Iodine Induced PbI2 Porous Morphology Manipulation for High-Performance Planar Perovskite Solar Cells

The quality of the perovskite film has a vital influence on the performance of perovskite solar cells and it is quite desirable to simultaneously manipulate the crystallization and morphology of the perovskite film. In this study, conventional PbI 2 is replaced with a PbI 2 /I 2 mixed precursor during the first step of sequential deposition, causing the formation of a PbI 2 porous nanostructure. By changing the content of I 2 in the precursor, the morphology of the PbI 2 film as well as the resulting perovskite film can be successfully modulated. With an optimal content of I 2 , a high-quality perovskite film with a pure phase and smooth surface can be achieved. As a result, the conversion efficiency of perovskite solar cells using a PbI 2 /I 2 mixed precursor can be as high as 18.63%, compared to 16.89% for the reference device through traditional sequential deposition with a pure PbI 2 precursor.