1. National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650091, P.R. China
2. Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan University, Kunming 650091, P.R. China
3. School of Chemical Sciences & Technology, Yunnan University, Kunming 650091, P.R. China