Ternary Organic Solar Cells with Binary Additives Finely Regulated Active Layer Morphology and Improved Photovoltaic Performance

Solvent additive can be used to regulate active layer morphology and improve photovoltaic performance of organic solar cells (OSCs). Herein, the PM6:Y6:PC 71 BM ternary bulk heterojunction OSCs are prepared by introducing 1,8‐diiodooctane (DIO) and 1‐chloronaphthalene (CN) as binary additives. On the basis of optimizing the photovoltaic performance with CN additive, the addition of trace amounts of DIO additive further improves the molecular packing of active layer and induces Y6:PC 71 BM acceptor on the surface of active layer. With the optimized active layer morphology, the CN and DIO binary additives restrict carrier recombination and improve charge transport efficiently, and the prepared PM6:Y6:PC 71 BM ternary OSCs with binary additives demonstrate a high short‐circuit current density of 27.15 mA cm −2 and a fill factor of 76.79%, and yield an improved power conversion efficiency of 17.53%, which is higher than that of devices without additives (16.50%) and with DIO (16.79%) or CN additive (17.21%). Binary solvent additives engineering provides an effective strategy to finely regulate active morphology and boost photovoltaic performance of ternary OSCs.