Enhancing perovskite solar cell performance using a BaSnS₃ chalcogenide perovskite: a device simulation study

This study explores the potential of BaSnS₃, a tin-based chalcogenide perovskite, as a lead-free absorber material using density functional theory (DFT), where the hybrid functional HSE06 is utilized to investigate its structural, electronic, and optical properties. This compound exhibits dynamic stability with no imaginary phonon frequencies and possesses an indirect bandgap of 1.535 eV, making it well-suited for photovoltaic applications. Its favorable optical characteristics including a high absorption coefficient exceeding 10⁵ cm^-1 in the visible range and a static dielectric constant of 8.55 (unitless, relative to vacuum permittivity) further affirm its suitability as a solar absorber. In addition, comprehensive device simulations using SCAPS-1D are performed to evaluate the photovoltaic performance of BaSnS₃-based perovskite solar cells (PSCs) with various electron transport layers (ETLs) including ZnS, SnS₂, C₆₀, and LBSO. The ITO/ZnS/BaSnS₃/Pt structure demonstrates the highest efficiency, achieving a power conversion efficiency (PCE) of 25.93%, an open-circuit voltage (V _OC) of 1.136 V, and a short-circuit current density (J _SC) of 26.65 mA cm^-2. The influence of the absorber and ETL thickness, defect density, series and shunt resistances, and operating temperature on the cell performance is systematically analyzed. The findings reveal that the optimized absorber thickness (1.0 µm) and minimized defect density significantly enhance the efficiency. Furthermore, its temperature sensitivity and recombination dynamics are examined through quantum efficiency (QE), J-V analysis, and Mott-Schottky profiling. This combined theoretical and numerical investigation not only highlights BaSnS₃ as a promising candidate for future lead-free PSCs but also provides a foundation for further experimental validation and device engineering.