Exploring Multi‐Level ETL and HTL Configurations for High‐Efficiency Lead‐Free Cs2AgBiBr6 Double Perovskite Solar Cells: A Design and Simulation Study.

Cs2AgBiBr6 is a promising lead‐free double perovskite solar cells (PSCs) material. Its full potential has yet to be realized due to issues with its large band gap and the optimization of the alignment of the electron transport layer (ETL) and hole transport layer (HTL). The photovoltaic performance of Cs2AgBiBr6‐based devices has been optimized using ZnO, IGZO, TiO2, WS2, PCBM, and C60 ETLs and Cu2O, CuScN, CuSbS2, NiO, P3HT, PEDOT: PSS, Spiro MeOTAD, CuI, CuO, V2O5, CBTS, and CFTS HTLs. It has been observed by simulation study that Cs2AgBiBr6‐based devices exhibit remarkably high photoconversion efficiency when combined with certain ETLs. To better understand the performance, we examine how the best device structures are affected by the absorber and ETL thickness, ETL carrier density, series and shunt resistance, generation, and recombination rate. The findings suggest that TiO2 and ZnO ETLs, in conjunction with CBTS HTL, exhibit good potential for producing high‐efficiency (η > 13%) Cs2AgBiBr6‐based heterojunction solar cells with an ITO/ETL/Cs2AgBiBr6/CBTS/Au device structure. Optimization of the valence band offset (VBO) at the CBTS/Cs2AgBiBr6 interface reveals that reduced VBO value has a beneficial impact on the performance of the solar cell. This modeling work gives a prospective route for manufacturing lead‐free Cs2AgBiBr6 PSCs. [ABSTRACT FROM AUTHOR]