Efficient and Stable Perovskite Solar Cells Prepared in Ambient Air Based on Surface-Modified Perovskite Layer

Among many photovoltaic conversion technologies, perovskite solar cells have received significant research interests as effective photovoltaic materials owing to their high solar conversion efficiencies and low cost. However, the performance of perovskite solar cells is limited by the instability of CH 3 NH 3 PbI 3 to water and ambient moisture. To address this issue, in this study, we introduced a new fundamental approach that utilizes 4- tert -butylpyridine (tBP) as the surface modification agent to enhance the performance and stability of CH 3 NH 3 PbI 3 -based perovskite solar cells fabricated in ambient air. The tertiary butyl group in tBP is highly hydrophobic, leading to the formation a hydrophobic layer on the surface of CH 3 NH 3 PbI 3, thus increasing the moisture stability of perovskite solar cells. With this strategy, the performance of perovskite solar cells prepared at even >50% RH in ambient air was tremendously enhanced by as much as 200% compared to that without tBP additive. Besides, the stability of perovskite solar cells in ambient air was also markedly improved.