Simultaneous Charge Extraction Enhancement and Defect Passivation Via a Planar Conjugated Molecular Interface Enable 22.49%‐Efficient Inorganic Perovskite Solar Cells

Abstract Rational molecular design at the perovskite/hole transport layer (HTL) interface presents a viable strategy to suppress nonradiative recombination in CsPbI 3‐x Br x ‐based perovskite solar cells (PSCs). However, simultaneously achieving efficient defect passivation and rapid charge extraction with a single molecular modifier remains challenging. Herein, we employ a planar conjugated molecule, 1,8‐naphthyridin‐2‐amine (2‐NA), as a multifunctional interfacial modifier that concurrently enhances charge extraction and suppresses interfacial recombination in CsPbI 3‐x Br x PSCs. Combined density functional theory (DFT) calculations and experimental analyses reveal that 2‐NA forms a dense protective layer via noncovalent interactions (e.g., π‐π stacking and hydrogen bonding), effectively passivating undercoordinated Pb 2+ while inhibiting ion migration. Remarkably, 2‐NA incorporation facilitates hot‐carrier extraction, reducing the carrier cooling time from 515 to 240 fs and quadrupling the carrier diffusion length, thereby improving charge transport. As a result, the optimized device achieves a power conversion efficiency (PCE) of 22.49%, the highest reported value for this class of PSCs to date. Furthermore, the device retains 93.6% of its initial PCE after 1008 h under ambient conditions, demonstrating exceptional stability. This work offers a promising molecular engineering approach for enhancing the performance and durability of inorganic PSCs through interfacial modification.