Modification in structural, optical, morphological, and electrical properties of zinc oxide (ZnO) nanoparticles (NPs) by metal (Ni, Co) dopants for electronic device applications

DFT and comparative adsorption study of NiO, MnO, and Mn2NiO4 nanomaterials for the removal of amaranth dye from synthetic water

In the current study, NiO nanoparticles, MnO nanoparticles, and Mn2NiO4 nanocomposites (Ni-NPs, Mn-NPs and MN-NCs, respectively) were synthesized using a facile hydrothermal method, and their performance in the removal of amaranth (AM) dye from synthetic wastewater was compared. XRD, FTIR spectroscopy, SEM, BET analysis, and TGA were performed to characterize the produced catalysts. The effect of pertinent parameters, including pH, dosage of catalysts, temperature, and shaking speed on the uptake of AM was investigated through batch experiments. The MN-NCs showed ultrafast and high efficiency for AM removal compared to their counter parts Mn-NPs and Ni-NPs. Under ideal conditions, the highest adsorption efficiencies of AM onto Ni-NPs, Mn-NPs, and MN-NCs were calculated to be 80.50%, 93.85%, and 98.50%, respectively. The Langmuir isotherm fitted the experimental data of AM removal better as shown by the higher values of r 2, compared to the Freundlich isotherm, indicating monolayer type adsorption of AM. According to kinetic analyses, the adsorption of AM was best described by the pseudo-second-order kinetic model. Further, regeneration/recycling studies showed that MN-NCs retained 79% adsorption efficiency after four cycles. DFT experiments were also conducted to gain a deeper understanding of the process and behavior of AM adsorption. In conclusion, as Ni-NPs, Mn-NPs, and MN-NCs adsorb AM predominantly via electrostatic interaction, they can be applied for the removal of both cationic and anionic dyes by controlling the pH factor.

Optimization of technological processes in the manufacturability of varistors based on recycled ZnO product, with emphasis on environmental sustainability

The main objective described in this paper is the optimization of technological parameters in the production of varistors based on recycled zinc oxide (ZnO). The content of this paper builds on our previous research aimed at proving that hydrometallurgically recovered ZnO material, from electric arc furnace dust, is suitable for applications in these semiconductors, an issue which has received very little attention at present. The focus of this research also corresponds to and supports the visions and strategies of environmental sustainability and the circular economy. Samples of ZnO varistors manufactured for this purpose were analyzed by scanning electron microscopy and then the electrical parameters were measured and calculated. Based on the results of the microstructural analysis and electrical properties, prerequisites for the optimal adjustment of technological parameters such as sintering temperature and sintering time were derived, which will be the starting point for further research.

Biomedical Applications of Green Synthesized Zinc Oxide and Magnesium-Doped Zinc Oxide Nanoparticles Using Aqueous Extract of Ziziphus Oxyphylla Leaves

Zinc oxide (ZnO) and magnesium-doped zinc oxide (Mg-doped ZnO) nanoparticles (NPs) were synthesized using Ziziphus oxyphylla 's aqueous leaf extract as reducing agent. UV-Vis absorption peaks at 324 nm and 335 nm were indicative of ZnO and Mg-doped ZnO, respectively. FTIR absorption bands observed at 3238, 1043, 1400, 1401, 2186 and 2320 cm -1 suggested the presence of phenols, alcohols, saturated hydrocarbons, and possibly alkynes. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy revealed pure, spherical and agglomerated NPs with average size of 35.9 nm (ZnO) and 56.8 nm (Mg-doped ZnO). Both NPs remained active against all bacterial strains with the highest inhibition zones observed against Proteus vulgaris (21.16±1.25 mm for ZnO and 24.1±0.76 mm for Mg-doped ZnO. EtBr fluorescence (cartwheel assay) indicated efflux pump blockage, suggesting its facilitation in the bacterial growth inhibition. Antioxidant potential, determined via DPPH radical scavenging assay, revealed stronger antioxidant potential for Mg-doped ZnO (IC [Formula: see text]/mL) than pure ZnO (IC [Formula: see text]/mL). Furthermore, both NPs showed antileishmanial activity against Leishmania tropica promastigotes (IC [Formula: see text]/mL for Mg-doped ZnO and 64.34±6.56 for ZnO), while neither NP exhibited significant hemolysis, indicating biocompatibility and further assessment for their drugability.

