Computational investigations of optoelectronic properties of K2ScAuX6 (X = Cl, Br) double perovskites for energy harvesting devices

[Display omitted] •Halide based double perovskites K2ScAuX6 (X = Br, I) have been theoretically investigated using WEIN2k software.•Structural parameters were optimized using Perdew–Burke–Ernzerhof generized gradient approximation (PBEsol-GGA)•Investgation of mechanical response of these materials revealed their ductile nature.•Indirect band gap nature with bang gap values of 2.20 eV and 1.90 eV were estimated using mBJ potential.•Electronic transport properties in a wide range of temperature has been evaluated. Here we report a theoretical analysis of various technologically important physical properties of double perovskites K2ScAuX6 (X = Cl, Br) including thansport, optoelecronic, and strucutral. The computation of tolerance factor and estimation of entahly of formation remained key indicators to ensure the srucutal and thermodynamic stability of these compositions. The substitution of Br at Cl site increased the lattice parameter and reduced the bulk modulus. The computation of elastic constants-based modulus of elasticity revealed their ductile nature. The analysis of electronic band structure unveiled their indirect bandgap nature. Polarizability of material is accessed by computing the dielectric constant, scattering by extinction coefficient, absorption by refractive index, in addition to electrical and thermal conductivity and the Seebeck coefficient, highlighted their suitability for advanced technologically important applications in optoelectronic and thermoelectric industry.