1. Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
2. Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
3. Institute of Materials Science of Barcelona (ICMAB-CISC), Campus de la UAB, 08193, Bellaterra, Spain
4. KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
5. Department of Chemistry, Imperial College London, London SW7 2AZ, U.K.