Water Stable Haloplumbate Modulation for Efficient and Stable Hybrid Perovskite Photovoltaics

Abstract The commercialization of perovskite solar cells is mainly limited by their operational stability. Interlayer modification by thin interface materials between the perovskite and the charge transport layers is one of the most effective methods to promote the efficiency and stability of perovskite devices. However, the commonly used interlayer materials do not fulfill all the demands, including good film quality, excellent stability, and passivation capability without interfering with the charge transport. In this work, a water stable haloplumbate [TBA]PbI 3 for interfacial modification that meets these demands is proposed, which is formed on the perovskite surface in situ by tetra ‐butylammonium iodide treatment. Benefiting from its passivation effect and robustness, the modified devices result in a power conversion efficiency of 22.90% with enhanced environmental and operational stability. In addition, the self‐limiting effect of the reaction contributes to the controllability of device fabrication and the repeatability of device performance.