1. School of Chemistry and Chemical Engineering; Shanxi University; 030006 Taiyuan P. R. China
2. College of Materials Science and Optoelectronic Technology; University of Chinese Academy of Sciences; 101408 Yanqi Lake Huairou District, Beijing P. R. China
3. Scientific Instrument Center; Shanxi University; Taiyuan
4. Ordos Institute of Technology; 017000 Ordos Inner Mongolia P. R. China