1. Frontiers Science Center for Flexible Electronics, Xi’an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China
2. Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
3. Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, College of Bioresource Chemical and Materials Engineering, Shaanxi University of Science & Technology, Xi’an 710021, P. R. China
4. Henan Institute of Flexible Electronics (HIFE) and School of Flexible Electronics (SoFE), Henan University, 379 Mingli Road, Zhengzhou 450046, China