1. Key Laboratory of Luminescence and Optical Information Ministry of Education, Beijing Jiaotong University Beijing 100044 China
2. BOE Technology Group Co. LTD No. 9 Dize Road Beijing 100176 China
3. School of Optoelectronics Beijing Institute of Technology Beijing 100081 China
4. Organic Optoelectronic Materials Laboratory Department of Chemistry College of Science Korea University Seoul 02841 Republic of Korea
5. State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 China