Energy Dispersive X-ray Spectroscopy Measurements Research Articles

Synthesis of ZnO and ZnO/Ag fine particles by plasma-assisted inkjet processing

Zinc oxide (ZnO) and its composite particles with controlled sizes, shapes, compositions, and physical and chemical properties are required for a wide variety of applications. In this study, we report a simple method for synthesising ZnO and ZnO/Ag composite particles via atmospheric-pressure plasma processing using inkjet droplets. Depending on the initial solution concentration, ZnO particles containing voids, with average sizes ranging from submicrons to several microns can be synthesised. Energy dispersive x-ray spectroscopy measurements of the synthesised ZnO/Ag particles suggest that the molar ratio of Ag to Zn in the initial solution was retained in the synthesised particles. A high surface-enhanced Raman scattering effect was observed in the particles synthesised from the solution with an Ag molar ratio of 50% to the total solute. The proposed method enables the synthesis of ZnO particles of various sizes, microstructures, compositions and optical properties with relatively narrow size distributions.

Facile synthesis and optimization of graphene oxide reduction by annealing in hydrazine vapour in ambient air for potential application in perovskite solar cells

Graphene oxide (GO) was synthesized from graphite via a modified Hummer's method, followed by thermal and chemical reductions to produce reduced graphene oxide (RGO) samples at various temperatures. A suite of characterization techniques including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), UV-Visible Spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Hall effect measurements were employed to assess the structural, morphological, optical, and electrical properties of the samples. FTIR analysis confirmed the successful functionalization of graphite to GO and subsequent reduction to reduced graphene oxide, with peak intensities decreasing as the reduction temperature increased. UV-visible spectroscopy of GO showed a maximum absorption at 235 nm which confirmed the synthesis of GO while the reduction revealed a notable red shift in absorption peaks with increasing annealing temperature, and that signified a reduction in bandgap. XRD analyses demonstrated the removal of oxygen functional groups. The X-ray diffraction (XRD) analysis of GO showed diffraction at 2θ = 10.74° which revealed a fully oxidized graphene oxide with oxygen-containing functional groups, and hence an increase in interlayer spacing (d002) from 3.341 Å (graphite) to 8.228 Å (GO). Upon reduction, there is a gradual decrease in d002 from 8.228 Å (GO) to 3.387 Å (HRGO300), suggesting the gradual removal of intercalated oxygen molecules, and hence the gradual restoration of sp2 hybridisation in graphene. The EDS analysis revealed an increase in the carbon-to-oxygen (C/O) ratio from 1.78 in GO to 2.75 in HRGO300 as the annealing temperature for the reduction process increased which further confirmed the removal of oxygen functional groups. The Hall effect data showed hole mobility of 4.634 x101 (GO), 4.831 x101 (HRGO200), and 5.462 x100 (HRGO300) with conductivities of 8.985 x10-5 (GO), 1.087 x100 (HRGO200) and 1.791 x101 1/Ω cm, suggesting an increase in conductivity as the annealing temperature increased as revealed in the EDS. Out of the three samples identified as hole transport materials, the sample HRGO300 with the highest C/O ratio of 2.75 has the highest conductivity, and hence most suitable for application as hole transport material in perovskite solar cell.

Orientation Relationship of the Intergrowth Al13Fe3 and Al13Fe4 Intermetallics Determined by Single-Crystal X-ray Diffraction

In the Al-Fe binary system, the Al13Fe3 phase as well as the Al13Fe4 phase has similar icosahedral building blocks like those appearing in quasicrystals. Therefore, it is of vital importance to clarify the formation process of these two phases. Coexistence of the Al13Fe3 and Al13Fe4 phases was discovered from the educts obtained with a nominal atomic ratio of Al/Fe of 9:2 by high-pressure sintering for the first time. Firstly, single crystal X-ray diffraction (SXRD) combined with a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) measurement capabilities were adopted to determine the detailed crystal structures of both phases, which were sharply refined with regard to Al13Fe3 and Al13Fe4. Secondly, the orientation relationship between Al13Fe3 and Al13Fe4 was directly deduced from the SXRD datasets and the coexistence structure model was consequently constructed. Finally, seven pairs of parallel atomic planes and their unique orientation relations were determined from the reconstructed reciprocal space precession images. In addition, the real space structure model of the intergrowth crystal along with one kind of interfacial atomic structure were constructed from the determined orientation relations between two phases.