Biofabrication of Mg-doped ZnO nanostructures for hemolysis and antibacterial properties

The aim of this work was to synthesize 0.02 and 0.06 Mg-doped ZnO nanoparticles (NPs) using the aqueous extract of Plectranthus barbatus leaf. The structural integrity of the hexagonal phase was emphasized by X-ray diffraction analysis. The average crystallite size (D) of 0.02 and 0.06 Mg-doped ZnO NPs was found to be 23.83 and 26.95 nm, respectively. The scanning electron microscope images revealed a surface morphology of irregular nano-shapes of about 83 nm diameter with an elongated one-dimensional structure. The hemolysis activity demonstrated the safe nature of the synthesized materials at low doses. Antibacterial activity against S. aureus and E. coli, which assessed using the disc diffusion method, indicated that the prepared NPs could inhibit S. aureus but not E. coli. These findings suggest that the synthesized NPs could be explored for potential applications in biotechnology and medicine.

Cube-shaped Cobalt-doped zinc oxide nanoparticles with increased visible-light-driven photocatalytic activity achieved by green co-precipitation synthesis

From the perspective of environmental protection, the highly efficient degradation of antibiotics and organic dyes in wastewater needs to be tackled as soon as possible. In this study, an ecofriendly and green cube-shaped cobalt-doped zinc oxide nanoparticles (Co-ZnO NPs) photocatalyst using Pterocladia Capillacea (P. Capillacea) water extract loaded with 5, 10, and 15% cobalt ions were formed via co-precipitation process to degrade antibiotics. The prepared Co-ZnO NPs were tested as a photocatalyst for the photodegradation of ciprofloxacin (CIPF) in the presence of a visible LED-light source. Co-ZnO NPs have been obtained through the co-precipitation method in the presence of P. Capillacea extract as a green capping agent and reducing agent, for the first time. Several characterization techniques including FTIR, XRD, BET, XPS, TEM, EDX, SEM, TGA and DRS UV-Vis spectroscopy were applied to study the prepared Co-ZnO NPs. XRD results suggested that the average size of these NPs ranged between 42.82 and 46.02 nm with a hexagonal wurtzite structure. Tauc plot shows that the optical energy bandgap of ZnO NPs (3.19 eV) gradually decreases to 2.92 eV by Co doping. Examinations showed that 5% Co-ZnO NPs was the highest efficient catalyst for the CIPF photodegradation when compared with ZnO NPs and other 10 and 15% Co-ZnO NPs. A 10 mg/L solution of CIPF was photo-degraded (100%) within the first 15 min irradiation. The kinetics showed that the first-order model is suitable for displaying the rate of reaction and amount of CIPF elimination with R2 = 0.952. Moreover, central composite design optimization of the 5% Co-doped ZnO NPs was also investigated.

Investigation of structural, electronic and optical properties of two-dimensional MoS2-doped-V2O5 composites for photocatalytic application: a density functional theory study

In the present research, the structural, electronic and optical properties of transition metal dichalcogenide-doped transition metal oxides MoS₂-doped-V₂O₅ with various doping concentrations (x = 1-3%) of MoS₂ atoms are studied by using first principles calculation. The generalized gradient approximation Perdew-Burke-Ernzerhof simulation approach is used to investigate the energy bandgap (E_g) of orthorhombic structures. We examined the energy bandgap (E_g) decrement from 2.76 to 1.30 eV with various doping (x = 1-3%) of molybdenum disulfide (MoS₂) atoms. The bandgap nature shows that the material is a well-known direct bandgap semiconductor. MoS₂ doping (x = 1-3%) atoms in pentoxide (V₂O₅) creates the extra gamma active states which contribute to the formation of conduction and valance bands. MoS₂-doped-V₂O₅ composite is a proficient photocatalyst, has a large surface area for absorption of light, decreases the electron-hole pairs recombination rate and increases the charge transport. A comprehensive study of optical conductivity reveals that strong peaks of MoS₂-doped-V₂O₅ increase in ultraviolet spectrum region with small shifts at larger energy bands through increment doping x = 1-3% atoms of MoS₂. A significant decrement was found in the reflectivity due to the decrement in the bandgap with doping. The optical properties significantly increased by the decrement of bandgap (E_g). Two-dimensional MoS₂-doped-V₂O₅ composite has high energy absorption, optical conductivity and refractive index, and is an appropriate material for photocatalytic applications.

