Mixed perovskites (2D/3D)-based solar cells: a review on crystallization and surface modification for enhanced efficiency and stability

Solar cells based on a three-dimensional (3D) crystalline perovskite framework exhibit desired photoconversion efficiency. However, 3D perovskites are prone to surface defects, leading to severe Shockley-Read-Hall (SRH) recombination and insufficient interactions between components, resulting in lower efficiency and stability. In contrast, two-dimensional (2D) perovskites have comparatively better excellent stability in hot and humid environments but suffer from lower efficiency. Recently, researchers reported that surface passivation of 3D perovskite by 2D perovskite improves the stability of solar cells without compromising their efficiency. In this review, the recent advances in surface modification of three-dimensional perovskites using two-dimensional perovskites are discussed. The crystal structures, photoelectric properties, and surface passivation strategies of 2D/3D perovskite solar cells with different components are systematically presented. Finally, the prospect of using two-dimensional perovskite passivation technology to further improve photovoltaic performance is discussed.