Perspective: Atomic Layer Deposition Strategies for Surface Passivation of Metal-Halide Perovskite Absorbers

Abstract Recent advancements have been made in perovskite solar cells (PSCs) using atomic layer deposition (ALD) of aluminum oxide (Al 2 O 3 ) and other suitable metal oxides such as zirconium oxide (ZrO 2 ) as a perovskite surface passivation technique. ALD has demonstrated significant potential for enhancing photovoltaic (PV) performance and the long-term light, thermal, humidity, and ultraviolet (UV) stability of PSCs by addressing surface defects leading to higher charge extraction and mitigating environmental degradation with only a few nanometers of thickness. However, direct ALD deposition on perovskite films can sometimes degrade the perovskite film from ALD precursor reactivity, elevated temperatures, and vacuum-induced instabilities. This perspective discusses recent strategies, challenges, and future directions for surface passivation of the perovskite solar absorber using ALD to improve device performance and long-term stability for commercialization of PSCs.