A comprehensive analysis of PV cell parameters with varying halides stoichiometry in mixed halide perovskite solar cells

Abstract

The optimized halide stoichiometry in mixed-halide perovskites offers the enhanced photophysical properties of perovskites films for efficient and stable perovskites solar cells (PSCs). Herein, a comprehensive analysis of the impact of the variation of cationic bromide (CH3NH3Br or MABr) concentration on the performance parameters of mixed halide (MAPbI(3-x)Br(x)) PSCs have been presented. It was noted that with an increase of MABr concentration from 10 to 70 mg/ml, open-circuit voltage (V-oc) increases from 942 mV to 992 mV, short circuit current density (J(sc)) decreases from 19.83 mA/cm(2) to 12.36 mA/cm(2). Device having 20 mg/ml MABr exhibits best performance with an efficiency eta = 12.18%, V-oc = 0.96 V, J(sc) = 18.99 mA/cm(2) and fill factor (FF) = 0.67. Furthermore, photovoltaic (PV) cell parameters, i.e., J(ph), R-sh, R-s, n, and J(0) were analytically extracted and analyzed to recognize the influence of MABr. The best performing devices exhibits a higher photocurrent density: J(ph) = 19.16 mA/cm(2), optimum device resistances: R-sh=869.57 Omega-cm(2), R-s = 7.91 Omega-cm(2), minimum value of ideality factor n = 1.52 and negligible leakage current density: J(0) = 3.95 x 10(-13) mA/cm(2). The predicted PV cell parameters suggest that the best performing device possesses optimum morphology, lowest leakage current, and reduced recombination of charge carriers.