Electrifying insights: coulombic influence on optoelectronic behavior of Eu and Gd doped K₄SrSi₃O₉ investigated via first-principles calculations for solar cell innovation

Excellent thermal and chemical stability is a natural result of silicates’ rigid structural design. Due to these factors, silicate-based photonic materials have been thoroughly studied. Modern optoelectronic devices rely primarily on the optical and electrical properties of semiconductors. In this research work, using first-principles calculations within the framework of Density functional theory, we have investigated the optoelectronic properties of pristine and Eu/Gd doped K₄SrSi₃O₉. The generalized gradient approximation and Hubbard parameter were used for all these calculations. Our results revealed that the investigated material is a direct band gap material with a band gap energy of 5.209 eV. By incorporating Eu, the band gap reduces to 2.32 eV which is attributed to the induction of intermediate bands, while doping Gd into K₄SrSi₃O₉, the material becomes metallic. It was observed that all three compounds are spin-polarized. Optical properties as a function of photon energy, like dielectric function (real and imaginary), refractive index, electron energy loss spectrum, reflectivity, and absorption coefficient have been calculated. The optical properties of spin-up states are more attractive than its counterpart, which make Eu-doped K₄SrSi₃O₉ a potential candidate for optoelectronic devices.