Protective Coating Interfaces for Perovskite Solar Cell Materials: A First-Principles Study

Funding Information: We acknowledge the computing resources from the CSC-IT Center for Science, the Aalto Science-IT project, and Xi’an Jiaotong University’s HPC Platform. We further acknowledge funding from the Väisälä Foundation and the Academy of Finland through its Key Project Funding scheme (305632) and postdoctoral grant no. 316347. Finally, we acknowledge the AIMSS grants (316601) for their support. The data that support the findings of this study will be openly available in the Novel Materials Discovery (NOMAD) repository. Publisher Copyright: © 2022 The Authors. Published by American Chemical Society.The protection of halide perovskites is important for the performance and stability of emergent perovskite-based optoelectronic technologies. In this work, we investigate the potential inorganic protective coating materials ZnO, SrZrO3, and ZrO2 for the CsPbI3 perovskite. The optimal interface registries are identified with Bayesian optimization. We then use semilocal density functional theory (DFT) to determine the atomic structure at the interfaces of each coating material with the clean CsI-terminated surface and three reconstructed surface models with added PbI2 and CsI complexes. For the final structures, we explore the level alignment at the interface with hybrid DFT calculations. Our analysis of the level alignment at the coating-substrate interfaces reveals no detrimental mid-gap states but rather substrate-dependent valence and conduction band offsets. While ZnO and SrZrO3 act as insulators on CsPbI3, ZrO2 might be suitable as an electron transport layer with the right interface engineering.Peer reviewe