Effect of temperature on structural, optical and photoluminescence studies on ZnO nanoparticles synthesized by the standard co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Raj, K. Pradeev [Research and Development Centre, Bharathiar University, Coimbatore 641046, Tamil Nadu (India); Department of Physics, CSI College of Engineering, Ooty 643215, Tamil Nadu (India); Sadayandi, K. [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivagangai 630003, Tamil Nadu (India)

2016-04-15

This present study brings the synthesis of Zinc oxide (ZnO) nanoparticles (NPs) by the standard aqueous chemical route technique. The impact of calcination temperature on the extent of the ZnO nanoparticles is studied for its lattice constraints. X-ray diffraction (XRD) affirms the hexagonal Wurtzite structure of the synthesized ZnO nanoparticles. From the Williamson–Hall (W–H) plot, positive slope is inferred for pure and calcined ZnO NPs and confirms the presence of tensile strain. From the SEM images it is found that the crystallinity enhances with calcination temperature. From the optical studies, it is found that the band gap energy decreases with improved transmission. The Photoluminescence (PL) spectrum reveals the UV emission is strong near the band-edge. The emission peaks around 400–480 nm result in blue emission and the peaks around 540–560 nm result in green emission. Decrease in band gap energy and enhancement in PL studies reveal the red shift of the calcined ZnO exhibiting solid quantum confinements.

Electrochemical characteristics of coated steel with poly(N-methyl pyrrole) synthesized in presence of ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Mahmoudian, M.R., E-mail: M_R_mahmoudian@yahoo.com [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Masjed-Soleiman Branch, Islamic Azad University, Masjed-Soleiman (Iran, Islamic Republic of); Basirun, W.J.; Alias, Y. [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Khorsand Zak, A. [Low Dimensional Materials Research Center, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-10-31

Poly(N-methyl pyrrole) (PMPy) coating was electrodeposited on steel substrates in mixed electrolytes of dodecyl benzene sulphonic acid with oxalic acid in the absence and the presence of ZnO nanoparticles (NPs). The morphology and compositions were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy and Energy-dispersive X-ray spectroscopy. Electrode/coating/electrolyte system was studied by Electrochemical Impedance Spectroscopy. The comparison between the pore resistance (R{sub po}) of synthesized PMPy in the absence and presence of ZnO NPs indicated that the existence of ZnO increased the R{sub po} of the coating. The FESEM micrographs indicated that the size of micro-spherical grains in the morphology of PMPy is significantly reduced and the surface area of PMPy is increased with the presence of ZnO NPs. The increase of the ability to interact with the ions liberated during the corrosion reaction of steel and the increase of the rate probability for the occurrence of cathodic reduction of oxygen on the PMPy with the increase of the surface area can be considered as reasons for improvement of protective properties of synthesized PMPy in the presence of ZnO NPs.

Microwave assisted synthesis of ZnO nanoparticles for lighting and dye removal application

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Kumar, Vijay, E-mail: vijays_phy@rediffmail.com [Department of Physics, University of Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Gohain, M. [Department of Chemistry, University of Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Som, S.; Kumar, Vinod [Department of Physics, University of Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Bezuindenhoudt, B.C.B. [Department of Chemistry, University of Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Swart, Hendrik C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of Free State, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa)

2016-01-01

In this study, we report on the synthesis of ZnO nanoparticles (NPs) via the microwave-assisted technique. The as-synthesized ZnO nanoparticles were annealed at 500 °C for three hours. The ZnO NPs were characterized by X-ray diffraction (XRD) and scanning electron microscopic techniques. XRD results confirmed the formation of as-synthesized ZnO powder oriented along the (101) direction. The Kubelka–Munk function has been employed to determine the band gap of the ZnO powder. ZnO powder has been studied by photoluminescence (PL) before and after annealing to identify the emission of defects in the visible range. The intensity of the PL emission has decreased after annealing. The synthesized ZnO samples were also studied for methyl orange dye removal from waste water. It has been found that the as-synthesized ZnO shows better adsorption behaviour as compared to the annealed sample.

Magnetic properties of sol-gel synthesized C-doped ZnO nanoparticles

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Dung, Nguyen Duc, E-mail: dung.nguyenduc@hust.edu.vn [Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology, No.1 Dai Co Viet, Hanoi (Viet Nam); Son, Cao Thai; Loc, Pham Vu; Cuong, Nguyen Huu; Kien, Pham The; Huy, Pham Thanh [Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology, No.1 Dai Co Viet, Hanoi (Viet Nam); Ha, Ngo Ngoc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet, Hanoi (Viet Nam)

2016-05-25

ZnO doping with Carbon (C-doped ZnO) materials were prepared by sol-gel technique following with a heat treatment process. Single phase of Wurtzite crystal structure of ZnO was concluded via x-ray diffraction (XRD) with a large amount of excess C tracking by energy dispersive X-ray spectroscopy (EDX) analysis. Two types of ZnO crystals (twinning particles) with different grain sizes and shapes were identified via scanning electron microscopy (FE-SEM). The first type has a smaller grain size of about 20 nm and hexagonal shape. And the second type has a larger grain size of about 80–120 nm and round shape. C substitutions of both Zn and O sites to form C–O and C–Zn bonds were conclusively confirmed via x-ray photoelectron spectroscope (XPS). Experimental evidences for the co-existence of different ferromagnetic phases in the materials are reported and discussed. Two Curie points at high temperatures (>500 °C) are presented. A metamagnetic transition was observed at magnetic field H = 19.2 kOe which was related to the co-existence of ferromagnetic phases. These involve in the formation of twinning C-doped ZnO nanoparticles. - Highlights: • Formation of sol-gel prepared single phase wurtzite ZnO nanoparticles. • Two morphological C-doped ZnO nanoparticles of different grain sizes. • The room temperature ferromagnetism. • An abnormal metamagnetic transition at magnetic field H = 19.2 kOe. • Two different Curie points (T{sub C}) at 500–600 °C.

ZnO doped SnO2 nanoparticles heterojunction photo-catalyst for environmental remediation

International Nuclear Information System (INIS)

Lamba, Randeep; Umar, Ahmad; Mehta, S.K.; Kansal, Sushil Kumar

2015-01-01

ZnO doped SnO 2 nanoparticles were synthesized by facile and simple hydrothermal technique and used as an effective photocatalyst for the photocatalytic degradation of harmful and toxic organic dye. The prepared nanoparticles were characterized in detail using different techniques for morphological, structural and optical properties. The characterization results revealed that the synthesized nanoparticles possess both crystal phases of tetragonal rutile phase of pure SnO 2 and wurtzite hexagonal phase of ZnO. In addition, the nanoparticles were synthesized in very high quantity with good crystallinity. The photocatalytic activity of prepared nanoparticles was evaluated by the photocatalytic degradation of methylene blue (MB) dye. Detailed photocatalytic experiments based on the effects of irradiation time, catalyst dose and pH were performed and presented in this paper. The detailed photocatalytic experiments revealed that the synthesized ZnO doped SnO 2 nanoparticles heterojunction photocatalyst exhibit best photocatalytic performance when the catalyst dose was 0.25 g/L and pH = 10. ZnO doped SnO 2 nanoparticles heterojunction photocatalyst was also compared with commercially available TiO 2 (PC-50), TiO 2 (PC-500) and SnO 2 and interestingly ZnO doped SnO 2 nanoparticles exhibited superior photocatalytic performance. The presented work demonstrates that the prepared ZnO doped SnO 2 nanoparticles are promising material for the photocatalytic degradation of organic dyes and toxic chemicals. - Highlights: • Synthesis of well-crystalline ZnO-doped SnO 2 nanoparticles. • Excellent morphological, crystalline and photoluminescent properties. • Efficient environmental remediation using ZnO-doped SnO 2 nanoparticles.

Low Temperature Ferromagnetism and Optical Properties of Fe Doped ZnO Nanoparticles Synthesized by Sol-Gel Method

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B. Sathya

2017-06-01

Full Text Available In this present investigation, pure and Fe doped Zinc oxide nanoparticles were successfully synthesized by sol gel method.The structural and optical properties were examined by using X-ray diffraction (XRD, Scanning electron microscope (SEM, Transmission electron microscope (TEM, Ultraviolet spectroscopy and Photoluminescence (PL techniques.The structural characterization of XRD analysis confirmed the phase purity of the samples and crystallite size can be decreased with increasing doping concentrations.SEM image show that nanoparticles in spherical shape. The optical band gap calculated through UV-visible spectroscopy is found to be increasing from 3.48 to 3.57eV. TEM analysis depicted the crystallinity of nanoparticles prepared and chemical composition conformed the EDAX analysis. The PL spectra reveal that, Fe doped ZnO exhibit a decrease in intensity of the band edge emission peak while the intensity of the deep level emission peak increases.The enhancement of low temperature ferromagnetism in ZnO: Fe was achieved.

Solar-assisted synthesis of ZnO nanoparticles using lime juice: a green approach

Science.gov (United States)

Hinge, Shruti P.; Pandit, Aniruddha B.

2017-12-01

Zinc oxide (ZnO) nanoparticles are those nanoparticles which have been synthesized in various morphologies and shapes. Their size and shape dependent properties and their applications in vivid sectors of science and technology make them interesting to synthesize. Present work reports a green method for ZnO nanoparticle synthesis using lime juice and sunlight. ZnO nanoparticles were also synthesized by conventionally used methods like heating, stirring or no heating and/or stirring. The nanoparticles were characterized using different techniques like UV-vis spectroscopy, scanning electron microscopy (SEM), x-ray diffraction (XRD) and dynamic light scattering (DLS). Thermo gravimetric analysis (TGA) was also carried out for the intermediate product to select the calcination temperature. Stoichiometric study reveals that the intermediate product formed is zinc citrate dihydrate. The synthesized calcined nanoparticles have good crystallinity, uniform shape, and high purity and were in the size range of 20-30 nm. These nanoparticles formed agglomerates of various shapes in the size range of 200-750 nm. This process is ecofriendly and is amiable for easy scale up.

Dynamic recovery and optical properties changes in He-implanted ZnO nanoparticles

International Nuclear Information System (INIS)

Lee, J.-K.; Harriman, T.A.; Lucca, D.A.; Jung, H.S.; Ryan, D.B.; Nastasi, M.

2007-01-01

A study of the effects of ion-implanted He + on the photoluminescence (PL) of ZnO nanoparticles is presented. This investigation is motivated by the need to further understand the effects of damage resulting from the implantation process on the luminescence response of the nanoparticles. ZnO nanoparticles were synthesized by reacting zinc acetate with lithium hydroxide. The nanoparticle suspension was then dip coated on SiO 2 substrates producing thin films of ZnO nanoparticles, which were then implanted with He + ions at either room temperature or 400 deg. C. Following implantation, the PL spectrum of the ZnO nanoparticles was investigated and compared to that obtained from He-implanted bulk ZnO. Change in the overall luminescence efficiency was found to depend on both the size of the nanoparticles and the implantation temperature, and is attributed to the dynamic recovery of collision cascades in the ZnO nanoparticles. In addition, a comparison of He + -implanted ZnO nanoparticles with He + -implanted ZnO single crystals indicates that the origin of the green luminescence occurring from the ZnO nanoparticles is near-surface complex defects

Green method for producing hierarchically assembled pristine porous ZnO nanoparticles with narrow particle size distribution

International Nuclear Information System (INIS)

Escobedo-Morales, A.; Téllez-Flores, D.; Ruiz Peralta, Ma. de Lourdes; Garcia-Serrano, J.; Herrera-González, Ana M.; Rubio-Rosas, E.; Sánchez-Mora, E.; Olivares Xometl, O.

2015-01-01

A green method for producing pristine porous ZnO nanoparticles with narrow particle size distribution is reported. This method consists in synthesizing ZnO 2 nanopowders via a hydrothermal route using cheap and non-toxic reagents, and its subsequent thermal decomposition at low temperature under a non-protective atmosphere (air). The morphology, structural and optical properties of the obtained porous ZnO nanoparticles were studied by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and nitrogen adsorption–desorption measurements. It was found that after thermal decomposition of the ZnO 2 powders, pristine ZnO nanoparticles are obtained. These particles are round-shaped with narrow size distribution. A further analysis of the obtained ZnO nanoparticles reveals that they are hierarchical self-assemblies of primary ZnO particles. The agglomeration of these primary particles at the very early stage of the thermal decomposition of ZnO 2 powders provides to the resulting ZnO nanoparticles a porous nature. The possibility of using the synthesized porous ZnO nanoparticles as photocatalysts has been evaluated on the degradation of rhodamine B dye. - Highlights: • A green synthesis method for obtaining porous ZnO nanoparticles is reported. • The obtained ZnO nanoparticles have narrow particle size distribution. • This method allows obtaining pristine ZnO nanoparticles avoiding unintentional doping. • A growth mechanism for the obtained porous ZnO nanoparticles is proposed

Sol-gel synthesized ZnO for optoelectronics applications: a characterization review

Science.gov (United States)

Harun, Kausar; Hussain, Fayaz; Purwanto, Agus; Sahraoui, Bouchta; Zawadzka, Anna; Azmin Mohamad, Ahmad

2017-12-01

The rapid growth in green technology has resulted in a marked increase in the incorporation of ZnO in energy and optoelectronic devices. Research involving ZnO is being given renewed attention in the quest to fully exploit its promising properties. The purity and state of defects in the ZnO system are optimized through several modifications to the synthesis conditions and the starting materials. These works have been verified through a series of characterizations. This review covers the essential characterization outcomes of pure ZnO nanoparticles. Emphasis is placed on recent techniques, examples and some issues concerning sol-gel synthesized ZnO nanoparticles. Thermal, phase, structural and morphological observations are combined to ascertain the level of purity of ZnO. The subsequent elemental and optical characterizations are also discussed. This review would be the collective information and suggestions at one place for investigators to focus on the best development of ZnO-based optical and energy devices.

Green method for producing hierarchically assembled pristine porous ZnO nanoparticles with narrow particle size distribution

Energy Technology Data Exchange (ETDEWEB)

Escobedo-Morales, A., E-mail: alejandro.escobedo@correo.buap.mx [Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Téllez-Flores, D.; Ruiz Peralta, Ma. de Lourdes [Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Garcia-Serrano, J.; Herrera-González, Ana M. [Centro de Investigaciones en Materiales y Metalurgia, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca Tulancingo Km 4.5, Pachuca, Hidalgo (Mexico); Rubio-Rosas, E. [Centro Universitario de Vinculación y Transferencia de Tecnología, Benemérita Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico); Sánchez-Mora, E. [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Postal J-48, 72570 Puebla, Pue. (Mexico); Olivares Xometl, O. [Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue. (Mexico)

2015-02-01

A green method for producing pristine porous ZnO nanoparticles with narrow particle size distribution is reported. This method consists in synthesizing ZnO{sub 2} nanopowders via a hydrothermal route using cheap and non-toxic reagents, and its subsequent thermal decomposition at low temperature under a non-protective atmosphere (air). The morphology, structural and optical properties of the obtained porous ZnO nanoparticles were studied by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and nitrogen adsorption–desorption measurements. It was found that after thermal decomposition of the ZnO{sub 2} powders, pristine ZnO nanoparticles are obtained. These particles are round-shaped with narrow size distribution. A further analysis of the obtained ZnO nanoparticles reveals that they are hierarchical self-assemblies of primary ZnO particles. The agglomeration of these primary particles at the very early stage of the thermal decomposition of ZnO{sub 2} powders provides to the resulting ZnO nanoparticles a porous nature. The possibility of using the synthesized porous ZnO nanoparticles as photocatalysts has been evaluated on the degradation of rhodamine B dye. - Highlights: • A green synthesis method for obtaining porous ZnO nanoparticles is reported. • The obtained ZnO nanoparticles have narrow particle size distribution. • This method allows obtaining pristine ZnO nanoparticles avoiding unintentional doping. • A growth mechanism for the obtained porous ZnO nanoparticles is proposed.

Synthesis, effect of capping agents, structural, optical and photoluminescence properties of ZnO nanoparticles

International Nuclear Information System (INIS)

Singh, A.K.; Viswanath, V.; Janu, V.C.

2009-01-01

Zinc oxide nanoparticles were synthesized using chemical method in alcohol base. During synthesis three capping agents, i.e. triethanolamine (TEA), oleic acid and thioglycerol, were used and the effect of concentrations was analyzed for their effectiveness in limiting the particle growth. Thermal stability of ZnO nanoparticles prepared using TEA, oleic acid and thioglycerol capping agents, was studied using thermogravimetric analyzer (TGA). ZnO nanoparticles capped with TEA showed maximum weight loss. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for structural and morphological characterization of ZnO nanoparticles. Particle size was evaluated using effective mass approximation method from UV-vis spectroscopy and Scherrer's formula from XRD patterns. XRD analysis revealed single crystal ZnO nanoparticles of size 12-20 nm in case of TEA capping. TEA, oleic acid and thioglycerol capped synthesized ZnO nanoparticles were investigated at room temperature photoluminescence for three excitation wavelengths i.e. 304, 322 and 325 nm, showing strong peaks at about 471 nm when excited at 322 and 325 nm whereas strong peak was observed at 411 for 304 nm excitation.

Sea-Urchin-Like ZnO Nanoparticle Film for Dye-Sensitized Solar Cells

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Cheng-Wen Ma

2015-01-01

Full Text Available We present novel sea-urchin-like ZnO nanoparticles synthesized using a chemical solution method. Solution approaches to synthesizing ZnO nanostructures have several advantages including low growth temperatures and high potential for scaling up. We investigated the influence of reaction times on the thickness and morphology of sea-urchin-like ZnO nanoparticles, and XRD patterns show strong intensity in every direction. Dye-sensitized solar cells (DSSCs were developed using the synthesized ZnO nanostructures as photoanodes. The DSSCs comprised a fluorine-doped tin oxide (FTO glass with dense ZnO nanostructures as the working electrode, a platinized FTO glass as the counter electrode, N719-based dye, and I-/I3-liquid electrolyte. The DSSC fabricated using such nanostructures yielded a high power conversion efficiency of 1.16% with an incident photo-to-current efficiency (IPCE as high as 15.32%. Electrochemical impedance spectroscopy was applied to investigate the characteristics of DSSCs. An improvement in the electron transport in the ZnO photoanode was also observed.

Direct Precipitation and Characterization of ZnO Nanoparticles

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A. H. Moharram

2014-01-01

Full Text Available ZnO nanoparticles are prepared through hydrolysis and condensation of zinc acetate dihydrate by potassium hydroxide in alcoholic medium at low temperatures. Thermal gravimetric analysis (TGA of the precursor is made in order to specify the temperature range over which the weight loss and thermal effect are significant. X-ray diffraction of the as-prepared specimens shows that the hexagonal (a=3.2459 Å, c=5.1999 Å structure is the predominant crystallographic structure. According to Scherer’s formula, the average size of the nanoparticles is 22.4 ± 0.6 nm. The structural properties of the synthesized ZnO nanoparticles have been confirmed using the TEM micrographs. The optical energy gap of the ZnO nanoparticles, as obtained from applying Tauc’s equation, is equal to 3.52 eV, which is higher than that of the bulk material. Absorption peak of the as-prepared sample is 298 nm which is highly blue shifted as compared to the bulk (360 nm. Large optical energy gap and highly blue shifted absorption edge confirm that the prepared ZnO nanoparticle exhibits strong quantum confinement effect.

Influence of solvents on the changes in structure, purity, and in vitro characteristics of green-synthesized ZnO nanoparticles from Costus igneus

Science.gov (United States)

Nandhini, G.; Suriyaprabha, R.; Maria Sheela Pauline, W.; Rajendran, V.; Aicher, Wilhelm Karl; Awitor, Oscar Komla

2018-05-01

The present study is intended to produce high-purity zinc oxide nanoparticles from the leaves of Costus igneus and zinc acetate precursor via sustainable methods by the tribulation with three different solvents (hot water, methanol, and acetone) for the extraction of plant compounds. While examining the physico-chemical characteristics of ZnO nanoparticles incurred by the catalysis of plant bioactive compounds extracted from different solvents, the hot water extract-based green synthesis process yields higher purity (99.89%) and smaller particle size (94 nm) than other solvents. The optimization of the solvents used for the green synthesis of nanoparticles renders key identification in appropriate extraction of bioactive compounds suitable for the nucleation/production of nanoparticles in addition to annealing temperature. The impregnable usage of ZnO nanoparticles in clinical applications is further confirmed based on the treatment of particles (1-10 mg ml-1) against Gram-positive (S. aureus and S. epidermis) and Gram-negative bacteria (E. coli and K. pneumoniae) with respect to their growth inhibition. An in-force growth inhibition against particular S. aureus and S. epidermis imparted by the low concentration of ZnO nanoparticles signifies the utilization and consumption of green-synthesized high-purity nanoparticles for therapeutic and cosmetic applications.

Antitubercular activity of ZnO nanoparticles prepared by solution combustion synthesis using lemon juice as bio-fuel.

Science.gov (United States)

Gopala Krishna, Prashanth; Paduvarahalli Ananthaswamy, Prashanth; Trivedi, Priyanka; Chaturvedi, Vinita; Bhangi Mutta, Nagabhushana; Sannaiah, Ananda; Erra, Amani; Yadavalli, Tejabhiram

2017-06-01

In this study, we report the synthesis, structural and morphological characteristics of zinc oxide (ZnO) nanoparticles using solution combustion synthesis method where lemon juice was used as the fuel. In vitro anti-tubercular activity of the synthesized ZnO nanoparticles and their biocompatibility studies, both in vitro and in vivo were carried out. The synthesized nanoparticles showed inhibition of Mycobacterium tuberculosis H37Ra strain at concentrations as low as 12.5μg/mL. In vitro cytotoxicity study performed with normal mammalian cells (L929, 3T3-L1) showed that ZnO nanoparticles are non-toxic with a Selectivity Index (SI) >10. Cytotoxicity performed on two human cancer cell lines DU-145 and Calu-6 indicated the anti-cancer activity of ZnO nanoparticles at varied concentrations. Results of blood hemolysis indicated the biocompatibility of ZnO nanoparticles. Furthermore, in vivo toxicity studies of ZnO nanoparticles conducted on Swiss albino mice (for 14days as per the OECD 423 guidelines) showed no evident toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of solvent medium on the structural, morphological and optical properties of ZnO nanoparticles synthesized by the sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Ungula, J., E-mail: ungulaj@qwa.ufs.ac.za; Dejene, B.F.

2016-01-01

ZnO nanoparticles were synthesized using a sol–gel method. The effect of solvent medium on the structural, morphological and optical properties of ZnO nanoparticles were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL), UV–vis spectroscopy (UV–vis) and Energy-dispersive X-ray spectroscopy ( EDS). The XRD patterns showed single phase hexagonal structure. The crystallite size of as prepared ZnO nanoparticles was found to decrease from 28.1 nm to 10.8 nm with the increase in volume ratio of ethanol in the solvent as peak intensities and sharpness increase with corresponding increase in volume ratio of water. SEM micrographs showed that samples prepared in water medium are fairly spherical which turned to tiny rods with increasing volume ratios of ethanol. A sharp ultraviolet (UV) emission peak centred about 385 nm and a broad green–yellow emission at about 550 nm are observed with PL measurements. The band gap of ZnO decreased from 3.31 to 3.17 eV with an increase in the ethanol composition in the solvent, implying that the optical properties of these materials are clearly affected by the synthesis medium.

Enhanced antimicrobial activity in biosynthesized ZnO nanoparticles

Science.gov (United States)

Kumari, Niraj; Kumari, Priti; Jha, Anal K.; Prasad, K.

2018-05-01

Biological synthesis of different metallic and/or oxide nanoparticles and their applications especially in agriculture and biomedical sciences are gaining prominence nowadays due to their handy and reproducible synthetic protocols which are cost-effective and eco-friendly. In this work, green synthesis of zinc oxide nanoparticles (ZnO NPs) using the alcoholic extract of Azadirachta indica as a reducing and stabilizing agent has been presented. Formation of ZnO NPs was confirmed by X-ray diffraction, scanning and transmission electron microscopy techniques. The phytochemicals responsible for nano-transformation were principally alkaloids, flavanoids, terpenoids, tannins and organic acids present in the Azadirachta indica leaves. The synthesized ZnO NPs were used for antimicrobial assays by disc diffusion method against Staphylococcus aureus and Candida albicans. Results showed that ZnO NPs may act as antimicrobial agent especially against skin infections.

Electrochemical Sensing, Photocatalytic and Biological Activities of ZnO Nanoparticles: Synthesis via Green Chemistry Route

Science.gov (United States)

Yadav, L. S. Reddy; Archana, B.; Lingaraju, K.; Kavitha, C.; Suresh, D.; Nagabhushana, H.; Nagaraju, G.

2016-05-01

In this paper, we have successfully synthesized ZnO nanoparticles (Nps) via solution combustion method using sugarcane juice as the novel fuel. The structure and morphology of the synthesized ZnO Nps have been analyzed using various analytical tools. The synthesized ZnO Nps exhibit excellent photocatalytic activity for the degradation of methylene blue dye, indicating that the ZnO Nps are potential photocatalytic semiconductor materials. The synthesized ZnO Nps also show good electrochemical sensing of dopamine. ZnO Nps exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Eschesichia coli and Staphylococcus aureus using agar well diffusion method. Furthermore, the ZnO Nps show good antioxidant activity by potentially scavenging 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The above studies clearly demonstrate versatile applications of ZnO synthesized by simple eco-friendly route.

Biosynthesis and antibacterial activity of ZnO nanoparticles using Trifolium pratense flower extract

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Renata Dobrucka

2016-07-01

Full Text Available Zinc oxide (ZnO has broad applications in various areas. Nanoparticle synthesis using plants is an alternative to conventional physical and chemical methods. It is known that the biological synthesis of nanoparticles is gaining importance due to its simplicity, eco-friendliness and extensive antimicrobial activity. Also, in this study we report the synthesis of ZnO nanoparticles using Trifolium pratense flower extract. The prepared ZnO nanoparticles have been characterized by UV–Vis absorption spectroscopy, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, and scanning electron microscopy (SEM with Energy dispersive X-ray analysis (EDX. Besides, this study determines the antimicrobial efficacy of the synthesized ZnO nanoparticles against clinical and standard strains of S. aureus and P. aeruginosa and standard strain of E. coli.

Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles

Science.gov (United States)

Janaki, A. Chinnammal; Sailatha, E.; Gunasekaran, S.

2015-06-01

The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity.

Facile combustion synthesis of ZnO nanoparticles using Cajanus cajan (L.) and its multidisciplinary applications

Energy Technology Data Exchange (ETDEWEB)

Manjunath, K.; Ravishankar, T.N. [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura Talluk (India); Kumar, Dhanith [Department of Chemistry, B.M.S. Instsitute of Technology, Yelahanka, Bangalore (India); Priyanka, K.P; Varghese, Thomas [Nanoscience Research Centre, Department of Physics, Nirmala College, Muvattupuzha, Kerala (India); Naika, H.Raja [Department of Studies and Research in Environmental Science, Tumkur University, Tumkur (India); Nagabhushana, H. [CNR Rao Center for Advanced Materials, Tumkur University, Tumkur (India); Sharma, S.C. [Chattisgarh Swami Vivekananda Technical University, Bhilai (India); Dupont, J. [Institute of Chemistry, Laboratory of Molecular Catalysis, UFRGS, Porto Alegre (Brazil); Ramakrishnappa, T. [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura Talluk (India); Nagaraju, G., E-mail: nagarajugn@rediffmail.com [Department of Chemistry, B.M.S. Instsitute of Technology, Yelahanka, Bangalore (India)

2014-09-15

Graphical abstract: Facile combustion synthesis of ZnO nanoparticles using Cajanuscajan (L.) and its multidisciplinary applications.Zinc oxide nanoparticles were successfully synthesized by solution combustion method (SCM) using pigeon pea as a combustible fuel for the first time. The as-prepared product shows good photocatalytic, dielectric, antibacterial, electrochemical properties. - Highlights: • ZnO Nps were synthesized via combustion method using pigeon pea as a fuel. • The structure of the product was confirmed by XRD technique. • The morphology was confirmed by SEM and TEM images. • The as-prepared product shown good photocatalytic activity, dielectric property. • It has also shown good antibacterial and electrochemical properties. - Abstract: Zinc oxide nanoparticles (ZnO Nps) were successfully synthesized by solution combustion method (SCM) using pigeon pea as a fuel for the first time. X-Ray diffraction pattern reveals that the product belongs to hexagonal system. FTIR spectrum of ZnO Nps shows the band at 420 cm{sup −1} associated with the characteristic vibration of Zn–O. TEM images show that the nanoparticles are found to be ∼40–80 nm. Furthermore, the as-prepared ZnO Nps exhibits good photocatalytic activity for the photodegradation of methylene blue (MB), indicating that they are indeed a promising photocatalytic semiconductor. The antibacterial properties of ZnO nanopowders were investigated by their bactericidal activity against four bacterial strains.

Facile combustion synthesis of ZnO nanoparticles using Cajanus cajan (L.) and its multidisciplinary applications

International Nuclear Information System (INIS)

Manjunath, K.; Ravishankar, T.N.; Kumar, Dhanith; Priyanka, K.P; Varghese, Thomas; Naika, H.Raja; Nagabhushana, H.; Sharma, S.C.; Dupont, J.; Ramakrishnappa, T.; Nagaraju, G.

2014-01-01

Graphical abstract: Facile combustion synthesis of ZnO nanoparticles using Cajanuscajan (L.) and its multidisciplinary applications.Zinc oxide nanoparticles were successfully synthesized by solution combustion method (SCM) using pigeon pea as a combustible fuel for the first time. The as-prepared product shows good photocatalytic, dielectric, antibacterial, electrochemical properties. - Highlights: • ZnO Nps were synthesized via combustion method using pigeon pea as a fuel. • The structure of the product was confirmed by XRD technique. • The morphology was confirmed by SEM and TEM images. • The as-prepared product shown good photocatalytic activity, dielectric property. • It has also shown good antibacterial and electrochemical properties. - Abstract: Zinc oxide nanoparticles (ZnO Nps) were successfully synthesized by solution combustion method (SCM) using pigeon pea as a fuel for the first time. X-Ray diffraction pattern reveals that the product belongs to hexagonal system. FTIR spectrum of ZnO Nps shows the band at 420 cm −1 associated with the characteristic vibration of Zn–O. TEM images show that the nanoparticles are found to be ∼40–80 nm. Furthermore, the as-prepared ZnO Nps exhibits good photocatalytic activity for the photodegradation of methylene blue (MB), indicating that they are indeed a promising photocatalytic semiconductor. The antibacterial properties of ZnO nanopowders were investigated by their bactericidal activity against four bacterial strains

Effect of capping agents: Structural, optical and biological properties of ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Javed, Rabia [Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Usman, Muhammad, E-mail: uk_phy@yahoo.com [Department of Physics, Faculty of Natural Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Department of Physics, School of Science and Engineering, Lahore University of Management Sciences, Lahore 54729 (Pakistan); Tabassum, Saira; Zia, Muhammad [Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2016-11-15

Highlights: • ZnO nanoparticles have been effectively capped with polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) shown by the data of XRD, FTIR and UV–visible spectroscopy. • Reduction in size occurred from 34 nm to 26 nm due to capping agent and band gap energy increases with the decrease in the particle size. • Antibacterial activity against Gram-positive bacteria is greater than the Gram-negative bacteria. • All biological assays reveal highest activities in capped ZnO nanoparticles as compared to the uncapped ZnO nanoparticles. • Highest antibacterial activity has been exhibited by ZnO-PVP while highest antioxidant and antidiabetic activities have been conferred by ZnO- PEG. - Abstract: Different biological activities of capped and uncapped ZnO nanoparticles were investigated, and the effects of potential capping agents on these biological activities were studied. ZnO nanoparticles were synthesized and capped by polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) using a simple chemical method of co-precipitation. Characterization by X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR) and UV–vis spectroscopy confirmed the crystallinity, size, functional group, and band gap of synthesized nanoparticles. Reduction in size occurred from 34 nm to 26 nm due to surfactant. Results of all biological activities indicated significantly higher values in capped as compared to uncapped nanoparticles. Antibacterial activity against Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC15224), and Acetobacter was obtained. This activity was more prominent against Gram-positive bacteria, and ZnO-PVP nanoparticles elucidated highest antibacterial activity (zone of inhibition 17 mm) against Gram-positive, Bacillus subtilis species. Antioxidant activities including total flavonoid content, total phenolic content, total antioxidant capacity, total reducing power and %age inhibition of DPPH, and

Effect of capping agents: Structural, optical and biological properties of ZnO nanoparticles

International Nuclear Information System (INIS)

Javed, Rabia; Usman, Muhammad; Tabassum, Saira; Zia, Muhammad

2016-01-01

Highlights: • ZnO nanoparticles have been effectively capped with polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) shown by the data of XRD, FTIR and UV–visible spectroscopy. • Reduction in size occurred from 34 nm to 26 nm due to capping agent and band gap energy increases with the decrease in the particle size. • Antibacterial activity against Gram-positive bacteria is greater than the Gram-negative bacteria. • All biological assays reveal highest activities in capped ZnO nanoparticles as compared to the uncapped ZnO nanoparticles. • Highest antibacterial activity has been exhibited by ZnO-PVP while highest antioxidant and antidiabetic activities have been conferred by ZnO- PEG. - Abstract: Different biological activities of capped and uncapped ZnO nanoparticles were investigated, and the effects of potential capping agents on these biological activities were studied. ZnO nanoparticles were synthesized and capped by polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) using a simple chemical method of co-precipitation. Characterization by X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR) and UV–vis spectroscopy confirmed the crystallinity, size, functional group, and band gap of synthesized nanoparticles. Reduction in size occurred from 34 nm to 26 nm due to surfactant. Results of all biological activities indicated significantly higher values in capped as compared to uncapped nanoparticles. Antibacterial activity against Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC15224), and Acetobacter was obtained. This activity was more prominent against Gram-positive bacteria, and ZnO-PVP nanoparticles elucidated highest antibacterial activity (zone of inhibition 17 mm) against Gram-positive, Bacillus subtilis species. Antioxidant activities including total flavonoid content, total phenolic content, total antioxidant capacity, total reducing power and %age inhibition of DPPH, and

Hierarchical nanoflowers assembled with Au nanoparticles decorated ZnO nanosheets toward enhanced photocatalytic properties

DEFF Research Database (Denmark)

Yu, Cuiyan; Yu, Yanlong; Xu, Tao

2017-01-01

Hierarchical nanoflowers assembled with Au nanoparticles (NPs) decorated ZnO nanosheets (Au-ZnO nanosheet flowers, AZNSFs) were successful synthesized. The AZNSFs showed more efficient activity to photodegradation of RhB than that of pure ZnO nanosheet flowers and commercial ZnO nanopowders. The ...

Enhanced antibacterial activity of zinc oxide nanoparticles synthesized using Petroselinum crispum extracts

Energy Technology Data Exchange (ETDEWEB)

Stan, Manuela, E-mail: manuela.stan@itim-cj.ro; Popa, Adriana; Toloman, Dana; Silipas, Teofil-Danut [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania); Vodnar, Dan Cristian [University of Agricultural Sciences and Veterinary Medicine, Department of Food Science and Technology, 3-5 Manastur Street, 400372 Cluj-Napoca (Romania); Katona, Gabriel [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, 400028 Cluj-Napoca (Romania)

2015-12-23

The present contribution reports the synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous leaf and root extracts of Petroselinum crispum (parsley) and characterization of as-prepared samples. ZnO NPs are subjected to X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) studies. The XRD studies reveal a hexagonal wurtzite structure without supplementary diffraction lines for all ZnO samples. TEM analysis shows that the particle size is influenced by the type of plant extract. The EPR spectra indicate the presence of Mn{sup 2+} ions in ZnO sample synthesized using P. crispum leaf extract, while zinc vacancy complexes and oxygen vacancies are evidenced in all analyzed samples. ZnO NPs synthesized using P. crispum extracts exhibit increased (2-16 times) antibacterial activity as compared to chemically synthesized ZnO NPs.

Enhanced antibacterial activity of zinc oxide nanoparticles synthesized using Petroselinum crispum extracts

International Nuclear Information System (INIS)

Stan, Manuela; Popa, Adriana; Toloman, Dana; Silipas, Teofil-Danut; Vodnar, Dan Cristian; Katona, Gabriel

2015-01-01

The present contribution reports the synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous leaf and root extracts of Petroselinum crispum (parsley) and characterization of as-prepared samples. ZnO NPs are subjected to X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) studies. The XRD studies reveal a hexagonal wurtzite structure without supplementary diffraction lines for all ZnO samples. TEM analysis shows that the particle size is influenced by the type of plant extract. The EPR spectra indicate the presence of Mn 2+ ions in ZnO sample synthesized using P. crispum leaf extract, while zinc vacancy complexes and oxygen vacancies are evidenced in all analyzed samples. ZnO NPs synthesized using P. crispum extracts exhibit increased (2-16 times) antibacterial activity as compared to chemically synthesized ZnO NPs

Rapid green synthesis of ZnO nanoparticles using a hydroelectric cell without an electrolyte

Science.gov (United States)

Shah, Jyoti; Kumar Kotnala, Ravinder

2017-09-01

In this study, zinc oxide (ZnO) nanoparticles were synthesized using a novel environmentally friendly hydroelectric cell without an electrolyte or external current source. The hydroelectric cell comprised a nanoporous Li substituted magnesium ferrite pellet in contact with two electrodes, with zinc as the anode and silver as an inert cathode. The surface unsaturated cations and oxygen vacancies in the nanoporous ferrite dissociated water molecules into hydronium and hydroxide ions when the hydroelectric cell was dipped into deionized water. Hydroxide ions migrated toward the zinc electrode to form zinc hydroxide and the hydronium ions were evolved as H2 gas at the silver electrode. The zinc hydroxide collected as anode mud was converted into ZnO nanoparticles by heating at 250 °C. Structural analysis using Raman spectroscopy indicated the good crystallinity of the ZnO nanoparticles according to the presence of a high intensity E2-(high) mode. The nanoparticle size distribution was 5-20 nm according to high resolution transmission electron microscopy. An indirect band gap of 2.75 eV was determined based on the Tauc plot, which indicated the existence of an interstitial cation level in ZnO. Near band edge and blue emissions were detected in photoluminescence spectral studies. The blue emissions obtained from the ZnO nanoparticles could potentially have applications in blue lasers and LEDs. The ZnO nanoparticles synthesized using this method had a high dielectric constant value of 5 at a frequency of 1 MHz, which could be useful for fabricating nano-oscillators. This facile, clean, and cost-effective method obtained a significant yield of 0.017 g for ZnO nanoparticles without applying an external current source.

Facile Synthesis of ZnO Nanoparticles and Their Photocatalytic Activity

Energy Technology Data Exchange (ETDEWEB)

Lee, Jun Young; Ko, Sung Hyun; Kim, Sang Wook [Dongguk Univ., Yongin (Korea, Republic of); Lee, Sookeun; Kim, A Young [Daegu Gyeongbuk Institute of Science and Technology, Daegu (Korea, Republic of)

2014-07-15

This paper reports the facile synthesis methods of zinc oxide (ZnO) nanoparticles, using diethylene glycol (DEG) and polyethylene glycol (PEG400). The particle size and morphology were correlated with the PEG concentration and reaction time. With 0.75 mL of PEG400 in 150 mL of DEG and a 20 h reaction time, the ZnO nanoparticles began to disperse from a collective spherical grain shape. The ZnO nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and a N{sub 2} adsorption.desorption studies. The Brunauer-Emmett-Teller (BET) surface areas of and were 157.083, 141.559 and 233.249 m{sup 2}/g, respectively. The observed pore diameters of and were 63.4, 42.0 and 134.0 A, respectively. The pore volumes of and were 0.249, 0.148 and 0.781 cm{sup 3}/g, respectively. The photocatalytic activity of the synthesized ZnO nanoparticles was evaluated by methylene blue (MB) degradation, and the activity showed a good correlation with the N{sub 2} adsorption.desorption data.

Synthesized zinc peroxide nanoparticles (ZnO2-NPs): a novel antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory approach toward polymicrobial burn wounds.

Science.gov (United States)

Ali, Sameh Samir; Morsy, Reda; El-Zawawy, Nessma Ahmed; Fareed, Mervat F; Bedaiwy, Mohamed Yaser

2017-01-01

Increasing of multidrug resistance (MDR) remains an intractable challenge for burn patients. Innovative nanomaterials are also in high demand for the development of new antimicrobial biomaterials that inevitably have opened new therapeutic horizons in medical approaches and lead to many efforts for synthesizing new metal oxide nanoparticles (NPs) for better control of the MDR associated with the polymicrobial burn wounds. Recently, it seems that metal oxides can truly be considered as highly efficient inorganic agents with antimicrobial properties. In this study, zinc peroxide NPs (ZnO 2 -NPs) were synthesized using the co-precipitation method. Synthesized ZnO 2 -NPs were characterized by X-ray diffraction, Fourier transformed infrared, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and ultraviolet-visible spectroscopy. The characterization techniques revealed synthesis of the pure phase of non-agglomerated ZnO 2 -NPs having sizes in the range of 15-25 nm with a transition temperature of 211°C. Antimicrobial activity of ZnO 2 -NPs was determined against MDR Pseudomonas aeruginosa (PA) and Aspergillus niger (AN) strains isolated from burn wound infections. Both strains, PA6 and AN4, were found to be more susceptible strains to ZnO 2 -NPs. In addition, a significant decrease in elastase and keratinase activities was recorded with increased concentrations of ZnO 2 -NPs until 200 µg/mL. ZnO 2 -NPs revealed a significant anti-inflammatory activity against PA6 and AN4 strains as demonstrated by membrane stabilization, albumin denaturation, and proteinase inhibition. Moreover, the results of in vivo histopathology assessment confirmed the potential role of ZnO 2 -NPs in the improvement of skin wound healing in the experimental animal models. Clearly, the synthesized ZnO 2 -NPs have demonstrated a competitive capability as antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory candidates, suggesting that the

In vitro antibacterial activity of ZnO and Nd doped ZnO nanoparticles against ESBL producing Escherichia coli and Klebsiella pneumoniae

Science.gov (United States)

Hameed, Abdulrahman Syedahamed Haja; Karthikeyan, Chandrasekaran; Ahamed, Abdulazees Parveez; Thajuddin, Nooruddin; Alharbi, Naiyf S.; Alharbi, Sulaiman Ali; Ravi, Ganasan

2016-04-01

Pure ZnO and Neodymium (Nd) doped ZnO nanoparticles (NPs) were synthesized by the co-precipitation method. The synthesized nanoparticles retained the wurtzite hexagonal structure. From FESEM studies, ZnO and Nd doped ZnO NPs showed nanorod and nanoflower like morphology respectively. The FT-IR spectra confirmed the Zn-O stretching bands at 422 and 451 cm-1 for ZnO and Nd doped ZnO NPs respectively. From the UV-VIS spectroscopic measurement, the excitonic peaks were found around 373 nm and 380 nm for the respective samples. The photoluminescence measurements revealed that the broad emission was composed of ten different bands due to zinc vacancies, oxygen vacancies and surface defects. The antibacterial studies performed against extended spectrum β-lactamases (ESBLs) producing strains of Escherichia coli and Klebsiella pneumoniae showed that the Nd doped ZnO NPs possessed a greater antibacterial effect than the pure ZnO NPs. From confocal laser scanning microscopic (CLSM) analysis, the apoptotic nature of the cells was confirmed by the cell shrinkage, disorganization of cell wall and cell membrane and dead cell of the bacteria. SEM analysis revealed the existence of bacterial loss of viability due to an impairment of cell membrane integrity, which was highly consistent with the damage of cell walls.

Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

International Nuclear Information System (INIS)

Diallo, A.; Ngom, B.D.; Park, E.; Maaza, M.

2015-01-01

This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported. - Highlights: • 1st time report on synthesis of ZnO nanoparticles by a green process via Aspalathus linearis extract. • A. linearis's natural extract was used as an effective reduction/oxidizing agent. • Wurtzite nature of ZnO nanoparticles was confirmed via XRD, Raman, XPS and PL

Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

Energy Technology Data Exchange (ETDEWEB)

Diallo, A.; Ngom, B.D. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Park, E. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Nelson Mandela African Institute for Science & Technology, Arusha (Tanzania, United Republic of); Maaza, M., E-mail: Maaza@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa)

2015-10-15

This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported. - Highlights: • 1st time report on synthesis of ZnO nanoparticles by a green process via Aspalathus linearis extract. • A. linearis's natural extract was used as an effective reduction/oxidizing agent. • Wurtzite nature of ZnO nanoparticles was confirmed via XRD, Raman, XPS and PL.

Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers

International Nuclear Information System (INIS)

Dybowska, Agnieszka D.; Croteau, Marie-Noele; Misra, Superb K.; Berhanu, Deborah; Luoma, Samuel N.; Christian, Paul; O'Brien, Paul; Valsami-Jones, Eugenia

2011-01-01

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn ( 67 Zn) ZnO nanoparticles and measured the uptake of 67 Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range ( -1 ). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 μg g -1 which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions. - ZnO nanoparticles with distinct isotopic composition can be tailor synthesized to be used as tracers of environmental fate and uptake by organisms.

Trioctylphosphine-assisted morphology control of ZnO nanoparticles

Science.gov (United States)

Hong, Yun-Kun; Cho, GeonHee; Park, YoonSu; Oh, Soong Ju; Ha, Don-Hyung

2018-06-01

This study investigates the morphological change in colloidal ZnO nanoparticles (NPs) synthesized with trioctylphosphine (TOP). The addition of TOP to the synthesis causes an evolution in the shape of ZnO NPs to tadpole-like particles from quasi-spherical particles at 300 °C. The total length of the tadpole-like ZnO NPs can be modified by controlling the molar ratio of TOP to oleylamine (OLAM). The tadpole-like particles are elongated as the concentration of TOP increased but decreased when the addition of TOP is excessive. These tadpole-like ZnO NPs transform to quasi-spherical NPs regardless of the amount of TOP at a reaction time of 3 h at 300 °C. At 200 °C, the effect of TOP on the ZnO NP synthesis differs from that at 300 °C. The ZnO NPs synthesized by controlling the molar ratios of surfactant ligands (TOP:OLAM = 2:100 and 70:100) at 200 °C share similar amorphous structures, while a crystalline ZnO phase is formed when the reaction time is 3 h. X-ray photoelectron spectroscopy analysis shows that TOP influences the oxidation of ZnO and suggests that a combination of OLAM and TOP plays a role in controlling the shape of ZnO NPs. These results provide critical insights to the utilization of TOP for a shape controlling ligand in ZnO NPs and suggest a new route to design oxide NPs.

Synthesis and physicochemical characterizations and antimicrobial activity of ZnO nanoparticles

Science.gov (United States)

Sharma, Bhumika K.; Patel, Kinjal; Roy, Debesh R.

2018-05-01

Nanoparticles exhibit very interesting and useful physicochemical properties when they interact with substrates and goes through some physicochemical and/or biological processes. ZnO is known to be a highly demanding nanomaterial due to its discreet properties, shapes and sizes. A detail experimental study on the synthesis, characterization and antibacterial activity of ZnO nanoparticles (NPs) is performed. ZnO NPs are synthesized using chemical precipitation method. The understanding of crystal structure, morphology and elemental compositions are explained using Powder X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FE-SEM) respectively. Fourier transform infrared spectroscopy (FTIR) is performed to achieve the information on the presence of various functional groups. The antibacterial activity of these ZnO NPs is investigated in terms of Zone of Inhibition (ZOI) against Escherichia coli (Gram negative) microorganisms.

Magnetic and optical properties of manganese doped ZnO nanoparticles synthesized by sol-gel technique

KAUST Repository

Omri, Karim; El Ghoul, Jaber; Lemine, O. M.; Bououdina, M.; Zhang, Bei; El Mir, Lassaad

2013-01-01

Mn doped ZnO nanoparticles with different doping concentration (1, 2, 3, 4, 5 at.%) were prepared by sol-gel method using supercritical drying conditions of ethyl alcohol. The structural, morphological, optical and magnetic properties of the as-prepared nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV measurements and superconducting quantum interference device (SQUID). The structural properties showed that the undoped and Mn doped ZnO nanoparticles exhibit hexagonal wurtzite structure. From the optical studies, the transmittance in UV region was decreased with the increase of Mn concentration. For Mn doped ZnO nanoparticles the optical band gap varies between 3.34 eV and 3.22 eV. It was found that the doping Mn 2+ ions have a significant influence on the optical properties. The magnetic characterization of the samples with 1% and 5% Mn concentrations reveal diamagnetic behavior for the first one and the presence of both paramagnetic and ferromagnetic behavior for the second. The room ferromagnetic component is due to the presence of the secondary phase ZnOMn3 which is confirmed by XRD study. © 2013 Elsevier Ltd. All rights reserved.

Magnetic and optical properties of manganese doped ZnO nanoparticles synthesized by sol-gel technique

KAUST Repository

Omri, Karim

2013-08-01

Mn doped ZnO nanoparticles with different doping concentration (1, 2, 3, 4, 5 at.%) were prepared by sol-gel method using supercritical drying conditions of ethyl alcohol. The structural, morphological, optical and magnetic properties of the as-prepared nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV measurements and superconducting quantum interference device (SQUID). The structural properties showed that the undoped and Mn doped ZnO nanoparticles exhibit hexagonal wurtzite structure. From the optical studies, the transmittance in UV region was decreased with the increase of Mn concentration. For Mn doped ZnO nanoparticles the optical band gap varies between 3.34 eV and 3.22 eV. It was found that the doping Mn 2+ ions have a significant influence on the optical properties. The magnetic characterization of the samples with 1% and 5% Mn concentrations reveal diamagnetic behavior for the first one and the presence of both paramagnetic and ferromagnetic behavior for the second. The room ferromagnetic component is due to the presence of the secondary phase ZnOMn3 which is confirmed by XRD study. © 2013 Elsevier Ltd. All rights reserved.

Investigation of some physical properties of ZnO nanofilms synthesized by micro-droplet technique

Directory of Open Access Journals (Sweden)

N. Hamzaoui

Full Text Available In this paper, ZnO nanocrystals were synthesized using a simple micro-droplets technique from a solution prepared by dissolving zinc acetate di-hydrate [Zn(CH3COO2, 2H2O] in methanol. Microdroplets were deposited on glass substrates heated at 100 °C, the obtained samples of ZnO films were investigated by XRD, AES, AFM, ellipsometry and PL. XRD patterns reveal the wurtzite structure of ZnO where the lattice parameters a and c, calculated from XRD signals, show a nanometric character of ZnO nanoparticles. The chemical composition of ZnO film surfaces was verified by Auger electron spectroscopy (AES. From Auger signals, oxygen (O-KLL and zinc (Zn-LMM Auger transitions indicate well the presence of Zn-O bonding. The surface topography of the samples was measured by atomic force microscopy (AFM where ZnO nanoparticles of average size ranging between 20 and 80 nm were determined. Some optical properties as dielectric constants, refractive index, extinction coefficient as well as the optical band gap were determined from ellipsometry analysis. The dispersion of the refractive index was discussed in terms of both Cauchy parameters and Wemple & Di-Dominico single oscillator model. The photoluminescence (PL measurements exhibited two emission peaks. The first at 338 nm, corresponding to the band gap of ZnO, is due to excitonic emission while the second around 400 nm, is attributed to the single ionized oxygen vacancies. Keywords: ZnO nanoparticles, Micro droplets technique, AFM, Auger spectroscopy, Ellipsometry, Photoluminescence (PL

Photoluminescent ZnO Nanoparticles and Their Biological Applications

Directory of Open Access Journals (Sweden)

Zheng-Yong Zhang

2015-05-01

Full Text Available During the past decades, numerous achievements concerning luminescent zinc oxide nanoparticles (ZnO NPs have been reported due to their improved luminescence and good biocompatibility. The photoluminescence of ZnO NPs usually contains two parts, the exciton-related ultraviolet (UV emission and the defect-related visible emission. With respect to the visible emission, many routes have been developed to synthesize and functionalize ZnO NPs for the applications in detecting metal ions and biomolecules, biological fluorescence imaging, nonlinear multiphoton imaging, and fluorescence lifetime imaging. As the biological applications of ZnO NPs develop rapidly, the toxicity of ZnO NPs has attracted more and more attention because ZnO can produce the reactive oxygen species (ROS and release Zn2+ ions. Just as a coin has two sides, both the drug delivery and the antibacterial effects of ZnO NPs become attractive at the same time. Hence, in this review, we will focus on the progress in the synthetic methods, luminescent properties, and biological applications of ZnO NPs.

Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers

Energy Technology Data Exchange (ETDEWEB)

Dybowska, Agnieszka D., E-mail: a.dybowska@nhm.ac.u [Department of Mineralogy, Natural History Museum London, Cromwell Road, London, SW7 5BD (United Kingdom); Croteau, Marie-Noele [U.S. Geological Survey, 345 Middlefield Road, MS 496, Menlo Park, CA 94025 (United States); Misra, Superb K.; Berhanu, Deborah [Department of Mineralogy, Natural History Museum London, Cromwell Road, London, SW7 5BD (United Kingdom); Luoma, Samuel N. [Department of Mineralogy, Natural History Museum London, Cromwell Road, London, SW7 5BD (United Kingdom); U.S. Geological Survey, 345 Middlefield Road, MS 496, Menlo Park, CA 94025 (United States); Christian, Paul; O' Brien, Paul [School of Chemistry, University of Manchester, M13 9PL, Manchester (United Kingdom); Valsami-Jones, Eugenia [Department of Mineralogy, Natural History Museum London, Cromwell Road, London, SW7 5BD (United Kingdom)

2011-01-15

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn ({sup 67}Zn) ZnO nanoparticles and measured the uptake of {sup 67}Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 {mu}g g{sup -1}). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 {mu}g g{sup -1} which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions. - ZnO nanoparticles with distinct isotopic composition can be tailor synthesized to be used as tracers of environmental fate and uptake by organisms.

Electrochemical investigation of the properties of Co doped ZnO nanoparticle as a corrosion inhibitive pigment for modifying corrosion resistance of the epoxy coating

International Nuclear Information System (INIS)

Rostami, M.; Rasouli, S.; Ramezanzadeh, B.; Askari, A.

