Mixed-Phase Low-Dimensional Perovskite-Assisted Interfacial Lead Directional Management for Stable Perovskite Solar Cells with Efficiency over 24%

The efficiency and stability of perovskite solar cells are affected by the Pb–I antisite and uncoordinated Pb⁰ defects existing at the interface. Directional management of Pb-based defects can reduce the defect density and voltage loss. In this work, to settle the Pb-based defects at the interface for further stabilization of the perovskite surface, we propose the strategy of designing a low-dimensional perovskite (LDP) by an amphoteric heterocyclic cation which can increase the defect formation energies and inhibit the generation of Pb–I antisite defects. The growth of the mixed-phase LDP can introduce a strong interaction with undercoordinated Pb²⁺ upon the surface of peroskite films accomplished with the ability of dealing with different types of surface-terminating ends. The modified devices showed an increased efficiency of 24.07% (stabilized efficiency of 23.25%) as well as improved overall stability. This opens up a direction for prompting the practical application of perovskite photovoltaic devices based on the directional management of Pb-based interface defects.