1. National
Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, P. R. China
2. Center for Crystal Research and Development
and Laboratory of Photochemical Conversion and Optoelectronic Materials,
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
3. Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States