Low-Dimensional Ligand-Driven Design of 2D/3D Perovskite Heterojunctions: Achieving Mitigated Nonradiative Recombination and Robust Stability for Next-Generation Solar Cells

Achieving efficient and stable perovskite solar cells (PSCs) is challenging due to nonradiative recombination, ion migration, and film instability. This study designs low-dimensional (LD) ligands─benzimidazole (BIZ), 1H-benzimidazole, 6-methyl-, (6-MeBIm), and 1H-benzimidazole, 6-(trifluoromethyl)-, (6-TFBIm)─to construct LD/3D perovskite heterojunctions. Compared with BIZ and 6-MeBIm (constructing 1D/3D perovskite heterojunction), the 2D/3D perovskite heterojunction constructed by 6-TFBIm successfully passivated different defects, resulting in a significant reduction in nonradiative recombination and improved carrier transport, leading to a power conversion efficiency (PCE) of 25.25%, outperforming the control devices (PCE: 22.97%). The 2D/3D PSCs exhibit superior humidity and thermal stability, maintaining structural integrity under harsh conditions. These results underscore the role of tailored LD ligands in optimizing perovskite film quality, charge transport, and stability, paving the way for high-performance and durable PSCs.