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Sample records for aligned zinc oxide

  1. Biomimetic alignment of zinc oxide nanoparticles along a peptide nanofiber.

    PubMed

    Tomizaki, Kin-ya; Kubo, Seiya; Ahn, Soo-Ang; Satake, Masahiko; Imai, Takahito

    2012-09-18

    Zinc oxide (ZnO) has potential applications in solar cells, chemical sensors, and piezoelectronic and optoelectronic devices due to its attractive physical and chemical properties. Recently, a solution-phase method has been used to synthesize ZnO crystals with diverse (from simple to hierarchical) nanostructures that is simple, of low cost, and scalable. This method requires template molecules to control the morphology of the ZnO crystals. In this paper, we describe the design and synthesis of two short peptides (RU-003,Ac-AIEKAXEIA-NH(2); RU-027, EAHVMHKVAPRPGGGAIEKAXEIA-NH(2); X = l-2-naphthylalanine) and the characterization of their self-assembled nanostructures. We also report their potential for ZnO mineralization and the alignment of ZnO nanoparticles along peptide nanostructures at room temperature. Interestingly, nonapeptide RU-003 predominantly formed a straight fibrous structure and induced the nucleation of ZnO at its surface, leading to an alignment of ZnO nanoparticles along a peptide nanofiber. This novel method holds promise for the room-temperature fabrication of ZnO catalysts with increased specific surface area, ZnO-gated transistors, and ZnO-based nanomaterials for optical applications.

  2. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    PubMed

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications.

  3. Growth and properties of ultra-violet emitting aligned zinc oxide nanocones with hexagonal caps.

    PubMed

    Umar, Ahmad; Al Hajry, A; Al-Ghamdi, A A; Al-Heniti, S

    2010-10-01

    Ultraviolet-emitting, single-crystalline aligned zinc oxide (ZnO) nanocones with hexagonal caps were grown on silicon substrate via simple non-catalytic thermal evaporation process. High-purity metallic zinc powder and oxygen were used as source materials for zinc and oxygen, respectively. The detailed structural characterizations confirmed that the formed products are single-crystalline, possess a wurtzite hexagonal phase and grown along the c-axis direction. Raman-active optical-phonon E2(high) mode at 437 cm(-1) with sharp and strong UV emission at 385 nm in room-temperature photoluminescence (PL) spectrum demonstrated that the as-grown ZnO nanocones with hexagonal caps possess good-crystal quality with the excellent optical properties. Finally, a plausible growth mechanism for the formation of as-grown ZnO nanocones with hexagonal caps was also proposed.

  4. Self-aligned top-gate amorphous gallium indium zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Park, Jaechul; Song, Ihun; Kim, Sunil; Kim, Sangwook; Kim, Changjung; Lee, Jaecheol; Lee, Hyungik; Lee, Eunha; Yin, Huaxiang; Kim, Kyoung-Kok; Kwon, Kee-Won; Park, Youngsoo

    2008-08-01

    We have demonstrated a self-aligned top-gate amorphous gallium indium zinc oxide thin film transistor (a-GIZO TFT). It had a field effect mobility of 5 cm2/V s, a threshold voltage of 0.2 V, and a subthreshold swing of 0.2 V/decade. Ar plasma was treated on the source/drain region of the a-GIZO active layer to reduce the series resistance. After Ar plasma treatment, the surface of the source/drain region was divided into In-rich and In-deficient regions. The a-GIZO TFT also had a constant sheet resistance of 1 kΩ/◻ for a film thickness of over 40 nm. The interface between the source/drain Mo metal and the Ar plasma-treated a-GIZO indicated a good Ohmic contact and a contact resistivity of 50 μΩ cm2.

