Wurtzite ZnO Nanoparticles Research Articles

Morphological, structural, and electronic properties of green synthesized ZnO nanoparticles by experimental and DFT+U method – A review

In these decades, researchers have paid much attention to green synthesis methods because of their low cost and eco-friendliness. Among all other semiconductors, ZnO nanoparticles have huge applications in optoelectronics devices, solar cells, photocatalysis, transistors, etc. This review article explains the green synthesis methods and factors affecting the morphology of ZnO nanoparticles. The morphology shows different structures such as nanowires, cubic, hexagonal, flower-like structures, etc. The XPS peaks Zn-2p1/2, Zn-2p3/2, and O-1S suggest that the synthesized nanoparticles are ZnO. The theoretical review part explains the electronic and structural properties of wurtzite ZnO nanoparticles. The implementation of the Hubbard-U scheme in the d and p shells using Local Density Approximation (LDA) and Generalized Gradient Approximation (GGA) shows the drastic change in the electronic and structural properties of ZnO nanoparticles. The optimized lattice parameters and band gap using Hubbard parameters by different DFT codes are tabulated. Also, we compared computational and experimental results.

Simple two-step synthesis of Ag/ZnO nanoparticles with enhanced photocatalytic response

This study presents a simple two-step synthesis method for the fabrication of Ag/ZnO nanocomposites to improve the photocatalytic response of ZnO. The synthesis involves ZnO nanoparticles that were fabricated from the thermal decomposition of commercial zinc acetate. In order to produce Ag/ZnO nanoparticles in a simple two-step process, ZnO nanoparticles were mixed with Ag nanoparticle suspensions previously obtained by the laser ablation of solids in liquids technique at three different fluences. Structural characterization of ZnO powders revealed the presence of single phase wurtzite ZnO nanoparticles with crystal sizes of 20 nm. On the other hand, XRD patterns for a composite sample revealed the presence of signals associated to both ZnO and Ag suggesting that silver nanoparticles were attached to the ZnO particles surface. Optical characterization of the ZnO powders, carried out by UV–vis spectroscopy, showed a strong absorption band centered at 380 nm, which is associated to excitonic transitions in ZnO nanoparticles, whilst absorption measurements of silver nanoparticles colloids revealed the presence of a strong band centered near 412 nm. This band shifts to shorter wavelengths with increasing fluence from 2.6 to 6.2 J cm−2, indicating changes in nanoparticles size. Photocatalytic degradation tests of methylene blue under UV irradiation were carried out using pure ZnO, Ag colloids and Ag/ZnO nanoparticles. After the first 30 min of irradiation, it was observed that the silver nanoparticles reached degradation percentages of 16, 22 and 29% for samples synthesized at 2.6, 4.2 and 6.2 J cm−2, respectively. Meanwhile the ZnO sample reached a value of 13% after 30 min. Regarding the Ag/ZnO composite sample, the percentage of degradation after 30 min was 36%, demonstrating a considerable enhanced photocatalytic activity as compared to ZnO. After 24 h irradiation, Ag/ZnO degraded 95% of the methylene blue solution. It was observed that decorating ZnO with laser produced silver nanoparticles accelerates the photocatalytic response of ZnO by enhancing the activity at short times.

Effect of Oxidizing Agent on the Synthesis of ZnO Nanoparticles for Inverted Phosphorescent Organic Light-Emitting Devices without Multiple Interlayers.

Inverted organic light-emitting devices (OLEDs) have been aggressively developed because of their superiorities such as their high stability, low driving voltage, and low drop of brightness in display applications. The injection of electrons is a critical issue in inverted OLEDs because the ITO cathode has an overly high work function in injecting electrons into the emission layer from the cathode. We synthesized hexagonal wurtzite ZnO nanoparticles using different oxidizing agents for an efficient injection of electrons in the inverted OLEDs. Potassium hydroxide (KOH) and tetramethylammonium hydroxide pentahydrate (TMAH) were used as oxidizing agents for synthesizing ZnO nanoparticles. The band gap, surface defects, surface morphology, surface roughness, and electrical resistivity of the nanoparticles were investigated. The inverted devices with phosphorescent molecules were prepared using the synthesized nanoparticles. The inverted devices with ZnO nanoparticles using TMAH exhibited a lower driving voltage, lower leakage current, and higher maximum external quantum efficiency. The devices with TMAH-based ZnO nanoparticles exhibited the maximum external quantum efficiency of 19.1%.

