Investigating the Impact of Interfacial Layers on Device Performance of Highly Stable Cs₂InBiBr₆ Based Double Perovskite Solar Cells

Perovskite solar cells, a third-generation photovoltaic technology, have recently emerged as a game-changing innovation. However, lead (Pb) is a toxic heavy metal, and it is crucial to explore lead-free perovskite solar cells with continuously improving efficiency for long-term development. Recently, materials researchers have discovered a lead-free double perovskite solar cell material, Cs₂InBiBr₆ with a small direct bandgap of 1.27 eV and strong thermodynamic and mechanical structural stability. The power conversion efficiency of Cs₂InBiBr₆-based perovskite solar cells is not reported yet. To investigate its potential, a solar cell capacitance simulator to analyze the solar cell structure of FTO (Fluorine Doped Tin Oxide)/ETL (Electron Transport Layer)/Cs₂InBiBr₆/HTL (Hole Transport Layer)/Au, selecting appropriate hole transport materials and electron transmission materials to achieve high efficiency is used. Moreover, this study explores the impact of several factors, including absorber layer thickness, acceptor and donor doping density, and the influence of total defect density of the perovskite and interface layers on the performance of solar cells. Advanced device characterization methods such as Mott-Schottky analysis are performed to unravel the effect of interfaces on the device performance. The solar cell with the device structure FTO/TiO₂/Cs₂InBiBr₆/Cu₂O/Au achieves an outstanding PCE of 23.64% demonstrating the immense potential of Cs₂InBiBr₆ as a lead-free double perovskite solar cell absorber layer.