Effect of a Doping Gradient on the Performance of HTL-Free Mixed-Halide Perovskite Solar Cells: A Simulation Study

This study examines a perovskite solar cell with HTL-free arrangement, using Cs0.05(FA0.77MA0.23)0.95Pb(I0.77Br0.23)3 as the absorber and TiO2 as the electron transport layer (ETL). The photovoltaic performance of the solar cell is assessed using the SCAPS-1D software tool by varying several parameters such as doping concentration gradients, layer thickness, defect density, and the number of subdivided layers. The results indicate that the doping gradients in the perovskite absorber exert the most significant influence on efficiency, underscoring the critical role of layer engineering. The optimal value of doping gradient results in 30% enhancement in power conversion, in comparison to uniform doping. The efficiency for power conversion for the optimized configuration is found equal to 21.77% and the corresponding values of the open-circuit voltage, short-circuit current and fill factor are 1.16 V, 21.32 mA cm–2, and 87.46%, respectively. These insights provide a foundation for future advancements in material optimization, stability improvement, and scalable fabrication, driving the development of next-generation perovskite solar technologies.