1. School of Chemical Engineering and Materials, Heilongjiang University, Harbin 150080, P. R. China
2. School of Electronic Engineering, Heilongjiang University, Harbin 150080, P. R. China
3. Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China
4. South China Advanced Institute for Soft Matter Science and Technology, South China University of Technology, Guangzhou 510640, P. R. China