Stable, Efficient, and Scalable Two-Dimensional Perovskites for Next-Generation Solar Cells.

Metal halide perovskites have rapidly evolved from a niche class of semiconductors to a leading platform for advanced photovoltaic technologies. Within this family of materials, two-dimensional (2D) perovskites have emerged as structurally engineered derivatives that offer enhanced environmental stability relative to their three-dimensional counterparts. However, reduced dimensionality also introduces a distinct optoelectronic regime governed by confinement effects and structural anisotropy, which complicates the direct translation of established design strategies. This review presents a unified perspective on the design and optimization strategies of 2D perovskite solar cells, including how spacer chemistry, inorganic slab thickness, and crystallization kinetics jointly influence transport anisotropy, film formation, and optical properties with implications for stability and device performance. Finally, the scalable integration pathways, including blade coating, printing techniques, machine learning-guided fabrication, and vapor deposition techniques for 2D perovskite materials for solar cell fabrication, are considered.