Analysis of XGaO3 (X = Ba and Cs) cubic based perovskite materials for photocatalytic water splitting applications: a DFT study

Computational insights of double perovskite Na2CaCdH6 hydride alloy for hydrogen storage applications: a DFT investigation

Prospective use of perovskite hydride materials in H storage a crucial element of clean energy systems has drawn a lot of attention. The structural, electrical, mechanical, thermodynamic, and H storage qualities of Na2CaCdH6 hydride alloys were examined in this work using DFT. According to the structural properties, Na2CaCdH6 has space group 225 (Fm3m), and optimized lattice parameters and volume of Na2CaCdH6 are 3.3485 Å and 593.764 Å3. The measured gravimetric H storage capacity of Na2CaCdH6 hydrides is 2.956 wt%. The hydrides under research are semiconductors, as indicated by the computed electronic characteristics. Elastic constants, Pugh's ratio, modulus, Poisson's ratio, anisotropic, and microhardness of Na2CaCdH6 are calculated under mechanical properties. The hydrides are dynamically stable, as indicated by the phonon dispersion curves, but mechanically stable according to the Born criterion for elastic constant (Cij). The Cauchy's pressure (C″ = 7.836) revealed the ductile behavior. The electronic and mechanical characteristics imply that Na2CaCdH6 hydride can conduct electricity and is also mechanically stable. Our findings shed light on the possibilities of Na2CaCdH6 perovskite hydride material for H storage utilization.

Computational investigation on physical properties of lead based perovskite RPbBr3 (R = Cs, Hg, and Ga) materials for photovoltaic applications

In the modern era, the major problem is solving energy production and consumption. For this purpose, perovskite materials meet these issues and fulfill energy production at a low cost. Density functional theory and the Cambridge Serial Total Energy Package (CASTEP) are used to examine the characteristics of the cubic inorganic perovskites RPbBr3 (R = Cs, Hg, and Ga). In the context of the generalized gradient approximation (GGA), the ultrasoft pseudo-potential plane wave technique and the Perdew-Burke-Ernzerhof exchange-correlation functional are used for investigations. Structural, mechanical, electronics, and optical properties are investigated using CASTEP code. According to structural properties, compounds have a cubic nature with space 221 (Pm3m). Compounds formation energy (- 3.46, - 2.21, and - 3.14 eV)of (CsPbBr3, HgPbBr3, and GaPbBr3) and phonon calculations are studied and find that compounds are stable. The results of our investigation show that the compounds have narrow bandgaps of direct kind, with 1.85 eV for CsPbBr3, 1.56 eV for HgPbBr3, and 1.71 eV for GaPbBr3, respectively, indicating that they may be used to improve conductivity. Additionally, anisotropy (2.135, 3.651, 10.602), Pugh's ratio (1.87, 2.25, 2.14), and Poison's ratio (0.27, 0.31, 0.29) are traits that the compounds (CsPbBr3, HgPbBr3, GaPbBr3) display a ductile nature. The CsPbBr3 compound showed significant optical conductivity and absorption in terms of their optical properties, especially in the visible region, which makes them suitable for use in solar cell applications as well as for LED applications.

Investigation of ultra wide bandgap Flouro-perovskite materials RBeF3 (R[bond, double bond]K and Li) for smart window applications: A DFT study

The human body is affected by ultraviolet radiation because it can penetrate and harm bodily cells. Although skin cancer and early aging are consequences of prolonged exposure to ultraviolet (UV) rays, sun rays signify immediate excessive exposure. In this context, some structural, optical, electrical, and mechanical properties of the beryllium-based cubic fluoro-perovskite RBeF3 (R[bond, double bond]K and Li) compounds are examined through the use of density functional theory (DFT) within generalized gradient approximation (GGA) using the Perdew-Burke-Ernzerhof (PBE) approximations (GGA-PBE). The compounds KBeF3 and LiBeF3 have space group 221-pm3m, and their lattice constants and volumes are (3.765, 3.566) Å and (53.380, 45.379) Å3, respectively, based on their structural properties. Computed results indicate that the compounds' bandgaps are 7.35 eV and 7.12 eV, respectively, with an indirect nature for KBeF3 and LiBeF3. The properties of the band structure indicate that both compounds are insulators. The bonding properties of these compounds, RBeF3, are a combination of covalent and ionic. Optical properties of the compounds are examined which reflect the light-matter interaction like reflectivity, conductivity, and absorption. These materials were likely very hard but brittle, based on a higher bulk modulus B from elastic features, the B/G ratio, Pugh's ratio, and Vickers hardness. The compound RBeF3, as determined by the findings, is used as a UV protection and reflection layer for car and room windows.

