Synthesis of ZnO Nanoparticles Based on Zn Complex Achieved from L‐leucine

In the present study, ZnO nanoparticle preparation in a water‐base medium without using toxic chemicals was investigated. Zinc (II) acetate dehydrate, L? leucine and 5? sulfosalicylaldehyde sodium salt were utilized as the starting materials. X? ray diffraction analyses proved that ZnO was achieved as a unique phase. The highest value of crystallinity was obtained at 600 °C and the minimum values of crystallite size and lattice strain were reported at 400 and 500 °C, respectively. The photoluminescence spectroscopy showed that firing at 500 °C leads to decrease the point defects in ZnO structure. SEM and TEM images confirmed the relation between the firing temperature, the degree of crystallinity and the crystallite size. Firing at 400 °C leads to form ZnO nanoparticles with a size distribution ranging from 15 to 50 nm with cubic, circle and hexagonal shapes. By increasing the temperature to 500 °C, the nanoparticles dimensions increase to 30–60 nm. The particle size of sample ‘c’ is more than 50 nm. The optimum temperature to achieve the goal of this research, namely a high crystallinity and low structure defects, was found to be 500 °C.     

Facile synthesis of flat crystal ZnO thin films by solution growth method: A micro-structural investigation

Flat crystal ZnO thin films were prepared by chemical bath deposition technique onto glass substrates. XRD patterns of the films deposited at about 80 °C and annealed at 200 °C for 1 h in oxygen environment revealed the existence of polycrystalline hexagonal wurtzite phase with c-axis orientation of crystallites in the films. The crystallite size and lattice strain from X-ray line broadening profile were evaluated using the Scherrer method and Williamson–Hall method. Structural parameters such as dislocation density, stacking faults probability, lattice constants, lattice stress, unit cell volume, internal parameter, texture and number of crystallites per unit area have also been calculated. Surface morphology of the films was analyzed by scanning electron microscopy and atomic force microscopy. Photoluminescence spectrum at room temperature exhibited two luminescence centers, one is for UV emission (near band edge emission) located at 3.18 eV and another is for deep level emission located at 2.56 eV.     

Synthesis,magnetic properties and X-ray analysis of Zn0.97X0.03O nanoparticles (X = Mn,Ni, and Co) using Scherrer and size–strain plot methods

Un-doped and doped ZnO nanoparticles (Zn_0.97X_0.03O-NPs, X = Mn, Co, and Ni) were synthesized from a metal acetate precursor and acetic acid by a modified sol–gel combustion method. The compounds were synthesized at calcination temperatures of 650 °C for 1 h. The synthesized un-doped/doped ZnO-NPs were characterized by X-ray diffraction analysis (XRD) and high-magnification transmission electron microscopy (TEM). The XRD results revealed that the sample product was crystalline with a hexagonal wurtzite phase. The TEM showed ZnO-NPs nearly spherical shapes and a non-uniform shape for doped ZnO-NPs. The crystalline development in the ZnO-NPs was investigated by X-ray peak broadening. The size–strain plot (SSP) method was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of the un-doped and doped ZnO-NPs. Physical parameters such as strain, stress and energy density values were calculated more precisely for all reflection peaks of XRD corresponding to the wurtzite hexagonal phase of ZnO lying in the range of 20–80° from the SSP results. The vibrating sample magnetometer (VSM) was also used to study the magnetic behavior of the samples in the ceramic form. The obtained results showed that strain play an important role in peak broadening; moreover, the mean crystalline size of the un-doped and doped ZnO-NPs estimated from the TEM and the SSP method were highly inter-correlated.     

Structural,thermal, dielectric and optical behaviour investigations of water-free ZnO/lyotropic liquid crystal nanocolloids

ABSTRACT

Zinc oxide (ZnO) nanoparticles of spherical symmetry (average size of ≈ 20 nm) have been synthesised via a non-aqueous lyotropic liquid crystalline (LLC) templating process. Lyotropic liquid crystalline nanocolloids are prepared via dispersing 0.05, 0.1 and 0.5 wt.% ZnO nanoparticles in non-aqueous lyotropic phase. No structural phase change has been seen with the doping of nanoparticles as stable lamellar phases are observed in all the cases. Stability of the lamellar structure and orientation of the ZnO nanoparticles in the liquid crystalline matrix may be attributed to the interfacial surface charge interactions. A significant increase and pronounced dispersion in dielectric permittivity of the ZnO/LLC nanocolloids could be the result of parallel coupling among guest/host, higher dipole- moment of the ZnO nanoparticles and Maxwell-Wagner polarisation. The variation of relaxation parameters has also been discussed and correlated with the dielectric and structural parameters. ZnO/lyotropic nanocolloids devices exhibit dc conductivity of the order of 10^?5S/m owing to the increase in the number of ions (of the order of 10¹⁹m^?3) in the doped systems. Nanocolloids exhibits, the refractive index of range 1.40 to 1.45 and the wide bandgap of the range 4.1–4.5 eV.     

