14.7% all-small-molecule organic solar cells enabled by fullerene derivative incorporation

The ternary strategy is promising to enhance the photovoltaic properties of organic solar cells (OSCs). Nevertheless, it is full of challenges when this approach involves only small molecules. Herein, a fullerene derivative, ICBA is introduced as the third component to improve the photovoltaic performance of BTR-Cl:Y6-based all-small-molecule (ASM) OSCs. The significant performance enhancement mainly results from reduced bimolecular and trap-assistant recombination, prolonged carrier lifetime and facilitated charge extraction. These findings highlight the effectiveness of the ternary strategy and pave an alternative way for third component selection.