Influences of deposition conditions on atomic layer deposition films for enhanced performance in perovskite solar cells

Atomic layer deposition (ALD) is a key technology for fabricating functional layers in perovskite solar cells, as it can deposit pinhole-free films with atomic-level thickness and tunable composition on high-aspect-ratio surfaces. Various deposition conditions have significant effects on the growth, physical, and chemical properties of ALD films, which, in turn, critically influences the performance of associated devices. Here, we review the reaction mechanisms underlying ALD and summarize how variables, such as precursors, deposition temperatures, and substrates, impinge upon the quality of ALD films and the related devices. We emphasize the role of substrate in determining the nucleation and growth behavior of ALD films, which has been overlooked in previous reviews. Finally, we highlight the potential application of ALD in efficient perovskite solar cells in terms of carrier transport, encapsulated, and buffer layers, especially for tandem cells.