1. Zhongshan Branch of State Key Laboratory of Electronic Thin Films and Integrated Devices, Zhongshan Institute, University of Electronic Science and Technology of China; Zhongshan 528402 P.R. China
2. School of Materials Science and Engineering, Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology; Guilin 541004 P.R. China
3. Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University; Shanghai 200072 P.R. China