1. Department of Materials ScienceFudan University Shanghai 200433 China
2. Department of Chemical Physics and NanoLundLund University P.O. Box 124 22100 Lund Sweden
3. Department of Physics and State Key Laboratory of Luminescent Materials and DevicesSouth China University of Technology Guangzhou 510640 China
4. Department of ChemistryTechnical University of Denmark DK‐2800 Kongens Lyngby Denmark