1. Key Laboratory of Luminescence and Optical Information; Ministry of Education; Beijing Jiaotong University; Beijing 100044 China
2. Division of Nanophotonics; CAS Key Laboratory of Standardization and Measurement for Nanotechnology; CAS Center for Excellence in Nanoscience; National Center for Nanoscience and Technology; Beijing 100044 China
3. Department of Material Science and Technology; Guangxi Key Laboratory of Information Materials; Guilin University of Electronic Technology; 1 Jinji Road Guilin 541004 China
4. Key Laboratory of Soft Chemistry and Functional Materials; Ministry of Education; Nanjing University of Science and Technology; Nanjing 210094 China