Current Materials Science - Volume 18, Issue 2, 2025

The present work deals with DFT-based theoretical investigations on pristine and metal (M = Na, Mg, and Al) substituted zinc oxide nanotube (M-ZnONT). The investigation advocates a change in the electronic bandgap of ZnONT on the respective substitution of Zn with Na, Mg, and Al. The forbidden energy gap vanishes on Na incorporation, while Al substitution brings the gap to 0.08eV. The formation energy calculations suggest the feasibility of these metallic substitutions, of which Na incorporation is most favorable. Partial density of state (PDOS) analysis is well correlated with band structures. A localized state above the Fermi level contributed from Al-3p in Al-ZnONT suggests the electronic affinity of Al-ZnONT for incoming nucleophiles. Our optical investigation shows large ε1(ω) values in far-infrared (IR) and visible (Vis) regions for M-ZnONT. Hence, suggests a high refractive index for the metal-substituted ZnONTs in the prescribed range. The study suggests that photonic energy loss due to attenuation, bending, and absorption are weak in ultra-violet (UV) and far UV regions i.e, (3eV to 8eV). However, for the respective energy range, high reflectivity is predicted. This indicates the nanotubes as a good reflector for the purpose of coating material surfaces where high reflection is demanded.

Finding electronic and optical properties of functionalized ZnONT using DFT method.

All calculations have been performed in the framework of density functional theory (DFT) using Troullier Martins’s norm-conserving pseudo-potential.

Metal incorporation at the surface of ZnONT consequent intense ε1(ω) values in far infra-red and visible regions for M-ZnONT.

The investigation suggests that the metal-substituted nanotube is a good reflector for coating material surfaces where high reflection is demanded.

Two-dimensional (2D) nanosheets have been widely explored for sensing toxic gases by investigating structural and electronic properties. However, the optical investigation could be an alternative approach to address the sensing capability of the nanosheets. In the present work, the electronic and optical investigation is performed using density functional theory (DFT) to find out the sensitivity of boron-nitride nanosheet (BNNS) towards NH3 and NO2 gas molecules. Electronic investigation suggests a weak binding of NH3 and NO2 with the 2D sheet, with appreciable changes in the BNNS electronic density of state (DOS) on NO2 interaction. NH3 interaction could not affect the BNNS DOS except for lowering of band dispersion graph across the Fermi level. NO2 interaction brings a noticeable change in spectra, primarily red-shift. Based on this information, tuning is also observed in different optical descriptors, i.e., dielectric constant, refractive index, and extinction coefficient of NO2 interacted BNNS. All these findings advocate sensitivity toward the gas molecule of the 2D sheet could be realized from the optical frame.

Finding NH3 and NO2 affinity of Boron-Nitride Nanosheet Through Optical Spectrum: A DFT Study.

The calculations are performed in the framework of density functional theory (DFT) using Troullier Martins’s norm-conserving pseudo-potential.

The NO2 interacted BNNS shows the optical spectra get red-shifted, and the primary reason is the available NO2 molecular state below the fermi level as shown in PDOS analysis.

The present investigation predicted an almost similar ε2 spectra pattern of BNNS and NH3-BNNS except in shallow region 7 eV-10 eV; a weak absorption band appeared in this region after NH3 absorption. The main concern for this deviation is the electronic transitions taken from the valance N-p-state of NH3 to the conduction band (primarily π* in nature) of BNNS.

Synthetic surfactants, when released into the environment, do not degrade completely and show harmful effects. To minimize the damage to the environment and to introduce milder surfactants, it was necessary to introduce bio-surfactants.

Optimization of the yield is performed by using a design expert model. The analysis of the product was carried out by using different techniques. The formulation of the personal care product was prepared by using the sophorolipid produced.

Different compositions of raw materials are used, suggested by Design expert software to optimize the yield of the sophorolipid. Fermentation was performed by the shake flask method at specified conditions in the incubator shaker for the synthesis. The extraction and separation of the sophorolipid were done by the solvent extraction method.

The predicted product yield value is close to the actual value of the product obtained, which indicates the model is accurate to use. The effect of the raw materials on the yield can be studied with the design expert model. The product is analyzed for its composition and properties with different analysis methods.

Mathematical modelling is very helpful in predicting the optimum reaction condition and improving the yield of a particular bio-process. The RSM model of design expert software can be further utilized to carry out the in-detail study of the various factors and their effect on optimizing the yield. The sophorolipid can be used in different formulations as a greener and safe alternative to a chemical-based surfactant.

This work aims to provide a detailed analysis of a biomedically relevant compound with the chemical name 5-methoxybenzimidazole.

The compound was analyzed for its thermochemical, charge distribution, electrical, nonlinear optical, atomic force, and atomic orientations. Different ab-initio methods and their combinations (ONIOM1 and ONIOM2) were used for quantum mechanical simulations and identification of the compound.

For 5OB, a detailed vibrational analysis of 5OB was performed. The compound is found to be highly active due to electronegative Nitrogen and the highly resonating structure of benzimidazole. Its significant optical nonlinearity was proved by sizeable static hyperpolarizability. From APT analysis, we found that there is a difference in the results given by ONIOM and DFT while the results shown by the two ONIOM methods gave almost similar distribution patterns. By performing NLO, ONIOM 2 is found to be better than ONIOM 1.

After the analysis, we found that computationally cheaper ONIOM 2 is compatible with DFT for the 5OB compound.

The objective of this work was to study in more detail the dielectric permittivity and dielectric losses at different frequencies. It is well known that adding ions increases the dielectric constant and increases the dielectric loss as well as conductivity. Furthermore, the real part of the dielectric constant decreases with increasing frequency. Dielectrics are used as a capacitor for storing energy and a transformer for insulating and cooling agents. To enhance the performance of a semiconductor device, high-permittivity dielectric materials are used. Another aim of this study was to gain a better understanding of how frequency influences the dielectric and electrical properties and what are the mathematical forms of these dependencies. With this aim, magnetic mixed metal oxide systems ZnMn1-xNixFexO4 (x=0.0, 0.25, 0.5, 0.75, and 1.0) have been synthesized in this work using wet chemical approaches. The prepared mixed-metal oxide nanomaterials have been characterized using analytical techniques, viz., XRD, FT-IR, SEM, TEM, VSM, TGA/DTA, etc.

Nanoparticles of ZnMn1-xNixFexO4 (x = 0.0, 0.25, 0.5, 0.75, and 1.0) have been synthesized using the lucrative as well as eco-friendly chemical sol-gel technique. According to the Debye-Scherrer equation, the generated nanoparticles had an average crystallite size of 34 nm, and the ferrite sample showed a cubic structure. Two absorption bands at 411-455 and 595 cm^-1 in FT-IR spectroscopy have evidenced the aforementioned structure to exist in the manufactured samples. The magnetic curves demonstrated that after nickel replacement, the values of coercivity and saturation magnetization altered. Between 20 Hz and 1 MHz, a dielectric behavior demonstrated conductivity and dielectric dispersion owing to interfacial polarization, as well as the interior of grain boundaries.

In the present case, it has been observed that the dielectric behavior decreased with increasing Ni concentration in the above-synthesized compositions. Such change may be due to the increase in resistivity of Zn-Mn ferrite with the substitution of nickel concentration and it has indicated the dielectric behavior to be directly proportional to the square root of conductivity.

Current research has demonstrated that ferrite nanoparticles have sparked substantial interest due to their high surface-to-volume ratio, distinctive tunable capabilities, hydrophilic nature, biocompatibility, and exceptional magnetic properties. The samples' structural, microstructural, magnetic, and electrical characteristics, have also been examined.