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The growing material for optoelectronics, thermoelectric and renewable energy applications includes Ge1−xBixTe (x= 12% and 24%). So, by using DFT and WEIN2k code, we calculated the electronic, optical and also thermoelectric properties of Ge1−xBixTe (x= 12% and 24%). In GGA and GGA + SO, the band structures are studied which shows metallic nature. The entire geometric optimization process was carried out based on the cell parameters. Obtained results suggested that Ge1−xBixTe (x= 12% and 24%) exhibits a predominantly metallic behavior. From through study of electronic charge density, we verified that the nature of examined material is primarily metallic. Bottom of the conduction and top of valence bands are due to Bi, Ge-pand Ti-p/sorbitals with minimal contributions of Bi-s orbitals states. We estimated optical parameters like optical conductivity, absorption coefficient, dielectric function, reflectivity coefficient, loss function, and refractive index for the polarized incident radiation. Finally, we calculated thermoelectric attributes like seebeck coefficient and others with the use of Boltzmann transport theory. The calculated optical and thermoelectric properties suggested that the doped system could be a potential material for optoelectronic applications with high absorption coefficient values in visible and ultraviolet region. This research provides valuable insights into the potential use of Ge1-xBixTe for both x= 12% and 24% by using GGA + SO as promising candidate for renewable energy applications.

The development of a thin film titanium dioxide (TiO2) depends on an understanding of complex electronic structure and charge transport properties. The utilization of simulation studies will help us understand the complicated system at the atomic level. Here, utilizing Hubbard's modified first-principles density functional theory (DFT + U), a theoretically created thin film TiO2(111) interface model is provided. Generalized gradient approximation with Perdew-Burke-Ernzerhof assistance (GGA + PBE) was used to model structural properties, while Hubbard's modified (GGA + U) exchange correlation functional was used to simulate optoelectronic properties. The addition, i.e., doping and adsorption, of Fe to the TiO2rutile (111) surface transfers its bandgap energy from 2.95 eV to a metallic nature, thereby enhancing its responsiveness to visible light by lowering the energy required for electron transitions. The enhanced visible light absorption and efficient charge separation worked together to significantly improve the hybrid photo catalyst’s photocatalytic performance. The research utilized the DFT method along with the (GGA + U) technique to evaluate both the band structure and density of states (DOS). The analysis of the electronic structure shows that the band gap for the pristine but for the doped and adsorbed systems the nature of the materials changes to metallic. The DOS calculations indicate hybridization between O-orbitals and Fe-orbitals in the vicinity of the conduction band minimum for both channels due to the doped system, and for the maximum in the case of the adsorbed system, the impurity introduces an energy level that lowers the band gap. The research carried out computations to determine the band structure and density of states for (TiO2) doped with Fe and Fe-adsorbed. The results demonstrate that the doped and adsorption is considered to be a more advantageous approach than the pristine because of the maximum absorption in visible region. When the Fe atoms are adsorbed on TiO2(111), there is a maximum increase in the adsorption energy. The study examines the photo activity mechanism by investigating the impact of Fe on the semiconductor's absorption edge. This type of semiconductor, with Fe adsorbed on TiO2(111), has potential applications in the fields of photovoltaic, photocells, and electronics.