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Search Results: 1 - 10 of 1518 matches for " ZnO "
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Effect of Calcinations Temperature on Crystallography and Nanoparticles in ZnO Disk  [PDF]
Urai Seetawan, Suwit Jugsujinda, Tosawat Seetawan, Ackradate Ratchasin, Chanipat Euvananont, Chabaipon Junin, Chanchana Thanachayanont, Prasarn Chainaronk
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.29176
Abstract: We proposed a good calcinations condition of the ZnO disk to control the crystallography and nanoparticles in ZnO disk. The crystallography of precursor powder and disk powder were analyzed by the X-ray diffraction (XRD). The mean nanoparticles of ZnO disk was determinate by XRD results and observed by scanning electron microscope. The temperature ranges of 400℃ to 650℃ in air for 30 minutes were used calcinations ZnO disk. These temperature can be controlled the single phase, lattice parameters, unit cell volume, crystalline size, d-value, texture coefficient and bond lengths of Zn–Zn, Zn–O and O–O which correspond significantly the hexagonal crystal structure. The nanoparticles were small changed mean of 76.59 nm at the calcinations temperature range.
Growth and Electrical Properties of Doped ZnO by Electrochemical Deposition  [PDF]
Dewei Chu, Sean Li
New Journal of Glass and Ceramics (NJGC) , 2012, DOI: 10.4236/njgc.2012.21003
Abstract: In this work, pure and different metal ions doped ZnO thin films were obtained by a facile electrochemical deposition process. Different morphologies of ZnO, such as nanoplates, nanoparticles, as well as dense film can be obtained by doping Cu2+, In3+, and Al3+, respectively. Besides, the electrical properties of ZnO were also dependent on the doping ions. In this work, only pure ZnO shows resistive switching characteristics, indicating that the defects in ZnO is a key role in inducing resistive switching behaviour.
Coating of Medical-Grade PVC Material with ZnO for Antibacterial Application  [PDF]
Huaxiang Lin, Luyao Ding, Weihua Deng, Xuxu Wang, Jinlin Long, Qun Lin
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.34030
Abstract: The ZnO sol well-crystallized was prepared by the sol-gel method. The ZnO films were coated on medical-grade PVC surface by the improved organic-inorganic interfacial adhesion method. The physical and photocatalytic properties of the samples were characterized by XRD, SEM, DRS spectra and measured by the photodegradation reaction of Rho-damine B (RhB) and anti-bacteria for Escherichia coli (E. coli), respectively. The results show that pretreatment of PVC by the mix solution of THF-PVC helps to improve the amount and adhesion strength of ZnO suspension to PVC surface. The photocatalytic and antibacterial properties of the THF-ZnO/PVC film are better than that of the ZnO/PVC and neat PVC. Under UV irradiation, the THF-ZnO/PVC film shows the best antibacterial properties with 99% kill rate of bacteria.
Crystal Growth of ZnO Microneedles in Water Containing Microbubbles  [PDF]
Yomei Tokuda, Hiroaki Matsuki, Yoshikatsu Ueda, Hirokazu Masai, Toshinobu Yoko
New Journal of Glass and Ceramics (NJGC) , 2014, DOI: 10.4236/njgc.2014.43007
Microbubble technology is now available in a wide range of industrial fields. The liquid containing microbubbles possesses a large number of air-liquid interfaces, and also generates radicals during bubble collapse. Here, we synthesized ZnO powder to explore the potential of microbubbles as starting materials for the formation of crystalline micro- or nanoparticles. The bubbles facilitated the growth of ZnO microneedles in high yields, and enhanced the reaction by radicals generated on bubble collapsing.
Synthesis of Aluminum-doped Zinc Oxide Nanowires Hydrothermally Grown on Plastic Substrate  [PDF]
Concepción Mejía García, Elvia Díaz Valdés, Ana Ma. Paniagua Mercado, Arturo F. Méndez Sánchez, José A. Andraca Adame, Velumani Subramaniam, Josué Romero Ibarra
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B016
Abstract: We report the synthesis of undoped ZnO and Al-doped ZnO (ZnO:Al) nanowires grown using a two-step process: (a) preparation of the seed layer, and (b) growth of the nanostructures. In the first step,  10 mM solutions of zinc acetate dihydrate and 1-propanol were spin coated on polyethylene terephthalate  (PET) substrate at 2000 rpm by 30 s. Vertical nanowires were then grown by dipping the substrates in an equimolar solution of zinc nitrate hexahydrate and hexamethylenetetramine. As doping source, aluminum nitrate nonahydrate powders were added in the solution. In the solutions, Al doping concentrations were established as 0.5 At %, 1.0 At %, 2.0 At % and 3.0 At %, respectively. The hydrothermal process were carried out with a commercially microwave at 140 W power setting. The nanowires were characterized optically and morphologically. XRD patterns show the presence of ZnO, Zn(OH)2 and Zn6Al2O9. Scanning electron microscopy analysis showed that the size of ZnO nanowires was 50 nm in diameter. The undoped ZnO and ZnO:Al nanowires bandgap energy was obtained from optical transmission spectra.
