Cs incorporation via sequential deposition for stable and scalable organometal halide perovskite solar cells

In this study, uniform Cs distribution in an organometal halide perovskite (OHP) film was achieved via sequential deposition method entailing the dissolution of Cs compounds in dimethyl formamide (DMF) with inorganic components, as opposed to using isopropyl alcohol with organic components, and the thermal stability and crystallinity of the OHP film were enhanced by improving the structural stability through Cs incorporation. Additionally, the device performance and thermal stability of OHP solar cells were enhanced by Cs incorporation, which led to fewer defect sites and the suppression of defect generation in OHP films, as confirmed by optical and electrical analysis, improving the overall film quality. The sequential deposition method was more amenable to scaling up than the anti-solvent assisted one-step spin-casting method, as demonstrated by the sequential deposition of the OHP film uniformly over a substrate with size of 8 cm × 8 cm. The uniformly sequentially deposited OHP film was used to create a large-area 1 cm2 OHP solar cell, which exhibited a high power conversion efficiency (PCE) of 16.77%. Further scalability of the sequentially deposited OHP solar cell was confirmed by highly uniform device performances by three cells on a single substrate with a negligible PCE standard deviation of 0.94%.