1. Shenzhen Key Laboratory of New Information Display and Storage Materials College of Materials Science and Engineering Shenzhen University Shenzhen 518060 P. R. China
2. School of Chemical Sciences University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Hubei Key Lab on Organic and Polymeric Optoelectronic Materials Department of Chemistry Wuhan University Wuhan 430072 P. R. China