1. Department of Materials Science and Engineering
2. College of Engineering
3. Peking University
4. Beijing 100871
5. People's republic of China
6. Department of Materials Physics and Chemistry
7. School of Materials Science and Engineering
8. University of Science and Technology Beijing
9. Beijing 100083
10. Key Laboratory of Organic Polymer Photoelectric Materials
11. School of Science
12. Xijing University
13. Xi'an