Search

The sulfuric acid-doping polyaniline (H-PANI-HSO4) are applied to conduct the electrochemical measurement and simulation calculation to investigate the capacitance, electronic structure and energy band properties. The H-PANI-HSO4 growing on graphite carbon paper (H-PANI-HSO4/GCP) is applied as an electroactive electrode to investigate electrochemical properties. The Faradaic capacitance of H-PANI-HSO4/GCP electrode is ascribed to the reversible redox reaction of bisulfate anion doping/dedoping protonated PANI (H-PANI). Cyclic voltammetry measurement at a scan rate of 5mVs−1 determines an equivalent mean response current of 0.64Ag−1 and a capacitance of 128.35Fg−1. Galvanostatic charge–discharge measurement determines specific capacitance from 129.06 to 116.88Fg−1 at current densities from 0.5 to 2.5Ag−1. Cyclic voltammetry-based capacitance at equivalent current density of 0.64Ag−1 is in accordance with galvanostatic charge–discharge-based capacitance at the current density of 0.57Ag−1. Electrochemical impedance spectrum measurements indicate that H-PANI-HSO4/GCP exhibits lower charge-transfer resistance, much lower Warburg resistance, higher quasicapacitance than H-PANI-HSO4 to approaching ideal capacitor. Density functional theory calculations indicate that H-PANI-HSO4 has a higher density of states (10.6 electron/eV) and lower bandgap energy (0.481eV) than H-PANI (5.24 electron/eV, 1.449eV), indicating its enhanced electronic conductivity. The electronic bandgap energy is accordingly decreased from 0.263eV for H-PANI-HSO4/GCP to 0 for H-PANI-HSO4/GCP. Electrochemical measurement and simulation calculation investigation proves that H-PANI-HSO4/GCP electrode with anion-doped and protonated state exhibits higher electronic conductivity and capacitance performance to act as superior electroactive material. [ABSTRACT FROM AUTHOR]

Gas sensors are essential devices to detect harmful gases that are present in the environment. Metal oxide semiconductors (MOSs) are used as sensing materials to detect harmful gases. Some of the metal oxides, like ZnO, SnO2, WO3, NiO, etc. have been used to detect the gases. This paper provides a theoretical study of gas sensing using MOSs. Many programs are available for the theoretical Density Functional Theory (DFT) approach. The theoretical calculation provides many properties about the sensing material, like electronic properties, magnetic properties, charge difference calculation, and Vander wall interaction between the sensing material surface and adsorbing molecule. The nanostructure provides better gas sensing performance due to its high surface-to-volume ratio. This paper is based on the DFT study and provides gas-sensing results using electronic properties. [ABSTRACT FROM AUTHOR]

In this paper, theoretical investigations of structural, elastic and thermal properties of Zn3P2 material were done using Quantum ESPRESSO code based on density functional theory. The generalized gradient approximation (GGA) exchange correlation-functional helped to model the atomic interaction. First, the structural optimization procedure was carried out, and hence, the optimized structural parameters were utilized to obtain six independent elastic constants C 1 1 , C 1 2 , C 1 3 , C 3 3 , C 4 4 , and C 6 6 for the Zn3P2 tetragonal structure. Accordingly, these elastic constants were used to determine the elastic moduli such as the Bulk modulus, Young's modulus, and shear modulus, as well as other mechanical parameters such as Pugh's ratio, Poisson's ratio, anisotropic ratio, sound velocities and Debye temperature. Calculations of thermodynamic properties such as vibrational energies, vibrational free energies, and fixed volume heat capacities, were performed within the implementation of the Thermo_pw code. Elastic calculations confirmed that this compound is characterized by mechanical stability at zero pressure and 0K temperature, ionic bonding, a high degree of anisotropy, and typical ductility. An observable increase in Debye vibrational energies, entropies and constant volume heat capacities of this compound with increasing temperature was detected throughout the thermodynamic calculations, unlike vibrational free energy which revealed a pronounced decrease as temperature increased. [ABSTRACT FROM AUTHOR]

