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 (JSC ) 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 JSC 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.

Solid Additive Enables Organic Solar Cells with Efficiency up to 18.6.

Additive strategies play a critical role in improving the performance of organic solar cells (OSCs). There are only a few reports on the application of solid additives for OSCs, which leaves a large space for further improvement of solid additives and further study on the relationship between material structure and property. PM6:BTP-eC9-based organic solar cells (OSCs) were prepared by using a small molecule BTA3 as a solid additive, and a high energy conversion efficiency of 18.65% is achieved. BTA3 has good compatibility with the acceptor component (BTP-eC9) and optimizes the morphology of the thin films. Moreover, the introduction of a small amount of BTA3 (5 wt %) effectively promotes exciton dissociation and charge transfer and suppresses charge recombination, and the relationship between the BTA3 content and the device parameter is deeply revealed. The use of BTA3 in the active layers is an attractive and effective strategy for high-performance OSCs.