Investigating the physical characteristics of inorganic cubic perovskite CsZnX₃ (X = F, Cl, Br, and I): An extensive ab initio study towards potential applications in photovoltaic perovskite devices

CsZnX₃ (X = F, Cl, Br, I) cubic perovskite compounds were investigated using Wien2K with PBE and mBJ energy exchange potentials to determine their structural, electronic, optical, thermoelectric, and thermodynamic properties. The results of Phonon vibrational frequency, formation energy, and cohesive energy show that all compounds are stable. The electronic properties revealed that CsZnF₃ has the highest indirect bandgap as an insulator, followed by CsZnCl₃ and CsZnBr₃, and CsZnI₃ has the lowest indirect bandgap. CsZnX₃ (X = Cl, Br, I) are classified as p-type semiconductors based on their electronic structure and the positive values of the Seebeck coefficient. High transparency was shown by low visible and infrared absorption. The investigated compounds exhibit high power factor and high figure of merit (ZT), which exceeds 0.7 over the temperature range 300–800 K. As the material's temperature rises, its lattice heat conductivity decreases in accordance with thermodynamics. However, when the temperature exceeds the Debye temperature, the volume heat capacity matches the Dulong-Petit limits and the experimental results.