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Our investigation focused on an in-depth examination of the physical properties of KZnH3 and NaZnH3, with lattice parameters of 4.04 and 3.72 Å, respectively. Both compounds exist stably in a cubic structure and exhibit metallic behavior with no band gap. At the Fermi level, the total and partial densities of states exhibit a significant conductivity, confirming the metallic behavior. These materials have brittle and anisotropic properties. Because of their greater bulk modulus, average shear modulus, and Young's modulus, NaZnH3 appears harder compared to KZnH3. Optical properties indicate significant absorption and optical conductivity in the energy spectrum of 6–9 eV. NaZnH3 has a greater static refractive index and reflectivity as compared to KZnH3. The research on hydrogen storage suggests that both of these materials can store hydrogen, however, NaZnH3 is a more promising candidate due to its higher hydrogen storage capability. [ABSTRACT FROM AUTHOR]

Effect of functional on structural, elastic, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X = Lu, Y) spinels has been realized by WIEN2k code. The lattice constant of MgY2Se4 is slightly greater than that of MgLu2Se4, and these quantities are slightly deviated from the experimental values, where the error does not exceed 1.3%. The cohesive energy proves that both spinels are chemically stable in the normal case, and this stability is more pronounced in MgLu2Y4. The large ionic radius of Lu compared to Y explains the high bulk modulus of MgY2Se4 as well as its hardness. The spinels under study have Г → Г direct band gap located between 1.178 and 1.4 eV for all the functionals, proving their semiconductor nature. Se-s, Y-d, Lu-d states in MgY2Se4 and MgLu2Se4 dominate the upper valence band, while the first conduction band located between Fermi level and 1.5 eV is empty. There is a strong coupling between Se-p–Lu-p sites for MgLu2Se4 and Se-p–Y-p states in MgY2Se4, which reflects their hybridization. The high absorption in the ultraviolet range, the band gap between 1 and 2.4 eV and the refractive index in the range of 2.29–2.61 favour these spinels as absorbers in solar cells. Peaks of all the optical quantities studied relating to the mBJ–GGA functional are shifted to the right compared with GGA and GGA+SO approximations. The thermoelectric parameters were investigated as a function of photon energy and temperature using GGA+SO functional. [ABSTRACT FROM AUTHOR]

This manuscript reports the computational study of three new perovskite-type hydrides for solid-state hydrogen storage technology. Herein, Density Functional Theory (DFT) has been implemented within CASTEP code to probe the structural, electronic, mechanical, optical and hydrogen storage properties of MgXH 3 (X = Al, Sc and Zr). Thermodynamic stability assessments reveal that all materials exhibit negative formation energy (Δ E f), guaranteeing their energetic stability and suitability for experimental synthesis. Band structure and density of states plots highlight metallic properties in MgXH 3 hydrides. The mechanical stability of these perovskites was ensured by the compliance of their elastic constants with Born's stability criteria. Bulk modulus, shear modulus, Poisson's ratio, Cauchy pressure, etc. are also processed from elastic constants. Pugh coefficient and Cauchy pressure unveil ductile behavior in MgAlH 3 and MgZrH 3 , and brittleness in MgScH 3. Optical properties revealed that MgXH 3 compounds have maximum absorption and conductivity in the ultraviolet region. The gravimetric hydrogen storage capacities were theoretically determined as 5.274, 4.015, and 2.487 wt%, for MgAlH 3 , MgScH 3 , and MgZrH 3 respectively. This research work suggests that MgXH 3 (X = Al, Sc and Zr) can be used as promising materials for hydrogen storage applications. • Three novel perovskite hydrides are examined for hydrogen storage using DFT. • MgXH 3 (X = Al, Sc and Zr) hydrides are mechanically and thermodynamically stable. • MgXH 3 perovskites are metallic in nature. [ABSTRACT FROM AUTHOR]

The present work reports a comparative study on CuO and 3.0% Mn-doped CuO nanofibers (NFs) produced by the electrospinning method. State-of-the-art characterization techniques such as Electron Energy Loss Spectroscopy (EELS) and X-Ray photoelectron Spectroscopy (XPS) have been employed to determine the multivalent states and elucidate their electronic structure at the Cu-L3,2 (2p) edge. The CASTEP code has been used to model CuO (P1) and Mn-doped (C 2/c) with the GGA-PBE functional on the supercomputing system with the Xeon10 module (10 nuclei). Structural characterization was done by using a CM 200 Philips Transmission Electron Microscope (TEM) and the chemical state of surfaces with ESCALAB 250Xi XPS Thermoscientific TM. The NFs present an indirect energy bandgap, Eg = 2.03 eV and 2.85 eV, respectively. The results show that the Cu-L3,2 edge presents degenerate states associated with Cu 2p - O and Cu 3d - O hybridization, indicated as Cu3+.

