Development and modeling of advanced systems Na₂SnBr₆-based perovskite solar cells: a comprehensive study on electron transport layers

This study simulates a n-i-p planar heterojunction for Na₂SnBr₆-based perovskite solar cells (PSCs)<b>,</b> with Na₂SnBr₆ as the absorber layer, fluorine-doped tin oxide (FTO) as the substrate, and In₂S₃, IGZO, and SnS₂ as electron transport layers (ETLs). Gold (Au) is used as the back contact. Na₂SnBr₆ was chosen for its low cost, non-toxicity, tunable band gap, excellent electrical properties, and stability. The SCAPS-1D simulator was employed to model the solar cell performance under AM 1.5 G light irradiation, focusing on factors like doping concentration, layer thickness, defect density, and interface defects across three device configurations: Device I (Au/Na₂SnBr₆/ In₂S₃/FTO/Al), Device II (Au/ Na₂SnBr₆/IGZO/FTO/Al), and Device III (Au/ Na₂SnBr₆/SnS₂/FTO/Al). Device III achieved the highest PCE of 31.35%, FF of 85.95%, V_OC of 0.7926 V, and J_SC of 46.01 mA/cm²², making it a promising candidate for high-efficiency, lead-free perovskite solar cells. Devices I and II showed lower efficiencies of 27.47% and 30.98%, respectively. The study also analyzed quantum efficiency (QE), carrier dynamics, and recombination rates, highlighting the potential of Device III in advancing Na₂SnBr₆-based hybrid perovskite solar technologies for future solar energy applications.