1. School of Science, Tianjin University of Technology, Tianjin 300384, China
2. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
3. School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
4. International Iberian Nanotechnology Laboratory (INL), Ave. Mestre Jose Veiga, 4715-330 Braga, Portugal
5. School of Materials Science and Engineering, Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, and Tianjin Key Laboratory for Photoelectric Materials and Devices, and National Demonstration Center for Experimental Function Materials Education, Tianjin University of Technology, Tianjin 300384, China