Comparative Study of the Correlation between Diffusion Length of Charge Carriers and the Performance of CsSnGeI3 Perovskite Solar Cells

Due to their enhanced performance and simplicity in manufacturing, scalability, and versatility, lead-halide perovskite-based solar cells (HPSCs) have received much attention in the domains of energy. Lead is present in nature as a poisonous substance that causes various issues to climate and human health and prevents its further industrialization. Over the past few years, there has been a noticeable interest in exploring some alternative lead-free perovskites. However, owing to some intrinsic losses, the performance that may be achieved from these photovoltaics is not up to standards. Thus, for the purpose of efficiency improvement, a comprehensive simulation is required to comprehend the cause of these losses. In the current research, an investigation into how to employ the promisingly efficient lead-free, all-inorganic cesium tin–germanium iodide (CsSnGeI3) perovskites as the photoactive layer in HPSCs was performed. Results exhibited a high efficiency of 12.95% with a CsSn0.5Ge0.5I3 perovskite thickness of 0.6 μm and a band gap of 1.5 eV at room temperature. High efficiency may be achieved using phenyl-C61-butyric acid methyl ester (PCBM) as an electron transport material because of its favorable energy-level alignment with the perovskite material. The research further tested the perovskite layer thickness and defect density in depth. The results showed that the carrier diffusion lengths have a big effect on how well the HPSC works.