Processing Friendly Slot-die Cast Non-Fullerene Organic Solar Cells with Optimized Morphology

The power conversion efficiencies (PCEs) of spin-coated organic solar cells (OSCs) have increased rapidly in recent years. However, spin-coating shows poor reproducibility for large-scale production. Slot-die coating, a lab-scale version of roll-to-roll fabrication, has been considered as the most suitable technique for the production of future large-area commercial devices. For this, highly efficient slot-die fabricated devices are required to approach the performance of spin cast OSCs. We present here, a non-fullerene OSC device utilizing PBDB-T:i-IEICO-4F blend, fabricated by slot-die coating without post treatment in the ambient conditions. Device showed an impressive PCE of 12.5%, which is one of the highest reported performance for slot-die coated OSC devices. Compared to spin-coated and blade-coated films with optimized thermal annealing time, the films fabricated by slot-die coating (without any treatment) exhibit not only the highest degree of crystallinity and face-on orientation, but also the s...