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 (MAPbI3-xBrx) PSCs have been presented. It was noted that with an increase of MABr concentration from 10 to 70 mg/ml, open-circuit voltage (Voc) increases from 942 mV to 992 mV, short circuit current density (Jsc) decreases from 19.83 mA/cm2 to 12.36 mA/cm2. Device having 20 mg/ml MABr exhibits best performance with an efficiency η = 12.18%, Voc = 0.96 V, Jsc = 18.99 mA/cm2 and fill factor (FF) = 0.67. Furthermore, photovoltaic (PV) cell parameters, i.e., Jph, Rsh, Rs, n, and J0 were analytically extracted and analyzed to recognize the influence of MABr. The best performing devices exhibits a higher photocurrent density: Jph = 19.16 mA/cm2, optimum device resistances: Rsh=869.57 Ω-cm2, Rs = 7.91 Ω-cm2, minimum value of ideality factor n = 1.52 and negligible leakage current density: J0 = 3.95 × 10−13 mA/cm2. The predicted PV cell parameters suggest that the best performing device possesses optimum morphology, lowest leakage current, and reduced recombination of charge carriers.
[Display omitted]
•Via regulating the halide stoichiometry, the performance of the PSC was improved.•The CH3NH3Br of 20 mg/ml concentration delivered the best performance.•The losses in the devices were analyzed using PV cell parameters.•The performance of PSC was enhanced by the reduction in the charge recombination.•The obtained lowest values of n and J0 were 1.52 and 3.95 × 10−13 A/cm2, respectively.