1. State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China
2. School of Chemistry and Chemical Engineering, South China University of Technology. Guangzhou 510641, P. R. China
3. Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
4. Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou 510640, P. R. China