Unraveling the Reasons Behind SnO₂/Perovskite Defects and Their Cure Through Multifunctional Ti₃C₂T_X

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 SnO₂/perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI₂ residue and metallic Pb⁰ are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti₃C₂T_X at the SnO₂/perovskite interface detaches the SnO₂ hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti₃C₂T_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.