Conversion of metal-organic halide perovskite from PbI2 precursor films grown by hot-wall method

We report on metal-organic halide perovskite CH3NH3PbI3 films converted from PbI2 precursors for planar heterojunction perovskite solar cells. PbI2 films as a precursor were deposited by hot-wall method and conventional vacuum evaporation. The conversion to perovskite phase from the PbI2 films were performed by annealing in methyl ammonium iodine (MAI) vapour at 120-150 °C. We confirmed that no residual PbI2 phase can be detected in the converted perovskite films by x-ray diffraction measurements. The surface morphology of the perovskite films was measured by AFM. Roughness Ra of the films is 17.8 nm, which is comparable value to the reported ones. Using the converted perovskite films we fabricated tentative perovskite solar cells with a device architecture of ITO/PEDOT:PSS/Perovskite/C60/Ag. The power conversion efficiencies of the fabricated solar cells from a conventional evaporation and the hot-wall method exhibited 2.22 and 2.33%, respectively