  5. Coating and enhanced photocurrent of vertically aligned zinc oxide nanowire arrays with metal sulfide materials.

    PubMed

    Volokh, Michael; Diab, Mahmud; Magen, Osnat; Jen-La Plante, Ilan; Flomin, Kobi; Rukenstein, Pazit; Tessler, Nir; Mokari, Taleb

    2014-08-27

    Hybrid nanostructures combining zinc oxide (ZnO) and a metal sulfide (MS) semiconductor are highly important for energy-related applications. Controlled filling and coating of vertically aligned ZnO nanowire arrays with different MS materials was achieved via the thermal decomposition approach of single-source precursors in the gas phase by using a simple atmospheric-pressure chemical vapor deposition system. Using different precursors allowed us to synthesize multicomponent structures such as nanowires coated with alloy shell or multishell structures. Herein, we present the synthesis and structural characterization of the different structures, as well as an electrochemical characterization and a photovoltaic response of the ZnO-CdS system, in which the resulting photocurrent upon illumination indicates charge separation at the interface.

  6. Template-Assisted Hydrothermal Growth of Aligned Zinc Oxide Nanowires for Piezoelectric Energy Harvesting Applications

    PubMed Central

    2016-01-01

    A flexible and robust piezoelectric nanogenerator (NG) based on a polymer-ceramic nanocomposite structure has been successfully fabricated via a cost-effective and scalable template-assisted hydrothermal synthesis method. Vertically aligned arrays of dense and uniform zinc oxide (ZnO) nanowires (NWs) with high aspect ratio (diameter ∼250 nm, length ∼12 μm) were grown within nanoporous polycarbonate (PC) templates. The energy conversion efficiency was found to be ∼4.2%, which is comparable to previously reported values for ZnO NWs. The resulting NG is found to have excellent fatigue performance, being relatively immune to detrimental environmental factors and mechanical failure, as the constituent ZnO NWs remain embedded and protected inside the polymer matrix. PMID:27172933

  7. Synthesis of Vertically-Aligned Zinc Oxide Nanowires and Their Application as a Photocatalyst

    PubMed Central

    Zhou, Qiong; Wen, John Z.; Zhao, Pei; Anderson, William A.

    2017-01-01

    Vertically aligned zinc oxide (ZnO) nanowires were hydrothermally synthesized on a glass substrate with the assistance of a pre-coated ZnO seeding layer. The crystalline structure, morphology and transmission spectrum of the as-synthesized sample were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and ultraviolet-visible (UV-Vis) spectrophotometry, respectively, indicating a wurzite ZnO material of approximately 100 nm wire diameter and absorbance at 425 nm and lower wavelengths. The photocatalytic activity of the sample was tested via the degradation of methyl orange in aqueous solution under UV-A irradiation. The synthesized nanowires showed a high photocatalytic activity, which increased up to 90% degradation in 2 h as pH was increased to 12. It was shown that the photocatalytic activity of the nanowires was proportional to the length to diameter ratio of the nanowires, which was in turn controlled by the growth time and grain size of the seed layer. Estimates suggest that diffusion into the regions between nanowires may be significantly hindered. Finally, the reusability of the prepared ZnO nanowire samples was also investigated, with results showing that the nanowires still showed 97% of its original photoactivity after ten cycles of use. PMID:28336843

  8. Electrical and gas sensing properties of self-aligned copper-doped zinc oxide nanoparticles

    SciTech Connect

    Sonawane, Yogesh S.; Kanade, K.G.; Kale, B.B. Aiyer, R.C.

    2008-10-02

    Electrical and gas sensing properties of nanocrystalline ZnO:Cu, having Cu X wt% (X = 0.0, 0.5, 1.0, and 1.5) in ZnO, in the form of pellet were investigated. Copper chloride and zinc acetate were used as precursors along with oxalic acid as a precipitating reagent in methanol. Material characterization was done by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and inductive coupled plasma with optical emission spectrometry (ICP-OES). FE-SEM showed the self-aligned Cu-doped ZnO nano-clusters with particles in the range of 40-45 nm. The doping of 0.5% of copper changes the electrical conductivity by an order of magnitude whereas the temperature coefficient of resistance (TCR) reduces with increase in copper wt% in ZnO. The material has shown an excellent sensitivity for the H{sub 2}, LPG and CO gases with limited temperature selectivity through the optimized operating temperature of 130, 190 and 220 deg. C for H{sub 2}, LPG and CO gases, respectively at 625 ppm gas concentration. The %SF was observed to be 1460 for H{sub 2} at 1% Cu doping whereas the 0.5% Cu doping offered %SF of 950 and 520 for CO and LPG, respectively. The response and recovery time was found to be 6 to 8 s and 16 s, respectively.

