Hybrid Low-Dimensional Perovskites Passivation for Efficient Two-Step Assistance-Free Blade-Coated FAPbI3 Solar Cells

Abstract

Scalable deposition of high-efficient PSCs is crucial for accelerating their commercial application. However, in two-step blade coating process, the incomplete reaction between organic salts and the predeposited PbI₂ layer leads to a large amount of excess PbI₂, which is detrimental to the efficiency and long-term stability of perovskite films. Phenethylammonium iodide (PEAI) can convert residual PbI₂ into 2D perovskite, which is an effective strategy for improving the performance of perovskite. However, there is still a significant amount of residual PbI₂ after treatment. Benzamidine hydrochloride (PFACl) has been proven to easily react with residual lead iodide to form 1D perovskite, significantly reducing the residual lead iodide. In this work, it combines PEAI with PFACl to develop a novel 1D/2D low-dimensional perovskite composite structure. By using the 1D perovskite with lower reaction energy and 2D perovskite in synergy, this work more effectively removes residual lead iodide, thus achieving a two-step blade coating process for perovskite preparation without additional assistance. In small-area PSCs, the efficiency of PFACl/PEAI treated PSCs increases from 20.5% to 22.71%. Additionally, the encapsulated devices treated with PFACl/PEAI maintain 91% of their initial efficiency after being stored in dry air for 1440 h.