Non‐Fullerene Acceptors Assisted Target Therapy for Interface Treatment Enable High Performance Inverted Perovskite Solar Cells

Abstract Targeted treatment of the interface between electron transport layers (ETL) and perovskite layers is highly desirable for achieving passivating effects and suppressing carrier nonradiative recombination, leading to high performance and long‐term stability in perovskite solar cells (PSCs). In this study, a series of non‐fullerene acceptors (NFAs, Y‐H, Y‐F, and Y‐Cl) are introduced to optimize the properties of the perovskite/ETL interface. This optimization involves passivating Pb 2+ defects, releasing stress, and modulating carrier dynamics through interactions with the perovskite. Remarkably, after modifying with NFAs, the absorption range of perovskite films into the near‐infrared region is extended. As expected, Y‐F, with the largest electrostatic potential, facilitates the strongest interaction between the perovskite and its functional groups. Consequently, champion power conversion efficiencies of 21.17%, 22.21%, 23.25%, and 22.31% are achieved for control, Y‐H‐, Y‐F‐, and Y‐Cl‐based FA 0.88 Cs 0.12 PbI 2.64 Br 0.36 (FACs) devices, respectively. This treatment also enhances the heat stability and air stability of the corresponding devices. Additionally, these modifier layers are applied to enhance the efficiency of Cs 0.05 (FA 0.95 MA 0.05 ) 0.95 PbI 2.64 Br 0.36 (FAMA) devices. Notably, a champion PCE exceeding 24% is achieved in the Y‐F‐based FAMA device. Therefore, this study provides a facile and effective approach to target the interface, thereby improving the efficiency and stability of PSCs.