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The contamination of water resources by industrialization is the biggest issue over the world and researchers are trying their best for the reduction of water pollution using cost-effective, non-toxic, and reusable photocatalysts. Therefore, this research article outlines the synthesis of manganese-doped iron oxide (Mn0.5Fe1.5O3) using the sol–gel method, and its subsequent combination with graphitic carbon nitride (Mn0.5Fe1.5O3@gCN) through ultrasonication. The resulting materials are investigated for their ability to degrade methylene blue and methyl red organic dyes through mineralization. The fabricated materials were confirmed by X-ray diffraction analysis (XRD), and FTIR spectroscopy, while the UV–visible approach was employed for the determination of optical spectra and bandgap of fabricated photocatalysts. The flat-band potential (0.75 and 0.77 eV) and the type (n-type) of the semiconducting oxides were examined by the Mott–Schottky curves. The prepared photocatalysts degraded 92% methylene blue and 91% methyl red under visible light irradiation for 70 min by pursuing a pseudo-first-order mechanism with rate constants 0.0381 and 0.0316 min−1, respectively. The maximum degradation was observed via Mn-Hem@gCN due to the penetration of the sheets of gCN that enhances the surface area of catalysts by trapping the photogenerated species for the photodegradation of wastewater contaminants. Highlights: Pristine and doped hematite were fabricated by auto-ignition route. The characterization was carried out by using XRD, FTIR, optical analysis, Mott–Schottky, and EIS. Methyl red and methylene blue were used as contaminants. Scavenging studies revealed that electrons were the active species participating in the degradation of contaminants. [ABSTRACT FROM AUTHOR]

Equilibrium molecular dynamics (EMD) simulations have been performed to investigate the structural analysis and thermal conductivity (λ) of semiconducting (8,0) and metallic (12,0) zigzag single-walled carbon nanotubes (SWCNTs) for varying ±γ(%) strains. For the first time, the present outcomes provide valuable insights into the relationship between the structural properties of zigzag SWCNTs and corresponding thermal behavior, which is essential for the development of high-performance nanocomposites. The radial distribution function (RDF) has been employed to assess the buckling and deformation understandings of the (8,0) and (12,0) SWCNTs for a wide range of temperature T(K) and varying ±γ(%) strains. The visualization of SWCNTs shows that the earlier buckling and deformation processes are observed for semiconducting SWCNTs as compared to metallic SWCNTs for high T(K) and it also evident through an abrupt increase in RDF peaks. The RDF and visualization analyses demonstrate that the (8,0) SWCNTs can more tunable under compressive than tensile strains, however, the (12,0) zigzag SWCNTs indicate an opposite trend and may tolerate more tensile than compressive strains. Investigations show that the tunable domain of ±γ(%) strains decreases from (-10%≤ γ ≤+19%) to (-5%≤ γ ≤+10%) for (8,0) SWCNTs and the buckling process shifts to lower ±γ(%) for (12,0) SWCNTs with increasing T(K). For intermediate-high T(K), the λ(T) of (12,0) SWCNTs is high but the (8,0) SWCNTs show certainly high λ(T) for low T(K). The present λ(T, ±γ) data are in reasonable agreement with parts of previous NEMD, GK-HNEMD data and experimental investigations with simulation results generally under predicting the λ(T, ±γ) by the ∼1% to ∼20%, regardless of the ±γ(%) strains, depending on T(K). Our simulation data significantly expand the strain range to -10% ≤ γ ≤ +19% for both zigzag SWCNTs, depending on temperature T(K). This extension of the range aims to establish a tunable regime and delve into the intrinsic characteristics of zigzag SWCNTs, building upon previous work. [ABSTRACT FROM AUTHOR]