Development of an in situ alloying method for high-performance welding processes to achieve an LTT effect by local modification of the alloy content

One possible option for increasing the fatigue strength of welded joints is the use of so-called low transformation temperature (LTT) alloys. The aim is to introduce residual compressive stresses into the weld to counteract crack initiation and propagation. Until now, there has been no application of an LTT effect to high-performance welding processes such as the laser beam submerged arc hybrid welding process (LUPuS hybrid). First, the LUPuS hybrid single-wire process was further developed into the LUPuS tandem hybrid process. This makes it possible to equip the two submerged arc welding torches with different commercially available filler wires. The aim of the work is to further develop the LUPuS tandem hybrid welding process to enable the use of the LTT effect. The in situ alloying process for obtaining the LTT effect from commercially available material combinations was extended to the two-wire process. The alloy obtained was investigated by means of energy dispersive x-ray spectroscopy and hardness measurements and the influence on residual stresses was determined by the borehole method supported by electronic speckle pattern interferometry.

Orientation Relationship of Intergrowth Al2Fe and Al5Fe2 Intermetallics Determined by Single-Crystal X-ray Diffraction

Although the Al2Fe phase has similar decagonal-like atomic arrangements as that of the orthorhombic Al5Fe2 phase, no evidence for intergrowth samples of Al2Fe and Al5Fe2 has been reported. In the present work, the co-existence of Al2Fe and Al5Fe2 phases has been discovered from the educts obtained with a nominal atomic ratio of Al:Fe of 2:1 by arc melting. First, single-crystal X-ray diffraction (SXRD) as well as scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) measurements have been utilized to determine the exact crystal structures of both phases, which are refined to be Al12.48Fe6.52 and Al5.72Fe2, respectively. Second, the orientation relationship between Al2Fe and Al5Fe2 has been directly deduced from the SXRD data sets, and the co-existence structure model has been constructed. Finally, four pairs of parallel atomic planes and their unique orientation relations have been determined from the reconstructed reciprocal-space precession images of (0kl), (h0l), and (hk0) layers. In addition, one kind of interface atomic structure model is constructed by the orientation relations between two phases, correspondingly.

Impurities related micro-defects in GaSb crystal grown by LEC method

The epitaxial growth of devices based on gallium antimonide (GaSb) is negatively impacted by defects related to impurities in the crystal. Liquid encapsulated czochralski (LEC) technology was used to grow 2-inch Te-doped GaSb (100) single crystal ingots, which were then processed into polished wafers in order to investigate the origins and consequences of defects related to impurities. Polished GaSb wafers were found to have surface micro-defects. Energy dispersive x-ray spectroscopy (EDAX) and scanning electron microscopy (SEM) measurements indicate that the micro-defects are associated with carbon and oxygen impurities. Glow discharge mass spectrometry (GDMS) is used to identify the origins of carbon and oxygen impurities. Based on the findings, an optimization process was developed to enhance the crystal quality, and a micro-defect-free GaSb single crystal was produced.

The growth of Ge and direct bandgap Ge1-xSnx on GaAs (001) by molecular beam epitaxy.