Simultaneous fluorescence sensing of vitamin B2 and sulfur ions based on fluorescent copper nanoparticles

In this study, the F-CuNPs were synthesized by a modified liquid-phase chemical reduction method. Throughout the preparation process, anhydrous copper sulfate was used as the copper source, and ascorbic acid in the NaOH solution served as the reducing and protective agent. Förster resonance energy transfer (FRET) may exist between F-CuNPs and vitamin B2 due to the large spectral overlap between the fluorescence emission spectra of F-CuNPs and the UV-vis absorption spectra of vitamin B2. Therefore, the detection of vitamin B2 was designed based on a FRET system between F-CuNPs and vitamin B2. With S^2- into the F-CuNPs&VB2 system, the fluorescence intensity of vitamin B2 was quenched, while the fluorescence intensity of F-CuNPs was almost unchanged. There may be a specific reaction between S^2- and vitamin B2. Therefore, the research system can be further used to detect S^2- based on ratiometric fluorescent probe. The research findings show that the linear range of vitamin B2 was 0.51 nM-34.64 nM with a detection limit of 0.25 nM (S/N = 3), the linear range of S^2- was 0.64 μM-60.00 μM with a detection limit of 0.32 μM (S/N = 3). Furthermore, the simultaneous fluorescent sensing system has high sensitivity and selectivity. Therefore, this system was designed and successfully used to detect the content of vitamin B2 and S^2- in actual samples to find a new effective method to detect analytes.

Optimizing Structural, Optical, Dielectric, and Magnetic Properties of (Bi1-x La x )FeO3 (0.00 ≤ x ≤ 0.06) Sintered Ceramics

(Bi_1-x La _x )FeO₃ (0.00 ≤ x ≤ 0.06) ceramics have been synthesized through a mixed oxide route to investigate their structural, morphological, optical, dielectric, and magnetic properties. All the samples are revealed to be in rhombohedral structures along with the R3c space group and 161 space group number. A high relative permittivity and the lowest tangent loss are observed in BLFO samples at the frequency range 1-100 MHz. The optical studies show that the excitation energy increases with the increasing La content. Moreover, the magnetization being strongly affected by crystallite size and microstrain has been investigated. The band gap energy increases with the increasing La content. The overall result of pure and doped La contents in BFO ceramics shows enhanced structural, dielectric, and optical properties.

Effect of the Deposit Temperature of ZnO Doped with Ni by HFCVD

The effect of the deposit temperature of zinc oxide (ZnO) doped with nickel (Ni) by hot filament chemical vapor deposition (HFCVD) technique is reported in this work. The technique allows depositing ZnO:Ni in short intervals (1 min). A deposit of undoped ZnO is used as a reference sample. The reference sample was deposited at 500 °C. The ZnO:Ni samples were deposited at 500 °C, 400 °C, 350 °C, and 300 °C. The samples were studied using structural, morphological, and optical characterization techniques. The Ni incorporation to the ZnO lattice was verified by the shift of the X-ray diffraction peaks, the Raman peaks, the band gap, and the photoluminescence measurements. It was found that the deposit temperature affects the structural, morphological, and optical properties of the ZnO:Ni samples too. The structure of the ZnO:Ni samples corresponds to the hexagonal structure. Different microstructures shapes such as spheres, sea urchins, and agglomerate were found in samples; their change is attributed to the deposit temperature variation. The intensity of the photoluminescence of the ZnO:Ni improves concerning the ZnO due to the Ni incorporation, but it decreases as the deposit temperature decreases.

Casting Zinc Oxide Nanoparticles Using Fagonia Blend Microbial Arrest

Physical and chemical methods for production of nanoparticles (NPs) are not only harmful for environment but also toxic for living organism. The present study attempts to synthesize ZnO NPs using the natural plant extract of Fagonia cretica. The phytochemical screening of F. cretica water extract was performed to check the presence of biologically active compounds like alkaloids, tannins, carbohydrates, proteins, phenols, saponins, flavonoids, and steroids. Well-prepared ZnO NPs given sharp absorption peak at 362 were confirmed by UV-visible. XRD analysis showed the ZnO NPs having wurtzite hexagonal structure with crystalline form. TEM analysis endorses flower-shaped ZnO nanoparticles ~ 100-1000 nm. FTIR spectrum suggested the involvement of phenolic groups and amino acids and amide linkages in protein performs as the stabilizing agent in the synthesis of ZnO NPs. The ZnO NPs showed strong antibacterial behavior against two bacterial strains Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. In addition, ZnO NPs exhibited strong antioxidant activity of 79%:85.6%:89.9% at 5 μg/mL:10 μg/mL:5 μg/mL concentration of ZnO NPs respectively. This work indicates that Fagonia is considered to be appropriate and promising candidate for extending the innovative applications in the field of medicine and industry and also helpful and useful to the scientific communities.

