1. Beijing Key Laboratory for Optical Materials and Photonic DevicesDepartment of ChemistryBeijing Advanced Innovation Center for Imaging TechnologyCapital Normal University Beijing 100048 P. R. China
2. Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistryTianjin University and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 P. R. China
3. Beijing National Laboratory for Molecular SciencesInstitute of chemistry, Chinese Academy of Sciences Beijing 100190 P. R. China