Employing zinc oxide nanoparticle coating as a corrosion inhibitor for magnesium alloys in distinct aqueous electrolyte

In this investigation, zinc oxide nanoparticles were synthesised using a straightforward microwave-assisted technique. Results showed that the synthesised nanoparticles were hexagonal wurtzite ZnO-nanoparticles with a crystallite size of 6.76 nm, as determined by physio-chemical methods. It reveals, at varying magnifications, the irregularly aggregated, spherically shaped sponge-like structure. Using Fourier transform infrared spectroscopy, corresponding functional groups on ZnO surfaces have been observed. According to absorption measurements, the direct optical bandgap is around 3.29 eV. The photoluminescence spectra may be used to detect crystal defects in the ZnO lattice by looking for red emission and blue band edge emission. An investigation into the anticorrosion capabilities of zinc oxide nanoparticles was conducted, which revealed that the particles have beneficial characteristics when coated with magnesium (Mg) substrates. These materials are evaluated for corrosive resistance with and without a protective coating. Results show that coating significantly increased the protection rate under different electrolyte conditions. Compared to bare Mg plate, the charge transfer resistance Rct was increased when ZnO nanoparticles were coated.
 KEY WORDS: Zinc oxide nanoparticle, Microwave irradiation, Corrosion resistance, magnesium alloy
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 417-430. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.10

Biaxial strain induced tunable electronic properties study of ZnO nanoparticles via first-principles density functional theory

Strain engineering can be used to manipulate electronic and optical properties of ZnO suitable for various applications. In the present work, we have characterized the hydrothermal prepared different wurtzite-ZnO nanoparticles using X-ray diffraction, microscopy and spectroscopy techniques. The lattice parameters of prepared ZnO nanoparticles, obtained from Rietveld refinement of XRD data, have been used for in-depth analysis of the phonon and electronic properties of ZnO. The calculated bandgap Eg using Density functional theory with GGA + U (Generalized Gradient Approximation with Hubbard correction) approach is found to be ∼ 3.48 eV with a strong Zn-3d O-2p hybridization and matches our experimental bandgap value (∼ 3.25 eV). Further, the effect of biaxial strain on the electronic band structure of ZnO has also been studied. A strong non-linear behavior is found in both direct (Γ-Γ) and indirect transitions (Γ-A). Strain application on ZnO may be useful for straintronics and other nano-devices such as NEMS and NOMS.

Tartaric acid-assisted combustion of visible-light-driven Eu-doped ZnO nanoparticles

ZnO nanoparticles doped with 0–5% Eu were synthesized by a tartaric acid-assisted combustion method. The effect of different contents of Eu dopant on phase and morphology was investigated by different techniques. The as-synthesized samples with and without dopant were single phase of hexagonal wurtzite ZnO nanoparticles. The average particle sizes of the as-prepared samples were decreased from 59 nm for pure ZnO to 20 nm for Eu-doped ZnO. The photocatalytic activities of as-synthesized ZnO with and without Eu dopant were investigated through the degradation of methylene blue (MB) under visible light irradiation for 100 min. In this research, 3% Eu-doped ZnO nanoparticles exhibited the best photocatalytic activity in degrading of MB of 97.90% or 5.5 times the photocatalytic activity of pure ZnO nanoparticles. A mechanism for photocatalysis of Eu-doped ZnO nanoparticles was also proposed in this research.

Ball Milling synthesis and characterization of highly crystalline TiO[formula omitted]-ZnO hybrids for photovoltaic applications

In this work, Ball Milling is investigated as a viable synthesis method for highly crystalline TiO2-ZnO composites. The composites were verified using various standard techniques. XRD measurements confirmed the presence of hexagonal wurtzite ZnO and tetragonal TiO2 nano particles. Both XRD and transmission electron microscopy show a mean crystallite size between 12.7 and 15.0 nm. The blend compatibility of the two oxides was investigated by varying the molar ratio of ZnO from 0 to 30%. It is apparent that the morphology compatibility of ZnO and TiO2 plays a significant role in the performance of the final device. The composite specific surface area is seen to increase with ZnO doping. UV–Vis measurements show that its band gap decreases from 3.281 to 3.221 eV. UV–Vis further demonstrated a red-shift of TZHO absorption band which enhances the ability of hybrids to absorb in the visible wavelength range. Scanning electron microscopy suggests that TiO2 and ZnO are morphologically well-matched, and can be used as the electron transport layer in a blended perovskite solar cell. A maximum efficiency of 8% was measured on the PSC with 30% ZnO with Isc=18.4 mA, Voc=0.69 V, and FF=0.65. This efficiency is comparable for PSCs with the hybrid oxide synthesized using other methods, showing that Ball Milling is also a viable method.

