Development of tin halide perovskites is limited by the extremely poor stability and high background carrier density. Here, based on a pseudohalogen ''catalyst,'' we fabricated a Sn-based hierarchy structure perovskite in a one-step process, comprising highly parallel-orientation 2D PEA 2 SnI 4 on the surface of 3D FASnI 3 . The hierarchy structure delivers significantly enhanced stability and oxidation resistance in air atmosphere. We then explored hierarchy structure perovskite films in planar structure solar cells and achieved a PCE up to 9.41%. HIGHLIGHTS 2D-quasi-2D-3D hierarchy structure perovskite is fabricated for the first time Removable pseudohalogen acts as a regulator to manipulate tin perovskite structureThe hierarchy structure effectively resists oxidation and increases carrier mobilityThe hierarchy structure tin perovskite solar cells achieve a record PCE of 9.41% Wang et al., Joule SUMMARYThe power conversion efficiency (PCE) of tin perovskite solar cells is impeded by the extremely poor resistance to oxidation and high density of intrinsic Sn vacancies. Herein, we grow a 2D-quasi-2D-3D Sn perovskite film using removable pseudohalogen NH 4 SCN as a structure regulator. This hierarchy structure remarkably enhances air stability resulting from the parallel growth of 2D PEA 2 SnI 4 as the surface layer. We then explore the hierarchy structure perovskite films in planar structural solar cells, which generate a PCE up to 9.41%. The device retains 90% of its initial performance for almost 600 hr. Our results suggest that adding removable NH 4 SCN in a perovskite precursor can significantly improve the stability and photovoltaic performance of Sn perovskite. This finding provides a powerful strategy to manipulate the structure of low-dimensional perovskite in order to enhance the performance of perovskite solar cells.

E. H. (2022). Quantum-size-tuned heterostructures enable efficient and stable inverted perovskite solar cells. Nature Photonics.