Unraveling the Reasons Behind SnO2/Perovskite Defects and Their Cure Through Multifunctional Ti3C2TX

Abstract The rationale for low performances in perovskite solar cells with buried interface still needs to be clarified, owing to the complicated physiochemistry of metal oxides/perovskite interface, and literature offers a meager knowledge about the reactions at this interface. While exploring the SnO 2 /perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI 2 residue and metallic Pb 0 are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti 3 C 2 T X at the SnO 2 /perovskite interface detaches the SnO 2 hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti 3 C 2 T X passivates the interface defects via its functional groups and establishes ballistic pathways for electrons with high chances of non‐radiative recombination. Thus, 25.19% (certified as 24.41%) of efficiency with superior long‐term operational stability is achieved.