Structural, elastic, mechanical and electronic properties of pure and zinc-doped SrTiO3 at the concentration in the range (1–10%) are studied by first-principles calculations. The structural parameters of synthesized compounds agree well with the standard data depicting the growth of stable compounds. A slight obvious increase in the lattice constant of 3.9245 Å is observed in Zn-doped SrTiO3 due to the deviation of the atomic radii of Zn and Ti. Elastic constants and mechanical parameters of SrTiO3 are closer to their available theoretical and experimental data. The investigated compounds exhibit brittle behavior for all Zn ratios. The doping zinc concentration reduces the indirect band gap value. The doping concentration 2%, gives a band gap value closer to the experimental one. The band gap of pure SrTiO3 is 1.827 eV and after doping with Zn for concentration from 1% to 10%, the optimized values are 1.970, 1.886, 1.802, 1.718, 1.635, 1.552, 1.470, 1.389, 1.310, 1.231 and 1.154 eV. [ABSTRACT FROM AUTHOR]

This work presents a Density Functional Theory (DFT) study of the single perovskite CsXH 3 (X = Co, Zn). We used the CASTEP code to perform first-principles calculations and investigate the hydrogen storage properties of CsXH 3 (X = Co, Zn). We calculated the structural, Hydrogen, mechanical, electronic, optical, and thermal properties of CsXH 3 (X = Co, Zn) perovskite materials for hydrogen storage applications. Electronic properties reveal that CsXH 3 (X = Co, Zn) has a metallic behavior. The calculated value of formation energy is −0.47 eV/atom and −0.18 eV/atom for CsCoH 3 and CsZnH 3 , respectively, which means that the studied materials are synthesizable and thermodynamically stable. Our results show that CsXH 3 (X = Co, Zn) is a promising material for hydrogen storage, as it exhibits high hydrogen storage capacity. The gravimetric ratio values are 2.82 wt% and 3.09 wt% for CsCoH 3 and CsZnH 3 , respectively. The determined elastic constants show that CsXH 3 (X = Co, Zn) is mechanically stable. Our study provides valuable insights into using single perovskite CsXH 3 (X = Co, Zn) as a potential material for hydrogen storage applications. • Performance of DFT study for CsXH 3 (X = Co, Zn) perovskites materials for hydrogen storage applications. • The elastic constants values show that CsXH 3 (X = Co, Zn) is mechanically stable. • Calculated formation energy is −0.47 and −0.18 for CsCoH 3 and CsZnH 3 respectively. • The studied materials are synthesizable, thermodynamically stable and are most suitable for hydrogen storage applications. [ABSTRACT FROM AUTHOR]

Two-dimensional perovskite materials have recently attracted significant interest in solar cell applications. This study employed DFT calculations to investigate the structural, electronic, optical, magnetic, thermal properties and spectroscopic limited maximum efficiency (SLME) of Cs 3 Sb 2 X 9 (X = Cl, Br) perovskites. The dynamic vibrational stability was calculated using the phonon energy dispersion curve; results show that Cs 3 Sb 2 X 9 (X = Cl, Br) is dynamically stable. The electronic band structure revealed that these materials exhibit semiconductor behavior with energy bandgaps of 2.41 eV and 1.77 eV for Cs 3 Sb 2 Cl 9 and Cs 3 Sb 2 Br 9 , respectively. The Cs 3 Sb 2 Br 9 shows higher absorption and conductivity at comparatively lower frequencies of absorbed light. Furthermore, the magnetic characteristics of the investigated compounds demonstrate that there are no net magnetic moments. The thermodynamic properties analysis indicated a strong correlation between heat capacity and temperature. We have used SLME analysis to determine the theoretical power conversion efficiency for Cs 3 Sb 2 X 9 (X = Cl, Br) perovskites. The determined results of SLME show that Cs 3 Sb 2 Cl 9 and Cs 3 Sb 2 Br 9 exhibit SLME values of 12.63 % and 26.40 %, respectively, at 298.15 K, suggesting that both compounds can be used in solar cells. [ABSTRACT FROM AUTHOR]

