Synergistic approach using DFT insights and SCAPS-1D simulations to unlock the photovoltaic potential of Cs2SnBr6-Based solar cell

초록

Lead-free double perovskites receive extensive research attention due to their appropriate bandgap and high absorption coefficient, which are essential for photovoltaic applications. The present communication employs a first-principles approach to explore the structural, mechanical, electronic, and optical characteristics of Cs2SnBr6, demonstrating the cubic symmetry with a lattice constant of 10.909 & Aring;, a tolerance factor of 1.02, and an enthalpy of formation of-3.18 eV, confirming its structural and thermodynamic stability. The computed elastic constants satisfy the Born stability criteria, revealing its mechanical stability. The electronic band structure analysis exhibits a direct bandgap of about 1.44 eV, a static refractive index of 1.91, and a high absorption coefficient of 5.7 x 105 cm-1, thereby positioning it as an excellent candidate for solar energy harvesting. Further, to achieve optimal device performance, 50 combinations with 10-hole transport layers (CZTSe, CdTe, Sb2S3, V2O5, CNTs, MoS2, Cu2Te, Zn3P2, NiO, CuI) and 5 electron transport layers (WS2, TiO2, IGZO, SnO2, CdZnS) are systematically investigated using SCAPS-1D software, where the FTO/TiO2/Cs2SnBr6/Zn3P2/Au configuration establishes superior photovoltaic performance. The thickness, defect, and doping concentrations of the absorber layer are systematically optimized to investigate the effects of these parameters on charge generation, carrier recombination, and quantum efficiency. The optimized FTO/TiO2/Cs2SnBr6/Zn3P2/Au device exhibited a Vocof 1.08 V, Jscof 29.92 mA/cm2, FF of 84.92%, and a PCE of 27.51% at an absorber thickness of 1000 nm, defect density of 1 x 1014 cm-3, doping concentration of 1 x 1016 cm-3, operating temperature of 300 K, series resistance of 1 Omega cm2, and shunt resistance of 1 & times; 105 Omega cm2. These findings underscore the potential of FTO/TiO2/Cs2SnBr6/Zn3P2/Au as a highly stable, lead-free alternative for next-generation PSCs, offering both environmental sustainability and promising efficiency.

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