Germanium tin (GeSn) is a tuneable narrow bandgap material, which has shown remarkable promise for the industry of near- and mid-infrared technologies for high efficiency photodetectors and laser devices. Its synthesis is challenged by the lattice mismatch between the GeSn alloy and the substrate on which it is grown, sensitively affecting its crystalline and optical qualities. In this article, we investigate the growth of Ge and GeSn on GaAs (001) substrates using two different buffer layers consisting of Ge/GaAs and Ge/AlAs via molecular beam epitaxy. The quality of the Ge layers was compared using X-ray diffraction, atomic force microscopy, reflection high-energy electron diffraction, and photoluminescence. The characterization techniques demonstrate high-quality Ge layers, including atomic steps, when grown on either GaAs or AlAs at a growth temperature between 500-600 °C. The photoluminescence from the Ge layers was similar in relative intensity and linewidth to that of bulk Ge. The Ge growth was followed by the growth of GeSn using a Sn composition gradient and substrate gradient approach to achieve GeSn films with 9 to 10% Sn composition. Characterization of the GeSn films also indicates high-quality gradients based on X-ray diffraction, photoluminescence, and energy-dispersive X-ray spectroscopy measurements. Finally, we were able to demonstrate temperature-dependent PL results showing that for the growth on Ge/GaAs buffer, the direct transition has shifted past the indirect transition to a longer wavelength/lower energy suggesting a direct bandgap GeSn material.

Denary High-Entropy Oxide Nanoparticles Synthesized by a Continuous Supercritical Hydrothermal Flow Process.

High-entropy oxide nanoparticles (HEO NPs) have been intensively studied because of their attractive properties, such as high stability and enhanced catalytic activity. In this work, for the first time, denary HEO NPs were successfully synthesized using a continuous supercritical hydrothermal flow process without calcination. Interestingly, this process allows the formation of HEO NPs on the order of seconds at a relatively lower temperature. The synthesized HEO NPs contained 10 metal elements, La, Ca, Sr, Ba, Fe, Mn, Co, Ru, Pd, and Ir, and had a perovskite-type structure. Atomic-resolution high-angle annular dark-field scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy measurements revealed homogeneous dispersion of the 10 metal elements. The obtained HEO NPs also exhibited a higher catalytic activity for the CO oxidation reaction than that of the LaFeO3 NPs.

A novel primitive cubic Al-Fe-Si phase in an Al-0.5Fe-0.2Si (wt.%) alloy

We report the identification of a new ternary Al-Fe-Si phase synthesized by arc-melting. Energy dispersive X-ray spectroscopy measurements show an homogeneous chemical distribution within the intermetallic grain with an overall stoichiometry equal to Al81.0Fe13.6Si5.4 (at.%). Atomically resolved High-Angle Annular Dark Field images collected along the [001] zone-axis are consistent with a cubic structure with an unit cell parameter close to 8.9 Å. Using microdiffraction analysis, it was possible to explore the zero-order Laue zone (ZOLZ) and first-order Laue zone (FOLZ) . This electron diffraction characterization leads to the conclusion that the Al81.0Fe13.6Si5.4 (at.%) crystallizes in the Pm3̄ space group.

Evaluation of structural and corrosion behavior of chitosan/silver coating on Ti6Al4V/TiO2 nanotubular surface

Materials used in biomedical applications must have good bulk and surface properties. The main goal of this work is to create a multifunctional surface based on chitosan-coated Ag-loaded TiO2 nanotubes to assess their capacity in the corrosion resistance property. In the first phase, Ag-loaded TiO2 nanotubular surfaces with different weight percentages of silver were fabricated at a constant voltage of 2 V under varied time durations of 1 min, 2 min, and 3 min. In the second phase, cathodic electrophoretic deposition (EPD) was used to coat the samples with chitosan by applying 10 V for 5 min as a constant process parameter for coating all the samples. The composition and morphology features of in-house fabricated Ag-loaded TiO2 nanotubular surface with chitosan were studied by different techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), and Contact angle measurement. The corrosion resistance of the coated samples was assessed by using OCP, PDP, and EIS techniques. The results evidenced that chitosan-coated Ag-loaded (2 V 2 min) TiO2 nanotubular surface (TNT-Ag2.2/Ch) showed the best performance as a coating system when compared to an uncoated surface. Also, electrochemical corrosion studies showed better corrosion resistance for this coated sample. In this context, the chitosan that has been deposited serves as a protective barrier, facilitating the penetration of the physiological solution into the underlying metal surface. Overall, the TNT-Ag2.2/Ch coated sample showed 5 times better results when compared with icorr values. Finally, the newly developed chitosan-coated Ag-loaded TiO2 nanotubular surface improve the corrosion resistance of the polished Ti6Al4V alloy.