• This is the report on overall analyses of Bi and Cu-based 9 DP compounds by replacing the A-site with Cs, Rb, and K atoms, and the X-site with I, Br, and Cl atoms in the A 2 BiCuX 6 structure. • The A-site cationic replacement has put not much impact on the E g as well as the DOS of all 9 compounds. But the Cu-3 d and X- p orbitals are the major contributors of VBM whereas Bi-6 p orbital is the major contributor of CBM. • From the optical properties study, it is confirmed that the most suitable candidate Cs 2 BiCuI 6 DP compound has a ε 2 ω of 8.98, α(ω) of 0.68 × 105 cm−1, n(ω) of 3.4, σ(ω) of 2.24 1/fs, R(ω) of 0.34 and loss function of 2.71, respectively in the visible spectrum. • A comparative study between inorganic Cs 2 BiCuI 6 based FTO/WS 2 /Cs 2 BiCuI 6 /MXene/Pt structured and hybrid organic–inorganic ion ((FA) 2 BiCuI 6) based FTO/WS 2 /(FA) 2 BiCuI 6 /MXene/Pt structured PV cell has been performed using SCAPS-1D software. The Cs 2 BiCuI 6 based one provides an optimum PCE of 30.11 % as compared to (FA) 2 BiCuI 6 based one (20.21 %). • For better optimization of the device parameters, the effect of variation in thickness, defect density, carrier mobility, temperature, R S , and R Sh of the device are performed. Thus, it has been achieved a maximum PCE of 31.25 %, FF of 82.71 %, V OC of 1.24 V and J SC of 30.40 mA/cm2 for absorber thickness of 600 nm, ETL thickness of 130 nm, HTL thickness of 300 nm, N t of 1013 cm−3 for absorber, ETL and HTL each, charge carrier mobility of 20 cm2V−1s−1, temperature of 300 K, R S of 0.5 Ω-cm2 and a R Sh of 106 Ω-cm2, respectively. Presently, the Bi-based 3D A 2 (BB′)X 6 double perovskites (DPs) show an excellent photovoltaic (PV) performance with ambient stability compared to Pb-based counterparts. The structural, electronic, and optical properties analyses of A 2 BiCuX 6 (A=Cs, Rb, K, X=I, Br, Cl) DPs are performed by CASTEP software, and the Cs 2 BiCuI 6 is found to be the best suitable absorber among all of them. The density of states calculation reveals that Cu-3 d and X- p orbitals are the major contributors to valence band maxima (VBM), whereas Bi-6 p orbitals are responsible for the contribution to conduction band minima (CBM). Using SCAPS-1D simulation tool, the impact of variation in thickness, defect density, mobility of charge carriers, series resistance (R S), shunt resistance (R Sh), and device temperature on PV performance of the device has been analysed. The optimised all inorganic FTO/WS 2 /Cs 2 BiCuI 6 /MXene/Pt structured device has provided an excellent PV performance i.e., PCE of 31.25 %, FF of 82.71 %, V OC of 1.24 V, and J SC of 30.40 mA/cm2 using 2D structured ETL (WS 2) and HTL (MXene). This analysis provides an advanced understanding of cheap, environmentally stable, easily obtainable Bi-Cu based DP counterparts, which can be used in the fabrication of PV cells practically. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT study of lead-free X 2 NaIO 6 double-Perovskite. • X 2 NaIO 6 are narrow bandgap semiconductor materials. • They absorb light more strongly in the visible region. • Both of these compounds are mechanically stable, anisotropic, and brittle. • X 2 NaIO 6 are potential candidate for optoelectronic and solar cell applications. The standard lead-free double perovskite X 2 NaIO 6 has become a viable alternative for lead-based perovskites due to its remarkable optoelectronic capabilities, high stability, non-toxicity, and multifunctionality. This study is presented to evaluate the structural, electronic, optical, and mechanical properties of X 2 NaIO 6 (X=Sr, Ba) by applying a first-principles method based on density functional theory (DFT). These investigations were carried out at the level of the generalized gradient approximation (GGA) for the exchange–correlation functional, parameterized by Perdew Burke and Erenzerhof (PBE) within the CASTEP code. The tolerance factors (τ) for Sr 2 NaIO 6 and Ba 2 NaIO 6 are 0.98 and 1.0, confirming the cubic nature of both compounds. Both compounds Sr 2 NaIO 6 and Ba 2 NaIO 6 have direct narrow bandgap values of 1.57 eV and 1.42 eV, respectively. We also presented a comprehensive study of their optical properties. Shear modulus (G), Poisson's ratio (v), elastic coefficient (C ij), anisotropy (A), bulk moduli (B), Young's modulus (Y), and Pugh's ratio (B/G) are computed. The combined electronic, optical, and mechanical investigations show that both materials are suitable for optoelectronic, photovoltaic, and solar cell applications. [ABSTRACT FROM AUTHOR]

