1. State Key Laboratory of Silicon MaterialsMOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang University Hangzhou 310027 P. R. China
2. Department of ChemistryZhejiang University Hangzhou 310027 P. R. China
3. State Key Laboratory of Luminescent Materials and DevicesSchool of Materials Science and EngineeringSouth China University of Technology Guangzhou 510640 P. R. China
4. Department of PhysicsChinese University of Hong Kong New Territories Hong Kong P. R. China