ETL engineering in lead-free new Ca3PBr3 perovskite type structure of anti-perovskite derivative material for stable and effective photovoltaic solar cells

Abstract

This study explores the structural, electronic, mechanical, optical, and photovoltaic properties of the Ca₃PBr₃ anti-perovskite derivative material using DFT and SCAPS-1D simulations. The results confirm its high stability through tolerance factor and phonon dispersion analysis, further supported by mechanical stability studies. Bandgap calculations reveal a direct bandgap of 1.65 eV (PBE) and 2.63 eV (HSE) at the Γ-point, indicating semiconducting behavior. Optical analysis highlights strong absorption in the visible to ultraviolet range, as shown by its dielectric functions, absorption coefficients, and conductivity. SCAPS-1D modeling assessed solar cell performance with ETLs such as WS₂, CdS, TiO₂, and ZnS, optimizing parameters like absorber thickness, acceptor density, defect density, QE, and J–V characteristics. Under optimal conditions, FTO/ETL (WS₂, CdS, TiO₂, ZnS)/Ca₃PBr₃/Au devices achieved efficiencies of 19.39%, 18.69%, 17.21%, and 17.46%, respectively. The study highlights WS₂ as a promising ETL for designing efficient and durable Ca₃PBr₃-based solar cells.