Minimizing DMSO Residues in Perovskite Films for Efficient and Long-Term Stable Solar Cells

Abstract

Dimethyl sulfoxide (DMSO) is commonly used as a solvent in the fabrication of perovskite solar cells. However, its strong coordination with iodoplumbate makes it difficult to remove during film formation, resulting in defects and voids at the perovskite-substrate interface, which compromise efficiency and long-term stability. Here ethyl acrylate (EA), an unsaturated monomer that aids in the effective removal of DMSO from the perovskite film is introduce. EA forms a complex with DMSO, facilitates DMSO de-intercalation, and enhances the co-evaporation process thanks to its low boiling point. Additionally, by incorporating a small amount of the initiator azobis (isobutyronitrile) (AIBN), EA is successfully polymerized into polyacrylate ethyl ester (poly-EA) during crystallization. The evaporated EA helps remove DMSO, while the poly-EA passivates defects in the perovskite films. This dual-function strategy significantly improves device performance, resulting in efficiencies of 25.4% for small-area devices and 20.3% for 15 cm² mini-modules. Moreover, poly-EA acts as a protective barrier against moisture and ion migration. Combined with improved DMSO removal, EA-modulated devices demonstrate a T₈₀ lifetime of up to 1800 h under maximum power point tracking at 55–60% relative humidity in ambient air.