1. Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics South China Normal University Guangzhou 510006 P. R. China
2. National Center for International Research on Green Optoelectronics South China Normal University Guangzhou 510006 P. R. China
3. Van't Hoff Laboratory for Physical and Colloid Chemistry Debye Research Institute Utrecht University Padualaan 8 3584 CH Utrecht The Netherlands
4. Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 P. R. China
5. Shandong Energy Institute Qingdao 266101 P. R. China
6. Qingdao New Energy Shandong Laboratory Qingdao 266101 P. R. China
7. Shenzhen Guohua Optoelectronics Tech. Co. Ltd. Shenzhen 518110 P. R. China