1. College of Chemistry & Materials Science; Northwest University; 1 Xuefu Ave., Guodu Education and Hi-Tech Industries Zone, Chang'an District Xi'an, 710075 Shaanxi Province (P.R. China
2. Institute of Photonics & Photon-Technology; Northwest University; 229 North Taibai Road Xi'an, 710069 Shaanxi Province, (P.R. China