SCAPS-1D Study of Pioneering $\text{Li}_{2}\text{AgBiZ}_{6}$ (Z=C1, Br, I) Absorbers in Lead-free Double Perovskite Solar Cells

Lead-free Double Perovskite Solar Cells (DPSCs) have recently attracted considerable research interest due to their potential as an effective perovskite absorber layer in device architecture, coupled with their affordability, exceptional stability, and high performance. In this work, we report the numerical investigation of employing <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Li}_{2}\text{AgBiZ}_{6}$</tex> (Z = C1, Br, and I) as pioneering absorber layers using SCAPS-1D. Effects of absorber layer thickness, doping density of states, defect densities of states within the absorber layer and at ETL and HTL interfaces, metal work function, operational temperature on current density - voltage and quantum efficiency characteristics were analyzed. The effects of different halide ions on device parameters were also evaluated. Maximum efficiencies of 7.05%, 15.73%, and 15.87 % were obtained with total enhancements in performance of 26%, 19 %, and 45 % compared to those of initial structures for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Li}_{2}\text{AgBiCl}_{6},\text{Li}_{2}\text{AgBiBr}_{6}$</tex>, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Li}_{2}\text{AgBiI}_{6}$</tex>, respectively. Optimal structure was found to be Au/Spiro-OMeTAD/ <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Li}_{2}\text{AgBiZ}_{6}/\text{TiO}_{2}/\text{FTO}$</tex>. These results offer a promising pathway for developing more efficient and environmentally friendly photovoltaic technologies, which are crucial for advancing sustainable energy solutions.