Glass/steel/clay interactions in a simulated radioactive waste geological disposal system

Deep geological storage is the accepted solution for the final disposal of high-level radioactive waste therefore, it is necessary to study the host rock of the planned Hungarian waste repository and the materials involved in the engineered barriers. The main goal was to understand the characteristics and stability of the glass/steel/claystone system, from the structural properties of the vitrified waste (borosilicate glasses) to the clay response in the repository. Repository conditions were applied during the experiments to understand the chemical evolution of the system. A triplicate setup was kept at 80 °C for 3, 7 and 12 months and post-mortem characterization was performed. No alteration products were observed with scanning electron microscopy energy dispersive X-ray spectroscopy measurements on the surface of the glass and Fe or in the clay after the end of the experimental period. Based on the elemental analysis of the liquid phase, the released amount of B, K, Si and Na increased, while that of Ca and Mg decreased compared to the baseline. The concentrations of Cl− and SO42− did not change significantly. Ca- and Mg-silicate precipitation was observed by X-ray photoelectron spectroscopy at the surface range of the borosilicate glasses because of the synthetic porewater treatment.

Dual role of CoO and electron beam irradiation in enhancement the transport properties of borate glasses

The synthesis of lithium borate cadmium glasses doped with cobalt oxide (CoO) (LiBCdCo) was achieved using the traditional melt-quench process. The chemical composition of the glasses was determined to be 12 % Li2O – 5 % CdO – (83-z)% B2O3, where z represents the mol% of CoO and ranges from 0.0 to 2. Various experimental approaches, such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, FTIR and electrical measurements, were employed to investigate the physical, structural, and electrical properties. XRD patterns obtained from the manufactured glass specimens revealed their amorphous nature. The EDX analysis provides insight into the exact chemical composition of the materials in their prepared form. Raman spectroscopy and FTIR analysis have been employed to verify the disparity in the chemical bonds present in lithium borate cadmium glasses, both in their undoped state and when doped with 2 % CoO. The study observed a decrease in density and oxygen packing density as the molar ratios of the modifier oxides in the produced glasses increased. The present study investigates the electrical conductivity and dielectric properties of the glass samples manufactured, focusing on the influence of electron beam irradiation (E.B.). The investigation revealed that the samples exhibited greater effects when exposed to higher doses (100 kGy) of electron beam irradiation. This can be attributed to the increased occurrence of defects, specifically the formation of non-bridging oxygen species (NBOs). The ac-conductivity measurements indicate that the correlated barrier hopping (CBH) mechanism is the most suitable explanation for the ac-conduction behavior observed. This mechanism involves the electron conduction in the CoO-doped glass samples through the hopping of electrons between relaxation sites. This conduction process is facilitated by the conversion of BO3 units into BO4 units and the reduction of cobalt ions from Co+2 to Co+3.

Synthesis and electrochemical properties of -Fe2O3 particles for energy storage devices

In this study, we fabricated α-Fe2O3 materials via a facile hydrothermal route to use as the active material for iron-based battery anode. The particle size of α-Fe2O3 is in a range of a few hundreds of nanometers to a few micrometers. The structural characteristics and particle size of the synthesized iron oxides were studied via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical behavior of iron oxide electrode was investigated by cyclic voltammetry (CV). The distribution of iron species was observed by Energy dispersive X-ray spectroscopy (EDS) measurement. Carbon was used as additive to improve the conductivity of α-Fe2O3/C composite electrode. The electrochemical measurements revealed that the prepared α-Fe2O3 particles provided the good cyclability. The EDS showed that iron species were dispersed on the carbon surface during discharge-discharge through the electrochemical dissolution-deposition process of iron.