In this paper, we studied the magnetic stability, structural, elastic and electronic properties of Ir2FeAl full Heusler compound in the regular phase (Cu2MnAl, prototype L2 1) , by using the first principle of density functional theory, with the generalized approximation of the GGA gradient. We found that the ferromagnetic state of Ir2FeAl is more stable than the nonmagnetic configuration at their lattice parameters equilibrium. This result was confirmed by the calculation of the cohesive energy. The stability is asserted by the elastic constants and the conditions of the mechanical stability criterion. The band structure and the calculated densities of states (DOS) of this alloy show a semi-metallic behavior. The ferromagnetic performance of Ir2FeAl is confirmed by the total magnetic moment of 4.28 μ B , where its major contribution comes from Fe atoms. We estimated the Debye temperature of Ir2FeAl from the average speed of sound. This is the first quantitative theoretical prediction of the elastic properties of the Ir2FeAl compound, and it still awaits experimental confirmation. [ABSTRACT FROM AUTHOR]

In this paper, we have performed a study on the optical properties of single crystals ZnGa2S4 by method of density functional theory (DFT) and ellipsometry measurements. The calculated results for the real ε r and imaginary ε i parts of the dielectric function are compared with the measured experimental spectroscopic ellipsometry (SE) spectra in the 0.7–6.5 eV spectral region. Absorption coefficient-photon energy dependency revealed the existence of direct bandgap transitions with energy 3.5 eV. This result is very close to bandgap obtained from our theoretical calculation. [ABSTRACT FROM AUTHOR]

The optical properties of TiO2 are changed while doped with impurity atoms. This paper made a systematical calculation of the bandgap, the density-of-states (DOS), the optical properties for pure TiO2, and Bi-doped anatase TiO2 according to the first-principles plane wave ultrasoft pseudopotential method which is primarily based on the density functional theory (DFT). The calculation results exhibit that the bandgap decreased after doping, and the impurity energy level is produced into the bandgap of Bi-doped TiO2, which makes red-shift for the absorption band edge of Bi-doped TiO2 and the absorption is enhanced more in the visible light range. [ABSTRACT FROM AUTHOR]

The optical properties of TiO2 are changed while doped with impurity atoms. This paper made a systematical calculation of the bandgap, the density-of-states (DOS), the optical properties for pure TiO2, and Bi-doped anatase TiO2 according to the first-principles plane wave ultrasoft pseudopotential method which is primarily based on the density functional theory (DFT). The calculation results exhibit that the bandgap decreased after doping, and the impurity energy level is produced into the bandgap of Bi-doped TiO2, which makes red-shift for the absorption band edge of Bi-doped TiO2 and the absorption is enhanced more in the visible light range. [ABSTRACT FROM AUTHOR]

Diabetes, a chronic metabolic disease, has become a severe health problem worldwide. According to the latest data from the International Diabetes Federation (IDF), there were 537 million diabetic mellitus (DM) patients worldwide in 2021, expected to increase to 783 million by 2045. Over 90% of people with diabetes have type 2 diabetes, which is driven by socio-economic, demographic, environmental, and genetic factors. Diabetes is still a major global health issue, with prevalence rates rising all across the world. This not only imposes a significant burden on healthcare systems but also impacts the quality of life of affected individuals and their families. Therefore, there is a continuous high demand worldwide to develop novel, more effective, and easily affordable medications against diabetes. This paper illustrates the in-vitro antidiabetic activity and probable binding mechanism prediction of phytoconstituents of Allamanda cathartica against type 2 diabetes molecular targets. Through the application of bioactivity score prediction, molecular docking, and ADMET prediction approach, the potential and selective phytoconstituents with the highest binding affinity and lower toxicity were gained from the curated datasets. Further molecular dynamics simulations and DFT calculations were carried out to identify the favorable binding conformations when the top-scored phytoconstituents bind with the PPAR γ receptors compared to the rosiglitazone. Compound AC2 interacts with the PPAR γ proteins by forming seven hydrogen bonds with the amino acid residues Phe282, His449, Tyr327, His323, and Ser289. The ligand was bound to the protein during the simulation since none of the complex conformations was unstable, and no unfolding or folding occurred. Our results provided an approach to further design and optimize the natural product-inspired small druglike molecules as potential antidiabetic agents. This study highlighted that the phytoconstituents of Allamanda cathartica have antidiabetic potential through the binding of PPAR γ , α -amylase and α -glucosidase proteins that can be further explored for novel antidiabetic drug development. The ethyl acetate extract of A. cathartica displayed significant α -amylase inhibition compared to other fractions, reaching its peak inhibition at a concentration of 4 mg/mL. The organic extract prominently inhibited the enzyme α -glucosidase compared to other fractions, with maximal inhibition observed at a concentration of 4 mg/mL. Phytoconstituents of Allamanda cathartica have shown antidiabetic potential through the binding of PPAR γ , α -amylase, GLP-1 and α -glucosidase proteins Compound AC2 (1-deoxy-d-mannitol) interacts with the PPAR γ proteins through the formation of 7 hydrogen bonds with the residues Phe282, His449, Tyr327, His323 and Ser289, while compound AC31 (Phytol) forms two hydrogen bonds with His323 and Tyr473 amino acid residues. Compounds AC28 (Octanoic acid) show a better binding affinity for GLP-1 target protein. Compounds AC34 (Quercetin) and AC23 (Kaempferol) show excellent binding affinity for α -amylase and α -glucosidase enzymes. [ABSTRACT FROM AUTHOR]

