1. School of Energy and Machinery Engineering, Jiangxi University of Science and Technology, Nanchang 330006, P. R. China
2. Key Laboratory of Rare Earth Luminescence Materials and Devices of Jiangxi Province, Ganzhou 341000, P. R. China
3. School of Materials Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, P. R. China