Green synthesis of zinc oxide nanoparticles by Ziziphus jujuba leaves extract: Environmental application, kinetic and thermodynamic studies

This research reports, for the first time, the eco-friendly green synthesis of zinc oxide nanoparticles (ZnO NPs) using Ziziphus jujuba leaves extract assisted by microwave irradiation. Eco-friendly prepared ZnO NPs were characterized by different techniques, and the results confirmed the formation of hexagonal wurtzite ZnO nanoparticles with different particle sizes. The prepared ZnO NPs were then used for the adsorption and removal of two different azo dyes; methyl orange (MO), and methylene blue (MB), as well as toxic Pb(II) ions, from a model solution and real samples. The influence of experimental conditions was explored; ZnO NPs mass, contact time, solution pH, solution ionic strength, and solution temperature, and the results showed that most of the MB, MO, and Pb(II) could be removed from the model solution within a few minutes, at ambient conditions. The experimental removal capacities of 5.21, 2.57, and 596 mg of MO, MB, and Pb(II) per gram of microwave-assisted green ZnO NPs (MWG ZnO NPs), respectively, were obtained. The removal of the MB, MO, and Pb(II) using ZnO NPs was studied kinetically and thermodynamically, and the results showed that the experimental data were best fitted using the pseudo-second-order kinetic models, with rate constants of 0.165, 0.364, 247 × 10–6, for the MO, MB, and Pb(II), respectively. The thermodynamics study showed that the process was spontaneous, with an exothermic nature. Finally, the prepared ZnO NPs were used for the removal of MB, MO, and Pb(II) in real wastewater samples, and high removal efficiency was presented. The regeneration and reusability were explored, and the results revealed the applicability of using the MWG ZnO NPs for the removal of MB, MO, and Pb(II) for five consecutive cycles.

Fabrication of novel polyaniline/ZnO heterojunction for exceptional photocatalytic hydrogen production and degradation of fluorescein dye through direct Z-scheme mechanism

In the recent years, direct Z-scheme heterojunctions exhibit an exceptional reactivity in various photocatalytic processes. Hybrid visible light driven photocatalyst consisting of semiconducting metal oxide and conducting polymer have immense capability of destruction of various organic pollutants and production of hydrogen gas as alternative renewable energy source. Herein, a novel hybrid polyaniline/ZnO heterojunction were synthesized by coupling sol-gel and oxidative polymerization of aniline in ultrasonic bath of various intensities for removal of fluorescein dye and producing large amount of hydrogen gas under visible light source. Particularly, the amount of polyaniline plays a pivotal role in optimizing the amount of hydrogen gas produced. The change in the diffraction pattern of Wurtzite ZnO nanoparticles and the remarkable reduction of PL signal intensity suggest the construction of direct Z-scheme heterojunction. The photocatalytic hydrogen production rate estimated on the optimized sample using methanol as scavenger is 9.4 mmolh −1 g −1 which is higher than that of bare ZnO nanoparticles. The sample containing 5 wt% polyaniline exhibits photocatalytic degradation rate of fluorescein dye 0.021 min −1 which is ten folds higher than that of bare ZnO. The results of our research work indicate that polyaniline is efficiently enhances the light absorption and providing an additional electrons that combine with H + to produce H 2 -gas. • Novel polyaniline/ZnO were synthesized by sonochemical route. • Positive shift of the photocatalytic response to visible region. • Exceptional photocatalytic hydrogen evolution. • High stability for five consecutive cycles.

