1. Department of Materials and Centre for Processable Electronics Molecular Science Research Hub Imperial College London W12 0BZ UK
2. Now at Department of Chemical Engineering National Chung Hsing University 145 Xingda Rd, South Dist. Taichung 402 Taiwan
3. Department of Chemistry and Centre for Processable Electronics Molecular Science Research Hub Imperial College London W12 0BZ UK
4. School of Engineering and Materials Science Queen Mary University of London London E1 4NS UK
5. Department of Physics and Centre for Processable Electronics Imperial College London London SW7 2AZ UK
6. Quality Testing and Inspection Center of Grid Construction Now at China Electric Power Research Institute Beijing 10019 China