Enhancing Efficiency in Lead-Free Perovskite Solar Cells: The Role of Interface Defect Density in FAMASnGeI₃ Device

This work investigates effects of defects present at the interface at the performance of a perovskite solar cell (PSC) with the composition "PCBM/FAMASnGeI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>/CuI". Made of formamidinium (FA), methylammonium (MA), tin (Sn), and germanium (Ge), FAMASnGeI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> is a lead-free perovskite material. It is the active layer in charge generation and light absorption. Typical lead-based perovskites have environmental and toxicological issues, hence the use of this substance is meant to address such issues. On the other hand, a high defect density at the interfaces between the ETL (PCBM), the perovskite layer (FAMASnGeI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>), and the HTL (CuI) results in an increase in charge recombination, which in turn reduces significant photovoltaic parameters including V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OC</inf>, J<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</inf>, FF, and PCE. By means of material engineering and passivation, It has been able to reduce these defects, therefore enabling us to show improvements in device performance and hence enable the generation of additional energy. FAMASnGeI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> offers a safer and more ecologically friendly alternative to lead-based perovskites, hence its use is in line with affordable and clean energy. By means of the removal of harmful substances, its nontoxic character supports responsible Consumption and production. Furthermore related to industry, innovation, and infrastructure which promotes the development of clean energy technologies able to contribute to a more environmentally friendly global energy system is the possibility for scalable and cost-effective manufacturing of these solar cells.