Interfacial Locking Strategy by Porous Low‐Dimensional Structure for High‐Efficiency and Stable Inverted Perovskite Solar Cells

ABSTRACT In p‐i‐n inverted perovskite solar cells, the photochemical instability and interfacial diffusion of small‐molecule electron transport layers (e.g., PCBM) are critical bottlenecks limiting long‐term operational stability. Herein, we introduce a bis‐pyridine bidentate ligand to reconstruct the three‐dimensional perovskite surface into a discontinuous, porous low‐dimensional phase. Unlike conventional continuous capping layers that impede charge transport, this unique porous architecture achieves simultaneous protection and extraction. The chemically robust low‐dimensional framework, anchored via bidentate coordination, encapsulates the intrinsically fragile perovskite surface and provides steric hindrance against small‐molecule diffusion. Meanwhile, its discontinuous porosity enables PCBM to penetrate and form an interpenetrating network with the underlying perovskite, dramatically expanding the effective interfacial contact area for carrier extraction without introducing transport resistance. This “porous interfacial locking” strategy fundamentally resolves the passivation‐extraction dilemma inherent in traditional interface engineering. Consequently, champion devices achieve a power conversion efficiency of 27.06% with enhanced open‐circuit voltage and fill factor, while unencapsulated devices retain over 95% of their initial efficiency after 1200 h of continuous maximum power point tracking. This work establishes discontinuous porous locking as a viable design principle for achieving simultaneous high efficiency and stability in perovskite optoelectronics.