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Defect pyrochlores are unique structures that contain built-in imperfections, exhibiting a range of beneficial properties that make them ideal for various high-tech applications. In this study, the electronic and thermoelectric properties of Pb2B2O6 (B = Ir, Ru, Tc) defect pyrochlores were calculated using the full-potential linearized augmented-plane-wave (FP-LAPW) method within the framework of density functional theory (DFT). The Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) and modified Becke-Johnson mBJ potentials were employed to calculate the geometric properties and electronic structure. To assess the effect of electron localization in the d-subshell of transition metals on the electronic structure, the DFT+U approach was adopted, setting U values in the range of 1–2. The large cohesive energies confirm the thermal stability of these defect pyrochlores. The results reveal the metallic nature of Pb2B2O6 compounds, as their valence band (VB) and conduction band (CB) overlap at the Fermi level. Because of the four unpaired electrons in the 4d-states of Tc and the possible inner shell transition from the fully occupied 5s to an empty 5p-state, the total density of states (TDOS) for Pb2Tc2O6 shows prominent peaks near the Fermi level, leading to higher electrical conductivity of Pb2Tc2O6. Thermoelectric calculations indicate that Pb2Ir2O6 and Pb2Ru2O6 are n-type materials, while Pb2Tc2O6 is a p-type material, suggesting the suitability of these materials for practical applications in thermoelectric devices. [ABSTRACT FROM AUTHOR]

This Study uses density function theory calculations to examine the structural, elastic, optoelectronic, and thermal properties of lithium-based double perovskites Li2AgBiZ6 (Z = Cl, Br, I). The perovskite materials have good structural stability, as demonstrated by our computations, with a tolerance factor of 0.96, 0.95, and 0.93, respectively, and formation energy of -2.11, -1.89, and − 1.65 eV. The elastic constants of materials with cubic symmetry are examined to differentiate between their ductile or brittle nature, mechanical strength, minimum lattice thermal conductivity, melting point, Debye temperatures, and anisotropy. We utilized TB-mBJ potential to predict the electronic characteristics. Li2AgBiCl6, Li2AgBiBr6, and Li2AgBiI6 are semiconductors with indirect band gaps of 2.30, 1.83, and 1.20 eV, respectively. The low effective mass, as well as the binding energy of excitons, strong absorption in the visible region, and low reflectance, make them important materials for photovoltaic cells. Thermoelectric studies suggest moderate ZT values of 0.72, 0.63, and 0.58. Hence, the explored perovskite materials have promising features for solar energy generation and thermoelectric devices. [ABSTRACT FROM AUTHOR]

The present investigation thoroughly evaluates the structural, optoelectronic, elastic, and transport properties of Rb2CuSbZ6 (where Z = F, Br, and I). The assessment includes the application of the Born-Huang criterion, the tolerance factor, and the formation energy to ensure the thermodynamic, structural, and mechanical stability of the compounds. Analysis of elastic and mechanical parameters supports their ductile nature and directed bonding capabilities. Utilizing the Tran and Blaha-modified Becke-Johnson approximations, the study estimates the band gap values of Rb2CuSbF6, Rb2CuSbBr6, and Rb2CuSbI6 as 1.37 eV, 0.72 eV, and 0.36 eV, respectively, indicating characteristics of indirect bandgap semiconductors. Extensive scrutiny of optical parameters reveals remarkable dielectric and absorption capabilities within the visible light spectrum. Consequently, Rb2CuSbZ6 (where Z = F, Br, and I) double perovskites are recommended for utilization in solar cell applications and optoelectronic devices. Furthermore, assessments of their transport properties indicate that the examined compounds display attributes of a p-type semiconductor, alongside an exceptionally low thermal conductivity and a high power factor, making them highly suitable for energy harvesting devices. [ABSTRACT FROM AUTHOR]

The spintronic is merging technology that controls the functionality of devices with a spin of electrons to fasten speed and shrink the size. Therefore, the magnetic properties and effect of mechanical, thermodynamic, and thermoelectric on Rb2VCl6 and Rb2CrCl6 have been addressed comprehensively. Heisenberg model has been implemented for Curie temperature and polarization density mechanism for spin polarization. The crystal field, exchange energies, and exchange constants are analyzed to address the role of electron spin in ferromagnetism. The integer magnetic moments (3.0 & 4.0)µB for Rb2VCl6 and Rb2CrCl6 are also calculated, showing 100% spin polarization. Both mechanical and Boltzmann mechanisms reported the ultralow value of thermal conductivity. The elastic constant for cubic structures and Poisson (0.28, 0.25) and Pugh's (1.95, 1.78) conditions for ductile and brittle nature are elaborated. The Debye temperature, melting temperature, and hardness are also important for device fabrication. Finally, the power factor and Figure of merit scale have addressed thermoelectric performance, increasing thermoelectric applications' importance. [ABSTRACT FROM AUTHOR]