The effect of Cl content on total energies of W-Cl system. [Display omitted] • The monoclinic WCl 5 and the trigonal WCl 3 are the more stable phases. • WCl 6 phase may be present in two crystal forms, such as the hexagonal (P -3 m1, 164) β-WCl 6 and the hexagonal (R -3, 148) α-WCl 6. • The obtained bond distance in α-WCl 6 and β-WCl 6 are significantly longer than the mean bond distances in WCl 4 and WCl 5. • Direct Γ-Γ band gap for WCl 3 (1.78 eV), WCl 5 (0.08 eV), β-WCl 6 (1.746 eV) and α-WCl 6 (1.803 eV), while WCl 4 has the metallic character. • The atomic geometry of monoclinic WCl 4 and WCl 5 contain an ordered arrangement of W vacancies. • The PDOS profile of W and Cl are similar throughout the whole energy region, indicating the presence of hybridization between W and Cl electrons. • One shares the charge density at each point between atoms in proportion to the free atomic density, so that the distribution of bound and localized atoms resembles the molecular density. The molecular structures of WCl 6 , WCl 5 , WCl 4 , WCl 3 have been optimized by density functional theory calculations. We report the stability of the phases in the ground state, the total energies and the optoelectronic properties of the W-Cl system. We find that the material having a low tungsten concentration shows a low DOS at the Fermi level, which implies a high resistivity. Both polymorphs of WCl 6 are crystalline solids at room temperature and show the (α- WCl 6) and (β- WCl 6) phases of space group R -3 and P -3 m1 observed at 228 °C. The change in temperature influences the structural, electronic and optical properties. The object of this paper does not concern only the study of all phases, but also one controls the physical states of the molecular materials when they are subjected to polymorphic changes. Calculations on the molecular structure under symmetry indicated an orbitally degenerate ground state with bond distances in good agreement with experiment. [ABSTRACT FROM AUTHOR]