2014-01-01

Highlights: • Corrosion inhibitive pigment based on ZnOCo was synthesized through combustion method. • Doping ZnO nanoparticle with Co enhanced its inhibition properties considerably. • ZnOCo nanoparticle could enhance corrosion protective performance of epoxy coating. • Co doped ZnO nanoparticles behaved as efficient barrier and inhibitive pigment. - Abstract: Co doped ZnO nanoparticles were synthesized by combustion method. Then, the epoxy nanocomposites were prepared using various amounts of nanoparticles. Salt spray and electrochemical impedance spectroscopy (EIS) were used in order to investigate the corrosion inhibition effects of nanoparticles on the steel substrate. The morphology and composition of the films precipitated on the steel surface were investigated by scanning electron microscope (SEM) and energy dispersive spectroscopy. Results revealed that the corrosion inhibition properties of ZnO nanoparticle were significantly enhanced after doping with Co. Moreover, Co doped ZnO nanoparticles enhanced the corrosion resistance of the epoxy coating effectively

A review on bio-synthesized zinc oxide nanoparticles using plant extracts as reductants and stabilizing agents.

Science.gov (United States)

Basnet, Parita; Inakhunbi Chanu, T; Samanta, Dhrubajyoti; Chatterjee, Somenath

2018-06-01

In the age of technology, nanoparticles have proven to be one of the essential needs for development. These nanoparticles have the potential to be used for a wide variety of applications, thereby, development in improving the quality of nanoparticles, to make them more application specific, is still under research. In this regard, an important point to note is that the procedures employed in synthesizing nanoparticles require to be cost-effective and less-steps involved and have an additional advantage, i.e. they should be eco-friendly. This means that the synthesis procedure needs avoiding the use of harmful chemicals, and negligible generation of any noxious by-products. The green synthesis (biosynthesis) method employs simple procedures, easily available raw materials and ambiance for the synthesis process, where the precursors used are safe, with minute possibility for the production of harmful by-products. Considering these advantages, the current review includes a brief description on the various chemical and physical synthesis method of zinc oxide (ZnO) nanoparticles with emphasis on the biosynthesis of ZnO nanoparticles using plant extracts (and briefly microbes), the phytochemicals present in the plant extracts, the plausible mechanisms involved in the formation of ZnO nanoparticles and applications of the as-synthesized ZnO nanoparticles as photocatalysts and microbial inhibitors. Copyright © 2018 Elsevier B.V. All rights reserved.

Positron annihilation spectroscopic studies of solvothermally synthesized ZnO nanobipyramids and nanoparticles

Science.gov (United States)

Ghoshal, Tandra; Biswas, Subhajit; Kar, Soumitra; Chaudhuri, Subhadra; Nambissan, P. M. G.

2008-02-01

Zinc oxide (ZnO) samples in the form of hexagonal-based bipyramids and particles of nanometer dimensions were synthesized through solvothermal route and characterized by x-ray diffraction and transmission electron microscopy. Positron annihilation experiments were performed to study the structural defects such as vacancies and surfaces in these nanosystems. From coincidence Doppler broadening measurements, the positron trapping sites were identified as Zn vacancies or Zn-O-Zn trivacancy clusters. The positron lifetimes, their relative intensities, and the Doppler broadened lineshape parameter S all showed characteristic changes across the nanobipyramid size corresponding to the thermal diffusion length of positrons. In large nanobipyramids, vacancies within the crystallites also trapped positrons and the effects of agglomeration of such vacancies due to increased temperatures of synthesis were reflected in the variation of the annihilation parameters with their base diameters. The sizes of the nanoparticles used were all in the limit of thermal diffusion length of positrons and the annihilation characteristics were in accordance with the decreasing contribution from surfaces with increasing particle size.

Effect of iron doping concentration on magnetic properties of ZnO nanoparticles

International Nuclear Information System (INIS)

Sharma, Prashant K.; Dutta, Ranu K.; Pandey, Avinash C.; Layek, Samar; Verma, H.C.

2009-01-01

The ZnO:Fe nanoparticles of mean size 3-10 nm were synthesized at room temperature by simple co-precipitation method. The crystallite structure, morphology and size estimation were performed by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM). The wurtzite structure of ZnO gradually degrades with the increasing Fe doping concentration. The magnetic behavior of the nanoparticles of ZnO with varying Fe doping concentration was investigated using a vibrating sample magnetometer (VSM). Initially these nanoparticles showed strong ferromagnetic behavior, however at higher doping percentage of Fe, the ferromagnetic behavior was suppressed and paramagnetic nature was observed. The enhanced antiferromagnetic interaction between neighboring Fe-Fe ions suppressed the ferromagnetism at higher doping concentrations of Fe. Room-temperature Moessbauer spectroscopy investigation showed Fe 3+ nature of the iron atom in ZnO matrix.

Antibacterial effect of novel synthesized sulfated β-cyclodextrin crosslinked cotton fabric and its improved antibacterial activities with ZnO, TiO2 and Ag nanoparticles coating.

Science.gov (United States)

Selvam, S; Rajiv Gandhi, R; Suresh, J; Gowri, S; Ravikumar, S; Sundrarajan, M

2012-09-15

Sulfated β-cyclodextrin was synthesized from sulfonation of β-cyclodextrin and sulfated polymer was crosslinked with cotton fabric using ethylenediaminetetraacetic acid as crosslinker. ZnO, TiO(2) and Ag nanoparticles were prepared and characterized by XRD, UV, DLS, SEM and PSA. The prepared nanoparticles were coated on crosslinked cotton fabric. The crosslinking and nanoparticles coating effects of cotton fabrics were studied by FTIR and SEM analysis. The antibacterial test was done against gram positive Staphylococcus aureus and gram negative Escherichia coli bacterium. Copyright © 2012 Elsevier B.V. All rights reserved.

Visible light photocatalytic activities of ZnFe_2O_4/ZnO nanoparticles for the degradation of organic pollutants

International Nuclear Information System (INIS)

Rameshbabu, R.; Kumar, Niraj; Karthigeyan, A.; Neppolian, B.

2016-01-01

ZnFe_2O_4/ZnO nanoparticles have been synthesized by co-precipitation method using polyvinyl alcohol (PVA) as surfactant. The phase formation of synthesized products was systematically investigated from powder X-ray diffraction. Cubic ZnFe_2O_4 and hexagonal ZnO were identified in accordance with different molar concentrations of Fe"3"+ ions. The morphology and functionality were analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The optical properties and change in the band gap from UV to visible region upon increasing molar concentration of Fe"3"+ ions were analyzed from diffuse reflectance spectra (DRS). Superparamagnetic property was observed for synthesized ZnFe_2O_4/ZnO nanoparticles using vibrating sample magnetometer (VSM). The methylene blue and methyl orange were taken as model dyes to illustrate the photocatalytic activity of synthesized products under visible light irradiation. Maximum degradation of 99% for methyl orange (MO) was achieved by the use of 13 nm sized ZnFe_2O_4/ZnO nanoparticles as catalyst and a minutely less activity was observed for the methylene blue (MB) degradation (98%), when the photocatalytic processes were carried out for 5 h and 6 h, respectively. - Highlights: • Co-precipitation method is proposed to synthesize magnetic nanoparticles. • Modifications in the molar concentration lead to the shift in absorption edge. • Superparamagnetic property is demonstrated for the nanoparticles. • Two dye pollutants are utilized to demonstrate the photocatalytic activity.

Microwave assisted biosynthesis of rice shaped ZnO nanoparticles using Amorphophallus konjac tuber extract and its application in dye sensitized solar cells

Directory of Open Access Journals (Sweden)

Naresh Kumar P.

2017-02-01

Full Text Available Rice shaped ZnO nanoparticles have been synthesized for the first time by a biological process using Amorphophallus konjac tuber extract and used as a photoanode in a dye sensitized solar cell. The glucomannan present in aqueous tuber extract acted as a reducing agent in the synthesis process, further it also acted as a template which modified and controlled the shape of the nanoparticles. The synthesized nanoparticles were dried by microwave irradiation followed by annealing at 400 °C. The FESEM and TEM images confirmed that the synthesized ZnO nanoparticles had rice shaped morphology. Furthermore, the X-ray diffraction studies revealed that the prepared ZnO nanoparticles exhibited wurtzite phase with average particle size of 17.9 nm. The UV-Vis spectroscopy studies confirmed the value of band gap energy of biosynthesized ZnO nanoparticles as 3.11 eV. The photoelectrodes for dye sensitized solar cells were prepared with the biosynthesized ZnO nanoparticles using doctor blade method. The photoelectrode was sensitized using the fruit extract of Terminalia catappa, flower extracts of Callistemon citrinus and leaf extracts of Euphorbia pulcherrima. The dye sensitized solar cells were fabricated using the sensitized photoelectrode and their open circuit voltages and short circuit current densities were found to be in the range of 0.45 V to 0.55 V and 5.6 mA/cm2 to 6.8 mA/cm2, respectively. Thus, the photovoltaic performances of all the natural dye sensitized ZnO solar cells show better conversion efficiencies due to the morphology and preparation technique.

Photocatalytic degradation of the Paracetamol drug using Lanthanum doped ZnO nanoparticles and their in-vitro cytotoxicity assay

International Nuclear Information System (INIS)

Shakir, Mohammad; Faraz, Mohd; Sherwani, Mohd Asif; Al-Resayes, Saud I.

2016-01-01

The doping of semiconductor by rare earth metals nanoparticles is an effective way for increasing photocatalytic activity. Zinc oxide and Lanthanum doped Zinc oxide nanoparticles were synthesized by modifying the gel-combustion method. It was found that La can greatly enhance the cytotoxicity and photocatalytic activity of ZnO nanoparticles towards various cell lines and Paracetamol drug. These nanoparticles were characterized by various spectroscopic and other techniques which clearly revealed the presence of lanthanum ions. The absorption edge shifts towards the visible region after doping with La ions. This shift shows that the doping of La ions is favorable for absorbing the visible light. The comparative photocatalytic and cytotoxicity activity revealed that La doped ZnO nanoparticles remarkably enhanced activities as compared to the ZnO nanoparticles. The outcome of these studies offers valuable for planning La doped ZnO nanoparticles having cytotoxicity and photocatalytic activities helpful for the formulation of anticancer product and waste water remediation.

Photocatalytic degradation of the Paracetamol drug using Lanthanum doped ZnO nanoparticles and their in-vitro cytotoxicity assay

Energy Technology Data Exchange (ETDEWEB)

Shakir, Mohammad, E-mail: shakir078@yahoo.com [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Faraz, Mohd [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Sherwani, Mohd Asif [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002 (India); Al-Resayes, Saud I. [Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)

2016-08-15

The doping of semiconductor by rare earth metals nanoparticles is an effective way for increasing photocatalytic activity. Zinc oxide and Lanthanum doped Zinc oxide nanoparticles were synthesized by modifying the gel-combustion method. It was found that La can greatly enhance the cytotoxicity and photocatalytic activity of ZnO nanoparticles towards various cell lines and Paracetamol drug. These nanoparticles were characterized by various spectroscopic and other techniques which clearly revealed the presence of lanthanum ions. The absorption edge shifts towards the visible region after doping with La ions. This shift shows that the doping of La ions is favorable for absorbing the visible light. The comparative photocatalytic and cytotoxicity activity revealed that La doped ZnO nanoparticles remarkably enhanced activities as compared to the ZnO nanoparticles. The outcome of these studies offers valuable for planning La doped ZnO nanoparticles having cytotoxicity and photocatalytic activities helpful for the formulation of anticancer product and waste water remediation.

Magnetically separable core–shell ZnFe_2O_4@ZnO nanoparticles for visible light photodegradation of methyl orange

International Nuclear Information System (INIS)

Kulkarni, Suresh D.; Kumbar, Sagar; Menon, Samvit G.; Choudhari, K.S.; Santhosh, C.

2016-01-01

Highlights: • Phase pure, magnetic ZnFe_2O_4@ZnO nanoparticles synthesized with excellent yield. • ZnFe_2O_4@ZnO displayed higher UV photocatalytic efficiency than ZnO nanoparticles. • First report on visible light photodegradation of methyl orange by ZnFe_2O_4@ZnO. • Excellent reusability of ZnFe_2O_4@ZnO nanoparticles observed for azo dye removal. - Abstract: Visible light photodegradation of aqueous methyl orange using magnetically separable core–shell ZnFe_2O_4@ZnO nanoparticles is reported. A combination of low temperature (190 °C) microwave synthesis and hydrothermal method were used to prepare phase pure material with excellent yield (95%). The magnetic separability, surface area of 41 m"2/g and visible light absorption make ZnFe_2O_4@ZnO nanoparticles a good solar photocatalyst. ZnFe_2O_4@ZnO displayed greater UV photocatalytic efficiency than ZnO owing to the generation of large number of electron-hole pairs. Visible light photodegradation of MO using ZnFe_2O_4@ZnO nanoparticles is reported for the first time. Higher first order rate constants under both UV and visible light for core-shell nanoparticles suggested their superiority over its individual oxides. The ZnFe_2O_4@ZnO showed excellent reusability with high photocatalytic efficiencies suggesting its suitability for solar photocatalytic applications.

Structural, optical, photoluminescence and photocatalytic assessment of Sr-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Pradeev Raj, K.; Sadaiyandi, K.; Kennedy, A.; Thamizselvi, R.

2016-01-01

ZnO nanoparticles (NPs) and Strontium doped ZnO nanoparticles (2–6 mol %) (SZ-NPs) were synthesized via Co-precipitation method. Synthesized samples were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Elemental dispersive spectroscopy (EDS), UV–visible, and Photoluminescence (PL) spectroscopy. Photocatalytic studies for Rhodamine B (RhB) dye in aqueous solution under UV–Vis radiation. XRD analysis confirms that all the samples have hexagonal wurtzite structure. The average crystallite size of the nanoparticles was in the range of 29–51 nm. From the Williamson –Hall (W-H) plot, a positive slope is inferred for pure and SZ-NPs, confirming the presence of tensile strain. SEM images reveal the synthesized NPs are in nanometer range with various shapes are observed. The presence of strontium (Sr) in the host lattice was confirmed by EDS spectroscopy. The optical analysis shows the absorption decreases on doping and shifts slightly towards the longer wavelength region. The band gap energy (Eg) decreases (3.32–3.03 eV) with the increase of Sr dopant concentration. The photoluminescence (PL) spectrum reveals the UV emission is strong near the band-edge region (NBE) (392 nm) and intrinsic defects resulted in series of Vis emissions around 400–560 nm. Kinetic studies on RhB dye indicates the degradation rate has increased with dopant concentration. The improved photocatalytic activity is observed due to the efficient charge separation, improved visible light absorption, inhibition of the electron-hole pair's recombination and better adsorptive of RhB dye molecule on the surface of SZ-NPs. Moreover, the reduction in the total organic carbon (TOC) results reveals the improved photocatalytic activity of strontium doped ZnO NPs. - Highlights: • Effective synthesis of ZnO and Sr−ZnO nanoparticles by co-precipitation method. • Samples were characterized by XRD, SEM, EDS, UV–Vis and PL technique. • Higher optical absorption and

Structural, optical, photoluminescence and photocatalytic assessment of Sr-doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pradeev Raj, K., E-mail: pradeevraj@gmail.com [Research and Development Centre, Bharathiar University, Coimbatore, 641 046, Tamilnadu (India); Department of Physics, CSI College of Engineering, Ooty, The Nilgiris, 643 215, Tamil Nadu (India); Sadaiyandi, K. [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivagangai, 630 003, Tamil Nadu (India); Kennedy, A. [Department of Physics, CSI College of Engineering, Ooty, The Nilgiris, 643 215, Tamil Nadu (India); Thamizselvi, R. [Department of Chemistry, L.R.G. Govt Arts College for Women, Tirupur, 641604, Tamil Nadu (India)

2016-11-01

ZnO nanoparticles (NPs) and Strontium doped ZnO nanoparticles (2–6 mol %) (SZ-NPs) were synthesized via Co-precipitation method. Synthesized samples were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Elemental dispersive spectroscopy (EDS), UV–visible, and Photoluminescence (PL) spectroscopy. Photocatalytic studies for Rhodamine B (RhB) dye in aqueous solution under UV–Vis radiation. XRD analysis confirms that all the samples have hexagonal wurtzite structure. The average crystallite size of the nanoparticles was in the range of 29–51 nm. From the Williamson –Hall (W-H) plot, a positive slope is inferred for pure and SZ-NPs, confirming the presence of tensile strain. SEM images reveal the synthesized NPs are in nanometer range with various shapes are observed. The presence of strontium (Sr) in the host lattice was confirmed by EDS spectroscopy. The optical analysis shows the absorption decreases on doping and shifts slightly towards the longer wavelength region. The band gap energy (Eg) decreases (3.32–3.03 eV) with the increase of Sr dopant concentration. The photoluminescence (PL) spectrum reveals the UV emission is strong near the band-edge region (NBE) (392 nm) and intrinsic defects resulted in series of Vis emissions around 400–560 nm. Kinetic studies on RhB dye indicates the degradation rate has increased with dopant concentration. The improved photocatalytic activity is observed due to the efficient charge separation, improved visible light absorption, inhibition of the electron-hole pair's recombination and better adsorptive of RhB dye molecule on the surface of SZ-NPs. Moreover, the reduction in the total organic carbon (TOC) results reveals the improved photocatalytic activity of strontium doped ZnO NPs. - Highlights: • Effective synthesis of ZnO and Sr−ZnO nanoparticles by co-precipitation method. • Samples were characterized by XRD, SEM, EDS, UV–Vis and PL technique. • Higher optical absorption

Visible light photocatalytic activities of ZnFe{sub 2}O{sub 4}/ZnO nanoparticles for the degradation of organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Rameshbabu, R. [SRM Research Institute, SRM University, Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Kumar, Niraj [SRM Research Institute, SRM University, Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Centre for Materials Science and Nano Devices, Department of Physics and Nanotechnology, SRM University Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Karthigeyan, A., E-mail: karthigeyan.a@ktr.srmuniv.ac.in [Centre for Materials Science and Nano Devices, Department of Physics and Nanotechnology, SRM University Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Neppolian, B., E-mail: neppolian.b@res.srmuniv.ac.in [SRM Research Institute, SRM University, Kattankulathur, Kanchipuram 603203, Tamil Nadu (India)

2016-09-15

ZnFe{sub 2}O{sub 4}/ZnO nanoparticles have been synthesized by co-precipitation method using polyvinyl alcohol (PVA) as surfactant. The phase formation of synthesized products was systematically investigated from powder X-ray diffraction. Cubic ZnFe{sub 2}O{sub 4} and hexagonal ZnO were identified in accordance with different molar concentrations of Fe{sup 3+} ions. The morphology and functionality were analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The optical properties and change in the band gap from UV to visible region upon increasing molar concentration of Fe{sup 3+} ions were analyzed from diffuse reflectance spectra (DRS). Superparamagnetic property was observed for synthesized ZnFe{sub 2}O{sub 4}/ZnO nanoparticles using vibrating sample magnetometer (VSM). The methylene blue and methyl orange were taken as model dyes to illustrate the photocatalytic activity of synthesized products under visible light irradiation. Maximum degradation of 99% for methyl orange (MO) was achieved by the use of 13 nm sized ZnFe{sub 2}O{sub 4}/ZnO nanoparticles as catalyst and a minutely less activity was observed for the methylene blue (MB) degradation (98%), when the photocatalytic processes were carried out for 5 h and 6 h, respectively. - Highlights: • Co-precipitation method is proposed to synthesize magnetic nanoparticles. • Modifications in the molar concentration lead to the shift in absorption edge. • Superparamagnetic property is demonstrated for the nanoparticles. • Two dye pollutants are utilized to demonstrate the photocatalytic activity.

Effect of calcination temperature on the structural, optical and magnetic properties of pure and Fe-doped ZnO nanoparticles

Directory of Open Access Journals (Sweden)

Pal Singh Raminder Preet

2016-06-01

Full Text Available In the present study, pure ZnO and Fe-doped ZnO (Zn0.97Fe0.03O nanoparticles were synthesized by simple coprecipitation method with zinc acetate, ferric nitrate and sodium hydroxide precursors. Pure ZnO and Fe-doped ZnO were further calcined at 450 °C, 600 °C and 750 °C for 2 h. The structural, morphological and optical properties of the samples were characterized by X-ray diffractometer (XRD, scanning electron microscope (SEM, energy dispersive spectroscopy (EDS and UV-Vis absorption spectroscopy. The X-ray diffraction studies revealed that the as-synthesized pure and doped ZnO nanoparticles have hexagonal wurtzite structure. The average crystallite size was calculated using Debye-Scherrer’s formula. The particle size was found to be in nano range and increased with an increase in calcination temperature. SEM micrographs confirmed the formation of spherical nanoparticles. Elemental compositions of various elements in pure and doped ZnO nanoparticles were determined by EDX spectroscopy. UV-Vis absorption spectra showed red shift (decrease in band gap with increasing calcination temperature. Effect of calcination on the magnetic properties of Fe-doped ZnO sample was also studied using vibrating sample magnetometer (VSM. M-H curves at room temperature revealed that coercivity and remanent polarization increase with an increase in calcination temperature from 450 °C to 750 °C, whereas reverse effect was observed for magnetization saturation.

Organometallic synthesis of ZnO nanoparticles for gas sensing: towards selectivity through nanoparticles morphology

Energy Technology Data Exchange (ETDEWEB)

Ryzhikov, Andrey; Jońca, Justyna; Kahn, Myrtil; Fajerwerg, Katia [Laboratoire de Chimie de Coordination (LCC), CNRS (France); Chaudret, Bruno [Laboratoire de Physique et de Chimie de Nano-objets (LPCNO), INSA, UPS, CNRS (France); Chapelle, Audrey [Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS), CNRS (France); Ménini, Philippe [Université Toulouse III, Paul Sabatier (France); Shim, Chang Hyun [Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS), CNRS (France); Gaudon, Alain [Alpha M.O.S. SA (France); Fau, Pierre, E-mail: pierre.fau@lcc-toulouse.fr [Laboratoire de Chimie de Coordination (LCC), CNRS (France)

2015-07-15

ZnO nanoparticles (NP) with different morphologies such as nanorods (NR), isotropic NP, and cloud-like (CL) structures have been synthesized by an organometallic route. The prepared ZnO nanostructures have been deposited on miniaturized silicon gas sensor substrates by an inkjet method, and their responses to CO, C{sub 3}H{sub 8}, and NH{sub 3} gases have been studied at different operating temperatures (340–500 °C) and relative humidity of 50 %. It is noteworthy that the morphology of the nanostructure of the sensitive layer is maintained after thermal treatment. The morphology of ZnO NP significantly influences the sensor response level and their selectivity properties to reducing gases. Among the three different ZnO types, sensors prepared with NR show the highest response to both CO and C{sub 3}H{sub 8}. Sensors made of isotropic NP and CL structures show a lower but similar response to CO. From all investigated nanostructures, sensors made of CL structures show the weakest response to C{sub 3}H{sub 8}. With NH{sub 3} gas, no effect of the morphology of the ZnO sensitive layer has been evidenced. These different responses highlight the important role of the nanostructure of the ZnO sensitive layer and the nature of the target gas on the detection properties of the sensors. Graphical Abstract: Three different ZnO nanoparticles morphologies (cloud-like, dots, rods) have been employed as sensitive layers in chemoresistive sensors for the selective detection of CO, C{sub 3}H{sub 8} and NH{sub 3}.

Synthesis, characterization and photocatalysis enhancement of Eu2O3-ZnO mixed oxide nanoparticles

Science.gov (United States)

Mohamed, W. S.; Abu-Dief, Ahmed M.

2018-05-01

Pure ZnO nanoparticles (NPs) and mixed Eu2O3 and ZnO NPs with different Eu2O3 ratios (5%, 10%, and 15%) were synthesized by a precipitation method under optimum conditions. The synthesized samples were characterized by means of X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and UV-vis diffuse reflectance spectroscopy. The as-synthesized ZnO NPs exhibit high phase purity and a highly crystalline wurtzite ZnO structure. The mixed Eu2O3 and ZnO NPs exhibit a Eu2O3 zinc blend phase in addition to the wurtzite phase of pure ZnO, confirming the high purity and good crystallinity of the as-synthesized samples. The high-purity formation of ZnO and Eu2O3 phases was confirmed by FTIR and Raman spectra. Microstructural analysis by SEM and TEM confirmed the sphere-like morphology with different particle sizes (29-40 nm) of the as-synthesized samples. The photocatalytic activities of pure ZnO NPs and mixed Eu2O3 and ZnO NPs for the degradation of methylene blue were evaluated under ultraviolet (UV) irradiation. The results show that Eu2O3 plays an important role in the enhancement of the photocatalytic properties of ZnO NPs. We found that mixed 5% Eu2O3 and ZnO NPs exhibit the highest photocatalytic activity (degradation efficiency of 96.5% after 180 min of UV irradiation) as compared with pure ZnO NPs (degradation efficiency of 80.3% after 180 min of UV irradiation). The increased photocatalytic activity of the optimum mixed Eu2O3 and ZnO NPs is due to the high crystallinity, high surface area with small particle size, and narrow energy gap.

Photocatalytic degradation of some organic dyes under solar light irradiation using TiO2 and ZnO nanoparticles

Directory of Open Access Journals (Sweden)

Mojtaba Amini

2016-01-01

Full Text Available Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB, Methylene blue (MB and Acridine orange (AO under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.

Facile biosynthesis, characterization, and solar assisted photocatalytic effect of ZnO nanoparticles mediated by leaves of L. speciosa.

Science.gov (United States)

Sai Saraswathi, V; Tatsugi, J; Shin, Paik-Kyun; Santhakumar, K

2017-02-01

Synthesis of metal oxide nanoparticles using novel methodologies always attracts great importance in research. The use of plant extract to synthesize nano-particle has been considered as one of the eco-friendly methods. This paper describes the biosynthetic route of preparation of zinc oxide nanoparticles (ZnO NPs) from the Lagerstroemia speciosa leaf extract. This approach appears to be low-cost preparation and alternative method to conventional methods. Highly stable and hexagonal phase ZnO NPs with average particle size of 40nm were synthesized and characterized by UV-Vis absorption spectroscopy (surface Plasmon resonance), Fourier transform infrared spectroscopy (surface functionalities), X-ray Diffraction analysis (crystallinity), TEM and SEM (size and morphology), Energy Dispersive X-ray spectroscopy (elemental composition), Thermogravimetric analysis (weight loss) and Zeta potential (stability). The preliminary phytochemical experiments identify the possible chemical groups present in leaves extract. The photocatalytic properties of ZnO NPs were studied using UV-Vis spectroscopy by exposing methyl orange to sunlight and it is found to be degraded up to 93.5% within 2h. The COD values were significantly reduced from 5600mg/L to 374mg/L after 100min of solar radiation. The hemolytic activity of synthesized zinc oxide nanoparticles was performed on human erythrocyte cells. Thus the present study provides a simple and eco-friendly method for the preparation of multifunctional property of ZnO NPs utilizing the biosynthetic route. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of Fe-doping on the structural, optical and magnetic properties of ZnO nanoparticles

International Nuclear Information System (INIS)

Liu Changzhen; Meng Dawei; Pang Haixia; Wu Xiuling; Xie Jing; Yu Xiaohong; Chen Long; Liu Xiaoyang

2012-01-01

Zn 1–x Fe x O (x=0–0.05) nanoparticles were synthesized without a catalyst by a two-step method. Fe was doped into ZnO by a source of metallic Fe sheets in a solid–liquid system at 80 °C, and the Zn 1−x Fe x O nanoparticles were obtained by annealing at 300 °C. X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy were used to characterize the structural properties of the as-grown Zn 1−x Fe x O. The optical properties were determined by Infrared and Ultraviolet–visible spectroscopy. The results confirm that the crystallinity of the ZnO is deteriorated due to Fe-doping. XPS results show that there is a mixture of Fe 0+ and the Fe 3+ in the representative Zn 0.95 Fe 0.05 O sample. The optical band gap of Zn 1−x Fe x O is enhanced with increasing of Fe-doping. Room temperature ferromagnetism was observed in all the Fe-doped ZnO samples. - Highlights: ► Zn 1−x Fe x O nanoparticles were synthesized with a simple two-step method. ► The Zn 1−x Fe x O predecessors were synthesized at a low temperature. ► Fe element was readily doped from the source of metallic Fe sheet. ► All the Fe doping ZnO samples have room temperature ferromagnetism. ► The structural and properties of the Zn 1−x Fe x O are regular with different x.

Highly efficient green light harvesting from Mg doped ZnO nanoparticles: Structural and optical studies

Energy Technology Data Exchange (ETDEWEB)

Sharma, Sarla, E-mail: mail2sarlasharma@gmail.com [Department of Physics, University of Rajasthan, Jaipur 302055 (India); Vyas, Rishi [Department of Physics, Malaviya National Institute of Technology, Jaipur 302017 (India); Sharma, Neha [Department of Physics, University of Rajasthan, Jaipur 302055 (India); Singh, Vidyadhar [Okinawa Institute of Science and Technology, Graduate University, Okinawa 9040495 (Japan); Singh, Arvind [Department of Physics, Institute of Chemical Technology, Mumbai 400 019 (India); Kataria, Vanjula; Gupta, Bipin Kumar [National Physical Laboratory (CSIR), New Delhi 110012 (India); Vijay, Y.K. [Department of Physics, University of Rajasthan, Jaipur 302055 (India)

2013-03-05

Graphical abstract: Demonstration of highly efficient green light emission harvesting from Mg doped ZnO nanoparticles were synthesized via facile wet chemical route with an average particle size ∼15 nm. The resulted nanoparticles exhibit intense green emission peaking at 530 nm upon 325 nm excitation. The photoluminescence (PL) intensity of visible emission depends upon the doping concentration of Mg. The PL intensity was found maximum up to 4% doping of Mg and beyond it exhibits a decrees in emission. The obtained highly luminescent green emission of ZnO nanoparticle would be an ultimate choice for next generation optoelectronics device materials. Highlights: ► Zn{sub 1−x}Mg{sub x}O nanoparticles were prepared by mechanochemical processing. ► High blue emission intensity was observed contrary to previous reports. ► Blue emission is suggested to be originating from the high density of defects. ► Defect density in as-milled condition is very high resulting in high emission. ► Mg promoted non-radiative recombination and lowered intensities. -- Abstract: Highly efficient green light emission was observed from Mg doped ZnO nanoparticles synthesized via facile wet chemical route with an average particle size ∼15 nm. The XRD analysis confirmed the growth of wurtzite phase of ZnO nanoparticles. Moreover, the optical properties of these nanoparticles were investigated by different spectroscopic techniques. The resulted nanoparticles exhibit intense green emission peaking at 530 nm (2.34 eV) upon 325 nm (3.81 eV) excitation. The photoluminescence (PL) intensity of visible emission depends upon the doping concentration of Mg. The PL intensity was found maximum up to 4% doping of Mg, and beyond it exhibits a decrees in emission. Furthermore, by varying the band gap from 3.50 to 3.61 eV, the PL spectra showed a near band edge (NBE) emission at wavelength around 370 nm (3.35 eV) and a broad deep level emission in the visible region. The obtained highly

Investigation on structural and electrical properties of Fe doped ZnO nanoparticles synthesized by solution combustion method

International Nuclear Information System (INIS)

Ram, Mast; Bala, Kanchan; Sharma, Hakikat; Kumar, Arun; Negi, N. S.

2016-01-01

In the present study, nanoparticles of Fe doped zinc oxide (ZnO) [Zn_1_-_xFe_xO where x=0.0, 0.01, 0.02, 0.03 and 0.05] were prepared by cost effective solution combustion method. The powder X-ray diffractometry confirms the formation of single phase wurtzite structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the micrsostructure of Fe-doped ZnO nanoparticles. The DC electrical conductivity was found to increase with temperature and measurement was carried out in the temperature range of 300-473K. DC electrical conductivity increases with temperature and decreases with Fe doping concentration.

Inhibition of growth of S. epidermidis by hydrothermally synthesized ZnO nanoplates

Science.gov (United States)

Abinaya, C.; Mayandi, J.; Osborne, J.; Frost, M.; Ekstrum, C.; Pearce, J. M.

2017-07-01

The antibacterial effect of zinc oxide (ZnO#1) as prepared and annealed (ZnO#2) at 400 °C, Cu doped ZnO (CuZnO), and Ag doped ZnO (AgZnO) nanoplates on Staphylococcus epidermidis was investigated for the inhibition and inactivation of cell growth. The results shows that pure ZnO and doped ZnO samples exhibited antibacterial activity against Staphylococcus epidermidis (S. epidermidis) as compared to tryptic soy broth (TSB). Also it is observed that S. epidermidis was extremely sensitive to treatment with ZnO nanoplates and it is clear that the effect is not purely depend on Cu/Ag. Phase identification of a crystalline material and unit cell dimensions were studied by x-ray powder diffraction (XRD). The scanning electron microscopy (SEM) provides information on sample’s surface topography and the EDX confirms the presence of Zn, O, Cu and Ag. X-ray photo-electron spectroscopy (XPS) was used to analyze the elemental composition and electronic state of the elements that exist within the samples. These studies confirms the formation of nanoplates and the presence of Zn, O, Ag, Cu with the oxidation states  +2, -2, 0 and  +2 respectively. These results indicates promising antibacterial applications of these ZnO-based nanoparticles synthesized with low-cost hydrothermal methods.

In-situ PXRD studies of ZnO nanoparticle growth: How do various salts influence the hydrothermal growth of ZnO?

DEFF Research Database (Denmark)

Bøjesen, Espen Drath

ZnO is a material of great scientific and everyday relevance; it is used widely in all sorts of application. Synthesis of ZnO nanoparticles can be performed by a wide assortment of methods and a tremendous variety of sizes and shapes, it has been suggested that ZnO is the one known compound showing...... the broadest range of nanostructures. Previously many different in-situ characterization methods have been used to investigate the ZnO formation under various synthesis conditions; these include UV-VIS and SAXS. These methods were primarily used to give information on particle size of ZnO formed using soft...... chemical methods and non-aqueous solvents. In our work we have studied the formation of ZnO during hydrothermal syntheses using in-situ powder X-ray diffraction, thus enabling us to extract crystallographic as well as microstructural information. The data was analyzed using Rietveld refinement and whole...

Microwave-assisted silica coating and photocatalytic activities of ZnO nanoparticles

International Nuclear Information System (INIS)

Siddiquey, Iqbal Ahmed; Furusawa, Takeshi; Sato, Masahide; Suzuki, Noboru

2008-01-01

A new and rapid method for silica coating of ZnO nanoparticles by the simple microwave irradiation technique is reported. Silica-coated ZnO nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), CHN elemental analysis and zeta potential measurements. The FT-IR spectra and XPS clearly confirmed the silica coating on ZnO nanoparticles. The results of XPS analysis showed that the elements in the coating at the surface of the ZnO nanoparticles were Zn, O and Si. HR-TEM micrographs revealed a continuous and uniform dense silica coating layer of about 3 nm in thickness on the surface of ZnO nanoparticles. In addition, the silica coating on the ZnO nanoparticles was confirmed by the agreement in the zeta potential of the silica-coated ZnO nanoparticles with that of SiO 2 . The results of the photocatalytic degradation of methylene blue (MB) in aqueous solution showed that silica coating effectively reduced the photocatalytic activity of ZnO nanoparticles. Silica-coated ZnO nanoparticles showed excellent UV shielding ability and visible light transparency

Controllable synthesis of ZnO nanoparticles with high intensity visible photoemission and investigation of its mechanism

International Nuclear Information System (INIS)

Lv Yunbo; Xiao Wen; Li Weiyan; Xue Junmin; Ding Jun

2013-01-01

ZnO is known as a good photoluminescent semiconductor due to its ability to emit visible light. However, the visible emission mechanism is still under debate. In this work, we have successfully synthesized nanoparticles using LiOH, KOH and NaOH as bases and have achieved visible emission of various colours, such as blue, cyan, green and orange. We demonstrate that LiOH is the most efficient base to control the properties of ZnO nanoparticle emission by varying LiOH concentration. Moreover, detailed studies by TEM, UV and XRD show that ZnO particle size plays an important role in the colour of the emitted light and smaller particles tend to emit shorter wavelength photons. The visible emission is suggested to arise from an electron transition from the conduction band to a deep-trapped defect state. Our experimental results suggest the presence of oxygen vacancies on the ZnO nanoparticle surface. (paper)

The effects of Mg incorporation and annealing temperature on the physicochemical properties and antibacterial activity against Listeria monocytogenes of ZnO nanoparticles

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Shadan, Nima; Ziabari, Ali Abdolahzadeh; Meraat, Rafieh; Jalali, Kamyar Mazloum

2017-02-01

In this paper, Mg-doped ZnO nanoparticles were synthesized by the facile sol-gel method. The crystalline structure, characteristic absorption bands and morphology of the obtained Mg-doped ZnO nanoparticles were studied by XRD, FTIR and TEM. The thermal degradation behaviour of the samples was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). The effect of Mg concentrations and annealing temperatures on the antibacterial properties of the obtained nanoparticles was investigated in detail. The results indicated that doping Mg ions into ZnO lattice could enhance its antibacterial activity. Antibacterial assay demonstrated that Mg-doped ZnO with 7% Mg content annealed at 400 ∘C had the strongest antibacterial activity against Listeria monocytogenes (98.7%). This study indicated that the inhibition rate of ZnO nanoparticles increased with the formation of granular structure and the decrease of ZnO size due to the doping of Mg ions into the ZnO lattice.

The Influences of Cell Type and ZnO Nanoparticle Size on Immune Cell Cytotoxicity and Cytokine Induction

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Thurber Aaron

2009-01-01

Full Text Available Abstract Nanotechnology represents a new and enabling platform that promises to provide a range of innovative technologies for biological applications. ZnO nanoparticles of controlled size were synthesized, and their cytotoxicity toward different human immune cells evaluated. A differential cytotoxic response between human immune cell subsets was observed, with lymphocytes being the most resistant and monocytes being the most susceptible to ZnO nanoparticle-induced toxicity. Significant differences were also observed between previously activated memory lymphocytes and naive lymphocytes, indicating a relationship between cell-cycle potential and nanoparticle susceptibility. Mechanisms of toxicity involve the generation of reactive oxygen species, with monocytes displaying the highest levels, and the degree of cytotoxicity dependent on the extent of nanoparticle interactions with cellular membranes. An inverse relationship between nanoparticle size and cytotoxicity, as well as nanoparticle size and reactive oxygen species production was observed. In addition, ZnO nanoparticles induce the production of the proinflammatory cytokines, IFN-γ, TNF-α, and IL-12, at concentrations below those causing appreciable cell death. Collectively, these results underscore the need for careful evaluation of ZnO nanoparticle effects across a spectrum of relevant cell types when considering their use for potential new nanotechnology-based biological applications.

Electrosynthesis and characterization of ZnO nanoparticles as inorganic component in organic thin-film transistor active layers

International Nuclear Information System (INIS)

Picca, Rosaria Anna; Sportelli, Maria Chiara; Hötger, Diana; Manoli, Kyriaki; Kranz, Christine; Mizaikoff, Boris; Torsi, Luisa; Cioffi, Nicola

2015-01-01

Highlights: • PSS-capped ZnO NPs were synthesized via a green electrochemical-thermal method • The influence of electrochemical conditions and temperature was studied • Spectroscopic data show that PSS functionalities are retained in the annealed NPs • Nanostructured ZnO improved the performance of P3HT-based thin film transistors - Abstract: ZnO nanoparticles have been prepared via a green electrochemical synthesis method in the presence of a polymeric anionic stabilizer (poly-sodium-4-styrenesulfonate, PSS), and then applied as inorganic component in poly-3-hexyl-thiophene thin-film transistor active layers. Different parameters (i.e. current density, electrolytic media, PSS concentration, and temperature) influencing nanoparticle synthesis have been studied. The resulting nanomaterials have been investigated by transmission electron microscopy (TEM) and spectroscopic techniques (UV-Vis, infrared, and x-ray photoelectron spectroscopies), assessing the most suitable conditions for the synthesis and thermal annealing of nanostructured ZnO. The proposed ZnO nanoparticles have been successfully coupled with a poly-3-hexyl-thiophene thin-film resulting in thin-film transistors with improved performance.

Fast synthesize ZnO quantum dots via ultrasonic method.

Science.gov (United States)

Yang, Weimin; Zhang, Bing; Ding, Nan; Ding, Wenhao; Wang, Lixi; Yu, Mingxun; Zhang, Qitu

2016-05-01

Green emission ZnO quantum dots were synthesized by an ultrasonic sol-gel method. The ZnO quantum dots were synthesized in various ultrasonic temperature and time. Photoluminescence properties of these ZnO quantum dots were measured. Time-resolved photoluminescence decay spectra were also taken to discover the change of defects amount during the reaction. Both ultrasonic temperature and time could affect the type and amount of defects in ZnO quantum dots. Total defects of ZnO quantum dots decreased with the increasing of ultrasonic temperature and time. The dangling bonds defects disappeared faster than the optical defects. Types of optical defects first changed from oxygen interstitial defects to oxygen vacancy and zinc interstitial defects. Then transformed back to oxygen interstitial defects again. The sizes of ZnO quantum dots would be controlled by both ultrasonic temperature and time as well. That is, with the increasing of ultrasonic temperature and time, the sizes of ZnO quantum dots first decreased then increased. Moreover, concentrated raw materials solution brought larger sizes and more optical defects of ZnO quantum dots. Copyright © 2015 Elsevier B.V. All rights reserved.

Complete transformation of ZnO and CuO nanoparticles in ...

Science.gov (United States)

Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24 h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy results revealed that Zn speciation profiles of 30 nm and 80 nm ZnO nanoparticles, and ZnSO4- exposed cells were almost identical with the prevailing species being Zn-cysteine. This suggests that ZnO nanoparticles are rapidly transformed during a standard in vitro toxicological assay, and are sequestered intracellularly, analogously to soluble Zn. Complete transformation of ZnO in the test conditions was further supported by almost identical Zn spectra in medium to which ZnO nanoparticles or ZnSO4 was added. Likewise, Cu XANES spectra for CuO and CuSO4-exposed cells and cell culture media were similar. These results together with our observation on similar toxicological profiles of ZnO and soluble Zn, and CuO and soluble Cu, underline the importance of dissolution and subsequent transformation of ZnO and CuO nanoparticles during toxicological testing and provide evidence that the nano-specific effect of ZnO and CuO nanoparticulates is negligible in this system. We strongly suggest to account for this aspect when interpreting the toxicological results of ZnO and CuO nanoparticles. Although a number of studies have discussed the transformation of nanoparticles during

Rapid thermal melted TiO2 nano-particles into ZnO nano-rod and its application for dye sensitized solar cells

International Nuclear Information System (INIS)

Chao, Ching-Hsun; Chang, Chi-Lung; Chan, Chien-Hung; Lien, Shui-Yang; Weng, Ko-Wei; Yao, Kuo-Shan

2010-01-01

TiO 2 nano-particles with an anchored ZnO nano-rod structure were synthesized using the hydrothermal method to grow ZnO nano-rods and coated TiO 2 nano-particles on ZnO nano-rods using the rapid thermal annealing method on ITO conducting glass pre-coated with nano porous TiO 2 film. The XRD study showed that there was little difference in crystal composition for various types of TiO 2 nano-particles anchored to ZnO nano-rods. The as-prepared architecture was characterized using field-emission scanning electron microscopy (FE-SEM). Films with TiO 2 nano-particles anchored to ZnO nano-rods were used as electrode materials to fabricate dye sensitized solar cells (DSSCs). The best solar energy conversion efficiency of 2.397% was obtained by modified electrode material, under AM 1.5 illumination, achieved up to J sc = 15.382 mA/cm 2 , V oc = 0.479 V and fill factor = 32.8%.

Positron annihilation studies in ZnO nanoparticles

Science.gov (United States)

Sharma, S. K.; Pujari, P. K.; Sudarshan, K.; Dutta, D.; Mahapatra, M.; Godbole, S. V.; Jayakumar, O. D.; Tyagi, A. K.

2009-04-01

We report results on positron annihilation spectroscopic (PAS) studies using lifetime and coincidence Doppler broadening techniques in zinc oxide (ZnO) nanoparticles (4 to 40 nm) synthesized by solid state pyrolytic reaction followed by annealing in the temperature range of 200 ∘C to 800 ∘C. Positron lifetime in the nanoparticles are observed to be higher than bulk lifetime in all the cases. Theoretical calculation of lifetime indicates the presence of either Zn or (Zn, O) vacancy clusters which migrate and anneal out at high temperature. Comparison of ratio spectra from coincidence Doppler broadening measurement and calculated electron momentum distribution indicates the presence of either Zn or (Zn, O) vacancies. In addition, photoluminescence (PL) measurements have been carried out to examine the role of defects on the intensity of emission in the visible region.

Synthesis and Characterization of Nanoparticles and Nanocomposite of ZnO and MgO by Sonochemical Method and their Application for Zinc Polycarboxylate Dental Cement Preparation

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Mohammad Ali Karimi

2011-01-01

Full Text Available This paper discusses the synthesis of nanoparticles of ZnO and MgO and ZnO/MgO nanocomposite by the sonochemical method. At first, nanoparticles were synthesized by the reaction of Zn(CHCOO32 and Mg(CHCOO32 with tetramethylammonium hydroxide (TMAH in the presence of polyvinyl pyrrolidone (PVP and constant frequency ultrasonic waves (sonochemical method. Then, ZnO/MgO nanocomposite was prepared through reaction of magnesium acetate with TMAH in the presence of ZnO nanoparticles and PVP as structure director using ultrasonic assisted method. After filtration, the synthesized solution was obtained containing magnesium hydroxide in the presence of ZnO nanoparticles. It was calcinated at the temperature of 550 ºC, so that ZnO/MgO nanocomposite could be produced. The effects of different parameters on particle size and morphology of final ZnO and MgO powders and ZnO/MgO nanocomposite were optimized by ‘‘one at a time’’ method. Under optimum conditions, spongy shaped, uniformed and homogeneous nanostructured zinc oxide and magnesium oxide powders were obtained with particle sizes of 25–50 and 30-60 nm, respectively. ZnO/MgO nanocomposite was also obtained with more spongy morphology and particle size about 65 nm. Both synthesized ZnO and MgO nanoparticles and ZnO/MgO nanocomposite were successfully applied to the preparation of zinc polycarboxylate dental cement.

Fabrication of Well-Aligned ZnO Nanorods Using a Composite Seed Layer of ZnO Nanoparticles and Chitosan Polymer.

Science.gov (United States)

Khun, Kimleang; Ibupoto, Zafar Hussain; AlSalhi, Mohamad S; Atif, Muhammad; Ansari, Anees A; Willander, Magnus

2013-09-30

In this study, by taking the advantage of both inorganic ZnO nanoparticles and the organic material chitosan as a composite seed layer, we have fabricated well-aligned ZnO nanorods on a gold-coated glass substrate using the hydrothermal growth method. The ZnO nanoparticles were characterized by the Raman spectroscopic techniques, which showed the nanocrystalline phase of the ZnO nanoparticles. Different composites of ZnO nanoparticles and chitosan were prepared and used as a seed layer for the fabrication of well-aligned ZnO nanorods. Field emission scanning electron microscopy, energy dispersive X-ray, high-resolution transmission electron microscopy, X-ray diffraction, and infrared reflection absorption spectroscopic techniques were utilized for the structural characterization of the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods on a gold-coated glass substrate. This study has shown that the ZnO nanorods are well-aligned, uniform, and dense, exhibit the wurtzite hexagonal structure, and are perpendicularly oriented to the substrate. Moreover, the ZnO nanorods are only composed of Zn and O atoms. An optical study was also carried out for the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods, and the obtained results have shown that the fabricated ZnO nanorods exhibit good crystal quality. This study has provided a cheap fabrication method for the controlled morphology and good alignment of ZnO nanorods, which is of high demand for enhancing the working performance of optoelectronic devices.

Fabrication of Well-Aligned ZnO Nanorods Using a Composite Seed Layer of ZnO Nanoparticles and Chitosan Polymer

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Anees A. Ansari

2013-09-01

Full Text Available In this study, by taking the advantage of both inorganic ZnO nanoparticles and the organic material chitosan as a composite seed layer, we have fabricated well-aligned ZnO nanorods on a gold-coated glass substrate using the hydrothermal growth method. The ZnO nanoparticles were characterized by the Raman spectroscopic techniques, which showed the nanocrystalline phase of the ZnO nanoparticles. Different composites of ZnO nanoparticles and chitosan were prepared and used as a seed layer for the fabrication of well-aligned ZnO nanorods. Field emission scanning electron microscopy, energy dispersive X-ray, high-resolution transmission electron microscopy, X-ray diffraction, and infrared reflection absorption spectroscopic techniques were utilized for the structural characterization of the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods on a gold-coated glass substrate. This study has shown that the ZnO nanorods are well-aligned, uniform, and dense, exhibit the wurtzite hexagonal structure, and are perpendicularly oriented to the substrate. Moreover, the ZnO nanorods are only composed of Zn and O atoms. An optical study was also carried out for the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods, and the obtained results have shown that the fabricated ZnO nanorods exhibit good crystal quality. This study has provided a cheap fabrication method for the controlled morphology and good alignment of ZnO nanorods, which is of high demand for enhancing the working performance of optoelectronic devices.

Sonochemical synthesis and photocatalytic property of zinc oxide nanoparticles doped with magnesium(II)

International Nuclear Information System (INIS)

Lu, Xianyong; Liu, Zhaoyue; Zhu, Ying; Jiang, Lei

2011-01-01

Highlights: → Mg-doped ZnO nanoparticles were synthesized by sonochemical strategy. → Mg-doped ZnO nanoparticles present good photocatalytic properties. → The change of band gap contributes to their high efficiency in photocatalyst. -- Abstract: Mg-doped ZnO nanoparticles were successfully synthesized by sonochemical method. The products were characterized by scan electron microscopy (SEM) and X-ray powder diffraction (XRD). SEM images revealed that ZnO doped with Mg(II) nanoparticles and ZnO nanoparticles synthesized by the same strategy all had spherical topography. XRD patterns showed that the doped nanoparticles had the same crystals structures as the pure ZnO nanoparticles. The Mg-doped ZnO nanoparticles had larger lattice volume than the un-doped nanoparticles. X-ray photoelectron spectroscopy (XPS) not only demonstrated the moral ratio of Mg and Zn element on the surface of nanoparticles, but their valence in nanoparticles as well. The Mg-doped ZnO nanoparticles presented good properties in photocatalyst compared with pure ZnO nanoparticles.

Structural characteristics and UV-light enhanced gas sensitivity of La-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Ge Chunqiao; Xie Changsheng; Hu Mulin; Gui Yanghai; Bai Zikui; Zeng Dawen

2007-01-01

La-doped ZnO nanoparticles were synthesized by sol-gel method starting from zinc acetate dihydrate, lanthanum sesquioxide, alcohol and nitric acid. The crystal structure and morphology of the nanoparticles were characterized by XRD, FESEM, respectively. The thermal decomposition behavior of the the ZnO-based xerogel was detected by TG-DSC. The results show that as-prepared nanoparticles with the hexagonal wurtzite contain the adsorbed water and some organic compounds below 300 o C, which is the key to the calcinations of the ZnO-based xerogel. Pure ZnO and La-doped ZnO thick film sensors were prepared and tested for specific sensitivity to alcohol and benzene with (and without) UV-light excitation. Among all, 10 at.%La-ZnO-based sensors are significantly sensitive to 100 ppm alcohol and 100 ppm benzene. There is an obvious enhancement of the gas-sensing performances with UV-light excitation. That is, the sensitivity to 100 ppm benzene rises twice. The observed sensitivity to alcohol and benzene could be explained with the surface adsorption theory and the conduction-band theory

Direct growth of CdSe nanorods on ITO substrates by co-anchoring of ZnO nanoparticles and ethylenediamine

International Nuclear Information System (INIS)

Pan Shangke; Xu Tingting; Venkatesan, Swaminathan; Qiao Qiquan

2012-01-01

To grow CdSe nanorods directly onto indium tin oxide (ITO) substrates, a ZnO buffer layer composed of nanoparticles with diameter of ∼30–40 nm was prepared by spin coating ZnO sol–gel solution onto the ITO substrates. CdSe nanorods were then successfully in situ grown onto ITO substrates with diameter of ∼30–40 nm and length of ∼120–160 nm using solvothermal method in which CdSe·0.5en (en = ethylenediamine) acted as solution precursor. The in situ synthesized CdSe nanorods were conformed and characterized by atomic force microscope and electron microscopy. The mechanism of such in situ CdSe growth was understood as ZnO nanoparticles anchored en onto ITO substrates, while en linked CdSe with ZnO.

ZnO nanoparticles (ZnO-NPs) and their antifungal activity against coffee fungus Erythricium salmonicolor

Science.gov (United States)

Arciniegas-Grijalba, P. A.; Patiño-Portela, M. C.; Mosquera-Sánchez, L. P.; Guerrero-Vargas, J. A.; Rodríguez-Páez, J. E.

2017-06-01

In this work, a methodology of synthesis was designed to obtain ZnO nanoparticles (ZnO NPs) in a controlled and reproducible manner. The nanoparticles obtained were characterized using infrared spectroscopy, X-ray diffraction, and transmission electron microscopy (TEM). Also, we determined the antifungal capacity in vitro of zinc oxide nanoparticles synthesized, examining their action on Erythricium salmonicolor fungy causal of pink disease. To determine the effect of the quantity of zinc precursor used during ZnO NPs synthesis on the antifungal capacity, 0.1 and 0.15 M concentrations of zinc acetate were examined. To study the inactivation of the mycelial growth of the fungus, different concentrations of ZnO NPs of the two types of synthesized samples were used. The inhibitory effect on the growth of the fungus was determined by measuring the growth area as a function of time. The morphological change was observed with high-resolution optical microscopy (HROM), while TEM was used to observe changes in its ultrastructure. The results showed that a concentration of 9 mmol L-1 for the sample obtained from the 0.15 M and at 12 mmol L-1 for the 0.1 M system significantly inhibited growth of E. salmonicolor. In the HROM images a deformation was observed in the growth pattern: notable thinning of the fibers of the hyphae and a clumping tendency. The TEM images showed a liquefaction of the cytoplasmic content, making it less electron-dense, with the presence of a number of vacuoles and significant detachment of the cell wall.

