1. Beijing Key Laboratory for Optical Materials and Photonic Devices Department of Chemistry Capital Normal University Beijing 100048 P. R. China
2. School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
3. Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link 637371 Singapore Singapore
4. National Engineering Research Center for Bioengineering Drugs and the Technologies Institute of Translational Medicine, Nanchang University Nanchang Jiangxi 330038 P. R. China