  9. Amperometric Non-Enzymatic Hydrogen Peroxide Sensor Based on Aligned Zinc Oxide Nanorods

    PubMed Central

    Al-Hardan, Naif H.; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Othman, Norinsan Kamil; Kar Keng, Lim

    2016-01-01

    Zinc oxide (ZnO) nanorods (NRs) have been synthesized via the hydrothermal process. The NRs were grown over a conductive glass substrate. A non-enzymatic electrochemical sensor for hydrogen peroxide (H2O2), based on the prepared ZnO NRs, was examined through the use of current-voltage measurements. The measured currents, as a function of H2O2 concentrations ranging from 10 μM to 700 μM, revealed two distinct behaviours and good performance, with a lower detection limit (LOD) of 42 μM for the low range of H2O2 concentrations (first region), and a LOD of 143.5 μM for the higher range of H2O2 concentrations (second region). The prepared ZnO NRs show excellent electrocatalytic activity. This enables a measurable and stable output current. The results were correlated with the oxidation process of the H2O2 and revealed a good performance for the ZnO NR non-enzymatic H2O2 sensor. PMID:27367693

  10. Enhanced field emission properties from well-aligned zinc oxide nanoneedles grown on the Au/Ti/n-Si substrate

    SciTech Connect

    Park, Chan Jun; Choi, Duck-Kyun; Yoo, Jinkyoung; Yi, Gyu-Chul; Lee, Cheol Jin

    2007-02-19

    The authors investigated the field emission from vertically well-aligned zinc oxide (ZnO) nanoneedles grown on the Au/Ti/n-Si (100) substrate using metal organic chemical vapor deposition. The turn-on field of ZnO nanoneedles was about 0.85 V/{mu}m at the current density of 0.1 {mu}A/cm{sup 2}, and the emission current density of 1 mA/cm{sup 2} was achieved at the applied electric field of 5.0 V/{mu}m. The low turn-on field of the ZnO nanoneedles was attributed to very sharp tip morphology, and the high emission current density was mainly caused by the formation of the stable Ohmic contact between the ZnO nanoneedles and Au film.

  11. Zinc oxide overdose

    MedlinePlus

    Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...

  12. Doped zinc oxide microspheres

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  13. Doped zinc oxide microspheres

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  14. Arsenic doped zinc oxide

    SciTech Connect

    Volbers, N.; Lautenschlaeger, S.; Leichtweiss, T.; Laufer, A.; Graubner, S.; Meyer, B. K.; Potzger, K.; Zhou Shengqiang

    2008-06-15

    As-doping of zinc oxide has been approached by ion implantation and chemical vapor deposition. The effect of thermal annealing on the implanted samples has been investigated by using secondary ion mass spectrometry and Rutherford backscattering/channeling geometry. The crystal damage, the distribution of the arsenic, the diffusion of impurities, and the formation of secondary phases is discussed. For the thin films grown by vapor deposition, the composition has been determined with regard to the growth parameters. The bonding state of arsenic was investigated for both series of samples using x-ray photoelectron spectroscopy.

  15. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  16. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  17. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  18. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  19. Zinc oxide varistors and/or resistors

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-07-27

    Varistors and/or resistors are described that include doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

  20. Zinc oxide varistors and/or resistors

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    Varistors and/or resistors that includes doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

  1. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of...

  2. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  3. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  4. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  5. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  6. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  7. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  8. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  9. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  10. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  11. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  12. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... amounts consistent with good manufacturing practice. (d) Labeling. The color additive and any mixtues... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc...). It is principally composed of Zn. (2) Color additive mixtures for drug use made with zinc oxide...

