Synergistic Effect of Additive and Solvent Vapor Annealing on the Enhancement of MAPbI₃ Perovskite Solar Cells Fabricated in Ambient Air

To date, most high-performance perovskite solar cells (PSCs) are fabricated in an inert or vacuum condition to circumvent the moisture effect, which is one of the leading causes of sparse crystal nucleation and nonuniform morphology. Therefore, it is crucial to develop a simple approach to deposit a uniform and homogeneous perovskite on a planar substrate in ambient air for the mass production of PSCs. Herein, we investigated the synergistic effect of additive 1,8-diiodooctane (DIO) and solvent vapor annealing (SVA) treatments on the performance of PSCs fabricated in ambient air. It was found that the addition of 1 vol % DIO together with SVA treatment results in the enhancement of the perovskite film's crystallinity, grain size, and photophysical properties. PSCs containing 1 vol % DIO additive and SVA treatment exhibited a power conversion of efficiency (PCE) of 17.04%, which is markedly higher than the control device with a PCE of 10.61%. The results indicate that the additive DIO and SVA can work together to significantly improve the performance of PSCs fabricated in ambient air. This work provides a promising route for developing high-performance PSCs in the ambient environment.