Abstract 

formamidinium lead triiodide (FAPbI₃) absorber are often hindered by defects at the surface and grain boundaries of the perovskite. To address this, we demonstrate the use of pyrrolidinium iodide for the in-situ formation of an energetically aligned one-dimensional (1D) pyrrolidinium lead triiodide (PyPbI₃) capping layer over the 3D FAbI₃ perovskite. The thermodynamically stable PyPbI₃ perovskitoids, formed through cation exchange reactions, effectively reduces surface and grain boundary defects in the FAPbI₃ perovskite. In addition to improved phase stability, the resulting 1D/3D perovskite film forms a cascade energy band alignment with the other functional layers in PSCs, enabling a barrier-free interfacial charge transport. With a maximum power conversion efficiency (PCE) of ~23.1% and ~20.7% at active areas of 0.09 and 1.05 cm², respectively, the 1D/3D PSCs demonstrate excellent performance and scalability. Leveraging this improved scalability, we have successfully developed a mechanically-scribed 1D/3D perovskite mini-module with an unprecedentedly high PCE of ~20.6% and a total power output of ~270 mW at an active area of ~13.0 cm². The 1D/3D multi-dimensional perovskite film developed herein holds great promise for producing low-cost, high-performance perovskite photovoltaics at both the cell and module levels.