1. College of Physics, Qingdao University, Qingdao 266071, China
2. College of Microtechnology & Nanotechnology, Qingdao University, Qingdao 266071, China
3. School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710000, China
4. State Key Laboratory of Bio Fibers and Eco Textiles, Qingdao University, Qingdao 266071, China