DFT-Based Investigation of Opto-Electronic, Mechanical, and Thermoelectric Properties of Sr2YBiO6 for Green Energy Applications

The present study on double perovskite Sr2YBiO6 has used a full potential linearized augmented plane wave (FP-LAPW) approach in conjunction with density functional theory (DFT) and semiclassical Boltzmann theory. The study has used PBE-GGA, PBE-sol, mBJ, mBJ + SOC exchange potentials to obtain clear electronic structure of the material. The electronic structure analysis indicates that Sr2YBiO6 compound exhibits semiconductor behavior with an indirect energy gap of 2.150 eV, using TB-mBJ. Further, material is mechanically and thermodynamically stable. The no negative frequencies in the phonon spectra confirm dynamical stability as well. This study investigates optical properties of Sr2YBiO6, including dielectric function, refractive index, electrical conductivity, absorption, reflectivity and electron loss function. We report static optical reflectivity 0.085, which expresses, 8.5% of incident light is reflected rest is absorbed. A static refractive index is estimated to be 1.82, suggests that Sr2YBiO6 has moderate optical density and transparency in the long-wavelength range, which is useful in designing optical and photonic devices. Further, on the ground of thermoelectric performances, the values for Seebeck coefficient, power factor and figure of merit are estimated to be 214.8 mu V/K, 7.34 1011W/K2ms and 0.062 at 300 K, respectively. The value of figure of merit increases to 0.7 at high temperature of 1200 K. Thermodynamic behavior and elastic properties have also been investigated for this compound. Our computed results are in accordance with the other double perovskites. The findings demonstrate that this double perovskite material is outstanding for both UV and visible-light photovoltaic applications, as well as for thermoelectric devices.