Exploring the influence of hydrostatic pressure on the structural and optoelectronic behavior of cubic A3PCl3 (A = Mg, Ca) perovskite for solar cell applications

This study utilizes first-principles simulations to investigate the optoelectronic properties of lead-free halide A₃PCl₃ (A = Mg, Ca) perovskites subjected to hydrostatic pressures from 0 to 60 GPa. As pressure increases, both the lattice parameter and cell volume decrease, indicating structural compression of the material. At ambient pressure, Mg₃PCl₃ and Ca₃PCl₃ demonstrate band gaps of 2.227 eV and 1.801 eV, respectively, indicating their potential for optoelectronic applications. The materials meet the Born stability criteria for mechanical stability throughout the examined pressure range, thereby confirming their stability under hydrostatic conditions. The perovskites demonstrate anisotropic elastic properties and possess high ductility, mechanical stability, and resistance to plastic deformation, all of which are improved under pressure. The mechanical analysis indicates that the materials maintain ductility and mechanical stability, exhibiting increased ductility with rising pressure. The optical properties were computed over the 0–35 eV energy spectrum under multiple pressures. Additionally, the optimized DFT values were employed in the proposed device construction FTO/ZnO/Mg₃PCl₃/Cu₂O/Ni and FTO/ZnO/Ca₃PCl₃/Cu₂O/Ni configurations attained optimal power conversion efficiencies (PCE) of around 15.29 % and 23.2 %, respectively, providing a safer, lead-free alternative to conventional Pb-based perovskites. Both materials exhibit remarkable ductility and compressive resistance, with bulk moduli substantially exceeding those of other perovskites such as CsPbX₃ and Sr₃AsCl₃. The amalgamation of mechanical stability, superior ductility, and pressure resilience renders Mg₃PCl₃ and Ca₃PCl₃ exemplary candidates for applications necessitating both high optoelectronic performance and durability under fluctuating pressure conditions.