This article comprehensively explores the structure, stability, mechanical, optoelectronic, and thermoelectric aspects of the emerging double perovskites A2YCuZ6 (A = Rb, Cs and Z = Cl, Br). The structural and mechanical characteristics are estimated using the PBE-GGA functional, whereas the optoelectronic and thermoelectric characteristics are computed using the modified Becke and Johnson potential. Tolerance factor, formation energies, and Gibbs free energies have validated the cubic phase and thermodynamic stability. The anticipated elastic values indicated that all the materials exhibited mechanical stability, ductility, and anisotropic behavior. The computed electronic features verified that Rb2YCuCl6, Rb2YCuBr6, Cs2YCuCl6, and Cs2YCuBr6 have indirect band gaps of 1.95, 1.30, 1.55, and 1.2 eV, respectively. This work also explores the optical response in the energy range 0 to 6 eV in terms of polarization, refractive index, absorption, and optical conduction. The visible and ultraviolet ranges of light are both significantly absorbed, making these materials optimal for use in solar systems. The BoltzTraP code has been used to calculate the transport parameters, demonstrating the p-type semiconductors nature of these materials. Further, the significant merit values of 0.77, 0.83, 0.82, and 0.81 at room temperature for analyzed materials suggest their potential applicability in thermoelectric devices. Hence, the investigated double perovskites, which are not empirically validated, have been recommended as extremely suitable alternatives for creating various energy conversion applications. [ABSTRACT FROM AUTHOR]

Lead-free halide double perovskites (HDPs) have emerged as aspirant members of the optoelectronic and thermoelectric (TE) materials family due to their non-toxicity, tunable and noticeable performances. Herein, the structural, mechanical, thermodynamic, optoelectronic, and TE properties of novel Rb2CuMF6 (M = As3+, Bi3+) HDPs are comprehensively investigated. This study has been performed using accurate first principle calculations with the Boltzmann transport theory. The evaluated elastic constants ensure their structural and thermal stability in cubic phase and anisotropic with ductile behavior. Using Tran-Balaha modified Becke-Johnson (TB-mBJ-GGA) potential, indirect semiconducting band gaps of 1.43 eV and 1.27 eV are recorded for Rb2CuAsF6, and Rb2CuBiF6, respectively. Correlated analyses of the wavelength-dependent optical properties are conducted. The studied HDPs exhibited different optical absorption abilities in both UV and VIS working regions. Besides, the entire TE properties are addressed for n- and p-type doping in a wide operating temperature range. The p-type doping is found to be effective in enhancing the TE performances of both HDPs. The highest figure of merit (ZT)max = 0.994 is recorded at 300 K for intrinsic Rb2CuMF6 (M = As3+, Bi3+). Accordingly, the favorable combination of the present outcomes makes Rb2CuMF6 (M = As3+, Bi3+) an interesting candidate for widespread optoelectronic and TE applications in a wide working temperature range. [ABSTRACT FROM AUTHOR]

Lead‐free double perovskites are unique materials for transport and optoelectronic applications that use clean resources to generate energy. Using first‐principle computations, this study thoroughly investigates the structural, thermoelectric, and optical attributes of A2TlAgF6 (A = Rb, Cs). Tolerance factor and formation energy estimates are used to verify that these materials exist in the cubic phase. Elastic constants with high melting temperature values are ductile when evaluated for mechanical stability using the Born stability criterion. The optical absorption band is adjusted from 2 to 4 eV via band gaps of 1.88 and 1.99 eV, as indicated by band structures. Analysis of optical properties reveals perfect absorption in the visible spectrum, whole polarization, and low optical loss. Furthermore, thermoelectric properties are assessed at 300, 500, and 700 K in the range of −0.5 to 3 eV for chemical potential (μ). The materials exhibit significant improvements in the Figure of Merit scale due to their elevated electrical conductivity, Seebeck coefficient, and extremely low thermal conductivity values. [ABSTRACT FROM AUTHOR]

