1. Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China
2. School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
3. Department of Applied Physics, Chongqing University, Chongqing 400044, China
4. School of Materials Science & Engineering, Beijing Institute of Fashion Technology, Beijing 100029, China
5. Beijing Key Laboratory of Clothing Materials R&D and Assessment, Beijing 100029, China
6. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245, United States