1. Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), #08-03, 2 Fusionopolis Way, Innovis, 138634 Singapore, Singapore
2. Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, Jianghan University, Wuhan 430056, China
3. Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore