Lead free CsSn_0.5Ge_0.5 I₃ perovskite solar cell with different layer properties via SCAPS-1D simulation

Organic-inorganic halide perovskite solar cells (PSCs) have been extensively studied due to their simple fabrication methods and obvious device efficiency advantages. In this work, the perovskite CsSn0.5Ge0.5I3 is used as the light absorption layer, which is doped with Ge2+ in CsSnI3 to improve its stability. The polymers of 3-hexylthiophene (P3HT) with excellent optoelectronic properties and low price, and SnO2 with high electron extraction ability is selected as charge transport layers. Based on these, a novel PSC structure (FTO/SnO2/IDL1/CsSn0.5Ge0.5I3/IDL2/P3HT/Au) has been simulated via solar cell capacitor simulator (SCAPS-1D). The PSC performance is optimized by adjusting a series of parameters, including the layer thickness, defect density, electron affinity potential energy, and operating temperature, and so forth. The results show that the PSC defects are passivated by adjusting the appropriate parameters, and the final optimized open circuit voltage (V-OC) is 1.08 V, short-circuit current density (J(SC)) is 27.37 mA/cm(2), fill factor (FF) is 83.32%, while the power conversion efficiency (PCE) is increased from the initial 10.89% to 24.63%, which provides theoretical reference for experiments and new ideas for the preparation and development of efficient and environmentally friendly PSCs. Finally, the effect of different metal cathodes with and without hole transport layer (HTL) on PSC performance is compared. The PSCs without HTL are more dependent on battery cathodes, which provided a way to replace precious metals with other electrode materials.