1. State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics Chinese Academy of Sciences 3888 Eastern South Lake Road Changchun 130033 China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
3. Key Laboratory for UV‐Emitting Materials and Technology of Ministry of Education Northeast Normal University Changchun 130024 China