In this paper, electronic properties of Janus MSX monolayers (M = Mo, W; X = Se or Te), including electron energy loss near edge structures (ELNES), as K and L2,3 edge spectra of sulfur atoms, have been calculated using a full potential scheme and the augmented plane wave plus local orbitals (APW+lo) method in the framework of density functional theory (DFT). Due to the lack of experimental results, the obtained spectra are compared with the corresponding spectra of MoS2 monolayer. The band structure analysis shows that the Janus MoSSe and WSSe monolayers are direct bandgap semiconductors, while the Janus MoSTe and WSTe monolayers are indirect bandgap semiconductors. In comparison to MoS2, the main structures of the K edge ELNES spectra of sulfur atoms in Janus monolayers occur at lower energies, due to the structural change and increased bond length. The relative reduction of intensities in the main structures predicts the possibility of reducing the number of partial densities of states (PDOS), that is, the reduced p PDOS for the K edge in the corresponding energy range. In the K (L2,3) edge ELNES spectra of the sulfur atom in Janus monolayers and MoS2 monolayers, the main structures are due to the electron transfer to the unoccupied px+py and pz states (3s of sulfur and 4d states of the transition metal). [ABSTRACT FROM AUTHOR]

This paper presents a simulation of the structural and optoelectronic properties of Scandium Arsenide (ScAs) and Aluminum Arsenide (AlAs) compounds. Theoretical modeling was performed using ab initio first-principles calculations, specifically the density functional theory (DFT), and the Mindlab numerical software. The software used two methods: the full-potential muffin-tin orbital method (FP-LMTO) and the full-potential plane-wave method (FP-LAPW). These two methods are employed to solve the Schrödinger equation. The exchange correlation effects have been computed using two different approximations: the generalized gradient approximation (GGA) and the local density approximation (LDA). Our findings indicate that the zinc blende structure (B3) is the stable phase, while the Wurtzite phase (B4) is metastable for the AlAs compound. On the other hand, the ScAs compound crystallizes in the NaCl phase (B1). The AlAs compounds undergo three phase transitions: B3→B4, B3→B2 and B3→B1. In contrast, ScAs does not undergo any transition. The obtained results for equilibrium energies, lattice parameters and gap energies are in closer agreement with the experimental and theoretical data. The AlAs compound exhibits a semiconducting character, while ScAs exhibits a semi-metallic character. Additionally, the refractive index of these two compounds is similar to that of silicon, which is crucial for their application in photovoltaic cells. [ABSTRACT FROM AUTHOR]