Preparation of ZnO/carbon-TiO2 core-sheath nanofibers film with enhanced photocatalytic properties

ZnO/carbon-TiO2 core-sheath nanofibrous film was fabricated by a combination of electrospinning, tetrabutyl titanate (TBT) treatment and heated treatment. The results of field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction revealed that the wurtzite ZnO nanoparticles were successfully incorporated in carbon nanofibers (NFs) matrix without aggregation. And a uniform TiO2 layer consisting of anatase and rutile covered on the surface of the ZnO/C NFs. The ZnO/C-TiO2 core-sheath NFs film was used to photodegrade rhodamine B and exhibited the photocatalytic efficiency of 98.8%, which was much higher than that of ZnO NFs and ZnO/C NFs. This might be attributed to the ZnO/C-TiO2 core-sheath structure with high separation efficiency of photo-generated electrons and holes. Moreover, ZnO/C-TiO2 core-sheath NFs could be easily recycled without decrease of photocatalytic activity.

Enhanced photoelectrochemical cell performance of Co doped ZnO nanoparticles sensitized by affordable mixed dyes as sensitizer

In the present investigation, a simple sol-gel approach has been employed for the synthesis of hexagonal wurtzite ZnO nanoparticles (NPs). X-ray diffraction (XRD) rietveld study and Raman analysis reveal the mislaid of the mixed phases of ZnO NPs after doping. The scanning electron micrographs and transmission electron microscopy confirm the formation of hexagonal disk-shaped NPs. FTIR, PL, EDX, XPS validate optical and stoichiometric concentration of Co in ZnO lattice. UV-visible DRS study shows absorption edge with humps to the red region of the spectrum with increasing the absorption strength and shortening of band gap as the content of Co (II) increases. Finally, the prepared samples were coated on the surface of cleaned FTO substrate through a simple doctor blade technique and sensitized with prepared dye. The ZnO photoanode shows 0.036% of efficiency (η%) while the photoanodes of Co doped samples expose the enhanced efficiencies of 0.29%, 0.389%, 0.089%.

A Rapid and Facile Electrochemical Approach for Producing ZnO Nanocrystals

ZnO nanoparticles have been produced by a rapid and facile electrochemical method. The crystalline structure and surface morphology of the synthesized nanoparticles were characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction analysis, and Raman spectroscopy. Results show that, by using this approach, high-quality hexagonal wurtzite ZnO nanoparticles with faceted shape, smooth side surface, low agglomeration, particle size ranging from 40 nm to 80 nm, and high crystallinity can be obtained . The direct formation mechanism of the ZnO nanoparticles is also discussed.

Improved photocatalytic activity of ZnO-TiO2 nanocomposite catalysts by modulating TiO2 thickness

We describe fabrication of ZnO-TiO2 nanocomposites with improved photocatalytic activity. The nanocomposite catalysts were synthesized by chemical co-precipitation approach encapsulating wurtzite ZnO nanoparticles (NPs) with anatase TiO2 shell. The TiO2 thickness was controlled by optimizing the weight ratios of ZnO to TiO2 to investigate the effect of TiO2 shell thickness on the photocatalytic properties of ZnO-TiO2 heterojunctions. ZnO NPs could be uniformly coated by TiO2 layers with desirable shell thicknesses. The band edge energy of the prepared nanocomposite catalysts indicated that the thickness of TiO2 layers could decrease the band gaps of the catalysts compared with the pristine ZnO NPs. The photocatalytic property of ZnO-TiO2 nanocomposites was evaluated by measuring photo-degradation of methylene blue (MB) in aqueous media. The all synthesized nanocomposite catalysts showed improved photocatalytic efficiency in comparison with the pristine ZnO NPs relevant to the red shift generated and higher absorption of photons in UV region. The photocatalytic also results revealed that the photo-activity performance of the samples were improved by increasing the shell thickness because of a decline in the measured band-gaps. The kinetic expressions with different orders were also studied and an appropriate model was demonstrated for the photocatalytic degradation process of MB.

Enhanced third-order optical susceptibility in heterogeneous wurtzite ZnO/anatase TiO2 core/shell nanostructures via controlled TiO2 shell thickness

