A comprehensive study on Sr_xCa_1-xTiO₃ perovskites using DFT and experimental approach for thermoelectric and optical applications

The current work explores various parameters of Sr_xCa_1-xTiO₃ perovskites for advanced optical and thermoelectric applications. These compositions were simulated using a density functional approach prior to experimental observations to predict different properties, focusing on optical and thermoelectric responses. The uniform and phase-pure crystalline compositions were fabricated for experimental outcomes. The crystallographic and compositional information revealed a cubic crystal structure without the presence of any other element or impurity phase. The pristine calcium titanate exhibited a uniform rod-like morphology, which was tactically altered upon Sr incorporation into the structure, with increased length and thickness of rods. A notable contribution of Ca-d, Ti-d, O-p, and Sr-d orbitals was observed by density of states analysis. The Sr content effectively modified the CaTiO₃ thermoelectric features by tuning the Seebeck coefficient and power factor. The highly Sr-containing composition showed the maximum epsilon, reflectivity, and refractive index as ≈3.65, ≈150, and ≈2.47, respectively, in experimentally evaluated parameters. Surprisingly, the measured CaTiO₃ band gap remarkably reduced from 2.90 eV to 1.60 eV upon Sr incorporation. Various enhanced parameters of Sr_xCa_1-xTiO₃ perovskites are signifying their effectiveness for future optical and electronic devices.