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