Modification at Lattice Scale for an Optimized Optical Response of Alx(ZnO)1-x Nanostructures  [PDF]
Avanish Kumar Srivastava, Karuppanan Senthil, Melepurath Deepa, Ruchi Gakhar, Jai Shankar Tawale
World Journal of Nano Science and Engineering (WJNSE) , 2011, DOI: 10.4236/wjnse.2011.11003
Abstract: We report the systematic changes of nano-scaled features and optical properties in a promising transparent oxide material, namely, Alx (x = 0, 1, 2 and 5%) doped ZnO1-x (AZO). Electron microscopy investigations revealed the alterations at lattice scale depending on the presence of Al-content in ZnO nanostructures. Lattice spacings of 0.26 and 0.28 nm oriented along the (0002) and (10 0) planes, respectively, were attributed to euhedral-and facetted-structures of hexagonal-ZnO. The AZO samples were further characterized by XRD, SEM, UV-vis spectrophotometry, Raman spectroscopy and photoluminescence studies. It has been shown that at a dopant concentration of 2%Al in ZnO, an optimal balance could be achieved between microstructure and optical properties.
Antibacterial Zinc Oxide Nanoparticle Coating of Polyester Fabrics  [PDF]
Claudia Rode, Michael Zieger, Ralf Wyrwa, Susanne Thein, Cornelia Wiegand, Monika Weiser, Andreas Ludwig, Dirk Wehner, Uta-Christina Hipler
Journal of Textile Science and Technology (JTST) , 2015, DOI: 10.4236/jtst.2015.12007
Abstract: Polyester knitted fabrics have been equipped with antibacterial properties by coating with aqueous suspensions of zinc oxide (ZnO) with different particle diameters. It can be shown that the antibacterial efficacy against Staphylococcus aureus and Klebsiella pneumonia and the permanence of the coating after defined washing cycles depends on the composition of the ZnO dispersion. To improve the wettability of the textile, the combustion chemical vapor deposition (CCVD) is used to generate a hydrophilic nano layer of a hydroxyl terminated silicon network on the surface of the textiles. The comparison of CCVD-treated and untreated polyester samples does not show differences in the antibacterial activity. The influence of the coating in terms of amount and particle size of ZnO on the viability and proliferation of 3T3 mouse fibroblast cells is examined. A particle content of a maximum of 20 μg ZnO/cm2 is found to be cytocompatible for coating of textiles.
Investigation of Photocatalytic Degradation of Methyl Orange by Using Nano-Sized ZnO Catalysts  [PDF]
Changchun Chen, Jiangfeng Liu, Ping Liu, Benhai Yu
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.11002
Abstract: Nano-sized ZnO catalysts were prepared by a direct precipitation method under the optimal conditions (cal-cination of precursors at 550?C for 120 min). The as-synthesized ZnO catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-Vis spectroscopy. The photocatalytic prop-erties of ZnO nanoparticles were investigated via methyl orange (MO) as a model organic compound under UV light irradiation. The influence of operating parameters on MO degradation including the amount of ZnO catalysts, pH value of solutions, and the photodegradation temperature was thoroughly examined. In addition, the kinetic process of photocatalytic degradation of MO using nano-sized ZnO catalyst was also examined, and the degradation of MO follow the first order kinetics.
Optical and Structural Properties of ZnO Thin Films Fabricated by Sol-Gel Method  [PDF]
Ziaul Raza Khan, Mohd Shoeb Khan, Mohammad Zulfequar, Mohd Shahid Khan
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.25044
Abstract: Highly oriented and transparent ZnO thin films have been fabricated on ultrasonically cleaned quartz substrates by the sol-gel technique. X-ray diffraction, UV-VIS, FTIR, photoluminescence and SEM are used to characterize ZnO thin films. X-ray diffraction study show that all the films prepared in this work have hexagonal wurtzite structure, with lattice constants a = b = 3.260 Å, c = 5.214 Å. The optical band gap energy of the thin films is found to be direct allowed transition ~3.24 eV. The FTIR spectrum of the film has the characteristics ZnO absorption band at 482 cm?1. The photoluminescence spectrum of the samples has an UV emission peak centred at 383 nm with broad band visible emission centred in the range of 500 - 600 nm.
Hydrogen Incorporation in Undoped ZnO Nanoparticles  [PDF]
Suhendro Purbo Prakoso
World Journal of Condensed Matter Physics (WJCMP) , 2011, DOI: 10.4236/wjcmp.2011.14019
Abstract: Zinc Oxide nanoparticles in the size range of ~18 - 23 nm are prepared using wet chemical method. Hydrogen concentration in the samples was obtained by drying the precipitate at various temperatures. XRD pattern showed a single phase wurzite structure for ZnO nanoparticles. Average crystallite sizes and lattice parameters determined from XRD pattern showed a gradual increase with increasing dry temperature, while the lattice strain showed the opposite direction. Optical studies revealed the optical gap ranging from 3.05 - 3.24 eV. Hydrogen incorporation in the specimen was studied using infrared absorption measurement. Infrared absorption measurements revealed six hydrogen-related local vibrational modes in the wave number range from 2800 to 3600 cm–1. To remove hydrogen, some samples were annealed up to 800°C. Infrared absorption measurements showed that the local vibational modes disappeared. This shows that the observed local vibrational modes are due to the presence of hydrogen. The results of XRD and optical studies will be correlated with the results obtained from infrared absorption measurements.
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