Advanced nanomaterials for modulating Alzheimer's related amyloid aggregation

Alzheimer's disease (AD) is a common neurodegenerative disease that brings about enormous economic pressure to families and society. Inhibiting abnormal aggregation of Aβ and accelerating the dissociation of aggregates is treated as an effective method to prevent and treat AD. Recently, nanomaterials have been applied in AD treatment due to their excellent physicochemical properties and drug activity. As a drug delivery platform or inhibitor, various excellent nanomaterials have exhibited potential in inhibiting Aβ fibrillation, disaggregating, and clearing mature amyloid plaques by enhancing the performance of drugs. This review comprehensively summarizes the advantages and disadvantages of nanomaterials in modulating amyloid aggregation and AD treatment. The design of various functional nanomaterials is discussed, and the strategies for improved properties toward AD treatment are analyzed. Finally, the challenges faced by nanomaterials with different dimensions in AD-related amyloid aggregate modulation are expounded, and the prospects of nanomaterials are proposed.

Pomegranate Peel Extract-Mediated Green Synthesis of ZnO-NPs: Extract Concentration-Dependent Structure, Optical, and Antibacterial Activity

Plant-based nanoparticles (NPs) have many advantages over physical and chemical methods and featured with several medicinal and biological applications. In this study, zinc oxide NPs (ZnO-NPs) were synthesized using pomegranate peel aqueous extract, under mild and ecofriendly conditions. The ZnO-NPs structure, morphology, and optical properties were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR), and ultraviolet-visible (UV-Vis). Antibacterial activity against Gram-positive and Gram-negative strains were evaluated using the disk diffusion method. The effect of extract concentration (20, 30, and 40 mL) on the final properties of NPs, as well as the NPs concentration used for antibacterial test (50, 100, and 200 mg/mL), were also studied. The results indicate a hexagonal structure with particle size increases as extract concentration increase (D  = 18.53, 29.88, and 30.34 nm), while the optical bandgap was decreased (Eg = 2.87, 2.80, and 1.92 eV). The antibacterial activity of ZnO-NPs indicated high efficiency, similar or even higher than that of the control azithromycin, more against S. aureus, increased with NPs concentration, and preferred when NPs prepared from high extract concentration. Such promising physicochemical properties support the usefulness and efficacy of the reported bio-route for production of ZnO-NPs and may encourage its application for large-scale production.

Room-Temperature Ferromagnetism in Cu/Co Co-Doped ZnO Nanoparticles Prepared by the Co-Precipitation Method: For Spintronics Applications

In current work, pure ZnO and Zn_0.96-x Cu_0.04Co _x O (0 ≤ x ≤ 0.05) nanoparticles were synthesized by the co-precipitation method. Structural analysis and phase determination of the formed nanoparticles was carried out using X-ray diffraction (XRD) and Williamson-Hall plots. The hexagonal wurtzite structure was manifested by all the samples with divergent microstructures. The change in lattice parameters, bond length, dislocation density, and lattice strain indicates that Cu and Co were successfully incorporated. Average crystallite size was found to be in the range of 32.16-45.42 nm for various doping concentrations. Field emission scanning electron microscopy results exhibited that the surface morphology is an amalgam of spherical-like and hexagon-like structures. Spherical-shaped grains were homogeneous and evenly distributed all over the structure. Fourier transform infrared spectra indicated that the absorption bands were blue-shifted with increasing Co concentration. The UV-visible absorption spectra showed high absorption in the UV region and weak absorption in the visible region. An increase in the energy band gap for the maximum absorption peak was observed from 3.49 eV for ZnO to 3.88 eV for Zn_0.91Cu_0.04Co_0.05O. The Burstein-Moss effect explained the noticed blue shift in absorption spectra and energy band gaps. The vibrating sample magnetometer study revealed the change in the diamagnetic behavior of pure ZnO to the ferromagnetic behavior of the prepared nanoparticles at room temperature for different doping concentrations. In the current study, we have developed the room-temperature ferromagnetism (RTFM) for Cu and Co co-doped ZnO nanoparticles. Since RTFM is the key objective for dilute magnetic semiconductors, therefore it can be served as the desirable expectant for spintronics applications with improved functionalities and device concepts.

