Tailored Molecular Dipole Enables Strengthened Passivation Toward Efficient and Stable P‐I‐N Perovskite Solar Cells

Abstract Interfacial engineering employing inorganic halide salts or organic molecules has been widely reported as an effective approach to extenuate the non‐radiative recombination loss at interfaces of perovskite solar cells (PSCs). Here, the strengthened contact passivation is demonstrated at the perovskite/electron transport layer (ETL) interface using dipole molecules (DMs) with tailored functional groups. Through combined experimental and theoretical characterizations, it is revealed that electric dipoles can form at the cathodic contact interfaces, and their orientation and strength are governed by the functional groups of DMs. In comparison with control and carboxyl (−COOH) group based DMs, the trifluoromethyl (−CF 3 ) group substitution enables more favorable energy level alignment, which further provides a larger energetic driving force for charge separation and extraction. Finally, the −CF 3 ‐based DM‐engineered P‐I‐N structured PSCs output a best power conversion efficiency of 25.83%, which is significantly improved relative to the pristine (23.34%), control device (24.02%), and –COOH DM based ones (24.88%). Additionally, the hydrophobic nature of −CF 3 and strengthened contact passivation enables enhanced storage and operational stability. These findings highlight the significance of interfacial dipole molecular structure in enhancing contact passivation and regulating carrier dynamics for efficient and stable P‐I‐N PSCs.