Influence of lead (II) chloride and/or lead (II) bromide entrance on the efficiency and stability of methyl ammonium lead triiodide perovskite solar cell: Comparative study of the halide composition and substitution percentage

In this research, various amount of PbBr₂ and PbCl₂ in some parts of PbI₂ in the methyl ammonium lead triiodide (MAPbI₃) perovskite composition, named [MAI (PbI₂)₁–_Y (PbX₂) _Y; X: Br, Cl, and Y: 3%, 5%, and 10%] were substituted by the one-step solution method. The crystallographic structure of the as-prepared perovskite films was investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). A comparative evaluation about the influence of the lead halide type and substitution percentage on the optical and electronic properties of the prepared perovskites in the perovskite solar cells (PSCs) were done using current density-voltage curves (J-V), electrochemical impedance spectroscopy (EIS), and photoluminescence (PL) techniques. The best photovoltaic performance and stability of fabricated MAI (PbI₂)₁–_Y (PbBr₂) _Y-based and MAI (PbI₂)₁–_Y (PbCl₂) _Y-based cells were obtained at 5% PbBr₂ and 3% PbCl₂ doping, respectively. The MAI (PbI₂)₁–_Y (PbBr₂) _Y-based PSCs showed higher photovoltaic and stability performances than MAI (PbI₂)₁–_Y (PbCl₂) _Y-based cells. The highest power conversion efficiency (PCE) of 17.14% with an open-circuit voltage (V_oc) of 1.06 V, a short-circuit photocurrent density (J_sc) of 22.61 mA/cm² and a fill factor (FF) of 0.72 was achieved for the MAI (PbI₂)₁–_Y (PbBr₂) _Y-based PSC at the Y = 5%.