  13. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    PubMed

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications.

  14. Process of in situ forming well-aligned zinc oxide nanorod arrays on wood substrate using a two-step bottom-up method.

    PubMed

    Liu, Yongzhuang; Fu, Yanchun; Yu, Haipeng; Liu, Yixing

    2013-10-01

    A good nanocrystal covering layer on wood can serve as a protective coating and present some new surface properties. In this study, well-aligned ZnO nanorods (NRs) arrays were successfully grown on wood surface through a two-step bottom-up growth process. The process involved pre-sow seeds and subsequently their growing into NRs under hydrothermal environment. The interface incorporation between wood and ZnO colloid particles in the precursor solution during the seeding process was analyzed and demonstrated through a schematic. The growth process of forming well-aligned ZnO NRs was analyzed by field-emission scanning electron microscopy and X-ray diffraction, which showed that the NRs elongated with increased reaction time. The effects of ZnO crystal form and capping agent on the growth process were studied through different viewpoints.

  15. Bidirectional reflectance of zinc oxide

    NASA Technical Reports Server (NTRS)

    Scott, R.

    1973-01-01

    This investigation was undertaken to determine original and useful information about the bidirection reflectance of zinc oxide. The bidirectional reflectance will be studied for the spectra between .25-2.5 microns and the hemisphere above the specimen. The following factors will be considered: (1) surface conditions; (2) specimen preparation; (3) specimen substrate, (4) polarization; (5) depolarization; (6) wavelength; and (7) angles of incident and reflection. The bidirectional reflectance will be checked by experimentally determined angular hemispherical measurements or hemispherical measurements will be used to obtain absolute bidirectional reflectance.

  16. Directed spatial organization of zinc oxide nanostructures

    DOEpatents

    Hsu, Julia; Liu, Jun

    2009-02-17

    A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

  17. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a)...

  18. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Zinc oxide. 182.8991 Section 182.8991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a)...

  19. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a)...

  20. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a)...

  1. Plasma-Sprayed Photocatalytic Zinc Oxide Coatings

    NASA Astrophysics Data System (ADS)

    Navidpour, A. H.; Kalantari, Y.; Salehi, M.; Salimijazi, H. R.; Amirnasr, M.; Rismanchian, M.; Azarpour Siahkali, M.

    2017-03-01

    Fabrication of semiconductor coatings with photocatalytic action for photodegradation of organic pollutants is highly desirable. In this research, pure zinc oxide, which is well known for its promising photocatalytic activity, was deposited on stainless-steel plates by plasma spraying. The phase composition and microstructure of the deposited films were studied by x-ray diffraction analysis and scanning electron microscopy, respectively. Despite the low-energy conditions of the plasma spraying process, the zinc oxide coatings showed good mechanical integrity on the substrate. Their photocatalytic activity was evaluated using aqueous solution of methylene blue at concentration of 5 mg L-1. The results showed the potential of the plasma spraying technique to deposit zinc oxide coatings with photocatalytic action under ultraviolet illumination. Ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy confirmed that the plasma spraying method could deposit zinc oxide films with higher photoabsorption ability relative to the initial powder.

  2. Patterned Fabrication of Zinc Oxide Nanowire Arrays

    NASA Astrophysics Data System (ADS)

    Khan, Sahar; Lamson, Thomas; Xu, Huizhong

    Zinc oxide nanowires possess desirable mechanical, thermodynamic, electrical, and optical properties. Although the hydrothermal growth process can be applied in tolerable growth conditions, the dimension and density of nanowires has a complex dependence on substrate pre-treatment, precursor concentrations, and growth conditions. Precise control of the geometry and density of nanowires as well as the location of nanowires would allow for the fabrication of useful nanowaveguide devices. In this work, we used electron beam lithography to pattern hole arrays in a polymer layer on gold-coated glass substrates and synthesized zinc oxide nanowires inside these holes. Arrays of nanowires with diameters ranging from 50 nm to 140 nm and various spacings were obtained. The transmission of light through these zinc oxide nanowire arrays in a silver film was also studied. This research was supported by the Seed Grant Program of St. John's University and the National Science Foundation under Grant No. CBET-0953645.

