1. Speciality Fibers and Nuclear Materials Engineering Laboratory, Ningbo Institute of Materials Technology and Engineering, Ningbo Institute of Industrial Technology, Chinese Academy of Sciences, Ningbo 315201, China
2. Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
3. Department of Physics, Faculty of Science, Ningbo University, Ningbo 315201, China
4. Departments of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States