Lead halide and inorganic double perovskite solar cells: enhancing efficiency through theoretical simulation

• Replacing C60 ETL with ZnO in a specific configuration significantly improved electron extraction, increasing the PCE to 20.68%. • An ultrathin Al 2 O 3 buffer layer was introduced to stabilize the perovskite/ZnO interface and enhance device durability. • Structural optimization, including ETL selection, triple-HTL stacking, and perovskite-layer tuning, further boosted device efficiency • Substituting ITO/Ca with FTO as the transparent electrode contributed to additional efficiency gains. • The optimized CH 3 NH 3 PbI 3 -based PSC achieved a PCE of 22.36%. • A lead-free all-inorganic Cs 2 PtI 6 double-perovskite device exhibited an efficiency exceeding 22%, highlighting its potential as a highly stable, non-toxic cell. In this study, a computational platform for optoelectronic modeling has been applied for optimization of perovskite solar cells (PSCs). The thicknesses of the electrodes, transport layers, and perovskite absorber layer were optimized theoretically. The investigation focused on the effects of material selection and structural optimization in CH 3 NH 3 PbI 3 and Cs 2 PtI 6 -based PSCs. The efficiency of a reference device with the configuration of Glass/ITO/Ca/C 60 /CH 3 NH 3 PbI 3 /TAPC/TAPC:MoO 3 /MoO 3 /Ag was optimized by replacing the C 60 ETL with zinc oxide (ZnO). The new configuration with ZnO included an ultrathin Al 2 O 3 buffer layer to overcome the effect of ZnO on perovskite. Additionally, using FTO as the transparent electrode improved efficiency further. The optimized configuration of Glass/FTO/ZnO/Al 2 O 3 /CH 3 NH 3 PbI 3 (436 nm)/TAPC/TAPC:MoO 3 /MoO 3 /Ag achieved a PCE of 22.36%. Additionally, based on the optimized configuration, another cell using the nontoxic, stable, lead-free all-inorganic double perovskite Cs 2 PtI 6 achieved an efficiency exceeding 22%. These results highlight that material selection and geometrical optimization are vital strategies for realizing high-efficiency perovskite solar cells.