1. King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
2. Department of Chemistry and Centre for Processable Electronics, White City Campus, Imperial College London, London W12 0BZ, U.K.
3. King Abdullah University of Science and Technology (KAUST), Core Laboratories, Thuwal 23955, Saudi Arabia
4. King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division (PSE), Thuwal 23955, Saudi Arabia
5. Department of Physics, National Technical University of Athens, Athens GR-15780, Greece