Achieved 18.9% Efficiency by Fine‐Tuning Non‐Fullerene Acceptor Content to Simultaneously Increase the Short‐Circuit Current and Fill Factor of Organic Solar Cells

In this study, using PM6:L8-BO as the main system and non-fullerene acceptor IDIC as the third component, a series of ternary organic solar cells (TOSCs) are fabricated. The results reveal that IDIC plays a significant role in enhancing the performance of TOSCs by optimizing the morphology of blended films and forming interpenetrating nanostructure. The improved film morphology facilitates exciton dissociation and collection in TOSCs, which causes an increase in the short-circuit current density (J_SC ) and fill factor (FF). Further, by optimizing the IDIC content, the power conversion efficiency (PCE) of TOSCs reaches 18.9%. Besides, the prepared TOSCs exhibit a J_SC of 27.51 mA cm^-2 and FF of 76.64%, which are much higher than those of PM6:L8-BO-based organic solar cells (OSCs). Furthermore, the addition of IDIC improves the long-term stability of the OSCs. Meanwhile, TOSCs with a large effective area of 1.00 cm² have been prepared, which exhibit a PCE of 12.4%. These findings suggest that modifying the amount of the third component can be a useful strategy to construct hight-efficiency TOSCs with practical application potential.