1. College of Electronic and Optical Engineering and College of Microelectronics Institute of Flexible Electronics (Future Technology) Nanjing University of Posts and Telecommunications (NJUPT) 9 Wenyuan Road Nanjing Jiangsu 210023 P. R. China
2. Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials (IAM) Nanjing University of Posts and Telecommunications (NJUPT) 9 Wenyuan Road Nanjing Jiangsu 210023 P. R. China
3. Department of Chemistry Hong Kong Baptist University Waterloo Road Hong Kong P. R. China
4. Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University (PolyU) Hung Hom Hong Kong P. R. China
5. PolyU Shenzhen Research Institute Shenzhen 518057 P. R. China