Crystalline orientation control using self-assembled TiO₂ nanosheet scaffold to improve CH₃NH₃PbI₃ perovskite solar cells

In perovskite solar cells with an organic inorganic hybrid metal halide perovskite crystalline semiconductor as the active layer, the properties of the n-type semiconductor scaffold, the materials used, and the morphology, wettability, and surface reactivity of the cells are important decisive factors affecting the overall device efficiency of the perovskite solar cells. We control the orientation of anatase titania nanosheets by a self-assembly technique to create the ordered mesoporous scaffolds with ordered voids. Differences between nanosheet orientations in each mesoporous scaffold indicate differences in the photoelectric properties of CH₃NH₃PbI₃ perovskite crystals embedded in each scaffold. Although each scaffold consists of the same anatase TiO₂ nanosheets, the properties of the solar cells are affected by the oxide scaffold nanomorphology, which determines the growth orientation of CH₃NH₃PbI₃ perovskite crystals that affects the solar cell properties.