Wurtzite ZnO nanoparticles have been coated by anatase phase TiO2 layers using a chemical co-precipitation technique to synthesize heterogeneous ZnO-TiO2 core-shell nanostructures. The structural characterizations of as-prepared core-shell nanoparticles have been studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray photoelectron spectroscopy (EDX). Linear optical studies have been performed using photoluminescence (PL) emission spectra at an excitation wavelength of 300 nm. A blue shift towards shorter wavelengths has been observed in the NBE-related energies of core-shell samples as compared to blank ZnO core. Nonlinear optical parameters have been examined using the Z-scan technique under a 532 nm Gaussian laser beam with 10 ns short pulse width and 200 Hz repetition rate as an excitation source. All samples have exhibited a negative value of nonlinear refraction index and also reverse saturable absorption due to two-photon absorption phenomenon. The results of Z-scan analysis have revealed the stronger third-order nonlinearities for core-shell nanoheterojunctions compared to blank ZnO nanoparticles. The estimated values of the third-order susceptibility have exhibited measures up to the highest magnitude of 8.10×10−4esu belonging to ZnO-TiO2-1 sample, which shows an enhancement about four times higher than that of blank ZnO.

Photocatalytic degradation of methylene blue with ZnO@C nanocomposites: Kinetics, mechanism, and the inhibition effect on monoamine oxidase A and B

To improve the photocatalytic activity of hexagonal wurtzite ZnO nanoparticles, ZnO@C nanocomposites were synthesized at low temperature via “two-step hydrothermal method”. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and UV–visible diffuse reflectance spectroscopy (UV–Vis DRS) were carried out to characterize the ZnO and ZnO@C photocatalysts, indicating that there was a carbon layer on the surface of the ZnO@C and that the presence of a carbon layer enhanced the response under visible light. The photocatalytic degradation of methylene blue (MB) was chosen as a model reaction to evaluate the photocatalytic activity and stability of the ZnO and ZnO@C photocatalysts. The results indicated that the photocatalytic performance of the ZnO@C07 was approximately 1.78 times higher than that of ZnO. Additionally, the ZnO@C07 photocatalyst showed excellent photocatalytic stability, which was dependent on the stability of the structure of the ZnO@C07 photocatalyst. The possible photocatalytic mechanisms of the ZnO and ZnO@C photocatalysts were proposed based on electron spin resonance (ESR) measurements and the calculation of the synergetic factor. The synergetic effect between ZnO and carbon-layer was on account of the higher concentration of surface OH− species (ratio of OH−/O2− was 0.18 for ZnO and 1.48 for ZnO@C07), and the more surface OH− resulting in higher intensity of ·OH and ·O2− under sunlight irradiation. The inhibition effect between MB and monoamine oxidase A (MAO A) was higher than that of MAO B on the basis of IC50 values with IC50(MB/MAO A) = 0.2 μ M and IC50(MB/MAO B) = 5.6 μ M, which was attributed to the stronger interactions between MB and MAO A (Van Der Waals' force) than that between MB and MAO B (Van Der Waals' force, π-π interaction, π-cation interaction). Our findings provide valuable information on the photocatalytic degradation of organic pollutants by modified metal oxide photocatalysts and offer a synthetic evaluation method to predict the molecular mechanism of the inhibition effect between MB and protein.

Synthesis and characterization of ZnO nanorice decorated TiO2 nanotubes for enhanced photocatalytic activity

In present study, we report on the synthesis of TiO2/ZnO nanocomposite (TZN) films for potential applications as photocatalyst in heterogeneous photo-degradation of Rhodamine B under UVA irradiations. ZnO nano-rice decorated TiO2 nanotubes were successfully synthesized via a facile and effective two-step route. Firstly, TiO2 nanotube arrays were grown by anodic oxidation. Afterwards, ZnO rice shaped nanostructures were decorated by successive chemical bath deposition cycles of 2, 4, 6 and 8. The XRD, FESEM, XPS and μ-XRF results showed that the rice-shaped wurtzite ZnO nanoparticles with dimensions of ca. 1μm × 100 nm were homogeneously distributed on the anatase TiO2 nanotube arrays with highly uniform in the presence of in zinc nitrate hexahydrate and hexamethylenetetramine precursors with 1:4 M ratios. The photodegradation results showed that the photocatalytic activity of TZN films were gradually increased in parallel with the number of ZnO deposition cycles and the best performance was found for TNZ8 film. The RhB photodegradation efficiency was determined to be 65% for bare TiO2 whereas 95% degradation of Rhodamine B was occurred for TNZ8 film which follow pseudo-first-order kinetic. In addition, TZN films exhibited good photostability after four reuses. Also, photocatalytic activity of TZN were tested under UVC, UVB, UVA and visible region irradiations for comparative purposes.

