DFT Insight Into Physical Properties of Halide Ions Replacements in Oxo‐Selenate Halide Compounds for Photovoltaic Application

ABSTRACT A comprehensive DFT‐based analysis has been performed for oxo‐selenate halide YSeO 3 X (X = F, Cl, Br, and I) compounds by using the GGA‐PBE functional approach under the framework of the CASTEP code. With the absence of any imaginary frequencies in the phonon dispersion curves, the dynamic stability of structures is reported, and for mechanical stability Born stability criterion is employed. Electronic properties demonstrate that all the compounds under observations possess wide band gaps except YSeO 3 I, and due to its lower value of band gap (1.04 eV) it shows high value of optical absorption (242745 cm −1 ) and optical conductivity (8.24 fs −1 ) revealing stronger optical activity in the visible and near UV regions of incident light. Thermodynamic properties have shown thermodynamic stability, which confirms the suitability of these compounds for high‐temperature optoelectronic and energy‐related applications. The convergence for heat capacity and Debye temperature exhibits that lattice vibrations and thermal resistance are present at higher temperatures, and all compounds have attained saturation closer to their Dulong‐Petit limit (74.9 cal/cell.K). Mechanical anisotropy and ductility for all compounds are also observed by mechanical properties analyses. All these outcomes suggest that these compounds possess potential for photovoltaic technologies and flexible photonic devices.