  3. Zinc oxide interdigitated electrode for biosensor application

    NASA Astrophysics Data System (ADS)

    Sin L., L.; Arshad, M. K. Md.; Fathil, M. F. M.; Adzhri, R.; M. Nuzaihan M., N.; Ruslinda, A. R.; Gopinath, Subash C. B.; Hashim, U.

    2016-07-01

    In biosensors, zinc oxide (ZnO) thin film plays a crucial role in term of stability, sensitivity, biocompatibility and low cost. Interdigitated electrode (IDE) design is one of the device architecture in biosensor for label free, stability and sensitivity. In this paper, we discuss the fabrication of zinc oxide deposited on the IDE as a transducer for sensing of biomolecule. The formation of APTES had increase the performance of the surface functionalization..Furthermore we extend the discuss on the surface functionalization process which is utilized for probe attachment onto the surface of biosensor through surface immobilization process, thus enables the sensing of biomolecules for biosensor application.

  4. Aluminum doped zinc oxide for organic photovoltaics

    SciTech Connect

    Murdoch, G. B.; Hinds, S.; Sargent, E. H.; Tsang, S. W.; Mordoukhovski, L.; Lu, Z. H.

    2009-05-25

    Aluminum doped zinc oxide (AZO) was grown via magnetron sputtering as a low-cost alternative to indium tin oxide (ITO) for organic photovoltaics (OPVs). Postdeposition ozone treatment resulted in devices with lower series resistance, increased open-circuit voltage, and power conversion efficiency double that of devices fabricated on untreated AZO. Furthermore, cells fabricated using ozone treated AZO and standard ITO displayed comparable performance.

  5. Correlation of Zinc with Oxidative Stress Biomarkers

    PubMed Central

    Morales-Suárez-Varela, María; Llopis-González, Agustín; González-Albert, Verónica; López-Izquierdo, Raúl; González-Manzano, Isabel; Cháves, Javier; Huerta-Biosca, Vicente; Martin-Escudero, Juan C.

    2015-01-01

    Hypertension and smoking are related with oxidative stress (OS), which in turn reports on cellular aging. Zinc is an essential element involved in an individual’s physiology. The aim of this study was to evaluate the relation of zinc levels in serum and urine with OS and cellular aging and its effect on the development of hypertension. In a Spanish sample with 1500 individuals, subjects aged 20–59 years were selected, whose zinc intake levels fell within the recommended limits. These individuals were classified according to their smoking habits and hypertensive condition. A positive correlation was found (Pearson’s C = 0.639; p = 0.01) between Zn serum/urine quotient and oxidized glutathione levels (GSSG). Finally, risk of hypertension significantly increased when the GSSG levels exceeded the 75 percentile; OR = 2.80 (95%CI = 1.09–7.18) and AOR = 3.06 (95%CI = 0.96–9.71). Low zinc levels in serum were related with OS and cellular aging and were, in turn, to be a risk factor for hypertension.  PMID:25774936

  6. Process for preparing zinc oxide-based sorbents

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2011-06-07

    The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  7. Novel synthetic methodology for controlling the orientation of zinc oxide nanowires grown on silicon oxide substrates

    NASA Astrophysics Data System (ADS)

    Cho, Jinhyun; Salleh, Najah; Blanco, Carlos; Yang, Sungwoo; Lee, Chul-Jin; Kim, Young-Woo; Kim, Jungsang; Liu, Jie