Cytotoxic performance of green synthesized Ag and Mg dual doped ZnO NPs using Salvadora persica extract against MDA-MB-231 and MCF-10 cells

In this study, dual doped Zinc oxide nanoparticles consisted of silver and magnesium were prepared by Salvadora persica extract. Powder X-ray diffraction (PXRD) analysis displayed the formation of wurtzite ZnO phase nanostructures and dual doped nanoparticles. The morphological observations of scanning electron microscopy (SEM) confirmed the hexagonal morphology of prepared nanoparticles. The Raman scattering of this product exhibited the first and second orders of polar and non-polar modes that are the characteristic bonds of a wurtzite structure. The toxicity effects of synthesized un-doped, as well as Ag and Mg dual doped ZnO NPs on breast cancer cell (MDA-MB-231) and breast normal cell (MCF-10A) lines, were investigated by the means of MTT test. Accordingly, in comparison to the case of silver and magnesium doped zinc oxide nanoparticles, the un-doped ZnO NPs caused a more toxic impact on MDA-MB-231cells. There was a lack of any significant toxicity effects from un-doped and Ag and Mg dual doped ZnO nanoparticles on the experimented normal cell line (MCF-10A). The gathered results were indicative of a lower toxicity effect in doped nanoparticles when compared to un-doped nanoparticles and therefore, it can be stated that the doping of silver and magnesium metals produces more reliable zinc oxide nanoparticles.     

Photocatalytic studies of silver doped ZnO nanoparticles synthesized by chemical precipitation method

Ag-doped ZnO nanoparticles (Zn_1?xAg_xO; where x = 0.00–0.05) were synthesized by chemical precipitation method. The synthesized products were characterized by X-ray diffraction, scanning electron microscope (SEM), transmission electron microscope (TEM) and UV–Vis spectrometer. The SEM and TEM micrographs revealed the agglomerated spherical-like morphology and the measurements show that the size of crystallites is in the range of 10–40 nm. Optical measurements indicated a red shift in the absorption band edge after Ag doping. The band gap values of as prepared undoped and doped with silver samples were found to decrease with increase in temperature from 300 to 800 °C. Photocatalytic activities of ZnO and Ag doped ZnO were evaluated by irradiating the sample solution to ultraviolet light by taking methylene blue as organic dye. The experiment demonstrated that the photo-degradation efficiency of 1 mol% Ag-doped ZnO was significantly higher than that of undoped and 2–5 mol% Ag doped ZnO under ultraviolet light irradiation.     

Structural and thermal properties of polysulfone-ZnO nanocomposites

Polymer nanocomposite thin film of polysulfone with different concentration of ZnO was prepared by solution grown technique. This paper presents a study on the structural and thermal properties of ZnO filled Polysulfone (PSF) nanocomposites. The structural morphology of the resulting nanocomposites was investigated by X-ray diffraction (XRD), Scanning electron microcopy (SEM), and Atomic force microscopy (AFM). Thermal properties of PSF nanocomposites samples were investigated by Differential thermal analysis, Thermal gravimetric, and Differential thermal gravimetric. Structural result shows that the ZnO nanofiller with different mass% in polymer matrix cause the significant variation of lattice spacing, crystallite size, and percentage crystallinity. XRD result shows that the amorphous behavior of PSF (Pristine) is increasing with incorporation of ZnO nanoparticle in PSF matrix. The SEM and AFM images show the change in structural morphology of PSF due to incorporation of ZnO nanoparticles. The thermal analysis result shows that the significant thermal degradation of polysulfone nanocomposites due to catalytic behavior of ZnO nanoparticles.     

