Third component with a high LUMO energy level enables 17.69% efficiency in ternary organic solar cells

The ternary strategy is thought to be a practical method for improving the power conversion efficiency (PCE) of organic solar cells (OSCs). To create ternary OSCs, a PM6:BTP-BO-4F host blend was combined with the non-fullerene small molecule acceptor BTA3, which has a high lowest unoccupied molecular orbital (LUMO). BTA3 demonstrated complementary absorption spectra and excellent compatibility with BTP-BO-4F, which made it easier to modulate the ternary film's morphology and catch more photons. As a result, the short circuit current density increased. Additionally, BTA3's LUMO level was marginally higher than BTP-BO-4F's, which led to a higher open-circuit voltage of the TOSCs. The addition of BTA3 improved the OSCs' energy transfer and phase separation, which in turn sped up charge transfer and reduced exciton recombination. The PCE of the TOSCs included with 10 wt% BTA3 rose to 17.69% in comparison to a PCE of 16.46% based on host binary OSCs. This research demonstrated that the incorporation of BTA3 with a high LUMO level enabled the fabrication of ternary OSCs with good performance.