Nanoparticles of ZnO doped with Mn: structural and morphological characteristics

Energy Technology Data Exchange (ETDEWEB)

Bonifacio, Maria Aparecida Ribeiro; Lira, Helio de Lucena; Gama, Lucianna, E-mail: m_aparecidaribeiro@yahoo.com.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Neiva, Laedna Souto [Universidade Federal do Cariri (UFCA), Juazeiro do Norte, CE (Brazil). Unidade Academica de Materiais; Kiminami, Ruth H. G. A. [Universidade Federal de Sao Carlos (USCar), SP (Brazil). Departamento de Engenharia de Materiais

2017-07-15

In this study, the effects of dopant concentrations on the structural and morphological characteristics of Zn{sub 1-x}Mn{sub x} O powders (x= 0.025, 0.05, 0.075, and 0.1 mole) synthesized by the Pechini method has been investigated. The powder was characterized by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) specific surface, energy dispersive X-ray (EDX), scanning electron microscopy (SEM) and Spectroscopy with Fourier transform (FTIR). An XRD analysis of the powder showed the formation of ZnO phase with a typical single phase wurtzite structure. The EDX analysis revealed Mn incorporated in the ZnO structure. The particle size calculated by BET ranged from 24 to 63 nm, confirming the nanometric size of the powder particles. The SEM analysis revealed irregular shaped particle agglomerates and the presence of nanosheets. From FTIR it was confirmed the wurtzite structure in ZnO and ZnO nanoparticles doped with Mn. (author)

Effect of the pillar ligand on preventing agglomeration of ZnO nanoparticles prepared from Zn(II metal-organic frameworks

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Maryam Moeinian

2016-01-01

Full Text Available Metal-Organic Frameworks (MOFs represent a new class of highly porous materials. On this regard,  two nano porous metal-organic frameworks of [Zn2(1,4-bdc2(H2O2∙(DMF2]n (1 and [Zn2(1,4-bdc2(dabco]·4DMF·1⁄2H2O (2, (1,4-bdc = benzene-1,4-dicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane and DMF = N,N-dimethylformamide were synthesized and characterized. They were used for preparation of ZnO nanomaterials. With calcination of 1, agglomerated ZnO nanoparticles could be fabricated, but by the same process on 2, the tendency of ZnO nanoparticles to agglomeration was decreased. In addition, the ZnO nanoparticles prepared from compound 2 had smaller diameter than those obtained from compound 1. In fact, the role of organic dabco ligands in 2 is similar to the role of polymeric stabilizers in formation of nanoparticles. Finally, considering the various applications of ZnO nanomaterials such as light-emitting diodes, photodetectors, photodiodes, gas sensors and dye-sensitized solar cells (DSSCs, it seems that preparation of ZnO nanomaterials from their MOFs could be one of the simple and effective methods which may be applied for preparation of them.

Synthesis of Colloidal ZnO Nanoparticles and Deposit of Thin Films by Spin Coating Technique

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Jose Alberto Alvarado

2013-01-01

Full Text Available ZnO colloidal nanoparticles were synthesized, the average size of these nanoparticles is around 25 nm with hexagonal form. It was noted that stabilization depends directly on the purifying process; in this work we do not change the nature of the solution as a difference from Meulekamp's method, and we do not use any alkanes to remove the byproducts; only a centrifuge to remove those ones was used, thereby the stabilization increases up to 24 days. It is observed from the results that only three times of washing is enough to prevent the rapid aging process. The effect of annealing process on the composition, size, and geometrical shape of ZnO nanoparticles was studied in order to know whether the annealing process affects the crystallization and growth of the nanoparticles. After the synthesis, the colloidal nanoparticles were deposited by spin coating technique showing that the formed nanoparticles have no uniformly deposition pattern. But is possible to deposit those ones in glass substrates. A possible deposition process of the nanoparticles is proposed.

Spectroscopic characterization and docking studies of ZnO nanoparticle modified with BSA

International Nuclear Information System (INIS)

Ledesma, Ana E.; Chemes, Doly María; Frías, María de los Angeles; Guauque Torres, Maria del Pilar

2017-01-01

Highlights: • The ZnO NPs have synthesized at moderate temperature and conjugated with BSA to elucidate the characteristics of best binding site in the protein cavity. • The Docking studies have successfully applied to identify the amino acids residues involved in the interaction. • The cytotoxicity of ZnO NPs and ZnO-BSA NPs and esterase-like activity of the protein have evaluated, with very promising results for medical applications. - Abstract: Nanoparticles (NP) into a biological environment are an interesting topic for diagnosis and therapy in applications for medicine or environment and the knowledge about this interaction is important from the perspective of safe use of nanomaterials. In the current study, we characterized the type of interaction and the orientation of bovine serum albumin (BSA) adsorbed on ZnO nanoparticle surfaces as a function of size, using molecular docking. To probe experimentally different theoretical hypothesis about the interaction, ZnO-NPs were prepared in aqueous solution, and then were bioconjugated with BSA. Transmission electron microscopy (TEM) and Raman spectroscopy confirm the spherical shape of NP and the irreversible adsorption of BSA on NP surface. Raman and Infrared spectroscopy (FTIR) reveal that BSA interaction with ZnO nanoparticle produced a conformational rearrangement into protein, observing changes in Tyr and Trp environment, a minor percentage of α-helix structure and a more extended chain. The fluorescence analysis demonstrated that when BSA concentration higher than 30 μM is used the signal due to the self-oligomerization of protein overlaps with the ZnO nanoparticle emission. The results predicted that the most probable interaction site is near to domain IB and IIA and ionic interactions are the major responsible for the binding. Thermal stability studies reveals that the denaturalization temperature of BSA increase from 57 °C to 65 °C in presence of ZnO NP and their esterase-like activity was

Spectroscopic characterization and docking studies of ZnO nanoparticle modified with BSA

Energy Technology Data Exchange (ETDEWEB)

Ledesma, Ana E., E-mail: anael@unse.edu.ar [CITSE-UNSE, CONICET, FCEyT, RN 9, km 1125, 4206 Santiago del Estero (Argentina); Chemes, Doly María [INQUINOA, UNT, CONICET, FBQyF, San Lorenzo 456, San Miguel de Tucumán CPA T4000ILI, Tucumán (Argentina); Frías, María de los Angeles [Laboratory of Biointerphases and Biomimetic Systems, (CITSE) National University of Santiago del Estero and CONICET, 4206, RN 9- Km 1125, Santiago del Estero (Argentina); Guauque Torres, Maria del Pilar [CITSE-UNSE, CONICET, FCEyT, RN 9, km 1125, 4206 Santiago del Estero (Argentina)

2017-08-01

Highlights: • The ZnO NPs have synthesized at moderate temperature and conjugated with BSA to elucidate the characteristics of best binding site in the protein cavity. • The Docking studies have successfully applied to identify the amino acids residues involved in the interaction. • The cytotoxicity of ZnO NPs and ZnO-BSA NPs and esterase-like activity of the protein have evaluated, with very promising results for medical applications. - Abstract: Nanoparticles (NP) into a biological environment are an interesting topic for diagnosis and therapy in applications for medicine or environment and the knowledge about this interaction is important from the perspective of safe use of nanomaterials. In the current study, we characterized the type of interaction and the orientation of bovine serum albumin (BSA) adsorbed on ZnO nanoparticle surfaces as a function of size, using molecular docking. To probe experimentally different theoretical hypothesis about the interaction, ZnO-NPs were prepared in aqueous solution, and then were bioconjugated with BSA. Transmission electron microscopy (TEM) and Raman spectroscopy confirm the spherical shape of NP and the irreversible adsorption of BSA on NP surface. Raman and Infrared spectroscopy (FTIR) reveal that BSA interaction with ZnO nanoparticle produced a conformational rearrangement into protein, observing changes in Tyr and Trp environment, a minor percentage of α-helix structure and a more extended chain. The fluorescence analysis demonstrated that when BSA concentration higher than 30 μM is used the signal due to the self-oligomerization of protein overlaps with the ZnO nanoparticle emission. The results predicted that the most probable interaction site is near to domain IB and IIA and ionic interactions are the major responsible for the binding. Thermal stability studies reveals that the denaturalization temperature of BSA increase from 57 °C to 65 °C in presence of ZnO NP and their esterase-like activity was

Ultra-high sensitive hydrazine chemical sensor based on low-temperature grown ZnO nanoparticles

International Nuclear Information System (INIS)

Mehta, S.K.; Singh, Kulvinder; Umar, Ahmad; Chaudhary, G.R.; Singh, Sukhjinder

2012-01-01

Graphical abstract: Systematic representation of the fabricated amperometric hydrazine chemical sensor based on ZnO NPs/Au modified electrode. Highlights: ► Synthesis of well-crystalline ZnO NPs has been achieved in aqueous solution. ► ZnO NPs act as efficient electron mediators for hydrazine sensor. ► Extremely high sensitivity and low-detection limit have been obtained. - Abstract: Using well-crystalline ZnO nanoparticles (NPs), an ultra high sensitive hydrazine amperometric sensor has been fabricated and reported in this paper. The ZnO NPs have been synthesized by very simple aqueous solution process at 90 °C and characterized in detail in terms of their morphological, compositional, structural and optical properties. The detailed investigations reveal that the synthesized products are well-crystalline NPs, possessing wurtzite hexagonal phase and exhibit good optical properties. The fabricated amperometric hydrazine sensor exhibits ultra-high sensitivity of ∼97.133 μA cm −2 μM −1 and very low-detection limit of 147.54 nM. To the best of our knowledge, this is the first report in which an ultra-high sensitivity and low-detection limit have been obtained for the hydrazine chemical sensor based on ZnO nanostructures.

Oxygen vacancy induced by La and Fe into ZnO nanoparticles to modify ferromagnetic ordering

International Nuclear Information System (INIS)

Verma, Kuldeep Chand; Kotnala, R.K.

2016-01-01

We reported long-range ferromagnetic interactions in La doped Zn 0.95 Fe 0.05 O nanoparticles that mediated through lattice defects or vacancies. Zn 0.92 Fe 0.05 La 0.03 O (ZFLaO53) nanoparticles were synthesized by a sol–gel process. X-ray fluorescence spectrum of ZFLaO53 detects the weight percentage of Zn, Fe, La and O. X-ray diffraction shows the hexagonal Wurtzite ZnO phase. The Rietveld refinement has been used to calculate the lattice parameters and the position of Zn, Fe, La and O atoms in the Wurtzite unit cell. The average size of ZFLaO53 nanoparticles is 99 nm. The agglomeration type product due to OH ions with La results into ZnO nanoparticles than nanorods that found in pure ZnO and Zn 0.95 Fe 0.05 O sample. The effect of doping concentration to induce Wurtzite ZnO structure and lattice defects has been analyzed by Raman active vibrational modes. Photoluminescence spectra show an abnormal emission in both UV and visible region, and a blue shift at near band edge is formed with doping. The room temperature magnetic measurement result into weak ferromagnetism but pure ZnO is diamagnetic. However, the temperature dependent magnetic measurement using zero-field and field cooling at dc magnetizing field 500 Oe induces long-range ferromagnetic ordering. It results into antiferromagnetic Neel temperature of ZFLaO53 at around 42 K. The magnetic hysteresis is also measured at 200, 100, 50 and 10 K measurement that indicate enhancement in ferromagnetism at low temperature. Overall, the La doping into Zn 0.95 Fe 0.05 O results into enhanced antiferromagnetic interaction as well as lattice defects/vacancies. The role of the oxygen vacancy as the dominant defects in doped ZnO must form Bound magnetic polarons has been described. - Graphical abstract: The long-range ferromagnetic order in Zn 0.92 Fe 0.05 La 0.03 O nanoparticles at low temperature measurements involves oxygen vacancy as the medium of magnetic interactions. - Highlights: • The La and Fe doping

Photocatalytic degradation of Reactive Black 5 and Malachite Green with ZnO and lanthanum doped nanoparticles

International Nuclear Information System (INIS)

Kaneva, N; Bojinova, A; Papazova, K

2016-01-01

Here we report the preparation of ZnO particles with different concentrations of La 3 + doping (0, 0.5 and 1 wt%) via sol-gel method. The nanoparticles are synthesized directly from Zn(CH 3 COO) 2 .2H 2 O in the presence of 1-propanol and triethylamine at 80°C. The conditions are optimized to obtain particles of uniform size, easy to isolate and purify. The nanoparticles are characterized by SEM, XRD and UV-Vis analysis. The photocatalytic properties of pure and La-doped ZnO are studied in the photobleaching of Malachite Green (MG) and Reactive Black 5 (RB5) dyes in aqueous solutions upon UV illumination. It is observed that the rate constant increases with the La loading up to 1 wt%. The doping helps to achieve complete mineralization of MG within a short irradiation time. 1 wt% La-doped ZnO nanoparticles show highest photocatalytic activity. The La 3+ doped ZnO particles degrade faster RB5 than MG. The reason is weaker N=N bond in comparison with the C-C bond between the central carbon atom and N,N-dimethylaminobenzyl in MG. The as-prepared ZnO particles can find practical application in photocatalytic purification of textile wastewaters. (paper)

Preparation of ZnO Nanoparticles and Photocatalytic H2 Production Activity from Different Sacrificial Reagent Solutions

Science.gov (United States)

Peng, Tian-you; Lv, Hong-jin; Zeng, Peng; Zhang, Xiao-hu

2011-08-01

ZnO nanoparticles were synthesized via a direct precipitation method followed by a heterogeneous azeotropic distillation and calcination processes, and then characterized by X-ray power diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption measurement. The effects of Pt-loading amount, calcination temperature, and sacrificial reagents on the photocatalytic H2 evolution efficiency from the present ZnO suspension were investigated. The experimental results indicate that ZnO nanoparticles calcined at 400 °C exhibit the best photoactivity for the H2 production in comparison with the samples calcined at 300 and 500 °C, and the photocatalytic H2 production efficiency from a methanol solution is much higher than that from a triethanolamine solution. It can be ascribed to the oxidization of methanol also contributes to the H2 production during the photochemical reaction process. Moreover, the photocatalytic mechanism for the H2 production from the present ZnO suspension system containing methanol solution is also discussed in detail.

Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers.

Science.gov (United States)

Dybowska, Agnieszka D; Croteau, Marie-Noele; Misra, Superb K; Berhanu, Deborah; Luoma, Samuel N; Christian, Paul; O'Brien, Paul; Valsami-Jones, Eugenia

2011-01-01

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (67Zn) ZnO nanoparticles and measured the uptake of 67Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 μg g(-1)). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 μg g(-1) which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers

Science.gov (United States)

Dybowska, A.D.; Croteau, M.-N.; Misra, S.K.; Berhanu, D.; Luoma, S.N.; Christian, P.; O'Brien, P.; Valsami-Jones, E.

2011-01-01

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (67Zn) ZnO nanoparticles and measured the uptake of 67Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 ??g g-1). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 ??g g-1 which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions. ?? 2010 Elsevier Ltd. All rights reserved.

Efficient photocatalytic performance enhancement in Co-doped ZnO nanowires coupled with CuS nanoparticles

Science.gov (United States)

Li, Wei; Wang, Guojing; Feng, Yimeng; Li, Zhengcao

2018-01-01

In this research, a kind of highly efficient semiconductor photocatalyst was fabricated by depositing CuS nanoparticles uniformly on the surface of Co-doped ZnO nanowires. ZnO nanowires were synthesized by hydrothermal method and CuS nanoparticles were modified by successive ionic layer adsorption and reaction (SILAR). By conducting methyl orange (MO) degradation experiments under the illumination of visible light, the photocatalytic activity of Co-doped ZnO nanowires modified with CuS nanoparticles was found to be nearly three times active when compared to bare ZnO nanowires. Its superior photocatalytic performance has two main reasons. The doped Co2+ ions can inhibit the recombination of photo-generated electron-hole pairs and decrease the optical bandgap, while the p-n heterostructure can enhance the visible light absorption ability and promote the separation of photo-excited charge carriers. Furthermore, the effect of the amount of deposited CuS nanoparticles on the photocatalysis was also investigated. The photocatalytic efficiency firstly raised along with the increment of SILAR cycle times and reached a maximum at 10 cycles but then decreased as the cycle times continue to increase. This originates from that an excessive amount of CuS would not only cover the active reacting sites, but also serve as recombination centers. Overall, this new nanostructure is expected to work as an efficient photocatalyst.

Structural, spectroscopic and anti-microbial inspection of PEG capped ZnO nanoparticles for biomedical applications

Science.gov (United States)

Meshram, J. V.; Koli, V. B.; Kumbhar, S. G.; Borde, L. C.; Phadatare, M. R.; Pawar, S. H.

2018-04-01

Zinc oxide (ZnO) nanoparticles (NPs) have a wide range of biomedical applications. Present study demonstrates the new methodology in sol-gel technology for synthesizing Polyethylene glycol (PEG) capped ZnO NPs and its size effect on anti-microbial activity. The reaction time was increased from 1 h to 5 h for the synthesis of ZnO NPs at 130 °C. The size of PEG capped ZnO NPs is increased from 10 to 84 nm by increasing the reaction upto 5 h. The x-ray diffraction studies and transmission electron microscopy analysis reveals the phase purity and hexagonal wurtzite crystal structure with uniform PEG capping on the surface of ZnO NPs. UV–visible spectroscopy exhibits the peak at 366 nm which is attributed to ZnO NPs. No adverse effect is observed in case of absorbance spectroscopy. Further, Fourier transforms infrared spectroscopy and thermo gravimetric analysis depicts the adsorption of PEG molecules on the ZnO NPs surface. The anti-microbial activities for both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria were studied by optical density (OD) mesurement. The remarkable anti-microbial activity was observed for PEG capped ZnO NPs synthesized at 1 h reaction time showing higher activity in comparison with that synthesized from 2 h to 5 h reaction time. The microbial growth was found to be inhibited after 10 h OD measurement for both the bacteria. The anti-microbial activity may be attributed to the generation of ROS and H2O2. However, these generated species plays a vital role in inhibition of microbial growth. Hence, PEG capped ZnO NPs has promising biomedical applications.

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods.

Science.gov (United States)

Liu, Jinzhang; Notarianni, Marco; Rintoul, Llew; Motta, Nunzio

2014-01-01

One-dimensional single crystal incorporating functional nanoparticles of other materials could be an interesting platform for various applications. We studied the encapsulation of nanoparticles into single-crystal ZnO nanorods by exploiting the crystal growth of ZnO in aqueous solution. Two types of nanodiamonds with mean diameters of 10 nm and 40 nm, respectively, and polymer nanobeads with size of 200 nm have been used to study the encapsulation process. It was found that by regrowing these ZnO nanorods with nanoparticles attached to their surfaces, a full encapsulation of nanoparticles into nanorods can be achieved. We demonstrate that our low-temperature aqueous solution growth of ZnO nanorods do not affect or cause degradation of the nanoparticles of either inorganic or organic materials. This new growth method opens the way to a plethora of applications combining the properties of single crystal host and encapsulated nanoparticles. We perform micro-photoluminescence measurement on a single ZnO nanorod containing luminescent nanodiamonds and the spectrum has a different shape from that of naked nanodiamonds, revealing the cavity effect of ZnO nanorod.

Probing defects in chemically synthesized ZnO nanostrucures by positron annihilation and photoluminescence spectroscopy

International Nuclear Information System (INIS)

Chaudhuri, S. K.; Das, D.; Ghosh, Manoranjan; Raychaudhuri, A. K.

2010-01-01

The present article describes the size induced changes in the structural arrangement of intrinsic defects present in chemically synthesized ZnO nanoparticles of various sizes. Routine x-ray diffraction and transmission electron microscopy have been performed to determine the shapes and sizes of the nanocrystalline ZnO samples. Detailed studies using positron annihilation spectroscopy reveals the presence of zinc vacancy. Whereas analysis of photoluminescence results predict the signature of charged oxygen vacancies. The size induced changes in positron parameters as well as the photoluminescence properties, has shown contrasting or nonmonotonous trends as size varies from 4 to 85 nm. Small spherical particles below a critical size (∼23 nm) receive more positive surface charge due to the higher occupancy of the doubly charge oxygen vacancy as compared to the bigger nanostructures where singly charged oxygen vacancy predominates. This electronic alteration has been seen to trigger yet another interesting phenomenon, described as positron confinement inside nanoparticles. Finally, based on all the results, a model of the structural arrangement of the intrinsic defects in the present samples has been reconciled.

Probing defects in chemically synthesized ZnO nanostrucures by positron annihilation and photoluminescence spectroscopy

Science.gov (United States)

Chaudhuri, S. K.; Ghosh, Manoranjan; Das, D.; Raychaudhuri, A. K.

2010-09-01

The present article describes the size induced changes in the structural arrangement of intrinsic defects present in chemically synthesized ZnO nanoparticles of various sizes. Routine x-ray diffraction and transmission electron microscopy have been performed to determine the shapes and sizes of the nanocrystalline ZnO samples. Detailed studies using positron annihilation spectroscopy reveals the presence of zinc vacancy. Whereas analysis of photoluminescence results predict the signature of charged oxygen vacancies. The size induced changes in positron parameters as well as the photoluminescence properties, has shown contrasting or nonmonotonous trends as size varies from 4 to 85 nm. Small spherical particles below a critical size (˜23 nm) receive more positive surface charge due to the higher occupancy of the doubly charge oxygen vacancy as compared to the bigger nanostructures where singly charged oxygen vacancy predominates. This electronic alteration has been seen to trigger yet another interesting phenomenon, described as positron confinement inside nanoparticles. Finally, based on all the results, a model of the structural arrangement of the intrinsic defects in the present samples has been reconciled.

Annealed Ce{sup 3+}-doped ZnO flower-like morphology synthesized by chemical bath deposition method

Energy Technology Data Exchange (ETDEWEB)

Koao, Lehlohonolo F., E-mail: koaolf@ufs.ac.za [Department of Physics, University of the Free State (Qwa Qwa campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Dejene, Francis B.; Tsega, Moges [Department of Physics, University of the Free State (Qwa Qwa campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Swart, Hendrik C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa)

2016-01-01

We have successfully synthesized ZnO:xmol% Ce{sup 3+} (0≤x≤10 mol%) doped nanopowders via the chemical bath deposition method (CBD) technique at low temperature (80 °C) and annealed in air at 700 °C. The X-ray diffraction patterns showed that all the undoped and Ce-doped ZnO nanopowders have a hexagonal wurtzite polycrystalline structure with an average crystallite size of about 46 nm. Weak diffraction peaks related mainly to cerium oxide were also detected at higher concentrations of Ce{sup 3+} (x=5–10 mol%). The scanning electron microscopy study revealed that the nanopowder samples were assembled in flower-shaped undoped ZnO and pyramid-shaped Ce{sup 3+}-doped ZnO nanostructures. The UV–vis spectra showed that the absorption edges shifted slightly to the longer wavelengths with the increase in the Ce{sup 3+} ions concentration. Moreover, the photoluminescence (PL) results showed a relative weak visible emission for the Ce{sup 3+}-doped ZnO nanoparticles compared to the undoped ZnO. The effects of Ce{sup 3+}-doping on the structure and PL of ZnO nanopowders are discussed in detail.

Biosynthesis and characterization of ZnO nanoparticles using the aqueous leaf extract of Imperata cylindrica L.

Science.gov (United States)

Saputra, I. S.; Yulizar, Y.

2017-04-01

ZnO nanoparticles (ZnO NPs) were biosynthesized.The growth was observed by a sol-gel method. ZnO were successfully formed through the reaction of zinc nitrate tetrahydrate Zn(NO3)2.4H2O precursor with aqueous leaf extract of Imperata cylindrica L (ICL). The structural and optical properties of ZnO were investigated. The as-synthesized products were characterized by UV-Visible (UV-Vis), UV diffuse reflectance spectroscopy (UV-DRS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). UV-Vis absorption data showed hydrolysis and characteristic of absorption peak at 300 nm of Zn(OH)2. UV-DRS confirmed that ZnO NPs has the indirect band gap at 3.13 eV. FTIR spectrum revealed the functional groups and indicated the presence of protein as the capping and stabilizing agent on the ZnO surface. Powder XRD studies indicated the formation of pure wurtzite hexagonal structure with particle size of 11.9 nm. The detailed morphological and structural characterizations revealed that the synthesized products were hexagonal nanochip.

High quantum yield ZnO quantum dots synthesizing via an ultrasonication microreactor method.

Science.gov (United States)

Yang, Weimin; Yang, Huafang; Ding, Wenhao; Zhang, Bing; Zhang, Le; Wang, Lixi; Yu, Mingxun; Zhang, Qitu

2016-11-01

Green emission ZnO quantum dots were synthesized by an ultrasonic microreactor. Ultrasonic radiation brought bubbles through ultrasonic cavitation. These bubbles built microreactor inside the microreactor. The photoluminescence properties of ZnO quantum dots synthesized with different flow rate, ultrasonic power and temperature were discussed. Flow rate, ultrasonic power and temperature would influence the type and quantity of defects in ZnO quantum dots. The sizes of ZnO quantum dots would be controlled by those conditions as well. Flow rate affected the reaction time. With the increasing of flow rate, the sizes of ZnO quantum dots decreased and the quantum yields first increased then decreased. Ultrasonic power changed the ultrasonic cavitation intensity, which affected the reaction energy and the separation of the solution. With the increasing of ultrasonic power, sizes of ZnO quantum dots first decreased then increased, while the quantum yields kept increasing. The effect of ultrasonic temperature on the photoluminescence properties of ZnO quantum dots was influenced by the flow rate. Different flow rate related to opposite changing trend. Moreover, the quantum yields of ZnO QDs synthesized by ultrasonic microreactor could reach 64.7%, which is higher than those synthesized only under ultrasonic radiation or only by microreactor. Copyright © 2016 Elsevier B.V. All rights reserved.

The crystallization and physical properties of Al-doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chen, K.J. [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Fang, T.H. [Institute of Mechanical and Electromechanical Engineering, National Formosa University, Yunlin 632, Taiwan (China); Hung, F.Y. [Institute of Nanotechnology and Microsystems Engineering, Center for Micro/Nano Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)], E-mail: fyhung@mail.mse.ncku.edu.tw; Ji, L.W. [Institute of Mechanical and Electromechanical Engineering, National Formosa University, Yunlin 632, Taiwan (China); Chang, S.J.; Young, S.J. [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Hsiao, Y.J. [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

2008-07-15

Un-doped Al (0-9 at.%) nanoparticles and doped ZnO powders were prepared by the sol-gel method. The nanoparticles were heated at 700-800 deg. C for 1 h in air and then analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra and photoluminescence (PL). The results of un-doped (ZnO) and Al-doped ZnO (AZO) nanoparticles were also compared to investigate the structural characteristics and physical properties. XRD patterns of AZO powders were similar to those of ZnO powders, indicating that micro-Al ions were substituted for Zn atoms and there were no variations in the structure of the ZnO nanoparticles. From the XRD and SEM data, the grain size of the AZO nanoparticles increased from 34.41 to 40.14 nm when the annealing temperature was increased. The Raman intensity of the AZO nanoparticles (Al = 5 at.%) increased when the annealing temperature was increased. Increasing the degree of crystalline not only reduced the residual stress, but also improved the physical properties of the nanoparticles.

The crystallization and physical properties of Al-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Chen, K.J.; Fang, T.H.; Hung, F.Y.; Ji, L.W.; Chang, S.J.; Young, S.J.; Hsiao, Y.J.

2008-01-01

Un-doped Al (0-9 at.%) nanoparticles and doped ZnO powders were prepared by the sol-gel method. The nanoparticles were heated at 700-800 deg. C for 1 h in air and then analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra and photoluminescence (PL). The results of un-doped (ZnO) and Al-doped ZnO (AZO) nanoparticles were also compared to investigate the structural characteristics and physical properties. XRD patterns of AZO powders were similar to those of ZnO powders, indicating that micro-Al ions were substituted for Zn atoms and there were no variations in the structure of the ZnO nanoparticles. From the XRD and SEM data, the grain size of the AZO nanoparticles increased from 34.41 to 40.14 nm when the annealing temperature was increased. The Raman intensity of the AZO nanoparticles (Al = 5 at.%) increased when the annealing temperature was increased. Increasing the degree of crystalline not only reduced the residual stress, but also improved the physical properties of the nanoparticles

Oxygen Vacancy-Mediated ZnO Nanoparticle Photocatalyst for Degradation of Methylene Blue

Directory of Open Access Journals (Sweden)

Qiuping Zhang

2018-02-01

Full Text Available ZnO nanoparticles (NPs are synthesized by deoxidizing ZnO powder in a vacuum drying process. This process reduces the size of the NPs and increases the concentration of oxygen vacancies on their surfaces. ZnO NPs with sufficient oxygen vacancies are highly effective for the photodecomposition of methylene blue (MB dye in water under ultraviolet irradiation. The MB degradation efficiency exceeds 99 percent after 50 min of light irradiation, and the catalytic property of the NPs remains stable over several complete degradation cycles. It is revealed that the concentration of oxygen vacancies on the surface, and the photocatalytic activity, are both higher for smaller NPs. Oxygen vacancies reduce the recombination rate of photo-generated charge carriers by capturing the electrons and hence, improve the efficiency of redox reactions. In addition, a smaller particle size leads to a larger specific surface area and a higher photonic efficiency for the ZnO NPs.

Spectroscopic characterization approach to study surfactants effect on ZnO 2 nanoparticles synthesis by laser ablation process

Science.gov (United States)

Drmosh, Q. A.; Gondal, M. A.; Yamani, Z. H.; Saleh, T. A.

2010-05-01

Zinc peroxide nanoparticles having grain size less than 5 nm were synthesized using pulsed laser ablation in aqueous solution in the presence of different surfactants and solid zinc target in 3% H 2O 2. The effect of surfactants on the optical and structure of ZnO 2 was studied by applying different spectroscopic techniques. Structural properties and grain size of the synthesized nanoparticles were studied using XRD method. The presence of the cubic phase of zinc peroxide in all samples was confirmed with XRD, and the grain sizes were 4.7, 3.7, 3.3 and 2.8 nm in pure H 2O 2, and H 2O 2 mixed with SDS, CTAB and OGM respectively. For optical characterization, FTIR transmittance spectra of ZnO 2 nanoparticles prepared with and without surfactants show a characteristic ZnO 2 absorption at 435-445 cm -1. FTIR spectrum revealed that the adsorbed surfactants on zinc peroxide disappeared in case of CTAB and OGM while it appears in case of SDS. This could be due to high critical micelles SDS concentration comparing with others which is attributed to the adsorption anionic nature of this surfactant. Both FTIR and UV-vis spectra show a red shift in the presence of SDS and blue shift in the presence of CTAB and OGM. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. The zinc peroxide nanoparticles prepared in additives-free media was also characterized by Raman spectra which show the characteristic peaks at 830-840 and 420-440 cm -1.

Spectroscopic characterization approach to study surfactants effect on ZnO2 nanoparticles synthesis by laser ablation process

International Nuclear Information System (INIS)

Drmosh, Q.A.; Gondal, M.A.; Yamani, Z.H.; Saleh, T.A.

2010-01-01

Zinc peroxide nanoparticles having grain size less than 5 nm were synthesized using pulsed laser ablation in aqueous solution in the presence of different surfactants and solid zinc target in 3% H 2 O 2 . The effect of surfactants on the optical and structure of ZnO 2 was studied by applying different spectroscopic techniques. Structural properties and grain size of the synthesized nanoparticles were studied using XRD method. The presence of the cubic phase of zinc peroxide in all samples was confirmed with XRD, and the grain sizes were 4.7, 3.7, 3.3 and 2.8 nm in pure H 2 O 2 , and H 2 O 2 mixed with SDS, CTAB and OGM respectively. For optical characterization, FTIR transmittance spectra of ZnO 2 nanoparticles prepared with and without surfactants show a characteristic ZnO 2 absorption at 435-445 cm -1 . FTIR spectrum revealed that the adsorbed surfactants on zinc peroxide disappeared in case of CTAB and OGM while it appears in case of SDS. This could be due to high critical micelles SDS concentration comparing with others which is attributed to the adsorption anionic nature of this surfactant. Both FTIR and UV-vis spectra show a red shift in the presence of SDS and blue shift in the presence of CTAB and OGM. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. The zinc peroxide nanoparticles prepared in additives-free media was also characterized by Raman spectra which show the characteristic peaks at 830-840 and 420-440 cm -1 .

Precipitated nickel doped ZnO nanoparticles with enhanced low temperature ethanol sensing properties

Directory of Open Access Journals (Sweden)

Umadevi Godavarti

2017-12-01

Full Text Available The Zn1-xNixO nanoparticles have been synthesized by novel co-precipitation method and systematically characterized by XRD, SEM, TEM and photo luminescence. The XRD patterns confirm the hexagonal wurzite structure without secondary phases in Ni substituted ZnO samples. SEM and TEM are used for the estimation of particle shape and size. In PL study there is a peak in the range of 380–390 nm in all samples that is attributed to the oxygen vacancies. Gas sensing tests reveal that Ni doped ZnO sensor has remarkably enhanced performance compared to pure ZnO detected at an optimum temperature 100 °C. It could detect ethanol gas in a wide concentration range with very high response, fast response–recovery time, good selectivity and stable repeatability. The possible sensing mechanism is discussed. The high response of ZnO Nanoparticles was attributed to large contacting surface area for electrons, oxygen, target gas molecule, and abundant channels for gas diffusion. The superior sensing features indicate the present Ni doped ZnO as a promising nanomaterial for gas sensors. The response time and recovery time of undoped is 75 s and 60 s and 0.25 at% Ni are found to be 60 s and 45 s at 100 °C respectively.

Size control synthesis and characterization of ZnO nanoparticles and its application as ZnO-water based nanofluid in heat transfer enhancement in light water nuclear reactor

Energy Technology Data Exchange (ETDEWEB)

Sharma, Deepak; Pandey, Krishna Murari [National Institute of Technology Silchar, Assam (India). Dept. of Mechanical Engineering

2017-03-15

A novel and facile approach for size-tunable synthesis of ZnO nanoparticle (NPs) is reported. Size-tuning was attained by using PEG (polyethylene glycol) of molecular weights 400 and 4000. ZnO NPs was synthesized using homogeneous chemical precipitation followed by hydrothermal. Here triethylamine (TEA) was used as a hydroxylating agent. As-synthesized ZnO NPs were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and Energy Dispersive Spectroscopy (EDS) analysis. Synthesized ZnO nanoparticle was used for the preparation of ZnO-water based nanofluid and its application in heat transfer enhancement in light water nuclear reactor. In this work, ZnO-water based nanofluid of different volume concentration (1%, 2% and 3%) and particle size of 10 nm and 20 nm is used for enhancement in heat transfer in annular channel by using two phase approach. The particle size of 10 nm gives better result for enhancing the heat transfer rate in comparison to 20 nm particle size in nuclear reactor.

Photoreactivity of ZnO nanoparticles in visible light: Effect of surface states on electron transfer reaction

International Nuclear Information System (INIS)

Baruah, Sunandan; Dutta, Joydeep; Sinha, Sudarson Sekhar; Ghosh, Barnali; Pal, Samir Kumar; Raychaudhuri, A. K.

2009-01-01

Wide band gap metal oxide semiconductors such as zinc oxide (ZnO) show visible band photolysis that has been employed, among others, to degrade harmful organic contaminants into harmless mineral acids. Metal oxides show enhanced photocatalytic activity with the increase in electronic defects in the crystallites. By introducing defects into the crystal lattice of ZnO nanoparticles, we observe a redshift in the optical absorption shifting from the ultraviolet region to the visible region (400-700 nm), which is due to the creation of intermediate defect states that inhibit the electron hole recombination process. The defects were introduced by fast nucleation and growth of the nanoparticles by rapid heating using microwave irradiation and subsequent quenching during the precipitation reaction. To elucidate the nature of the photodegradation process, picosecond resolved time correlated single photon count (TCSPC) spectroscopy was carried out to record the electronic transitions resulting from the de-excitation of the electrons to their stable states. Photodegradation and TCSPC studies showed that defect engineered ZnO nanoparticles obtained through fast crystallization during growth lead to a faster initial degradation rate of methylene blue as compared to the conventionally synthesized nanoparticles

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

Directory of Open Access Journals (Sweden)

Jinzhang Liu

2014-04-01

Full Text Available One-dimensional single crystal incorporating functional nanoparticles of other materials could be an interesting platform for various applications. We studied the encapsulation of nanoparticles into single-crystal ZnO nanorods by exploiting the crystal growth of ZnO in aqueous solution. Two types of nanodiamonds with mean diameters of 10 nm and 40 nm, respectively, and polymer nanobeads with size of 200 nm have been used to study the encapsulation process. It was found that by regrowing these ZnO nanorods with nanoparticles attached to their surfaces, a full encapsulation of nanoparticles into nanorods can be achieved. We demonstrate that our low-temperature aqueous solution growth of ZnO nanorods do not affect or cause degradation of the nanoparticles of either inorganic or organic materials. This new growth method opens the way to a plethora of applications combining the properties of single crystal host and encapsulated nanoparticles. We perform micro-photoluminescence measurement on a single ZnO nanorod containing luminescent nanodiamonds and the spectrum has a different shape from that of naked nanodiamonds, revealing the cavity effect of ZnO nanorod.

Surface nanostructuring of thin film composite membranes via grafting polymerization and incorporation of ZnO nanoparticles

Science.gov (United States)

Isawi, Heba; El-Sayed, Magdi H.; Feng, Xianshe; Shawky, Hosam; Abdel Mottaleb, Mohamed S.

2016-11-01

A new approach for modification of polyamid thin film composite membrane PA(TFC) using synthesized ZnO nanoparticles (ZnO NPs) was shown to enhance the membrane performances for reverse osmosis water desalination. First, active layer of synthesis PA(TFC) membrane was activated with an aqueous solution of free radical graft polymerization of hydrophilic methacrylic acid (MAA) monomer onto the surface of the PA(TFC) membrane resulting PMAA-g-PA(TFC). Second, the PA(TFC) membrane has been developed by incorporation of ZnO NPs into the MAA grafting solution resulting the ZnO NPs modified PMAA-g-PA(TFC) membrane. The surface properties of the synthesized nanoparticles and prepared membranes were investigated using the FTIR, XRD and SEM. Morphology studies demonstrated that ZnO NPs have been successfully incorporated into the active grafting layer over PA(TFC) composite membranes. The zinc leaching from the ZnO NPs modified PMAA-g-PA(TFC) was minimal, as shown by batch tests that indicated stabilization of the ZnO NPs on the membrane surfaces. Compared with the a pure PA(TFC) and PMAA-g-PA(TFC) membranes, the ZnO NPs modified PMAA-g-PA(TFC) was more hydrophilic, with an improved water contact angle (∼50 ± 3°) over the PMAA-g-PA(TFC) (63 ± 2.5°). The ZnO NPs modified PMAA-g-PA(TFC) membrane showed salt rejection of 97% (of the total groundwater salinity), 99% of dissolved bivalent ions (Ca2+, SO42-and Mg2+), and 98% of mono valent ions constituents (Cl- and Na+). In addition, antifouling performance of the membranes was determined using E. coli as a potential foulant. This demonstrates that the ZnO NPs modified PMAA-g-PA(TFC) membrane can significantly improve the membrane performances and was favorable to enhance the selectivity, permeability, water flux, mechanical properties and the bio-antifouling properties of the membranes for water desalination.

Biological synthesis of ZnO nanoparticles using C. albicans and studying their catalytic performance in the synthesis of steroidal pyrazolines

Directory of Open Access Journals (Sweden)

Shamsuzzaman

2017-05-01

Full Text Available In this study, we describe a green and simple procedure for biosynthesis of ZnO nanoparticles using Candida albicans as eco-friendly reducing and capping agent. The synthesized ZnO nanoparticles were characterized by UV–vis spectroscopy, powder X-ray diffraction, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL, thermo gravimetric analysis (TGA and differential thermal analysis (DTA. The prepared nano-particles were used as catalyst for the fast and efficient synthesis of steroidal pyrazolines (4–9 from α, β-unsaturated steroidal ketones (1–3. The target molecules were obtained in good to excellent yields applying the current method.

Reducing ZnO nanoparticle cytotoxicity by surface modification.

Science.gov (United States)

Luo, Mingdeng; Shen, Cenchao; Feltis, Bryce N; Martin, Lisandra L; Hughes, Anthony E; Wright, Paul F A; Turney, Terence W

2014-06-07

Nanoparticulate zinc oxide (ZnO) is one of the most widely used engineered nanomaterials and its toxicology has gained considerable recent attention. A key aspect for controlling biological interactions at the nanoscale is understanding the relevant nanoparticle surface chemistry. In this study, we have determined the disposition of ZnO nanoparticles within human immune cells by measurement of total Zn, as well as the proportions of extra- and intracellular dissolved Zn as a function of dose and surface coating. From this mass balance, the intracellular soluble Zn levels showed little difference in regard to dose above a certain minimal level or to different surface coatings. PEGylation of ZnO NPs reduced their cytotoxicity as a result of decreased cellular uptake arising from a minimal protein corona. We conclude that the key role of the surface properties of ZnO NPs in controlling cytotoxicity is to regulate cellular nanoparticle uptake rather than altering either intracellular or extracellular Zn dissolution.

The Fate of ZnO Nanoparticles Administered to Human Bronchial Epithelial Cells

Science.gov (United States)

Gilbert, Benjamin; Fakra, Sirine C.; Xia, Tian; Pokhrel, Suman; Mädler, Lutz; Nel, André E.

2014-01-01

A particular challenge for nanotoxicology is the evaluation of the biological fate and toxicity of nanomaterials that dissolve in aqueous fluids. Zinc oxide nanomaterials are of particular concern because dissolution leads to release of the toxic divalent zinc ion. Although dissolved zinc ions have been implicated in ZnO cytotoxicity, direct identification of the chemical form of zinc taken up by cells exposed to ZnO nanoparticles, and its intracellular fate, has not yet been achieved. We combined high resolution X-ray spectromicroscopy and high elemental sensitivity X-ray microprobe analyses to determine the fate of ZnO and less soluble iron-doped ZnO nanoparticles following exposure to cultures of human bronchial epithelial cells, BEAS-2B. We complemented two-dimensional X-ray imaging methods with atomic force microscopy of cell surfaces to distinguish between nanoparticles that were transported inside the cells from those that adhered to the cell exterior. The data suggest cellular uptake of ZnO nanoparticles is a mechanism of zinc accumulation in cells. Following uptake, ZnO nanoparticles dissolved completely generating intracellular Zn2+ complexed by molecular ligands. These results corroborate a model for ZnO nanoparticle toxicity that is based on nanoparticle uptake followed by intracellular dissolution. PMID:22646753

ZnO nanostructure fabrication in different solvents transforms physio-chemical, biological and photodegradable properties

Energy Technology Data Exchange (ETDEWEB)

Ali, Attarad; Ambreen, Sidra; Javed, Rabia; Tabassum, Saira [Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ul Haq, Ihsan [Department of Pharmacy, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Zia, Muhammad, E-mail: ziachaudhary@gmail.com [Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2017-05-01

Zinc oxide (ZnO) nanostructures are synthesized in various organic solvents (acetone, chloroform, ethyl acetate, ethanol and methanol) and water via coprecipitation process using zinc acetate as precursor. The resultant ZnO nanoparticles, nano rods and nano sheets are characterized by UV–vis spectrophotometric analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). The variable size and geometry of nanoparticles depend upon medium used for synthesis. The synthesized ZnO nanostructures exhibit minor to moderate antioxidative (DPPH based free radical scavenging activity, total antioxidative potential and total reducing power) response. Mild to moderate antibacterial and antifungal activities, excellent antileishmanial potential (IC50 up to 3.76), and good cytotoxic perspective (LD50 up to 49.4) is also observed by the synthesized ZnO NPs. The nanoparticles also exhibit moderate α-amylase inhibition response. Furthermore the nanostructures are evaluated for methylene blue photodegradation response within 60 min time period. It is found that organic solvent alters shape, size and other physio-chemical properties of ZnO that ultimately modulate the biological, chemical, and environmental properties. - Highlights: • Zinc oxide nanoparticles are fabricated in different solvents using co-precipitation method • SEM, XRD and FTIR analysis confirms variation in physical and chemical characteristics of synthesized ZnO NPs • The synthesized ZnO demonstrates variation in biological, phytochemical and photodegradable properties.

ZnO nanostructure fabrication in different solvents transforms physio-chemical, biological and photodegradable properties

International Nuclear Information System (INIS)

Ali, Attarad; Ambreen, Sidra; Javed, Rabia; Tabassum, Saira; Ul Haq, Ihsan; Zia, Muhammad

2017-01-01

Zinc oxide (ZnO) nanostructures are synthesized in various organic solvents (acetone, chloroform, ethyl acetate, ethanol and methanol) and water via coprecipitation process using zinc acetate as precursor. The resultant ZnO nanoparticles, nano rods and nano sheets are characterized by UV–vis spectrophotometric analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). The variable size and geometry of nanoparticles depend upon medium used for synthesis. The synthesized ZnO nanostructures exhibit minor to moderate antioxidative (DPPH based free radical scavenging activity, total antioxidative potential and total reducing power) response. Mild to moderate antibacterial and antifungal activities, excellent antileishmanial potential (IC50 up to 3.76), and good cytotoxic perspective (LD50 up to 49.4) is also observed by the synthesized ZnO NPs. The nanoparticles also exhibit moderate α-amylase inhibition response. Furthermore the nanostructures are evaluated for methylene blue photodegradation response within 60 min time period. It is found that organic solvent alters shape, size and other physio-chemical properties of ZnO that ultimately modulate the biological, chemical, and environmental properties. - Highlights: • Zinc oxide nanoparticles are fabricated in different solvents using co-precipitation method • SEM, XRD and FTIR analysis confirms variation in physical and chemical characteristics of synthesized ZnO NPs • The synthesized ZnO demonstrates variation in biological, phytochemical and photodegradable properties.

Photoluminescence quenching and enhanced spin relaxation in Fe doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ovhal, Manoj M.; Santhosh Kumar, A. [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India); Khullar, Prerna [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Kumar, Manjeet [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India); Abhyankar, A.C., E-mail: ashutoshabhyankar@gmail.com [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India)

2017-07-01

Cost-effective ultrasonically assisted precipitation method is utilized to synthesize Zinc oxide (ZnO) nanoparticles (NPs) at room temperature and the effect of Iron (Fe) doping on structural, optical and spin relaxation properties also presented. As-synthesized pure and Fe doped ZnO NPs possess a perfect hexagonal growth habit of wurtzite zinc oxide, along the (101) direction of preference. With Fe doping, ‘c/a’ ratio and compressive lattice strain in ZnO NPs are found to reduce and increase, respectively. Raman studies demonstrate that the E{sub 1} longitudinal optical (LO) vibrational mode is very weak in pure which remarkably enhanced with Fe doping into ZnO NPs. The direct band gap energy (E{sub g}) of the ZnO NPs has been increased from 3.02 eV to 3.11 eV with Fe doping. A slight red-shift observed with strong green emission band, in photoluminescence spectra, is strongly quenched in 6 wt.% Fe doped ZnO NPs. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) reveals spherical shape of ZnO NPs with 60–70 nm, which reduces substantially on Fe doping. The energy dispersive X-ray spectrum and elemental mapping confirms the homogeneous distribution of Fe in ZnO NPs. Moreover, the specific relaxation rate (R{sub 2sp} = 1/T{sub 2}) has been measured using Carr-Purcell-Meiboom-Gill (CPMG) method and found to be maximum in 6 wt.% Fe doped ZnO NPs. Further, the correlation of structural, optical and dynamic properties is proposed. - Highlights: • Pure ZnO and Fe doped ZnO NPs were successfully prepared by cost effective ultrasonically assisted precipitation method. • The optical band gap of ZnO has been enhanced form 3.02–3.11 eV with Fe doping. • PL quenching behaviour has been observed with Fe{sup 3+} ions substitution in ZnO lattice. • Specific relaxation rate (R{sub 2sp} = 1/T{sub 2}) has been varied with Fe doping and found to be maximum in 6 wt.% Fe doped ZnO NPs.

Strong blue emission from ZnO nanocrystals synthesized in acetone-based solvent

International Nuclear Information System (INIS)

Efafi, B.; Majles Ara, M.H.; Mousavi, S.S.

2016-01-01

In this research, ZnO nanocrystals were synthesized by an improved sol–gel method. UV–vis, FTIR and photoluminescence spectra of the ZnO solution synthesized by this route indicated different properties compared to the other preparation methods. It was observed from FTIR that the sol (prepared using acetone) with the low concentration contains a noticeable amount of the Zn–O bond. The PL spectrum with a strong blue emission confirmed that these nanocrystals are good candidate for use in applications where a monochromatic emission is required. To the best of our knowledge, monochromatic emission ZnO devices have been fabricated through high technology instruments but this paper introduces a simple method for preparation of ZnO with the high intensity blue peak. The size and morphology of ZnO nanocrystals have been studied using FESEM. The nanocrystal size was estimated about 70 nm which was in good agreement with XRD data. - Highlights: • Preparation of ZnO nanocrystals through a novel method by the use of acetone as the solvent. • Observation of the strong blue emission peak from the ZnO prepared solution. • Reduction of green emission in the synthesized sample compared to the other methods of preparation.

Strong blue emission from ZnO nanocrystals synthesized in acetone-based solvent

Energy Technology Data Exchange (ETDEWEB)

Efafi, B. [NanoPhotonics Lab., Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of); Departments of Physics, Iran University of Science & Technology, Tehran (Iran, Islamic Republic of); Majles Ara, M.H., E-mail: majlesara@gmail.com [NanoPhotonics Lab., Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of); Mousavi, S.S. [NanoPhotonics Lab., Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of)

2016-10-15

In this research, ZnO nanocrystals were synthesized by an improved sol–gel method. UV–vis, FTIR and photoluminescence spectra of the ZnO solution synthesized by this route indicated different properties compared to the other preparation methods. It was observed from FTIR that the sol (prepared using acetone) with the low concentration contains a noticeable amount of the Zn–O bond. The PL spectrum with a strong blue emission confirmed that these nanocrystals are good candidate for use in applications where a monochromatic emission is required. To the best of our knowledge, monochromatic emission ZnO devices have been fabricated through high technology instruments but this paper introduces a simple method for preparation of ZnO with the high intensity blue peak. The size and morphology of ZnO nanocrystals have been studied using FESEM. The nanocrystal size was estimated about 70 nm which was in good agreement with XRD data. - Highlights: • Preparation of ZnO nanocrystals through a novel method by the use of acetone as the solvent. • Observation of the strong blue emission peak from the ZnO prepared solution. • Reduction of green emission in the synthesized sample compared to the other methods of preparation.

Synthesis and Characterization of Nanoparticles and Nanocomposite of ZnO and MgO by Sonochemical Method and their Application for Zinc Polycarboxylate Dental Cement Preparation

OpenAIRE

Mohammad Ali Karimi; Saeed Haghdar Roozbahani; Reza Asadiniya; Abdolhamid Hatefi-Mehrjardi; Mohammad Hossein Mashhadizadeh; Reza Behjatmanesh-Ardakani; Mohammad Mazloum-Ardakani; Hadi Kargar; Seyed Mojtaba Zebarjad

2011-01-01

This paper discusses the synthesis of nanoparticles of ZnO and MgO and ZnO/MgO nanocomposite by the sonochemical method. At first, nanoparticles were synthesized by the reaction of Zn(CHCOO3)2 and Mg(CHCOO3)2 with tetramethylammonium hydroxide (TMAH) in the presence of polyvinyl pyrrolidone (PVP) and constant frequency ultrasonic waves (sonochemical method). Then, ZnO/MgO nanocomposite was prepared through reaction of magnesium acetate with TMAH in the presence of ZnO nanoparticles and PVP as...

Investigating the Implementation of ZnO Nanoparticles as a Tunable UV Detector for Different Skin Types

Science.gov (United States)

Mosayebi, Pegah; Dorranian, Davoud; Behzad, Kasra

A facile chemical reduction method was used to synthesize ZnO nanoparticles (NPs) in ethylene glycol solvent at two different calcination temperatures. As a result of variation in the calcination temperature, ZnO NPs with two different sizes were achieved. The NPs were investigated for their structural and optical characteristics using X-ray diffraction and ultraviolet (UV)-Vis spectroscopy. The synthesized ZnO NPs exhibited a hexagonal structure with sizes of 46 and 65nm. The synthesized NPs were then used to investigate dye photocatalytic behavior of products as a tunable UV detector for different skin types. The dye degradation and decolorization of methylene blue in the presence of ZnO NP, following UV radiation as a function of time, were studied at different pH levels. The optical absorption spectra were then taken every 15min for all samples. The UV-Vis spectroscopy spectra revealed that optical absorption of solution was decreased upon UV exposure as a function of time. Photocatalytic reaction indicated that the dye degradation and decolorization rate were accelerated with the increase of pH level. Therefore, a tunable UV detector for different skin types could be engineered by varying the pH level of solution to avoid human skin burning.

