The humidity-insensitive fabrication of efficient CsPbI3 solar cells in ambient air

Abstract

Recently, CsPbI₃ perovskite solar cells (PSCs) have shown a breakthrough in photovoltaic performance due to their constantly improving power conversion efficiencies (PCEs) because of their admirable photoelectric properties and enhanced thermal stability. However, most fabrication processes take place inside a nitrogen glove box because CsPbI₃ is notoriously sensitive to moisture. These tedious and rigorous operational conditions restrict CsPbI₃ PSCs' commercialization. In our research, in order to solve the awkward situation of fabricating CsPbI₃ PSCs without ambient moisture, we successfully developed an easy, one-step anti-solvent hot substrate (Anti-hot) spin-coating method to fabricate CsPbI₃ film. Pre-heating the substrate could change the saturated vapor pressure of the mixed solvents and accelerate the precursor concentrations up to the supersaturation limit. Meanwhile, the anti-solvent method could induce heterogeneous nucleation. As a result, we could efficaciously control nucleation generation and grain growth under ambient moisture conditions and resist erosion and damage by molecular water. Finally, uniform and compact CsPbI₃ film could be achieved and the corresponding PSCs reached up to 15.91% in a high humidity environment (RH, ∼50%). We hope that our exploration can provide a synthetic approach for producing high-quality CsPbI₃ film for PSCs under ambient conditions.