Hybrid supercapacitors are energy storage technology offering higher power and energy density as compared to capacitors and batteries. Cobalt-doped manganese oxide (Co@MnO2) was synthesized using an easy and affordable sol–gel process and measured the electrochemical properties. A value of the specific capacity of 1141.42 Cg−1 was obtained which was larger in comparison to the reference sample (MnO2 = 673.79 Cg−1). The value of the specific capacitance was achieved 1902 Fg−1. To design a hybrid supercapacitor device, Co@MnO2 was used as the positive electrode and the activated carbon was employed as the negative electrode in two-electrode assembly. According to calculations, the measured value of the specific capacitance of Co@MnO2 was 713.25 Fg−1. The charge storage mechanism is supported with the help of Randles–Ševčík and Dunn's models. The estimated value of energy and power densities were 3200 Wh kg−1 and 24 Wkg−1, respectively. The stability of this device was checked by putting it to 1000 charging and discharging cycles, and it retained 86% of its initial capacity. Our result provides a platform for enhancing the functionality of energy storage systems. [ABSTRACT FROM AUTHOR]

Supercapattery is an energy storage device which shows high power and energy densities compared to supercapacitors and batteries. A simple and cost‐effective sol‐gel method was used to synthesize the aluminium‐doped cobalt oxide (Al‐Co3O4). The structural, morphological and composition analyses were investigated using X‐ray diffraction (XRD), scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS). Further, Brunauer‐Emmett‐Teller (BET) calculations were performed, which showed an enhancement in surface area. The specific capacity of the Al‐doped sample was increased up to 708 C/g compared to the reference sample (Co3O4=420 C/g). A supercapattery device was designed by using the activated carbon as a negative electrode and the Al‐Co3O4 as the positive electrode in two electrode assemblies. The estimated value of the specific capacity of Al‐Co3O4 was 189 C/g. Furthermore, the obtained energy and power density values were 42 Wh/kg and 2080 W/kg, respectively. To investigate the stability, this device was subjected to 5000 charging/discharging cycles that maintained 90 % of its initial capacity. Our findings provide a foundation for improving the performance of energy storage devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) thermal conductivity of strongly coupled dusty plasmas, taking into account the polarization effect of dust particles, has been investigated through homogenous nonequilibrium molecular dynamics (HNEMD) simulations. Thermal conductivity (λ), in the limit of varying polarization values, is reported over a appropriate domain of plasma states (Γ, κ), coupling (dipole–dipole) factor (Γd) and constant external force field (F*). New results of polarized λ show that the effect of polarization definitely decreases the λ at low-intermediate to large Γ where it was earlier shown to have high value of λ without considering polarization effects. The obtained results for polarized λ decrease with increasing system size (N) and Coulomb coupling (Γ) at varying polarization values (Γd) but within statistical limits, however, polarized λ becomes nearly constant at higher N. The simple temperature scaling law has been checked for variations of normalized (Einstein) thermal conductivity with polarization effects. The current HNEMD outcomes under varying polarization values and constant force (external) field strength are reasonable well matched with earlier known simulation data of equilibrium, nonequilibrium molecular dynamics simulations and experimental data. It has been revealed that the present HNEMD simulations extended the range of polarization values up to 1 ≤ Γd ≤ 150 in order to maintain the range of linearity at F* (≡ 0.2) and to illuminate the nature of polarized system of 2D strongly coupled dusty plasmas. [ABSTRACT FROM AUTHOR]

The space-time correlation function has been obtained in strongly coupled dusty plasmas (SCDPs) using equilibrium molecular dynamics (EMD) simulations. The simulated results for three-dimensional (3D) SCDPs with suitable normalization are computed over a wide domain of plasma parameters (Γ, κ) in a microcanonical ensemble. The EMD simulations indicate that different modes of propagated wave in SCDPs are analyzed for four different values of wave number (k). New investigations of normalized longitudinal current correlation function CL(k, t) show that the amplitude of oscillation and frequency of propagated modes increase with an increase in k. The obtained results for longitudinal modes of oscillation indicate that the dust particles remain in damping behavior at the low Γ, damped oscillation with decreasing amplitude inside decaying exponential envelope at intermediate Г, and sinusoidal oscillation at high Г, depending on κ. The system size (N) does not significantly affect the propagated modes of oscillation, while the periodic oscillation shifts toward higher Γ with increasing N and κ. The computations show that normalized longitudinal CL(k, t) current correlation particularly depend on Coulomb coupling (Γ), Debye screening (κ), and wave number (k). In our simulations, the frequency and the amplitude of oscillation of the dust particles decrease with an increment of κ and system size (N), but the frequency increases and the amplitude decreases with increasing Γ, as expected. It has been demonstrated that the EMD method is used to study the different propagated modes in dusty plasma systems and can be used to predict the damping behavior, damped oscillation, and periodic phenomena in 3D strongly coupled SCDPs. [ABSTRACT FROM AUTHOR]

