1 Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, 999077, P. R. China.
2 Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, 999077, P. R. China.
3 Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, P. R. China.
4 Joint School of National University of Singapore and Tianjin University, Fuzhou International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, P. R. China.
5 Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
6 Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany.
7 Department of Chemistry, University of Cologne, Greinstr. 4-6, Cologne, 50939, Germany.