Adsorption and solar light activity of noble metal adatoms (Au and Zn) on Fe(111) surface: a first-principles study.

Noble metals such as gold (Au), zinc (Zn), and iron (Fe) are highly significant in both fundamental and technological contexts owing to their applications in optoelectronics, optical coatings, transparent coatings, photodetectors, light-emitting devices, photovoltaics, nanotechnology, batteries, and thermal barrier coatings. This study presents a comprehensive investigation of the optoelectronic properties of Fe(111) and Au, Zn/Fe(111) materials using density functional theory (DFT) first-principles method with a focus on both materials' spin orientations. The optoelectronic properties were obtained employing the generalized gradient approximation (GGA) and the full-potential linearized augmented plane wave (FP-LAPW) approach, integrating the exchange-correlation function with the Hubbard potential U for improved accuracy. The arrangement of Fe(111) and Au, Zn/Fe(111) materials was found to lack an energy gap, indicating a metallic behavior in both the spin-up state and the spin-down state. The optical properties of Fe(111) and Au, Zn/Fe(111) materials, including their absorption coefficient, reflectivity, energy-loss function, refractive index, extinction coefficient, and optical conductivity, were thoroughly examined for both spin channels in the spectral region from 0.0 eV to 14 eV. The calculations revealed significant spin-dependent effects in the optical properties of the materials. Furthermore, this study explored the properties of the electronic bonding between several species in Fe(111) and Au, Zn/Fe(111) materials by examining the density distribution mapping of charge within the crystal symmetries.

From Molecules to Devices: Insights into Electronic and Optical Properties of Pyridine-Derived Compounds Using Density Functional Theory Calculations.

In this study, we delve into the electronic structure, spectroscopic, and optical properties of five benzo derivatives of pyridine, namely, 5-(4-chlorophenyl)-2-fluoropyridine (1), 2-fluoro-5-(4-fluorophenyl)pyridine (2), 4-(2-fluoropyridin-5-yl)phenol (3), 5-(2,3-dichlorophenyl)-2-fluoropyridine (4), and 5-(5-bromo-2-methoxyphenyl)-2-fluoropyridine (5). Utilizing quantum chemical density functional theory calculations at the B3LYP and Perdew-Burke-Ernzerhof levels of theory combined with the 6-311G(d,p) and 6-311++G(d,p) basis sets, we investigated the electronic and optical characteristics of these compounds. Band structure calculations were conducted for their crystalline structures, revealing a direct band gap varying from 3.018 to 3.558 eV, with the valence band maximum and conduction band minimum located at the G point in the Brillouin zone. The optical properties were analyzed, including the dielectric functions, reflectivity, and refractive index. Notably, reflectivity was found to be minimal in the photon energy range of 0.0-3.0 eV, and the static refractive index, n(0), ranged from 1.55 to 1.70. The research also involved assessing the reactivity of the compounds through calculation of the frontier orbital energy gaps (ΔE), indicating a significant charge transfer and high reactivity. Additionally, we performed frequency analysis to unveil the Fourier-transform infrared spectra of compounds 1-5 at room temperature. Molecular electrostatic potential surfaces of the optimized structures were employed to map the electrophilic and nucleophilic regions of the compounds. This investigation provides a comprehensive understanding of the electronic and optical properties of these pyridine derivatives, shedding light on their potential applications in optoelectronics.