Inverse perovskites are the counterparts to the largest family of crystalline perovskite materials and have attracted significant research interest because of their unconventional physical and chemical properties. Perovskite materials have been studied widely; however, less attention has been paid to their counterparts (inverse perovskites). In the present study, we report on the structural, electronic, elastic, mechanical, magnetic and thermodynamic properties of unexplored Rh-based XCRh3 (X = Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Zr, Nb, Mo, Tc, Ru, Pd, Ag) inverse perovskites. The first-principles density functional theory-based linearized augmented plane wave method as implemented in the Wien2k package with the generalized gradient approximation was employed for the investigation of the physical properties. The computed formation energies showed that the majority of these materials comparatively favor the ferromagnetic phase over the non-magnetic phase. Amongst the studied XCRh3, X = Ti-, V-, Cr-, Mn-, Zn- and Zr-based materials comprise negative formation energies confirming the energetic stability. All the compounds other than NbCRh3 and MoCRh3 were found mechanically stable. Spin-projected electronic properties of XCRh3 revealed the conducting features in both spin versions. The large magnetic moments per unit cell (> 3μB) of CrCRh3, MnCRh3, FeCRh3 and TcCRh3 were observed with dominant contribution from X-atoms. Mechanical anisotropy and other bulk mechanical parameters are elaborated and discussed in detail. The thermodynamic properties including specific heat capacity, thermal expansion coefficient and Debye temperature are scrutinized at different temperature and pressure ranges. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) strongly coupled nonideal plasma systems (SC-NIPSs) are modeled using equilibrium molecular dynamics (EMD) simulations. The dynamical structure factor (DSF) has been investigated under influence of varying wave vectors (k = 2π/L) at high Debye screening (κ) and varying Coulomb couplings (Γ) from nonideal phase to strongly coupled phase. New outcomes of dust DSF S(k,ω) indicate that the frequency of oscillation increases and amplitude decreases with an increase in Γ, respectively, for the SC-NIPSs. The present work shows that the amplitude of dust DSF slightly increases with increasing κ and N, and it also depends on variation of wave vectors. Our investigations demonstrate that the amplitude of oscillation of the dust DSF is changed and shape of spectrum switches from damped oscillation mode to sinusoidal mode with an increase in Γ. These modes of oscillation of dust DSF S(k,ω) shift to higher Γ with increasing κ and N. It has been revealed that the fluctuating density S(k,ω) of dust more oscillates at high Γ and midway value of κ, but this oscillation is less pronounced at high N and κ. The reported simulation data are found to have more precise and well-organized than that of earlier known numerical outcomes and it provides reasonable EMD outcomes with suitable varying N at high screening and large values of Γ than earlier numerical results. [ABSTRACT FROM AUTHOR]

The aim of this research work was to assess the impact of front and rear grid metallization pattern on the performance of silicon solar cells. We have investigated the effect of front grid metallization design and geometry on the open-circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and efficiency (ŋ) of back surface field (BSF) silicon solar cells by using Griddler 2.5 simulation program. We simulated a design of H-pattern front and rear metal grids onto the silicon wafers. For this purpose we used different number of metal fingers ranging from 80 to 120 having width of 60 μm and different number of busbars ranging from 1 to 5 busbars on the front and rear side of solar cells for optimization study. We have also calculated the efficiency and fill factor at different values of front contact resistance ranging from (0.1–100) mohm-cm2, front and rare layer sheet resistances ranging from (60–110) ohm/sq and different edge gaps. We obtained the maximum efficiency and fill factor, when the front and rare contact resistances were taken as same in silicon solar cells simulation. We have designed an optimized silicon solar cell with 115 number of fingers, 4 busbars, front and rare contact resistance of 0.1 mohm-cm2 and front and rare layer sheet resistance of 60 ohm/sq. In this way we were able to optimize the silicon solar cell having efficiency and fill factor of 19.49 and 81.36 % respectively, for our best optimized silicon solar cell. [ABSTRACT FROM AUTHOR]

