Modeling of Lead-Free CH₃NH₃SnI₃-Based Perovskite Solar Cell Using ZnO as ETL

Abstract

Over the last few decades, researchers have invested enormous research effort into inorganic/organic solar cells like dye-sensitized solar cells (DSSCs) due to its cost-effectiveness and simple fabrication process, over the conventional photovoltaic solar cells made of different materials like Si, Ge, GaAs, GaInPh. In 2012, the solid-state perovskite materials are organic–inorganic metal trihalide materials, having chemical formula ABX3 and having specific crystal structure as calcium titanium oxide (CaTiO₃) revolutionized as the light-harvesting, absorbing materials. In past couple of years, perovskite solar cells have shown significant improvement in terms of efficiency and crossed the 20% efficiency level. There has been a consistent approach among researchers to explore different materials as electron transport layer of the perovskite solar cells to improve the performance of the solar cells. The most common perovskite material used in solar cell is methyl ammonium lead iodide (CH₃NH₃PbI₃) along with top and bottom layer of HTO and ETO. In this work, the toxic material lead iodide (PbI₃) is replaced with tin oxide (SnI₃), and this perovskite material CH₃NH₃SnI₃ introduced with an ETO layer of ZnO has achieved a significant efficiency of 22.90%. In this work, zinc oxide (ZnO) layer is proposed as the electron transport layer for lead-free CH₃NH₃SnI₃-based perovskite solar cells. The proposed structure is “metal contact/spiro-MeOTAD/CH₃NH₃SnI₃/ZnO/TCO/metal contact,” and the structure is modeled using SCAPS simulating tool.