The density function theory (DFT) with GGA and PBE was employed to determine the structural, electrical, and optical characteristics of pure and Cu doped AgZnF 3 type Fluro-perovskite. The structural properties of composite are calculated in realistic agreement with those testified in the literature. The band gap of the hybrid AgZnF 3 is small and indirect. AgZnF 3 contained a calculated band width of 1.52 eV. AgZnF 3 's total electronic properties were principally controlled by the Zn atom, whereas the Zn-d state and the F-p state had a minor impact on its partial electronic properties and state density. Cu doping modified AgZnF 3 's electrical band structure by narrowing the band gap. With increasing doping concentrations, the partial densities of states, which are likewise impacted by doping concentrations decreased. This material is appropriate for a variety of applications due to the improvement in optical characteristics and decrease in the band gap. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phonon and structural stability of Cs 2 SiBr 6 Cs 2 GeBr 6 and Cs 2 SnBr 6 perovskites. • Determined band energy gaps to be favorable for photovoltaic applications. • Mechanical and thermodynamic stability, reliability and compatibility for photovoltaic devices. • IR and Raman active phonon modes in the range 0–400 cm−1 for Cs 2 SiBr 6 Cs 2 GeBr 6 and Cs 2 SnBr 6 perovskites. Exploring prospective materials for energy storage and production is one of the largest confrontation of the century. Solar optoelectronic energy is one of the utmost exceptional renewable resources now a days, due to their small Environmental impact and wide availability. The perovskite type double halides are promising materials for optoelectronic and solar applications. In this article, the optoelectronic characteristics of newly perovskite double halides Cs 2 SiBr 6 Cs 2 GeBr 6 and Cs 2 SnBr 6 are addressed. The calculated band gaps 2.70 eV (Cs 2 SiBr 6), 1.80 eV (Cs 2 GeBr 6), 2.90 eV (Cs 2 SnBr 6) with raising performance for optoelectronic applications. The optical properties are explored by large dielectric constants, high optical absorption coefficients, small optical loss etc. Moreover, the mechanical properties for the studied materials have been performed to confirm the mechanical stability, comactability and reliability of the materials for photovoltaic applications. The thermodynamic and vibrational stability and compatibility has been verified due to negative values of enthalpy, cohesive energies and no soft phonon mode of vibrations. These optoelectronic energy related calculations confirmed that the perovskites type double halides may Cs 2 SiBr 6 , Cs 2 GeBr 6 and Cs 2 SnBr 6 may be novel, stimulating potential materials and can be synthesized experimentally for next generation photovoltaic devices and related applications. [ABSTRACT FROM AUTHOR]

Perovskite will play an important role in the materials study to investigate the different properties. The CASTEP (Cambridge Serial Total Energy Package) code will be used to investigate the material properties. The structural, electronic, thermodynamic, and optical characteristics of novel tungsten-based oxide-perovskite materials WXO 3 (where X = Cr and Hg) were investigated by using first principle calculations (CASTEP) with ultra-soft pseudo-potential PW (plane wave) and GGA (generalized gradient approaches)-PBE (Perdew-Burke-Ernzerhof) exchange correlation-functional. According to the calculations, both compounds have a space group of PM3m with a cubic structure. The results we discovered are entirely novel compounds, as demonstrated by computations. According to calculations, the band structure of WXO 3 has a zero band gap. The graphical interpretations like DOS (density-of-states), partial DOS, and band structure in both perovskite materials reveal conclusive proof of conductive behavior. The presence of ionic bonds is revealed by a study of bonding characteristics shown by Poisson's ratios of 0.71 and 0.49 for WCrO 3 and WHgO 3 , respectively. The WCrO 3 and WHgO 3 optical characteristics have also been studied and assessed. The Fermi level will be so highly overlapped that most of the electrons will lie from the conducting valence band VB to the conduction band CB and vice versa. Thermodynamic characteristics are studied, like Debye temperature, sound velocity, melting temperature, and compressibility. These compounds are extensively used in medical devices, sensitive devices, computer parts, and storage systems. Further investigation will be required on these materials with doping any element to enhance the band gap to study the other properties like photocatalytic and solar cell applications. • A DFT study of Tungsten Based Cubic Oxide Perovskite Materials performed for magnetic properties. • Suggestive materials have a conducting behavior. • The theoretical study shows that Tungsten Based Cubic Oxide Perovskite Materials is most suitable material for superconducting applications. [ABSTRACT FROM AUTHOR]

