1. King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division, Organic Bioelectronics Laboratory, Thuwal 23955-6900, Saudi Arabia
2. KAUST Solar Center, Physical Science and Engineering Division, Materials Science and Engineering Program, KAUST, Thuwal 23955-6900, Saudi Arabia
3. Physics and Astronomy Department, College of Sciences, King Saud University, Riyadh 12372, Saudi Arabia
4. Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
5. Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, People's Republic of China