Hydrostatic Pressure-Driven Insights into Structural, Electronic, Optical, and Mechanical Properties of A3PCl3 (A = Sr, Ba) Cubic Perovskites for Advanced Solar Cell Applications

This study explores lead-free cubic perovskites Sr₃PCl₃ and Ba₃PCl₃ as sustainable alternatives to lead halide perovskites, focusing on their structural, electronic, optical, and mechanical properties under hydrostatic pressure (0–25 GPa) via DFT and Thermo-PW tools. Both materials transition from direct bandgap semiconductors (1.649 eV for Sr₃PCl₃ and 0.991 eV for Ba₃PCl₃) to metallic states at 25 GPa. Pressure-induced redshifts in absorption spectra, along with enhanced dielectric constant, refractive index, and reflectivity, highlight their optical tunability. Mechanical analysis confirms stability, ductility, and resilience under pressure. Additionally, the optimized DFT values were utilized in the suggested FTO/IGZO/A₃PCl₃/Cu₂O/Ni structures to simulate solar cell performance with SCAPS-1D. Using Sr₃PCl₃/Ba₃PCl₃ absorber, the devices attained a peak PCE of 26.66/27.3%, a J_SC of 22.79/51.05 mA/cm², an FF of 89.81/83.08%, and a V_OC of 1.3/0.64 V. This work demonstrates the potential of Sr₃PCl₃ and Ba₃PCl₃ perovskites as sustainable, lead-free materials for high-efficiency solar cells and tunable optoelectronic devices, leveraging hydrostatic pressure to optimize performance. Their stability and tunability make them promising for environmentally friendly energy solutions.