Synthesis, analysis, and characterization of structural and optical properties of thermally evaporated chalcogenide a-Cu-Zn-Ge-Se thin films

Thin novel amorphous thin Cu25-x(ZnGe)25-xSe50+2x (CZGSe) films (0.0≤x≤10.0at.%) are synthesized by thermal evaporation deposition technique under the vacuum of ≈ 10−4 Pa with almost 500 nm thickness. Film samples are characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and spectrophotometric transmission measurements. XRD confirms the amorphous nature of films and EDS proves a fair compatibility between the detected and chosen compositional elements' percentages. The absorption coefficient values are found to be in the range of 104 cm−1. Tauc's bandgap energy, Eg increases from 1.456 eV to 1.722 eV, while Urbach's energy, Ee shows a decrease from 0.032 eV to 0.015 eV. The refractive index of CZGSe films also decreases along all the studied spectral range. Wemple-DiDomenico and Sellmeier models are applied to study dispersion energies and related parameters. The oscillator resonance energy (Eo) and oscillator dispersion energy (Ed) shows inverse behaviour. The Eo values increase (2.939 eV–3.422 eV), but Ed values show a decrease (30.831 eV–24.342 eV). Many dispersion and nonlinear parameters are also calculated and discussed. The correlation between optical parameters of CZGSe films has been analyzed using Python programming. The obtained findings show the possibility of using these films in many optical applications.

Fabrication and Characterization of Ni-Carbon nanofibers by Electrospinning Technique

Carbon nanofibers with the distribution of magnetic Ni metal (Ni-CNFs) have been synthesized using Nickel (II) acetate tetrahydrate (Ni (OCHCH3)2.4H2O), polyacrylonitrile (PAN) as precursors by electrospinning technique. The as-prepared nanofibers were dried in a vacuum oven, stabilized, and followed by carbonization at 850 °C in N2 atmosphere. Their structural phase composition, microstructure, and magnetic properties have been investigated. The phase formation of pure Ni-CNF without any impurity has been confirmed by X-ray diffraction (XRD) pattern. The average diameter of the nanofibers and the Ni nanoparticles has been calculated to be 159±25.72 nm and 67±11.24 nm, respectively. Energy-dispersive X-ray spectroscopy (EDX) measurement has been carried out to confirm the presence of Ni and C elements with their weight%. Raman spectrum attributes the presence of two characteristic absorption peaks of carbon materials. Room temperature (300 K) magnetic measurement shows the ferromagnetic behavior of Ni-CNF. These nanofibers have the potential to be used in a wide variety of applications including These materials have wide variety of applications as in different magnetic devices (magnetic sensors, magnetic recording devices, and soft magnetic materials.), microwave absorption materials, supercapacitors and batteries etc.

Synthesizing Conducting Poly(Aniline-co-Aminoacetophenone) Nanocomposites based on Polyhydroxy Iron Cation–modified Clay

Abstract: Conductive clay–polymer nanocomposites were prepared via the in situ polymerization of aminoacetophenone and/or aniline monomers (at initial “aminoacetophenone:aniline”) in the presence of polyhydroxy iron cation–modified montmorillonite (MMT-PIC). Fourier transform infrared spectroscopy analysis demonstrated the characteristic bands of the MMT-PIC polymers/copolymers. The morphological properties analyzed and imaged through X-ray diffraction and scanning electron microscopy, respectively, displayed an increasing interlayer distance with the mass loading of PIC and poly(aminoacetophenone-co-aniline) (poly(AAP-co-ANI)), affording intercalated nanocomposites. Energy-dispersive X-ray spectroscopy measurements revealed that the clay experienced a cation exchange of sodium by the PIC, and poly(AAP-co-ANI) was present in large amounts on the nanocomposite surface. The electrical conductivity of the obtained nanocomposites was 5.760 × 10−5 S⋅cm−1. Moreover, the electrochemical behavior of the polymers extracted from the nanocomposites was studied via cyclic voltammetry; the redox processes indicated that the polymerization into activated carbon produced electroactive polymers.

