Orientation Engineering via 2D Seeding for Stable 24.83% Efficiency Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have been extensively researched as a promising photovoltaic technology, wherein the orientation of the perovskite film plays a crucial role in the power conversion efficiency (PCE) and stability. Here, a seed-mediated method is developed to in situ grow a layer of 2D perovskite seed for epitaxial growth of 3D perovskite atop it to construct a high-quality 2D/3D heterojunction. It is found that the epitaxial 3D perovskite film exhibits a preferred [112] direction, which is different from traditional perovskites with a preferred [001] orientation. The oriented perovskite film consists of large-sized grains with low defect density, long charge-carrier lifetime, and good stability, resulting in efficient PSCs with a champion efficiency of 24.83%. In addition, the devices exhibit high stability under ambient, thermal, and continuous light-soaking conditions. This work provides an effective strategy for achieving high-quality perovskite films with tunable orientation to simultaneously boost the efficiency and stability of PSCs.