Colloidal Stabilizer‐Mediated Crystal Growth Regulation and Defect Healing for High‐Quality Perovskite Solar Cells

Abstract High‐quality perovskite (PVK) films is essential for the fabrication of efficient and stable perovskite solar cells (PSCs). However, unstable colloidal particles in PVK suspensions often hinder the formation of crystalline films with low defect densities. Herein, ethylenediaminetetraacetic acid (EDTA) as a colloidal stabilizer into lead iodide (PbI₂) is introduced colloidal solutions. EDTA forms chelated complexes with Pb²⁺, enhancing the electrostatic repulsion and steric hindrance between colloidal particles. This stabilizes the particles and inhibits disordered motion (Brownian motion) and excessive aggregation. As a result, PbI₂ films with a uniform hole distribution are formed, providing ample pathways for subsequent PVK film growth and sufficient space. During the film formation process, the replacement of molecules by formamidinium iodide (FAI) and EDTA slows down crystallization, ultimately leading to PVK films with large grain sizes and low defect density. By using this approach, champion power conversion efficiencies (PCEs) of 24.05% for FA_0.97Cs_0.03PbI₃ PSC, 11.08% for CsPbBr₃ PSC, and 25.19% for FA_0.945MA_0.025Cs_0.03Pb(I_0.975Br_0.025)₃ PSC are achieved. Moreover, the EDTA‐based FA_0.97Cs_0.03PbI₃ device retains over 90% of its initial PCE after 1000 h at the maximum power point (MPP) under continuous illumination.