Structure and morphologies of ZnO nanoparticles synthesized by pulsed laser ablation in liquid: Effects of temperature and energy fluence

Energy Technology Data Exchange (ETDEWEB)

Guillén, G. García; Palma, M.I. Mendivil [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); Krishnan, B. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); Universidad Autónoma de Nuevo León – Centro de Innovación, Investigación y Desarrollo de Ingeniería y Tecnología, Apodaca, Nuevo León 66600 (Mexico); Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66455 (Mexico); and others

2015-07-15

Zinc oxide nanoparticles were prepared by pulsed laser ablation of a zinc metal target at different water temperatures (room temperature, 50, 70 and 90 °C). Ablation was carried out using 532 nm output from a pulsed (10 ns, 10 Hz) Nd:YAG laser at three different laser fluence. Analysis of the morphology, crystalline phase, elemental composition, optical and luminescent properties were done using Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS), UV–visible absorption spectroscopy and photoluminescence spectroscopy. TEM analysis showed that a change in temperature resulted in ZnO and Zn(OH){sub 2} nanoparticles with different sizes and morphologies. XPS results confirmed the compositions and chemical states of these nanoparticles. These zinc nanomaterials showed emission in the ultraviolet (UV) and blue regions. The results of this work demonstrated that by varying the liquid medium temperature, the structure, composition, morphology and optical properties of the nanomaterials could be modified during pulsed laser ablation in liquid. - Graphical abstract: Display Omitted - Highlights: • Zinc nanomaterial colloids were synthesized by PLAL. • Effects of laser fluence and the distilled water temperature were analyzed. • The final structure varied with the distilled water temperature and laser fluence. • The morphology was dependent on the distilled water temperature and laser fluence. • Zinc nanocolloids showed emission in the UV and blue region.

Structure and morphologies of ZnO nanoparticles synthesized by pulsed laser ablation in liquid: Effects of temperature and energy fluence

International Nuclear Information System (INIS)

Guillén, G. García; Palma, M.I. Mendivil; Krishnan, B.; Avellaneda, D.; Castillo, G.A.; Roy, T.K. Das

2015-01-01

Zinc oxide nanoparticles were prepared by pulsed laser ablation of a zinc metal target at different water temperatures (room temperature, 50, 70 and 90 °C). Ablation was carried out using 532 nm output from a pulsed (10 ns, 10 Hz) Nd:YAG laser at three different laser fluence. Analysis of the morphology, crystalline phase, elemental composition, optical and luminescent properties were done using Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS), UV–visible absorption spectroscopy and photoluminescence spectroscopy. TEM analysis showed that a change in temperature resulted in ZnO and Zn(OH) 2 nanoparticles with different sizes and morphologies. XPS results confirmed the compositions and chemical states of these nanoparticles. These zinc nanomaterials showed emission in the ultraviolet (UV) and blue regions. The results of this work demonstrated that by varying the liquid medium temperature, the structure, composition, morphology and optical properties of the nanomaterials could be modified during pulsed laser ablation in liquid. - Graphical abstract: Display Omitted - Highlights: • Zinc nanomaterial colloids were synthesized by PLAL. • Effects of laser fluence and the distilled water temperature were analyzed. • The final structure varied with the distilled water temperature and laser fluence. • The morphology was dependent on the distilled water temperature and laser fluence. • Zinc nanocolloids showed emission in the UV and blue region

Can visible light impact litter decomposition under pollution of ZnO nanoparticles?

Science.gov (United States)

Du, Jingjing; Zhang, Yuyan; Liu, Lina; Qv, Mingxiang; Lv, Yanna; Yin, Yifei; Zhou, Yinfei; Cui, Minghui; Zhu, Yanfeng; Zhang, Hongzhong

2017-11-01

ZnO nanoparticles is one of the most used materials in a wide range including antibacterial coating, electronic device, and personal care products. With the development of nanotechnology, ecotoxicology of ZnO nanoparticles has been received increasing attention. To assess the phototoxicity of ZnO nanoparticles in aquatic ecosystem, microcosm experiments were conducted on Populus nigra L. leaf litter decomposition under combined effect of ZnO nanoparticles and visible light radiation. Litter decomposition rate, pH value, extracellular enzyme activity, as well as the relative contributions of fungal community to litter decomposition were studied. Results showed that long-term exposure to ZnO nanoparticles and visible light led to a significant decrease in litter decomposition rate (0.26 m -1 vs 0.45 m -1 ), and visible light would increase the inhibitory effect (0.24 m -1 ), which caused significant decrease in pH value of litter cultures, fungal sporulation rate, as well as most extracellular enzyme activities. The phototoxicity of ZnO nanoparticles also showed impacts on fungal community composition, especially on the genus of Varicosporium, whose abundance was significantly and positively related to decomposition rate. In conclusion, our study provides the evidence for negatively effects of ZnO NPs photocatalysis on ecological process of litter decomposition and highlights the contribution of visible light radiation to nanoparticles toxicity in freshwater ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of the Absorption Behaviour of ZnO Nanoparticles on Cytotoxicity Measurements

Directory of Open Access Journals (Sweden)

Nigar Najim

2014-01-01

Full Text Available ZnO absorbs certain wavelengths of light and this behavior is more pronounced for nanoparticles of ZnO. As many toxicity measurements rely on measuring light transmission in cell lines, it is essential to determine how far this light absorption influences experimental toxicity measurements. The main objective was to study the ZnO absorption and how this influenced the cytotoxicity measurements. The cytotoxicity of differently sized ZnO nanoparticles in normal and cancer cell lines derived from lung tissue (Hs888Lu, neuron-phenotypic cells (SH-SY5Y, neuroblastoma (SH-SY5Y, human histiocytic lymphoma (U937, and lung cancer (A549 was investigated. Our results demonstrate that the presence of ZnO affected the cytotoxicity measurements due to the absorption characteristic of ZnO nanoparticles. The data revealed that the ZnO nanoparticles with an average particle size of around 85.7 nm and 190 nm showed cytotoxicity towards U937, SH-SY5Y, differentiated SH-SY5Y, and Hs888Lu cell lines. No effect on the A549 cells was observed. It was also found that the cytotoxicity of ZnO was particle size, concentration, and time dependent. These studies are the first to quantify the influence of ZnO nanoparticles on cytotoxicity assays. Corrections for absorption effects were carried out which gave an accurate estimation of the concentrations that produce the cytotoxic effects.

Ultraviolet photosensors fabricated with Ag nanowires coated with ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Shen, Guan-Hung [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Hong, Franklin Chau-Nan, E-mail: hong@mail.ncku.edu.tw [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan (China); NCKU Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 70101, Taiwan (China)

2014-11-03

We have developed a simple low temperature process to coat zinc oxide (ZnO) nanoparticles (NPs) on Ag nanowires (NWs) with well-controlled morphology. Triethanolamine (TEA) was employed to react with zinc acetate (Zn(CH{sub 3}COO){sub 2}) forming ZnO NPs. TEA was also found to enhance the nucleation and binding of ZnO NPs on the Ag nanowire surfaces facilitating a complete coverage of Ag nanowire surfaces with ZnO NPs. The effects of the process parameters including reaction time and reaction temperature were studied. The surfaces of 60 nm diameter Ag NWs could be completely covered with ZnO NPs with the final diameters of Ag-NWs@ZnO (core–shell NWs) turning into the range from 100 nm to 450 nm. The Ag-NWs@ZnO was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray mapping analysis, X-ray diffraction, and photoluminescence spectra. Finally, ultraviolet (UV) photosensors were fabricated using Ag-NWs@ZnO. They were found to improve photosensitivity with greatly enhanced fast response by reducing the recovery time by 2 orders, in comparison with the UV-sensors using single-crystalline ZnO NWs. - Highlights: • Solution process to coat ZnO nanoparticles on Ag nanowires has been developed. • Ultraviolet photosensing of ZnO nanoparticles coated on the Ag nanowires was found. • High defect concentration of ZnO nanoparticles enhanced the photosensing properties.

Structural interpretation of chemically synthesized ZnO nanorod and its application in lithium ion battery

International Nuclear Information System (INIS)

Kundu, Samapti; Sain, Sumanta; Yoshio, Masaki; Kar, Tanusree; Gunawardhana, Nanda; Pradhan, Swapan Kumar

2015-01-01

Graphical abstract: - Highlights: • ZnO nanorods are synthesized at room temperature via a simple chemical route. • Growth direction of ZnO nanorods has been determined along 〈0 0 2〉. • ZnO nanorods constructed anode shows a high discharge capacity in first cycle. • It retains good reversible capacity compared to other ZnO morphologies. - Abstract: ZnO nanorods are synthesized at room temperature via a simple chemical route without using any template or capping agent and its importance is evaluated as a suitable candidate for anode material in lithium ion battery. Structural and microstructure characterizations of these nanorods are made by analyzing the X-ray diffraction data employing the Rietveld method of powder structure refinement. It reveals that the ZnO nanorods are grown up with a preferred orientation and elongated along 〈0 0 2〉. FESEM images reveal that these uniform cylindrical shaped nanorods are of different lengths and diameters. These synthesized ZnO nanorods are tested as an anode material for lithium ion batteries. The nano grain size of the ZnO rods results in less volume expansion and/or contraction during the alloying/de-alloying process and causes in good cyclability. In addition, synthesized ZnO nanorods deliver high charge/discharge capacities compared to other reported ZnO materials

Structural interpretation of chemically synthesized ZnO nanorod and its application in lithium ion battery

Energy Technology Data Exchange (ETDEWEB)

Kundu, Samapti; Sain, Sumanta [Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India); Yoshio, Masaki [Advanced Research and Education Centre, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan); Kar, Tanusree [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, West Bengal (India); Gunawardhana, Nanda, E-mail: nandagunawardhana@pdn.ac.lk [International Research Centre, Senate Building, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Pradhan, Swapan Kumar, E-mail: skpradhan@phys.buruniv.ac.in [Materials Science Division, Department of Physics, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)

2015-02-28

Graphical abstract: - Highlights: • ZnO nanorods are synthesized at room temperature via a simple chemical route. • Growth direction of ZnO nanorods has been determined along 〈0 0 2〉. • ZnO nanorods constructed anode shows a high discharge capacity in first cycle. • It retains good reversible capacity compared to other ZnO morphologies. - Abstract: ZnO nanorods are synthesized at room temperature via a simple chemical route without using any template or capping agent and its importance is evaluated as a suitable candidate for anode material in lithium ion battery. Structural and microstructure characterizations of these nanorods are made by analyzing the X-ray diffraction data employing the Rietveld method of powder structure refinement. It reveals that the ZnO nanorods are grown up with a preferred orientation and elongated along 〈0 0 2〉. FESEM images reveal that these uniform cylindrical shaped nanorods are of different lengths and diameters. These synthesized ZnO nanorods are tested as an anode material for lithium ion batteries. The nano grain size of the ZnO rods results in less volume expansion and/or contraction during the alloying/de-alloying process and causes in good cyclability. In addition, synthesized ZnO nanorods deliver high charge/discharge capacities compared to other reported ZnO materials.

Halloysite Nanotubes Supported Ag and ZnO Nanoparticles with Synergistically Enhanced Antibacterial Activity

Science.gov (United States)

Shu, Zhan; Zhang, Yi; Yang, Qian; Yang, Huaming

2017-02-01

Novel antimicrobial nanocomposite incorporating halloysite nanotubes (HNTs) and silver (Ag) into zinc oxide (ZnO) nanoparticles is prepared by integrating HNTs and decorating Ag nanoparticles. ZnO nanoparticles (ZnO NPs) and Ag nanoparticles (Ag NPs) with a size of about 100 and 8 nm, respectively, are dispersively anchored onto HNTs. The synergistic effects of ZnO NPs, Ag NPs, and HNTs led to the superior antibacterial activity of the Ag-ZnO/HNTs antibacterial nanocomposites. HNTs facilitated the dispersion and stability of ZnO NPs and brought them in close contact with bacteria, while Ag NPs could promote the separation of photogenerated electron-hole pairs and enhanced the antibacterial activity of ZnO NPs. The close contact with cell membrane enabled the nanoparticles to produce the increased concentration of reactive oxygen species and the metal ions to permeate into the cytoplasm, thus induced quick death of bacteria, indicating that Ag-ZnO/HNTs antibacterial nanocomposite is a promising candidate in the antibacterial fields.

Synthesis of Cu and Ce co-doped ZnO nanoparticles: crystallographic, optical, molecular, morphological and magnetic studies

Directory of Open Access Journals (Sweden)

Rawat Mohit

2017-07-01

Full Text Available In the present research work, crystallographic, optical, molecular, morphological and magnetic properties of Zn1-xCuxO (ZnCu and Zn1-x-yCeyCuxO (ZnCeCu nanoparticles have been investigated. Polyvinyl alcohol (PVA coated ZnCu and ZnCeCu nanoparticles have been synthesized by chemical sol-gel method and thoroughly studied using various characterization techniques. X-ray diffraction pattern indicates the wurtzite structure of the synthesized ZnCu and ZnCeCu particles. Transmission electron microscopy analysis shows that the synthesized ZnCu and ZnCeCu particles are of spherical shape, having average sizes of 27 nm and 23 nm, respectively. The incorporation of Cu and Ce in the ZnO lattice has been confirmed through Fourier transform infrared spectroscopy. Room temperature photoluminescence spectra of the ZnO doped with Cu and co-doped Ce display two emission bands, predominant ultra-violet near-band edge emission at 409.9 nm (3 eV and a weak green-yellow emission at 432.65 nm (2.27 eV. Room temperature magnetic study confirms the diamagnetic behavior of ZnCu and ferromagnetic behavior of ZnCeCu.

Structural, optical, thermal and Photocatalytic properties of ZnO nanoparticles of Betel Leave by using Green synthesis method

Directory of Open Access Journals (Sweden)

S. Rajesh

2016-07-01

Full Text Available In this present study reports the green synthesis of zinc oxide nanoparticles using Betel leaf extracts and zinc acetate. The functionalization of ZnO particles through Betel leaf extract mediated bio reduction of ZnO was investigated through X-ray diffraction, Field emission scanning electron microscopy, photoluminescence, thermal gravimetric-differential thermal analysis, hexagonal shaped ZnO-nanoparticles  with  size  about  50 nm  were synthesized and characterized using X-ray diffraction analysis. The diameter of the nanoparticles in the range of 50 nm was found from scanning electron microscopy study. Photo luminescence study reveals the blue emission at 463nm respectively. hermal gravimetric-differential thermal analysis show that the observed at 480oC, indicating that no decomposition occurs above this temperature. The photocatalytic degradation of methylene blue dye was examined using ZnO nanoparticles under solar as well as ultra violet light irradiation of the MB dye. The  method  stands out primarily due to the fact that it is eco-friendly and shuts down the demerits of conventional  physical  and  chemical  methods. These particles are anticipated to have extensive applications in various industries.

Enhanced optical and electrical properties of Y-doped ZnO nanoparticles having different Y concentrations

Science.gov (United States)

Üzar, Neslihan

2018-04-01

In this study, undoped ZnO and yttrium (Y)-doped ZnO (YZO) nanoparticles having different Y dopant concentrations (Zn1- x Y x O; x = 0.005, 0.01, 0.015, 0.02) were successfully synthesized by sol-gel dip-coating method. Structural characterizations of the obtained samples were examined with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses. SEM analysis shows that the synthesized nanoparticles are mostly dot-like structures. The sizes of nanostructures decrease with increasing Y-doping concentration up to 2 mol % Y and XRD results show that all of samples have wurtzite hexagonal structure of ZnO with (002) c-plane orientation. According to EDS results pure YZO samples are obtained. Optical transmittances of all samples were investigated in the range of 350-750 nm at room temperature. The average optical transmittances of YZO samples in the visible region are approximately over 90%, but the transmittance starts to decrease for Zn0.98Y0.02O sample. Also, it was observed that the optical transmittances of Y-doped samples are higher than that of undoped ZnO. The electrical properties of YZO samples were obtained by resistance measurements at room temperature. The resistivity of samples was found to be 2.25 × 10-3, 1.43 × 10-3, 7.8 × 10-3, and 1.3 × 10-3 Ω-cm for Zn0.995Y0.005O, Zn0.99Y0.01O, Zn0.985Y0.015O and Zn0.98Y0.02O, respectively. All these results show that surface, structural, electrical and optical properties of ZnO samples can be improved with doping Y up to 2 mol % concentrations.

Vegetable Peel Waste for the Production of ZnO Nanoparticles and its Toxicological Efficiency, Antifungal, Hemolytic, and Antibacterial Activities

Science.gov (United States)

Surendra, T. V.; Roopan, Selvaraj Mohana; Al-Dhabi, Naif Abdullah; Arasu, Mariadhas Valan; Sarkar, Gargi; Suthindhiran, K.

2016-12-01

Zinc oxide (ZnO) nanoparticles (NPs) are important materials when making different products like sun screens, textiles, and paints. In the current study, the photocatalytic effect of prepared ZnO NPs from Moringa oleifera ( M. oleifera) was evaluated on degradation of crystal violet (CV) dye, which is largely released from textile industries and is harmful to the environment. Preliminarily, ZnO NP formation was confirmed using a double beam ultraviolet visible (UV-Vis) spectrophotometer; further, the NP size was estimated using XRD analysis and the functional group analysis was determined using Fourier transform infrared (FT-IR) spectroscopy. The morphology of the synthesized NPs was found to be a hexagonal shape using SEM and TEM analysis and elemental screening was analyzed using EDX. ZnO NPs were shown sized 40-45 nm and spherical in shape. The degradation percentage of ZnO NPs was calculated as 94% at 70 min and the rate of the reaction -k = 0.0282. The synthesized ZnO NPs were determined for effectiveness on biological activities such as antifungal, hemolytic, and antibacterial activity. ZnO NPs showed good antifungal activity against Alternaria saloni and Sclerrotium rolfii strains. Further, we have determined the hemolytic and antibacterial activity of ZnO NPs and we got successive results in antibacterial and hemolytic activities.

Effect of temperature on the characteristics of ZnO nanoparticles ...

Indian Academy of Sciences (India)

7

worked on self assembly of ZnO NPs produced by nanosecond pulsed laser ablation (PLA) in aqueous media [4]. They reported that the small ZnO nanoparticles were obtained .... monitor the optical properties of quantum-sized particles [17]. If the size of nanoparticles increases, their resonance absorption spectrum peak ...

Magnetic behavior of Co–Mn co-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Li, Hengda; Liu, Xinzhong; Zheng, Zhigong

2014-01-01

Here, we report on systematic studies of the magnetic properties of Co and Mn co-doped ZnO nanoparticles prepared by a sol–gel technique. The effect of the concentration of the doping ions on the magnetic properties of Co and Mn co-doped ZnO nanoparticles is presented. X-ray diffraction characterizations (XRD) of co-doped ZnO nanoparticles are all wurtzite structure. The Zn 0.96 Co 0.02 Mn 0.02 O nanoparticles and Zn 0.94 Co 0.02 Mn 0.04 O nanoparticles display ferromagnetic behavior at room temperature. Superconducting quantum interference device (SQUID) magnetometer figures show that with the concentration of the Mn ions increased, the saturation magnetic moment (M s ) increased, and the magnetic is probably due to the co-doping of the Mn ions. Our results demonstrate that the Mn ions doping concentration play an important role in the ferromagnetic properties of Co–Mn co-doped ZnO nanoparticles at room temperature. - Highlights: • The effect of the doping ions on the magnetic properties is presented. • The magnetic is probably due to the co-doping of the Mn ions. • The Mn ions concentration play an important role in the ferromagnetic properties

Effect of nickel doping concentration on structural and magnetic properties of ultrafine diluted magnetic semiconductor ZnO nanoparticles

International Nuclear Information System (INIS)

Sharma, Prashant K.; Dutta, Ranu K.; Pandey, Avinash C.

2009-01-01

The ZnO:Ni 2+ nanoparticles of mean size 2-12 nm were synthesized at room temperature by the simple co-precipitation method. The crystallite structure, morphology and size were determined by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The wurtzite structure of ZnO gradually degrades with the increasing Ni doping concentration and an additional NiO-associated diffraction peak was observed above 15% of Ni 2+ doping. The change in magnetic behavior of the nanoparticles of ZnO with varying Ni 2+ doping concentration was investigated using a vibrating sample magnetometer (VSM). Initially, these nanoparticles showed strong ferromagnetic behavior, however, at higher doping percentage of Ni 2+ , the ferromagnetic behavior was suppressed and paramagnetic nature was observed. The enhanced antiferromagnetic interaction between neighboring Ni-Ni ions suppressed the ferromagnetism at higher doping concentrations of Ni 2+ .

Synthesis and characterization of ZnO nanoparticles: Application to one-pot synthesis of benzo[b][1,5]diazepines

Directory of Open Access Journals (Sweden)

Mohammad Ali Ghasemzadeh

2015-12-01

Full Text Available The pharmaceutical and biologically active heterocyclic compounds including benzo[b][1,5]diazepines were efficiently synthesized via three-(in situ five- component reactions of aromatic diamines, Meldrum’s acid, and isocyanide derivatives in the presence of zinc oxide nanoparticles at room temperature. ZnO nanoparticles, as an effective, mild, and reusable catalyst, significantly improved the reaction times and also the products were obtained in excellent yields. The prepared zinc oxide nanoparticles were fully characterized by EDX, XRD, BET, SEM, IR, and TEM analyses.

Structural and optical properties of chromium doped zinc oxide nanoparticles synthesized by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Naqvi, Syed Mohd. Adnan, E-mail: adiaks2004@yahoo.co.in [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak (Malaysia); Irshad, Kashif, E-mail: alig.kashif@gmail.com [Department of Mechanical Engineering, Universiti Teknologi Petronas, Bandar Seri Iskandar, Perak (Malaysia); Soleimani, Hassan, E-mail: hassan.soleimani@petronas.com.my, E-mail: noorhana-yahya@petronas.com.my; Yahya, Noorhana, E-mail: hassan.soleimani@petronas.com.my, E-mail: noorhana-yahya@petronas.com.my

2014-10-24

Nanosized Cr-doped ZnO nano particles were synthesized by facile sol-gel auto combustion method. The structural and optical properties of Cr-doped ZnO nanoparticles have been investigated by XRD and UV-Vis spectroscopy at room temperature for 0% to 8% concentration. X-ray diffraction analysis reveals that the Cr-doped ZnO crystallizes in a single phase polycrystalline nature with wurtzite lattice. With every % of doping, the peaks are shifting scarcely and doping of Cr is possible up to 7%. After that, the last peak vanishes, that signifies its structure is transmuted from 8% doping. The average crystallite size decreases with increase in Cr concentration (i.e. 28.9 nm for 0% to 25.8 nm for 8%). The UV-Vis spectra of the nanoparticles betoken an incrementation in the band gap energy from 3.401, 3.415, 3.431, 3.437,3.453, 3.514,3.521, 3.530 and 3.538 eV respectively, for 0,1, 2, 3, 4, 5, 6, 7 and 8 % doping concentration.

Structural and optical properties of chromium doped zinc oxide nanoparticles synthesized by sol-gel method

International Nuclear Information System (INIS)

Naqvi, Syed Mohd. Adnan; Irshad, Kashif; Soleimani, Hassan; Yahya, Noorhana

2014-01-01

Nanosized Cr-doped ZnO nano particles were synthesized by facile sol-gel auto combustion method. The structural and optical properties of Cr-doped ZnO nanoparticles have been investigated by XRD and UV-Vis spectroscopy at room temperature for 0% to 8% concentration. X-ray diffraction analysis reveals that the Cr-doped ZnO crystallizes in a single phase polycrystalline nature with wurtzite lattice. With every % of doping, the peaks are shifting scarcely and doping of Cr is possible up to 7%. After that, the last peak vanishes, that signifies its structure is transmuted from 8% doping. The average crystallite size decreases with increase in Cr concentration (i.e. 28.9 nm for 0% to 25.8 nm for 8%). The UV-Vis spectra of the nanoparticles betoken an incrementation in the band gap energy from 3.401, 3.415, 3.431, 3.437,3.453, 3.514,3.521, 3.530 and 3.538 eV respectively, for 0,1, 2, 3, 4, 5, 6, 7 and 8 % doping concentration

Halloysite Nanotubes Supported Ag and ZnO Nanoparticles with Synergistically Enhanced Antibacterial Activity

Directory of Open Access Journals (Sweden)

Zhan Shu

2017-02-01

Full Text Available Abstract Novel antimicrobial nanocomposite incorporating halloysite nanotubes (HNTs and silver (Ag into zinc oxide (ZnO nanoparticles is prepared by integrating HNTs and decorating Ag nanoparticles. ZnO nanoparticles (ZnO NPs and Ag nanoparticles (Ag NPs with a size of about 100 and 8 nm, respectively, are dispersively anchored onto HNTs. The synergistic effects of ZnO NPs, Ag NPs, and HNTs led to the superior antibacterial activity of the Ag-ZnO/HNTs antibacterial nanocomposites. HNTs facilitated the dispersion and stability of ZnO NPs and brought them in close contact with bacteria, while Ag NPs could promote the separation of photogenerated electron-hole pairs and enhanced the antibacterial activity of ZnO NPs. The close contact with cell membrane enabled the nanoparticles to produce the increased concentration of reactive oxygen species and the metal ions to permeate into the cytoplasm, thus induced quick death of bacteria, indicating that Ag-ZnO/HNTs antibacterial nanocomposite is a promising candidate in the antibacterial fields.

Preparation of poly(N-vinylpyrrolidone-stabilized ZnO colloid nanoparticles

Directory of Open Access Journals (Sweden)

Tatyana Gutul

2014-04-01

Full Text Available We propose a method for the synthesis of a colloidal ZnO solution with poly(N-vinylpyrrolidone (PVP as stabilizer. Stable colloidal solutions with good luminescence properties are obtained by using PVP as stabilizer in the synthesis of ZnO nanoparticles by a sol–gel method assisted by ultrasound. Nanoparticles with sizes of 30–40 nm in a PVP matrix are produced as a solid product. The colloidal ZnO/PVP/methanol solution, apart from the most intense PL band at 356 nm coming from the PVP, exhibits a strong PL band at 376 nm (3.30 eV which corresponds to the emission of the free exciton recombination in ZnO nanoparticles.

Effects of hydrogen annealing on the room temperature ferromagnetism and optical properties of Cr-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Tong Liuniu; Wang Yichao; He Xianmei; Han Huaibin; Xia Ailin; Hu Jinlian

2012-01-01

We explore the effects of hydrogen annealing on the room temperature ferromagnetism and optical properties of Cr-doped ZnO nanoparticles synthesized by the sol-gel method. X-ray diffraction and x-ray photoelectron spectroscopy data show evidence that Cr has been incorporated into the wurtzite ZnO lattice as Cr 2+ ions substituting for Zn 2+ ions without any detectable secondary phase in as-synthesized Zn 0.97 Cr 0.03 O nanopowders. The room temperature magnetization measurements reveal a large enhancement of saturation magnetization M s as well as an increase of coercivity of H 2 -annealed Zn 0.97 Cr 0.03 O:H samples. It is found that the field-cooled magnetization curves as a function of temperature from 40 to 400 K can be well fitted by a combination of a standard Bloch spin-wave model and Curie–Weiss law. The values of the fitted parameters of the ferromagnetic exchange interaction constant a and the Curie constant C of H 2 -annealed Zn 0.97 Cr 0.03 O:H nanoparticles are almost doubled upon H 2 -annealing. Photoluminescence measurements show evidence that the shallow donor defect or/and defect complexes such as hydrogen occupying an oxygen vacancy H o may play an important role in the origin of H 2 -annealing induced enhancement of ferromagnetism in Cr-H codoped ZnO nanoparticles. - Graphical Abstract: The H 2 -annealing induced enhancement of room temperature ferromagnetism in Cr-doped ZnO nanoparticles is observed. It is found that the field-cooled M-T curves can be well fitted by a combination of a standard Bloch spin-wave model and Curie–Weiss law. The values of the fitted parameters of the ferromagnetic exchange interaction constant a and the Curie constant C of H 2 -annealed Zn 0.97 Cr 0.03 O:H nanoparticles are almost doubled upon H 2 -annealing. The PL data show evidence that the hydrogen related shallow donor defect or/and defect complexes may be responsible for it. Display Omitted Highlights: ► The H 2 -annealing induced a large enhancement of

Spectral features and antibacterial properties of Cu-doped ZnO nanoparticles prepared by sol-gel method

International Nuclear Information System (INIS)

Samavati, Alireza; Nur, Hadi; Othaman, Z; Ismail, A F; Mustafa, M K

2016-01-01

Zn 1−x Cu x O (x = 0.00, 0.01, 0.03, and 0.05) nanoparticles are synthesized via the sol-gel technique using gelatin and nitrate precursors. The impact of copper concentration on the structural, optical, and antibacterial properties of these nanoparticles is demonstrated. Powder x-ray diffraction investigations have illustrated the organized Cu doping into ZnO nanoparticles up to Cu concentration of 5% ( x = 0.05). However, the peak corresponding to CuO for x = 0.01 is not distinguishable. The images of field emission scanning electron microscopy demonstrate the existence of a nearly spherical shape with a size in the range of 30–52 nm. Doping Cu creates the Cu–O–Zn on the surface and results in a decrease in the crystallite size. Photoluminescence and absorption spectra display that doping Cu causes an increment in the energy band gap. The antibacterial activities of the nanoparticles are examined against Escherichia coli (Gram negative bacteria) cultures using optical density at 600 nm and a comparison of the size of inhibition zone diameter. It is found that both pure and doped ZnO nanoparticles indicate appropriate antibacterial activity which rises with Cu doping. (paper)

Chronic toxicity of ZnO nanoparticles, non-nano ZnO and ZnCl2 to Folsomia candida (Collembola) in relation to bioavailability in soil

International Nuclear Information System (INIS)

Kool, Pauline L.; Diez Ortiz, Maria; Gestel, Cornelis A.M. van

2011-01-01

The chronic toxicity of zinc oxide nanoparticles (ZnO-NP) to Folsomia candida was determined in natural soil. To unravel the contribution of particle size and free zinc to NP toxicity, non-nano ZnO and ZnCl 2 were also tested. Zinc concentrations in pore water increased with increasing soil concentrations, with Freundlich sorption constants K f of 61.7, 106 and 96.4 l/kg (n = 1.50, 1.34 and 0.42) for ZnO-NP, non-nano ZnO and ZnCl 2 respectively. Survival of F. candida was not affected by ZnO-NP and non-nano ZnO at concentrations up to 6400 mg Zn/kg d.w. Reproduction was dose-dependently reduced with 28-d EC50s of 1964, 1591 and 298 mg Zn/kg d.w. for ZnO-NP, non-nano ZnO and ZnCl 2 , respectively. The difference in EC50s based on measured pore water concentrations was small (7.94-16.8 mg Zn/l). We conclude that zinc ions released from NP determine the observed toxic effects rather than ZnO particle size. - Highlights: → ZnO nanoparticles and non-nano ZnO were equally toxic to Folsomia candida in soil. → Pore water from soil spiked with ZnO nanoparticles showed saturation with zinc suggesting aggregation. → Pore water based EC50 values for ZnO nanoparticles and ZnCl 2 were similar. → ZnO nanoparticle toxicity in soil was most probably due to Zn dissolution from the nanoparticles. - ZnO nanoparticle toxicity to springtails in soil can be explained from Zn dissolution but not from particle size.

Electronic structure, magnetic and structural properties of Ni doped ZnO nanoparticles

International Nuclear Information System (INIS)

Kumar, Shalendra; Vats, Prashant; Gautam, S.; Gupta, V.P.; Verma, K.D.; Chae, K.H.; Hashim, Mohd; Choi, H.K.

2014-01-01

Highlights: • XRD, and HR-TEM results show the single phase nature of Ni doped ZnO nanoparticles. • dc magnetization results indicate the RT-FM in Ni doped ZnO nanoparticles. • Ni L 3,2 edge NEXAFS spectra infer that Ni ions are in +2 valence state. • O K edge NEXAFS spectra show that O vacancy increases with Ni doping in ZnO. - Abstract: We report structural, magnetic and electronic structural properties of Ni doped ZnO nanoparticles prepared by auto-combustion method. The prepared nanoparticles were characterized by using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), near edge X-ray absorption fine structure (NEXAFS) spectroscopy, and dc magnetization measurements. The XRD and HR-TEM results indicate that Ni doped ZnO nanoparticles have single phase nature with wurtzite lattice and exclude the presence of secondary phase. NEXAFS measurements performed at Ni L 3,2 -edges indicates that Ni ions are in +2 valence state and exclude the presence of Ni metal clusters. O K-edge NEXAFS spectra indicate an increase in oxygen vacancies with Ni-doping, while Zn L 3,2 -edge show the absence of Zn-vacancies. The magnetization measurements performed at room temperature shows that pure and Ni doped ZnO exhibits ferromagnetic behavior

Structural, magnetic and electronic structure properties of Co doped ZnO nanoparticles

International Nuclear Information System (INIS)

Kumar, Shalendra; Song, T.K.; Gautam, Sanjeev; Chae, K.H.; Kim, S.S.; Jang, K.W.

2015-01-01

Highlights: • XRD and HR-TEM results show the single phase nature of Co doped ZnO nanoparticles. • XMCD and dc magnetization results indicate the RT-FM in Co doped ZnO nanoparticles. • Co L 3,2 NEXAFS spectra infer that Co ions are in 2+ valence state. • O K edge NEXAFS spectra show that O vacancy increases with Co doping in ZnO. - Abstract: We reported structural, magnetic and electronic structure studies of Co doped ZnO nanoparticles. Doping of Co ions in ZnO host matrix has been studied and confirmed using various methods; such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersed X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), near edge X-ray absorption fine structure (NEXAFS) spectroscopy, magnetic hysteresis loop measurements and X-ray magnetic circular dichroism (XMCD). From the XRD and HR-TEM results, it is observed that Co doped ZnO nanoparticles have single phase nature with wurtzite structure and exclude the possibility of secondary phase formation. FE-SEM and TEM micrographs show that pure and Co doped nanoparticles are nearly spherical in shape. O K edge NEXAFS spectra indicate that O vacancies increase with Co doping. The Co L 3,2 edge NEXAFS spectra revealed that Co ions are in 2+ valence state. DC magnetization hysteresis loops and XMCD results clearly showed the intrinsic origin of temperature ferromagnetism in Co doped ZnO nanoparticles

Role of nickel doping on structural, optical, magnetic properties and antibacterial activity of ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Vijayaprasath, G.; Murugan, R. [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Palanisamy, S.; Prabhu, N.M. [Department of Animal Health and Management, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011 (Japan); Ravi, G., E-mail: gravicrc@gmail.com [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

2016-04-15

Highlights: • The XRD analyses revealed that the synthesizes nickel doped ZnO (Zn{sub 1−x}Ni{sub x}O, x = 0.0, 0.03, 0.06 and 0.09) nanostructures have hexagonal wurtzite structure. • The photoluminescence measurements revealed that the broad emission was composed of different bands due to zinc and oxygen vacancies. • X-ray photoelectron spectroscopy (XPS) confirmed the Ni incorporation in ZnO lattice as Ni{sup 2+} ions. • Room temperature ferromagnetism was observed due to the oxygen vacancies and zinc interstitials are the main reasons for ferromagnetism in Ni doped ZnO NPs. - Abstract: Zn{sub 1−x}Ni{sub x}O nanoparticles were synthesized by co-precipitation method. The crystallite sizes of the synthesized samples found to decrease from 38 to 26 nm with increase in nickel concentration. FTIR spectra confirmed the presence of Zn−O stretching bands at 577, 573, 569 and 565 cm{sup −1} in the respective ZnO NPs. Optical absorption spectra revealed the red shifted and estimated band gap is found to decrease with increase of Ni doping concentration. The PL spectra of all the samples exhibited a broad emission at 390 nm in the visible range. The carriers (donors) bounded on the Ni sites were observed from the micro Raman spectroscopic studies. Pure and Ni doped ZnO NPs showed significant changes in the M–H loop, especially the diamagnetic behavior changed into ferromagnetic nature for Ni doped samples. The antiferromagnetic super-exchange interactions between Ni{sup 2+} ions is increased in higher Ni doped ZnO NPs and also their antibacterial activity has been studied.

Structural and room temperature ferromagnetic properties of Ni doped ZnO nanoparticles via low-temperature hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Xu, Kun; Liu, Changzhen, E-mail: liuchangzhen94@163.com; Chen, Rui; Fang, Xiaoxiang; Wu, Xiuling; Liu, Jie

2016-12-01

A series of Zn{sub 1−x}Ni{sub x}O (x=0, 1%, 3%, 5%) nanoparticles have been synthesized via a low-temperature hydrothermal method. Influence of Ni doping concentration on the structure, morphology, optical properties and magnetism of the samples was investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–vis spectrophotometer and vibrating sample magnetometer instruments. The results show that the undoped and doped ZnO nanoparticles are both hexagonal wurtzite structures. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The images of SEM reveal that the structure of pure ZnO and Ni doped samples are nanoparticles which intended to form flakes with thickness of few nanometers, being overlain with each one to develop the network with some pores and voids. Based on the ultraviolet–visible (UV–vis) spectroscopy analysis, it indicates that the band gap energy decreases with the increasing concentration of Ni. Furthermore, The Ni doped ZnO samples didn't exhibit higher ultraviolet-light-driven photocatalytic activity compared to the undoped ZnO sample. Vibrating sample magnetometer was used for the magnetic property investigations, and the result indicates that room temperature ferromagnetism property of 3% Ni doped sample is attributed to oxygen vacancy and interaction between doped ions.

Fabrication of highly dispersed ZnO nanoparticles embedded in graphene nanosheets for high performance supercapacitors

International Nuclear Information System (INIS)

Fang, Linxia; Zhang, Baoliang; Li, Wei; Zhang, Jizhong; Huang, Kejing; Zhang, Qiuyu

2014-01-01

We report a facile strategy to synthesize ZnO-graphene nanocomposites as an advanced electrode material for high-performance supercapacitors. The ZnO-graphene nanocomposites have been fabricated via a facile, low-temperature in situ wet chemistry process. During this process, high dispersed ZnO nanoparticles are embedded in graphene nanosheets, leading to sandwich-structured ZnO-graphene nanocomposites. Thus, intimate interfacial contact between ZnO nanoparticles and graphene nanosheets are achieved, which facilitates electrochemical activity and enhance electrochemical properties due to fast electron transfer. The as-prepared ZnO-graphene nanocomposites exhibit a maximum specific capacitance of 786 F g −1 and excellent cycle life with capacity retention of about 92% after 500 cycles. This facile design and rational synthesis offers an effective strategy to enhance the electrochemical performance of supercapacitors and shows promising potential for large-scale application in energy storage

Electrical, dielectric and photocatalytic properties of Fe-doped ZnO nanomaterials synthesized by sol gel method

Directory of Open Access Journals (Sweden)

Yacine Cherif

2016-09-01

Full Text Available Fe-doped ZnO nanoparticles were synthesized by sol gel technique. Fine-scale and single phase hexagonal wurtzite structure in all samples were confirmed by SEM and XRD, respectively. The band gap energy depends on the amount of Fe and was found to be in the range of 3.11–2.53 eV. The electric and dielectric properties were investigated using complex impedance spectroscopy. AC conductivity data were correlated with the barrier hopping (CBH model to evaluate the binding energy (Wm, the minimum hopping distance (Rmin and the density of states at Fermi level, N(EF. Fe doping in ZnO also improved the photocatalytic activity. Thus, the sample Zn0.95Fe0.05O showed high degradation potential towards methylene blue (MB, i.e. it degrades 90% of BM in 90 min under UV light.

Zn nanoparticle formation in FIB irradiated single crystal ZnO

Science.gov (United States)

Pea, M.; Barucca, G.; Notargiacomo, A.; Di Gaspare, L.; Mussi, V.

2018-03-01

We report on the formation of Zn nanoparticles induced by Ga+ focused ion beam on single crystal ZnO. The irradiated materials have been studied as a function of the ion dose by means of atomic force microscopy, scanning electron microscopy, Raman spectroscopy and transmission electron microscopy, evidencing the presence of Zn nanoparticles with size of the order of 5-30 nm. The nanoparticles are found to be embedded in a shallow amorphous ZnO matrix few tens of nanometers thick. Results reveal that ion beam induced Zn clustering occurs producing crystalline particles with the same hexagonal lattice and orientation of the substrate, and could explain the alteration of optical and electrical properties found for FIB fabricated and processed ZnO based devices.

Growth and characterization of ZnO nanowires for optical applications

International Nuclear Information System (INIS)

AlSalhi, M S; Atif, M; Ansari, A A; Khun, K; Ibupoto, Z H; Willander, M

2013-01-01

In the present work, cerium oxide CeO 2 nanoparticles were synthesized by the sol–gel method and used for the growth of ZnO nanorods. The synthesized nanoparticles were studied by x-ray diffraction (XRD) and Raman spectroscopic techniques. Furthermore, these nanoparticles were used as the seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by means of field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and XRD techniques. This study demonstrated that the grown ZnO nanorods are well aligned, uniform, of good crystal quality and have diameters of less than 200 nm. Energy dispersive x-ray (EDX) analysis revealed that the ZnO nanorods are composed only of zinc, cerium as the seed atom, and oxygen atoms, with no other impurities in the grown nanorods. Moreover, a photoluminescence (PL) approach was applied for the optical characterization, and it was observed that the near-band-edge (NBE) emission was the same as that of the zinc acetate seed layer, however the green and orange/red emission peaks were slightly raised due to possibly higher levels of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the controlled synthesis of ZnO nanorods using cerium oxide nanoparticles as the seed nucleation layer, improving both the morphology of the nanorods and the performance of devices based upon them. (paper)

Blue shift in the luminescence spectra of MEH-PPV films containing ZnO nanoparticles

International Nuclear Information System (INIS)

Ton-That, Cuong; Phillips, Matthew R.; Nguyen, Thien-Phap

2008-01-01

Luminescence properties of nanocomposites consisting of ZnO nanoparticles in a conjugated polymer, poly [2-methoxy-5-(2'-ethyl hexyloxy)-phenylene vinylene] (MEH-PPV), were investigated. Photoluminescence measurements reveal a blue shift in the emission spectrum of MEH-PPV upon incorporation of ZnO nanoparticles into the polymer film while the emission is increasingly quenched with increasing ZnO concentration. In contrast, the structure of the polymer and its conjugation length are not affected by the presence of ZnO nanoparticles (up to 16 wt% ZnO) as revealed by Raman spectroscopy. The blue shift and photoluminescence quenching are explained by the separation of photogenerated electron-hole pairs at the MEH-PPV/ZnO interface and the charging of the nanoparticles

Carbon doped ZnO: Synthesis, characterization and interpretation

International Nuclear Information System (INIS)

Mishra, D.K.; Mohapatra, J.; Sharma, M.K.; Chattarjee, R.; Singh, S.K.; Varma, Shikha; Behera, S.N.; Nayak, Sanjeev K.; Entel, P.

2013-01-01

A novel thermal plasma in-flight technique has been adopted to synthesize nanocrystalline ZnO and carbon doped nanocrystalline ZnO matrix. Transmission electron microscopy (TEM) studies on these samples show the average particle sizes to be around 32 nm for ZnO and for carbon doped ZnO. An enhancement of saturation magnetization in nanosized carbon doped ZnO matrix by a factor of 3.8 has been found in comparison to ZnO nanoparticles at room temperature. Raman measurement clearly indicates the presence of Zn–C complexes surrounded by ZnO matrix in carbon doped ZnO. This indicates that the ferromagnetic signature in carbon doped ZnO arises from the creation of defects or the development of oxy-carbon clusters, in the carbon doped ZnO system. Theoretical studies based on density functional theory also support the experimental analyses. - Highlights: ► Synthesis of nanocrystalline ZnO and carbon doped ZnO matrix by inflight thermal plasma reactor. ► Enhancement of ferromagnetism in nanosized carbon doped ZnO in comparison to ZnO nanoparticles. ► Raman measurement indicates the presence of Zn–C complexes surrounded by ZnO matrix. ► Ferromagnetic signature in carbon doped ZnO arises from the development of oxy-carbon clusters. ► DFT supports experimental evidence of ferromagnetism in C doped ZnO nanoparticles.

Chronic toxicity of ZnO nanoparticles, non-nano ZnO and ZnCl{sub 2} to Folsomia candida (Collembola) in relation to bioavailability in soil

Energy Technology Data Exchange (ETDEWEB)

Kool, Pauline L., E-mail: pauline.kool@falw.vu.nl [Department of Animal Ecology, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Diez Ortiz, Maria [Department of Animal Ecology, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Pole de Recherche ROVALTAIN en Toxicologie Environnementale et Ecotoxicologie, Batiment Rhovalparc, BP 15173, 26958 Valence Cedex 9 (France); Gestel, Cornelis A.M. van [Department of Animal Ecology, Faculty of Earth and Life Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)

2011-10-15

The chronic toxicity of zinc oxide nanoparticles (ZnO-NP) to Folsomia candida was determined in natural soil. To unravel the contribution of particle size and free zinc to NP toxicity, non-nano ZnO and ZnCl{sub 2} were also tested. Zinc concentrations in pore water increased with increasing soil concentrations, with Freundlich sorption constants K{sub f} of 61.7, 106 and 96.4 l/kg (n = 1.50, 1.34 and 0.42) for ZnO-NP, non-nano ZnO and ZnCl{sub 2} respectively. Survival of F. candida was not affected by ZnO-NP and non-nano ZnO at concentrations up to 6400 mg Zn/kg d.w. Reproduction was dose-dependently reduced with 28-d EC50s of 1964, 1591 and 298 mg Zn/kg d.w. for ZnO-NP, non-nano ZnO and ZnCl{sub 2}, respectively. The difference in EC50s based on measured pore water concentrations was small (7.94-16.8 mg Zn/l). We conclude that zinc ions released from NP determine the observed toxic effects rather than ZnO particle size. - Highlights: > ZnO nanoparticles and non-nano ZnO were equally toxic to Folsomia candida in soil. > Pore water from soil spiked with ZnO nanoparticles showed saturation with zinc suggesting aggregation. > Pore water based EC50 values for ZnO nanoparticles and ZnCl{sub 2} were similar. > ZnO nanoparticle toxicity in soil was most probably due to Zn dissolution from the nanoparticles. - ZnO nanoparticle toxicity to springtails in soil can be explained from Zn dissolution but not from particle size.

Enhanced room temperature ferromagnetism in Cr-doped ZnO nanoparticles prepared by auto-combustion method

Science.gov (United States)

Haq, Khizar-ul; Irfan, M.; Masood, Muhammad; Saleem, Murtaza; Iqbal, Tahir; Ahmad, Ishaq; Khan, M. A.; Zaffar, M.; Irfan, Muhammad

2018-04-01

Zn1‑x Cr x O (x = 0.00, 0.01, 0.03, 0.05, 0.07, and 0.09) nanoparticles were synthesized, by an auto-combustion method. Structural, optical, and magnetic characteristics of Cr-doped ZnO samples calcined at 600 °C have been analyzed by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), UV–Vis spectroscopy and vibrating sample magnetometer (VSM). The XRD data confirmed the hexagonal wurtzite structure of pure and Cr-doped ZnO nanoparticles. The calculated values of grain size using Scherrer's formula are in the range of 30.7–9.2 nm. The morphology of nanopowders has been observed by FESEM, and EDS results confirmed a systematic increase of Cr content in the samples and clearly indicate with no impurity element. The band gaps, computed by UV–Vis spectroscopy, are in the range of 2.83–2.35 eV for different doping concentrations. By analyzing VSM data, significantly enhanced room temperature ferromagnetism is identified in Cr-doped ZnO samples. The value of magnetization is a 12 times increased of the value reported by Daunet al. (2010). Room temperature ferromagnetism of the nanoparticles is of vital prominence for spintronics applications. Project supported by the Office of Research, Innovation, and Commercialization (ORIC), MUST Mirpur (AJK).

Synthesis and characterization of ZnO nanoparticles for photocatalysis application

Energy Technology Data Exchange (ETDEWEB)

Mazzo, Tatiana Martelli; Minervino, Gabriela Bosco; Medalha Filho, Carlos Alberto, E-mail: tatimazzo@gmail.com [Universidade Federal de Sao Paulo (UNIFESP), Baixada Santista, SP (Brazil); Oliveira, Regiane Cristina; Longo, Elson [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

2016-07-01

Full text: The search for more effective ways to prevent and remedy environmental problems has a strong academic and technological appeal. Based on the study of a variety of compounds, zinc oxide (ZnO) is an excellent candidate for the synthesis of multifunctional nanoparticles due to their potential technological application in various fields [1]. In this work, we were synthesized flowers-like ZnO by coprecipitation and hydrothermal microwave methods. All materials were characterized by X-Ray Diffraction, Micro-Raman spectroscopy and scanning electron microscopy. All XRD patterns correspond to hexagonal structure, which is in agreement with the respective JCPDS card no. 36-1451 for pure ZnO phase with group space group (P63mc) and two molecular formula units per unit cell (Z = 2). Analysis of Micro-Raman spectroscopy showed the presence of vibrational modes in all samples and confirmed the hexagonal ZnO structure. The microscopy images clearly show a change of the morphology of the sample obtained by the co- precipitation method in comparison with those obtained by hydrothermal microwave method. In accordance with the photodegradation the results revealed that the ZnO processed at 140 deg C for 32 minutes have higher photocatalytic efficiency degradation. The Rodamine B dye was completely decolorized at 30 minutes. The pseudo-first order model indicate an increasing in the (k) values with the increase microwave processing time and that improve the ZnO photocatalytic performance. In this work we reported a low-temperature way to prepare the ZnO photocatalytic semiconductor and the results showed a great potential of this material for that application. References: [1] Pearton, S. J; Norton, D. P; et al, Journal of Science and Technology. 22 (2004) 932-948 [2] Kansal, S. K.; Kaur, N. Nanoscale Research Letters 4 (2009) 709-716. (author)

Local transport properties, morphology and microstructure of ZnO decorated SiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Van Nostrand, Joseph E [Air Force Research Laboratory, Information Directorate, Rome, NY (United States); Cortez, Rebecca [Union College, Schenectady, NY (United States); Rice, Zachary P; Cady, Nathaniel C; Bergkvist, Magnus, E-mail: Joseph.VanNostrand@rl.af.mil [Albany College of Nanoscale Science and Engineering, Albany, NY (United States)

2010-10-15

We report on a novel, surfactant free method for achieving nanocrystalline ZnO decoration of an SiO{sub 2} nanoparticle at ambient temperature. The size distributions of the naked and decorated SiO{sub 2} nanoparticles are measured by means of dynamic light scattering, and a monodisperse distribution is observed for each. The morphology and microstructure of the nanoparticles are explored using atomic force microscopy and high resolution transmission electron microscopy. Investigation of the optical properties of the ZnO decorated SiO{sub 2} nanoparticles shows absorption at 350 nm. This blue shift in absorption as compared to bulk ZnO is shown to be consistent with quantum confinement effects due to the small size of the ZnO nanocrystals. Finally, the local electronic transport properties of the nanoparticles are explored by scanning conductance atomic force microscopy. A memristive hysteresis in the transport properties of the individual ZnO decorated SiO{sub 2} nanoparticles is observed. Optical absorption measurements suggest the presence of oxygen vacancies, whose migration and annihilation appear to contribute to the dynamic conduction properties of the ZnO decorated nanoparticles. We believe this to be the first demonstration of a ZnO decorated SiO{sub 2} nanoparticle, and this represents a simple yet powerful way of achieving the optical and electrical properties of ZnO in combination with the simplicity of SiO{sub 2} synthesis.

The SL-assisted synthesis of hierarchical ZnO nanostructures and their enhanced photocatalytic activity

International Nuclear Information System (INIS)

Miao Tingting; Guo Yuanru; Pan Qingjiang

2013-01-01

Hierarchical ZnO nanoparticle-bar, nanomesh-lamina, and quasi-nanosphere structures have been successfully synthesized by the precipitation method with assistance of sodium lignosulphonate (SL). It is shown that the obtained ZnO nanomaterials are well crystallized and possess hexagonal wurtzite structure after calcination. Morphologies of ZnO with particle sizes ranging from 50 to 200 nm can be fabricated by tuning the SL amount in our synthetic route. Plenty of pores have been observed both in nanoparticle-bar and nanomesh-lamina ZnO. This may provide scaffold microenvironments to enhance their photocatalytic activity. It is evident that the synthesized ZnO exhibits good photocatalytic activity of degrading methylene blue, even under a very low-power UV illumination, which allows for the treatment of wastewater containing organic pollutants in an effective way. Among our synthesized nanomaterials, the nanomesh-lamina ZnO has the highest photodegradation efficiency, achieving nearly 100 % degradation only within 1.5 h (UV irradiation power of 12 W). As these ZnO nanomaterials are simply synthesized using SL which is a pulp industry by-product and their intrinsic hierarchical nanostructures show outstanding photocatalytic behavior, we expect the present controllable, environment-friendly, and cost-effective approach to be applied in the synthesis of small-sized ZnO materials.

The SL-assisted synthesis of hierarchical ZnO nanostructures and their enhanced photocatalytic activity

Science.gov (United States)

Miao, Ting-Ting; Guo, Yuan-Ru; Pan, Qing-Jiang

2013-06-01

Hierarchical ZnO nanoparticle-bar, nanomesh-lamina, and quasi-nanosphere structures have been successfully synthesized by the precipitation method with assistance of sodium lignosulphonate (SL). It is shown that the obtained ZnO nanomaterials are well crystallized and possess hexagonal wurtzite structure after calcination. Morphologies of ZnO with particle sizes ranging from 50 to 200 nm can be fabricated by tuning the SL amount in our synthetic route. Plenty of pores have been observed both in nanoparticle-bar and nanomesh-lamina ZnO. This may provide scaffold microenvironments to enhance their photocatalytic activity. It is evident that the synthesized ZnO exhibits good photocatalytic activity of degrading methylene blue, even under a very low-power UV illumination, which allows for the treatment of wastewater containing organic pollutants in an effective way. Among our synthesized nanomaterials, the nanomesh-lamina ZnO has the highest photodegradation efficiency, achieving nearly 100 % degradation only within 1.5 h (UV irradiation power of 12 W). As these ZnO nanomaterials are simply synthesized using SL which is a pulp industry by-product and their intrinsic hierarchical nanostructures show outstanding photocatalytic behavior, we expect the present controllable, environment-friendly, and cost-effective approach to be applied in the synthesis of small-sized ZnO materials.

