Isobutyramide Additive to Improve the Performance of CsPbBr3 Perovskite Solar Cells Prepared by Green Solvent

The inorganic cesium lead bromide (CsPbBr 3 ) perovskite solar cell (PSC) is considered as an attractive option for new solar cells due to its outstanding stability. Preparing CsPbBr 3 PSCs with H 2 O can effectively save costs and reduce the harm of toxic solvents to the environment. However, the poor contact property of the PbBr 2 layer to the CsBr/H 2 O solution and the ability of water to dissolve the CsPbBr 3 phase has a significant impact on the performance of the CsPbBr 3 devices. In this article, isobutyramide is introduced into the PbBr 2 film in the first step to improve the wettability of the PbBr 2 film to CsBr/H 2 O solution, followed by spin‐coating of the 150 mg mL −1 CsBr/H 2 O solution on the PbBr 2 film. Using this strategy, the fabricated PSCs with the architecture of FTO/compact‐TiO 2 /mesoporous‐TiO 2 /CsPbBr 3 film/carbon demonstrate outstanding performance with a maximum efficiency of 9.59%. Furthermore, after 45 days of storage at ambient temperatures, the unencapsulated device retains more than 96% of its original efficiency. Therefore, this work provides a good demonstration for the preparation of high‐efficiency and eco‐friendly CsPbBr 3 PSCs.