A ternary cascade structure enhances the efficiency of polymer solar cells

In this study, a novel solution-processed small molecule (TQTFA) for use as an electron donor has been incorporated into organic solar cells based on poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C71-butyric acid methyl (PC[70]BM). The combination of TQTFA with P3HT and PC[70]BM allows not only a broad absorption but also tuning of the inter energy level leading to a higher short-circuit current (J(SC)) and open-circuit voltage (V-OC). The best performing devices exhibited a power conversion efficiency of 4.50%. The efficiency is increased by almost 15% when compared to the one without TQTFA.