Synthesis, characterization and antimicrobial investigation of mechanochemically processed silver doped ZnO nanoparticles

The application of nanomaterials has gained considerable momentum in various fields in recent years due to their high reactivity, excellent surface properties and quantum effects in the nanometer range. The properties of zinc oxide (ZnO) vary with its crystallite size or particle size and often nanocrystalline ZnO is seen to exhibit superior physical and chemical properties due to their higher surface area and modified electronic structure. ZnO nanoparticles are reported to exhibit strong bacterial inhibiting activity and silver (Ag) has been extensively used for its antimicrobial properties since ages. In this study, Ag doped ZnO nanoparticles were synthesized by mechanochemical processing in a high energy ball mill and investigated for antimicrobial activity. The nanocrystalline nature of zinc oxide was established by X-ray diffraction (XRD) studies. It is seen from the XRD data obtained from the samples, that crystallite size of the zinc oxide nanoparticles is seen to decrease with increasing Ag addition. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) data also supported the nanoparticle formation during the synthesis. The doped nanoparticles were subjected to antimicrobial investigation and found that both increase in Ag content and decrease in particle size contributed significantly towards antimicrobial efficiency. It was also observed that Ag doped ZnO nanoparticles possess enhanced antimicrobial potential than that of virgin ZnO against the studied microorganisms of Escherichia coli and Staphylococcus aureus.     

Investigation of the structural and thermal properties of Y,Ag and Ce-assisted SiO<Subscript>2</Subscript>–Na<Subscript>2</Subscript>O–CaO–P<Subscript>2</Subscript>O<Subscript>5</Subscript>-based glasses derived by sol–gel method

A glass with the composition of the SiO₂–Na₂O–CaO–P₂O₅ was synthesized by sol–gel method at temperature of 900 °C, and then yttrium-, silver- and cerium-containing glasses were prepared at the same conditions using this base system. The structural and thermal properties of the glass samples were investigated by X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy-dispersive X-ray (EDX) spectroscopy and differential thermal analysis techniques. The Ca₅(PO₄)₂(SiO₄)₆ phase having the orthorhombic crystal system is detected for each sample without any secondary phase, and this phase is confirmed by the FTIR spectra. With the addition of Y, Ag and Ce to the SiO₂–Na₂O–CaO–P₂O₅ system, the variations in the average crystallite size, crystallinity percent, lattice parameters and unit cell volume are observed. A decrease in the crystallization peak temperature and the changes in the glass transition temperature are seen with the addition of Y, Ag and Ce to the base system. The addition of Y, Ag and Ce to the base glass increases significantly its density. The EDX spectra of the as-prepared samples verify the introduction of the as-mentioned elements.     

Analysis of meridional x-ray diffraction pattern of the γ form of nylon 6 and comparison of paracrystalline and microstrain models of lattice disorder

Analysis of the increase in the width of the seven meridional (OkO) reflections of the γ form of nylon 6 suggests microstrain rather than paracrystallinity as the source of lattice disorder along the chain axis. It is shown that the intensity of the (020) reflection depends not only on the amount of γ phase present in the fiber, but is also influenced by orientation, Lorentz factor, and crystallite size. Calculations confirm the presence of a weak, diffuse meridional band at 2θ=6° (Cu Kα) when the coherence length along the chain axis corresponds to less than two unit cells.     

Preparation and characterization of nanocomposite ZnO–Ag thin film containing nano-sized Ag particles: influence of preheating,annealing temperature and silver content on characteristics

Nanocomposite ZnO–Ag thin film containing nano-sized Ag particles have been grown on glass substrate by spin-coating technique using zinc acetate dihydrate as starting precursor in 2-propanol as solvent and monoethanolamine as stabilizer. Silver nanoparticles were added in the ZnO sol using silver nitrate dissolved in ethanol-acetonitrile. Their structural, electrical, crystalline size and optical properties were investigated as a function of preheating, annealing temperature and silver content. The results indicated that the crystalline phase was increased with increase of annealing temperature up to 550 °C at optimum preheating temperature of 275 °C. Thermal gravimetric differential thermal analysis results indicated that the decomposition of pure ZnO and nanocomposite ZnO–Ag precursors occurred at 225 and 234 °C, respectively with formation of ZnO wurtzite crystals. The scanning electron microscopy and atomic force microscopy revealed that the surface structure (the porosity and grain size) of the ZnO–Ag thin film (the film thickness is about 379 nm) was changed compared to pure ZnO thin film. The result of transmission electron microscopy showed that Ag particles were about 5 nm and ZnO particles 58 nm with uniform silver nanoclusters. Optical absorption results indicated that optical absorption of ZnO–Ag thin films decreased with increase of annealing temperature. Nanocomposite ZnO–Ag thin films with [Ag] = 0.068 M and [Ag] = 0.110 M showed an intense absorption band, whose maximum signals appear at 430 nm which is not present in pure ZnO thin films. The result of X-ray photoelectron spectroscopy revealed that the binding energy of Ag 3d_5/2 for ZnO–Ag shifts remarkably to the lower binding energy compared to the pure metallic Ag due to the interaction between Ag and ZnO.     

