Interfacial Multidentate Chelation Enabled Anti‐Aggregation Self‐Assembled Monolayers for High‐Performance Inverted Perovskite Solar Cells

Abstract

ABSTRACT The quality of self‐assembled monolayers (SAMs) and the defect density at the perovskite buried interface are key factors determining the performance of inverted perovskite solar cells (IPSCs). However, the inherent aggregation of SAM molecules at this interface limits further efficiency improvements. Herein, we develop an interfacial multidentate chelation (IMC) strategy that integrates anti‐aggregation functionality into SAMs for buried interface regulation. Specifically, 2,2′:6′,2′′‐terpyridine (TERPY) is introduced into the SAM of [4‐(3,6‐dimethoxy‐9H‐carbazol‐9‐yl)butyl]phosphonic acid (MeO‐4PACz). The π‐π interactions between MeO‐4PACz and TERPY suppress SAM self‐aggregation, resulting in a compact and uniform SAM layer. Meanwhile, the three pyridinic nitrogen atoms in TERPY chelate with undercoordinated Pb 2 + defects through multidentate Pb‐N coordination, reducing interfacial defect states. Benefiting from these dual effects, the champion power conversion efficiencies (PCEs) of small‐area (0.043 cm 2 ) and large‐area (1 cm 2 ) IPSCs reach 26.23% and 25.43%, respectively. Encapsulated devices retain 82.75% of their initial PCE after 1300 h of maximum power point tracking (MPPT) under the ISOS‐L‐2 protocol. This work provides a feasible strategy for simultaneously regulating SAM assembly and passivating buried interface defects.