1. Humboldt Centre for Nano‐ and Biophotonics Department of Chemistry University of Cologne Greinstr. 4–6 50939 Köln Germany
2. Physical Science and Engineering Division King Abdullah University of Science and Technology (KAUST) Thuwal 23955–6900 Saudi Arabia
3. Organic Semiconductor Centre SUPA School of Physics and Astronomy University of St Andrews St Andrews KY16 9SS UK