In situ generation and deposition of ZnO nanoparticles on cotton surface to impart hydrophobicity: investigation of antibacterial activity

ABSTRACTThe study of ZnO nanoparticles was prepared and deposited onto cotton fabrics surface via a simple and rapid hydrothermal approach successfully. Fluorosurfactant has been used to stabilize, homogenize the coated ZnONPs and control their shape. The use of fluorosurfactant has improved the durability of ZnONPs dipped on the cotton surface and decreased it’s leaching in a particular surfactant. The surface morphology, crystalline Structure and hydrophobic nature of the uncoated and coated cotton fabric were investigated by scanning electron microscope, X-Ray diffraction, Energy dispersive X-ray spectroscopy and water drop stability with contact angle measurement. SEM and XRD analysis revealed information about the shape and size of the coated ZnO nanoparticles is about 50–80 nm wurtzite ZnO nanoparticles. ZnONPs coated cotton fabric showed the highest antibacterial activity against Bacillus subtilis and Escherichia coli.

Designing biomimetic porous celery: TiO2/ZnO nanocomposite for enhanced CO2 photoreduction

The nanostructured heterojunction photocatalysts are considered promising in photocatalytic reduction in the carbon dioxide. Herein, we demonstrate a simple sol–gel and hydrolysis process to design nanostructured TiO2/ZnO heterojunction, by using the biological template celery stalk. The nanostructured photocatalyst consists of anatase TiO2 and wurtzite ZnO nanoparticles. A well-connected heterojunction, with uniformly distributed nanoparticles, on the pores and folds of celery stems, is obtained. The enhanced specific surface area of 55.5 m2/g is achieved. The crystal structure, morphology and surface composition are investigated by electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Furthermore, we demonstrate the photocatalytic performance of as-synthesized nanostructure TiO2/ZnO heterojunction. The photocatalytic yield, of CO2 reduction into CH4, exhibits a five times increase, from 0.55 to 2.56 µmol h−1 g−1, for the nanocomposite as compared to the pure TiO2. This enhanced performance corresponds to the efficient charge transfer and hindrance in the recombination of electron–hole pairs due to the optimum band positions of ZnO and TiO2. This study demonstrates the potential of using biotemplates to design efficient photocatalysts to convert CO2 into useful solar fuels.

Investigation of Zinc Oxide-Loaded Poly(Vinyl Alcohol) Nanocomposite Films in Tailoring Their Structural, Optical and Mechanical Properties

Wurtzite ZnO nanoparticles, as a nanofiller, were incorporated in a poly(vinyl alcohol) (PVA) matrix to prepare multipurpose nanocomposite films using a solution casting approach. Some advanced analytical techniques were used to investigate the properties of prepared nanocomposite films. The mediation of ZnO nanofillers resulted in modification of structural, optical and mechanical properties of nanocomposite films. A comprehensive band structure investigation might be useful for designing technological applications like in optoelectronic devices. The experimental results were found to be closely dependent on the nanofiller contents. Some theoretical models like Tauc’s and Wemple–DiDomenico, were employed to investigate the band structure parameters. The imaginary part of the dielectric constant was used to investigate the band gap. Then, the Helpin-Tsai model was employed to predict Young’s moduli of the prepared nanocomposite films. On 3 wt.% ZnO nanofiller loading, the optical band gap of the PVA-based nanocomposite film was decreased from 5.26 eV to 3 eV, the tensile strength increased from 25.3 MPa to 48 MPa and Young’s modulus increased from 144 MPa to 544 MPa.

Synthesis, characterization and ferromagnetic properties of Zn1-xMnxO (x ≤ 0.05) nanoparticles

Zn1-xMnxO (x ≤ 0.05) nanoparticles were synthesized by a combination of room temperature precipitation and high temperature calcination. Pure hexagonal wurtzite ZnO nanoparticles with the size of ≤100 nm and a dominant vibrational peak at 437 cm−1 of E2H non-polar optical phonon mode were detected. The present research was succeeded in doping of ZnO lattice by Mn2+ ions, including the detection of an additional peak at 528 cm−1 associated with lattice defects. Magnetic properties of Zn1-xMnxO (x ≤ 0.05) nanoparticles were controlled by correlated spin of Mn–O–Mn exchange couple and lattice disorder. The saturation magnetization of ferromagnetic Zn0.97Mn0.03O was the highest at 51.49 × 10−3 emu/g.