Properties Of ZnO Nanopowders Research Articles

Influence of Aluminum Cations on the Structural, Optical and Electrical Properties of ZnO Nanopowder

Influence of Aluminum Cations on the Structural, Optical and Electrical Properties of ZnO Nanopowder

Photoluminescence in gas of (Ca) Mg-doped ZnO nanopowders

The researches structural, morphological and photoluminescent properties of zinc oxide nanopowders doped by Mg and Ca obtained using pulsed laser reactive technology is carried out. Electron microscopy and X-ray diffractometry were conducted to determine the structure, shape, and size of the nanoparticles. Investigation of the peculiarities of photoluminescence in different ambient of Ca- and Mg-doped ZnO nanopowders was carried out. The decomposition of luminescence spectra into elementary bands shows the presence of four elementary peaks. The most intense two bands in visible region which are sensitive to ambient gas, a blue-band centered at 430 nm and stronger in intensity the band around 520 nm. The influence of the impurity and the different ambient on the redistribution of elementary luminescence bands intensities was investigated. That can be used in the gas sensors. The visible emissions observed may be ascribed to the intrinsic defects in particular oxygen vacancies. Large surface area and surface defects are the most important variables to determine the sensory properties of ZnO nanopowders and making them are the most favorable material for gas sensors.

THE INVESTIGATION OF VARIATIONS IN OPTICAL PROPERTIES DEPENDING ON SINTERING TEMPERATURE OF Ni:ZNO NANO POWDERS

In this study, Ni:ZnO nano powders were produced by the sol-gel calcination method to investigate and improve the interaction between sintering temperature and optical properties. ZnO based nano-ceramic materials with superior properties which can be used in several scientific researches and high technology applications and can be easily synthesized were produced by this method. The effect of Ni doping on the optical properties of ZnO nanopowders was investigated through spectrophotometric measurements. The optical band gaps of the samples were calculated from the diffuse reflectance curves using Kubelka-Munk function. It was observed that E g values of the samples changed depending on the Ni dopant and sintering temperature. As a result of the investigations, it was determined that Ni doping and different sintering temperature have significant effects on the optical properties of ZnO nano powders, and the produced samples can be used in high temperature conductive electrode applications, optoelectronic devices, and sensor production.

Effect of Ag + Co doping on the antibacterial properties of ZnO nanopowders synthesized using combustion method

The present study reports the antibacterial activities of undoped and Ag (2 at.%) + Co (5 at.%) doped ZnO nanopowders synthesized using combustion method. The synthesized particles have been tested to find the effect of doping on the antibacterial activities against two different pathogens namely Shigella flexneri and Bacillus Cereus. Further structural, morphological, chemical, compositional and optical properties were studied using X ray diffractometer (XRD), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy and Photoluminescence spectroscopy, respectively. The results reveal that Ag + Co doped ZnO shows better antibacterial activity against both the tested bacterial strains when compared with bare ZnO. The possible mechanism for the antibacterial activity of Ag + Co doped ZnO is reported

Preparation of ZnO Nanopowders by One-Step Hydrothermal Synthesis

In the paper, ZnO nanopowders were synthesized by using zinc acetate and sodium hydroxide as raw materials. The influences of different soft templates and synthesis temperature on the properties of ZnO nanopowders were investigated. The results showed that: when using the polyethylene glycol (PEG (400)) or polyvinyl alcohol (PVA) as soft template, the ZnO nanoparticles with the diameter about 100nm were obtained, whereas the ZnO nanorods which the length and diameter were 300nm and 150nm respectively were obtained without soft template. When the synthesis temperature was 220°C and 70°C, the ZnO nanorods were obtained. When the temperature was 100°C, the ZnO nanosheets were produced, and the length, width and thickness of ZnO nanosheets were about 800 nm, 500nm and 80nm, respectively. When the temperature was 90°C, the ZnO nanosheets composed with nanorods were prepared.

One-Step Hydrothermal Synthesis and Characterization of ZnO Nanopowders

In the paper, ZnO nanopowders were synthesized by one-step hydrothermal synthesis using zinc acetate and sodium hydroxide as raw materials. The influences of molar concentration of NaOH and synthesis temperature on the properties of ZnO nanopowders were investigated. XRD and FSEM were used to characterize ZnO nanopowders. The results showed that; when the molar concentration of NaOH was 0.05 mol/L, 1mol/L and 2mol/L, ZnO micrometer powders were obtained. When the molar concentration of NaOH was 4mol/L, ZnO nanorods or nanosheets were obtained with different reaction temperature. When the temperature was 220°C, ZnO nanorods with the length of 500nm and diameter of 100nm, were synthesised. Pure ZnO nanopowders can be obtained at lower temperature of 100°C by using one-step hydrothermal synthesis. When the synthesis temperature was 100°C and the molar concentration of NaOH was 4mol/L, ZnO nanosheets were produced. The length, width and thickness of ZnO nanosheets were about 800 nm, 500nm and 80nm, respectively.

Structure and Properties of Doped ZnO Nanopowders Synthesized by Methanol Alcoholysis Method

Pured ZnO, Al doped ZnO and Al-In co-doped ZnO nanopowders were synthesized by the methanol alcoholysis method at 130 °C. Structure, morphology and optical properties of ZnO nanopowders were characterized using X-ray diffraction, Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Photoluminescence (PL) spectra. The results show that ZnO nanopowders can be obtained in methanol solution at low temperature (130 °C). TEM images show that Al doped ZnO nanocrystals grow along the [002] axis quicker than other axes. FTIR spectra show that ZnO nanocrystals synthesized by the methanol alcoholysis include a little organic impurity. PL spectrums reveal that pure ZnO and doped ZnO nanocrystals have a blue band emission at 440 nm and a green band emission at 520 nm and 530 nm, respectively. Compared with the pure ZnO nanocrystal, the Al doping improves the luminescent properties.

The seeding effect on the microstructure and photocatalytic properties of ZnO nano powders

Nano sized ZnO powders, with suitable amount of TiO 2 (P25), have been successfully synthesized via a novel modified hydrothermal method by using zinc acetate. Titania nano powder plays an important role in fabrication of ZnO nano structure. The structure and morphology of the product were characterized by X-ray diffraction and scanning electron microscopy, which show different morphologies and particle sizes. Photocatalytical properties of the product exhibit strong improvement in the reactivity of seeded powders. These powders have better properties because of coupling effect of semiconductors, small powder size and reduced recombination of electron-hole in the surface of a catalyst.