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In this study, we used density functional theory to examine how the wide band gap optoelectronic properties of pure, silver-, and cadmium-doped LaAlO3 perovskites changed. Structural, electrical, elastic, and mechanical properties were calculated using generalized gradient approximation. Silver and cadmium incorporated at Al site demonstrated a decreasing trend in the band gap. Both impurities showed the reduction in band gap from 2.98 to 0.468 eV and from 2.98 to 2.0238 eV. The density of states was examined for pristine and doped structures to understand behavioral change of LaAlO3. It was observed that p states in upper valance band and d states in lower conduction band were contributing toward the reduction of band gap. Elastic properties were computed. Elastic parameters were used to calculate Born's stability and it is predicted that the material is stable mechanically for both pristine and doped forms. Mechanical properties were also predicted and brittle nature was found for both pristine and doped materials. Optical responses such as dielectric function, absorption, and refractive index were also predicted. The impurity inclusion in pristine structure not only reduces the bad gap but also alters the optical behavior. Absorption edge shifted toward lower energy shows a clear redshift, whereas refractive index also reduces from 2.4 to 1.9, making the material more transparent. The absorption spectrum as well as electronic band gap makes this material more useful for solar cell application as well as photocatalytic applications. [ABSTRACT FROM AUTHOR]

Due to the depletion of non-renewable fossil fuels, energy production and storage is a matter of concern for scientific community. Hydrogen being environmental friendly was presented by the scientists a fruitful replacement of fossil fuel, but the storage of hydrogen is still a matter of concern. Safety concerns are associated with hydrogen as an alternative fuel because it is difficult to store and transport. Perovskite materials have attracted researchers as new materials for solid hydrogen storage. In this present work, Density Functional Theory (DFT) calculations have been performed for perovskite NaMg F 3 − x H x with the GGA-PBE formalism as implemented in the CASTEP code. The aim of the work is to investigate the structural, electronic and optical properties of NaMg F 3 − x H x perovskite hydride material for hydrogen storage applications with varying substituent concentrations (x = 0, 0.3, 0.6, 0.9, 1.2). The formation enthalpy of the studied material for each concentration reveals that these compounds are stable and synthesizable experimentally. The hydrogen inclusion in pristine material affects the electronic states significantly which is elaborated using band structure and density of states plots. After Hydrogen inclusion, change in density of states has been observed and the band gap is decreased from 5.74 e V to 3.311 e V. The alteration of electronic band gap directly influences the optical behavior of the material, thus optical response such as dielectric function, absorption and refractive index was also calculated. For hydrogen storage application, gravimetric storage capacity (C w t %) was calculated for all concentrations of hydrogen inclusion. The value varied from 0.30% to 1.87%, indicating that the presented material is an efficient material not only for opto-electronic applications but also for the hydrogen storage applications. • DFT calculations have been performed for perovskite NaMg F 3 − x H x. • The band gap is decreased from 5.74 e V to 3.311 e V due to inclusion of H. • Optical parameters including absorption were enhanced. • The gravimetric storage capacity (C w t % ) values are varied from 0.30% to 1.87%. [ABSTRACT FROM AUTHOR]

This study explores the optoelectronic potential of advanced perovskite materials, with a primary focus on alloying KMgF 3 with 3d transition metals. Through this alloying process, the study employs density functional theory (DFT) with the GGA-PBE functional to tailor the atomic structure and various properties, including optoelectronic, mechanical, acoustic, anisotropic, and photocatalytic attributes. The introduction of Zn to KMgF 3 triggers a noticeable bandgap redshift and significant improvements in mechanical stability and photocatalytic performance. Increasing Zn content induces a transition in KMgF 3 's crystal structure to a pseudo-cubic tetragonal form, which remains mechanically stable for both pristine KMgF 3 and KMg (1-x) Zn x F 3. Zn inclusion introduces versatile nonlinearity in terms of brittleness, stiffness, mechanical strength, and thermal behavior. This comprehensive analysis underscores anisotropy, mixed bonding, Debye fluctuations, and melting temperature variations. Notably, among the systems examined, KMg 0.25 Zn 0.75 F 3 stands out as an outstanding candidate for applications in photovoltaics and water splitting, thanks to its exceptional optical performance. • Mechanical properties of pristine and Zn doped KMgF 3 are investigated. • Results indicated that KMg (1-x) Zn x F 3 can exist in layered configuration. • 3d TM inclusion in KMgF 3 tuned the electronic band gap while preserving its indirect nature. • Photocatalytic Performance improved upon doping due to band gap reduction. [ABSTRACT FROM AUTHOR]

The structural, mechanical, and opto-electronic properties of cubic RbCdF 3 (c-RCF) under high pressures were probed using a Generalized-Gradient Approximation (GGA-PBE) within the fram work of CASTEP. The aim of this study is to see how pressure affects structural and electronic properties and in response of electronic change how optical behaviour altered along with mechanical properties. The calculated structural properties such as the equilibrium lattice parameter (4.59 Å), the bulk modulus (63.7821) and its pressure derivative are in good agreement with the available data at pressure 0 GPa. The obtained results for the band structure and the total density of states (TDOS) show that the RbCdF 3 has an indirect band gap of 2.863 eV. The changing electronic properties affect optical response which was studied and discussed. The refractive index (n(ω)) decreases from 2.6 to 1.72 gradually with increasing pressure. The elastic constants were calculated using the energy deformation relationship, from these constants the other mechanical properties such as bulk modulus, shear modulus, Young modulus and Poisson ratio were calculated and commented. The results of elastic constants established that RbCdF 3 is mechanically stable at each pressure because it fulfills the Born's stability criteria. RbCdF 3 behaves as brittle at low pressure when we increased pressure it shows ductile nature in this study. Poisson ratio (σ) and Cauchy pressure also confirm similar behaviour. Lastly, the anisotropy factor was discussed. RCF is thus a fascinating material for optoelectronic devices, thermoelectric and piezoelectric properties. • The structural, mechanical, and opto-electronic properties of cubic RbCdF 3 (c-RCF) under high pressures were probed. • The calculated structural properties such as the equilibrium lattice parameter (4.59 Å), the bulk modulus (63.7821) and its pressure derivative are in good agreement with the available data. • The RbCdF 3 has an indirect band gap of 2.863 eV. • The refractive index (n(ω)) decreases from 2.6 to 1.72 gradually with increasing pressure. • The results of elastic constants established that RbCdF 3 is mechanically stable at each pressure. [ABSTRACT FROM AUTHOR]