Dip Coating of Passivation Layers for FA‐Cs‐Based Perovskite Solar Cells

In the research of perovskite solar cells (PSCs), the introduction of passivation layers is a key strategy for enhancing both efficiency and stability. Employing the well‐established dip‐coating method in conjunction with effective passivation solutions for the preparation of passivation layers not only improves the power conversion efficiency (PCE) and stability of PSCs but also extends the applicability of this approach in the development and commercialization of PSCs. This work introduces a novel passivation method, termed the DATsO‐TBA‐Dip coating (DTD) passivation method, which combines DATsO, 2‐butanol (TBA), and the dip‐coating method. The DTD passivation method was applied to PSCs on glass substrates of different sizes (2 cm × 1.6 cm and 2.5 cm × 2.5 cm). The results demonstrated excellent film quality and significant enhancement in passivation performance. The optimized device achieved a maximum PCE of 22.5% (0.105 cm 2 ), representing a 2.2% improvement over the best‐performing untreated device. Additionally, the open‐circuit voltage ( V OC ) increased to 1.08 V, and the fill factor (FF) improved to 80.9%. Beyond the remarkable photoelectric performance, devices treated with the DTD passivation method also exhibited significantly improved stability, retaining 80% of the initial PCE after 1200 h.