1. Department of ChemistrySauvage Center for Molecular SciencesWuhan University Wuhan 430072 P. R. China
2. State Key Laboratory of Superhard MaterialsCollege of Materials Science and EngineeringJilin University Changchun 130012 P. R. China
3. Institute of Molecular Aggregation ScienceTianjin University Tianjin 300072 P. R. China