    2014-03-01

    This study presents a simple method to reproducibly obtain well-aligned vertical ZnO nanowire arrays on silicon oxide (SiOx) substrates using seed crystals made from a mixture of ammonium hydroxide (NH4OH) and zinc acetate (Zn(O2CCH3)2) solution. In comparison, high levels of OH- concentration obtained using NaOH or KOH solutions lead to incorporation of Na or K atoms into the seed crystals, destroying the c-axis alignment of the seeds and resulting in the growth of misaligned nanowires. The use of NH4OH eliminates the metallic impurities and ensures aligned nanowire growth in a wide range of OH- concentrations in the seed solution. The difference of crystalline orientations between NH4OH- and NaOH-based seeds is directly observed by lattice-resolved images and electron diffraction patterns using a transmission electron microscope (TEM). This study obviously suggests that metallic impurities incorporated into the ZnO nanocrystal seeds are one of the factors that generates the misaligned ZnO nanowires. This method also enables the use of silicon oxide substrates for the growth of vertically aligned nanowires, making ZnO nanostructures compatible with widely used silicon fabrication technology.This study presents a simple method to reproducibly obtain well-aligned vertical ZnO nanowire arrays on silicon oxide (SiOx) substrates using seed crystals made from a mixture of ammonium hydroxide (NH4OH) and zinc acetate (Zn(O2CCH3)2) solution. In comparison, high levels of OH- concentration obtained using NaOH or KOH solutions lead to incorporation of Na or K atoms into the seed crystals, destroying the c-axis alignment of the seeds and resulting in the growth of misaligned nanowires. The use of NH4OH eliminates the metallic impurities and ensures aligned nanowire growth in a wide range of OH- concentrations in the seed solution. The difference of crystalline orientations between NH4OH- and NaOH-based seeds is directly observed by lattice-resolved images and electron

  8. A LABORATORY COMPARISON OF FOUR ZINC OXIDE-EUGENOL FORMULATIONS AS RESTORATIVE MATERIALS.

    DTIC Science & Technology

    The ability of four zinc oxide - eugenol formulations to serve as long-term intermediate restorative materials was investigated. They were: (a...zinc oxide - eugenol , (b) zinc oxide - eugenol + EBA (ethoxybenzoic acid), (c) reinforced zinc oxide - eugenol , and (d) a reinforced zinc oxide - eugenol

  9. Zinc oxide nanowire networks for macroelectronic devices

    NASA Astrophysics Data System (ADS)

    Unalan, Husnu Emrah; Zhang, Yan; Hiralal, Pritesh; Dalal, Sharvari; Chu, Daping; Eda, Goki; Teo, K. B. K.; Chhowalla, Manish; Milne, William I.; Amaratunga, Gehan A. J.

    2009-04-01

    Highly transparent zinc oxide (ZnO) nanowire networks have been used as the active material in thin film transistors (TFTs) and complementary inverter devices. A systematic study on a range of networks of variable density and TFT channel length was performed. ZnO nanowire networks provide a less lithographically intense alternative to individual nanowire devices, are always semiconducting, and yield significantly higher mobilites than those achieved from currently used amorphous Si and organic TFTs. These results suggest that ZnO nanowire networks could be ideal for inexpensive large area electronics.

  10. Recent developments in zinc oxide target chemistry

    SciTech Connect

    Heaton, R.C.; Taylor, W.A.; Phillips, D.R.; Jamriska, D.J. Sr.; Garcia, J.B.

    1994-04-01

    Zinc oxide targets irradiated with high energy protons at the Los Alamos Meson Physics Facility (LAMPF) contain a number of radioactive spallation products in quantities large enough to warrant recovery. This paper describes methods for recovering {sup 7}Be, {sup 46}Sc, and {sup 48}V from such targets and offers suggestions on possible ways to recover additional isotopes. The proposed methods are based on traditional precipitation and ion exchange techniques, are readily adaptable to hot cell use, and produce no hazardous waste components. The products are obtained in moderate to high yields and have excellent radiopurity.

