1. School of Chemistry and Chemical EngineeringBeijing Institute of Technology Beijing 100081 P. R. China
2. School of Material Science and Chemical EngineeringNingbo University Ningbo 315211 P. R. China
3. State Key Laboratory of Luminescent Materials and Devices Institute of Polymer Optoelectronic Materials and DevicesSouth China University of Technology Guangzhou 510640 P. R. China
4. PetroChina Research Institute of Petroleum Exploration & Development Beijing 100083 P. R. China