1. Key Laboratory for Organic Electronics & Information Displays and Institute of Advanced Materials
2. Nanjing University of Posts & Telecommunications
3. Nanjing 210046
4. P. R. China
5. Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education
6. Nanjing University of Science and Technology
7. Nanjing 210094
8. Jiangsu-Singapore Joint Research Center for Organic/Bio-Electronics & Information Displays and Institute of Advanced Materials