1. Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, P.R. China
2. School of Science, Xijing University, Xi’an, P.R. China
3. Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, P.R. China
4. Yantai Xianhua Chemical Technology Company, Yantai, P. R. China
5. Shenzhen Guohua Optoelectronics Tech. Co. Ltd, Shenzhen, P.R. China
6. Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, P.R. China