Simulation and optimization of all-inorganic CsSn0.5Ge0.5I3 perovskite solar cells

Abstract

Traditional perovskite solar cells use Pb-based organic–inorganic hybrid perovskites as the absorber layer and organic Spiro-OMeTAD as the hole transport layer. The toxicity of lead and the instability of organic components are significant drawbacks. This study explores a lead-free all-inorganic perovskite solar cell with CsSn_0.5Ge_0.5I₃ as the absorber layer and inorganic materials as charge transport layers. After model validation, the impacts of thickness, doping concentration, and defect density of the absorber and hole transport layer on cell performance were systematically studied. Additionally, the effects of the valence band offset between the absorber and hole transport layers and the back electrode work function were explored. Through systematic optimization, the solar cell achieved a power conversion efficiency of 30.09%, a short-circuit current density of 27.73 mA cm⁻², an open-circuit voltage of 1.23 V, and a fill factor of 88.20%. This study provides insights for the development of efficient, low-cost, and stable lead-free perovskite solar cells.