1. Center
of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, P. R. China
2. 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
3. Key Laboratory of Rubber-Plastics of Ministry of Education/Shandong Province, School of Polymer Science and Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, Qingdao 266042, P. R. China