1. College of Physics and Electronic Information, Yunnan Normal University, Kunming, Yunnan650500, China
2. Yunnan Key Laboratory of Opto-electronic Information Technology, Yunnan Normal University, Kunming, Yunnan650500, China
3. Key Laboratory of Advanced Technique & Preparation for Renewable Energy Materials, Ministry of Education, Yunnan Normal University, Kunming, Yunnan650500, China