This research paper explores the structural, electronic, magnetic, elastic, dynamic, and thermoelectric properties of sp-based half-Heusler (HH) RbBaX (X = Si and Ge) compounds using density functional theory (DFT) and the full-potential linearized augmented plane wave (FP-LAPW) method within the WIEN2k software package. We evaluate the exchange correlation potential using two different approaches: The generalized gradient approximation (GGA) and the modified Becke–Johnson approach. We observe that RbBaX (X = Si and Ge) adopts a ferromagnetic configuration based on the analysis of total energy against volume. We establish that these alloys possess a genuine half-metallic character because of the full spin polarization observed at the Fermi level in their electronic spectrum. Both compounds under investigation have a total magnetic moment of 1.00 μ B, in agreement with the Slater–Pauling principle. The Born stability criteria for cubic structures and phonon dispersion patterns confirm the mechanical and dynamic stability of RbBaX (X = Si and Ge) alloys. The thermoelectric properties reveal a p-type semiconductor nature, characterized by significant positive Seebeck values. The thermoelectric figure of merit (ZT) calculated for both alloys at 300 K approaches unity, highlighting their remarkable thermoelectric efficiency. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical exploration of the electronic, structural, and mechanical attributes inherent in three rare-earth-free intermetallic compounds, namely, MnTi, MnZr, and MnHf. Employing density functional theory (DFT) calculations with the Implementation of projector augmented wave (PAW); our investigation adopts the supercell approach to meticulously determine the structural and mechanical properties of these materials. The findings reveal that MnTi and MnZr exhibit intrinsic ductility, positioning them as viable contenders for applications demanding high-strength structures. In contrast, MnHf demonstrates mechanical instability. This study provides promising insights into the mechanical characteristics of MnTi and MnZr, underscoring their potential as sustainable structural materials, given the abundance and non-toxic nature of their constituents. The research findings presented herein contribute to the understanding of rare-earth-free intermetallics, offering valuable information for applications in materials science and engineering. [ABSTRACT FROM AUTHOR]

In this paper, we present a drop model for integer and fractional quantum Hall effects (FQHE). We show that the two-dimensional electron gas breaks up into regions with filling factors ν = 1 and ν = 0 in the disk geometry, and the formation of drops with a finite number of electrons is possible. Sequences of filling fractions are constructed on the basis of experimental data. For all sequences, there are initial FQHE states, which correspond to a drop with five electrons. The remaining FQHE states are composite states of a drop with five electrons and one or more pairs of electrons. [ABSTRACT FROM AUTHOR]

The α -Fe(100)/Cr(100) interface has an important effect on the precipitation of the Cr-rich phase in ferritic stainless steel, and alloying elements affect the stability of the α -Fe(100)/Cr(100) interface. However, it is difficult to clearly understand the effect of alloying elements on the α -Fe(100)/Cr(100) interface behavior experimentally. Therefore, the first-principles calculation is employed to address this problem in this paper. First of all, the segregation behaviors of alloy elements (Mo, Nb, and Si) on the α -Fe(100)/Cr(100) interface were systematically investigated. And then, the effects of these alloying elements on the property of the α -Fe(100)/Cr(100) interface were studied. Based on the density functional theory, the work of adhesion (Wad), interfacial energy (γint), doping energy (E f ), and electronic properties of the α -Fe(100)/Cr(100) interface were analyzed. The results show that the body-centered α -Fe(100)/Cr(100) interface is constructed by using seven layers of α -Fe(100) and Cr(100) surface models. The Wad is 6.115 J.m − 2 , and the γint is −0.12 J.m − 2 . The doping atoms tend to segregate on the surface of α -Fe(100). When the Si atom doped in the interface, the Wad increases, and the γint reduces. The doping of the Si strengthens the bonding strength of the interface and promotes the nucleation of the Cr-rich phase. While the addition of Mo and Nb atoms decreases the Wad of α -Fe(100)/Cr(100) interface, increases the γint. The bonding strength of the interface is weakened and the nucleation of the Cr phase is inhibited. Based on this result, it is clearer to understand the effect of Mo, Nb, and Si atoms on the precipitation of the Cr-rich phase in ferritic stainless steel. [ABSTRACT FROM AUTHOR]