Superconductivity in high-entropy alloy system containing Th

Th-containing superconducting high entropy system with the nominal composition (NbTa)_{0.67}(MoWTh)_{0.33} was synthesized. Its structural and physical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, specific heat, resistivity and magnetic measurements. Two main phases of alloy were observed: major bcc structure and minor fcc. The experimental results were supported by numerical simulation by the DFT Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA).

Green and eco-friendly biosynthesis of zinc oxide nanoparticles using Calendula officinalis flower extract: Wound healing potential and antioxidant activity.

This study aimed to produce zinc oxide nanoparticles with Calendula officinalis flower extract (Co-ZnO NPs) using the green synthesis method. In addition, the antioxidant and wound healing potential of synthesized ZnO NPs were evaluated. The absorbance band at 355 nm, which is typical for ZnO NPs, was determined from the UV-Vis absorbance spectrum. The energy-dispersive X-ray spectroscopy (EDS)measurements revealed a high zinc content of 42.90%. The x-ray diffractometer data showed Co-ZnO NPs with an average crystallite size of 17.66 nm. The Co-ZnO NPs did not have apparent cytotoxicity up to 10 μg/mL (IC50 25.96 μg/mL). C. officinalis ZnO NPs showed partial cell migration and percent wound closure (69.1%) compared with control (64.8%). In addition, antioxidant activities of Co-ZnO NPs with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2 diphenyl-1 picrylhydrazil(DPPH) were evaluated and radical scavenging activity of 33.49% and 46.63%, respectively, was determined. These results suggest that C. officinalis extract is an effective reducing agent for the green synthesis of ZnO NPs with significant antioxidant and wound healing potential.

Facile Preparation of Durable and Eco-Friendly Superhydrophobic Filter with Self-Healing Ability for Efficient Oil/Water Separation.

The superhydrophobic feature is highly desirable for oil/water separation (OWS) operation to achieve excellent separation efficiency. However, using hazardous materials in fabricating superhydrophobic surfaces is always the main concern. Herein, superhydrophobic filters were prepared via an eco-friendly approach by anchoring silica particles (SiO2) onto the cotton fabric surface, followed by surface coating using natural material-myristic acid via a dip coating method. Tetraethyl orthosilicate (TEOS) was used in the synthesis of SiO2 particles from the silica sol. In addition, the impact of the drying temperature on the wettability of the superhydrophobic filter was investigated. Moreover, the pristine cotton fabric and as-prepared superhydrophobic cotton filters were characterised based on Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and contact angle (CA) measurement. The superhydrophobic cotton filter was used to perform OWS using an oil-water mixture containing either chloroform, hexane, toluene, xylene or dichloroethane. The separation efficiency of the OWS using the superhydrophobic filter was as high as 99.9%. Moreover, the superhydrophobic fabric filter also demonstrated excellent durability, chemical stability, self-healing ability and reusability.

Tunable optical and semiconducting properties of eco-friendly-prepared reduced graphene oxide.

Wide bandgap oxidized graphenes have garnered particular interest among the materials explored for these applications because of their exceptional semiconducting and optical properties. This study aims to investigate the tunability of the related properties in reduced graphene oxide (rGO) for potential use in energy conversion, storage, and optoelectronic devices. To accomplish this, we scrutinized crucial parameters of the synthesis process such as reduction time and temperature. Our findings demonstrate that controlling these parameters makes it possible to customize the optical bandgap of reduced graphene oxide within a range of roughly 2.2eV-1.6eV. Additionally, we observed that reduced graphene oxide has strong and superior absorption in the visible region, which is attributable to the existence of OFGs and defects. Notably, our results indicate that the absorption coefficients of reduced graphene oxide are up to almost three times higher (7426mlmg-1 m-1) than those observed in dispersions of exfoliated graphene and graphene oxide (GO). To complement our findings, we employed several spectroscopic and morphological characterizations, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and electrical measurements. The implications of our results are significant for the development and design of future semiconductors for energy conversion and optoelectronic applications.