Recovery of thermal-degraded ZnO photodetector by embedding nano silver oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hu, Zhan-Shuo [Institute of Microelectronics, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hung, Fei-Yi, E-mail: fyhung@mail.ncku.edu.tw [Institute of Nanotechnology and Microsystems Engineering, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Chen, Kuan-Jen [Institute of Nanotechnology and Microsystems Engineering, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); The Instrument Center, National Cheng Kung University, Tainan 701, Taiwan (China); Chang, Shoou-Jinn [Institute of Microelectronics, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hsieh, Wei-Kang; Liao, Tsai-Yu; Chen, Tse-Pu [Institute of Microelectronics, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China)

2013-08-15

The degraded performance of annealed ZnO-based photodetector can be recovered by embedding Ag{sub 2}O nanoparticles resulted from the transformation of as-deposited Ag layer. After thermal treatment, the electrons were attracted at the interface between ZnO and Ag{sub 2}O. The excess Ag{sup +} ions form the cluster to incorporate into the interstitial sites of ZnO lattice to create a larger amount of lattice defects for the leakage path. The photo-current of ZnO film with Ag{sub 2}O nanoparticles is less than annealed ZnO film because the photo-induced electrons would flow into Ag{sub 2}O side. ZnO photodetector with the appropriate Ag{sub 2}O nanoparticles possesses the best rejection ratio.

The influence of vacuum and annealing on the visible luminescence in ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

P R, Chithira; Theresa John, Teny, E-mail: teny@goa.bits-pilani.ac.in

2017-05-15

The ZnO nanoparticles synthesized by a simple solution based chemical bath deposition method were characterized using different experimental techniques. Photoluminescence (PL) studies were performed in ambient as well as in vacuum conditions. The emission spectra exhibit two bands corresponding to UV emission at 380 nm and a wide visible luminescence centered at 571 nm due to surface defects in ambient conditions. Under vacuum condition, the spectra show a reduction in the intensity of the wide visible luminescence and an enhancement in the UV emission. These nanoparticles were annealed at high temperatures in air. The wide visible luminescence remains at the same intensity in both ambient and in vacuum condition for the annealed samples indicating that some of the surface adsorbed defects are removed due to annealing. Fourier Transform Infrared Spectroscopy (FTIR) and Electron Spin Resonance (ESR) results reveal the presence of [OH{sup -}] related groups on the surface of the samples. An analysis of the O1s peak in ZnO using X-ray Photoelectron Spectroscopy (XPS) measurement confirms the presence of intrinsic defects such as oxygen related vacancies and adsorbed oxygen species in the sample. Our investigation shows that the green emission observed in ZnO samples is primarily due to oxygen vacancies.

The influence of vacuum and annealing on the visible luminescence in ZnO nanoparticles

International Nuclear Information System (INIS)

P R, Chithira; Theresa John, Teny

2017-01-01

The ZnO nanoparticles synthesized by a simple solution based chemical bath deposition method were characterized using different experimental techniques. Photoluminescence (PL) studies were performed in ambient as well as in vacuum conditions. The emission spectra exhibit two bands corresponding to UV emission at 380 nm and a wide visible luminescence centered at 571 nm due to surface defects in ambient conditions. Under vacuum condition, the spectra show a reduction in the intensity of the wide visible luminescence and an enhancement in the UV emission. These nanoparticles were annealed at high temperatures in air. The wide visible luminescence remains at the same intensity in both ambient and in vacuum condition for the annealed samples indicating that some of the surface adsorbed defects are removed due to annealing. Fourier Transform Infrared Spectroscopy (FTIR) and Electron Spin Resonance (ESR) results reveal the presence of [OH - ] related groups on the surface of the samples. An analysis of the O1s peak in ZnO using X-ray Photoelectron Spectroscopy (XPS) measurement confirms the presence of intrinsic defects such as oxygen related vacancies and adsorbed oxygen species in the sample. Our investigation shows that the green emission observed in ZnO samples is primarily due to oxygen vacancies.

Preparation, structural and optical characterization of ZnO, ZnO: Al nanopowder

Energy Technology Data Exchange (ETDEWEB)

Mohan, R. Raj [Department of ECE, Gojan School of Business and Technology, Chennai (India); Rajendran, K. [Department of Electronics, Government Arts College for Women, Ramanathapuram, TN (India); Sambath, K. [Department of ECS, Sri Krishna Arts and Science College, Coimbatore, TN (India)

2014-01-28

In this paper, ZnO and ZnO:Al nanopowders have been synthesized by low cost hydrothermal method. Zinc nitrate, hexamethylenetetramine (HMT) and aluminium nitrate are used as precursors for ZnO and AZO with different molar ratios. The structural and optical characterization of doped and un-doped ZnO powders have been investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDAX), photoluminescence (PL) and ultra violet visible (UV-Vis) absorption studies. The SEM results show that the hydrothermal synthesis can be used to obtain nanoparticles with different morphology. It is observed that the grain size of the AZO nanoparticles increased with increasing of Al concentration. The PL measurement of AZO shows that broad range of green emission around 550nm with high intensity. The green emission resulted mainly because of intrinsic defects.

ROS-dependent anticandidal activity of zinc oxide nanoparticles synthesized by using egg albumen as a biotemplate

International Nuclear Information System (INIS)

Shoeb, M; Singh, Braj R; Khan, Javed A; Khan, Wasi; Naqvi, Alim H; Singh, Brahma N; Singh, Harikesh B

2013-01-01

Zinc oxide nanoparticles (ZnO NPs) have attracted great attention because of their superior optical properties and wide application in biomedical science. However, little is known about the anticandidal activity of ZnO NPs against Candida albicans (C. albicans). This study was designed to develop the green approach to synthesize ZnO NPs using egg white (denoted as EtZnO NPs) and investigated its possible mechanism of antimicrobial activity against C. albicans 077. It was also notable that anticandidal activity of EtZnO NPs is correlated with reactive oxygen species (ROS) production in a dose dependent manner. Protection of histidine against ROS clearly suggests the implication of ROS in anticandidal activity of EtZnO NPs. This green approach based on egg white-mediated synthesis of ZnO NPs paves the way for developing cost effective, eco-friendly and promising antimicrobial nanomaterial for applications in medicine. (paper)

Rapid synthesis of Co, Ni co-doped ZnO nanoparticles: Optical and electrochemical properties

Energy Technology Data Exchange (ETDEWEB)

Romeiro, Fernanda C.; Marinho, Juliane Z.; Lemos, Samantha C.S. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Moura, Ana P. de [LIEC, Instituto de Química, Universidade Estadual Paulista, 14800-900 Araraquara, SP (Brazil); Freire, Poliana G. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Silva, Luis F. da; Longo, Elson [LIEC, Instituto de Química, Universidade Estadual Paulista, 14800-900 Araraquara, SP (Brazil); Munoz, Rodrigo A.A. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Lima, Renata C., E-mail: rclima@iqufu.ufu.br [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil)

2015-10-15

We report for the first time a rapid preparation of Zn{sub 1−2x}Co{sub x}Ni{sub x}O nanoparticles via a versatile and environmentally friendly route, microwave-assisted hydrothermal (MAH) method. The Co, Ni co-doped ZnO nanoparticles present an effect on photoluminescence and electrochemical properties, exhibiting excellent electrocatalytic performance compared to undoped ZnO sample. Photoluminescence spectroscopy measurements indicated the reduction of the green–orange–red visible emission region after adding Co and Ni ions, revealing the formation of alternative pathways for the generated recombination. The presence of these metallic ions into ZnO creates different defects, contributing to a local structural disorder, as revealed by Raman spectra. Electrochemical experiments revealed that the electrocatalytic oxidation of dopamine on ZnO attached to multi-walled carbon nanotubes improved significantly in the Co, Ni co-doped ZnO samples when compared to pure ZnO. - Graphical abstract: Rapid synthesis of Co, Ni co-doped ZnO nanoparticles: optical and electrochemical properties. Co, Ni co-doped ZnO hexagonal nanoparticles with optical and electrocatalytic properties were successfully prepared for the first time using a microwave hydrothermal method at mild conditions. - Highlights: • Co{sup 2+} and Ni{sup 2+} into ZnO lattice obtained a mild and environmentally friendly process. • The heating method strongly influences in the growth and shape of the particles. • Short-range defects generated by the ions insertion affects the photoluminescence. • Doped ZnO nanoparticles improve the electrocatalytic properties of pure oxide.

ZnO/SnO{sub 2} nanoflower based ZnO template synthesized by thermal chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Sin, N. D. Md., E-mail: diyana0366@johor.uitm.edu.my; Amalina, M. N., E-mail: amalina0942@johor.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Fakulti Kejuruteraan Elektrik, Universiti Teknologi MARA Cawangan Johor, Kampus Pasir Gudang, 81750 Masai, Johor (Malaysia); Ismail, Ahmad Syakirin, E-mail: kyrin-samaxi@yahoo.com; Shafura, A. K., E-mail: shafura@ymail.com; Ahmad, Samsiah, E-mail: samsiah.ahmad@johor.uitm.edu.my; Mamat, M. H., E-mail: mhmamat@salam.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M., E-mail: rusop@salam.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia)

2016-07-06

The ZnO/SnO{sub 2} nanoflower like structures was grown on a glass substrate deposited with seed layer using thermal chemical vapor deposition (CVD) with combining two source materials. The ZnO/SnO{sub 2} nanoflower like structures had diameter in the range 70 to 100 nm. The atomic percentage of ZnO nanoparticle , SnO{sub 2} nanorods and ZnO/SnO{sub 2} nanoflower was taken using EDS. Based on the FESEM observations, the growth mechanism is applied to describe the growth for the synthesized nanostructures.

Photoluminescence of Sequential Infiltration Synthesized ZnO nanostructures

Science.gov (United States)

Ocola, Leonidas; Gosztola, David; Yanguas-Gil, Angel; Connolly, Aine

We have investigated a variation of atomic layer deposition (ALD), called sequential infiltration synthesis (SiS), as an alternate method to incorporate ZnO and other oxides inside polymethylmethacrylate (PMMA) and other polymers. Energy dispersive spectroscopy (EDS) results show that we synthesize ZnO up to 300 nm inside a PMMA film. Photoluminescence data on a PMMA film shows that we achieve a factor of 400X increase in photoluminescence (PL) intensity when comparing a blank Si sample and a 270 nm thick PMMA film, where both were treated with the same 12 alternating cycles of H2O and diethyl zinc (DEZ). PMMA is a well-known ebeam resist. We can expose and develop patterns useful for photonics or sensing applications first, and then convert them afterwards into a hybrid polymer-oxide material. We show that patterning does indeed affect the photoluminescence signature of native ZnO. We demonstrate we can track the growth of the ZnO inside the PMMA polymer using both photoluminescence and Raman spectroscopy and determine the point in the process where ZnO is first photoluminescent and also at which point ZnO first exhibits long range order in the polymer. This work was supported by the Department of Energy under Contract No. DE-AC02-06CH11357. Use of the Center for Nanoscale Materials was supported by the U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

Catalytic degradation of Amlodipine Besylate using ZnO, Cu doped ZnO, and Fe doped ZnO nanoparticles from an aqueous solution: Investigating the effect of different parameters on degradation efficiency

Science.gov (United States)

Alizadeh, Elahe; Baseri, Hadi

2018-04-01

Some common nanoparticles, such as Zinc Oxide have been used as nanocatalysts in many processes, but they also have an important application in water purification processes. In this research, ZnO based nanoparticles were used for the degradation of Amlodipine Besylate (AMB) and the effect of some main parameters, e.g. initial concentration of AMB, nanocatalysts dose, pH of the solution, temperature of the solution, H2O2 dose, and the time of visible light irradiation, were investigated. The destruction amount was determined by UV-Vis spectroscopy. The synthesized nanoparticles were characterized by FE-SEM, XRD, FT-IR, BET, BJH, EDS, XRF and UV-Vis techniques. The maximum degradation of AMB was about 90% in 60 min of visible light irradiation with 100 μL of H2O2.

Comparative study of Ni and Cu doped ZnO nanoparticles: Structural and optical properties

Science.gov (United States)

Thakur, Shaveta; Thakur, Samita; Sharma, Jyoti; Kumar, Sanjay

2018-05-01

Nanoparticles of undoped and doped (0.1 M Ni2+ and Cu2+) ZnO are synthesized using chemical precipitation method. The crystallite size, morphology, chemical bonding and optical properties of as prepared nanoparticles are determined by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and UV-visible spectra. XRD analysis shows that the prepared samples are single phase and have hexagonal wurtzite structure. The crystallite size of the doped and undoped nanoparticles is determined using Scherrer method. The crystallite size is found to be increased with concentration of nickel and copper. All stretching and vibrational bands are observed at their specific positions through FTIR. The increase in band gap can be attributed to the different chemical nature of dopant and host cation.

Magnetic nanoparticles as a seed layer for growing ZnO nanowires for optical applications

International Nuclear Information System (INIS)

AlSalhi, M S; Atif, M; Ansari, Anees A; Khun, K; Ibupoto, Z H; Willander, M

2013-01-01

In the present work, cerium oxide CeO 2 nanoparticles were synthesised by sol-gel method and used for the growth of ZnO nanorods. The synthesised nanoparticles were studied by x-ray diffraction technique [XRD]. Furthermore, these nanoparticles were used as seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by using field emission scanning electron microscopy [FESEM], and x-ray diffraction [XRD] techniques. This study demonstrated that the grown ZnO nanorods are well align, uniform, good in crystal quality and possess diameter of less than 200 nm. Energy dispersive x-rays [EDX] revealed that the ZnO nanorods are only composed of zinc, cerium as seed atom and oxygen atoms and no any other impurity in the grown nanorods. Moreover, photoluminescence [PL] approach was applied for the optical characterisation and it was observed that the near-band-edge emission [NBE] was same to that of zinc acetate seed layer, however the green emission and orange/red emission peaks were slightly raised due to possible higher level of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the synthesis of controlled ZnO nanorods using cerium oxide nanoparticles as seed nucleation layer which in reverse describe the application of these nanoparticles as well as due to controlled morphology of ZnO nanorods the performance of nanodevices based on ZnO can be increased using these particles as seed.

Fabrication and characterizations of ZnO nanorods/Au nanoparticle composites on the electropolished Ti substrate

Energy Technology Data Exchange (ETDEWEB)

Chen, Hsiang, E-mail: hchen@ncnu.edu.tw [National Chi Nan University, No.1, Daxue Rd., Puli Township, Nantou County 545, Taiwan, ROC (China); Yeh, Yih-Min [WuFeng University, No. 117, Sec 2, Chiankuo Rd, Minhsiung, Chiayi County 62153, Taiwan, ROC (China); Chen, Jian-Zhi [National Chi Nan University, No.1, Daxue Rd., Puli Township, Nantou County 545, Taiwan, ROC (China); Liu, Song-Ming [WuFeng University, No. 117, Sec 2, Chiankuo Rd, Minhsiung, Chiayi County 62153, Taiwan, ROC (China); Huang, Bo Yun; Wu, Zhi-Huei; Tsai, Shaung-Lin; Chang, Hung-Wei; Chu, Yu-Cheng; Liao, Chuan Hao [National Chi Nan University, No.1, Daxue Rd., Puli Township, Nantou County 545, Taiwan, ROC (China)

2013-12-31

Au nanoparticles (NPs) were spread on ZnO nanorods (NRs) on the polished Ti substrate to form Au/ZnO nanocomposites. Multiple material analyses including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) analyses, Fourier-transform infrared spectrometer (FTIR) and images taken by optical microscope were performed on Au NPs of 2 nm and 20 nm on ZnO NRs. The FESEM and optical images under optical microscope indicate that 20 nm NPs can form more and larger clusters than 2 nm NPs on ZnO nanorod. Furthermore, more Au can be detected by EDS and XRD. We studied the behaviors of Au NPs on ZnO NR applications for future potential biosensing and antiseptic devices. - Highlights: • Nanocomposites of Au nanoparticles were spread on ZnO nanorods on Ti substrate. • Multiple material analyses were performed on 2 nm and 20 nm nanoparticles. • 20 nm nanoparticles formed more and larger clusters. • Optical images show well-distributed nanoparticle ZnO nanorods.

An Experimental and Computational Approach to the Development of ZnO Nanoparticles that are Safe by Design.

Science.gov (United States)

Le, Tu C; Yin, Hong; Chen, Rui; Chen, Yandong; Zhao, Lin; Casey, Philip S; Chen, Chunying; Winkler, David A

2016-07-01

Zinc oxide nanoparticles have found wide application due to their unique optoelectronic and photocatalytic characteristics. However, their safety aspects remain of critical concern, prompting the use of physicochemical modifications of pristine ZnO to reduce any potential toxicity. However, the relationships between these modifications and their effects on biology are complex and still relatively unexplored. To address this knowledge gap, a library of 45 types of ZnO nanoparticles with varying particle size, aspect ratio, doping type, doping concentration, and surface coating is synthesized, and their biological effects measured. Three biological assays measuring cell damage or stress are used to study the responses of human umbilical vein endothelial cells (HUVECs) or human hepatocellular liver carcinoma cells (HepG2) to the nanoparticles. These experimental data are used to develop quantitative and predictive computational models linking nanoparticle properties to cell viability, membrane integrity, and oxidative stress. It is found that the concentration of nanoparticles the cells are exposed to, the type of surface coating, the nature and extent of doping, and the aspect ratio of the particles make significant contributions to the cell toxicity of the nanoparticles tested. Our study shows that it is feasible to generate models that could be used to design or optimize nanoparticles with commercially useful properties that are also safe to humans and the environment. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aqueous chemical route synthesis and the effect of calcination temperature on the structural and optical properties of ZnO nanoparticles

Directory of Open Access Journals (Sweden)

Mohammad Ramzan Parra

2014-10-01

Full Text Available This article reports the controlled size of ZnO nanoparticles synthesized via simple aqueous chemical route without the involvement of any capping agent. The effect of different calcination temperatures on the size of the ZnO nanoparticles was investigated. X-ray diffraction (XRD results indicated that all the samples have crystalline wurtzite phase, and peak broadening analysis was used to evaluate the average crystallite size and lattice strain using Scherrer's equation and Williamson–Hall (W–H method. Morphology and elemental compositions were investigated using atomic force microscopy (AFM and scanning electron microscopy (SEM with energy-dispersive X-ray (EDX spectroscopy. The average crystallite size of ZnO nanoparticles estimated from Scherrer's formula and W–H analysis was found to increase with the increase in calcination temperature. These results were in good agreement with AFM results. Optical properties were investigated using UV–vis spectroscopy in diffused reflectance (DR mode, with a sharp increase in reflectivity at 375 nm and the material has a strong reflective characteristic after 420 nm at 500 °C calcination temperature. Furthermore, photoluminescence spectroscopic results revealed intensive ultraviolet (UV emission with reduced defect concentrations and a slight shifting in band gap energies with increased calcination temperature from 200 °C to 500 °C. This study suggests that the as-prepared ZnO nanoparticles with bandgap tunability might be utilized as window layer in optoelectronic devices.

The optoelectronic properties and role of Cu concentration on the structural and electrical properties of Cu doped ZnO nanoparticles

Science.gov (United States)

Omri, K.; Bettaibi, A.; Khirouni, K.; El Mir, L.

2018-05-01

In the current study, we synthesized a Cu-doped ZnO (CZO) nanoparticles material using a sol-gel method with different doping concentrations of Cu (0, 2, 3 and 4 at.%). The control of the Cu concentration on structural, electrical and optical properties of CZO nanoparticles was investigated in detail. The XRD analysis of the CZO nanoparticles reveals the formation of ZnO hexagonal wurtzite structure for all samples which confirm the incorporation of Cu2+ ions into the ZnO lattice by substitution. Furthermore, CZO nanoparticles showed a small red shift of absorption band with the incorporation of Cu from 0 to 4 at.%; i.e. a decreased band gap value from 3.34 eV to 3.27 eV with increasing of Cu doping content. The frequency dispersion of the electric conductivity were studied using the Jonscher universal power law, according to relation σ(ω) = σDC + A ωs(T). Alternative current conductivity increases with increasing Cu content in spite of the decrease the activation energy with copper loading. It was found that the conductivity reached its maximum value for critical Cu concentration of 3 at.%. The frequency relaxation phenomenon was also investigated and all results were discussed in term of the copper doping concentration.

Tapioca starch: An efficient fuel in gel-combustion synthesis of photocatalytically and anti-microbially active ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ramasami, Alamelu K. [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura (T) (India); Raja Naika, H. [Dept. of Biotechnology, University College of Science, Tumkur University, Tumkur (India); Nagabhushana, H. [CNR Rao Centre for Advanced Materials, Tumkur University, Tumkur (India); Ramakrishnappa, T.; Balakrishna, Geetha R. [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura (T) (India); Nagaraju, G., E-mail: nagarajugn@rediffmail.com [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Kanakapura (T) (India); Dept. of Chemistry, Siddaganga Institute of Technology, Tumkur (India)

2015-01-15

Zinc oxide nanoparticles were synthesized by gel-combustion method using novel bio-fuel tapioca starch pearls, derived from the tubers of Manihotesculenta. The product is characterized using various techniques. The X-ray diffraction pattern correspond to a hexagonal zincite structure. Fourier transform infrared spectrum showed main absorption peaks at 394 and 508 cm{sup −} {sup 1} due to stretching vibration of Zn–O. Ultravoilet–visible spectrum of zinc oxide nanoparticles showed absorption maximum at 373 nm whereas the maximum of the bulk zinc oxide was 377 nm. The morphology of the product was studied using scanning electron microscopy and transmission electron microscopy. The scanning electron microscopic images showed that the products are agglomerated and porous in nature. The transmission electron microscopic images revealed spherical particles of 40–50 nm in diameter. The photocatalytic degradation of methylene blue was examined using zinc oxide nanoparticles and found more efficient in sunlight than ultra-violet light due to reduced band gap. The antibacterial properties of zinc oxide nanoparticles were investigated against four bacterial strains Klebsiella aerogenes, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aereus, where Pseudomonas aeruginosa and Staphylococcus aereus exhibited significant antibacterial activity in agar well diffusion method when compared to positive control. - Highlights: • ZnO nanoparticles have been prepared from a new bio-fuel, tapioca starch by gel combustion method. • XRD pattern revealed hexagonal zincite crystal structure with crystallite size 33 nm. • ZnO nanoparticles exhibited a band gap of 2.70 eV. • The ZnO nanoparticles exhibited superior degradation in sunlight in comparison with UV light. • The product showed a good anti-bacterial activity against two bacterial strains.

Red luminescence from hydrothermally synthesized Eu-doped ZnO ...

Indian Academy of Sciences (India)

Administrator

turally characterized by X-ray diffraction, transmission electron microscopy ... II–VI compound semiconductor with large exciton binding .... ions occupy a site with inversion symmetry and 617 nm ... TEM image of Eu-doped ZnO nanoparticles with (a) 1⋅2 at. .... Jacquier B, Lebrasseur E, Guy S, Belarouci A and Menchini F.

A study on morphology control and optical properties of ZnO nanorods synthesized by microwave heating

International Nuclear Information System (INIS)

Tsai, M.K.; Huang, C.C.; Lee, Y.C.; Yang, C.S.; Yu, H.C.; Lee, J.W.; Hu, S.Y.; Chen, C.H.

2012-01-01

In this study, we present morphology control investigations on zinc oxide (ZnO) nanorods synthesized by microwave heating of a mixture of zinc nitrate hexahydrate and hexamethylenetetramine (HMTA) precursors in deionized water (DI water). To study the morphology and structural variations of the obtained ZnO nanorods in different molar ratio of zinc nitrate hexahydrate to HMTA, X-ray diffraction (XRD), scanning electron microscopy (SEM) images, Raman scattering, and photoluminescence (PL) spectroscopy were measured. XRD and SEM images are utilized to examine the crystalline quality as well as the morphological properties of the ZnO nanorods. It is found that morphology control can be achieved by simply adjusting the reactant concentrations and the molar ratio of zinc nitrate hexahydrate to HMTA. Raman scattering and PL spectroscopy measurements were demonstrated to study the size- and shape-dependent optical response of the ZnO nanorods. The Raman scattering result shows that the intensity of LO mode at around 576 cm -1 decreases with the increase in the molar ratio of zinc nitrate hexahydrate to HMTA, indicating the reduction of defect concentrations in the synthesized ZnO nanorods. Room temperature PL spectrum of the synthesized ZnO nanorods reveals an ultraviolet (UV) emission peak and a broad visible emission. An enhancement of UV emission appears in the PL spectra as the molar ratio of zinc nitrate hexahydrate to HMTA increases, indicating that the defect concentration of the synthesized ZnO nanorods can be reduced by increasing the molar ratio. - Highlights: → Morphology of ZnO nanorods can be controlled via microwave-heating synthesis. → Molar ratio of Zn(NO 3 ) 2 .6H 2 O to C 6 H 12 N 4 affects the aspect ratio of ZnO nanorod. → ZnO nanorod showing higher aspect ratio can exhibit better optical properties.

Spectral features and antibacterial properties of Cu-doped ZnO nanoparticles prepared by sol-gel method

Science.gov (United States)

Alireza, Samavati; A, F. Ismail; Hadi, Nur; Z, Othaman; M, K. Mustafa

2016-07-01

Zn1-x Cu x O (x = 0.00, 0.01, 0.03, and 0.05) nanoparticles are synthesized via the sol-gel technique using gelatin and nitrate precursors. The impact of copper concentration on the structural, optical, and antibacterial properties of these nanoparticles is demonstrated. Powder x-ray diffraction investigations have illustrated the organized Cu doping into ZnO nanoparticles up to Cu concentration of 5% (x = 0.05). However, the peak corresponding to CuO for x = 0.01 is not distinguishable. The images of field emission scanning electron microscopy demonstrate the existence of a nearly spherical shape with a size in the range of 30-52 nm. Doping Cu creates the Cu-O-Zn on the surface and results in a decrease in the crystallite size. Photoluminescence and absorption spectra display that doping Cu causes an increment in the energy band gap. The antibacterial activities of the nanoparticles are examined against Escherichia coli (Gram negative bacteria) cultures using optical density at 600 nm and a comparison of the size of inhibition zone diameter. It is found that both pure and doped ZnO nanoparticles indicate appropriate antibacterial activity which rises with Cu doping. Project supported by the Universiti Teknologi Malaysia (UTM) (Grant No. R. J1300000.7809.4F626). Dr. Samavati is thankful to RMC for postdoctoral grants.

In-situ functionalization of mesoporous hexagonal ZnO synthesized in task specific ionic liquid as a photocatalyst for elimination of SO2, NOx, and CO

Science.gov (United States)

Kowsari, Elaheh; Abdpour, Soheil

2017-12-01

A novel mesoporous structure of zinc oxide was synthesized in hydrothermal autocalve in the presence of a functional ionic liquid (FIL) {[CH2CH2] O2 (mm)2}. This FIL with ether groups was used simultaneously as a designer templating agent and a source of the hydroxyl radical. The presence of this ionic liquid led to producing ethylene glycol in the reaction media, which adsorb on the surface of mesoporous hexagonal ZnO plates. These mesoporous structures can adsorb pollutant gases and increase photocatalytic oxidation of pollutant gases in compare with commercial ZnO nanoparticles and agglomerated nanoparticles synthesized in this work. XPS data confirmed ethylene glycol production by the ionic liquid, which could prove a role for ionic liquids as designers. The estimated BET surface area values of ZnO hexagonal mesoporous plates and agglomerated particles were 84 m2/g and 12 m2/g respectively. Optical properties of the mesoporous structures were analyzed by photoluminescence spectroscopy and diffuse reflectance UV-visible spectroscopy. The performance of these structures as efficient photocatalysts was further demonstrated by their removal of NOx, SO2, and CO under UV irradiation. The removal of NOx, SO2, and CO under UV irradiation was 56%, 81%, and 35% respectively, after 40 min of irradiation time. Reusability of the photocatalyst was determined; the results show no significant decrease of activity of photocatalyst. after five cycles.

Sorption of Th(IV) onto ZnO nanoparticles and diatomite-supported ZnO nanocomposite. Kinetics, mechanism and activation parameters

Energy Technology Data Exchange (ETDEWEB)

Yusan, Sabriye; Aslani, Mahmut A.A.; Aytas, Sule [Ege Univ., Izmir (Turkey). Inst. of Nuclear Sciences; Bampaiti, Anastasia; Noli, Fotini [Aristotle University of Thessaloniki (Greece). Dept. of Chemistry; Erenturk, Sema [Istanbul Technical Univ., Ayazaga Campus, Maslak-Istanbul (Turkey). Energy Inst.

2016-11-01

In this study, for the first time ZnO nanoparticles and diatomite-supported ZnO nanocomposite have been utilized as adsorbent for the removal of Th(IV) ions from aqueous solutions under different experimental conditions. The Langmuir, Freundlich, Temkin and Dubinin- Radushkevich (D-R) isotherms were used to analyze the equilibrium data. The sorption equilibrium data were fitted well to the Langmuir isotherm with maximum sorption capacities values was found to be 1.105 mmol/g and 0.320 mmol/g for ZnO nanoparticles and diatomite supported ZnO nanocomposite, respectively. Pseudo-first and pseudo-second order equations, Intraparticle diffusion and Bangham's models were considered to evaluate the rate parameters and sorption mechanism. Sorption kinetics were better reproduced by the pseudo-second order model (R{sup 2} > 0.999), with an activation energy (E{sub a}) of +99.74 kJ/mol and +62.95 kJ/mol for ZnO nanoparticles and diatomite-supported ZnO nanocomposite, respectively. In order to specify the type of sorption reaction, thermodynamic parameters were also determined. The evaluated ΔG* and ΔH* indicate the non-spontaneous and endothermic nature of the reactions. The results of this work suggest that both of the used materials are fast and effective adsorbents for removing Th(IV) from aqueous solutions and chemical sorption plays a role in controlling the sorption rate.

Gel-combustion-synthesized ZnO nanoparticles for visible light ...

Indian Academy of Sciences (India)

diet in Africa [19], consumed by 500 million people around the world [20] and is ... water splitting by ZnO involves ZnO/Zn redox mechanism where the conversion of .... important tool to study the crystal quality and the vibrations occuring due to ...

Interaction and photodegradation characteristics of fluorescein dye in presence of ZnO nanoparticles.

Science.gov (United States)

Bardhan, Munmun; Mandal, Gopa; Ganguly, Tapan

2011-04-01

The interaction between xanthene dye Fluorescein (Fl) and zinc oxide (ZnO) nanoparticles is investigated under physiological conditions. From the analysis of the steady state and time resolved spectroscopic studies in aqueous solution static mode is found to be responsible in the mechanism of fluorescence quenching of the dye Fl in presence of ZnO. ZnO nanoparticles are used as photocatalyst in order to degrade Fl dye. At pH 7, a maximum degradation efficiency of 44.4% of the dye has been achieved in presence of ZnO as a nanophotocatalyst and the photodegradation follows second-order kinetics.

Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

Directory of Open Access Journals (Sweden)

Jacek Wojnarowicz

2016-05-01

Full Text Available Mn-doped zinc oxide nanoparticles were prepared by using the microwave solvothermal synthesis (MSS technique. The nanoparticles were produced from a solution of zinc acetate dihydrate and manganese(II acetate tetrahydrate using ethylene glycol as solvent. The content of Mn2+ in Zn1−xMnxO ranged from 1 to 25 mol %. The following properties of the nanostructures were investigated: skeleton density, specific surface area (SSA, phase purity (XRD, lattice parameters, dopant content, average particle size, crystallite size distribution, morphology. The average particle size of Zn1−xMnxO was determined using Scherrer’s formula, the Nanopowder XRD Processor Demo web application and by converting the specific surface area results. X-ray diffraction of synthesized samples shows a single-phase wurtzite crystal structure of ZnO without any indication of additional phases. Spherical Zn1−xMnxO particles were obtained with monocrystalline structure and average particle sizes from 17 to 30 nm depending on the content of dopant. SEM images showed an impact of the dopant concentration on the morphology of the nanoparticles.

Characterization of spatial manipulation on ZnO nanocomposites consisting of Au nanoparticles, a graphene layer, and ZnO nanorods

Science.gov (United States)

Huang, Shen-Che; Lu, Chien-Cheng; Su, Wei-Ming; Weng, Chen-Yuan; Chen, Yi-Cian; Wang, Shing-Chung; Lu, Tien-Chang; Chen, Ching-Pang; Chen, Hsiang

2018-01-01

Three types of ZnO-based nanocomposites were fabricated consisting of 80-nm Au nanoparticles (NPs), a graphene layer, and ZnO nanorods (NRs). To investigate interactions between the ZnO NRs and Au nanoparticle, multiple material analysis techniques including field-emission scanning electron microscopy (FESEM), surface contact angle measurements, secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopic characterizations were performed. Results indicate that incorporating a graphene layer could block the interaction between the ZnO NRs and the Au NPs. Furthermore, the Raman signal of the Au NPs could be enhanced by inserting a graphene layer on top of the ZnO NRs. Investigation of these graphene-incorporated nanocomposites would be helpful to future studies of the physical properties and Raman analysis of the ZnO-based nanostructure design.

Water-repellent coatings prepared by modification of ZnO nanoparticles

Science.gov (United States)

Chakradhar, R. P. S.; Dinesh Kumar, V.

Superhydrophobic coatings with a static water contact angle (WCA) > 150° were prepared by modifying ZnO nanoparticles with stearic acid (ZnO@SA). ZnO nanoparticles of size ˜14 nm were prepared by solution combustion method. X-ray diffraction (XRD) studies reveal that as prepared ZnO has hexagonal wurtzite structure whereas the modified coatings convert to zinc stearate. Field emission scanning electron micrographs (FE-SEM) show the dual morphology of the coatings exhibiting both particles and flakes. The flakes are highly fluffy in nature with voids and nanopores. Fourier transformed infrared (FTIR) spectrum shows the stearate ion co-ordinates with Zn2+ in the bidentate form. The surface properties such as surface free energy (γp) and work of adhesion (W) of the unmodified and modified ZnO coatings have been evaluated. The electron paramagnetic resonance (EPR) spectroscopy reveals that surface defects play a major role in the wetting behavior.

Efficiency of Nb-Doped ZnO Nanoparticles Electrode for Dye-Sensitized Solar Cells Application

Science.gov (United States)

Anuntahirunrat, Jirapat; Sung, Youl-Moon; Pooyodying, Pattarapon

2017-09-01

The technological of Dye-sensitized solar cells (DSSCs) had been improved for several years. Due to its simplicity and low cost materials with belonging to the part of thin films solar cells. DSSCs have numerous advantages and benefits among the other types of solar cells. Many of the DSSC devices had use organic chemical that produce by specific method to use as thin film electrodes. The organic chemical that widely use to establish thin film electrodes are Zinc Oxide (ZnO), Titanium Dioxide (TiO2) and many other chemical substances. Zinc oxide (ZnO) nanoparticles had been used in DSSCs applications as thin film electrodes. Nanoparticles are a part of nanomaterials that are defined as a single particles 1-100 nm in diameter. From a few year ZnO widely used in DSSC applications because of its optical, electrical and many others properties. In particular, the unique properties and utility of ZnO structure. However the efficiency of ZnO nanoparticles based solar cells can be improved by doped various foreign impurity to change the structures and properties. Niobium (Nb) had been use as a dopant of metal oxide thin films. Using specification method to doped the ZnO nanoparticles thin film can improved the efficiencies of DSSCs. The efficiencies of Nb-doped ZnO can be compared by doping 0 at wt% to 5 at wt% in ZnO nanoparticles thin films that prepared by the spin coating method. The thin film electrodes doped with 3 at wt% represent a maximum efficiencies with the lowest resistivity of 8.95×10-4 Ω·cm.

Synthesis of ZnO nanorods-Au nanoparticles hybrids via in-situ plasma sputtering-assisted method for simultaneous electrochemical sensing of ascorbic acid and uric acid

Energy Technology Data Exchange (ETDEWEB)

Hou, Chao [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Liu, Hongying, E-mail: liuhongying@hdu.edu.cn [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Dan; Yang, Chi [Department of Pharmacy, Nantong University, Nantong 226001 (China); Zhang, Mingzhen [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China)

2016-05-05

In this study, ZnO nanorods-Au nanoparticles (ZnO NRs-Au NPs) hybrids were prepared using an in-situ plasma sputtering-assisted method without any template. Characterization results from scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy showed that Au NPs are highly dispersed and tightly anchored on the surface of ZnO NRs. The size and surface coverage of Au NPs were well controlled by plasma sputtering time. Moreover, the hybrids exhibited excellent electrocatalytic properties towards oxidation of ascorbic acid (AA) and uric acid (UA) due to large surface area of Au NPs and ZnO NRs, and thus can be used as electrochemical sensors. Differential pulse voltammetry results showed that AA and UA could be detected simultaneously by ZnO NRs-Au NPs hybrids modified glassy carbon electrode. The linear ranges for AA and UA are 0.1 to 4 mM and 0.01 to 0.4 mM, respectively. The results suggest promising future applications in clinical diagnosis. - Highlights: • ZnO nanorods-Au nanoparticles were synthesized by in-situ plasma sputtering method. • Influence of sputtering time on the formation of Au nanoparticles was studied. • It exhibited a strong electrocatalytic activity toward the oxidation of ascorbic acid and uric acid. • A portable and cheap approach for simultaneous detection of ascorbic acid and uric acid was developed.

Synthesis of ZnO nanorods-Au nanoparticles hybrids via in-situ plasma sputtering-assisted method for simultaneous electrochemical sensing of ascorbic acid and uric acid

International Nuclear Information System (INIS)

Hou, Chao; Liu, Hongying; Zhang, Dan; Yang, Chi; Zhang, Mingzhen

2016-01-01

In this study, ZnO nanorods-Au nanoparticles (ZnO NRs-Au NPs) hybrids were prepared using an in-situ plasma sputtering-assisted method without any template. Characterization results from scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy showed that Au NPs are highly dispersed and tightly anchored on the surface of ZnO NRs. The size and surface coverage of Au NPs were well controlled by plasma sputtering time. Moreover, the hybrids exhibited excellent electrocatalytic properties towards oxidation of ascorbic acid (AA) and uric acid (UA) due to large surface area of Au NPs and ZnO NRs, and thus can be used as electrochemical sensors. Differential pulse voltammetry results showed that AA and UA could be detected simultaneously by ZnO NRs-Au NPs hybrids modified glassy carbon electrode. The linear ranges for AA and UA are 0.1 to 4 mM and 0.01 to 0.4 mM, respectively. The results suggest promising future applications in clinical diagnosis. - Highlights: • ZnO nanorods-Au nanoparticles were synthesized by in-situ plasma sputtering method. • Influence of sputtering time on the formation of Au nanoparticles was studied. • It exhibited a strong electrocatalytic activity toward the oxidation of ascorbic acid and uric acid. • A portable and cheap approach for simultaneous detection of ascorbic acid and uric acid was developed.

Investigations of white light emitting europium doped zinc oxide nanoparticles

International Nuclear Information System (INIS)

Ashtaputre, S S; Nojima, A; Marathe, S K; Matsumura, D; Ohta, T; Tiwari, R; Dey, G K; Kulkarni, S K

2008-01-01

Europium doped zinc oxide nanoparticles have been synthesized using a chemical route. The amount of doped europium was varied which shows the changes in the photoluminescence (PL) intensity. The post synthesis annealing effect on the properties of ZnO nanoparticles has also been investigated. In general, PL is broad and a white light is emitted which originates from ZnO and the intra-4f transitions of Eu 3+ ions. The x-ray diffraction patterns do not show any Eu-related peaks for as-synthesized ZnO nanoparticles as well as for annealed samples. X-ray absorption spectroscopy reveals that europium ions are present on the surface of the core of ZnO and inside the shell of zinc hydroxide [Zn(OH 2 )] after annealing

Growth of ZnO nanoparticles from nanowhisker precursor with a simple solvothermal route

International Nuclear Information System (INIS)

Wang Chunlei; Wang Enbo; Shen Enhong; Gao Lei; Kang Zhenhui; Tian Chungui; Zhang Chao; Lan Yang

2006-01-01

Methods of preparing nanoparticles have long been a topic experiencing extensive investigation. Among those methods developed, using template or polymer and surfactant as capping reagents were often effective. However, obtaining nanoparticles in high amounts and high purity still remains an unresolved challenge. Here, a simple two-step solvothermal method without using any surfactant or coating reactant to prepare ZnO nanoparticles with high purity in large scale was developed. X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the as-prepared ZnO nanoparticles, and the formation process of the nanoparticles was discussed finally

Annealing Heat Treatment of ZnO Nanoparticles Grown on Porous Si Substrate Using Spin-Coating Method

Directory of Open Access Journals (Sweden)

K. A. Eswar

2014-01-01

Full Text Available ZnO nanoparticles were successfully deposited on porous silicon (PSi substrate using spin-coating method. In order to prepare PSi, electrochemical etching was employed to modify the Si surface. Zinc acetate dihydrate was used as a starting material in ZnO sol-gel solution preparation. The postannealing treatments were investigated on morphologies and photoluminescence (PL properties of the ZnO thin films. Field emission scanning electron microscopy (FESEM results indicate that the thin films composed by ZnO nanoparticles were distributed uniformly on PSi. The average sizes of ZnO nanoparticle increase with increasing annealing temperature. Atomic force microscopic (AFM analysis reveals that ZnO thin films annealed at 500°C had the smoothest surface. PL spectra show two peaks that completely correspond to nanostructured ZnO and PSi. These findings indicate that the ZnO nanostructures grown on PSi are promising for application as light emitting devices.

Effects of subtoxic concentrations of TiO2 and ZnO nanoparticles on human lymphocytes, dendritic cells and exosome production

International Nuclear Information System (INIS)

Andersson-Willman, Britta; Gehrmann, Ulf; Cansu, Zekiye; Buerki-Thurnherr, Tina; Krug, Harald F.; Gabrielsson, Susanne; Scheynius, Annika

2012-01-01

Metal oxide nanoparticles are widely used in the paint and coating industry as well as in cosmetics, but the knowledge of their possible interactions with the immune system is very limited. Our aims were to investigate if commercially available TiO 2 and ZnO nanoparticles may affect different human immune cells and their production of exosomes, nano-sized vesicles that have a role in cell to cell communication. We found that the TiO 2 or ZnO nanoparticles at concentrations from 1 to 100 μg/mL did not affect the viability of primary human peripheral blood mononuclear cells (PBMC). In contrast, monocyte-derived dendritic cells (MDDC) reacted with a dose dependent increase in cell death and caspase activity to ZnO but not to TiO 2 nanoparticles. Non-toxic exposure, 10 μg/mL, to TiO 2 and ZnO nanoparticles did not significantly alter the phenotype of MDDC. Interestingly, ZnO but not TiO 2 nanoparticles induced a down regulation of FcγRIII (CD16) expression on NK-cells in the PBMC population, suggesting that subtoxic concentrations of ZnO nanoparticles might have an effect on FcγR-mediated immune responses. The phenotype and size of exosomes produced by PBMC or MDDC exposed to the nanoparticles were similar to that of exosomes harvested from control cultures. TiO 2 or ZnO nanoparticles could not be detected within or associated to exosomes as analyzed with TEM. We conclude that TiO 2 and ZnO nanoparticles differently affect immune cells and that evaluations of nanoparticles should be performed even at subtoxic concentrations on different primary human immune cells when investigating potential effects on immune functions. -- Highlights: ► ZnO nanoparticles induce cell death of MDDC but not of PBMC. ► ZnO nanoparticles induce caspase activation and DNA fragmentation in MDDC. ► TiO 2 nanoparticles are taken up by MDDC but have no effect on their phenotype. ► ZnO nanoparticles induce a significant reduction of CD16 expression on NK cells. ► ZnO and TiO 2

Microwave combustion synthesis of hexagonal prism shaped ZnO nanoparticles and effect of Cr on structural, optical and electrical properties of ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Yathisha, R.O. [Department of Chemistry, School of Chemical Sciences, Kuvempu University, Jnanasahyadri, Shankaraghatta 577 451, Karnataka (India); Nayaka, Y. Arthoba, E-mail: drarthoba@yahoo.co.in [Department of Chemistry, School of Chemical Sciences, Kuvempu University, Jnanasahyadri, Shankaraghatta 577 451, Karnataka (India); Vidyasagar, C.C. [Department of Chemistry, School of Basic Sciences, Ranichannamma University, Belgaum 591156, Karnataka (India)

2016-09-15

The synthesis and study of semiconducting nanostructure materials have become a considerable interdisciplinary area of research over the past few decades. The control of morphologies and effective doping by right dopant are the two tasks for the synthesis of semiconducting nanoparticles. The present work outlines the synthesis of ZnO and Cr-ZnO nanoparticles via microwave combustion method without using any fuel. The crystal morphology, optical and electrical properties were characterized by X-ray diffraction study (XRD), UV–Visible spectroscopy (UV–Vis), Scanning electron microscopy (SEM), Energy-dispersive analysis using X-rays (EDAX), Transmission electron microscopy (TEM) and Keithley source meter. The crystal size was determined from XRD, whose values were found to be decreased with increase in the concentration of Cr up to 2 wt% and further increase in the dopant concentration resulted the formation secondary phase (ZnCr{sub 2}O{sub 4}). Scanning electron micrographs shows the hexagonal prism structure of ZnO and Cr-ZnO nanoparticles. EDAX shows the existence of Cr ion in the Cr-ZnO. The optical properties and bandgap studies were undertaken by UV–Visible spectroscopy. I-V characterization study was performed to determine the electrical property of ZnO and Cr-ZnO films. - Highlights: • The prism shaped Zn{sub 1−x}Cr{sub x}O (0 ≤ x ≤ 0.15) was prepared by microwave combustion method. • Effect of Cr on the properties of ZnO was reported. • Change in crystal size was explained by lattice strain and Zener-Pinning effect. • The optical measurements shows up to 8 wt% of Cr doping had more efficient. • Compared to ZnO, Cr doped ZnO enhance the photo voltaic activity.

Synthesis of ZnO nanoparticles for oil-water interfacial tension reduction in enhanced oil recovery

Science.gov (United States)

Soleimani, Hassan; Baig, Mirza Khurram; Yahya, Noorhana; Khodapanah, Leila; Sabet, Maziyar; Demiral, Birol M. R.; Burda, Marek

2018-02-01

Nanoparticles show potential use in applications associated with upstream oil and gas engineering to increase the performance of numerous methods such as wettability alteration, interfacial tension reduction, thermal conductivity and enhanced oil recovery operations. Surface tension optimization is an important parameter in enhanced oil recovery. Current work focuses on the new economical method of surface tension optimization of ZnO nanofluids for oil-water interfacial tension reduction in enhanced oil recovery. In this paper, zinc oxide (ZnO) nanocrystallites were prepared using the chemical route and explored for enhanced oil recovery (EOR). Adsorption of ZnO nanoparticles (NPs) on calcite (111) surface was investigated using the adsorption locator module of Materials Studio software. It was found that ZnO nanoparticles show maximum adsorption energy of - 253 kcal/mol. The adsorption of ZnO on the rock surface changes the wettability which results in capillary force reduction and consequently increasing EOR. The nanofluids have been prepared by varying the concentration of ZnO nanoparticles to find the optimum value for surface tension. The surface tension (ST) was calculated with different concentration of ZnO nanoparticles using the pendant drop method. The results show a maximum value of ST 35.57 mN/m at 0.3 wt% of ZnO NPs. It was found that the nanofluid with highest surface tension (0.3 wt%) resulted in higher recovery efficiency. The highest recovery factor of 11.82% at 0.3 wt% is due to the oil/water interfacial tension reduction and wettability alteration.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

International Nuclear Information System (INIS)

Matinise, N.; Fuku, X.G.; Kaviyarasu, K.; Mayedwa, N.; Maaza, M.

2017-01-01

Highlights: • Biosynthesis of ZnO nanoparticlesl by green process using Moringa Oliefera extract. • Electrochemical studies were confirmed by cyclic and Square wave voltammetry. • XRD, HRTEM, TGA/DSC, FTIR were used to characterized the nanoparticles. - Abstract: The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV–vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

Energy Technology Data Exchange (ETDEWEB)

Matinise, N., E-mail: nmatinise@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Fuku, X.G., E-mail: fuku@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Kaviyarasu, K., E-mail: kasinathankariyarasu@gmail.com [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Mayedwa, N., E-mail: nmyedi@gmail.com [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Maaza, M., E-mail: maaza@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa)

2017-06-01

Highlights: • Biosynthesis of ZnO nanoparticlesl by green process using Moringa Oliefera extract. • Electrochemical studies were confirmed by cyclic and Square wave voltammetry. • XRD, HRTEM, TGA/DSC, FTIR were used to characterized the nanoparticles. - Abstract: The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV–vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

Photocatalytic properties of hierarchical ZnO flowers synthesized by a sucrose-assisted hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Lv Wei [Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China); Wei Bo [Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin 150080 (China); Xu Lingling, E-mail: xulingling_hit@163.com [Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China) and Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin 150080 (China); Zhao Yan, E-mail: zhaoyan516@126.com [Department of Physics, Northeast Forestry University, Harbin 150040 (China); Gao Hong; Liu Jia [Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. Black-Right-Pointing-Pointer The sucrose added ZnO flowers showed improved activity mainly due to the improved crystallinity. Black-Right-Pointing-Pointer The effect of sucrose content was studied and optimized. - Abstract: In this work, hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. The thermogravimetric analysis/differential thermal analysis (TGA-DTA) and Fourier transform infrared spectra (FTIR) showed that sucrose acted as a complexing agent in the synthesis process and assisted combustion during annealing. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. The sucrose added ZnO flowers showed improved activity, which was mainly attributed to the better crystallinity as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The effect of sucrose amount on photocatalytic activity was also studied.

Studies on intrinsic defects related to Zn vacancy in ZnO nanoparticles

International Nuclear Information System (INIS)

Singh, V.P.; Das, D.; Rath, Chandana

2013-01-01

Graphical abstract: Display Omitted Highlights: ► Williamson–Hall analysis of ZnO indicates strain in the lattice and size is of 20 nm. ► PL shows a broad emission peak in visible range due to native defects. ► Raman active modes corresponding to P6 3 mc and a few additional modes are observed. ► FTIR detects few local vibrational modes of hydrogen attached to zinc vacancies. ► V Zn -H and Zn + O divacancies are confirmed by PAS. -- Abstract: ZnO being a well known optoelectronic semiconductor, investigations related to the defects are very promising. In this report, we have attempted to detect the defects in ZnO nanoparticles synthesized by the conventional coprecipitation route using various spectroscopic techniques. The broad emission peak observed in photoluminescence spectrum and the non zero slope in Williamson–Hall analysis indicate the defects induced strain in the ZnO lattice. A few additional modes observed in Raman spectrum could be due to the breakdown of the translation symmetry of the lattice caused by defects and/or impurities. The presence of impurities can be ruled out as XRD pattern shows pure wurtzite structure. The presence of the vibrational band related to the Zn vacancies (V Zn ), unintentional hydrogen dopants and their complex defects confirm the defects in ZnO lattice. Positron life time components τ 1 and τ 2 additionally support V Zn attached to hydrogen and to a cluster of Zn and O di-vacancies respectively.

Synthesis and characterization of nanocomposites ZnO / polypyrrole for anti corrosive application

International Nuclear Information System (INIS)

Valenca, D.P.; Bouchonneau, N.; Vieira, M.R.S.; Alves, K.G.B.; Melo, C.P. de; Urtiga Filho, S.L.

2014-01-01

Nanoparticles of metal oxides and conductive polymers have been investigated as alternative additives in corrosion protection of oxidizable metals. In this hybrid nanocomposites work Polypyrrole-ZnO were synthesized and characterized as a potential application as industrial paint anti corrosive additive. The different steps of the synthesis and characterization of nanocomposites are described. The nanocomposites were obtained from the emulsion polymerization of aqueous solutions of pyrrole and sodium dodecyl sulfate containing ZnO nanoparticles dispersed in the mass. The nanoparticles were characterized by scanning electron microscopy and transmission, dynamic light scattering, diffraction of X-rays and techniques of infrared spectroscopy. From the characterization techniques, it was possible to determine the average size of nanoparticles of ZnO and ZnO-Polypyrrole. The peaks in the diffraction pattern of X-rays observed in the nanocomposite were the same as in ZnO, confirming the presence of ZnO in the composite. (author)

Electrical and structural properties of ZnO synthesized via infiltration of lithographically defined polymer templates

International Nuclear Information System (INIS)

Nam, Chang-Yong; Stein, Aaron; Kisslinger, Kim; Black, Charles T.

2015-01-01

We investigate the electrical and structural properties of infiltration-synthesized ZnO. In-plane ZnO nanowire arrays with prescribed positional registrations are generated by infiltrating diethlyzinc and water vapor into lithographically defined SU-8 polymer templates and removing organic matrix by oxygen plasma ashing. Transmission electron microscopy reveals that homogeneously amorphous as-infiltrated polymer templates transform into highly nanocrystalline ZnO upon removal of organic matrix. Field-effect transistor device measurements show that the synthesized ZnO after thermal annealing displays a typical n-type behavior, ∼10 19  cm −3 carrier density, and ∼0.1 cm 2 V −1 s −1 electron mobility, reflecting highly nanocrystalline internal structure. The results demonstrate the potential application of infiltration synthesis in fabricating metal oxide electronic devices

Synthesis and characterization of Mn-doped ZnO diluted magnetic semiconductors

Energy Technology Data Exchange (ETDEWEB)

Abdel-Galil, A. [Solid State Physics and Accelerators Department, NCRRT, Atomic Energy Authority, Cairo (Egypt); Balboul, M.R., E-mail: m_balboul@yahoo.com [Solid State Physics and Accelerators Department, NCRRT, Atomic Energy Authority, Cairo (Egypt); Sharaf, A. [Radiation Engineering Department, NCRRT, Atomic Energy Authority, Cairo (Egypt)

2015-11-15

In the present work undoped and Mn doped ZnO nanoparticles (ZnO:Mn), diluted magnetic semiconductors, were successfully synthesized by the sol–gel method at room temperature. The morphology of ZnO nanoparticles constituted by flower-like structures with hexagonal morphologies that changed significantly after the incorporation of Mn. Rietveld refinements results showed that Mn ions are successfully doped into ZnO matrix without altering its wurtzite phase. Meanwhile, Raman spectroscopy analyses confirm the wurtzite structure of undoped ZnO and ZnO:Mn nanoparticles. The lattice parameters increase with increasing Mn content due to the large ionic radius of Mn{sup 2+} compared to that of Zn{sup 2+}. Electron spin resonance measurements were performed to gain information about oxidation state and site occupancy of the magnetic Mn ions in the ZnO lattice. Moreover, UV–vis absorption spectra have been utilized to calculate the optical band gap of the undoped ZnO and ZnO:Mn nanoparticles before and after different γ-irradiation doses. The band gap of ZnO:Mn (2%) is 2.62 eV which is noticeably smaller than the 3.26 eV of undoped ZnO. The thermal decomposition properties of the prepared nanoparticle samples were also studied using simultaneous Thermogravimetric analysis in temperature range from 30 to 500 °C.