Pressure-driven modification of optoelectronic features of ACaCl3 (A = Cs, Tl) for device applications

Intending to advance the use of halide-perovskites in technological applications, in this research, we investigate the structural, electronic, optical, and mechanical behavior of metal-halide perovskites ACaCl3 (A = Cs, Tl) through first-principle analysis and assess their potential applications. Due to the applied hydrostatic pressure, the interaction between constituent atoms increases, thereby causing the lattice parameter to decrease. The band structure reveals that band gap nature transits from indirect to direct at elevated pressure. Moreover, at high pressure, the electronic band structure shows a notable band gap contraction from the insulator (>5.0 eV) to the semiconductor region, which makes them promising for electronic applications. The charge density map explores the ionic and covalent characteristics of Cs/Tl-Cl and Ca-Cl under pressured and unpressurized environments. Induced pressure enhances the optical conductivity as well as the optical absorption that moves toward the low-energy region (red shift), making ACaCl3 (A = Cs, Tl) advantageous for optoelectronic applications. Additionally, this study reveals that the mechanical properties of ductility and anisotropy were found to be improved at higher pressures than in ambient conditions. Overall, this study will shed light on the technological applications of lead-free halide perovskites in extreme pressure conditions.

Investigation of structural, electronic, mechanical, & optical characteristics of Ra based-cubic hydrides RbRaX3 (X= F and cl) perovskite materials for solar cell applications: First principle study

Perovskite materials are considered the gateway of various physical applications to meet the production and consumption of energy and medical fields. Density Functional Theory (DFT) becomes the most important field in the modern era to investigate perovskite materials for various physical properties. DFT nowadays is used to explore the perovskite materials for a lot of applications like photocatalytic, optoelectronic, and photovoltaics. We discussed radium based cubic hydrides RbRaX3 (while X = F & Cl) perovskite material's electrical, optical, elastic, & physical characteristics with the help of DFT-based CASTEP code with PBE exchange-correlation efficient of GGA. The RbRaF3 & RbRaCl3 have three-dimensional nature by means of space group 221 (Pm3 m). According to electronic characteristics, the direct bandgap of RbRaF3 RbRaCl3 are 3.18eV and 2.209eV, respectively. Both compounds are brittle in nature via Poisson's ratio & Pugh's criteria. Thus, our novel RbRaX3 (X = F and Cl) compounds have excellent applications for solar cell and medical areas.

First principles calculation to investigate the effect of Mn substitution on Cu site in CeCu3-x Mn x V4O12 (x = 0, 1, 2 and 3) system

Structural, electronic, elastic and magnetic properties of CeCu3-x Mn x V4O12 (x = 0, 1, 2 and 3) system have been carried out through DFT using GGA, GGA+U and HF potential. The investigation of structural optimization reveals that lattice parameters of the understudy system is reliable with the reported results and are increasing with the Mn substitution due to their greater atomic radii as compare to Cu atom. Both the cohesive energy and the enthalpy show that CeCu3V4O12 is the most thermodynamically stable among these compounds. When Mn is replaced by Cu in these compounds, not only it become semi-metals, but the host compound also changes from non-magnetic to anti-ferromagnetic and their electrical resistance provides further credence to their electronic behavior. Mechanical stability, anisotropy, and ductility are all demonstrated through the elastic characteristics of these compounds. Due to anti-ferromagnetic ductile nature of the Mn base compounds, it is expected that the compounds in the system may use for spintronic application and in magnetic cloaking devices.