Employing a similar acceptor material as the third component to enhance the performance of organic solar cells†

We synthesized two derivatives of Y6, namely Y-TNF and Y-TN. Compared to Y6, these two derivatives possess fluorinated and non-fluorinated extended terminal groups, respectively. Y-TNF exhibits a red-shifted absorption compared to Y-TN, a narrower bandgap, and a better matched energy level to the donor material PM6. Hence, Y-TNF demonstrates better photovoltaic performance. The incorporation of Y-TN further enhances the photovoltaic performance of binary PM6:Y-TNF devices due to its good compatibility and intermolecular interactions with Y-TNF, resulting in improved charge transport and reduced non-radiative energy loss. The ternary organic solar cells (OSCs) offer a higher device efficiency of 16.63% with a high open-circuit voltage of 0.857 V, a high short-circuit current density of 25.84 mA cm⁻², and a high fill factor of 75.10%. The results show that incorporating a similar acceptor material as the third component is an effective strategy to enhance the performance of OSCs.