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1.
J Mol Model ; 30(2): 32, 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38197994

ABSTRACT

CONTEXT: The study investigates the impact of Hubbard U correction and spin-orbit coupling (SOC) on the structural, mechanical, electronic, and optical properties of Ti[Formula: see text]O[Formula: see text] and SrTiO[Formula: see text] compounds. The research is motivated by the potential applications of these materials in photovoltaics, with a focus on understanding their properties for such use. The ductility, ionicity, and mechanical stability of both compounds at zero pressure are assessed, indicating their potential as resilient materials. Also, the compounds display high refractive indices and absorption coefficients, indicating their suitability for solar harvesting applications. The predicted bandgaps align primarily with the UV-Vis areas of the electromagnetic spectrum, highlighting their potential in this domain. METHODS: Computational techniques employed in this study are density functional theory (DFT) with and without spin-orbit coupling, as well as DFT+U methods, implemented using the Quantum ESPRESSO (QE) package. The study adopts the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, while employing a plane-wave basis set with an energy cutoff of 50 Ry for wavefunctions and 500 Ry for charge density.

2.
Heliyon ; 9(8): e18531, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37554828

ABSTRACT

In this study, the structural, electronic, mechanical, optical, and thermoelectric properties of the cubic half-Heusler compound ZrCoY(Y[bond, double bond]Sb and Bi) obtained using first-principles calculations are presented. The following exchange-correlation functionals have been employed: Generalized Gradient Approximation with Perdew-Burke-Ernzerhoff (GGA-PBE), Generalized Gradient Approximation with Perdew-Burke-Enzerhoff for solids (GGA-PBESol) and Local Density Approximation (LDA). Both ZrCoSb and ZrCoBi compounds are mechanically and dynamically stable, based on the elastic and phonon properties analysis. The calculated electronic band gaps for both compounds are about 1 eV, as predicted by all the three functionals. Since it is noted that GGA-PBE functional is most favourable for predicting structural properties and the energetic stability of ZrCoSb and ZrCoBi compounds, it is further used to calculate their thermoelectric properties. Within the energy range of 0-40 eV, the refractive index, dielectric constant, and energy loss function of ZrCoSb and ZrCoBi compounds are calculated. The possibility of electronic transition from the valence band maximum (VBM) to the conduction minimum band (CBM) is confirmed by the occurrence of absorption peaks in the visible range. For the evaluation of thermoelectric properties, the p-type and n-type doping attained Seebeck coefficients of 1800 and -1800 µVK-1 at 300 K, respectively. The maximum peak of 17 × 1011 W/m s K2 is attained in n-type doping, according to the power factor results.

3.
Heliyon ; 4(7): e00681, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30094361

ABSTRACT

Nanostructured mesoporous titanium dioxide (TiO2) particles with high specific surface area and average crystallite domain sizes within 2 nm and 30 nm have been prepared via the sol-gel and hydrothermal procedures. The characteristics of produced nanoparticles have been tested using X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FTIR), and Raman Spectroscopy as a function of temperature for their microstructural, porosity, morphological, structural and absorption properties. The as-synthesized TiO2 nanostructures were attempted as catalysts in Rhodamine B and Sudan III dyes' photocatalytic decomposition in a batch reactor with the assistance of Ultra Violet (UV) light. The results show that for catalysts calcined at 300 °C, ∼100 % decomposition of Sudan III dye was observed when Hydrothermal based catalyst was used whiles ∼94 % decomposition of Rhodamine B dye was observed using the sol-gel based catalysts. These synthesized TiO2 nanoparticles have promising potential applications in the light aided decomposition of a wide range of dye pollutants.

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