Acid-Base Complexation Induced Dipole Engineering for Durable Inverted Perovskite Photovoltaics.

Abstract

Thermally unstable buried interfaces hinder the commercialization of inverted perovskite solar cells (PSCs). Although self-assembled monolayers (SAMs) serve as promising hole-selective contacts, their inadequate coverage and weak thermal anchoring cause energy loss and structural degradation. Here, we introduce a dipole-engineering strategy by incorporating 4-aminopyridine (4-AP) into the Me-4PACz matrix to form a robust electrostatic complex via acid-base complexation. This approach suppresses aggregation, ensures uniform coverage, enables a vertical molecular orientation, and enhances the interfacial dipole moment from 1.64 to 8.34 Debye, thereby improving hole extraction. The resulting small-area (0.09 cm²) inverted PSC achieves a power conversion efficiency (PCE) of 27.06% and an open-circuit voltage (V_OC) of 1.194 V. This approach also enables large-area modules (655.2 cm²) with an efficiency of 20.3% (certified 20.11%) and a fill factor of 79.9%. Additionally, the devices demonstrate exceptional thermal stability, retaining 90.1% and 89.3% of their initial PCE after 1000 h at 85°C and 200 thermal cycles, respectively. This work provides a generalizable pathway toward durable and high-performance perovskite photovoltaics by leveraging supramolecular interactions for interfacial dipole engineering.