1. State Key Laboratory of Structural Chemistry; Fujian Institute of Research on the Structure of Matter, CAS; Fuzhou Fujian 350002 P. R. China
2. Current address: Department of Colloid Chemistry; Max Planck Institute of Colloids and Interfaces; Research Campus Golm 14476 Potsdam Germany
3. MOE Key Laboratory of Cluster Science; Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials; School of Chemistry and Chemical Engineering; Beijing Institute of Technology; Beijing 102488 P.R. China