Enhancement of efficiency of (FA)2BiCuI6 based perovskite solar cells with inorganic transport layers

In this study, a computational modelling of PSCs with the halide double perovskite (FA)2BiCuI6 as the light harvesting layer is done by choosing a number of inorganic electron and hole transport materials for the design of the device configuration. The device configuration FTO/STO/(FA)2BiCuI6/Zn2P3/Au exhibits the best photovoltaic performance with a fill factor (FF) of 70.65% and a power conversion efficiency (PCE) of 18.25%. The solar cell configuration FTO/STO/(FA)2BiCuI6/Zn2P3/Au is modelled further to estimate the optimum input parameters of the (FA)2BiCuI6 layer. The optimum thickness, defect density and the dopant density of the (FA)2BiCuI6 layer are 716.9 nm, 1.0 × 1013 cm−3 and 1.0 × 1016 cm−3 respectively. The optimum operating temperature of the device configuration is identified to be 300 K. The device configuration requires a low value of series resistance (5 Ω cm2) and a high value of shunt resistance (8000 Ω cm2) to deliver maximum possible photovoltaic performance parameters. The device configuration is further optimized by replacing the popular back contact metal Au with other metals having suitable work functions. The device configuration FTO/STO/(FA)2BiCuI6/Zn2P3/Se with the same absorber and transport layers, but with the back metal contact Se provides a FF and a PCE of 69.92% and 18.49% respectively, indicating that Se with a high work function of 5.9 eV can be used as a suitable metal at the back contact for PSCs with the halide double perovskite (FA)2BiCuI6 as the absorber layer. •The halide double perovskite (FA)2BiCuI6 was chosen for the modelling using SCAPS 1D software tool.•Inorganic electron and hole transport layers were used for modelling.•A high theoretical Power Conversion Efficiency of 18.49% was achieved with Se as the back contact metal.•The input parameters of the absorber layer were found to have influence on the device performance.