“In the field of perovskite solar cells, researchers have found through Huck's theory calculations that carbonyl oxygen in N-ethyl-2-pyrrolidone (NEP) has stronger electronegativity than N-methylpyrrolidone (NMP), predicting its stronger interaction with PbI2. By replacing NMP in the solvent with NEP, the crystallization quality of perovskite thin films was effectively improved. The highest photoelectric conversion efficiency (PCE) of the prepared FAPbI3 perovskite solar cell increased from 20.25% to 21.05%, and the average efficiency increased from 18.43% to 19.50%. Under the conditions of relative humidity of 10% to 20% and room temperature, the unpackaged device can still maintain 82.1% of its initial efficiency after 1200 hours. This strategy is also applicable in the solution system of double cation component (FA0.95Cs0.05PbI3) perovskite precursor, demonstrating certain universality and contributing to the research on the preparation of perovskite solar cells in air environments.”