[1] ASTAR, Inst Mat Res Engn, Singapore 117602, Singapore
[2] Natl Univ Singapore, Dept Chem & Biomol Engn, Singapore 117585, Singapore
[3] Hong Kong Univ Sci & Technol, Dept Chem, Div Biomed Engn, Kowloon, Hong Kong, Peoples R China
[4] Natl Univ Singapore, Dept Chem, Singapore 117543, Singapore
[5] Nanyang Technol Univ, Div Chem & Biol Chem, Singapore 637371, Singapore
[6] S China Univ Technol, SCUT HKUST Joint Res Lab, Guangdong Innovat Res Team, State Key Lab Luminescent Mat & Devices, Guangzhou 510640, Guangdong, Peoples R China