1. Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
2. Department of Materials Science and Engineering, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
3. Department of Chemistry and Centre for Processable Electronics, Imperial College London, London, United Kingdom
4. Georg-August-Universität Göttingen, I. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
5. School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
6. KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Materials Science and Engineering Program (MSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
7. Department of Chemistry, University of Oxford, Oxford, United Kingdom