1. Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province
2. Taiyuan University of Technology
3. Taiyuan 030024
4. China
5. Department of Chemistry
6. Brown University
7. Providence
8. USA
9. Nanocluster Laboratory
10. Institute of Molecular Science
11. Shanxi University
12. Taiyuan 030006
13. Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education
14. Tsinghua University
15. Beijing 100084