Abstract

Bismuth halide perovskites shows excellent replacement of Lead due to safer with high chemical stability and exhibits similar optoelectronic properties. Experimental examinations have been done only for MA3Bi2I9 and FA3Bi2I9 compounds which had only one halide. Herein, we investigated MA3Bi2IxCl9-x (x = 3) (labelled as MBIxCl9-x) and FA3Bi2IxCl9-x (x = 3) (labelled as FBIxCl9-x) lead free perovskites with mixed halides for photovoltaic applications. By incorporating the Cl- halide anion into the MBIxCl9-x (x = 3) and FBIxCl9-x (x = 3) led to remains unchanged crystal structure and enhancement of the surface morphology of the thin films. Increasing the absorption in visible region of MBIxCl9-x (x = 3) and FBIxCl9-x (x = 3) are 628 nm and 650 nm with lowering the band gap of 1.85 V and 1.56 eV respectively. The prominent photo emission spectra are obtained at 654 nm and 658 nm for MBIxCl9-x (x = 3) and FBIxCl9-x (x = 3) respectively which reducing the rate of recombination. The thermal stability of both perovskites is investigated, up to 230? C and 232? C could sustained without weight loss occurs. Nyquist plot confirmed that MBIxCl9-x (x = 3) perovskite have higher recombination resistance Rrec value than FBIxCl9-x (x = 3) which led to the reduction of rate of recombination of charge carriers at interface layers. MBIxCl9-x (x = 3) and FBIxCl9-x (x = 3) perovskites solar cells has produced Power Conversion Efficiency (PCE) of 0.078 % and 0.016 % with open circuit voltage (Voc) of 0.410 V and 0.239 V, short circuit current density (Jsc) of 0.623 mA/cm2 and 0.234?A/cm2 respectively. © 2025 Elsevier B.V.