Low‐Coordination Solvation Engineering Enables Efficient and Stable Perovskite Solar Cells

The solvation chemistry of perovskite precursor solutions plays a pivotal role in perovskite crystallization, exerting a significant influence on the performance and stability of devices. As such, the selection of the solvent is of utmost importance. Dimethyl sulfoxide and dimethylformamide, characterized by high Gutmann donor numbers, form strong coordinate bonds with perovskite precursors, thereby retarding perovskite crystallization. Nevertheless, the substantial desolvation activation energy associated with these solvents gives rise to elevated defect concentrations in the resultant perovskite films. In this study, we introduce dimethyl carbonate (DMC), a sustainable solvent with a lower Gutmann donor number that establishes weaker coordination with perovskite precursors. The interactions between DMC and PbI 2 /FAI facilitate the formation of smaller colloidal particles, prolonging the shelf‐life of the precursor solution. Furthermore, the incorporation of DMC enhances the quality of perovskite films, optimizes energy‐level alignment, and improves charge carrier transport and extraction. Consequently, devices treated with DMC exhibit a power conversion efficiency of 25.53%, alongside enhanced long‐term stability.