Cadmium ferrites belong to normal spinel ferrites, and they exhibit interesting electrical, magnetic, and optical properties. The pure and cerium-doped cadmium ferrites CdFe2−xCexO4 (x = 0.0, 0.125, 0.250, 0.375, 0.5) were synthesized by a chemical co-precipitating technique using sodium hydroxide as a co-precipitating agent. The structures and phase purity of fabricated nanomaterials were analyzed by X-ray diffraction (XRD). The crystallite size for all the prepared nanomaterials was in the range of 28–46 nm. The lattice constant and unit cell volume were found to decrease with the increasing concentration of Cerium, which was confirmed by the peak shift in the XRD pattern. The X-ray density for all nano ferrites increased with the enhancement of cerium composition. The resistivity of the nanomaterials has random behavior with the enhancement of cerium composition for a temperature, but the value of resistivity at x = 0.125 has the lowest value and at x = 0.375 has the highest value for almost all temperatures. For specific concentrations, a decreasing trend of resistivity of fabricated materials was found with an increment of temperature. The activation energies were also calculated, and it increased for x = 0.125 and then decreased for all the nanomaterials. For the confirmation of the M–O bonds, FTIR analysis of all the nano ferrites was also performed. The analysis shows a higher frequency absorption band in the range of 531.24–534.84 cm−1. This absorption band confirms that metal oxides are formed in all the synthesized nanoparticles. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenide (TMD) material-based van der Waals (vdW) heterostructures have gained huge attention due to their superior capabilities and multiple functionalities in electronics and optoelectronic devices. In this work, a gallium telluride/hafnium selenide (GaTe/HfSe2) vdW heterostructure with excellent ohmic contacts is studied. A high gate-modulated rectification ratio (RR) of 6.3 × 105 is attained. Furthermore, the photovoltaic measurement is performed under the illumination of laser light of a wavelength of 532 nm and various powers (20–100 μW). Its rise and decay times (18 μs & 24 μs) are superior among those of various reported vdW heterostructures. The photoresponsivity of GaTe/HfSe2 is enhanced significantly up to with an external quantum efficiency (EQE = 54%) as compared to those of the various reported vdW heterostructures. Such TMD based heterostructure devices would improve the energy harvesting needs along with the multifunctional logic operations. [ABSTRACT FROM AUTHOR]

In this research work we have synthesized copper sulfide (Cu2−xS) nanostructures by the hydrothermal method. The post-sulfurization was performed by using tube furnace to reduce sulfur deficiency and to minimize impurities present in the crystal-lattice. The samples were synthesized by various pH values of precursor solution. The samples were characterized by XRD, RAMAN spectroscopy, SEM, Hall measurements and Seebeck effect. XRD analysis revealed the formation of hexagonal covellite (CuS) and chalcocite (Cu2S) phases of copper sulfide. Despite these phases XRD data also showed the dominating hexagonal digenite (Cu1.8S) phase of copper sulfide. We observed a decreasing trend in average crystalline size with the increasing pH values of the samples from the XRD data. We have found maximum average crystalline size of 39.1679 nm at pH value of 4. The formation of LO mode of hexagonal covellite phase of copper sulfide was observed from RAMAN analysis. The SEM images revealed the formation of flower-like nanostructures at the lowest pH value. It strengthened our argument that the crystallinity of nanostructures is inversely proportional to the pH value. We have achieved maximum values of Seebeck coefficient and conductivity at room temperature as 73.920 µV/K and 0.909 S/cm, respectively. The Seebeck coefficient and conductivity graphs showed an increasing trend due to the energy filtering effect in mesoporous structure. The maximum value of power factor was 4.91 × 10–7 Wm−1 K−2. [ABSTRACT FROM AUTHOR]

