1. Key Laboratory of Luminescence and Optical Information Ministry of Education Department of Physics School of Science Beijing Jiaotong University Beijing 100044 China
2. Chemistry and Chemical Engineering Guangdong Laboratory Shantou 515031 China
3. Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China
4. Department of Mechanical Engineering and Centre of nanofibers and nanotechnology (NUSCNN) National University of Singapore 117576 Singapore Singapore
5. Science and Engineering Faculty Queensland University of Technology (QUT) 2 George St. Brisbane QLD 4000 Australia