1. School of Science, China University of Geosciences (Beijing), Beijing 100083, P.R. China
2. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China
4. School of Chemistry, South China Normal University, Guangzhou 510006, P.R. China
5. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States