Synthesis and surface modification of zno nanoparticles

ZnO nanoparticles have been synthesized by precipitation method from Zinc nitrate. The powder was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected-area electron diffraction, UV-vis optical absorption, and photoluminescence spectroscopy analyses. XRD patterns showed that ZnO nanoparticles have hexagonal unit cell structure. SEM and TEM pictures reveal the morphology and particle size of prepared ZnO nanoparticles. The UV-vis absorption spectrum shows an absorption band at 355 nm due to ZnO nanoparticles. The photoluminescence spectrum exhibits two emission peaks one at 392 nm corresponding to band gap excitonic emission and another located at 520 nm due to the presence of singly ionized oxygen vacancies. The synthesis method has potential for application in manufacturing units due to ease processing and more economical reagents.

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Synthesis, Characterization, and Spectroscopic Properties of ZnO Nanoparticles

Nanoparticles of zinc oxide (ZnO) are increasingly recognized for their utility in biological applications. In this study, the high-energy ball milling (HEBM) technique was used to produce nanoparticles of ZnO from its microcrystalline powder. Four samples were ball milled for 2, 10, 20, and 50 hours, respectively. The structural and optical modifications induced in the 'as synthesized' nanomaterials were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and photoluminescence emission spectra (PL). SEM and TEM results show a gradual decrease in particle size from around 600 to ∼30 nm, with increased milling time. The initial microstructures had random shapes, while the final shape became quite spherical. XRD analysis showed ZnO in a hexagonal structure, broadening in the diffracted peaks and going from larger to smaller particles along with a relaxation in the lattice constant c. The value of c was found to increase from 5.204 to 5.217 A with a decrease in particle size (600 to ∼30 nm). PL result showed a new band at around 365 nm, whose intensity is found to increase as the particles size decreases. These remarkable structural and optical modifications induced in ZnO nanoparticles might prove useful for various applications. The increase in c value is an important factor for increasing the antibacterial effects of ZnO, suggesting that the HEBM technique is quite suitable for producing these nanoparticles for this purpose.

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High-energy ball milling technique for ZnO nanoparticles as antibacterial material.

Preparation, characterization and application of Fe3O4/ZnO core/shell magnetic nanoparticles

Synthesis and characterization of PMMA grafted ZnO nanoparticles

Varistors based on ZnO–lead zinc borosilicate glass were prepared from tetrapod ZnO nanopowders, every one of which had four needle-like legs and each one was about 20 nm or less in diameter and from several hundreds of nanometers to several micrometers in length by the method of direct co-sintering synthesis of oxides instead of adding amorphous lead zinc borosilicate frit. The compact green disks were conventionally sintered in air for 2 h at a temperature of 900–1170 °C. The varistors with nonlinear coefficient α=38.7 and leakage current IL=1.7 μA were obtained. The results showed that the sintering temperature was lowered to 900 °C, and there was very little influence of the sintering temperature on the nonlinear coefficient α at a range 900–1170 °C.

Wu Run

Papers

Preparation of ZnO-glass varistor from tetrapod ZnO nanopowders