Green Facile Synthesis of Silver-Doped Zinc Oxide Nanoparticles and Evaluation of Their Effect on Drug Release

Silver doped zinc oxide nanoparticles (ZANPs) were synthesized by the gelatin mediated and polymerized sol-gel method, and a calcination temperature of 700 °C was applied for 2 h. X-ray diffraction (XRD), FESEM, TGA, DSC, and EDS were performed to study the structure of the prepared nano-powders. Both cubic silver and hexagonal ZnO diffraction peaks were detected in the XRD patterns. The XRD results, analyzed by the size strain plot (SSP) and Scherrer methods, showed that the crystalline sizes of these nanoparticles increased as the Ag concentration increased. The results were observed via transition electron microscopy (TEM), where the particle size of the prepared samples was increased in the presence of silver. Catechin was chosen as a drug model and was loaded into the hydrogels for release studies. The drug content percentage of catechin in the hydrogels showed a high loading of the drug, and the highest rate was 98.59 ± 2.11%, which was attributed to the Zn0.97Ag0.03O hydrogels. The swelling of the samples and in vitro release studies were performed. The results showed that Zn0.91Ag0.09O showed the highest swelling ratio (68 ± 3.40%) and, consequently, the highest release (84 ± 2.18%) within 300 min. The higher amount of silver ions in the hydrogel structure causes it to enhance the osmotic pressure of the inner structure and increases the relaxation of the structure chain.

Nanostructured nickel doped zinc oxide material suitable for magnetic, supercapacitor applications and theoretical investigation

This Paper describes the synthesis of nickel doped ZnO is planned by chemical co-precipitation techniques. The prepared nanostructured nickel doped zinc oxide samples were analyzed by thermogravimetric differential thermal analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infra red (FTIR), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR), and cyclic voltametry (CV). Nanostructure nickel doped ZnO materials have developed as promising for the basis of its broad range of employing in diverse areas. The attractive properties of nickel doped ZnO materials are highly demanded in high-energy potential applications. The nickel doped zinc oxide materials are hexagonal wurtzite arrangement is confirmed by XRD. The morphological -features of FE-SEM show nickel doped zinc oxide NPs are the structure of spherical type with agglomeration. The calculated particle size 11 nm is confirmed by HR-TEM. EPR spectra of nickel doped zinc oxide nanoparticles are ferromagnetic nature. Further, CV studies of Ni doped ZnO materials of the specific capacitance value is 133 Fg^-1 at the scan rate 10 mVs^-1 it is suitable for super capacitor application. The quantum chemical calculations were done by using DFT techniques through B3LYP/LANL2DZ level of basis set.

Investigating the Impact of Cu2+ Doping on the Morphological, Structural, Optical, and Electrical Properties of CoFe2O4 Nanoparticles for Use in Electrical Devices

This study investigated the production of Cu²⁺-doped CoFe₂O₄ nanoparticles (CFO NPs) using a facile sol−gel technique. The impact of Cu²⁺ doping on the lattice parameters, morphology, optical properties, and electrical properties of CFO NPs was investigated for applications in electrical devices. The XRD analysis revealed the formation of spinel-phased crystalline structures of the specimens with no impurity phases. The average grain size, lattice constant, cell volume, and porosity were measured in the range of 4.55–7.07 nm, 8.1770–8.1097 Å, 546.7414–533.3525 ų, and 8.77–6.93%, respectively. The SEM analysis revealed a change in morphology of the specimens with a rise in Cu²⁺ content. The particles started gaining a defined shape and size with a rise in Cu²⁺ doping. The Cu_0.12Co_0.88Fe₂O₄ NPs revealed clear grain boundaries with the least agglomeration. The energy band gap declined from 3.98 eV to 3.21 eV with a shift in Cu²⁺ concentration from 0.4 to 0.12. The electrical studies showed that doping a trace amount of Cu²⁺ improved the electrical properties of the CFO NPs without producing any structural distortions. The conductivity of the Cu²⁺-doped CFO NPs increased from 6.66 × 10⁻¹⁰ to 5.26 × 10⁻⁶ ℧ cm⁻¹ with a rise in Cu²⁺ concentration. The improved structural and electrical characteristics of the prepared Cu²⁺-doped CFO NPs made them a suitable candidate for electrical devices, diodes, and sensor technology applications.