Investigations of optoelectronic, magnetic, and transport properties of Zintl-phosphides BaX₂P₂ (X=Cd, Sn, Cu) for green technology: First principle calculations

One way to decarbonize the world's energy generation is through thin-film photovoltaics (PV), there are significant problems with elemental abundance, stability, or performance with the thin-film solar absorbers that are now on the market. We present the optoelectronic and transport properties of Zintl-phosphides BaX₂P₂ (X = Cd, Sn, Cu) using first-principles calculations based on density functional theory. Our calculations show that increasing the band gap of Cd/Sn and Cu-based phosphides from 0.5 to 4.0 eV enables fine adjustment of bandgaps, structure, and optoelectronics, broadening the material's potential applications in the semiconducting industry. Strong absorption occurs in the energy range of 4–8 eV; it concluded that their optical characteristics, such as natural and imaginary dielectric functions, refractive index, and absorption coefficient, might make them useful in optoelectronic and photovoltaic applications. In the 50–800 K temperature range, power factor (PF), electrical conductivity, thermal conductivity, and Seebeck coefficient were investigated. With PFs of approximately 7.5 × 10¹⁰ W/K²ms, respectively, the compound demonstrated a considerable potential utility in thermoelectric devices. An assessment of radiation shielding performance was conducted using the XCOM tool across a broad energy range ranging from 15 keV to 15 MeV. The findings indicated that the mass attenuation coefficient (G_MAC) values increased proportionately of BaCd₂P₂, BaSn₂P₂, and BaCu₂P₂ samples. The G_MAC peaked for all sample compositions at around 0.015 MeV, with values spanning from 42.94 cm²/g for BaCd₂P₂ to 51.96 cm²/g for BaCu₂P₂. Nevertheless, when elevating the energy level beyond 15 keV, a notable decline in G_MAC values was observed. This is likely mostly attributable to the predominance of photoelectric interactions at lower energy levels. These compounds' strong absorption patterns and high PF make them promising materials for thermoelectric and photovoltaic applications.