Molecular Glue: 1D/3D Heterojunction Suppresses Nonradiative Recombination and C60 Aggregation for Efficient and Stable Perovskite Solar Cells

Constructing 1D/3D heterojunctions at the top interface has emerged as a promising strategy to mitigate non-radiative recombination and improve the stability of perovskite solar cells (PSCs). However, rational molecular design principles of organic components remain elusive, and the morphological instability of fullerene-based electron transport layers has been largely overlooked. Here, we introduce a heterocyclic amidine-functionalized molecule, 1H-pyrazole-1-carboxamidine hydroiodide (PCAI), to construct a 1D/3D heterojunction at the perovskite/C 60 interface. The molecular design features multiple hydrogen-bonding sites, an extended π-conjugated plane, and compact cationic size, enabling selective formation of phase-pure 1D (PCA)PbI 4 perovskitoid, while residual PCA + cations uniformly coat the perovskite surface. This surface reconstruction effectively suppresses non-radiative recombination and optimizes energy-level alignment, yielding a record-level power conversion efficiency of 26.33% among 1D/3D heterojunction-based PSCs. More importantly, PCAI acts as a “molecular glue” that anchors C 60 molecules on the perovskite surface, suppressing C 60 self-aggregation and preserving interfacial integrity under operational stress. This work establishes a clear structure–property–performance relationship for material design and identifies C 60 morphological evolution as a decisive yet previously underexplored stability factor.