1. Department of Chemistry and Energy Institute; The Hong Kong University of Science and Technology; Clear Water Bay Kowloon Hong Kong
2. Department of Physics and Organic and Carbon Electronics Laboratory (ORaCEL); North Carolina State University; Raleigh NC 27695 USA
3. Institute of Polymer Optoelectronic Materials and Devices; State Key Laboratory of Luminescent Materials and Devices; South China University of Technology; Guangzhou 510640 P. R. China
4. The Hong Kong University of Science and Technology-Shenzhen Research Institute; No. 9 Yuexing 1st RD, Hi-Tech Park Nanshan Shenzhen 518057 P. R. China