Synthesis and Characterization of Antireflective ZnO Nanoparticles Coatings Used for Energy Improving Efficiency of Silicone Solar Cells

Science.gov (United States)

Pîslaru-Dǎnescu, Lucian; Chitanu, Elena; El-Leathey, Lucia-Andreea; Marinescu, Virgil; Marin, Dorian; Sbârcea, Beatrice-Gabriela

2018-03-01

The paper proposes a new and complex process for the synthesis of ZnO nanoparticles for antireflective coating corresponding to silicone solar cells applications. The process consists of two major steps: preparation of seed layer and hydrothermal growth of ZnO nanoparticles. Due to the fact that the seed layer morphology influences the ZnO nanoparticles proprieties, the process optimization of the seed layer preparation is necessary. Following the hydrothermal growth of the ZnO nanoparticles, antireflective coating of silicone solar cells is achieved. After determining the functional parameters of the solar cells provided either with glass or with ZnO, it is concluded that all the parameters values are superior in the case of solar cells with ZnO antireflection coating and are increasing along with the solar irradiance.

Enhancement in visible light-responsive photocatalytic activity by embedding Cu-doped ZnO nanoparticles on multi-walled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Ahmad, M., E-mail: mzkhm73@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ahmed, E., E-mail: profejaz@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Hong, Z.L.; Jiao, X.L. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Abbas, T. [Institute of Industrial Control System, Rawalpindi (Pakistan); Khalid, N.R. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

2013-11-15

Copper doped ZnO nanoparticles embedded on multi-walled carbon nanotubes (CNTs) were successfully synthesized using a facile, nontoxic sol method. The resulting visible light-responsive Cu-doped ZnO/CNTs composites were characterized using powder X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), transmission electron microscope (TEM), scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and Brunauer Emmett Teller (BET) surface area analyzer. Optical properties of Cu-doped ZnO/CNTs nanocomposites, studied using UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy (PL), which exhibited extended light absorption in visible light region and possessed better charge separation capability, respectively as compared to Cu-doped ZnO, pure ZnO and ZnO/CNTs composite. The photocatalytic activity was tested by degradation of methyl orange (MO) dye under visible light irradiation. The results demonstrated that Cu-doped ZnO/CNTs nanocomposites effectively bleached out MO, showing an impressive photocatalytic enhancement over ZnO, commercial ZnO, Cu-doped ZnO nanoparticles and ZnO/CNTs nanocomposites. Chemical oxygen demand (COD) of textile wastewater was also measured before and after the photocatalysis experiment under sunlight to evaluate the mineralization of wastewater. The significant decrease in COD of the treated effluent revealed a complete destruction of the organic molecules along with color removal. This dramatically enhanced photoactivity of nanocomposite photocatalysts was attributed to greater adsorptivity of dyes, extended light absorption and increased charge separation efficiency due to excellent electrical properties of carbon nanotubes and the large surface area.

Synthesis and characterization of Mg-doped ZnO hollow spheres

International Nuclear Information System (INIS)

Hammad, Talaat M.; Salem, Jamil K.

2011-01-01

Mg-doped ZnO nanoparticles were synthesized by a simple chemical method at low temperature with Mg:Zn atomic ratio from 0 to 7%. The synthesis process is based on the hydrolysis of zinc acetate dihydrate and magnesium acetate tetrahydrate were heated under refluxing at 65 °C using methanol as a solvent. X-ray diffraction analysis reveals that the Mg-doped ZnO crystallizes in a wurtzite structure with crystal size of 5–12 nm. These nanocrystals self-aggregated themselves into hollow spheres of size of 800–1100 nm. High resolution transmission electron microscopy images show that each sphere is made up of numerous nanoparticles of average diameter 5–11 nm. The XRD patterns, SEM and TEM micrographs of doping of Mg in ZnO confirmed the formation of hollow spheres indicating that the Mg 2+ is successfully substituted into the ZnO host structure of the Zn 2+ site. Furthermore, the UV–Vis spectra and photoluminescence (PL) spectra of the ZnO nanoparticles were also investigated. The band gap of the nanoparticles can be tuned in the range of 3.36–3.55 eV by the use of the dopants.

Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles

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Vitaliy Shvalagin

2016-01-01

Full Text Available For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

In situ formation deposited ZnO nanoparticles on silk fabrics under ultrasound irradiation.

Science.gov (United States)

Khanjani, Somayeh; Morsali, Ali; Joo, Sang W

2013-03-01

Deposition of zinc(II) oxide (ZnO) nanoparticles on the surface of silk fabrics was prepared by sequential dipping steps in alternating bath of potassium hydroxide and zinc nitrate under ultrasound irradiation. This coating involves in situ generation and deposition of ZnO in a one step. The effects of ultrasound irradiation, concentration and sequential dipping steps on growth of the ZnO nanoparticles have been studied. Results show a decrease in the particles size as increasing power of ultrasound irradiation. Also, increasing of the concentration and sequential dipping steps increase particle size. The physicochemical properties of the nanoparticles were determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX). Copyright © 2012 Elsevier B.V. All rights reserved.

Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

Science.gov (United States)

Gwak, Gyeong-Hyeon; Lee, Won-Jae; Paek, Seung-Min; Oh, Jae-Min

2015-03-01

We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization. The pH values of the aqueous ZnO colloids at each condition were in the neutral to slightly basic range and showed different patterns depending on the original size and surface chemistry of the ZnO nanoparticles. The gastric pH condition was found to significantly dissolve ZnO nanoparticles up to 18-30 wt%, while the intestinal or plasma pH conditions resulted in much lower dissolution amounts than expected. Based on the X-ray diffraction patterns and X-ray absorption spectra, we identified partial phase transition of the ZnO nanoparticles from wurtzite to Zn(OH)2 under the intestinal and plasma pH conditions. Using scanning electron microscopy, we verified that the overall particle size and morphology of all ZnO nanoparticles were maintained regardless of the pH. Copyright © 2015 Elsevier B.V. All rights reserved.

Preferential killing of cancer cells and activated human T cells using ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hanley, Cory; Layne, Janet; Feris, Kevin; Wingett, Denise [Department of Biological Sciences, Boise State University, Boise, ID 83725 (United States); Punnoose, Alex; Reddy, K M; Coombs, Isaac; Coombs, Andrew [Department of Physics, Boise State University, Boise, ID 83725 (United States)], E-mail: denisewingett@boisestate.edu

2008-07-23

Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine. Here we examine the response of normal human cells to ZnO nanoparticles under different signaling environments and compare it to the response of cancerous cells. ZnO nanoparticles exhibit a strong preferential ability to kill cancerous T cells ({approx}28-35 x) compared to normal cells. Interestingly, the activation state of the cell contributes toward nanoparticle toxicity, as resting T cells display a relative resistance while cells stimulated through the T cell receptor and CD28 costimulatory pathway show greater toxicity in direct relation to the level of activation. Mechanisms of toxicity appear to involve the generation of reactive oxygen species, with cancerous T cells producing higher inducible levels than normal T cells. In addition, nanoparticles were found to induce apoptosis and the inhibition of reactive oxygen species was found to be protective against nanoparticle induced cell death. The novel findings of cell selective toxicity, towards potential disease causing cells, indicate a potential utility of ZnO nanoparticles in the treatment of cancer and/or autoimmunity.

Preferential killing of cancer cells and activated human T cells using ZnO nanoparticles

International Nuclear Information System (INIS)

Hanley, Cory; Layne, Janet; Feris, Kevin; Wingett, Denise; Punnoose, Alex; Reddy, K M; Coombs, Isaac; Coombs, Andrew

2008-01-01

Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine. Here we examine the response of normal human cells to ZnO nanoparticles under different signaling environments and compare it to the response of cancerous cells. ZnO nanoparticles exhibit a strong preferential ability to kill cancerous T cells (∼28-35 x) compared to normal cells. Interestingly, the activation state of the cell contributes toward nanoparticle toxicity, as resting T cells display a relative resistance while cells stimulated through the T cell receptor and CD28 costimulatory pathway show greater toxicity in direct relation to the level of activation. Mechanisms of toxicity appear to involve the generation of reactive oxygen species, with cancerous T cells producing higher inducible levels than normal T cells. In addition, nanoparticles were found to induce apoptosis and the inhibition of reactive oxygen species was found to be protective against nanoparticle induced cell death. The novel findings of cell selective toxicity, towards potential disease causing cells, indicate a potential utility of ZnO nanoparticles in the treatment of cancer and/or autoimmunity

Morphology and Structure of ZnO Nanoparticles Produced by Electrochemical Method

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Barbara STYPUŁA

2014-04-01

Full Text Available This article presents studies of the morphology and structure of ZnO nanoparticles synthesized by the electrochemical method. Colloidal solutions of the nanoparticles are obtained by an anodic dissolution of metallic zinc in alcohol solutions of lithium chloride containing a small amount of water (5 % vol.. The parameters chosen for the synthesis are based on Zn polarization curves(obtained using the the potentiokinetic (Linear Sweep Voltammetry – LSV and the chronoamperometric method. The synthesis of zinc oxide nanoparticles is carried out in 0.05m LiCl + 5 % H2O alcohol (methanol or propanol solutions during galvanostatic polarization of Zn at 3 mA/cm2 current density. The process is performed in a two-electrode system, where both electrodes (the working anode and cathode are made of zinc. Optical properties, morphology and structure of the colloidal solutions and powders (obtained after evaporating the solvent were studied using the following spectroscopic and microscopic techniques: UltraViolet and Visible Spectroscopy (UV-VIS, Fourier Transform Infrared Spectroscopy (FTIR, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM.DOI: http://dx.doi.org/10.5755/j01.ms.20.1.4417

Reducing ZnO nanoparticles toxicity through silica coating

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Sing Ling Chia

2016-10-01

Full Text Available ZnO NPs have good antimicrobial activity that can be utilized as agents to prevent harmful microorganism growth in food. However, the use of ZnO NPs as food additive is limited by the perceived high toxicity of ZnO NPs in many earlier toxicity studies. In this study, surface modification by silica coating was used to reduce the toxicity of ZnO NPs by significantly reducing the dissolution of the core ZnO NPs. To more accurately recapitulate the scenario of ingested ZnO NPs, we tested our as synthesized ZnO NPs in ingestion fluids (synthetic saliva and synthetic gastric juice to determine the possible forms of ZnO NPs in digestive system before exposing the products to colorectal cell lines. The results showed that silica coating is highly effective in reducing toxicity of ZnO NPs through prevention of the dissociation of ZnO NPs to zinc ions in both neutral and acidic condition. The silica coating however did not alter the desired antimicrobial activity of ZnO NPs to E. coli and S. aureus. Thus, silica coating offered a potential solution to improve the biocompatibility of ZnO NPs for applications such as antimicrobial agent in foods or food related products like food packaging. Nevertheless, caution remains that high concentration of silica coated ZnO NPs can still induce undesirable cytotoxicity to mammalian gut cells. This study indicated that upstream safer-by-design philosophy in nanotechnology can be very helpful in a product development.

Eosin-Y sensitized core-shell TiO2-ZnO nano-structured photoanodes for dye-sensitized solar cell applications.

Science.gov (United States)

Manikandan, V S; Palai, Akshaya K; Mohanty, Smita; Nayak, Sanjay K

2018-06-01

In the current investigation, TiO 2 and TiO 2 -ZnO (core-shell) spherical nanoparticles were synthesized by simple combined hydrolysis and refluxing method. A TiO 2 core nanomaterial on the shell material of ZnO was synthesized by utilizing variable ratios of ZnO. The structural characterization of TiO 2 -ZnO core/shell nanoparticles were done by XRD analysis. The spherical structured morphology of the TiO 2 -ZnO has been confirmed through field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) studies. The UV-visible spectra of TiO 2 -ZnO nanostructures were also compared with the pristine TiO 2 to investigate the shift of wavelength. The TiO 2 -ZnO core/shell nanoparticles at the interface efficiently collect the photogenarated electrons from ZnO and also ZnO act a barrier for reduced charge recombination of electrolyte and dye-nanoparticles interface. This combination improved the light absorption which induced the charge transfer ability and dye loading capacity of core-shell nanoparticles. An enhancement in the short circuit current (J sc ) from 1.67 mA/cm 2 to 2.1 mA/cm 2 has been observed for TiO 2 -ZnObased photoanode (with platinum free counter electrode), promises an improvement in the energy conversion efficiency by 57% in comparison with that of the DSSCs based on the pristine TiO 2 . Henceforth, TiO 2 -ZnO photoelectrode in ZnO will effectively act as barrier at the interface of TiO 2 -ZnO and TiO 2 , ensuring the potential for DSSC application. Copyright © 2018 Elsevier B.V. All rights reserved.

Aluminum doping tunes band gap energy level as well as oxidative stress-mediated cytotoxicity of ZnO nanoparticles in MCF-7 cells

Science.gov (United States)

Akhtar, Mohd Javed; Alhadlaq, Hisham A.; Alshamsan, Aws; Majeed Khan, M. A.; Ahamed, Maqusood

2015-09-01

We investigated whether Aluminum (Al) doping tunes band gap energy level as well as selective cytotoxicity of ZnO nanoparticles in human breast cancer cells (MCF-7). Pure and Al-doped ZnO nanoparticles were prepared by a simple sol-gel method. Characterization study confirmed the formation of single phase of AlxZn1-xO nanocrystals with the size range of 33-55 nm. Al-doping increased the band gap energy of ZnO nanoparticles (from 3.51 eV for pure to 3.87 eV for Al-doped ZnO). Al-doping also enhanced the cytotoxicity and oxidative stress response of ZnO nanoparticles in MCF-7 cells. The IC50 for undoped ZnO nanoparticles was 44 μg/ml while for the Al-doped ZnO counterparts was 31 μg/ml. Up-regulation of apoptotic genes (e.g. p53, bax/bcl2 ratio, caspase-3 & caspase-9) along with loss of mitochondrial membrane potential suggested that Al-doped ZnO nanoparticles induced apoptosis in MCF-7 cells through mitochondrial pathway. Importantly, Al-doping did not change the benign nature of ZnO nanoparticles towards normal cells suggesting that Al-doping improves the selective cytotoxicity of ZnO nanoparticles toward MCF-7 cells without affecting the normal cells. Our results indicated a novel approach through which the inherent selective cytotoxicity of ZnO nanoparticles against cancer cells can be further improved.

ZnO Nanoparticles Affect Bacillus subtilis Cell Growth and Biofilm Formation.

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Yi-Huang Hsueh

Full Text Available Zinc oxide nanoparticles (ZnO NPs are an important antimicrobial additive in many industrial applications. However, mass-produced ZnO NPs are ultimately disposed of in the environment, which can threaten soil-dwelling microorganisms that play important roles in biodegradation, nutrient recycling, plant protection, and ecological balance. This study sought to understand how ZnO NPs affect Bacillus subtilis, a plant-beneficial bacterium ubiquitously found in soil. The impact of ZnO NPs on B. subtilis growth, FtsZ ring formation, cytosolic protein activity, and biofilm formation were assessed, and our results show that B. subtilis growth is inhibited by high concentrations of ZnO NPs (≥ 50 ppm, with cells exhibiting a prolonged lag phase and delayed medial FtsZ ring formation. RedoxSensor and Phag-GFP fluorescence data further show that at ZnO-NP concentrations above 50 ppm, B. subtilis reductase activity, membrane stability, and protein expression all decrease. SDS-PAGE Stains-All staining results and FT-IR data further demonstrate that ZnO NPs negatively affect exopolysaccharide production. Moreover, it was found that B. subtilis biofilm surface structures became smooth under ZnO-NP concentrations of only 5-10 ppm, with concentrations ≤ 25 ppm significantly reducing biofilm formation activity. XANES and EXAFS spectra analysis further confirmed the presence of ZnO in co-cultured B. subtilis cells, which suggests penetration of cell membranes by either ZnO NPs or toxic Zn+ ions from ionized ZnO NPs, the latter of which may be deionized to ZnO within bacterial cells. Together, these results demonstrate that ZnO NPs can affect B. subtilis viability through the inhibition of cell growth, cytosolic protein expression, and biofilm formation, and suggest that future ZnO-NP waste management strategies would do well to mitigate the potential environmental impact engendered by the disposal of these nanoparticles.

Methodology for sample preparation and size measurement of commercial ZnO nanoparticles

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Pei-Jia Lu

2018-04-01

Full Text Available This study discusses the strategies on sample preparation to acquire images with sufficient quality for size characterization by scanning electron microscope (SEM using two commercial ZnO nanoparticles of different surface properties as a demonstration. The central idea is that micrometer sized aggregates of ZnO in powdered forms need to firstly be broken down to nanosized particles through an appropriate process to generate nanoparticle dispersion before being deposited on a flat surface for SEM observation. Analytical tools such as contact angle, dynamic light scattering and zeta potential have been utilized to optimize the procedure for sample preparation and to check the quality of the results. Meanwhile, measurements of zeta potential values on flat surfaces also provide critical information and save lots of time and efforts in selection of suitable substrate for particles of different properties to be attracted and kept on the surface without further aggregation. This simple, low-cost methodology can be generally applied on size characterization of commercial ZnO nanoparticles with limited information from vendors. Keywords: Zinc oxide, Nanoparticles, Methodology

ZnO nanoparticle as catalyst for efficient green one-pot synthesis of ...

Indian Academy of Sciences (India)

The zinc oxide (ZnO) nanoparticles functions as highly effective catalyst for the reactions of various o-hydroxy ... the synthesis of relatively large and complex molecules .... of ethylene diamine in hydrothermal ZnO nanorod syn- thesis. Di- and ...

Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

Science.gov (United States)

Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu

2014-01-01

The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H2 in Ar ambient at 700 °C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between "on" and "off" states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (VZn + OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, VZn + OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57 μB. The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism.

Solid-state dye-sensitized solar cells based on ZnO nanoparticle and nanorod array hybrid photoanodes

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Sue Hung-Jue

2011-01-01

Full Text Available Abstract The effect of ZnO photoanode morphology on the performance of solid-state dye-sensitized solar cells (DSSCs is reported. Four different structures of dye-loaded ZnO layers have been fabricated in conjunction with poly(3-hexylthiophene. A significant improvement in device efficiency with ZnO nanorod arrays as photoanodes has been achieved by filling the interstitial voids of the nanorod arrays with ZnO nanoparticles. The overall power conversion efficiency increases from 0.13% for a nanorod-only device to 0.34% for a device with combined nanoparticles and nanorod arrays. The higher device efficiency in solid-state DSSCs with hybrid nanorod/nanoparticle photoanodes is originated from both large surface area provided by nanoparticles for dye adsorption and efficient charge transport provided by the nanorod arrays to reduce the recombinations of photogenerated carriers.

Development of Multi-functional Properties on Cotton Fabric by In Situ Application of TiO2 and ZnO Nanoparticles

Science.gov (United States)

Butola, B. S.; Garg, Aayush; Garg, Aman; Chauhan, Indu

2018-06-01

Cotton fabrics functionalized with different combinations of TiO2 and ZnO were evaluated for multifunctional properties including UV protection, antimicrobial and self-cleaning. The ZnO nanoparticles synthesized using sol gel method were applied on cotton fabric by pad-dry-cure method and TiO2 was deposited in situ. The deposition of both TiO2 and ZnO was examined and confirmed by SEM and EDX analysis. Application of both metal oxides resulted in good improvement in UV protection of treated fabrics. The fabrics which were finished with combination of both Zinc and Titanium oxides, showed UPF rating of 50+ as compared to UPF rating of untreated cotton, which was only 5. The same fabrics also showed higher self-cleaning extent as compared to untreated cotton fabric. It was found that the sequence of application of ZnO and TiO2 affected the antimicrobial activity of the finished fabric and also the durability. When application of TiO2 was followed by ZnO, the combination resulted in development of excellent antimicrobial property against Escherichia coli ( 99% colony reduction) which was retained after 10 wash cycles. However, when application of ZnO nanoparticles was followed by application of TiO2, the improvement in antimicrobial activity was found to be moderate ( 48% colony reduction) and had poor wash durability. Hence, the specific sequence of application of these metals oxides can be utilized for obtaining good durability of the multifunctional properties on cotton fabric.

Development of Multi-functional Properties on Cotton Fabric by In Situ Application of TiO2 and ZnO Nanoparticles

Science.gov (United States)

Butola, B. S.; Garg, Aayush; Garg, Aman; Chauhan, Indu

2018-05-01

Cotton fabrics functionalized with different combinations of TiO2 and ZnO were evaluated for multifunctional properties including UV protection, antimicrobial and self-cleaning. The ZnO nanoparticles synthesized using sol gel method were applied on cotton fabric by pad-dry-cure method and TiO2 was deposited in situ. The deposition of both TiO2 and ZnO was examined and confirmed by SEM and EDX analysis. Application of both metal oxides resulted in good improvement in UV protection of treated fabrics. The fabrics which were finished with combination of both Zinc and Titanium oxides, showed UPF rating of 50+ as compared to UPF rating of untreated cotton, which was only 5. The same fabrics also showed higher self-cleaning extent as compared to untreated cotton fabric. It was found that the sequence of application of ZnO and TiO2 affected the antimicrobial activity of the finished fabric and also the durability. When application of TiO2 was followed by ZnO, the combination resulted in development of excellent antimicrobial property against Escherichia coli ( 99% colony reduction) which was retained after 10 wash cycles. However, when application of ZnO nanoparticles was followed by application of TiO2, the improvement in antimicrobial activity was found to be moderate ( 48% colony reduction) and had poor wash durability. Hence, the specific sequence of application of these metals oxides can be utilized for obtaining good durability of the multifunctional properties on cotton fabric.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

Science.gov (United States)

Matinise, N.; Fuku, X. G.; Kaviyarasu, K.; Mayedwa, N.; Maaza, M.

2017-06-01

The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV-vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

Effects of subtoxic concentrations of TiO{sub 2} and ZnO nanoparticles on human lymphocytes, dendritic cells and exosome production

Energy Technology Data Exchange (ETDEWEB)

Andersson-Willman, Britta; Gehrmann, Ulf; Cansu, Zekiye [Translational Immunology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm (Sweden); Buerki-Thurnherr, Tina; Krug, Harald F. [Laboratory for Materials — Biology Interactions, Swiss Federal Laboratories of Materials Testing and Research, St. Gallen (Switzerland); Gabrielsson, Susanne [Translational Immunology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm (Sweden); Scheynius, Annika, E-mail: annika.scheynius@ki.se [Translational Immunology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm (Sweden)

2012-10-01

Metal oxide nanoparticles are widely used in the paint and coating industry as well as in cosmetics, but the knowledge of their possible interactions with the immune system is very limited. Our aims were to investigate if commercially available TiO{sub 2} and ZnO nanoparticles may affect different human immune cells and their production of exosomes, nano-sized vesicles that have a role in cell to cell communication. We found that the TiO{sub 2} or ZnO nanoparticles at concentrations from 1 to 100 μg/mL did not affect the viability of primary human peripheral blood mononuclear cells (PBMC). In contrast, monocyte-derived dendritic cells (MDDC) reacted with a dose dependent increase in cell death and caspase activity to ZnO but not to TiO{sub 2} nanoparticles. Non-toxic exposure, 10 μg/mL, to TiO{sub 2} and ZnO nanoparticles did not significantly alter the phenotype of MDDC. Interestingly, ZnO but not TiO{sub 2} nanoparticles induced a down regulation of FcγRIII (CD16) expression on NK-cells in the PBMC population, suggesting that subtoxic concentrations of ZnO nanoparticles might have an effect on FcγR-mediated immune responses. The phenotype and size of exosomes produced by PBMC or MDDC exposed to the nanoparticles were similar to that of exosomes harvested from control cultures. TiO{sub 2} or ZnO nanoparticles could not be detected within or associated to exosomes as analyzed with TEM. We conclude that TiO{sub 2} and ZnO nanoparticles differently affect immune cells and that evaluations of nanoparticles should be performed even at subtoxic concentrations on different primary human immune cells when investigating potential effects on immune functions. -- Highlights: ► ZnO nanoparticles induce cell death of MDDC but not of PBMC. ► ZnO nanoparticles induce caspase activation and DNA fragmentation in MDDC. ► TiO{sub 2} nanoparticles are taken up by MDDC but have no effect on their phenotype. ► ZnO nanoparticles induce a significant reduction of CD16

Maple leaf (Acer sp.) extract mediated green process for the functionalization of ZnO powders with silver nanoparticles.

Science.gov (United States)

Vivekanandhan, Singaravelu; Schreiber, Makoto; Mason, Cynthia; Mohanty, Amar Kumar; Misra, Manjusri

2014-01-01

The functionalization of ZnO powders with silver nanoparticles (AgNPs) through a novel maple leaf extract mediated biological process was demonstrated. Maple leaf extract was found to be a very effective bioreduction agent for the reduction of silver ions. The reduction rate of Ag(+) into Ag(0) was found to be much faster than other previously reported bioreduction rates and was comparable to the reduction rates obtained through chemical means. The functionalization of ZnO particles with silver nanoparticles through maple leaf extract mediated bioreduction of silver was investigated through UV-visible spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction analysis. It was found that the ZnO particles were coated with silver nanoparticles 5-20 nm in diameter. The photocatalytic ability of the ZnO particles functionalized with silver nanoparticles was found to be significantly improved compared to the photocatalytic ability of the neat ZnO particles. The silver functionalized ZnO particles reached 90% degradation of the dye an hour before the neat ZnO particles. Copyright © 2013 Elsevier B.V. All rights reserved.

Nanoscaled Electrocatalytic Optically Modulated ZnO Nanoparticles through Green Process of Punica granatum L. and Their Antibacterial Activities

Directory of Open Access Journals (Sweden)

Xolile Fuku

2016-01-01

Full Text Available Most recently, green synthesis of metal oxide nanoparticles has become an interesting subject of the nanoscience and nanotechnology. The use of plant systems has been deemed a green route and a dependable method for nanoparticle biosynthesis, owing to its environmental friendly nature. The present work demonstrates the bioreductive green synthesis of nanosized zinc oxide (ZnO using peel extracts of pomegranate. Highly crystalline ZnO nanoparticles (ZnO NPs which are 5 nm in particle size were characterised by HRTEM and XRD. FT-IR spectra confirmed the presence of the biomolecules and formation of plant protein-coated ZnO NPs and also the pure ZnO NPs. Electrochemical investigation revealed the redox properties and the conductivity of the as-prepared ZnO nanoparticles. The optical band gap of ZnO NPs was calculated to be 3.48 eV which indicates that ZnO NPs can be used in metal oxide semiconductor-based devices. Further, the nanomaterials were also found to be good inhibitors of bacterial strains at both low and high concentrations of 5–10 mg mL−1.

Hybrid bulk heterojunction solar cells based on poly(3-hexylthiophene) and ZnO nanoparticles modified by side-chain functional polythiophenes

International Nuclear Information System (INIS)

Li, Fan; Du, Yanhui; Chen, Yiwang

2012-01-01

We report the investigation of the hybrid bulk heterojunction solar cells based on the blend of poly(3-hexylthiophene) (P3HT) and ZnO nanoparticles modified by side-chain thiol functional poly(3-thiophenehexanethiol) (P3HT-SH). Grafting of P3HT-SH onto ZnO nanoparticles can promote the dispersion of ZnO nanoparticles within P3HT matrix and facilitate electron injection process into ZnO nanoparticles, resulting in a more efficient photoinduced charge transfer than that in simple physical mixture of P3HT and non-modified ZnO nanoparticles (P3HT/ZnO). Furthermore, the performance of hybrid photovoltaic device based on P3HT/P3HT-SH-modified ZnO blend exhibits an improved device efficiency compared with P3HT/ZnO even before thermal treatment. After being annealed at 80 °C, the P3HT/P3HT-SH-modified ZnO device shows the power conversion efficiency as high as 0.68%, with the short-circuit current density of 1.89 mA/cm 2 , the open-circuit voltage of 0.599 V and a fill factor of 60.5% under AM 1.5 G illumination with 100 mW/cm 2 light intensity. - Highlights: ► Hybrid solar cells based on poly(3-hexylthiophene) and modified ZnO nanoparticles ► ZnO nanoparticles modified by side-chain functional polythiophenes ► Uniform dispersion and intimate contact between polymers and nanoparticles ► Efficient charge transfer leading to the improvement of device efficiency

Structural, magnetic and optical properties of ZnO nanostructures converted from ZnS nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Patel, Prayas Chandra; Ghosh, Surajit; Srivastava, P.C., E-mail: pcsrivastava50@gmail.com

2016-09-15

Graphical abstract: The phase conversion of ZnS to highly crystalline hexagonal ZnO was done by heat treatment. - Highlights: • Phase change of cubic ZnS to hexagonal ZnO via heat treatment. • Band gap was found to decrease with increasing calcinations temperature. • ZnO samples have higher magnetic moment than ZnS. • Blocking Temperature of the samples is well above room temperature. • Maximum negative%MR with saturation value ∼38% was found for sample calcined at 600° C. - Abstract: The present work concentrates on the synthesis of cubic ZnS and hexagonal ZnO semiconducting nanoparticle from same precursor via co-precipitation method. The phase conversion of ZnS to highly crystalline hexagonal ZnO was done by heat treatment. From the analysis of influence of calcination temperature on the structural, optical and vibrational properties of the samples, an optimum temperature was found for the total conversion of ZnS nanoparticles to ZnO. Role of quantum confinement due to finite size is evident from the blue shift of the fundamental absorption in UV–vis spectra only in the ZnS nanoparticles. The semiconducting nature of the prepared samples is confirmed from the UV–vis, PL study and transport study. From the magnetic and transport studies, pure ZnO phase was found to be more prone to magnetic field.

Self-aligned nanocrystalline ZnO hexagons by facile solid-state and co-precipitation route

International Nuclear Information System (INIS)

Thorat, J. H.; Kanade, K. G.; Nikam, L. K.; Chaudhari, P. D.; Panmand, R. P.; Kale, B. B.

2012-01-01

In this study, we report the synthesis of well-aligned nanocrystalline hexagonal zinc oxide (ZnO) nanoparticles by facile solid-state and co-precipitation method. The co-precipitation reactions were performed using aqueous and ethylene glycol (EG) medium using zinc acetate and adipic acid to obtain zinc adipate and further decomposition at 450 °C to confer nanocrystalline ZnO hexagons. XRD shows the hexagonal wurtzite structure of the ZnO. Thermal study reveals complete formation of ZnO at 430 °C in case of solid-state method, whereas in case of co-precipitation method complete formation was observed at 400 °C. Field emission scanning electron microscope shows spherical morphology for ZnO synthesized by solid-state method. The aqueous-mediated ZnO by co-precipitation method shows rod-like morphology. These rods are formed via self assembling of spherical nanoparticles, however, uniformly dispersed spherical crystallites were seen in EG-mediated ZnO. Transmission electron microscope (TEM) investigations clearly show well aligned and highly crystalline transparent and thin hexagonal ZnO. The particle size was measured using TEM and was observed to be 50–60 nm in case of solid-state method and aqueous-mediated co-precipitation method, while 25–50 nm in case of EG-mediated co-precipitation method. UV absorption spectra showed sharp absorption peaks with a blue shift for EG-mediated ZnO, which demonstrate the mono-dispersed lower particle size. The band gap of the ZnO was observed to be 3.4 eV which is higher than the bulk, implies nanocrystalline nature of the ZnO. The photoluminescence studies clearly indicate the strong violet and weak blue emission in ZnO nanoparticles which is quite unique. The process investigated may be useful to synthesize other oxide semiconductors and transition metal oxides.

Self-aligned nanocrystalline ZnO hexagons by facile solid-state and co-precipitation route

Energy Technology Data Exchange (ETDEWEB)

Thorat, J. H. [Mahatma Phule College, Department of Chemistry (India); Kanade, K. G. [Annasaheb Awate College (India); Nikam, L. K. [B.G. College (India); Chaudhari, P. D.; Panmand, R. P.; Kale, B. B., E-mail: kbbb1@yahoo.com [Center for Materials for Electronics Technology (C-MET) (India)

2012-02-15

In this study, we report the synthesis of well-aligned nanocrystalline hexagonal zinc oxide (ZnO) nanoparticles by facile solid-state and co-precipitation method. The co-precipitation reactions were performed using aqueous and ethylene glycol (EG) medium using zinc acetate and adipic acid to obtain zinc adipate and further decomposition at 450 Degree-Sign C to confer nanocrystalline ZnO hexagons. XRD shows the hexagonal wurtzite structure of the ZnO. Thermal study reveals complete formation of ZnO at 430 Degree-Sign C in case of solid-state method, whereas in case of co-precipitation method complete formation was observed at 400 Degree-Sign C. Field emission scanning electron microscope shows spherical morphology for ZnO synthesized by solid-state method. The aqueous-mediated ZnO by co-precipitation method shows rod-like morphology. These rods are formed via self assembling of spherical nanoparticles, however, uniformly dispersed spherical crystallites were seen in EG-mediated ZnO. Transmission electron microscope (TEM) investigations clearly show well aligned and highly crystalline transparent and thin hexagonal ZnO. The particle size was measured using TEM and was observed to be 50-60 nm in case of solid-state method and aqueous-mediated co-precipitation method, while 25-50 nm in case of EG-mediated co-precipitation method. UV absorption spectra showed sharp absorption peaks with a blue shift for EG-mediated ZnO, which demonstrate the mono-dispersed lower particle size. The band gap of the ZnO was observed to be 3.4 eV which is higher than the bulk, implies nanocrystalline nature of the ZnO. The photoluminescence studies clearly indicate the strong violet and weak blue emission in ZnO nanoparticles which is quite unique. The process investigated may be useful to synthesize other oxide semiconductors and transition metal oxides.

Time dependent rise and decay of photocurrent in zinc oxide nanoparticles in ambient and vacuum medium

Science.gov (United States)

C, Rajkumar; Srivastava, Rajneesh K.

2018-05-01

Zinc oxide (ZnO) nanoparticle has been synthesized by cost effective Co-precipitation method and studied its photo-response activity. The synthesized ZnO nanomaterial was characterized by using various analytical techniques such as x-ray diffraction (XRD), UV–visible spectroscopy, FTIR spectroscopy, photoluminescence (PL) spectroscopy, and Scanning Electron Microscopy (SEM). From the XRD results, it is confirmed that synthesized ZnO nanomaterial possess hexagonal wurtzite phase structure with an average crystallite size of ∼16–17 nm. The UV-Visible absorption spectrum shows that it has blue shift compared to their bulk counterparts. Photoluminescence spectra of ZnO nanoparticles have a strong violet band at 423 nm and three weak bands at 485 nm (blue), 506 nm (green), and 529 nm (green). The presence of hydroxyl group was confirmed by FTIR. The photo-response analysis was studied by the time-dependent rise and decay photocurrent of ZnO nanoparticle was tested in the air as well as vacuum medium.

Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

International Nuclear Information System (INIS)

Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu

2014-01-01

The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H 2 in Ar ambient at 700 °C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between “on” and “off” states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (V Zn  + OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, V Zn  + OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57 μ B . The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism

Anchoring ZnO Nanoparticles in Nitrogen-Doped Graphene Sheets as a High-Performance Anode Material for Lithium-Ion Batteries

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Guanghui Yuan

2018-01-01

Full Text Available A novel binary nanocomposite, ZnO/nitrogen-doped graphene (ZnO/NG, is synthesized via a facile solution method. In this prepared ZnO/NG composite, highly-crystalline ZnO nanoparticles with a size of about 10 nm are anchored uniformly on the N-doped graphene nanosheets. Electrochemical properties of the ZnO/NG composite as anode materials are systematically investigated in lithium-ion batteries. Specifically, the ZnO/NG composite can maintain the reversible specific discharge capacity at 870 mAh g−1 after 200 cycles at 100 mA g−1. Besides the enhanced electronic conductivity provided by interlaced N-doped graphene nanosheets, the excellent lithium storage properties of the ZnO/NG composite can be due to nanosized structure of ZnO particles, shortening the Li+ diffusion distance, increasing reaction sites, and buffering the ZnO volume change during the charge/discharge process.

Kinetics activity of Yersinia Intermedia Against ZnO Nanoparticles Either Synergism Antibiotics by Double-Disc Synergy Test Method.

Science.gov (United States)

Fathi Azar Khavarani, Motahareh; Najafi, Mahla; Shakibapour, Zahra; Zaeifi, Davood

2016-03-01

Bacterial resistance to the commonly used antibacterial agents is an increasing challenge in the medicine, and a major problem for the health care systems; the control of their spread is a constant challenge for the hospitals. In this study, we have investigated the antimicrobial activity of the Zinc Oxide nanoparticles against clinical sample; Yersinia intermedia bacteria. Nanoparticle susceptibility constants and death kinetic were used to evaluate the antimicrobial characteristics of the Zinc Oxide (ZnO) against the bacteria. Antimicrobial tests were performed with 10 8 cfu.mL -1 at baseline. At first, Minimum Inhibitory Concentration (MIC) of ZnO was determined and then nanoparticle suspension at one and two times of the MIC was used for death kinetic and susceptibility constant assay at 0 to 360 min treatment time. ZnO nanoparticles with size ranging from 10 to 30 nm showed the highest susceptibility reaction against Y. intermedia (Z=39.06 mL.μg -1 ). The process of Y. intermedia death in ZnO suspension was assumed to follow the first-order kinetics and the survival ratio of bacteria decreased with the increasing treatment time. An increased concentration of the nanoparticle was seen to enhance the bactericidal action of the nanoparticle. Then we performed the best ratio of the nanoparticles on semi-sensitive and resistance antibiotic for the bacteria. However, based on experimental results, synergy of ZnO nanoparticles and Oxacilin was determined and Y. intermedia showed a higher sensitivity compared to the ZnO nanoparticles alone. The results of the present study illustrates that ZnO has a strong antimicrobial effect and could potentially be employed to aid the bacterial control. It could also improve- antibacterial effects in combination with the antibiotics.

Effects of subtoxic concentrations of TiO2 and ZnO nanoparticles on human lymphocytes, dendritic cells and exosome production.

Science.gov (United States)

Andersson-Willman, Britta; Gehrmann, Ulf; Cansu, Zekiye; Buerki-Thurnherr, Tina; Krug, Harald F; Gabrielsson, Susanne; Scheynius, Annika

2012-10-01

Metal oxide nanoparticles are widely used in the paint and coating industry as well as in cosmetics, but the knowledge of their possible interactions with the immune system is very limited. Our aims were to investigate if commercially available TiO(2) and ZnO nanoparticles may affect different human immune cells and their production of exosomes, nano-sized vesicles that have a role in cell to cell communication. We found that the TiO(2) or ZnO nanoparticles at concentrations from 1 to 100μg/mL did not affect the viability of primary human peripheral blood mononuclear cells (PBMC). In contrast, monocyte-derived dendritic cells (MDDC) reacted with a dose dependent increase in cell death and caspase activity to ZnO but not to TiO(2) nanoparticles. Non-toxic exposure, 10μg/mL, to TiO(2) and ZnO nanoparticles did not significantly alter the phenotype of MDDC. Interestingly, ZnO but not TiO(2) nanoparticles induced a down regulation of FcγRIII (CD16) expression on NK-cells in the PBMC population, suggesting that subtoxic concentrations of ZnO nanoparticles might have an effect on FcγR-mediated immune responses. The phenotype and size of exosomes produced by PBMC or MDDC exposed to the nanoparticles were similar to that of exosomes harvested from control cultures. TiO(2) or ZnO nanoparticles could not be detected within or associated to exosomes as analyzed with TEM. We conclude that TiO(2) and ZnO nanoparticles differently affect immune cells and that evaluations of nanoparticles should be performed even at subtoxic concentrations on different primary human immune cells when investigating potential effects on immune functions. Copyright © 2012 Elsevier Inc. All rights reserved.

Development of zinc oxide nanoparticle by sonochemical method and study of their physical and optical properties

International Nuclear Information System (INIS)

Khan, Samreen Heena; Suriyaprabha, R.; Pathak, Bhawana; Fulekar, M. H.

2016-01-01

With the miniaturization of crystal size, the fraction of under-coordinated surface atoms becomes dominant, and hence, materials in the nano-regime behave very differently from the similar material in a bulk. Zinc oxide (ZnO), particularly, exhibits extraordinary properties such as a wide direct band gap (3.37 eV), large excitation binding energy (60 meV), low refractive index (1.9), stability to intense ultraviolet (UV) illumination, resistance to high-energy irradiation, and lower toxicity as compared to other semiconductors. This very property makes Zinc Oxide a potential candidate in many application fields, particularly as a prominent semiconductor. Zinc Oxide plays a significant role in many technological advances with its application in semiconductor mediated photocatalytic processes and sensor, solar cells and others. In present study, Zinc Oxide (ZnO) has been synthesized using three different precursors by sonochemical method. Zinc Acetate Dihydrate, Zinc Nitrate Hexahydrate and Zinc Sulphate Heptahydrate used as a precursor for the synthesis process. The synthesized ZnO nanoparticle has been found under the range of ∼50 nm. Zinc oxide nanoparticles were characterized using different characterizing tools. The as-synthesized ZnO was characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) for the determination of functional group; Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS) for Morphology and elemental detection respectively, Transmission Electron Microscopy for Particle size distribution and morphology and X-Ray Diffraction (XRD) for the confirmation of crystal structure of the nanomaterial. The optical properties of the ZnO were examined by UV-VIS spectroscopy equipped with Diffuse Reflectance spectroscopy (DRS) confirmed the optical band gap of ZnO-3 around 3.23 eV resembles with the band gap of bulk ZnO (3.37eV). The TEM micrograph of the as-synthesized material showed perfectly spherical shaped

Development of zinc oxide nanoparticle by sonochemical method and study of their physical and optical properties

Energy Technology Data Exchange (ETDEWEB)

Khan, Samreen Heena, E-mail: samreen.heena.khan@gmail.com; Suriyaprabha, R. [Centre for Nanosciences, Central University of Gujarat, Gandhinagar, India- 382030 (India); Pathak, Bhawana, E-mail: bhawana.pathak@cug.ac.in; Fulekar, M. H., E-mail: mhfulekar@yahoo.com [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar, India- 382030 (India)

2016-04-13

With the miniaturization of crystal size, the fraction of under-coordinated surface atoms becomes dominant, and hence, materials in the nano-regime behave very differently from the similar material in a bulk. Zinc oxide (ZnO), particularly, exhibits extraordinary properties such as a wide direct band gap (3.37 eV), large excitation binding energy (60 meV), low refractive index (1.9), stability to intense ultraviolet (UV) illumination, resistance to high-energy irradiation, and lower toxicity as compared to other semiconductors. This very property makes Zinc Oxide a potential candidate in many application fields, particularly as a prominent semiconductor. Zinc Oxide plays a significant role in many technological advances with its application in semiconductor mediated photocatalytic processes and sensor, solar cells and others. In present study, Zinc Oxide (ZnO) has been synthesized using three different precursors by sonochemical method. Zinc Acetate Dihydrate, Zinc Nitrate Hexahydrate and Zinc Sulphate Heptahydrate used as a precursor for the synthesis process. The synthesized ZnO nanoparticle has been found under the range of ∼50 nm. Zinc oxide nanoparticles were characterized using different characterizing tools. The as-synthesized ZnO was characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) for the determination of functional group; Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS) for Morphology and elemental detection respectively, Transmission Electron Microscopy for Particle size distribution and morphology and X-Ray Diffraction (XRD) for the confirmation of crystal structure of the nanomaterial. The optical properties of the ZnO were examined by UV-VIS spectroscopy equipped with Diffuse Reflectance spectroscopy (DRS) confirmed the optical band gap of ZnO-3 around 3.23 eV resembles with the band gap of bulk ZnO (3.37eV). The TEM micrograph of the as-synthesized material showed perfectly spherical shaped

Microstructure, electronic structure and optical properties of combustion synthesized Co doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Srinatha, N. [Department of Physics, JB Campus, Bangalore University, Bangalore 560056 (India); Nair, K.G.M. [UGC-DAE-CSR, Kalpakkam Node, Kalpakkam, Kokilamedu 603102 (India); Angadi, Basavaraj, E-mail: brangadi@gmail.com [Department of Physics, JB Campus, Bangalore University, Bangalore 560056 (India)

2015-10-01

We report on the microstructure, electronic structure and optical properties of nanocrystalline Zn{sub 1−x}Co{sub x}O (x=0, 0.01, 0.03, 0.05 and 0.07) particles prepared by solution combustion technique using L-Valine as fuel. The detailed structural and micro-structural studies were carried out by XRD, HRTEM and TEM-SAED respectively, which confirms the formation of single phased, nano-sized particles. The electronic structure was determined through NEXAFS and atomic multiplet calculations/simulations performed for various symmetries and valence states of ‘Co’ to determine the valance state, symmetry and crystal field splitting. The correlations between the experimental NEXAFS spectra and atomic multiplet simulations, confirms that, ‘Co’ present is in the 2+ valence state and substituted at the ‘Zn’ site in tetrahedral symmetry with crystal field splitting, 10Dq =−0.6 eV. The optical properties and ‘Co’ induced defect formation of as-synthesized materials were examined by using diffuse reflectance and Photoluminescence spectroscopy, respectively. Red-shift of band gap energy (E{sub g}) was observed in Zn{sub 1−x}Co{sub x}O samples due to Co (0.58 Å) substitution at Zn (0.60 Å) site of the host ZnO. Also, in PL spectra, a prominent pre-edge peak corresponds to ultraviolet (UV) emission around 360–370 nm was observed with Co concentration along with near band edge emission (NBE) of the wide band gap ZnO and all samples show emission in the blue region.

UV-cured polymeric films containing ZnO and silver nanoparticles with UV–vis light-assisted photocatalytic activity

International Nuclear Information System (INIS)

Podasca, Viorica E.; Buruiana, Tinca; Buruiana, Emil C.

2016-01-01

Highlights: • Synthesis of photopolymerized films containing ZnO and/or Ag NPs is reported. • Photopolymerization of the acrylic monomers occurred with conversions of 57–90%. • XRD, EDX, and TEM analyses proved the uniform distribution of NPs in the matrix. • MB was photodegradated using the hybrid films under UV–vis irradiation. - Abstract: Hybrid polymer composites incorporating preformed ZnO alone or its mixture with Ag nanoparticles created during UV irradiation of some urethane acrylic monomers including trietoxysilylpropyl carbamoyloxyethyl methacrylate were synthesized and characterized by spectroscopic ("1H ("1"3C) NMR, FTIR, UV–vis, fluorescence, X-ray diffraction) and microscopic (AFM, ESEM/EDX, TEM) techniques. The results confirmed that the double bond conversion measured through FTIR spectroscopy varied in the range of 57–90% (after 60 s of irradiation), exhibiting formulation composition dependence. In the crosslinked polymer networks the existence of individual nanoparticles with primarily spherical shape and sizes between 5 and 15 nm for ZnO, and around 3 nm for in situ photogenerated silver nanoparticles was evidenced. Additionally, the photocatalytic effect of the photopolymerized hybrid films was investigated by determining the decomposition rate of the methylene blue (MB) in ethanol (over 90%) under UV (2.7 × 10"−"2 s"−"1) and visible irradiation (2.9 × 10"−"2 min"−"1). It was found that the composite films containing a higher amount of ZnO-Ag nanoparticles placed in water induced the photodecomposition of MB (∼87% after 100 min of visible irradiation; k = 2.1 × 10"−"2 min"−"1). The good efficiency of the NPs from these polymer films make them attractive for applications in photocatalysis of organic dye molecules.

UV-cured polymeric films containing ZnO and silver nanoparticles with UV–vis light-assisted photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Podasca, Viorica E.; Buruiana, Tinca; Buruiana, Emil C., E-mail: emilbur@icmpp.ro

2016-07-30

Highlights: • Synthesis of photopolymerized films containing ZnO and/or Ag NPs is reported. • Photopolymerization of the acrylic monomers occurred with conversions of 57–90%. • XRD, EDX, and TEM analyses proved the uniform distribution of NPs in the matrix. • MB was photodegradated using the hybrid films under UV–vis irradiation. - Abstract: Hybrid polymer composites incorporating preformed ZnO alone or its mixture with Ag nanoparticles created during UV irradiation of some urethane acrylic monomers including trietoxysilylpropyl carbamoyloxyethyl methacrylate were synthesized and characterized by spectroscopic ({sup 1}H ({sup 13}C) NMR, FTIR, UV–vis, fluorescence, X-ray diffraction) and microscopic (AFM, ESEM/EDX, TEM) techniques. The results confirmed that the double bond conversion measured through FTIR spectroscopy varied in the range of 57–90% (after 60 s of irradiation), exhibiting formulation composition dependence. In the crosslinked polymer networks the existence of individual nanoparticles with primarily spherical shape and sizes between 5 and 15 nm for ZnO, and around 3 nm for in situ photogenerated silver nanoparticles was evidenced. Additionally, the photocatalytic effect of the photopolymerized hybrid films was investigated by determining the decomposition rate of the methylene blue (MB) in ethanol (over 90%) under UV (2.7 × 10{sup −2} s{sup −1}) and visible irradiation (2.9 × 10{sup −2} min{sup −1}). It was found that the composite films containing a higher amount of ZnO-Ag nanoparticles placed in water induced the photodecomposition of MB (∼87% after 100 min of visible irradiation; k = 2.1 × 10{sup −2} min{sup −1}). The good efficiency of the NPs from these polymer films make them attractive for applications in photocatalysis of organic dye molecules.

Modulation of defect-mediated energy transfer from ZnO nanoparticles for the photocatalytic degradation of bilirubin

Directory of Open Access Journals (Sweden)

Tanujjal Bora

2013-11-01

Full Text Available In recent years, nanotechnology has gained significant interest for applications in the medical field. In this regard, a utilization of the ZnO nanoparticles for the efficient degradation of bilirubin (BR through photocatalysis was explored. BR is a water insoluble byproduct of the heme catabolism that can cause jaundice when its excretion is impaired. The photocatalytic degradation of BR activated by ZnO nanoparticles through a non-radiative energy transfer pathway can be influenced by the surface defect-states (mainly the oxygen vacancies of the catalyst nanoparticles. These were modulated by applying a simple annealing in an oxygen-rich atmosphere. The mechanism of the energy transfer process between the ZnO nanoparticles and the BR molecules adsorbed at the surface was studied by using steady-state and picosecond-resolved fluorescence spectroscopy. A correlation of photocatalytic degradation and time-correlated single photon counting studies revealed that the defect-engineered ZnO nanoparticles that were obtained through post-annealing treatments led to an efficient decomposition of BR molecules that was enabled by Förster resonance energy transfer.

Photocatalytic removal of doxycycline from aqueous solution using ZnO nano-particles: a comparison between UV-C and visible light.

Science.gov (United States)

Pourmoslemi, Shabnam; Mohammadi, Ali; Kobarfard, Farzad; Amini, Mohsen

2016-10-01

Zinc oxide nano-particles were synthesized, characterized and used for photocatalytic degradation of doxycycline using UV-C and visible light. Effects of several operational factors including initial pH of antibiotic solution, initial antibiotic concentration and ZnO nano-particles loading amount were investigated. Comparing photocatalytic degradation and mineralization of doxycycline under UV-C and visible light showed successful application of the method under both light sources. However, reaction rate was higher under UV-C irradiation, which degraded doxycycline almost completely in 5 hours, and 68% mineralization was achieved. Synthesized ZnO nano-particles were successfully applied for photocatalytic degradation of doxycycline in a pharmaceutical wastewater sample. The process was fitted to the pseudo first order kinetic model with rate constants in the range of 6-22(×10 -3 ) mg L -1 min -1 with respect to initial concentration of doxycycline under UV-C irradiation. The Langmuir-Hinshelwood model was also employed for describing the photocatalytic reaction with surface reaction kinetic constant k c and equilibrium adsorption constant K LH values calculated as 0.12 mg L -1 min -1 and 2.2 L mg -1 , respectively. Degradation of doxycycline was followed by UV-visible spectroscopy and a validated stability indicating high-performance liquid chromatography method that was developed using stressed samples of doxycycline and could selectively determine doxycycline in the presence of its degradation products. Mass spectrometry was used for determining final degradation products.

Effect of nanocomposite packaging containing ZnO on growth of Bacillus subtilis and Enterobacter aerogenes

Energy Technology Data Exchange (ETDEWEB)

Esmailzadeh, Hakimeh [National Nutrition and Food Technology Research Institute, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sangpour, Parvaneh, E-mail: Sangpour@merc.ac.ir [Nanotechnology and Advanced Materials Department, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of); Shahraz, Farzaneh [National Nutrition and Food Technology Research Institute, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hejazi, Jalal [Department of Biochemistry and Nutrition, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan (Iran, Islamic Republic of); Khaksar, Ramin [National Nutrition and Food Technology Research Institute, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2016-01-01

Recent advances in nanotechnology have opened new windows in active food packaging. Nano-sized ZnO is an inexpensive material with potential antimicrobial properties. The aim of the present study is to evaluate the antibacterial effect of low density Polyethylene (LDPE) containing ZnO nanoparticles on Bacillus subtilis and Enterobacter aerogenes. ZnO nanoparticles have been synthesized by facil molten salt method and have been characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). Nanocomposite films containing 2 and 4 wt.% ZnO nanoparticles were prepared by melt mixing in a twin-screw extruder. The growth of both microorganisms has decreased in the presence of ZnO containing nanocomposites compared with controls. Nanocomposites with 4 wt.% ZnO nanoparticles had stronger antibacterial effect against both bacteria in comparison with the 2 wt.% ZnO containing nanocomposites. B. subtilis as Gram-positive bacteria were more sensitive to ZnO containing nanocomposite films compared with E. aerogenes as Gram-negative bacteria. There were no significant differences between the migration of Zn ions from 2 and 4 wt.% ZnO containing nanocomposites and the released Zn ions were not significantly increased in both groups after 14 days compared with the first. Regarding the considerable antibacterial effects of ZnO nanoparticles, their application in active food packaging can be a suitable solution for extending the shelf life of food. - Highlights: • ZnO containing nanocomposites decreased growth of both B. subtilis and E. aerogenes. • B. subtilis was more sensitive to ZnO containing nanocomposites. • The migration of Zn ions from nanocomposites was negligible.

