First-Principles insights and SCAPS-1D simulations for optimizing MASnBr₃-based perovskite solar cells

This study reports computational analysis to investigate lead-free organic–inorganic CH3NH3SnBr3 (MASnBr3)-based perovskite solar cells (PSCs). The optoelectronic properties of MASnBr3 were investigated using density functional theory (DFT) with first-principles calculations, highlighting its potential for solar cell applications. The perovskite material has a band gap of 1.25 eV, with photon absorption starting above 2 eV. The extinction coefficient is maximum at 17 and 23 eV, while optical conductivity has the highest values between 15–25 eV. Reflectivity is high from 19-25 eV, and energy loss is minimal in the visible range, crucial for efficient solar cells. The value of the refractive index is 1.65 eV at the photon energy of 0 eV. Device optimization through simulations explored optimized parameters such as layer thickness, defect density, and different charge transport layers, resulting in a remarkable enhancement in the power conversion efficiency (PCE). The PCE reached 22.71 % while using the optimized parameters of PSC with V_OC of 0.56 V, J_SC of 42.68 mAcm⁻², and FF of 77 %. Moreover, this study focuses on the influence of the working temperature (WT), series resistance (R_series), and shunt resistance (R_shunt) on the device performance. Hence, high efficiency in MASnBr₃-based PSCs can be further achieved by carefully optimizing the photovoltaic parameters and effectively managing the defect densities.