The present review is aimed to understand the Rashba and Dresselhaus effects from the first-principle calculations. A brief overview of first-principle density functional theory (DFT) and its global acceptance have been discussed. The discussions of the Rashba–Dresselhaus splittings, spin textures and understanding the effects from first-principle DFT calculations have been highlighted. Rashba and Dresselhaus effects have gained much attention in recent era for their highly promising applications in spintronics. In the presence of spin-orbit coupling and inherent non-centrosymmetry, while BiTeCl, TiS2Se, rhombohedral CsPbF3 and BiCoO3 compounds show large values of Rashba parameter ( α R) of ∼ 1. 9 0 , 1.10, 1.05 and 0.74 eVÅ, respectively, the single-layered semiconductor nanostructure InSb, rhombohedral BiFeO3 and Ag2BiO3 systems however depict promising values of Dresselhaus parameter ( α D) of ∼ 2. 2 0 , 0.50 and 0.15 eVÅ, respectively. The future of Rashba–Dresselhaus effects and their advancements in spintronics have also been enlightened in this paper. We believe that this study will not only help to understand the Rashba–Dresselhaus effects from first-principle calculations, but can also augment their applications in next generation spintronic devices. [ABSTRACT FROM AUTHOR]

In this paper, we have performed a study on the optical properties of single crystals ZnGa2S4 by method of density functional theory (DFT) and ellipsometry measurements. The calculated results for the real ε r and imaginary ε i parts of the dielectric function are compared with the measured experimental spectroscopic ellipsometry (SE) spectra in the 0.7–6.5 eV spectral region. Absorption coefficient-photon energy dependency revealed the existence of direct bandgap transitions with energy 3.5 eV. This result is very close to bandgap obtained from our theoretical calculation. [ABSTRACT FROM AUTHOR]

Based on density functional theory, structural, electronic, magneto-optic, and thermoelectric properties of RbCaN2 and RbCaO2, Heuslerene compounds have been calculated. These compounds have the ground state points with total magnetic moment of 1.0 μ B , which represents their ferromagnetic behavior. The RbCaN2 Heuslerene has the half-metallic nature and RbCaO2 case is a magnetic semiconductor. The Kerr angle of the RbCaN2 Heuslerene has two relatively peaks at the energies of 5.5 eV to 7.0 eV, but for the RbCaO2 compound, this diagram is wider in a larger energy range. Faraday angle peaks occurred at 6.2 eV and 6.8 eV for RbCaN2 and RbCaO2 compounds, which indicates the polarization of the light irradiated to them at these energies. It was observed that both compounds show high thermoelectric quality at temperatures higher than the room-temperature, and both compounds are suitable for power generator applications. [ABSTRACT FROM AUTHOR]

We constructed ZnO quantum dots (QDs) with a diameter of 1.2 nm of wurtzite structure, hydrogenated the surface and doped single Mn atoms using Zn-site substitution. We present an investigation of the structural and electronic properties of ZnO QDs of three doping sites: inner, intermediate and outer. Based on the density functional theory and the plane-wave pseudo potential method, the structural characteristics, charge distribution, conductivity and formation energy of doped ZnO QDs are analyzed. We obtained the effect of doping site depth on the properties above with the nearly optimal nanoparticle doping concentration (2.222%). The internal doping (inner and intermedium) configuration results in higher electrical conductivity and stronger bonds than the outer doping configuration. In particular, intermediate doping is highly efficient and valuable for obtaining Mn-doped ZnO nanoparticles with good structural and electronic properties. This study provides a theoretical reference for the survey of zero-dimensional dilute magnetic semiconductors. [ABSTRACT FROM AUTHOR]

Based on density functional theory (DFT), the structural and physical properties of NaCaZ (Z = N, P, As) half-Heusler (HH) semiconductor materials have been studied under pressure up to 20 GPa. The ground state results show that the NaCaZ are chemically stable in α -phase structure and exhibit semiconducting behavior with an indirect bandgap. The optical parameters like the real and imaginary components of complex dielectric function, the absorption coefficient and refractive index are investigated and discussed. The obtained results show that NaCaZ have low value of reflectivity and high absorption coefficient in low ultraviolet and visible regions and exhibit small changes under pressure. Pressure-based elastic constants and their derivative parameters show that NaCaZ are mechanically stable and have brittle nature. Above 10 GPa, NaCaP and NaCaAs have ductile nature. The phonon dispersions calculations with pressure show that NaCaN and NaCaP are dynamically stable, in contrast, NaCaAs is dynamically unstable at ambient pressure. Above 10 GPa, the studied compounds are dynamically stable. The mechanically, dynamically stable with low reflectivity and high absorption coefficient in the low ultraviolet and visible regions make these materials more promising as absorbers of solar cells, optoelectronic and 2D applications. [ABSTRACT FROM AUTHOR]