This article introduces and examines a new type of lead-free double perovskites, K2InSbX6 (X = Cl, Br) for their potential use in optoelectronic and thermoelectric devices. The investigation is conducted through theoretical exploration. The physical features of the materials were investigated using density functional theory. Both compounds are found stable in their cubic structure. Elastic constants and negative formation energies computed for K2InSbX6 demonstrate its mechanical and thermodynamic stability. According to the computed Poisson, Pugh's ratio, and anisotropy, both materials are brittle and show anisotropic behavior. Furthermore, the calculated findings show that K2InSbCl6 and K2InSbBr6 have direct bandgap values of 1.31 and 1.22 eV, respectively. Optical analysis reveals a notable ability to absorb visible and near-UV radiation. Perovskite K2InSbX6's excellent light absorption capabilities and narrow band gap make it a great choice for utilization in solar cell applications and other optoelectronic devices. Furthermore, the findings of transport characteristics indicate that the materials possess exceptional electrical and thermal conductivity and are projected to exhibit optimal thermoelectric capabilities at a temperature of 300 K. [ABSTRACT FROM AUTHOR]

Recently, many studies have been done on MXene (2D titanium carbide) for energy storage applications. It possesses outstanding features like hydrophobicity, conductivity, and particularly strong surface redox reactivity, which are essential for energy storage applications. Despite these exceptional properties, MXene's electrochemical performance is significantly impacted by certain deficiencies, such as the inability to assemble MXene sheets. To prevent MXene sheets from restacking, the spaces between them must be filled with an appropriate material. Metal-organic frameworks (MOFs) for electrochemical applications have also been extensively studied. Due to their high crystallinity, porous structure, and substantial surface area, MOFs find diverse applications, but their efficacy as electrode materials is hindered by a lower specific capacity and charging/discharging rate. Addressing these limitations, combining MOFs with suitable materials is preferred for enhanced performance. This study suggests an innovative approach: a composite between Cu-BTC MOF and N-MXene. By shortening both the ion/electron diffusion pathways and improving the electroactive sites, the prevention of MXene sheet restacking was achieved, leading to exceptional specific and rate capacity in the composite with MOFs. The Cu-BTC/N-MXene-decorated electrode exhibited energy and power density reaching approximately 65.23 W h kg-1 and 923 W kg-1 in a two-electrode (real device) configuration. Cu-BTC/N-MXene//N-MXene retained 99% of its capacity and a coulombic efficiency of 92% after 8000 alternate GCD cycles. The findings of this investigation highlight the significant potential of employing the innovative electrode material Cu-BTC/N-MXene for supercapattery applications. [ABSTRACT FROM AUTHOR]

In this work, theoretical investigations were performed for the structural, elastic, optoelectronic, thermodynamic, and thermoelectric characteristics of barium ceroplatinate Ba2CePtO6 double perovskite oxide. The direct band gaps 1.518 eV and 1.385 are calculated with TB-mBJ potential, and PBE-GGA approximation. The findings of elastic constants C11, C12 and C44, ensure the mechanical stability, ductile nature, anisotropic, Debye temperature, and ionic bonding. In visible and ultraviolet spectrums, Ba2CePtO6 exhibits a high absorption coefficient (> 105 cm−1), low optical reflectivity, low electron energy loss and excellent refractive index. Finally, the thermoelectric properties are computed using BoltzTraP code. At room temperature the figure of merit has been reported as 0.84 and 0.998. Therefore, the reported results are likely to serve as an inspiration for the forthcoming experimental and theoretical investigations. [ABSTRACT FROM AUTHOR]

We investigated the magnetic and thermoelectric properties of REMoN3 (RE = La, Ce, Pr, Nd, Sm) perovskites using the full potential linearized augmented plane wave (FP‐LAPW) method. To overcome the problem of underestimation of electronic interaction, we employed the DFT + U approach to accurately map the electronic structure of these compounds. Our study shows an increasing trend in the magnetic moments with the increasing number of unpaired electrons in RE. Among these compounds, SmMoN3 possesses a large magnetic moment, which is suitable for applications such as memory devices and sensors. Interestingly, all these perovskites display ferromagnetic behavior except CeMoN3, which exhibits an antiferromagnetic nature. Furthermore, our analysis indicates n‐type thermoelectric behavior in all these materials. The compound, namely PrMoN3, exhibits a high figure of merit among REMoN3, which can be improved by modifying the lattice sites. [ABSTRACT FROM AUTHOR]