Synthesis and characterization of highly preferred orientation polycrystalline Co-doped ZnO thin films prepared by improved sol–gel method

Highly preferred orientation polycrystalline Zn_1?xCo_xO (x = 0, 0.03, 0.06, 0.09) thin films were prepared by improved sol–gel method on quartz glass substrates. The structural, optical and magnetic properties were investigated. The X-ray diffraction patterns show that all the samples have the same structure with one highly oriented c-axis (002) peak. None of the samples showed any signal of impurity phases. The c-axis lattice constant increased linearly with the increase in Co doping content, indicating that the doping of Co ions into the host lattice did not change the wurtzite structure of ZnO. UV–Vis transmittance spectroscopy showed that the average optical transmittance of the films is about 90 % in visible wavelength range. The optical band gap (Eg) decreased with increasing Co content. Also, the results of vibration sample magnetization ascertained the ferromagnetic behavior of Co-doped ZnO, having a Curie temperature higher than room temperature.     

Thin films of ZnO:M synthesized by ultrasonic spray pyrolysis

High optical quality ZnO:M@Si nanocomposites (where M is the doping element) were obtained by ultrasonic spray pyrolysis. The variation of experimental conditions, the use of various precursors and dopants demonstrated that the morphology of zinc oxide nanoparticles is mainly determined by the sort of the doping element. The luminescence spectra confirm indirectly the isomorphous incorporation of the dopant ions into the zinc oxide lattice.     

Effect of processing consitions on the development of morphology in clay nanoparticle filled nylon 6 fibers

The effect of melt temperature on the phase behavior and preferential orientation development in Nylon 6/montmorillonite nanocomposites were investigated at melt spinning temperatures ranging from 230° to 250°C. The fibers were found to exhibit mostly γ crystalline form that is typical of Nylon 6 filled with montmorillonite nanoparticles. At higher take-up speeds α-crystals begin to appear in the crystalline phase. The presence of nanoparticles was found to impart substantial chain orientation levels even at low to moderate take up speeds reaching a plateau at moderate take up speeds. This was attributed to the increased spin line stress in the presence of nanoparticles that increase the overall viscosity due to their large contact areas with the polymer chains. This increased spinline tension was found to cause fiber breakup at moderate speeds. Increasing melt temperature from 230° to 250°C alleviated this problem.     

Physicochemical Interaction of ZnO Fine Particles with 5‐Mono‐(4‐carboxyphenyl)‐10,15,20‐Triphenylporphyrin

This study deals with an investigation on the preparation and physicochemical interactions of ZnO nanoparticles with acid functionalized porphyrin [5‐mono‐(4‐carboxyphenyl)‐10,15,20‐triphenylporphyrin (CPTPP)] for photovoltaic applications in a detailed manner. Zinc acetate and sodium hydroxide were used as the starting materials for the synthesis of ZnO nanoparticles at 60 °C in an alcoholic medium. The freshly prepared fine particles were then functionalized with CPTPP. Both the virgin and pregnant ZnO particles were characterized by using UV‐Visible spectrophotometry (UV), fluorescence emission (PL), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The band gap energy obtained for ZnO particles, having a value of 3.47 eV, shows significant quantum confinement effect and enhanced photophysical activity. FTIR analysis of the doped ZnO nanostructures showed the presences of some chemical species. SEM analysis revealed a clear change in the surface morphologies of undoped ZnO. The average crystallite size of nanoparticles, calculated from XRD peaks, was found in the nano regime. The lattice parameters calculated for ZnO nanocrystals were also found in good agreement with those given in the literature. From the enhancement in the red shift of the UV‐Vis spectra, it is concluded that hybridization of acid functionalized porphyrin can cause a significant expansion in the total absorption region of ZnO semiconductor for photovoltaic applications.     

