1. State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi’an, P. R. China
2. Optical and Electrical Material Center, Xi’an Modern Chemistry Research Institute, Xi’an, P. R. China
3. State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, P. R. China
4. School of Materials Science and Engineering, Shaanxi Normal University, Xi’an, P. R. China