Components and defect density optimization of FAxMA1-xPbI3 based on simulation for high performance perovskite solar cells

Choosing FA⁺/MA⁺ mixed-ion perovskite material as the active layer of the perovskite solar cells hold out the prospect of high efficiency and high stability. In this paper, the FA⁺/MA ⁺ ratio is modified to optimize the performance of FA_xMA_1-xPbI₃-based perovskite solar cells utilizing SCAPS-1D. The results indicate that the PCE of the devices reached a minimum of 21 % when x is greater than or equal to 0.6 in FA_xMA_1-xPbI₃(FTO/NiO_x/FA_xMA_1-xPbI₃/C₆₀/BCP/Al). When x = 0.6, the impact of the bottom interface defects on the solar cell performance is dominant and the thickness of the active layer should be controlled within a range of 0.4 μm–0.8 μm, while the defect density of the layer is expected to be between 10¹³ 1/cm³ and 10¹⁴ 1/cm³. By optimizing the perovskite layer thickness, defect density and changing the type of back electrode material, the efficiency is reaching 25.74 % based on the device(FTO/NiO_x/FA₆MA₄PbI₃/C₆₀/BCP/Au). This study provides theoretical guidance for experimental research on interface modification, defect passivation and manufacturing of high-efficiency FA_xMA_1-xPbI₃-based perovskite solar cells.