1. Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University 1 , Lanzhou 730070, China
2. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences 2 , Lanzhou 730000, China
3. Institute of Optoelectronic Materials and Devices, Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology 3 , Ganzhou 341000, China
4. State Key Laboratory for Organic Electronics and Information School of Chemistry and Life Sciences, Nanjing University of Posts and Telecommunications 4 , Nanjing 210023, China