Effects of electron transport layer type on the performance of Pb-free Cs₂AgBiBr₆ double perovskites: a SCAPS-1D...

Recently, due to the superior stability and lower risk of toxicity, the development of Pb-free halide double perovskite materials has revived excellent interest. In this work, Pb-free perovskite solar cells (PSCs) with ITO/ETL/Cs₂AgBiBr₆/Cu₂O/Au multilayer structures with Cs₂AgBiBr₆ double perovskite as the solar light absorber layer, some electron transport layers (ETLs) and Cu₂O as a hole transport layer have been introduced. Then, the effects of various thicknesses of the absorber layer and also ETL materials, like ZnO, C₆₀, CdS, SnO₂, phenyl-C₆₁-butyric acid methyl ester (PCBM), and TiO₂, on the device performance (including photoelectronic conversion efficiency (PCE), fill factor (FF%), short circuit current density (Jsc), and open-circuit voltage (V_OC)) were examined with the help of a solar cell simulator (SCAPS-1D). It is noteworthy that, in the case of all ETL materials, the optimal thickness of the absorber layer was determined to be 400 nm. Then, the maximum PCE values of 20.08%, 17.63%, 14.07%, 12.11%, 14.94%, and 18.83% were obtained for the solar cells containing ZnO, C₆₀, CdS, SnO₂, PCBM, and TiO₂ as the ETL, respectively. These results show that designing/developing Pb-free halide double perovskite devices having comparable PCEs with the Pb-based PSCs is feasible, provided that proper/compatible materials will be used in the multilayer structure of the next generations of solar cells.