High‐Performance Perovskite Solar Cells via Green Antisolvent Ethyl Methyl Carbonate

The one‐step antisolvent method is an important approach for preparing high‐quality perovskite films and high‐performance perovskite solar cells (PSCs). However, the main solvents N,N‐dimethylformamide (DMF) and antisolvent chlorobenzene (CB) commonly used in this process are highly volatile toxic, which pose a serious threat to environmental safety and human health, and are not conducive to the commercialization of PSCs. Therefore, we have developed a new perovskite precursor solution system to prepare high‐quality FA 0.9 Cs 0.1 PbI 3 perovskite films. We used a less toxic N‐methylpyrrolidone (NMP) as the solvent and a green ethyl methyl carbonate (EMC) as the antisolvent. The morphology of perovskite films prepared with EMC antisolvent and the typical green antisolvent ethyl acetate (EA) and the performance of the corresponding PSCs were compared. It's found that EMC‐processed perovskite films have better crystallinity with fewer defects. Also, with better energy level alignment, the EMC‐processed PSCs achieved a photoelectric conversion efficiency (PCE) of 19.68%, much higher than that of EA‐processed PSCs (17.98%).