Multidentate Molecular Anchoring for Enhanced Interfacial Stability and Reliable Perovskite Solar Cells

ABSTRACT High‐performance inverted perovskite solar cells (PSCs) rely critically on high‐quality interfaces and efficient bulk defect passivation. However, achieving simultaneous optimization of charge extraction and lattice stabilization through functional molecular modifiers remains a persistent challenge in the field. Herein, we demonstrate a multidentate molecular anchoring strategy leveraging tripodal phosphonic acid molecules to regulate the co‐deposition dynamics of the perovskite absorber and hole transport layer. The trifurcated phosphonic acid moieties enable robust multidentate chemisorption onto the glass substrate, yielding an interface with face‐on π‐stacking orientation that facilitates optimal band alignment and suppresses interfacial charge recombination. Concurrently, these molecules segregate preferentially to perovskite grain boundaries, where they engage in coordinative passivation of undercoordinated Pb 2 + defects. This dual‐functional design constructs a coherent charge‐transport network that synergistically enhances interfacial hole extraction while mitigating ion migration and bulk defect formation. The resulting PSCs deliver a certified power conversion efficiency of 26.35%, accompanied by exceptional operational stability: retaining 82% of their initial performance after 1000 h of thermal stability test (85°C) and 86% after 1000 h of maximum power point tracking. This work establishes critical insights into molecular‐mediated interface stabilization, providing a generalized framework for the rational design of functional molecules for optoelectronic devices.