Single-phase bismuth ferrite (BFO) nanostructure is an intriguing contender in ferrite materials due to high magnetization and polarization at room temperature. In this study, the structural, electrical, magnetic, dielectric, and photovoltaic properties of BFO nanostructure are presented under different environments. To inspect the impact of annealing environments on structure and morphology, the prepared BFO samples are characterized by X-Ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM). Further, we examined the annealing effect on magnetic, electric, dielectric properties, and power conversion efficiency (PCE). The leakage current is decreased up to 4 times as compared to the reference sample, by reducing the dielectric loss. Besides, a BFO/ZnO heterostructure device is fabricated by using the graphene/ITO hybrid electrode to investigate the photovoltaic characteristics. The PCE is improved from 4.2 to 6.1% by using the hybrid transparent electrode composed by graphene and ITO and annealing in an oxygen atmosphere. Besides, the external quantum efficiency (EQE) with responsivity (R) of the heterostructure device is also enhanced. So, the perfection in the vital parameter of BFO nanoparticles evidently emphasize the prominence of the annealing atmosphere in BFO nanoparticles applications. [ABSTRACT FROM AUTHOR]

A series of Cu-Co-substituted manganese ferrites (Mn1-xCuxFe2-yCoyO4; x = 0.0–0.1, y = 0.00–0.25) were synthesized via microemulsion method. The values of structural parameters, i.e., lattice constant and crystallite size, were increased with the inclusion of Co and Cu ions. FTIR studies revealed first band at 400–500 cm−1 and second band at 561–588 cm−1. The values of dielectric parameters have been increased with the increase of Cu and Co concentrations. The magnetic parameters, i.e., saturation magnetization (Ms), coercivity (Hc), and remanence (Mr), have been investigated from M-H loops. The values of Ms and Mr were observed to increase from 5.00 to 36.02 emu/g and from 4.6 to 13.2 emu/g, respectively. The value of coercivity had been decreased from 466 to 261 Oe. The increase in saturation magnetization as well as decrease in dielectric losses proposed that synthesized nanoferrites may be potential candidates for high frequency and microwave applications. [ABSTRACT FROM AUTHOR]

A systematic investigation on structural, electronic, elastic, mechanical and optical properties of novel 1:1 stoichiometric rare-earth HoX (X = Pd, Ag and Cd) intermetallic compounds has been made viaab-initio density functional theory-based linearized augmented plane wave method as coded in wien2k. An outline of local density approximation and generalized gradient approximation have been employed. Structural optimization established the stable CsCl-type cubic structure of HoX (X = Pd , Ag and Cd) compounds. The determined crystal structure stability, compressibility and fracture strength of compounds are enhanced with X in the order HoPd > HoAg > HoCd . The interlacing electron dispersion curves at Fermi-level in band structure and density of states substantiate the metallic nature of compounds. The splitting gap between the lower and upper valence bands monotonously becomes narrower with the substitution of heavier core-element (Pd → Ag → Cd) . The mechanical constants i.e., bulk modulus (B), Young’s modulus (E), shear modulus ( G H ), Pugh’s ratio (B / G H) , Poisson’s ratio (v) and anisotropic factor (A) have been calculated to corroborate the mechanical properties of compounds. The cationic nature of Ho-atoms and anionic nature of X-atoms has been evaluated through the effective charge (Q ∗ ) computations. The observed peaks in the low energy region of optical conductivity spectra attribute the intra-band, while the high energy structures are associated with inter-band transitions in HoX (X = Pd, Ag and Cd) compounds. The bond order calculations demonstrate the highest strength of HoCd compound among the herein studied compounds. [ABSTRACT FROM AUTHOR]

We have compared the multiferroic behavior in different-sized BiFeO nanoparticles (11-29 nm) prepared by a solution evaporation method. The effects of oxygen vacancies on the behavior of phase pure BiFeO have been studied for particles prepared under two different annealing environments, air and oxygen. We find that BiFeO nanoparticles show weak ferromagnetism at room temperature which increases with decreasing particle size. However, the effects are determined not to be related to the presence of more oxygen vacancies, since oxygen annealing increases the magnetic moment in this system. In dielectric studies, we observe clear evidence for magnetoelectric coupling with the imaginary part of dielectric constant exhibiting a clear anomaly around the magnetic transition temperature ( T ~ 560 K). In high temperature resistivity measurements insulating and activated resistivity behavior is observed with the activation energies being lower for T < T. The increased ferromagnetism in smaller particles is explained in terms of suppression of the antiferromagnetic spin spiral whereas oxygen annealing actually leads in our case to an improvement of the crystallinity. [ABSTRACT FROM AUTHOR]