Hydrogen storage has garnered significant interest in recent years due to hydrogen's potential as an energy source. Research in this area focuses on exploring the hydrogen storage capabilities of newly identified compounds. This study presents a characterization of CsXH 3 (X = Ca, Sr, Ba) perovskite-type hydride compounds for the first time to assess their potential for hydrogen storage applications. The structural, mechanical, electronic, optical, and thermoelectric responses of studied hydrides are examined utilizing WIEN2k software. The calculated formation energy (ΔH F) values for CsCaH 3 , CsSrH 3, and CsBaH 3 are noticed as −3.20, −2.80, and −2.65 eV, respectively, ensuring their thermodynamic stability of these hydrides. The studied compositions exhibit their direct band gap of 3.21, 2.75, and 2.25 eV, which align well with other theoretical studies. Analysis of optical behavior exhibits that absorption of electromagnetic radiation starts in visible spectra and becomes maximum in the UV range. Furthermore, temperature-dependent transport characteristics including σ, κ e , S, PF, C v, and ZT are evaluated utilizing the BoltzTraP code. The large value of ZT suggests their suitability for thermoelectric application. For CsCaH 3 , CsSrH 3, and CsBaH 3 , the gravimetric ratios for hydrogen storage are 1.75, 1.34, and 1.10 wt %, respectively. This computational analysis marks a significant advancement in understanding different physical properties and possible implications of these hydrides in the fields of thermoelectric and hydrogen storage. [Display omitted] • The perovskites hydrides are emergent materials for hydrogen storage. • Structural, thermodynamic and thermally stable. • Thermodynamic, structural, and mechanical stability. • The absorption bands of light energy exist in the ultraviolet to the visible region. • The Large Debye and melting temperatures make them suitable for industrial applications. [ABSTRACT FROM AUTHOR]

A promising metal-organic framework (MOF) called Zeolitic Imidazolate Framework-8 (ZIF-8) stands out for its electrochemical applications. Its versatility in physicochemical properties makes it a strong candidate for breakthroughs in energy storage and electrochemical water splitting. The electrode nanomaterials lower specific capacity, small charging/discharging rate, and low conductivity limit its supercapacitor and hydrogen evaluation reaction (HER) applications. The ZIF-8 zeolite structure was decorated with tungsten carbide (WC) to overcome these issues. These modifications result in improved porosity, surface area, density, and pore size, shape, and structure. These characteristics contribute significantly to enhanced electrochemical activity. ZIF-8 MOF/WC nanocomposites have excellent dispersion and stability due to their porosity and strong connection between embedded WC nanoclusters and the framework. The prepared electrode showed a 118.11 mV overpotential and 36.45 mV/dec Tafel slope throughout HER activity. ZIF-8 MOF/WC was used for electrochemical studies and to make a hybrid energy storage device using activated carbon (AC). The hybrid supercapacitor had higher energy and power densities (87 W h/kg and 850 W/kg). The theoretical technique (Dunn model) was also employed to analyze experimental results more thoroughly. [Display omitted] • ZIF-8 MOF/WC composite used for supercapattery and electrochemical water splitting. • An outstanding specific capacity of 2182 C/g is obtained. • Astounding 87 Wh/kg energy and 850 W/kg power densities are proposed. • ZIF-8 MOF/WC exhibits a low η (118.11 mV@10 mA/cm2) and low Tafel slope (36.45 mV/dec). • Estimated 96 % capacity retention after 20000 charge-discharge cycles. [ABSTRACT FROM AUTHOR]

The potential of hydrogen as an energy source has positioned hydrogen storage as a prominent research domain in the current era. Innovative perovskite compounds have emerged as a focal point for investigating hydrogen storage applications. In this study, we have investigated the RbXH 3 (X = Mg/Ca/Sr/Ba) perovskite hydrides by density functional theory (DFT). Our exploration encompasses the analysis of electronic structures, mechanical stability, elastic properties, and optical and thermoelectric response. The cubic crystal structures of RbXH 3 are revealed, with lattice constants of 4.13, 4.54, 4.82, and 5.17 Å for X = Mg, Ca, Sr, and Ba, respectively. Electronic structure calculations indicate ionic bonding with a wide bandgap reduced with increasing size of X. Mechanical stability, essential for meeting the Born stability criterion, is scrutinized, whereas Pugh criteria suggest a ductile and hard nature for these materials. Thermoelectric characteristics regarding electrical and thermal conductivity, Seebeck coefficient, and power factors are elaborated. The figure of merit emphasizes their suitability for thermoelectric devices. The Gravimetric ratios indicate the hydrogen storage capability, potentially contributing to various transportation and power applications. [Display omitted] • This manuscript presents a pioneering investigation into the potential of RbXH 3 (X = Mg/Ca/Sr/Ba) perovskites for hydrogen storage, offering a fresh perspective on sustainable energy materials. • A state-of-the-art first-principle density functional theory (DFT) based calculations are carried out to comprehensively explore the structural, electronic, and hydrogen storage properties of these alkaline metal-based hydrides. • Structural stability of RbXH 3 perovskites, shedding light on their suitability as stable materials for practical applications in hydrogen storage systems. [ABSTRACT FROM AUTHOR]