Building Scalable Buried Interface for High‐Performance Perovskite Photovoltaic Devices

Abstract The quality of the buried interface plays a key role in achieving high‐performance perovskite solar cells (PSCs). However, it is challenging to guarantee its quality on a larger area, which is pivotal for the commercialization of PSCs. Here, a facile strategy is developed to modify the SnO₂/perovskite buried interface by incorporating L‐Aspartic acid monosodium salt (ASP‐Na) into SnO₂ colloidal dispersion. ASP‐Na with multidentate ligands can coordinate with Sn to form stable dispersion, inhibiting the agglomeration of nanoparticles at the buried interface. In addition, the coordination between ASP‐Na and SnO₂ nanoparticles in turn promotes the uniform distribution of ASP‐Na, which facilitates the uniform and effective passivation of the buried defects. Consequently, the ASP‐Na treatment improves the device efficiency from 23.44% to 25.47% (certified 25.02%) with an aperture area of 0.0797 cm² without hysteresis and enhances the operation stability. The perovskite mini‐module achieves an efficiency of 20.11% with an aperture area of 18.30 cm², demonstrating the potential of the strategy for scalability.