Characterization and photocatalytic properties of cotton fibers modified with ZnO nanoparticles using sol–gel spin coating technique

Directory of Open Access Journals (Sweden)

Mohamed Shaban

2016-09-01

Full Text Available Zinc oxide nanoparticles (ZnO NPs were prepared using the sol–gel method. Cotton fibers were loaded with ZnO nanoparticles using sol–gel spin coating technique. The prepared ZnO NPs and ZnO-coated cotton were characterized by scanning electron microscope (SEM and energy dispersive X-ray spectroscopy (EDX. The self-cleaning property of ZnO-coated cotton and the photocatalytic removal of methyl orange dye from the contaminated water and cotton fibers were studied by measuring the optical absorbance after exposure to sunlight and Philips 200W lamp illumination. The results showed that the cotton loaded with ZnO nanoparticles could efficiently decompose 73% of methyl orange dye in the sunlight and 30.7% in the lamp illumination after 12 hours. ZnO nanoparticles decomposed methyl orange dye by 92.7% in the sunlight and 26.4% in the lamp illumination after 7 hours.

Synthesis of Mn doped ZnO nanoparticles with biocompatible capping

International Nuclear Information System (INIS)

Sharda; Jayanthi, K.; Chawla, Santa

2010-01-01

Free standing nanoparticles of ZnO doped with transition metal ion Mn have been prepared by solid state reaction method at 500 deg. C. X-ray diffraction (XRD) analysis confirmed high quality monophasic wurtzite hexagonal structure with particle size of 50 nm and no signature of dopant as separate phase. Incorporation of Mn has been confirmed with EDS. Bio-inorganic interface was created by capping the nanoparticles with heteromultifunctional organic stabilizer mercaptosuccinic acid (MSA). The surface morphological studies by scanning electron microscopy (SEM) showed formation of spherical particles and the nanoballs grow in size uniformly with MSA capping. MSA capping has been confirmed with thermo gravimetric analysis (TGA) and FTIR. Photoluminescence (PL) studies show that the ZnO:Mn 2+ particles are excitable by blue light and emits in orange and red. Occurrence of room temperature ferromagnetism in Mn doped ZnO makes such biocompatible luminescent magnetic nanoparticles very promising material.

Antimicrobial effects of zinc oxide nanoparticles modified with silver

International Nuclear Information System (INIS)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes

2016-01-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Antimicrobial effects of zinc oxide nanoparticles modified with silver

Energy Technology Data Exchange (ETDEWEB)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes, E-mail: rayssasouza.net@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil)

2016-07-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Initial transport and retention behaviors of ZnO nanoparticles in quartz sand porous media coated with Escherichia coli biofilm

International Nuclear Information System (INIS)

Jiang, Xujia; Wang, Xueting; Tong, Meiping; Kim, Hyunjung

2013-01-01

The significance of biofilm on the transport and deposition behaviors of ZnO nanoparticles were examined under a series of environmentally relevant ionic strength at two fluid velocities of 4 m-d −1 and 8 m-d −1 . Biofilm enhanced nanoparticles retention in porous media under all examined conditions. The greater deposition was also observed in extracellular polymeric substances (EPS) coated surfaces by employment of quartz microbalance with dissipation (QCM-D) system. Derjaguin–Landau–Verwey–Overbeek (DLVO) failed to interpret more ZnO nanoparticles deposition on biofilm (EPS) coated silica surfaces. Chemical interaction and physical morphology of biofilm contributed to this greater deposition (retention). Biofilm affected the spacial distribution of retained ZnO nanoparticles as well. Relatively steeper slope of retained profiles were observed in the presence of biofilm, corresponding to the greater deviation from colloid filtration theory (CFT). Pore space constriction via biofilm induced more nanoparticle trapped in the column inlet, leading to greater deviations (σln k f ) from the CFT. Highlights: ► Biofilm reduced the mobility of ZnO nanoparticles in column. ► DLVO and non-DLVO interactions contributed the more nanoparticles deposition. ► Biofilm also affected the spacial distribution of ZnO nanoparticles in column. ► Greater deviation from classic filtration theory was observed with biofilm. ► Physical structure of biofilm induced greater deviation from log-linear prediction. -- Biofilm enhanced ZnO nanoparticle deposition and altered spacial distribution in porous media

Spectroscopic characterization and docking studies of ZnO nanoparticle modified with BSA

Science.gov (United States)

Ledesma, Ana E.; Chemes, Doly María; Frías, María de los Angeles; Guauque Torres, Maria del Pilar

2017-08-01

Nanoparticles (NP) into a biological environment are an interesting topic for diagnosis and therapy in applications for medicine or environment and the knowledge about this interaction is important from the perspective of safe use of nanomaterials. In the current study, we characterized the type of interaction and the orientation of bovine serum albumin (BSA) adsorbed on ZnO nanoparticle surfaces as a function of size, using molecular docking. To probe experimentally different theoretical hypothesis about the interaction, ZnO-NPs were prepared in aqueous solution, and then were bioconjugated with BSA. Transmission electron microscopy (TEM) and Raman spectroscopy confirm the spherical shape of NP and the irreversible adsorption of BSA on NP surface. Raman and Infrared spectroscopy (FTIR) reveal that BSA interaction with ZnO nanoparticle produced a conformational rearrangement into protein, observing changes in Tyr and Trp environment, a minor percentage of α-helix structure and a more extended chain. The fluorescence analysis demonstrated that when BSA concentration higher than 30 μM is used the signal due to the self-oligomerization of protein overlaps with the ZnO nanoparticle emission. The results predicted that the most probable interaction site is near to domain IB and IIA and ionic interactions are the major responsible for the binding. Thermal stability studies reveals that the denaturalization temperature of BSA increase from 57 °C to 65 °C in presence of ZnO NP and their esterase-like activity was improved.

Sparking deposited ZnO nanoparticles as double-layered photoelectrode in ZnO dye-sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Hongsith, Kritsada [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP center), CHE, Bangkok 10400 (Thailand); Hongsith, Niyom [Thailand Center of Excellence in Physics (ThEP center), CHE, Bangkok 10400 (Thailand); School of Science, University of Phayao, Phayao 56000 (Thailand); Wongratanaphisan, Duangmanee; Gardchareon, Atcharawon; Phadungdhitidhada, Surachet [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP center), CHE, Bangkok 10400 (Thailand); Singjai, Pisith [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Choopun, Supab, E-mail: supab99@gmail.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP center), CHE, Bangkok 10400 (Thailand)

2013-07-31

The semiconducting layers of ZnO nanoparticles (ZN), ZnO powder (ZP) and ZnO nanopowder (ZNP) were designed and fabricated for double-layered semiconducting photoelectrode in dye-sensitized solar cells (DSSCs). The under-layer was ZN, which was prepared by simple and cost-effective sparking technique onto F-doped tin oxide (FTO) glass substrate and its thickness was controlled by number of sparking cycles for 0, 10, 25, 50 and 100 rounds under atmospheric pressure. Then, ZP or ZNP was screened on to ZN to form double-layered photoelectrode. Here, the DSSC structures were FTO/double-layered ZnO/Eosin Y/electrolyte/Pt counterelectrode. The best results of DSSCs were observed with J{sub sc} of 4.71 mA/cm{sup 2} and 5.56 mA/cm{sup 2} and photoconversion efficiency of 1.11% and 1.14% at 50 sparking cycles for ZP and ZNP over-layers, respectively. The efficiency enhancement can be explained by combination effects of electron and light scattering. Moreover, the modified equation of short circuit current density was developed and effectively used to explain the efficiency enhancement. - Highlights: • Effect of under-layer thickness is investigated. • Simple and cost-effective sparking technique is used for ZnO nanoparticles. • Efficiency enhancement can be explained by both electron and light scattering. • Modified equation of short circuit current density was developed for enhancement.

Sparking deposited ZnO nanoparticles as double-layered photoelectrode in ZnO dye-sensitized solar cell

International Nuclear Information System (INIS)

Hongsith, Kritsada; Hongsith, Niyom; Wongratanaphisan, Duangmanee; Gardchareon, Atcharawon; Phadungdhitidhada, Surachet; Singjai, Pisith; Choopun, Supab

2013-01-01

The semiconducting layers of ZnO nanoparticles (ZN), ZnO powder (ZP) and ZnO nanopowder (ZNP) were designed and fabricated for double-layered semiconducting photoelectrode in dye-sensitized solar cells (DSSCs). The under-layer was ZN, which was prepared by simple and cost-effective sparking technique onto F-doped tin oxide (FTO) glass substrate and its thickness was controlled by number of sparking cycles for 0, 10, 25, 50 and 100 rounds under atmospheric pressure. Then, ZP or ZNP was screened on to ZN to form double-layered photoelectrode. Here, the DSSC structures were FTO/double-layered ZnO/Eosin Y/electrolyte/Pt counterelectrode. The best results of DSSCs were observed with J sc of 4.71 mA/cm 2 and 5.56 mA/cm 2 and photoconversion efficiency of 1.11% and 1.14% at 50 sparking cycles for ZP and ZNP over-layers, respectively. The efficiency enhancement can be explained by combination effects of electron and light scattering. Moreover, the modified equation of short circuit current density was developed and effectively used to explain the efficiency enhancement. - Highlights: • Effect of under-layer thickness is investigated. • Simple and cost-effective sparking technique is used for ZnO nanoparticles. • Efficiency enhancement can be explained by both electron and light scattering. • Modified equation of short circuit current density was developed for enhancement

Surface strain engineering through Tb doping to study the pressure dependence of exciton-phonon coupling in ZnO nanoparticles

International Nuclear Information System (INIS)

Sharma, A.; Dhar, S.; Singh, B. P.; Nayak, C.; Bhattacharyya, D.; Jha, S. N.

2013-01-01

A compressive hydrostatic strain has been found to develop in the ZnO lattice as a result of accumulation of Tb ions on the surface of the nanoparticles for Tb mole-fraction less than 0.04. This hydrostatic strain can be controlled up to ≈14 GPa by varying the Tb mole-fraction. Here, we have utilized this novel technique of surface strain engineering through Tb doping for introducing hydrostatic compressive strain in the lattice to study the pressure dependent electronic and vibrational properties of ZnO nanoparticles. Our study reveals that when subjected to pressure, nanoparticles of ZnO behave quite differently than bulk in many aspects. Unlike bulk ZnO, which is reported to go through a wurtzite to rock-salt structural phase transition at ≈8 GPa, ZnO nanoparticles do not show such transition and remain in wurtzite phase even at 14 GPa of pressure. Furthermore, the Grüneisen parameters for the optical phonon modes are found to be order of magnitude smaller in ZnO nanoparticles as compared to bulk. Our study also suggests an increase of the dielectric constant with pressure, which is opposite to what has been reported for bulk ZnO. Interestingly, it has also been found that the exciton-phonon interaction depends strongly upon pressure in this system. The exciton-phonon coupling has been found to decrease as pressure increases. A variational technique has been adopted to theoretically calculate the exciton-LO phonon coupling coefficient in ZnO nanoparticles as a function of pressure, which shows a good agreement with the experimental results. These findings imply that surface engineering of ZnO nanoparticles with Tb could indeed be an efficient tool to enhance and control the optical performance of this material

Surface strain engineering through Tb doping to study the pressure dependence of exciton-phonon coupling in ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sharma, A.; Dhar, S., E-mail: dhar@phy.iitb.ac.in; Singh, B. P. [Physics Department, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Nayak, C.; Bhattacharyya, D. [Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Jha, S. N. [Raja Ramanna Centre for Advanced Technology (RRCAT), Indore (India)

2013-12-07

A compressive hydrostatic strain has been found to develop in the ZnO lattice as a result of accumulation of Tb ions on the surface of the nanoparticles for Tb mole-fraction less than 0.04. This hydrostatic strain can be controlled up to ≈14 GPa by varying the Tb mole-fraction. Here, we have utilized this novel technique of surface strain engineering through Tb doping for introducing hydrostatic compressive strain in the lattice to study the pressure dependent electronic and vibrational properties of ZnO nanoparticles. Our study reveals that when subjected to pressure, nanoparticles of ZnO behave quite differently than bulk in many aspects. Unlike bulk ZnO, which is reported to go through a wurtzite to rock-salt structural phase transition at ≈8 GPa, ZnO nanoparticles do not show such transition and remain in wurtzite phase even at 14 GPa of pressure. Furthermore, the Grüneisen parameters for the optical phonon modes are found to be order of magnitude smaller in ZnO nanoparticles as compared to bulk. Our study also suggests an increase of the dielectric constant with pressure, which is opposite to what has been reported for bulk ZnO. Interestingly, it has also been found that the exciton-phonon interaction depends strongly upon pressure in this system. The exciton-phonon coupling has been found to decrease as pressure increases. A variational technique has been adopted to theoretically calculate the exciton-LO phonon coupling coefficient in ZnO nanoparticles as a function of pressure, which shows a good agreement with the experimental results. These findings imply that surface engineering of ZnO nanoparticles with Tb could indeed be an efficient tool to enhance and control the optical performance of this material.

Optical and Magnetic Properties of Fe Doped ZnO Nanoparticles Obtained by Hydrothermal Synthesis

Directory of Open Access Journals (Sweden)

Xiaojuan Wu

2014-01-01

Full Text Available Diluted magnetic semiconductors Zn1-xFexO nanoparticles with different doping concentration (x=0, 0.01, 0.05, 0.10, and 0.20 were successfully synthesized by hydrothermal method. The crystal structure, morphology, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD, energy dispersive spectrometer (EDS, high-resolution transmission electron microscopy (HRTEM, Raman scattering spectra (Raman, photoluminescence spectra (PL, and the vibrating sample magnetometer (VSM. The experiment results show that all samples synthesized by this method possess hexagonal wurtzite crystal structure with good crystallization, no other impurity phases are observed, and the morphology of the sample shows the presence of ellipsoidal nanoparticles. All the Fe3+ successfully substituted for the lattice site of Zn2+ and generates single-phase Zn1-xFexO. Raman spectra shows that the peak shifts to higher frequency. PL spectra exhibit a slight blue shift and the UV emission is annihilated with the increase of Fe3+ concentration. Magnetic measurements indicated that Fe-doped ZnO samples exhibit ferromagnetic behavior at room temperature and the saturation magnetization is enhanced with the increase of iron doping content.

Responses of human cells to ZnO nanoparticles: a gene transcription study†

Science.gov (United States)

Moos, Philip J.; Olszewski, Kyle; Honeggar, Matthew; Cassidy, Pamela; Leachman, Sancy; Woessner, David; Cutler, N. Shane; Veranth, John M.

2013-01-01

The gene transcript profile responses to metal oxide nanoparticles was studied using human cell lines derived from the colon and skin tumors. Much of the research on nanoparticle toxicology has focused on models of inhalation and intact skin exposure, and effects of ingestion exposure and application to diseased skin are relatively unknown. Powders of nominally nanosized SiO2, TiO2, ZnO and Fe2O3 were chosen because these substances are widely used in consumer products. The four oxides were evaluated using colon-derived cell lines, RKO and CaCo-2, and ZnO and TiO2 were evaluated further using skin-derived cell lines HaCaT and SK Mel-28. ZnO induced the most notable gene transcription changes, even though this material was applied at the lowest concentration. Nano-sized and conventional ZnO induced similar responses suggesting common mechanisms of action. The results showed neither a non-specific response pattern common to all substances nor synergy of the particles with TNF-α cotreatment. The response to ZnO was not consistent with a pronounced proinflammatory signature, but involved changes in metal metabolism, chaperonin proteins, and protein folding genes. This response was observed in all cell lines when ZnO was in contact with the human cells. When the cells were exposed to soluble Zn, the genes involved in metal metabolism were induced but the genes involved in protein refoldling were unaffected. This provides some of the first data on the effects of commercial metal oxide nanoparticles on human colon-derived and skin-derived cells. PMID:21769377

Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu, E-mail: ycwu@whu.edu.cn [School of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory, Wuhan University, Wuhan 430072 (China)

2014-01-21

The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H{sub 2} in Ar ambient at 700 °C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between “on” and “off” states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (V{sub Zn} + OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, V{sub Zn} + OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57 μ{sub B}. The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism.

Investigation on Fe-doped ZnO nanostructures prepared by a chemical route

International Nuclear Information System (INIS)

Mishra, A.K.; Das, D.

2010-01-01

Zn 1-x Fe x O (x = 0.03, 0.05 and 0.07) nanoparticles synthesized by a chemical route were characterized by different techniques. The structural characterization by XRD and TEM confirmed the phase purity of the samples and indicated a reduction in particle size with increase in the dopant (Fe) concentration in ZnO. The optical characterization of the nanoparticles by FTIR, PL and UV-visible spectroscopy confirmed the formation of wurtzite structure and incorporation of Fe in the ZnO lattice. Magnetization measurements by VSM and Faraday balance techniques indicate presence of room temperature ferromagnetism in the Fe-doped ZnO samples. Local environment around the Fe atoms has been probed by 57 Fe Moessbauer spectroscopy and the measured isomer shifts confirmed the charge state of iron as Fe 3+ . Positron annihilation lifetime spectroscopy (PALS) measurements confirm the presence of cation vacancies in the nanoparticles and indicate a reduction of overall defect concentration with incorporation of Fe atoms in the ZnO structure.

The structural properties of flower-like ZnO nanostructures on porous silicon

Science.gov (United States)

Eswar, Kevin Alvin; Suhaimi, Mohd Husairi Fadzillah; Guliling, Muliyadi; Mohamad, Maryam; Khusaimi, Zuraida; Rusop, M.; Abdullah, Saifollah

2018-05-01

The flower-like zinc oxide (ZnO) were successfully synthesized on porous silicon (PSi) via hydrothermal method. The characteristic of ZnO nanostructures was investigated using field emission scanning microscopy (FESEM) and X-ray diffraction (X-Ray). The FESEM images show the flower-like ZnO nanostructures composed ZnO nanoparticles. The X-ray diffraction shows that strong intensity of (100), (002) and (101) peaks. The structural analysis revealed that the peaks angles were shifted due to the stress or imperfection of the crystalline of ZnO nanostructures. The crystalline sizes in range of 42.60 to 54.09 nm were produced.

Experimental and theoretical investigations on magnetic behavior of (Al,Co) co-doped ZnO nanoparticles.

Science.gov (United States)

Jayakumar, O D; Achary, S N; Sudakar, C; Naik, R; Salunke, H G; Rao, Rekha; Peng, X; Ahuja, R; Tyagi, A K

2010-08-01

We present the structural and magnetic properties of Zn(0.95-x)Co(0.05)Al(x)O (x = 0.0 to 0.1) nanoparticles, synthesized by a novel sol-gel route followed by pyrolysis. Powder X-ray diffraction data confirms the formation of a single phase wurtzite type ZnO structure for all the compositions. The Zn(0.95)Co(0.05)O nanoparticles show diamagnetic behavior at room temperature. However, when Al is co-doped with Co with x = 0.0 to 0.10 in Zn(0.95-x)Co(0.05)Al(x)O, a systematic increase in ferromagnetic moment is observed up to x = 0.07 at 300 K. Above x = 0.07 (e.g. for x = 0.10) a drastic decrease in ferromagnetic nature is observed which is concomitant with the segregation of poorly crystalline Al rich ZnO phase as evidenced from TEM studies. Theoretical studies using density functional calculations on Zn(0.95-x)Co(0.05)Al(x)O suggest that the partial occupancy of S2 states leads to an increased double exchange interaction favoring the ferromagnetic ground states. Such ferromagnetic interactions are favorable beyond a threshold limit. At a high level doping of Al, the exchange splitting is reduced, which suppresses the ferromagnetic ordering.

Stability and toxicity of ZnO quantum dots: Interplay between nanoparticles and bacteria

Energy Technology Data Exchange (ETDEWEB)

Bellanger, Xavier, E-mail: xavier.bellanger@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy (France); Billard, Patrick, E-mail: patrick.billard@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), UMR 7360, Boulevard des Aiguillettes, Faculté des Sciences et Techniques, BP 70239, 54506 Vandoeuvre-lès-Nancy (France); Schneider, Raphaël, E-mail: raphael.schneider@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire Réactions et Génie des Procédés (LRGP), UMR 7274, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France); Balan, Lavinia, E-mail: lavinia.balan@uha.fr [Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361, CNRS, 15 rue Jean Starcky, 68093 Mulhouse (France); Merlin, Christophe, E-mail: christophe.merlin@univ-lorraine.fr [Université de Lorraine and CNRS, Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy (France)

2015-02-11

Graphical abstract: - Highlights: • Dilution of aminosilane-capped ZnO QDs dramatically increases their dissolution. • Bacteria limit Zn{sup 2+} leakage from ZnO QDs in a physiological-dependent process. • Implementation of biosensors for assessing free metal promotes QDs instability. • Dialysis combined to ICP allows studying QDs stability without prior dilution. - Abstract: The toxicity of quantum dots (QDs) has been commonly attributed to the release of metal ions from the core as well as to the production of reactive oxygen species. However, the information related to the stability of the nanoparticles are relatively scarce although this parameter may strongly influence their toxicity. The stability of aminosilane-capped ZnO QDs, here used as model nanoparticles, was investigated by inductively coupled plasma-optical emission spectrometer (ICP-OES) and whole cell biosensors using a dialysis setup to separate the QDs from the leaked Zn{sup 2+} ions. The integrity of the ZnO QDs appeared strongly affected by their dilution in aqueous medium, whereas the nanoparticles were slightly stabilized by bacteria. Our results demonstrate some inadequacy between the implementation and use of whole cell biosensors, and the monitoring of metal release from QDs.

Noble metal nanoparticle-functionalized ZnO nanoflowers for photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide

International Nuclear Information System (INIS)

Hussain, Muhammad; Sun, Hongyu; Karim, Shafqat; Nisar, Amjad; Khan, Maaz; Ul Haq, Anwar; Iqbal, Munawar; Ahmad, Mashkoor

2016-01-01

Flower-like hierarchical Zinc oxide nanostructures synthesized by co-precipitation method have been hydrothermally functionalized with 8 nm Au NPs and 15 nm Ag nanoparticles. The photocatalytic and electrochemical performance of these structures are investigated. XPS studies show that the composite exhibits a strong interaction between noble metal nanoparticles (NPs) and Zinc oxide nanoflowers. The PL spectra exhibit UV emission arising due to near band edge transition and show that the reduced PL intensities of Au–ZnO and Ag–ZnO composites are responsible for improved photocatalytic activity arising due to increase in defects. Moreover, the presence of Au NPs on ZnO surface remarkably enhances photocatalytic activity as compared to Ag–ZnO and pure ZnO due to the higher catalytic activity and stability of Au NPs. On the other hand, Ag–ZnO-modified glassy carbon electrode shows good amperometric response to hydrogen peroxide (H_2O_2), with linear range from 1 to 20 µM, and detection limit of 2.5 µM (S/N = 3). The sensor shows high and reproducible sensitivity of 50.8 μA cm"−"2 μM"−"1 with a fast response less than 3 s and good stability as compared to pure ZnO and Au–ZnO-based sensors. All these results show that noble metal NPs-functionalized ZnO base nanocomposites exhibit great prospects for developing efficient non-enzymatic biosensor and environmental remediators.Graphical abstractZnO nanoflowers functionalized with noble metal nanoparticles enhance photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide.

Noble metal nanoparticle-functionalized ZnO nanoflowers for photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Hussain, Muhammad [PINSTECH, Nanomaterials Research Group, Physics Division (Pakistan); Sun, Hongyu [Tsinghua University, Laboratory of Advanced Materials and The State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering Beijing, National Center for Electron Microscopy (China); Karim, Shafqat; Nisar, Amjad; Khan, Maaz [PINSTECH, Nanomaterials Research Group, Physics Division (Pakistan); Ul Haq, Anwar [PINSTECH, Non-destructive testing Group (Pakistan); Iqbal, Munawar [University of the Punjab, Centre for High Energy Physics (Pakistan); Ahmad, Mashkoor, E-mail: mashkoorahmad2003@yahoo.com [PINSTECH, Nanomaterials Research Group, Physics Division (Pakistan)

2016-04-15

Flower-like hierarchical Zinc oxide nanostructures synthesized by co-precipitation method have been hydrothermally functionalized with 8 nm Au NPs and 15 nm Ag nanoparticles. The photocatalytic and electrochemical performance of these structures are investigated. XPS studies show that the composite exhibits a strong interaction between noble metal nanoparticles (NPs) and Zinc oxide nanoflowers. The PL spectra exhibit UV emission arising due to near band edge transition and show that the reduced PL intensities of Au–ZnO and Ag–ZnO composites are responsible for improved photocatalytic activity arising due to increase in defects. Moreover, the presence of Au NPs on ZnO surface remarkably enhances photocatalytic activity as compared to Ag–ZnO and pure ZnO due to the higher catalytic activity and stability of Au NPs. On the other hand, Ag–ZnO-modified glassy carbon electrode shows good amperometric response to hydrogen peroxide (H{sub 2}O{sub 2}), with linear range from 1 to 20 µM, and detection limit of 2.5 µM (S/N = 3). The sensor shows high and reproducible sensitivity of 50.8 μA cm{sup −2} μM{sup −1} with a fast response less than 3 s and good stability as compared to pure ZnO and Au–ZnO-based sensors. All these results show that noble metal NPs-functionalized ZnO base nanocomposites exhibit great prospects for developing efficient non-enzymatic biosensor and environmental remediators.Graphical abstractZnO nanoflowers functionalized with noble metal nanoparticles enhance photocatalytic degradation of RhB dye and electrochemical sensing of hydrogen peroxide.

Effect of zinc oxide (ZnO) nanoparticles on physiology and steviol glycosides production in micropropagated shoots of Stevia rebaudiana Bertoni.

Science.gov (United States)

Javed, Rabia; Usman, Muhammad; Yücesan, Buhara; Zia, Muhammad; Gürel, Ekrem

2017-01-01

This study aims to address the effects of different concentrations (0, 0.1, 1.0, 10, 100 or 1000 mg L -1 ) of engineered zinc oxide (ZnO) nanoparticles (34 nm in size) on growth parameters, steviol glycosides (rebaudioside A and stevioside) production and antioxidant activities in the tissue culture grown shoots of Stevia rebaudiana Bertoni. The highest percentage of shoot formation (89.6%) at 1 mg L -1 of ZnO nanoparticles concentration suggests a positive influence of ZnO nanoparticles on S. rebaudiana growth as compared to other treatments with or without ZnO nanoparticles. Additionally, HPLC results illustrate a significant enhancement of steviol glycosides (almost doubled as compared to the control) in micropropagated shoots grown under an oxidative stress of 1 mg L -1 of ZnO nanoparticles. This finding is further affirmed by an increased 2,2-diphenyl-1-picryl hydrazyl (DPPH) scavenging activity, total anti-oxidant capacity, total reducing power, total flavonoid content and total phenolic content, with an ascending oxidative pressure and generation of reactive oxygen species (ROS). However, the antioxidant activities, formation of secondary metabolites and the physiological parameters showed a sudden decline after crossing a threshold of 1 mg L -1 concentration of ZnO nanoparticles and falls to a minimum at 1000 mg L -1 , elucidating maximum phytotoxic effect of ZnO nanoparticles at this concentration. This is the first study evaluating both the favorable and adverse effects of ZnO nanoparticles employed to a highly valuable medicinal plant, S. rebaudiana. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Influence of Mg doping on ZnO nanoparticles decorated on graphene oxide (GO) crumpled paper like sheet and its high photo catalytic performance under sunlight

Science.gov (United States)

Labhane, P. K.; Sonawane, S. H.; Sonawane, G. H.; Patil, S. P.; Huse, V. R.

2018-03-01

Mg doped ZnO nanoparticles decorated on graphene oxide (GO) sheets were synthesized by a wet impregnation method. The effect of Mg doping on ZnO and ZnO-GO composite has been evaluated by using x-ray diffraction (XRD), Williamson-Hall Plot (Wsbnd H Plot), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDX). The physical parameters of as-prepared samples were estimated by XRD data. FESEM and HR-TEM images showed the uniform distribution of nanoparticles on GO crumpled paper like sheet. Solar light photocatalytic activities of samples were evaluated spectrophotometrically by the degradation of p-nitrophenol (PNP) and indigo carmine (IC) solution. Mgsbnd ZnO decorated on GO sheets exhibit excellent catalytic efficiency compared to all other prepared samples under identical conditions, degrading PNP and IC nearly 99% within 60 min under sunlight. The effective degradation by Mgsbnd ZnO decorated on GO sheet would be due to extended solar light absorption, enhanced adsorptivity on the composite catalyst surface and efficient charge separation of photo-induced electrons. Finally, plausible mechanism was suggested with the help of scavengers study.

Synthesis of ZnO nanoparticles using a hydrothermal method and a study its optical activity.

Science.gov (United States)

Bharti, Dattatraya B; Bharati, A V

2017-05-01

ZnO nanoparticles (NPs) with a granular morphology were synthesized using a hydrothermal method. Structural analysis revealed that ZnO NPs had a single crystal wurtzite hexagonal structure. Solvent polarity was responsible for varying and controlling their size and morphology. The process was very trouble free and scalable. In addition, it could be used for fundamental studies on tunable morphology formation. This hydrothermal method showed different morphology with different co-surfactants such as a floral-like or wire-like belt sheet structures etc. Based on their surface morphology, the same material had different applications as a catalyst in various organic reactions and also could be used as a photocatalyst and fuel cell, solar cell or in semiconductors etc. X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy and photoluminescence of the resulting product was performed to study its purity, morphology and size, plus its optical properties via measurement of band gap energy and light absorbance. Copyright © 2016 John Wiley & Sons, Ltd.

Antibacterial Composite Layers on Ti: Role of ZnO Nanoparticles

Directory of Open Access Journals (Sweden)

Roguska A.

2016-03-01

Full Text Available Problem of Post-operative infections of implant materials caused by bacterial adhesion to their surfaces is very serious. Enhancement of antibacterial properties is potentially beneficial for biomaterials value. Therefore, the metallic and metallic oxide nanoparticles attract particular attention as antimicrobial factors. The aim of this work was to create nanotubular (NT oxide layers on Ti with the addition of ZnO nanoparticles, designed for antibacterial biomedical coatings. Antimicrobial activities of titanium, TiO2 NT and ZnO/TiO2 NT surfaces were evaluated against bacterial strain typical for orthopaedic infections: S. epidermidis. TiO2 NT alone killed the free bacterial cells significantly but promoted their adhesion to the surfaces. The presence of moderate amount of ZnO nanoparticles significantly reduced the S. epidermidis cells adhesion and viability of bacterial cells in contact with modified surfaces. However, higher amount of loaded nanoZnO showed the reduced antimicrobial properties than the medium amount, suggesting the overdose effect.

Chemical bath deposition of ZnO nanowire-nanoparticle composite electrodes for use in dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Ku, C-H; Wu, J-J [Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

2007-12-19

ZnO nanowire (NW)-layered basic zinc acetate (LBZA)/ZnO nanoparticle (NP) composite electrodes with different NP occupying extents have been synthesized using a simple wet-chemical route for use in dye-sensitized solar cells (DSSCs). By employing mercurochrome as the sensitizer, superior efficiencies ({eta}) of 1.27-2.37% are obtained using the ZnO NW-LBZA/ZnO NP composite electrodes composed of a 5.5 {mu}m thick NW array with different NP occupying extents in comparison with the ZnO NW DSSC ({eta} = 0.45%). It suggests that the ZnO NW-LBZA/ZnO NP composite films which possess a considerable enlarged surface area by NPs growth, without sacrificing electron transport efficiency of single-crystalline ZnO NWs at the same time, are promising photoanodes for use in DSSCs. In addition to the extent of NP occupation, the overall efficiency of the ZnO NW-LBZA/ZnO NP composite DSSC is also influenced by the thickness of the composite film as well as the LBZA fraction and the cracks within the composite. The fraction of LBZA affected by the NP growth period and post-annealing conditions is found to play a crucial role in electron transport through the composite anode. Up to now, a high efficiency DSSC of 3.2% is achieved using a mercurochrome-sensitized and 6.2 {mu}m thick NW-NP composite film.

Biomedical applications of green synthesized Nobel metal nanoparticles.

Science.gov (United States)

Khan, Zia Ul Haq; Khan, Amjad; Chen, Yongmei; Shah, Noor S; Muhammad, Nawshad; Khan, Arif Ullah; Tahir, Kamran; Khan, Faheem Ullah; Murtaza, Behzad; Hassan, Sadaf Ul; Qaisrani, Saeed Ahmad; Wan, Pingyu

2017-08-01

Synthesis of Nobel metal nanoparticles, play a key role in the field of medicine. Plants contain a substantial number of organic constituents, like phenolic compounds and various types of glycosides that help in synthesis of metal nanoparticles. Synthesis of metal nanoparticles by green method is one of the best and environment friendly methods. The major significance of the green synthesis is lack of toxic by-products produced during metal nanoparticle synthesis. The nanoparticles, synthesized by green method show various significant biological activities. Most of the research articles report the synthesized nanoparticles to be active against gram positive and gram negative bacteria. Some of these bacteria include Escherichia coli, Bacillus subtilis, Klebsiella pneumonia and Pseudomonas fluorescens. The synthesized nanoparticles also show significant antifungal activity against Trichophyton simii, Trichophyton mentagrophytes and Trichophyton rubrum as well as different types of cancer cells such as breast cancer cell line. They also exhibit significant antioxidant activity. The activities of these Nobel metal nano-particles mainly depend on the size and shape. The particles of small size with large surface area show good activity in the field of medicine. The synthesized nanoparticles are also active against leishmanial diseases. This research article explores in detail the green synthesis of the nanoparticles and their uses thereof. Copyright © 2017 Elsevier B.V. All rights reserved.

Citrus maxima (Pomelo) juice mediated eco-friendly synthesis of ZnO nanoparticles: Applications to photocatalytic, electrochemical sensor and antibacterial activities

Science.gov (United States)

Pavithra, N. S.; Lingaraju, K.; Raghu, G. K.; Nagaraju, G.

2017-10-01

In the present work, Zinc oxide nanoparticles (ZnO Nps) have been successfully prepared through a simple, effective and low cost solution combustion method using Zn (NO3)2·6H2O as an oxidizer, chakkota (Common name = Pomelo) fruit juice as novel fuel. X-ray diffraction pattern indicates the hexagonal wurtzite structure with average crystallite size of 22 nm. ZnO Nps were characterized with the aid of different spectroscopic techniques such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Photoluminescence and UV-Visible spectroscopy. FTIR shows characteristic ZnO vibrational mode at 393 cm- 1. SEM images show that the particles are agglomerated. TEM image shows the size of the particles are about 10-20 nm. Further, in order to establish practical applicability of the synthesized ZnO Nps, photocatalytic degradation of methylene blue (MB) dye as a model system was studied in presence of UV (665 nm) light. In addition to this, the antibacterial activity was screen against 3 bacterial strains and electrochemical sensor performance towards the quantification of dopamine at nano molar concentrations was also explored.

Synthesis and their enhanced photoelectrochemical performance of ZnO nanoparticle-loaded CuO dandelion heterostructures under solar light

Energy Technology Data Exchange (ETDEWEB)

Dong, Guanying; Du, Bin; Liu, Lei; Zhang, Weiwei; Liang, Yujie; Shi, Honglong; Wang, Wenzhong, E-mail: wzhwangmuc@163.com

2017-03-31

Highlights: • ZnO/CuO nanoparticle/dandelion heterostructures were fabricated for the first time. • ZnO/CuO nanoparticle/dandelion heterostructures show enhanced PEC activity. • ZnO nanoparticle loading contents have significant effect on PEC water splitting. • Interaction, charge transfer and enhanced mechanism of photocatalyst were proposed. • p-n junction drives the photoexcited charges efficient separation. - Abstract: Here we report an easy and large-scale synthesis of three-dimensional (3D) ZnO nanoparticle-loaded CuO dandelion (denoted as n-ZnO/p-CuO nanoparticle/dandelion) heterostructures and their photoelectrochemical (PEC) water splitting under simulated solar light illumination. CuO dandelions were fabricated by a facile and cost-effective chemical strategy, in which the ribbon-like CuO nanoplates were first formed and then assembled into dandelion-like architectures. ZnO nanoparticle-loaded CuO dandelion heterostructures were fabricated by calcining Zn(Ac){sub 2}-loaded CuO dandelions. High resolution transmission electron microscope (HRTEM) studies demonstrate that intimate p-n junction is built between p-CuO and n-ZnO interface. The n-ZnO/p-CuO nanoparticle/dandelion photoelectrodes exhibit significant improvement in PEC water splitting to CuO dandelion photoelectrodes. The correlation between photocurrents and different loading contents of ZnO nanoparticles (NPs) is studied in which the n-ZnO/p-CuO nanoparticle/dandelion heterostructures with loading 4.6 wt% ZnO NPs show higher photocathodic current. The efficient separation of the photogenerated electrons and holes driven by the intimate p-n junction between p-type CuO and n-type ZnO interface is mainly contributed to the enhanced photoanode current. The achieved results in the present study offer a very useful strategy for designing p-n junction photoelectrodes for efficiency and low-cost PEC cells for clean solar hydrogen production.

Hydrothermal Growth of Vertically Aligned ZnO Nanorods Using a Biocomposite Seed Layer of ZnO Nanoparticles.

Science.gov (United States)

Ibupoto, Zafar Hussain; Khun, Kimleang; Eriksson, Martin; AlSalhi, Mohammad; Atif, Muhammad; Ansari, Anees; Willander, Magnus

2013-08-19

Well aligned ZnO nanorods have been prepared by a low temperature aqueous chemical growth method, using a biocomposite seed layer of ZnO nanoparticles prepared in starch and cellulose bio polymers. The effect of different concentrations of biocomposite seed layer on the alignment of ZnO nanorods has been investigated. ZnO nanorods grown on a gold-coated glass substrate have been characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) techniques. These techniques have shown that the ZnO nanorods are well aligned and perpendicular to the substrate, and grown with a high density and uniformity on the substrate. Moreover, ZnO nanorods can be grown with an orientation along the c -axis of the substrate and exhibit a wurtzite crystal structure with a dominant (002) peak in an XRD spectrum and possessed a high crystal quality. A photoluminescence (PL) spectroscopy study of the ZnO nanorods has revealed a conventional near band edge ultraviolet emission, along with emission in the visible part of the electromagnetic spectrum due to defect emission. This study provides an alternative method for the fabrication of well aligned ZnO nanorods. This method can be helpful in improving the performance of devices where alignment plays a significant role.

Hydrothermal Growth of Vertically Aligned ZnO Nanorods Using a Biocomposite Seed Layer of ZnO Nanoparticles

Directory of Open Access Journals (Sweden)

Zafar Hussain Ibupoto

2013-08-01

Full Text Available Well aligned ZnO nanorods have been prepared by a low temperature aqueous chemical growth method, using a biocomposite seed layer of ZnO nanoparticles prepared in starch and cellulose bio polymers. The effect of different concentrations of biocomposite seed layer on the alignment of ZnO nanorods has been investigated. ZnO nanorods grown on a gold-coated glass substrate have been characterized by X-ray diffraction (XRD and field emission scanning electron microscopy (FESEM techniques. These techniques have shown that the ZnO nanorods are well aligned and perpendicular to the substrate, and grown with a high density and uniformity on the substrate. Moreover, ZnO nanorods can be grown with an orientation along the c-axis of the substrate and exhibit a wurtzite crystal structure with a dominant (002 peak in an XRD spectrum and possessed a high crystal quality. A photoluminescence (PL spectroscopy study of the ZnO nanorods has revealed a conventional near band edge ultraviolet emission, along with emission in the visible part of the electromagnetic spectrum due to defect emission. This study provides an alternative method for the fabrication of well aligned ZnO nanorods. This method can be helpful in improving the performance of devices where alignment plays a significant role.

Biogenic synthesized nanoparticles and their applications

Energy Technology Data Exchange (ETDEWEB)

Singh, Abhijeet, E-mail: abhijeet.singh@jaipur.manipal.edu; Sharma, Madan Mohan [Manipal University Jaipur (India)

2016-05-06

In the present scenario, there are growing concerns over the potential impacts of bioengineered nanoparticles in the health sector. However, our understanding of how bioengineered nanoparticles may affect organisms within natural ecosystems, lags far behind our rapidly increasing ability to engineer novel nanoparticles. To date, research on the biological impacts of bioengineered nanoparticles has primarily consisted of controlled lab studies of model organisms with single species in culture media. Here, we described a cost effective and environment friendly technique for green synthesis of silver nanoparticles. Silver nanoparticles were successfully synthesized from 1 mM AgNO{sub 3} via a green synthesis process using leaf extract as reducing as well as capping agent. Nanoparticles were characterized with the help of UV–vis absorption spectroscopy, X-ray diffraction and TEM analysis which revealed the size of nanoparticles of 30-40 nm size. Further the nanoparticles synthesized by green route are found highly toxic against pathogenic bacteria and plant pathogenic fungi viz. Escherichia coli, Pseudomonas syringae and Sclerotiniasclerotiorum. The most important outcome of this work will be the development of value-added products and protection of human health from pathogens viz., bacteria, virus, fungi etc.

Biogenic synthesized nanoparticles and their applications

International Nuclear Information System (INIS)

Singh, Abhijeet; Sharma, Madan Mohan

2016-01-01

In the present scenario, there are growing concerns over the potential impacts of bioengineered nanoparticles in the health sector. However, our understanding of how bioengineered nanoparticles may affect organisms within natural ecosystems, lags far behind our rapidly increasing ability to engineer novel nanoparticles. To date, research on the biological impacts of bioengineered nanoparticles has primarily consisted of controlled lab studies of model organisms with single species in culture media. Here, we described a cost effective and environment friendly technique for green synthesis of silver nanoparticles. Silver nanoparticles were successfully synthesized from 1 mM AgNO_3 via a green synthesis process using leaf extract as reducing as well as capping agent. Nanoparticles were characterized with the help of UV–vis absorption spectroscopy, X-ray diffraction and TEM analysis which revealed the size of nanoparticles of 30-40 nm size. Further the nanoparticles synthesized by green route are found highly toxic against pathogenic bacteria and plant pathogenic fungi viz. Escherichia coli, Pseudomonas syringae and Sclerotiniasclerotiorum. The most important outcome of this work will be the development of value-added products and protection of human health from pathogens viz., bacteria, virus, fungi etc.

Use of chemically synthesized ZnO thin film as a liquefied petroleum gas sensor

International Nuclear Information System (INIS)

Shinde, V.R.; Gujar, T.P.; Lokhande, C.D.; Mane, R.S.; Han, Sung-Hwan

2007-01-01

Liquefied petroleum gas (LPG) sensing properties of ZnO thin films consisting of sub-micron rods synthesized by chemical bath deposition (CBD) method are presented in depth. The scanning electron microscopy observation reveals that ZnO sub-micron rods are of hexagonal in phase grown perpendicular to the substrate surface. Due to large surface area, the ZnO thin films of sub-micron rods were sensitive to the explosive LPG, which was studied for different time depositions and for different operating temperatures. The maximum response of 28% at 673 K was recorded under the exposure of 10% of lower explosive level (LEL) of LPG. The ZnO thin films of sub-micron rods exhibited good sensitivity and rapid response-recovery characteristics towards LPG

Green synthesis and characterization of zinc oxide nanoparticle using insulin plant (Costus pictus D. Don) and investigation of its antimicrobial as well as anticancer activities

Science.gov (United States)

Suresh, Joghee; Pradheesh, Ganeshan; Alexramani, Vincent; Sundrarajan, Mahalingam; Hong, Sun Ig

2018-03-01

In this work we aim to synthesize biocompatible ZnO nanoparticles from the zinc nitrate via green process using leaf extracts of the Costus pictus D. Don medicinal plant. FTIR studies confirm the presence of biomolecules and metal oxides. X-ray diffraction (XRD) structural analysis reveals the formation of pure hexagonal phase structures of ZnO nanoparticles. The surface morphologies of ZnO nanoparticles observed under a scanning electron microscope (SEM) suggest that most ZnO crystallites are hexagonal. EDX analysis confirms the presence of primarily zinc and oxygen. TEM images show that biosynthesized zinc oxide nanoparticles are hexagonal and spherical. The plausible formation mechanisms of zinc oxide nanoparticles are also predicted. The biosynthesized zinc oxide nanoparticles exhibit strong antimicrobial behavior against bacterial and fungal species when employing the agar diffusion method. Synthesized ZnO nanoparticles exhibit anticancer activity against Daltons lymphoma ascites (DLA) cells as well as antimicrobial activity against some bacterial and fungal strains.

ZnO nanoparticles obtained by ball milling technique: Structural, micro-structure, optical and photo-catalytic properties

Energy Technology Data Exchange (ETDEWEB)

Balamurugan, S., E-mail: scandium.chemistry@gmail.com; Joy, Josny; Godwin, M. Anto; Selvamani, S.; Raja, T. S. Gokul [Advanced Nanomaterials Research Laboratory, Department of Nanotechnology, Noorul Islam Centre for Higher Education, Thuckalay, Kumaracoil - 629 180 (India)

2016-05-23

The ZnO nanoparticles were obtained by ball milling of commercial grade ZnO powder at 250 rpm for 20 h and studied their structural, micro-structure, optical and photo-catalytic properties. Due to ball milling significant decrease in lattice parameters and average crystalline size is noticed for the as-milled ZnO nano powder. The HRSEM images of the as-milled powder consist of agglomerated fine spherical nanoparticles in the range of ~10-20 nm. The room temperature PL spectrum of as-milled ZnO nano powder excited under 320 nm reveals two emission bands at ~406 nm (violet emission) and ~639 nm (green emission). Interestingly about 98 % of photo degradation of methylene (MB) by the ZnO catalyst is achieved at 100 minutes of solar light irradiation.

Green synthesis, characterization and antimicrobial activities of zinc oxide nanoparticles from the leaf extract of Azadirachta indica (L.)

Energy Technology Data Exchange (ETDEWEB)

Elumalai, K. [Department of Physics, Annamalai University, Annamalai Nagar 608002 (India); Velmurugan, S., E-mail: drvelmurganphy@gmail.com [Department of Engineering Physics (FEAT), Annamalai University, Annamalai Nagar 608 002 (India)

2015-08-01

Graphical abstract: - Highlights: • Phenolic acid and flavonoid compounds play a major role in bioreduction reaction confirmed by FT-IR. • PL spectrum identified peaks were located in the range of the blue-violet spectrum. • XRD pattern confirmed ZnO hexagonal phase (wurtzite structure). • The result of (AFM) images depicted polycrystalline with porous nature of ZnO NPs. • Antimicrobial activities of green synthesized ZnO NPs were more potent than Bare ZnO and leaf of A. indica. - Abstract: The synthesis of metal and semiconductor nanoparticles is an expanding research area due to the potential applications in the development of novel technologies. Especially, biologically synthesized nanomaterial has become an important branch of nanotechnology. The present work, described the synthesis of zinc oxide nanoparticles (ZnO NPs) using leaf aqueous extract of Azadirachta indica (L.) and its antimicrobial activities. The nanoparticles was obtain characterized by UV–Vis spectroscopy, Photoluminescence (PL), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) analysis, Energy dispersive X-ray analysis (EDAX), Field emission scanning electron microscopy (FESEM) and Atomic force microscope (AFM) analysis. In this study we also investigated antimicrobial activity of green synthesized ZnO NPs. The results depicted concentration of ZnO NPs was increased (50, 100, 200 μg/mL) and also increase in antimicrobial activities was due to the increase of H{sub 2}O{sub 2} concentration from the surface of ZnO. However, green synthesized ZnO NPs was more potent than Bare ZnO and leaf of A. indica. Finally concluded the zinc oxide nanoparticles exhibited an interesting antimicrobial activity with both Gram positive and Gram negative bacterial and yeast at micromolar concentration.

Structural Characterization and Magnetic Properties of Undoped and Ti-Doped ZnO Nanoparticles Prepared by Modified Oxalate Route

Directory of Open Access Journals (Sweden)

Ekane Peter Etape

2018-01-01

Full Text Available Ti-doped zinc oxide and pure zinc oxide nanoparticles were synthesized by a modified oxalate route using Averrhoa carambola fruit juice as a natural source of oxalate. The characteristics of the precursors have been investigated by FTIR, TGA, and XRD. The results from the investigation revealed that the precursors are zinc oxalate and Ti-doped zinc oxalate which readily decompose at 450°C. The as-prepared precursors were calcined at 450°C for 4 hours, and the decomposition products have been characterized by XRD, SEM, EDX, and VSM. XRD results revealed crystallinity with hexagonal wurtzite structure, while the average grain size was found to be 26 nm for Ti-doped ZnO and 29 nm for ZnO, using calculations based on Debye-Scherrer equation. Furthermore, the morphological studies by SEM showed particle agglomeration, while the presence of Ti3+ in the zinc oxide lattice is indicated by EDS analysis. Finally the hysteresis loop from VSM results shows that Ti-doped ZnO exhibits ferromagnetism.

Carrier transport in flexible organic bistable devices of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) polymer layer

International Nuclear Information System (INIS)

Son, Dong-Ick; Park, Dong-Hee; Choi, Won Kook; Cho, Sung-Hwan; Kim, Won-Tae; Kim, Tae Whan

2009-01-01

The bistable effects of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) (PMMA) polymer single layer by using flexible polyethylene terephthalate (PET) substrates were investigated. Transmission electron microscopy (TEM) images revealed that ZnO nanoparticles were formed inside the PMMA polymer layer. Current-voltage (I-V) measurement on the Al/ZnO nanoparticles embedded in an insulating PMMA polymer layer/ITO/PET structures at 300 K showed a nonvolatile electrical bistability behavior with a flat-band voltage shift due to the existence of the ZnO nanoparticles, indicative of trapping, storing, and emission of charges in the electronic states of the ZnO nanoparticles. The carrier transport mechanism of the bistable behavior for the fabricated organic bistable device (OBD) structures is described on the basis of the I-V results by analyzing the effect of space charge.

Insights into post-annealing and silver doping effects on the internal microstructure of ZnO nanoparticles through X-ray diffraction probe

Science.gov (United States)

Obeydavi, Ali; Dastafkan, Kamran; Rahimi, Mohammad; Ghadam Dezfouli, Mohammad Amin

2017-07-01

ZnO nanoparticles were synthesized via Pechini method at various post-annealing temperatures (400°, 500°, and 600 °C) and silver doping concentrations (Zn:Ag molar ratios of 30, 20, and 10). Multifarious microstructural features including crystallite size, size-strain based broadening, residual stress, preferential orientation, crystallinity degree, lattice parameters, unit cell variation, and stacking fault probability were surveyed through phase analysis, Williamson-Hall plot, texture coefficient and unit cell calculations. X-ray probing verified good crystallinity with a hexagonal close pack Wurtzite morphology. Williamson-Hall analysis exhibited distributions of crystallite size and microstrain as well as their contributions on the line broadening of the host ZnO and guest Ag phases upon annealing-doping treatments. Textural analysis revealed the alteration in anisotropic crystallinity of the host phase and transformation of the preferred directions, (100) and (101), as function of annealing-doping processes. Besides, while guest Ag phase was shown to be polycrystalline with randomly orientated crystals at moderate concentration with respect to thermal treatment, preferential orientation went through a major change, (220) to (111), with increment in Ag loadings. Under identical synthetic conditions, the distinction in the lattice constants and unit cell variation between pure and doped ZnO nanoparticles was enforced and results verified major impressionability via annealing and doping factors.

Functionalized ZnO Nanoparticles with Gallic Acid for Antioxidant and Antibacterial Activity against Methicillin-Resistant S. aureus

Directory of Open Access Journals (Sweden)

Joomin Lee

2017-11-01

Full Text Available In this study, we report a new multifunctional nanoparticle with antioxidative and antibacterial activities in vitro. ZnO@GA nanoparticles were fabricated by coordinated covalent bonding of the antioxidant gallic acid (GA on the surface of ZnO nanoparticles. This addition imparts both antioxidant activity and high affinity for the bacterial cell membrane. Antioxidative activities at various concentrations were evaluated using a 2,2′-azino-bis(ethylbenzthiazoline-6-sulfonic acid (ABTS radical scavenging method. Antibacterial activities were evaluated against Gram-positive bacteria (Staphylococcus aureus: S. aureus, including several strains of methicillin-resistant S. aureus (MRSA, and Gram-negative bacteria (Escherichia coli. The functionalized ZnO@GA nanoparticles showed good antioxidative activity (69.71%, and the bactericidal activity of these nanoparticles was also increased compared to that of non-functionalized ZnO nanoparticles, with particularly effective inhibition and high selectivity for MRSA strains. The results indicate that multifunctional ZnO nanoparticles conjugated to GA molecules via a simple surface modification process displaying both antioxidant and antibacterial activity, suggesting a possibility to use it as an antibacterial agent for removing MRSA.

Morphological, Structural, and Electrical Characterization of Sol-Gel-Synthesized ZnO Nano rods

International Nuclear Information System (INIS)

Kashif, M.; Hashim, U.; Foo, K.L.; Ali, M.E.; Ali, M.E.; Ali, S.M.U.

2013-01-01

ZnO nano rods were grown on thermally oxidized p-type silicon substrate using sol-gel method. The SEM image revealed high-density, well-aligned, and perpendicular ZnO nano rods on the oxidized silicon substrate. The XRD profile confirmed the c-axis orientation of the nano rods. PL measurements showed the synthesized ZnO nano rods have strong ultraviolet (UV) emission. The electrical characterization was performed using interdigitated silver electrodes to investigate the stability in the current flow of the fabricated device under different ultraviolet (UV) exposure times. It was notified that a stable current flow was observed after 60 min of UV exposure. The determination of stable current flow after UV exposure is necessary for UV-based gas sensing and optoelectronic devices.

