Grain Boundary and Buried Interface Suturing Enabled by Fullerene Derivatives for High-Performance Perovskite Solar Module

For fabricating high-performance perovskite solar cells (PSCs) and modules, it is crucial to obtain high-quality perovskite (PVSK) films and efficient interfacial charge transport. Here, we introduce a synergistic strategy combining a [6,6]-4-fluorophenyl-C61-butyric acid (FPAC60) self-assembled monolayer (SAM) and a bis-adduct 2,5-(dimethyl ester) C60 fulleropyrrolidine (bis-DMEC60) additive to obtain an efficient device. The FPAC60 SAM can not only promote charge transport and passivate defects at the SnO2/PVSK buried interface but also serve as a nucleation site to regulate the crystallization process of PVSK films. Meanwhile, the bis-DMEC60 located at the grain boundaries (GBs) can effectively suppress carrier recombination and ion migration. Combining the interfacial and GB suture functions of FPAC60 and bis-DMEC60, the large-area (1 cm2) cell delivers a champion power conversion efficiency of 22.58%, and the 6 × 6 cm2 mini-module demonstrates an efficiency of 19.53% (certified 18.8%). The as-fabricated modules also exhibit promising illumination and thermal stability, retaining over 90% of their initial efficiencies after 1000 h.