First principles density functional calculations within the Cambridge Serial Total Energy Package (CASTEP) code applied to widely explore structural, mechanical, electronic and optical properties of MFe 2 O 4 (M = Zn, Cu, Si) ferrites at pressures 0, 5, 10, 15, 20 GPa. The computed X-ray diffraction patterns showed that the lattice parameter values for MFe 2 O 4 (M = Zn, Cu, Si) ferrites were 8.48-8.08 Å, 8.32-8.14 Å, and 8.23-7.87Å, respectively at external pressure 0–20 GPa. The energy bandgap of the MFe 2 O 4 (M = Zn, Si) ferrites revealed a direct nature within the range 1.24-0.0.82 eV and 3.843–3.484 eV versus 0–20 GPa external pressure, respectively. The CuFe 2 O 4 ferrite exhibited indirect bandgaps ranging from 1.167 to 0.992 eV versus 0–20 GPa external pressure. Hence, all the computed values of the band gap showed an inverse response to applied pressure. Mulliken population and the total density of state confirmed that all the bonds Fe–O, Zn–O, Si–O, and Cu–O were covalent. The mechanical properties revealed the cubic stability of MFe 2 O 4 (M = Zn, Cu, Si) ferrites. So, these ferrites proved potential candidates in electrochemical applications. The B/G values presented that the MFe 2 O 4 (M = Zn, Cu) ferrites were ductile and considered suitable candidates in photocatalytic applications. In contrast, the SiFe 2 O 4 ferrite exhibited brittle behavior at all the values of external pressure 0–20 GPa and was deemed helpful to optoelectronic devices. The optical properties showed that MFe 2 O 4 (Zn, Cu, Si) ferrites showed excellent photosensitivity to visible light in photocatalytic, solar cells and optoelectronic applications. [Display omitted] • Study of MFe 2 O 4 (M = Zn, Cu, Si) ferrites at 0–20 GPa by employing CASTEP Code. • Investigation of structural, optical, electronic and mechanical properties. • Study of optoelectronic, solar cell, photocatalytic and electrochemical applications. [ABSTRACT FROM AUTHOR]

Y2MgTiO6:Dy3+/Sm3+ double-perovskite phosphors were synthesized using the high-temperature solid-state reaction method, and their luminescence properties were examined through various techniques, including Rietveld refinement, excitation and emission spectra, Commission Internationale de l'Eclairage (CIE) analysis, and band gap simulation. Ab initio calculations were performed to analyze the band gap and density of states, allowing for the prediction of the effect of Dy3+ and Sm3+ doping on emission intensity. The emission spectra of Y 2 MgTiO 6 (YMTO) doped with Sm3+ and Dy3+ exhibited maximum peaks at 602 nm and 575 nm, respectively, when excited at 325 nm. Both YMTO:Sm3+ and YMTO:Dy3+ demonstrated excellent thermal stability. The CIE coordinates of YMTO doped with 1 mol% Dy3+ were determined to be (0.3771, 0.3804), with a correlated color temperature (CCT) of 4115 K, confirming its suitability for warm white light applications. Introducing 1 mol% and 3 mol% of Sm3+ ions into the Dy3+/Sm3+ co-doped YMTO allowed for adjustable CCT values of 3719 K and 3302 K, respectively, further enhancing their potential for use in warm white light-emitting diodes (WLEDs). [Display omitted] • Y 2 MgTiO 6 :Sm3+/Dy3+ double-perovskite phosphors were synthesized using the high-temperature solid-state reaction method. • The CASTEP successfully elucidated doping effects on band gap and luminescence in phosphors. • The phosphor's CCT can be tuned from 4115K to 3719K and 3302K in the warm white-light range by varying Sm3+ concentration. • Their exceptional thermal stability makes them highly suitable for implementation in LEDs that operate at high temperatures. [ABSTRACT FROM AUTHOR]

Alloys of the Fe-Cr-C-B-Ti alloy system are characterized by brittleness, which can be eliminated by the copper alloy, while corrosion resistance and abrasive wear resistance are significantly reduced. In this article, comprehensive investigations are carried out on the microstructure and mechanical properties of the proposed high-copper boron-containing alloy 110Cr4Cu7Ti1VB. Systematic theoretical and experimental studies encompassed thermodynamic calculations in ThermoCALC, production of flux-cored wires for hardfacing and welding, receipt of SEM images, acquisition of load and unload diagrams (discharge) via instrumental indentation on various phases of the deposited metal, and determination of chemical composition at indentation points through local chemical analysis. Mechanical properties of some phases such as γ-Fe phase (austenite), hemioboride Fe 2 (В,С) and boron cementite Fe 3 (В,С) and titanium carbide TiC in Fe-Cr-C-B-Ti-Сг alloy were determined by using density functional theory (DFT) implemented in the CASTEP code. We also compared these compounds; properties with other available commercial compounds, where available. With the knowledge of calculated elastic constants, the moduli, the Pugh's modulus ratio G/B, the Poisson's ratio v and the hardness of the title phases, 110Cr4Cu7Ti1VB were further predicted and discussed., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)