Study on magnetite nanoparticles synthesized by chemical method

International Nuclear Information System (INIS)

Pei Wenli; Kumada, H.; Natusme, T.; Saito, H.; Ishio, S.

2007-01-01

Magnetite nanoparticles with controlled size were synthesized by chemical method. Higher deposition temperature and a rapid-raising temperature procedure are favorable to particle size distribution and fabrication of monodisperse nanoparticles. The larger nanoparticles can be synthesized by the two-step method. The large nanoparticle (up to 25 nm) without agglomeration was successfully produced. The saturation magnetization of 11 nm magnetite particles was 45 emu/g at room temperature, which is smaller than that of bulk magnetite due to surface effect. Hysteresis of the magnetite nanoparticle was very small, indicating superparamagnetic behavior. The magnetic domains of the 11 nm magnetite nanoparticles were successfully observed by MFM

The effect of ZnO nanoparticles on improved oil recovery in spontaneous imbibition mechanism of heavy oil production

Science.gov (United States)

Tajmiri, M.; Ehsani, M. R.; Mousavi, S. M.; Roayaei, E.; Emadi, A.

2015-07-01

Spontaneous imbibition (SI) gets a controversial subject in oil- wet carbonate reservoirs. The new concept of nanoparticles applications in an EOR area have been recently raised by researches about oil viscosity reduction and generate emulsion without surfactant. But a lot of questions have been remained about which nanoparticles can alter wettability from oil- wet to water- wet to improve oil recovery. This study introduces the new idea of adding ZnO nanoparticles (0.2%wt concentration) by experimental work on oil recovery. The main goals of this research were to prove that ZnO nanoparticles have the ability to reduce viscosity and also alter wettability. The ultimate objective was to determine the potential of these nanoparticles to imbibe into and displace oil. Through the use of Amott- cell, laboratory tests were conducted in two experiments on four cylindrical core samples (three sandstones and one carbonate) were taken from real Iranian heavy oil reservoir. In the first experiment, core samples were saturated by crude oil and in the second experiment, nanoparticles were flooding into core samples and then saturated by crude oil for about two weeks and after that they were immersed in distilled water and the amount of recovery was monitored during 30 days for both tests. We expected that ZnO nanoparticles decreased the surface tension which reduced the capillary forces through SI and wettability alteration took place towards a more water-wet system and caused the oil relative permeability to increase which dominated the gravitational forces to pull out the oil. Our results proved this expectation from ZnO nanoparticles clearly because carbonate core was oil- wet and the capillary pressure was high and negative to push water into the core so the original oil in place (OOIP) was zero whereas by adding ZnO nanoparticles OOIP was increased to 8.89%. SI yielded recovery values from 17.3, 2 and 15 without nanoparticles to 20.68, 17.57 and 36.2 % OOIP with

CNT supported Mn-doped ZnO nanoparticles: simple synthesis and improved photocatalytic activity for degradation of malachite green dye under visible light

Science.gov (United States)

Mohamed, R. M.; Shawky, Ahmed

2018-03-01

Hexagonal ZnO nanoparticles doped with Mn and supported with a minor amount of carbon nanotubes (CNTs) were synthesized through a simple coprecipitation-ultrasonication process with high yield. The effect of Mn doping, as well as CNTs addition on structure, surface morphology and texture, optical and electronic properties, was studied. We found that just 1% Mn doping and 1% CNT addition on ZnO showed the best crystallinity, highest surface area, improved visible light absorption, and a lowest estimated band gap of 2.6 eV with minimum charge recombination as revealed from photoluminescence spectra. The application of the optimum composition of the synthesized sample for the photodegradation of malachite green dye showed enhanced photocatalytic activity > 95% under visible light irradiation within 120 min at a minimum dosage of 0.1 g L-1 without any using of hole scavenger or changing the pH. This work highlighting the humble preparation procedure and develops photocatalysis research for real industrial applications.

Investigation on Fe-doped ZnO nanostructures prepared by a chemical route

Energy Technology Data Exchange (ETDEWEB)

Mishra, A.K. [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700098 (India); Das, D., E-mail: ddas@alpha.iuc.res.in [UGC-DAE Consortium for Scientific Research, Kolkata Centre III/LB-8, Bidhannagar, Kolkata 700098 (India)

2010-07-25

Zn{sub 1-x}Fe{sub x}O (x = 0.03, 0.05 and 0.07) nanoparticles synthesized by a chemical route were characterized by different techniques. The structural characterization by XRD and TEM confirmed the phase purity of the samples and indicated a reduction in particle size with increase in the dopant (Fe) concentration in ZnO. The optical characterization of the nanoparticles by FTIR, PL and UV-visible spectroscopy confirmed the formation of wurtzite structure and incorporation of Fe in the ZnO lattice. Magnetization measurements by VSM and Faraday balance techniques indicate presence of room temperature ferromagnetism in the Fe-doped ZnO samples. Local environment around the Fe atoms has been probed by {sup 57}Fe Moessbauer spectroscopy and the measured isomer shifts confirmed the charge state of iron as Fe{sup 3+}. Positron annihilation lifetime spectroscopy (PALS) measurements confirm the presence of cation vacancies in the nanoparticles and indicate a reduction of overall defect concentration with incorporation of Fe atoms in the ZnO structure.

An efficient method for the synthesis of photo catalytically active ZnO nanoparticles by a gel-combustion method for the photo-degradation of Caffeine

Directory of Open Access Journals (Sweden)

Rajesha Bedre Jagannatha

2017-01-01

Full Text Available In this study, Zinc oxide nanoparticles were synthesized by gel-combustion method using a novel bio-fuel tapioca starch pearls, derived from the tubers of Mannihot esculenta, to investigate the photocatalytic degradation of ccaffeine. The ZnO photocatalyst was characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and UV-visible spectroscopy. X-ray diffractometry result for the ZnO nanoparticles exhibit normal crystalline phase features. All observed peaks can be indexed to the pure hexagonal wurtzite crystal structures. There are no other impurities in the diffraction peak. In addition, SEM measurement shows that most of the nanoparticles are spongy and spherical in shape and fairly mono dispersed. A significant degradation of the Caffeine was observed when the catalyst was added into the solution even without the UV light exposure. In addition, the photo degradation increaseds with the photocatalyst loading. Besides the photocatalyst loading, the effect of some parameters on the photo degradation efficiency such as initial concentration and pH were also studied.

Mn-doped ZnO nanocrystals synthesized by sonochemical method: Structural, photoluminescence, and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Othman, A.A., E-mail: aaelho@yahoo.com [Assiut University, Faculty of Science, Department of Physics, Assiut 71516 (Egypt); Osman, M.A. [Assiut University, Faculty of Science, Department of Physics, Assiut 71516 (Egypt); Ibrahim, E.M.M. [Sohag University, Faculty of Science, Department of Physics, Sohag 82524 (Egypt); Ali, Manar A.; Abd-Elrahim, A.G. [Assiut University, Faculty of Science, Department of Physics, Assiut 71516 (Egypt)

2017-05-15

Highlights: • Mn-doped ZnO nanostructures were synthesized by the sonochemical method. • Structural, morphological, optical, photoluminescence and magnetic properties were investigated. • Mn-doped ZnO nanostructures reveal a blue shift of the optical band gap. • Photoluminescence spectra of Mn-doped ZnO nanostructures show quenching in the emission intensity. • Mn-doped ZnO nanostructures exhibit ferromagnetic ordering at room temperature. - Abstract: This work reports the synthesis of Mn-doped ZnO nanostructures using ice-bath assisted sonochemical technique. The impact of Mn-doping on structural, morphological, optical, and magnetic properties of ZnO nanostructures is studied. The morphological study shows that the lower doped samples possess mixtures of nanosheets and nanorods while the increase in Mn content leads to improvement of an anisotropic growth in a preferable orientation to form well-defined edge rods at Mn content of 0.04. UV–vis absorption spectra show that the exciton peak in the UV region is blue shifted due to Mn incorporation into the ZnO lattice. Doping ZnO with Mn ions leads to a reduction in the PL intensity due to a creation of more non-radiative recombination centers. The magnetic measurements show that the Mn-doped ZnO nanostructures exhibit ferromagnetic ordering at room temperature, as well as variation of the Mn content can significantly affect the ferromagnetic behavior of the samples.

Local piezoelectric response of ZnO nanoparticles embedded in a photosensitive polymer

Energy Technology Data Exchange (ETDEWEB)

Prashanthi, K.; Zhang, H.; Thundat, T. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta (Canada); Ramgopal Rao, V. [Department of Electrical Engineering, Indian Institute of Technology, Bombay, Mumbai (India)

2012-02-15

Local piezoelectric properties of ZnO nanoparticles (NPs) embedded in a photo-epoxy polymer are investigated by piezoresponse force microscopy (PFM). Integrating ZnO NPs into a photosensitive SU-8 polymer matrix not only retains the highly desired piezoelectric properties of the ZnO, but also preserves photosensitivity and optical transparency of the SU-8 polymer. These results have strong implications for simple photolithography based low-cost fabrication of piezoelectric microelectromechanicalsystems (MEMS) and nanoelectromechanicalsystems (NEMS) in both sensing and energy harvesting applications. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Vertically aligned ZnO nanorods via self-assembled spray pyrolyzed nanoparticles for dye-sensitized solar cells

International Nuclear Information System (INIS)

Dwivedi, Charu; Dutta, V

2012-01-01

Well-aligned zinc oxide (ZnO) nanorods are fabricated on indium-tin-oxide (ITO) coated glass substrates via self-assembly of ZnO nanoparticles created using continuous spray pyrolysis (CoSP) technique. The method involves pre-treatment by dip-coating the substrate with a solution comprising of zinc salt for creating a seed layer, and then spray-pyrolyzed ZnO nanoparticles self-assemble on the pre-treated substrate. The effect of the substrate pre-treatment and the deposition time (t dep ) of nanoparticles is investigated. The results show that the substrate pre-treatment influences the growth of ZnO nanorods which are absent without the pre-treatment. Nanoparticle collection and nanorod growth on different substrates are done simultaneously. The thin films of as-grown nanorods are used as photoelectrode materials to fabricate dye-sensitized solar cells (DSSCs) and the effect of nanorods grown for different times has been studied. The best performance with this cell structure is found for the layer with t dep =15 min, which showed a conversion efficiency of 1.77% for the cell area of 0.25 cm 2

The Effect of SiO2 Shell on the Suppression of Photocatalytic Activity of TiO2 and ZnO Nanoparticles

International Nuclear Information System (INIS)

Lee, Min Hee; Lee, Choon Soo; Patil, Umakant Mahadev; Kochuveedu, Saji Thomas

2012-01-01

In this study, we investigate the potential use of TiO 2 SiO 2 and ZnO SiO 2 core/shell nanoparticles (NPs) as effective UV shielding agent. In the typical synthesis, SiO 2 was coated over different types of TiO 2 (anatase and rutile) and ZnO by sol-gel method. The synthesized TiO 2 SiO 2 and ZnO SiO 2 Nps were characterized by UV-Vis, XRD, Sem and TEM. The UV-vis absorbance and transmittance spectra of core shell NPs showed an efficient blocking effect in the UV region and more than 90% transmittance in the visible region. XRD and SAED studies confirmed the formation of amorphous SiO 2 coated over the TiO 2 and ZnO NPs. The FESEM and TEM images shows that coating of SiO 2 over the surface of anatase, rutile TiO 2 and ZnO NPs resulted in the increase in particle size by ∼30 nm. In order to study the UV light shielding capability of the samples, photocatalytic degradation of methylene blue dye on TiO 2 SiO 2 and ZnO SiO 2 NPs was performed. Photocatalytic activity for both types of TiO 2 NPs was partially suppressed. In comparison, the photocatalytic activity of ZnO almost vanished after the SiO 2 coating

Synthesis Al complex and investigating effect of doped ZnO nanoparticles in the electrical and optical efficiency of OLEDS

Science.gov (United States)

Shahedi, Zahra; Jafari, Mohammad Reza

2017-01-01

In this study, an organometallic complex based on aluminum ions is synthesized. And it is utilized as fluorescent material in the organic light-emitting diodes (OLEDs). The synthesized complex was characterized using XRD, UV-Vis, FT-IR as well as PL spectroscopy analyses. The energy levels of Al complex were determined by cyclic voltammetry measurements. Then, the effects of ZnO nanoparticles (NPs) of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS, on the electrical and optical performance of the organic light-emitting diodes have been investigated. For this purpose, two samples containing ITO/PEDOT:PSS/PVK/Alq3/PBD/Al with two different concentration and two samples containing ITO/PEDOT:PSS:ZnO/PVK/Alq3/PBD/Al with two different concentration were prepared. Then, hole transport, electron transport and emissive layers were deposited by the spin coating method and the cathode layer (Al) was deposited by the thermal evaporation method. The OLED simulation was also done by constructing the model and choosing appropriate parameters. Then, the experimental data were collected and the results interpreted both qualitatively and quantitatively. The results of the simulations were compared with experimental data of the J-V spectra. Comparing experimental data and simulation results showed that the electrical and optical efficiency of the samples with ZnO NPs is appreciably higher than the samples without ZnO NPs.

Comparative studies on Indian traditional nanomedicine Yashadha Bhasma and zinc oxide nanoparticles for anti-diabetic activity

Science.gov (United States)

Durgalakshmi, D.; Ajay Rakkesh, R.; Bhargavi Ram, T.; Balakumar, S.

2017-07-01

Diabetes mellitus is the most common endocrine disorder due to carbohydrate metabolism. Also, zinc and its supplements have been used in Indian traditional medicines for treating urinary tract infections. In this work, an attempt has been made to compare the properties of ‘Yashadha Bhasma’ a traditional ayurvedic ZnO supplement for diabetic treatment with the laboratory-synthesized ZnO nanoparticles. The nano-sized ZnO particles are synthesized using co-precipitation method and calcined at 400 °C for further purification. Confirmation of ZnO and presence of Ca and K elements additional to Zn in Yashadha Bhasma is confirmed from XPS. The morphology of ZnO is found to be spherical with average diameter of 15 nm. TEM results show that ZnO rods of Yashadha Bhasma are porous and non-uniform. Glucose degradation studies revealed good performance with ZnO nanoparticles with 80% degradation occurring within 15 min itself. Antibacterial studies also performed well establishing efficacy of ZnO nanoparticles against both gram-positive and gram-negative bacterial strains, thereby establishing suitable material for treating diabetes mellitus and also curing bacterial wound infections arising due to diabetes mellitus.

ZnO Nanowires Synthesized by Vapor Phase Transport Deposition on Transparent Oxide Substrates

Directory of Open Access Journals (Sweden)

Taylor Curtis

2010-01-01

Full Text Available Abstract Zinc oxide nanowires have been synthesized without using metal catalyst seed layers on fluorine-doped tin oxide (FTO substrates by a modified vapor phase transport deposition process using a double-tube reactor. The unique reactor configuration creates a Zn-rich vapor environment that facilitates formation and growth of zinc oxide nanoparticles and wires (20–80 nm in diameter, up to 6 μm in length, density <40 nm apart at substrate temperatures down to 300°C. Electron microscopy and other characterization techniques show nanowires with distinct morphologies when grown under different conditions. The effect of reaction parameters including reaction time, temperature, and carrier gas flow rate on the size, morphology, crystalline structure, and density of ZnO nanowires has been investigated. The nanowires grown by this method have a diameter, length, and density appropriate for use in fabricating hybrid polymer/metal oxide nanostructure solar cells. For example, it is preferable to have nanowires no more than 40 nm apart to minimize exciton recombination in polymer solar cells.

Non-vacuum, single-step conductive transparent ZnO patterning by ultra-short pulsed laser annealing of solution-deposited nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Lee, Daeho; Pan, Heng; Kim, Eunpa; Grigoropoulos, Costas P. [University of California, Department of Mechanical Engineering, Berkeley, CA (United States); Ko, Seung Hwan [Korea Advanced Institute of Science and Technology (KAIST), Department of Mechanical Engineering, Daejeon (Korea, Republic of); Park, Hee K. [AppliFlex LLC, Sunnyvale, CA (United States)

2012-04-15

A solution-processable, high-concentration transparent ZnO nanoparticle (NP) solution was successfully synthesized in a new process. A highly transparent ZnO thin film was fabricated by spin coating without vacuum deposition. Subsequent ultra-short-pulsed laser annealing at room temperature was performed to change the film properties without using a blanket high temperature heating process. Although the as-deposited NP thin film was not electrically conductive, laser annealing imparted a large conductivity increase and furthermore enabled selective annealing to write conductive patterns directly on the NP thin film without a photolithographic process. Conductivity enhancement could be obtained by altering the laser annealing parameters. Parametric studies including the sheet resistance and optical transmittance of the annealed ZnO NP thin film were conducted for various laser powers, scanning speeds and background gas conditions. The lowest resistivity from laser-annealed ZnO thin film was about 4.75 x 10{sup -2} {omega} cm, exhibiting a factor of 10{sup 5} higher conductivity than the previously reported furnace-annealed ZnO NP film and is even comparable to that of vacuum-deposited, impurity-doped ZnO films within a factor of 10. The process developed in this work was applied to the fabrication of a thin film transistor (TFT) device that showed enhanced performance compared with furnace-annealed devices. A ZnO TFT performance test revealed that by just changing the laser parameters, the solution-deposited ZnO thin film can also perform as a semiconductor, demonstrating that laser annealing offers tunability of ZnO thin film properties for both transparent conductors and semiconductors. (orig.)

Dye-sensitized solar cells with ZnO nanoparticles fabricated at low temperature

Energy Technology Data Exchange (ETDEWEB)

Cho, Sungjae; Moon, Byungjoon; Son, Dongick [Korea Institute of Science and Technology, Wanju (Korea, Republic of); Kwon, Byoungwook; Choi, Wonkook [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

2014-11-15

The authors investigated the microstructural and the electrical properties of ZnO based dyesensitized solar cells (DSSCs) fabricated using a low-temperature-processed(200 .deg. C) dye-sensitized ZnO-nanoparticle thin film and a Pt catalyst deposited on ITO/glass by using RF magnetron sputtering. A hydropolymer containing PEG (poly(ethylene glycol)) and PEO (poly ethylene oxide) was used to make uniformly-distributed ZnO nanoparticle layer that form a nano-porous ZnO network after heat treatment and was then dye sensitized and sandwiched between two electrodes in an electrolyte to make a DSSC device. The highest measured parameters, the short circuit current density (J{sub sc}), the open circuit potential(V{sub oc}), the fill factor(FF), and the power conversion efficiency (η), of the DSSC fabricated under optimized conditions were observed to be 4.93 mA/cm{sup 2}, 0.56 V, 0.40, and 1.12%, respectively.

Biosynthesis of silver nanoparticles synthesized by Aspergillus

Indian Academy of Sciences (India)

In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

Examination of Zinc Oxide Nanoparticles as a Fluorescent Fingerprint Detection Powder

International Nuclear Information System (INIS)

Tun Tun Lin

2010-12-01

Detection of latent fingerprint was performed using zinc oxide nanoparticles which were produced by simple and efficient method in aqueous media from zinc nitrate. Synthesized ZnO nanoparticles were characterized by XRD, SEM and AFM for ZnO purification and particle size examination. In this paper an effort has been made to compare the results of using ZnO nanoparticles and conventional fingerprint powders such as ZnO bulk powder, CaO, TiO2, printer toner powder and graphite. Fingerprints on different materials were also examined by the use of ZnO and Graphite powder, which is currently used in the Central Intelligence Department of Myanmar Police Force.From this research, it was observed that zinc oxide nanoparticles powder produced a much clearer picture of the fingerprints, compared to conventional powders and it has very good quality at sticking to the fingerprint residue but not to the background surface.

Determining the morphology of polystyrene-block-poly(2-vinylpyridine) micellar reactors for ZnO nanoparticle synthesis.

Science.gov (United States)

El-Atwani, Osman; El-Atwani, Osman C; Aytun, Taner; Mutaf, Omer Faruk; Srot, Vesna; van Aken, Peter A; Ow-Yang, Cleva W

2010-05-18

We report the use of reverse PS-b-P2VP diblock copolymer micelles as true nanoscale-sized reactor vessels to synthesize ZnO nanoparticles. The reverse micelles were formed in toluene and then sequentially loaded with zinc acetate dihydrate and tetramethylammonium hydroxide reactants. Moreover, high spatial resolution Z-contrast imaging and EDX spectroscopy techniques were used to confirm the segregation of the Zn cation to the core of the loaded micelles. Determining the chemical distribution with high nanoscale spatial resolution is shown to complement the less direct characterization by AFM, DLS and FTIR, thus demonstrating broader implications for the characterization of hybrid nanocomposite systems.

Gum Tragacanth-Mediated Synthesis of Nanocrystalline ZnO Powder for Use in Varistors

Science.gov (United States)

Liu, Ting-Ting; Wang, Mao-Hua; Su, Hang; Chen, Xi; Chen, Chao; Zhang, Ruo-Chen

2015-10-01

Zinc oxide nanopowders were synthesized by a sol-gel method with gum tragacanth and zinc nitrate as raw materials. Gum tragacanth was used as stabilizer to control the mobility of zinc cations and the growth of the nanopowders. Thermo-gravimetric analysis, x-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, and scanning electron microscopy were used to characterize the as-prepared samples. Zinc oxide (ZnO) nanoparticles calcined at different temperatures had a hexagonal wurtzite structure with average particle size ranging from 32.29 nm to 42.83 nm. The crystallinity of ZnO nanoparticles was improved by increasing the calcination temperature. The density of ZnO varistor ceramics sintered at 1150°C for 2 h in air was 5.46 g/cm3, which was 97.5% of the theoretical density, their breakdown voltage was 4572 V/cm, and their nonlinear coefficient was ~16.8. This method can be used as an excellent alternative method for synthesis of ZnO nanoparticles with a plant extract as a raw material. Our experimental results show our method had the advantage of improving the electrical performance of ZnO varistors.

Effects of PLA Film Incorporated with ZnO Nanoparticle on the Quality Attributes of Fresh-Cut Apple.

Science.gov (United States)

Li, Wenhui; Li, Lin; Cao, Yun; Lan, Tianqing; Chen, Haiyan; Qin, Yuyue

2017-07-31

A novel nanopackaging film was synthesized by incorporating ZnO nanoparticles into a poly-lactic acid (PLA) matrix, and its effect on the quality of fresh-cut apple during the period of preservation was investigated at 4 ± 1 °C for 14 days. Six wt % cinnamaldehyde was added into the nano-blend film. Scanning electron microscope (SEM) analysis showed a rougher cross-section of the nano-blend films and an X-ray diffraction (XRD) was carried out to determine the structure of the ZnO nanoparticles. Compared to the pure PLA film, the nano-blend film had a higher water vapor permeability (WVP) and lower oxygen permeability. With the increase of the nanoparticles (NPs) in the PLA, the elongation at break (ε) and elastic modulus (EM) increased, while tensile strength (TS) decreased. Thermogravimetric analysis (TGA) presented a relatively good thermostability. Most importantly, the physical and biochemical properties of the fresh-cut apple were also measured, such as weight loss, firmness, polyphenol oxidase (PPO), total phenolic content, browning index (BI), sensory quality, and microbiological level. The results indicated that nano-blend packaging films had the highest weight loss at the end of storage compared to the pure PLA film; however, nanopackaging provided a better retention of firmness, total phenolic countent, color, and sensory quality. It also had a remarkable inhibition on the growth of microorganisms. Therefore, Nano-ZnO active packaging could be used to improve the shelf-life of fresh-cut produce.

Method of synthesizing tungsten nanoparticles

Science.gov (United States)

Thoma, Steven G; Anderson, Travis M

2013-02-12

A method to synthesize tungsten nanoparticles has been developed that enables synthesis of nanometer-scale, monodisperse particles that can be stabilized only by tetrahydrofuran. The method can be used at room temperature, is scalable, and the product concentrated by standard means. Since no additives or stabilizing surfactants are required, this method is particularly well suited for producing tungsten nanoparticles for dispersion in polymers. If complete dispersion is achieved due to the size of the nanoparticles, then the optical properties of the polymer can be largely maintained.

ZnO synthesized in air by fs laser irradiation on metallic Zn thin films

Science.gov (United States)

Esqueda-Barrón, Y.; Herrera, M.; Camacho-López, S.

2018-05-01

We present results on rapid femtosecond laser synthesis of nanostructured ZnO. We used metallic Zn thin films to laser scan along straight tracks, until forming nanostructured ZnO. The synthesis dependence on laser irradiation parameters such as the per pulse fluence, integrated fluence, laser scan speed, and number of scans were explored carefully. SEM characterization showed that the morphology of the obtained ZnO is dictated by the integrated fluence and the laser scan speed; micro Raman and XRD results allowed to identify optimal laser processing conditions for getting good quality ZnO; and cathodoluminescence measurements demonstrated that a single laser scan at high per pulse laser fluence, but a medium integrated laser fluence and a medium laser scan speed favors a low density of point-defects in the lattice. Electrical measurements showed a correlation between resistivity of the laser produced ZnO and point-defects created during the synthesis. Transmittance measurements showed that, the synthesized ZnO can reach down to the supporting fused silica substrate under the right laser irradiation conditions. The physical mechanism for the formation of ZnO, under ultrashort pulse laser irradiation, is discussed in view of the distinct times scales given by the laser pulse duration and the laser pulse repetition rate.

Degradation of 4-Chlorophenol Under Sunlight Using ZnO Nanoparticles as Catalysts

Science.gov (United States)

Rajar, Kausar; Sirajuddin; Balouch, Aamna; Bhanger, M. I.; Sherazi, Tufail H.; Kumar, Raj

2018-03-01

Herein we demonstrate a simplistic microwave assisted chemical precipitation approach regarding the synthesis of zinc oxide nanoparticles. As-prepared ZnO nanoparticles (NPs) were characterized by UV-visible spectroscopy, Fourier transform infra-red spectroscopy, atomic force microscopy and x-ray diffractometry and scrutinized as photo-catalysts for degradation of 4-chlorophenol (4-CP) under sunlight. The study substantiated that 98.5% of 4-CP was degraded within 20 min in the absence of initiator like H2O2 which reflects an outstanding prospective use for ZnO NPs as photo-catalysts. The nanocatalysts were recycled four times and still showed catalytic efficiency up to 95.5% for degradation of 4-CP in the specified 20 min.

Light-induced antifungal activity of TiO2 nanoparticles/ZnO nanowires

International Nuclear Information System (INIS)

Haghighi, N.; Abdi, Y.; Haghighi, F.

2011-01-01

Antifungal activity of TiO 2 /ZnO nanostructures under visible light irradiation was investigated. A simple chemical method was used to synthesize ZnO nanowires. Zinc acetate dihydrate, Polyvinyl Pyrrolidone and deionized water were used as precursor, capping and solvent, respectively. TiO 2 nanoparticles were deposited on ZnO nanowires using an atmospheric pressure chemical vapor deposition system. X-ray diffraction pattern of TiO 2 /ZnO nano-composite has represented the diffraction peaks relating to the crystal planes of the TiO 2 (anatase and rutile) and ZnO. TiO 2 /ZnO nanostructure antifungal effect on Candida albicans biofilms was studied and compared with the activity of TiO 2 nanoparticles and ZnO nanowires. The high efficiency photocatalytic activity of TiO 2 nanoparticles leads to increased antifungal activity of ZnO nanowires. Scanning electron microscope was utilized to study the morphology of the as prepared nanostructures and the degradation of the yeast.

Synthesis of ZnO decorated graphene nanocomposite for enhanced photocatalytic properties

Science.gov (United States)

Gayathri, S.; Jayabal, P.; Kottaisamy, M.; Ramakrishnan, V.

2014-05-01

Zinc oxide/Graphene (GZ) composites with different concentrations of ZnO were successfully synthesized through simple chemical precipitation method. The X-ray diffraction pattern and the micro-Raman spectroscopic technique revealed the formation of GZ composite, and the energy dispersive X-ray spectrometry analysis showed the purity of the prepared samples. The ZnO nanoparticles decorated graphene sheets were clearly visible in the field emission scanning electron micrograph. Raman mapping was employed to analyze the homogeneity of the prepared samples. The diffuse-reflectance spectra clearly indicated that the formation of GZ composites promoted the absorption in the visible region also. The photocatalytic activity of ZnO and GZ composites was studied by the photodegradation of Methylene blue dye. The results revealed that the GZ composites exhibited a higher photocatalytic activity than pristine ZnO. Hence, we proposed a simple wet chemical method to synthesize GZ composite and its application on photocatalysis was demonstrated.

A dual-colored bio-marker made of doped ZnO nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Wu, Y L; Zeng, X T [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore); Fu, S; Kwek, L C [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, 637616 (Singapore); Tok, A I Y; Boey, F C Y [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Lim, C S [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

2008-08-27

Bio-compatible ZnO nanocrystals doped with Co, Cu and Ni cations, surface capped with two types of aminosilanes and titania are synthesized by a soft chemical process. Due to the small particle size (2-5 nm), surface functional groups and the high photoluminescence emissions at the UV and blue-violet wavelength ranges, bio-imaging on human osteosarcoma (Mg-63) cells and histiocytic lymphoma U-937 monocyte cells showed blue emission at the nucleus and bright turquoise emission at the cytoplasm simultaneously. This is the first report on dual-color bio-images labeled by one semiconductor nanocrystal colloidal solution. Bright green emission was detected on mung bean seedlings labeled by all the synthesized ZnO nanocrystals. Cytotoxicity tests showed that the aminosilanes capped nanoparticles are non-toxic. Quantum yields of the nanocrystals varied from 79% to 95%. The results showed the potential of the pure ZnO and Co-doped ZnO nanocrystals for live imaging of both human cells and plant systems.

Antiproliferative effects of ZnO, ZnO-MTCP, and ZnO-CuMTCP nanoparticles with safe intensity UV and X-ray irradiation.

Science.gov (United States)

Sadjadpour, Susan; Safarian, Shahrokh; Zargar, Seyed Jalal; Sheibani, Nader

2016-01-01

In photodynamic therapy (PDT) of cancer both the light and the photosensitizing agent are normally harmless, but in combination they could result in selective tumor killing. Zinc oxide nanoparticles were synthesized and coated with the amino acid cysteine to provide an adequate arm for conjugation with porphyrin photosensitizers (meso-tetra (4-carboxyphenyl) porphyrin [MTCP] and CuMTCP). Porphyrin-conjugated nanoparticles were characterized by TEM, FTIR, and UV-vis, and fluorescence spectrophotometry. The 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability in the presence or absence of porphyrin conjugates following UV and X-ray irradiation. The uptake of the porphyrin-conjugated ZnO nanoparticles by cells was detected using fluorescence microscopy. Our results indicated that the survival of T-47D cells was significantly compromised in the presence of ZnO-MTCP-conjugated nanostructures with UV light exposure. Exhibition of cytotoxic activity of ZnO-MTCP for human prostate cancer (Du145) cells occurred at a higher concentration, indicating the more resistant nature of these tumor cells. ZnO-CuMTCP showed milder cytotoxic effects in human breast cancer (T-47D) and no cytotoxic effects in Du145 with UV light exposure, consistent with its lower cytotoxic potency as well as cellular uptake. Surprisingly, none of the ZnO-porphyrin conjugates exhibited cytotoxic effects with X-ray irradiation, whereas ZnO alone exerted cytotoxicity. Thus, ZnO and ZnO-porphyrin nanoparticles with UV or X-ray irradiation may provide a suitable treatment option for various cancers. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Structural and Morphological Properties of Nanostructured ZnO Particles Grown by Ultrasonic Spray Pyrolysis Method with Horizontal Furnace

Directory of Open Access Journals (Sweden)

G. Flores-Carrasco

2014-01-01

Full Text Available ZnO nanoparticles were synthesized in a horizontal furnace at 500°C using different zinc nitrate hexahydrate concentrations (0.01 and 0.1 M as reactive solution by ultrasonic spray pyrolysis method. The physical-chemical properties of synthesized ZnO nanoparticles have been characterized by thermogravimetric analysis (TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, and high resolution transmission electron microscopy (HRTEM. With the TGA is has optimized the temperature at which the initial reactive (Zn(NO32·6H2O, is decomposed completely to give way to its corresponding oxide, ZnO. SEM revealed secondary particles with a quasispherical shape that do not change significantly with the increasing of precursor solution concentration as well as some content of the broken spheres. Increasing the precursor solution concentration leads to the increase in the average size of ZnO secondary particles from 248±73 to 470±160 nm; XRD reveals the similar tendency for the crystallite size which changes from 23±4 to 45±4 nm. HRTEM implies that the secondary particles are with hierarchical structure composed of primary nanosized subunits. These results showed that the precursor concentration plays an important role in the evolution on the size, stoichiometry, and morphology of ZnO nanoparticles.

Microwave Synthesized ZnO Nanorod Arrays for UV Sensors: A Seed Layer Annealing Temperature Study.

Science.gov (United States)

Pimentel, Ana; Ferreira, Sofia Henriques; Nunes, Daniela; Calmeiro, Tomas; Martins, Rodrigo; Fortunato, Elvira

2016-04-20

The present work reports the influence of zinc oxide (ZnO) seed layer annealing temperature on structural, optical and electrical properties of ZnO nanorod arrays, synthesized by hydrothermal method assisted by microwave radiation, to be used as UV sensors. The ZnO seed layer was produced using the spin-coating method and several annealing temperatures, ranging from 100 to 500 °C, have been tested. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and spectrophotometry measurements have been used to investigate the structure, morphology, and optical properties variations of the produced ZnO nanorod arrays regarding the seed layer annealing temperatures employed. After the growth of ZnO nanorod arrays, the whole structure was tested as UV sensors, showing an increase in the sensitivity with the increase of seed layer annealing temperature. The UV sensor response of ZnO nanorod arrays produced with the seed layer annealed temperature of 500 °C was 50 times superior to the ones produced with a seed layer annealed at 100 °C.

Effects of ZnO nanoparticles and microwave heating on the sterilization and product quality of vacuum-packaged Caixin.

Science.gov (United States)

Liu, Qian; Zhang, Min; Fang, Zhong-xiang; Rong, Xiao-hong

2014-09-01

The sterilization of vacuum-packaged Caixin (Brassica chinensis L.), which is a green-leafy vegetable and also a low-acid food, remains a difficult problem. In this study, effects of ZnO nanoparticles and microwave heating on the sterilization and product quality of vacuum-packaged Caixin were investigated. Addition of ZnO nanoparticle suspension at 0.01-0.02 g kg(-1) reduced the number of bacterial colonies. The antibacterial activity was enhanced with the increased amount of ZnO nanoparticles. Microwave heating (915 and 2450 MHz) was used to sterilize Caixin samples. Samples had good product quality (better greenness, chroma and hue angle values, lower browning index and acceptable texture) and the lowest total colony number under the microwave heating condition of 400 W 150 s (2450 MHz). The best sterilization condition was observed under 2450 MHz microwave (400 W 150 s) heating combined with 0.02 g kg(-1) ZnO nanoparticle addition, which led to a total colony number of <1 log CFU g(-1) in Caixin samples within 7 days. © 2014 Society of Chemical Industry.

Effect of ZnO nanoparticles to mechanical properties of thixoformed Mg-Al-Zn alloy

Science.gov (United States)

Kusharjanto; Soepriyanto, Syoni; Ardian Korda, Akhmad; Adi Dwiwanto, Supono

2018-03-01

Magnesium alloys are lightweight metallic materials with low mechanical properties. Therefore, in order to meet the requirements in various industrial sector applications such as automotive, aerospace and electronic frame, improvement strength and ductility is required. The purpose of this research is to investigate the effect of adding ZnO nanoparticles to changes in microstructure, hardness, mechanical properties regarding with yield and ultimate strength. In this research, the molten Mg-Al-Zn alloy is added ZnO nanoparticles with a various range of 0, 1; 3 and 5 wt% and then cooling in the room temperature. Futhermore, Mg-Al-Zn-ZnO is heated at a temperature of 530 °C (in the semi-solid temperature range 470 °C–595 °C or 53% solid fraction) and then thixoforming process is performed. The characterization results of the thixoforming product show that, the microstructure is globular in shape with maximum hardness value of 107.14 VHN, the yield strength of 214.87 MPa, and the ultimate tensile strength of 311.25 MPa in 5 wt% ZnO nanoparticles.

Use of Agave tequilana-lignin and zinc oxide nanoparticles for skin photoprotection.

Science.gov (United States)

Gutiérrez-Hernández, José Manuel; Escalante, Alfredo; Murillo-Vázquez, Raquel Nalleli; Delgado, Ezequiel; González, Francisco Javier; Toríz, Guillermo

2016-10-01

The use of sunscreens is essential for preventing skin damage and the potential appearance of skin cancer in humans. Inorganic active components such as zinc oxide (ZnO) have been used commonly in sunscreens due to their ability to block UVA radiation. This ultraviolet (UV) protection might be enhanced to cover the UVB and UVC bands when combined with other components such as titanium dioxide (TiO2). In this work we evaluate the photoprotection properties of organic nanoparticles made from lignin in combination with ZnO nanoparticles as active ingredients for sunscreens. Lignin nanoparticles were synthesized from Agave tequilana lignin. Two different pulping methods were used for dissolving lignin from agave bagasse. ZnO nanoparticles were synthesized by the precipitation method. All nanoparticles were characterized by SEM, UV-Vis and FT-IR spectroscopy. Nanoparticles were mixed with a neutral vehicle in different concentrations and in-vitro sun protection factor (SPF) values were calculated. Different sizes of spherical lignin nanoparticles were obtained from the spent liquors of two different pulping methods. ZnO nanoparticles resulted with a flake shape. The mixture of all components gave SPF values in a range between 4 and 13. Lignin nanoparticles showed absorption in the UVB and UVC regions which can enhance the SPF value of sunscreens composed only of zinc oxide nanoparticles. Lignin nanoparticles have the added advantage of being of organic nature and its brown color can be used to match the skin tone of the person using it. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhancing the numerical aperture of lenses using ZnO nanostructure-based turbid media

International Nuclear Information System (INIS)

Khokhra, Richa; Barman, Partha Bir; Kumar, Rajesh; Kumar, Manoj; Rawat, Nitin; Jang, Hwanchol; Lee, Heung-No

2013-01-01

Nanosheets, nanoparticles, and microstructures of ZnO were synthesized via a wet chemical method. ZnO films with a thickness of 44–46 μm were fabricated by spray coating, and these have been investigated for their potential use in turbid lens applications. A morphology-dependent comparative study of the transmittance of ZnO turbid films was conducted. Furthermore, these ZnO turbid films were used to enhance the numerical aperture (NA) of a Nikon objective lens. The variation in NA with different morphologies was explained using size-dependent scattering by the fabricated films. A maximum NA of around 1.971 of the objective lens with a turbid film of ZnO nanosheets was achieved. (paper)

Effect of ZnO nanoparticles in the oxygen uptake during aerobic wastewater treatment

Energy Technology Data Exchange (ETDEWEB)

Cervantes-Avilés, Pabel; Brito, Elcia M. S. [University of Guanajuato, Engineering Division, Department of Civil Engineering & Environmental Engineering (Mexico); Duran, Robert [Université de Pau et des Pays de l’Adour, Equipe Environment et Microbiologie (France); Martínez, Arodí Bernal; Cuevas-Rodríguez, Germán, E-mail: german28@ugto.mx [University of Guanajuato, Engineering Division, Department of Civil Engineering & Environmental Engineering (Mexico)

2016-07-15

The increased use of ZnO nanoparticles (NPs) in everyday products indicates the importance of studying NPs release to the wastewater and its possible effect on biological process for wastewater treatment. Therefore, the aim of this work was to study the effect of the presence of ZnO NPs in aerobic wastewater treatment. The results indicated that the oxygen uptake rate of microorganisms is inhibited for concentrations higher than 473 mg L{sup −1} of ZnO NPs. The diversity of microorganisms involved in wastewater treatment was reduced in presence of ZnO NPs. Related to morphological interaction between ZnO NPs and suspended biomass, physical damage in flocs structure were observed in presence of ZnO NPs. However, the internalization of Zn compounds in microorganisms not presented mechanical damage in the membrane cell. These findings suggest that inhibition in oxygen uptake was caused for negative effect that ZnO NPs induces in aerobic microorganisms involved in wastewater treatment.

Diameter optimization of VLS-synthesized ZnO nanowires, using statistical design of experiment

International Nuclear Information System (INIS)

Shafiei, Sepideh; Nourbakhsh, Amirhasan; Ganjipour, Bahram; Zahedifar, Mostafa; Vakili-Nezhaad, Gholamreza

2007-01-01

The possibility of diameter optimization of ZnO nanowires by using statistical design of experiment (DoE) is investigated. In this study, nanowires were synthesized using a vapor-liquid-solid (VLS) growth method in a horizontal reactor. The effects of six synthesis parameters (synthesis time, synthesis temperature, thickness of gold layer, distance between ZnO holder and substrate, mass of ZnO and Ar flow rate) on the average diameter of a ZnO nanowire were examined using the fractional factorial design (FFD) coupled with response surface methodology (RSM). Using a 2 III 6-3 FFD, the main effects of the thickness of the gold layer, synthesis temperature and synthesis time were concluded to be the key factors influencing the diameter. Then Box-Behnken design (BBD) was exploited to create a response surface from the main factors. The total number of required runs for the DoE process is 25, 8 runs for FFD parameter screening and 17 runs for the response surface obtained by BBD. Three extra runs are done to confirm the predicted results

Light-induced antifungal activity of TiO{sub 2} nanoparticles/ZnO nanowires

Energy Technology Data Exchange (ETDEWEB)

Haghighi, N. [Nano-Physics Research Lab., Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Abdi, Y., E-mail: y.abdi@ut.ac.ir [Nano-Physics Research Lab., Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Haghighi, F. [Department of Medical Mycology, School of Medical sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

2011-09-15

Antifungal activity of TiO{sub 2}/ZnO nanostructures under visible light irradiation was investigated. A simple chemical method was used to synthesize ZnO nanowires. Zinc acetate dihydrate, Polyvinyl Pyrrolidone and deionized water were used as precursor, capping and solvent, respectively. TiO{sub 2} nanoparticles were deposited on ZnO nanowires using an atmospheric pressure chemical vapor deposition system. X-ray diffraction pattern of TiO{sub 2}/ZnO nano-composite has represented the diffraction peaks relating to the crystal planes of the TiO{sub 2} (anatase and rutile) and ZnO. TiO{sub 2}/ZnO nanostructure antifungal effect on Candida albicans biofilms was studied and compared with the activity of TiO{sub 2} nanoparticles and ZnO nanowires. The high efficiency photocatalytic activity of TiO{sub 2} nanoparticles leads to increased antifungal activity of ZnO nanowires. Scanning electron microscope was utilized to study the morphology of the as prepared nanostructures and the degradation of the yeast.

Synthesis and characterization of rod-like ZnO decorated with γ-Fe{sub 2}O{sub 3} nanoparticles monolayer

Energy Technology Data Exchange (ETDEWEB)

Balti, Imen, E-mail: imenbalti12@yahoo.fr [Unité de Recherche 99/UR12-30, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna (Tunisia); Laboratoire des Sciences des Procédés et Matériaux, LSPM, CNRS, UPR 3407, Université Paris XIII, 99 Avenue J.B. Clément, 93430 Villetaneuse (France); Smiri, Laila Samia [Unité de Recherche 99/UR12-30, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna (Tunisia); Rabu, Pierre [Département de Chimie des Matériaux Inorganiques, IPCMS, UMR 7504, CNRS–UDS, 23, rue du Loess, BP 43, Strasbourg Cedex 2 (France); Gautron, Eric [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Viana, Bruno [LCMCP, Chimie-Paristech, UPMC, Collège de France, UMR CNRS 7574, 11 rue Pierre et Marie Curie, 75005 Paris (France); Jouini, Noureddine [Laboratoire des Sciences des Procédés et Matériaux, LSPM, CNRS, UPR 3407, Université Paris XIII, 99 Avenue J.B. Clément, 93430 Villetaneuse (France)

2014-02-15

Highlights: ► Rod-like ZnO decorated with γ-Fe{sub 2}O{sub 3} nanoparticles have been prepared using forced hydrolysis in polyol medium. ► The system presents excellent UV photoluminescence properties along with superparamagnetic behavior. -- Abstract: Decorated rod-like ZnO particles with γ-Fe{sub 2}O{sub 3} nanoparticles monolayer (ZnO@γ-Fe{sub 2}O{sub 3}) were prepared via a simple route using forced hydrolysis of metal acetates in a polyol medium. The phases and purity of the as-prepared particles were established by powder X-ray diffraction (PXRD) and X-ray photo-electron spectroscopy (XPS) analyses. Transmission electron microscopy (TEM) showed that the ZnO particles present a typical rod-like morphology with ∼80 nm diameter and ∼200–400 nm length. These nanorods are decorated with well-organized γ-Fe{sub 2}O{sub 3} spherical nanoparticles showing a narrow size distribution around 5 nm. The photoluminescence (PL) spectra of the bare ZnO particles show predominant UV-excitonic and weak visible emission. The latter vanishes after covering the surface with the γ-Fe{sub 2}O{sub 3} nanoparticles suggesting an effect on the oxygen stoichiometry at the surface of the ZnO nanorods. The decorated nanoparticles exhibit magnetic response to an external magnetic field at room temperature and a superparamagnetic character with very low blocking temperature likely related to the organisation of γ-Fe{sub 2}O{sub 3} nanoparticles as monolayer.

The effects of ZnO2 nanoparticles on properties of concrete using ground granulated blast furnace Slag as binder

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Ali Nazari

2011-09-01

Full Text Available In the present study, flexural strength together with pore structure, thermal behavior and microstructure of concrete containing ground granulated blast furnace slag with different amount of ZnO2 nanoparticles has been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impact the properties of concrete, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt. (%. ZnO2 nanoparticles with the average particle size of 15 nm were added partially to concrete with the optimum content of 45 wt. (% of ground granulated blast furnace slag and physical and mechanical properties of the specimens was measured. ZnO2 nanoparticle as a partial replacement of cement up to 3 wt. (% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH2 amount at the early age of hydration and hence increase flexural strength of concrete. The increased the ZnO2 nanoparticles' content more than 3 wt. (%, causes the reduced the flexural strength because of the decreased crystalline Ca(OH2 content required for C-S-H gel formation together with unsuitable dispersion of nanoparticles in the concrete matrix. ZnO2 nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.

Comparison on Bactericidal and Cytotoxic Effect of Silver Nanoparticles Synthesized by Different Methods

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Mala, R.; Celsia, A. S. Ruby; Malathi Devi, S.; Geerthika, S.

2017-08-01

Biologically synthesized silver nanoparticle are biocompatible for medical applications. The present work is aimed to synthesize silver nanoparticle using the fruit pulp of Tamarindusindica and to evaluate its antibacterial and anticancer activity against lung cancercell lines. Antibacterial activity was assessed by well diffusion method. Cytotoxicity was evaluated using MTT assay. GC-MS of fruit pulp extract showed the presence of levoglucosenone, n-hexadecanoic acid, 9,12-octadecadienoic acid etc. Antioxidant activity of the fruit pulp was determined by DPPH assay, hydrogen peroxide scavenging assay and lipid peroxidation. The size of biologically synthesized silver nanoparticle varied from 50 nm to 76 nm. It was 59 nm to 98 nm for chemically synthesized silver nanoparticle. Biologically synthesized silver nanoparticle showed 26 mm inhibition zone against E. coli and chemically synthesized silver nanoparticle showed 20 mm. Antioxidant activity of fruit extract by DPPH showed 84 % reduction. The IC 50 of biologically synthesized silver nanoparticle against lung cancer cell lines was 48 µg/ml. It was 95 µg/ml for chemically synthesized silver nanoparticle. The increased activity of biologically synthesized silver nanoparticle was due to its smaller size, stability and the bioactive compounds capping the silver nanoparticle extracted from the fruit extract.

Electron paramagnetic resonance in Cu-doped ZnO

Science.gov (United States)

Buchheit, R.; Acosta-Humánez, F.; Almanza, O.

2016-04-01

In this work, ZnO and Cu-doped ZnO nanoparticles (Zn1-xCuxO, x = 3%), with a calcination temperature of 500∘C were synthesized using the sol-gel method. The particles were analyzed using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) at X-band, measurement in a temperature range from 90 K to room temperature. AAS confirmed a good correspondence between the experimental doping concentration and the theoretical value. XRD reveals the presence of ZnO phase in hexagonal wurtzite structure and a nanoparticle size for the samples synthesized. EPR spectroscopy shows the presence of point defects in both samples with g-values of g = 1.959 for shallow donors and g = 2.004 for ionized vacancies. It is important when these materials are required have been used as catalysts, as suggested that it is not necessary prepare them at higher temperature. A simulation of the Cu EPR signal using an anisotropic spin Hamiltonian was performed and showed good coincidence with the experimental spectra. It was shown that Cu2+ ions enter interstitial octahedral sites of orthorhombic symmetry in the wurtzite crystal structure. Temperature dependence of the EPR linewidth and signal intensity shows a paramagnetic behavior of the sample in the measurement range. A Néel temperature TN = 78 ± 19 K was determined.

Eosin Yellowish Dye-Sensitized ZnO Nanostructure-Based Solar Cells Employing Solid PEO Redox Couple Electrolyte

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S. S. Kanmani

2012-01-01

Full Text Available ZnO nanostructures are synthesized by low-temperature methods, and they possess polycrystalline hexagonal wurtzite structure with preferential c-axial growth. Morphological study by SEM shows the presence of ~30 nm sized spherical-shaped ZnO nanoparticle, the branched flower-like ZnO composed of many nanorods (length: 1.2 to 4.2 μm and diameter: 0.3 to 0.4 μm, and ~50 nm diameter of individual ZnO nanorods. Reduction in photoemission intensity of nanorods infers the decrease in electron-hole recombination rate, which offers better photovoltaic performance. The dye-sensitized solar cell (DSSC based on ZnO nanorods sensitized with Eosin yellowish dye exhibits a maximum optimal energy conversion efficiency of 0.163% compared to that of nanoparticles and nanoflowers, due to better dye loading and direct conduction pathway for electron transport.

xanthen-11-ones by ZnO Nanoparticles Catalyzed Three Co

African Journals Online (AJOL)

NICO

Highly effective zinc oxide nanoparticles catalyzed solvent-free synthesis of some tetrahydrobenzo[a]xanthen-11-one derivatives ... efficient, green and simple method for the preparation of ... Characterization of ZnO NPs structure was continued by SEM ... catalysts may be related to higher surface area available for.

Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

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Sini Kuriakose

2013-11-01

Full Text Available Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures showed enhanced photocatalytic activity towards sun-light driven photodegradation of methylene blue dye (MB as compared to ZnO nanoparticles. XRD, UV–vis absorption, PL, FTIR and TEM studies revealed the formation of Zn(OH2 surface layer on ZnO nanostructures upon ageing. We demonstrate that the formation of a passivating Zn(OH2 surface layer on the ZnO nanostructures upon ageing deteriorates their efficiency to photocatalytically degrade of MB.

A review on biogenic synthesis of ZnO nanoparticles using plant extracts and microbes: A prospect towards green chemistry.

Science.gov (United States)

Ahmed, Shakeel; Annu; Chaudhry, Saif Ali; Ikram, Saiqa

2017-01-01

Nanotechnology is emerging as an important area of research with its tremendous applications in all fields of science, engineering, medicine, pharmacy, etc. It involves the materials and their applications having one dimension in the range of 1-100nm. Generally, various techniques are used for syntheses of nanoparticles (NPs) viz. laser ablation, chemical reduction, milling, sputtering, etc. These conventional techniques e.g. chemical reduction method, in which various hazardous chemicals are used for the synthesis of NPs later become liable for innumerable health risks due to their toxicity and endangering serious concerns for environment, while other approaches are expensive, need high energy for the synthesis of NPs. However, biogenic synthesis method to produce NPs is eco-friendly and free of chemical contaminants for biological applications where purity is of concerns. In biological method, different biological entities such as extract, enzymes or proteins of a natural product are used to reduce and stabilised formation of NPs. The nature of these biological entities also influence the structure, shape, size and morphology of synthesized NPs. In this review, biogenic synthesis of zinc oxide (ZnO) NPs, procedures of syntheses, mechanism of formation and their various applications have been discussed. Various entities such as proteins, enzymes, phytochemicals, etc. available in the natural reductants are responsible for synthesis of ZnO NPs. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of ZnO decoration on the photovoltaic performance of TiO{sub 2} based dye sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Yang, Long; Zhai, Bao-gai [School of Mathematics and Physics, Changzhou University, Jiangsu 213164 (China); Ma, Qing-lan [School of Electronics and Information, Nantong University, Jiangsu 226019 (China); Huang, Yuan Ming, E-mail: dongshanisland@126.com [School of Electronics and Information, Nantong University, Jiangsu 226019 (China)

2014-08-25

Highlights: • Various ZnO morphologies coated TiO{sub 2} photoanodes are formed and applied to DSSCs. • The effect of photoanode morphology on performance of DSSCs was studied. • ZnO NRs@TiO{sub 2} electrode provides more dye absorption and fast transfer pathway. • The η of DSSC with ZnO NRs@TiO{sub 2} is increased over fourfold than other DSSCs. - Abstract: ZnO nanoparticles and one-dimensional vertically aligned ZnO nanorods were grown on the TiO{sub 2} layers in the photoanodes via the hydrothermal method at 60 and 90 °C, respectively. The effect of ZnO decoration on the photovoltaic performance of TiO{sub 2} based dye sensitized solar cells (DSSCs) was investigated. The morphologies, crystalline structures and optical properties of the synthesized ZnO nanoparticles and ZnO nanorods were characterized by field-emission scanning electron microscope, X-ray diffractometer and photoluminescence spectroscopy, respectively. The photocurrent–voltage curves of the fabricated DSSCs showed that the ZnO nanorods decorated DSSCs exhibited better photovoltaic performance than the ZnO nanoparticles decorated DSSCs. The improved performance of the ZnO nanorods decorated DSSCs can be ascribed to the fact that the vertically aligned ZnO nanorods provide high specific surface area for dye adsorption and the efficient pathway for electron transportation.