1. Beijing National Laboratory for Molecular Science; Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences; Beijing 100190 P. R. China
2. Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety; Institute of High Energy Physics, Chinese Academy of Sciences; Beijing 100049 P. R. China
3. College of Chemistry; Sichuan University; Chengdu 610064 P. R. China
4. Beijing National Laboratory for Condensed Matter Physics; Institute of Physics, Chinese Academy of Sciences; Beijing 100190 P. R. China
5. State Key Laboratory of Material Processing and Die & Mould Technology, School of Material Sciences and Engineering, Huazhong University of Science and Technology; Wuhan 430074 P. R. China