A rapid and enormously professional new-flanged 3,5-disubstituted triazole derivatives were synthesized by the one-pot five-component condensation reaction in the course of transesterification followed by the Biginelli/Click reaction in aqueous medium using magnetic CuFe2O4 NPs as heterogeneous catalyst beneath ultrasonic acceleration in aqueous medium. The synthesized 3,5-disubstituted triazole derivatives were finely characterized and the characterized desired target molecules were employed for the quantum chemical calculations for each reactant and product have been well thought-out using density functional theory. Furthermore, the molecular docking and ADMET revision of all the derivatives have been achieved as digestive enzyme and Cathepsin-B inhibitors and their connections with BSA to treat different diseases. [ABSTRACT FROM AUTHOR]

Theoretical studies for the bioactive nature of the molecule, 4-aminopyridine 4-aminopyridinium thiocyanate, performed by density function theory (DFT) studies and molecular docking, were simulated by a molecular electrostatic potential surface. Frontier molecular orbitals, molecular properties, and density of state of the spectrum were computed. On account of E HOMO and E LUMO showing their notable polarizability and number of reactivity parameters, they were calculated by DFT. The function of new scoring is to calculate the free energy change on binding in docking studies that exploit flexible ligands with macromolecular protein targets that have been evolved and tested. The protein β -catenin (1JPW) was docked and compared to the standard drug molecule doxorubicin in molecular docking studies. The obtained 4-aminopyridine 4-aminopyridinium crystals revealed the results that confirmed the studied compounds have significant anti-cancer properties. [ABSTRACT FROM AUTHOR]

In this study, we introduce a new protocol for the synthesis of tetracyclic acridone derivatives using a benzylation reaction under microwave irradiation. Compared to traditional approaches, our protocol is significantly more effective, takes far less time and is also in accordance with the principles of green chemistry. Under the solvent-free conditions, the benzylation reaction was performed between acridone (1 eq) and benzyl bromide (1 eq) in the presence of potassium carbonate (1.5 eq) under microwave irradiation. The reaction was completed within 3 min, resulting in higher yields of the products, up to 96%. It has been observed that the developed protocol is best suited for the N-benzylation of acridone with different benzyl halides. [ABSTRACT FROM AUTHOR]

Transition metal (Mn, Fe, Co and Ni)-doped tungsten oxides nanoparticles with magnetic properties may be applied in various catalysts such as water treatment as they are easy to be recycled. Structural, electronic and magnetic properties of TMn@W 1 2 O 3 6 (TM=Mn, Fe, Co and Ni, n=1–4) clusters have been calculated at PBE level. The results reveal that the centers of the TM 1 − 3 clusters are in accordance with that of the W 1 2 O 3 6 clusters while the TM4 clusters deviate obviously from the center of the W 1 2 O 3 6 cages. All TMn@W 1 2 O 3 6 clusters exhibit slightly less structural stability and obviously more chemical reactivity than the W 1 2 O 3 6 clusters. Mülliken spin densities of a TM atom embedded are almost kept except for the Ni@W 1 2 O 3 6 clusters. The spin densities of TMn clusters in the TM3@W 1 2 O 3 6 and TM4@W 1 2 O 3 6 clusters are offset. The magnetic TM modification strategy is helpful to design recyclable tungsten oxide catalysts. [ABSTRACT FROM AUTHOR]

The electronic band structure, density of states, optical absorption, phonon spectrum, stability, and thermodynamic properties of 1T'-phase RuOsSe2 hybrid monolayer were systematically studied using ab initio calculations based on Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT) within the generalized gradient approximation (GGA) and the HSE06 functional of hybrid correlation–exchange. Indirect bandgaps E g = 0. 6 8 eV and E g = 1. 2 3 eV were obtained within the calculation level GGA-PBE and HSE06. The investigation of optical absorption shows that the RuOsSe2 monolayer exhibits a significant absorption in the ultraviolet and visible regions of the electromagnetic spectrum. Thermodynamic potentials and specific heat at constant volume were calculated, of which dependence on the temperature is discussed. We predict a new RuOsSe2 monolayer from the 1T' phase that could potentially be synthesized for future electronic devices and bring potential technological applications. [ABSTRACT FROM AUTHOR]