Design and investigate the performance of lead-free double absorber perovskite solar cell using Cs₂CuBiBr₆ and Cs₄CuSb₂Cl₁₂ with optimized ETLs

The photovoltaic system typically utilizes perovskite solar cells (PSCs) due to their specialness characteristics. (PSCs) are safe, whereas lead-based absorbers are harmful, limiting their production. Halide perovskites are an attractive candidate for high-efficiency photovoltaic materials; they possess characteristic optical properties, high efficiency, low cost, and a lightweight structure. As such, research on the topic of perovskite materials is currently revolving around research on lead-free perovskites. The study tests a solar cell with two absorbers, Cs 2 CuBiBr 6 at the base and Cs₄CuSb₂Cl₁₂ at the bottom using SCAPS-1D modeling. The main aim is to optimize the device setting so as to achieve maximum efficiency of Cs 2 CuBiBr 6 . To do this, the two active layers were varied in terms of their thicknesses in order to reach matching current and a number of electron transports layers WS 2 , C 60 , In 2 S 3 , SnS 2 , IGZO, PCBM and TiO 2 with Au and Al as the back and front contact metals, respectively. The paper examines how parameters, including electron transport layers, absorber, temperature, thickness, defect density, metal work functionality, series and shunt resistances, affect the performance of the device. The power conversion efficiency (PCE) of the device is 30.44%, 28.66%, 21.34%, 29.51%, 29.49%, 30.25% and 30.38% for WS 2 , C 60 , In 2 S 3 , SnS 2 , IGZO, PCBM and TiO 2 respectively. The reported efficiency represents an ideal simulated upper limit under optimized conditions. The effect of absorber thickness is also pointed out in this research. This investigation also covered the study of the valence band offset (VBO) and conduction band offset (CBO). We also researched the density voltage (JV), quantum efficiency (QE), series and shunt resistance, capacitance-Mott-Schottky properties, and rates of photocarrier generation, recombination, and effective temperature. The research will offer important structural design principles of a lead-free double absorber two perovskite system of Cs 2 CuBiBr 6 and bring out the developments in solar energy optoelectronics.