Deep Insights into the Coupled Optoelectronic and Photovoltaic Analysis of Lead-Free CsSnI3 Perovskite-Based Solar Cell Using DFT Calculations and SCAPS-1D Simulations

CsSnI3 is considered to be a viable alternativeto lead(Pb)-based perovskite solar cells (PSCs) due to its suitable optoelectronicproperties. The photovoltaic (PV) potential of CsSnI3 hasnot yet been fully explored due to its inherent difficulties in realizingdefect-free device construction owing to the nonoptimized alignmentof the electron transport layer (ETL), hole transport layer (HTL),efficient device architecture, and stability issues. In this work,initially, the structural, optical, and electronic properties of theCsSnI(3) perovskite absorber layer were evaluated using theCASTEP program within the framework of the density functional theory(DFT) approach. The band structure analysis revealed that CsSnI3 is a direct band gap semiconductor with a band gap of 0.95eV, whose band edges are dominated by Sn 5s/5p electrons After performingthe DFT analysis, we investigated the PV performance of a varietyof CsSnI3-based solar cell configurations utilizing a one-dimensionalsolar cell capacitance simulator (SCAPS-1D) with different competentETLs such as IGZO, WS2, CeO2, TiO2, ZnO, PCBM, and C-60. Simulation results revealed thatthe device architecture comprising ITO/ETL/CsSnI3/CuI/Auexhibited better photoconversion efficiency among more than 70 differentconfigurations. The effect of the variation in the absorber, ETL,and HTL thickness on PV performance was analyzed for the above-mentionedconfiguration thoroughly. Additionally, the impact of series and shuntresistance, operating temperature, capacitance, Mott-Schottky,generation, and recombination rate on the six superior configurationswere evaluated. The J-V characteristicsand the quantum efficiency plots for these devices are systematicallyinvestigated for in-depth analysis. Consequently, this extensive simulationwith validation results established the true potential of CsSnI3 absorber with suitable ETLs including ZnO, IGZO, WS2, PCBM, CeO2, and C-60 ETLs and CuI as HTL,paving a constructive research path for the photovoltaic industryto fabricate cost-effective, high-efficiency, and nontoxic CsSnI3 PSCs.