Tailoring Two-Dimensional Ruddlesden–Popper Perovskite via 1D Perovskitoid Enables Efficient and Stable Solar Cells

Two-dimensional (2D) Ruddlesden–Popper (RP) perovskite solar cells (PSCs) have received increasing attention due to their promising optoelectronic properties. Herein, based on low-dimensional engineering, we employ the 1D perovskitoid BZPbI3 (BZ = benzamidine) to tailor the (4F-PEA)2(FA0.3MA0.7)4Pb5I16 perovskite, obtaining the 1D/2D mixed low-dimensional perovskite with favorable phase distribution, orderly crystal orientation, and lower defect density. Furthermore, the 1D BZPbI3 induces a large number of particles to form on the surface, considerably increasing the electrical quality and intrinsic stability of PSCs. Consequently, the 1D/2D PSCs (n = 5) reach a power conversion efficiency (PCE) approaching 20%, accompanied by improved electroluminescent external quantum efficiency. The devices show admirable long-term operational stability, retaining 85% of their initial PCE after continuous illumination at maximum power point (MPP) over 2000 h (50 ± 5 °C). This work illustrates the advantages of 1D perovskitoid in achieving efficient and stable 2D perovskite photovoltaic and other optoelectronic devices.