1. Key Laboratory of Luminescence and Optical Information Ministry of Education Beijing Jiaotong University Beijing 100044 P. R. China
2. State Key Laboratory of Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 P. R. China
3. Key Lab for Special Functional Materials Ministry of Education National and Local Joint Engineering Research Center for High‐Efficiency Display and Lighting Technology and School of Materials Henan University Kaifeng 475004 P. R. China
4. BOE Technology Group Co., LTD No. 9 Dize Road Beijing 100176 P. R. China