Controlled Growth of Porous InBr: PbBr Film for Preparation of CsPbBr in Carbon-Based Planar Perovskite Solar Cells.

Due to the low solubility of CsBr in organic solvents, the CsPbBr film prepared by the multi-step method has holes and insufficient thickness, and the light absorption capacity and current density of the perovskite film hinder the further improvement in the power conversion efficiency (PCE) of CsPbBr solar cells. In this study, we introduced InBr into the PbBr precursor solution and adjusted the concentration of PbBr, successfully prepared PbBr with a porous structure on the compact TiO (c-TiO) substrate to ensure that it fully reacted with CsBr, and obtained the planar carbon-based CsPbBr solar cells with high-quality perovskite film. The results reveal that the porous PbBr structure and the increasing PbBr concentration are beneficial to increase the thickness of the CsPbBr films, optimize the surface morphology, and significantly enhance the light absorption capacity. Finally, the PCE of the CsPbBr solar cells obtained after conditions optimization was 5.76%.