1. Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Chengfu Road 292, Haidian district Beijing 100871 R. P. China
2. Chemistry and Chemical Engineering Guangdong Laboratory Shantou 515031 P. R. China
3. Spin-X Institute, School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510641 P. R. China
4. Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials Guangzhou 510641 P. R. China