Theoretical analysis of stability, physical properties, and photovoltaic potential of Sr3SbCl3 perovskite across varying pressure conditions via DFT and SCAPS-1D

The exceptional stability and tunable physical properties of inorganic perovskite-based materials have attracted significant interest in solar energy applications. We investigated the stability of Sr₃SbCl₃, assessing its structural, thermodynamic, dynamical, and mechanical properties. Using FP-DFT simulations in CASTEP, we comprehensively analyzed the impact of pressure on its physical characteristics. The direct band gap of unstrained Sr₃SbCl₃ at the Γ point is 1.908 eV. Under pressure, it decreases to 1.518 eV at 5 GPa, 1.174 eV at 10 GPa, and further redshifts to 0.863 eV at 15 GPa. The optical properties, such as dielectric functions, absorption coefficient, refractive index, loss functions, reflectivity, and, conductivity, demonstrate a significant ability to absorb light within the visible spectrum, aligning with the material's band characteristics. To investigate solar power capabilities, we examined Sr₃SbCl₃ absorbers in conjunction with CdS ETL of varying thicknesses, defect densities, acceptor densities, interface defect densities, and temperature effect using the SCAPS-1D simulator. The efficiency starts at 15.71 % without pressure, rising to 23.00 % at 5 GPa and peaking at 30.01 % at 10 GPa before declining to 25.53 % at 15 GPa. The optimal configuration at 10 GPa pressure yielded a FF of 82.69 %, a J_SC of 40.329 mA/cm², an V_OC of 0.90 V, and a PCE of 30.01 %. These results support further exploration of Sr₃SbCl₃ as a promising perovskite for optoelectronic applications.