Search

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 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]

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]

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]