751 Singapore