Numerical analysis of K₂CuBiBr₆ for enhanced solar cell performance potential

Abstract This study investigates the potential of K 2 CuBiBr 6 as a light-absorbing material in perovskite solar cells (PSCs). The simulated device structure, modeled using the SCAPS-1D tool, comprises ITO/BaSnO 3 /K 2 CuBiBr 6 /NiO/Au. Optimization of the device parameters, including absorber layer thickness, bulk defect density, and interface defect density, yielded a maximum efficiency of 14.7% with an open-circuit voltage ( V oc ) of 0.98 V, short-circuit current density ( J sc ) of 29.20 mA cm −2 and a fill factor (FF) of 55.88% under the AM1.5 spectrum. The optimized configuration was achieved at an absorber layer thickness of 700 nm, a bulk defect density of 1 × 10 13 cm −3 , and the charge transport layer-perovskite interface defect density of 1 × 10 14 cm −2 . Furthermore, the device performance was analyzed under varying conditions of series resistance, shunt resistance, and operating temperature. The efficiency remains ∼15.4% for the shunt resistance of more than 10 4 Ω and series resistance of 1 Ω at room temperature. Comparative evaluation of seven-hole transport layer materials and ten electron transport layer materials identified BaSnO 3 and NiO as the most suitable candidates for their respective roles. This study highlights the feasibility of employing double perovskites like K 2 CuBiBr 6 in PSCs, offering a pathway toward high-efficiency and stable solar cell designs.