1. School of Physics and Electronics
2. Hunan University
3. Changsha 410082
4. P. R. China
5. Key Laboratory of Molecular Nanostructure and Nanotechnology
6. Beijing National Laboratory for Molecular Sciences
7. Institute of Chemistry
8. Chinese Academy of Sciences(CAS)
9. Beijing 100190
10. Materials Science and Engineering Program
11. Texas Materials Institute
12. The University of Texas at Austin
13. Austin
14. USA