Investigation of novel all-inorganic perovskites Ba₃PX₃ (X = F, Cl, Br, I) with efficiency above 29%

Lead-free inorganic halide perovskites, specifically Ba₃PX₃ (X = Cl, F, I, Br) have gained attention in green photovoltaics due to their remarkable mechanical, optical, structural, and electronic properties. Using first-principles calculations, we investigated the mechanical, electronic, and optical characteristics of Ba₃PX₃, revealing direct band gaps at the <i>Γ</i>-symmetry point, assessed with the PBE and HSE functionals. The charge distribution analysis shows strong ionic bonding between Ba and halides and covalent bonding between P and halides. The perovskites exhibit desirable optical properties, including high absorption in the visible-UV range, making them ideal for optoelectronic devices. Furthermore, SCAPS-1D simulations on Ba₃PF₃, Ba₃PCl₃, Ba₃PBr₃, and Ba₃PI₃-based solar cells with the SnS₂ ETL layer revealed power conversion efficiencies of 23.15%, 16.13%, 21.63%, and 29.89%, respectively. Consequently, the Ba₃PI₃ compound shows significant potential as an absorber in solar cells based on the SnS₂ ETL layer in the near future.