1. Department of Physics National University of Singapore Singapore 117542 Singapore
2. Department of Chemistry National University of Singapore Singapore 117543 Singapore
3. Institute of Microelectronics A*STAR (Agency for Science Technology, and Research) 2 Fusionopolis Way Singapore 138634 Singapore
4. Department of Materials Science & Engineering National University of Singapore Singapore 117575 Singapore
5. Institute of Optoelectronic Display National & Local United Engineering Lab of Flat Panel Display Technology Fuzhou University Fuzhou 350002 P. R. China
6. Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
7. State Key Laboratory of Luminescence and Applications Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun Jilin 130033 China
8. National University of Singapore (Suzhou) Research Institute 377 Lin Quan Street, Suzhou Industrial Park Suzhou 215123 P. R. China