Organic–inorganic nanocomposites of (2‐hydroxypropyl)cellulose as a precursor of nanocrystalline zinc oxide layers

The sol–gel method of synthesis of the hybrid nanocomposite films of ZnO/(2‐hydroxypropyl) cellulose (HPC) on silica glass is presented. The sol phases were prepared for different weight ratios of zinc acetate dihydrate to HPC in the presence of triethylamine (TEA). Raman spectrum of the mixture of ZnAc and HPC indicates coordinating interaction between zinc ion and HPC. The generation of ZnO nanoparticles in the HPC matrix proceeds in situ through the annealing of the gel phase at a temperature of 160°C. Identification of ZnO nanoparticles in the HPC matrix is done by using photoluminescence (PL), UV–Vis, and Raman spectroscopy. The films of ZnO/HPC nanocomposite are transparent in the visible light and show a higher energy value of absorption edge compared with ZnO in the bulk. Nanocrystalline films of ZnO were obtained by the calcination of ZnO/HPC nanocomposite at 500°C. ZnO films possess a good transparency for the visible light and high absorbance for UV light. Nanocrystallite sizes of ZnO particles were estimated from the X‐ ray lines broadening. The properties of ZnO layers were studied by the evaluation of PL, X‐ray investigation and atom force microscope (AFM) scanning, and the optical absorption edge. Copyright © 2008 John Wiley & Sons, Ltd.     

Combustion synthesis of calcium doped ZnO nanoparticles for the photocatalytic degradation of methylene blue dye

ZnO nanoparticles are one of the prominent photocatalysts for environmental applications due to its high redox ability, nontoxic and higher stability. This report explains the synthesis of ZnO nanoparticles by a simple solution combustion method using zinc nitrate hexahydrate as an oxidizing agent and incense stick powder as fuel at 400 °C. Several techniques were adopted for the characterization of the obtained product. X-ray diffraction (XRD) pattern shows that a lower concentration of fuel gives pure ZnO and a higher concentration of fuel results in calcium doped ZnO with a cubic phase having a crystallite size of 32–28 nm. UV–vis spectrum shows that as the fuel concentration increases, band gap decreases and reaches to 3.33 eV for 3 g of fuel. Spongy networks with many pores wereobserved in the scanning electron microscope (SEM) and transmission electron microscope (TEM) images showed the average particle size of Ca doped ZnO NPs is about 20 nm. Pure and Ca doped ZnO nanoparticles were examined for photocatalytic degradation of methylene blue (MB) dye under UV light irradiation. The results prove that Ca doped ZnO nanoparticles show good photocatalytic activity.     

Effect of the guest solvent molecules on preparation of different morphologies of ZnO nanomaterials from the [Zn2(1,4-bdc)2(dabco)] metal-organic framework

The host and the apohost framework of [Zn₂(1,4-bdc)₂(dabco)]?·?4DMF?·?½H₂O (1?·?4DMF?·?½H₂O) (1,4-bdc?=?1,4-benzenedicarboxylate and dabco?=?1,4-diazabicyclo[2.2.2]octane) were used for the preparation of ZnO nanomaterials. With calcination of the host framework of 1?·?4DMF?·?½H₂O, ZnO nanoparticles could be fabricated. By the same process on fully desolvated framework of 1, ZnO microrods composed of ZnO nanoparticles were formed. These results indicate with removal of the guest solvent from the pores of this metal-organic framework (MOF), nanoparticle agglomeration increases and the role of this MOF in preparation of ZnO nanoparticles was reduced.     

Spectroscopy of Single Dibenzoterrylene Molecules in para‐Dichlorobenzene

We study single dibenzoterrylene (DBT) molecules embedded in 1,4‐dichlorobenzene (para‐dichlorobenzene, pDCB) at 1.2 K. Due to the relatively low melting point of pDCB (53 °C), this host‐guest system can be easily prepared from the molten phase. Narrow linewidths, stable molecular lines and high saturation count rates of single DBT molecules were observed. For this reason, we consider this host‐guest system a promising candidate for the study of interactions of single molecules with other small objects such as waveguides or nanoparticles.     

Effect of ZnO on Photocatalytic Degradation of Rh B and Its Inhibition Activity for C. coli Bacteria

Russian Journal of Applied Chemistry - Zinc oxide (ZnO) nanoparticles have been synthesized by co-precipitation method. The structural properties like average crystallite size, lattice parameters,...