  11. Photocatalytic oxidation of methane over silver decorated zinc oxide nanocatalysts.

    PubMed

    Chen, Xuxing; Li, Yunpeng; Pan, Xiaoyang; Cortie, David; Huang, Xintang; Yi, Zhiguo

    2016-07-20

    The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the photo-activity via the surface plasmon resonance. The high quantum yield of 8% at wavelengths <400 nm and over 0.1% at wavelengths ∼470 nm achieved on the silver decorated zinc oxide nanostructures shows great promise for atmospheric methane oxidation. Moreover, the nano-particulate composites can efficiently photo-oxidize other small molecular hydrocarbons such as ethane, propane and ethylene, and in particular, can dehydrogenize methane to generate ethane, ethylene and so on. On the basis of the experimental results, a two-step photocatalytic reaction process is suggested to account for the methane photo-oxidation.

  12. Photocatalytic oxidation of methane over silver decorated zinc oxide nanocatalysts

    PubMed Central

    Chen, Xuxing; Li, Yunpeng; Pan, Xiaoyang; Cortie, David; Huang, Xintang; Yi, Zhiguo

    2016-01-01

    The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the photo-activity via the surface plasmon resonance. The high quantum yield of 8% at wavelengths <400 nm and over 0.1% at wavelengths ∼470 nm achieved on the silver decorated zinc oxide nanostructures shows great promise for atmospheric methane oxidation. Moreover, the nano-particulate composites can efficiently photo-oxidize other small molecular hydrocarbons such as ethane, propane and ethylene, and in particular, can dehydrogenize methane to generate ethane, ethylene and so on. On the basis of the experimental results, a two-step photocatalytic reaction process is suggested to account for the methane photo-oxidation. PMID:27435112

  13. Electrochemical synthesis of vertically aligned zinc nanowires using track-etched polycarbonate membranes as templates.

    PubMed

    Liu, Z; Zein El Abedin, S; Ghazvini, M S; Endres, F

    2013-07-21

    In the present paper, vertically aligned arrays of zinc nanowires were synthesized by electrochemical deposition into ion track-etched polycarbonate membranes in the ionic liquid electrolyte 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO)/Zn(TfO)2. Cyclic voltammetry and chronoamperometry were performed to investigate the electrochemical growth of zinc nanowires inside of the membranes. The transport processes and mechanisms of the nanowire growth in the membranes are also discussed. A supporting zinc or copper layer was deposited on the sputtered side in order to make the back layer thick enough to stabilize the wires. Zinc nanowires with a diameter of 90 nm and a length of up to 18 μm were obtained after removing the template. Furthermore, short nanowires with lengths less than 5 μm and a sandwich-like structure with nanowires in the middle were also synthesized. Vertically aligned zinc nanowire structures on such a substrate might be a potential anode candidate for future generation lithium ion batteries.

  14. Zinc.

    PubMed

    Barceloux, D G

    1999-01-01

    The use of zinc in metal alloys and medicinal lotions dates back before the time of Christ. Currently, most of the commercial production of zinc involves the galvanizing of iron and the manufacture of brass. Some studies support the use of zinc gluconate lozenges to treat the common cold, but there are insufficient data at this time to recommend the routine use of these lozenges. Zinc is an essential co-factor in a variety of cellular processes including DNA synthesis, behavioral responses, reproduction, bone formation, growth, and wound healing. Zinc is a relatively common metal with an average concentration of 50 mg/kg soil and a range of 10-300 mg/kg soil. Meat, seafood, dairy products, nuts, legumes, and whole grains contain relatively high concentrations of zinc. The mobility of zinc in anaerobic environments is poor and therefore severe zinc contamination occurs primarily near points sources of zinc release. The recommended daily allowance for adults is 15 mg zinc. The ingestion of 1-2 g zinc sulfate produces emesis. Zinc compounds can produce irritation and corrosion of the gastrointestinal tract, along with acute renal tubular necrosis and interstitial nephritis. Inhalation of high concentrations of zinc chloride from smoke bombs detonated in closed spaces may cause chemical pneumonitis and adult respiratory distress syndrome. In the occupational setting inhalation of fumes from zinc oxide is the most common cause of metal fume fever (fatigue, chills, fever, myalgias, cough, dyspnea, leukocytosis, thirst, metallic taste, salivation). Zinc compounds are not suspected carcinogens. Treatment of zinc toxicity is supportive. Calcium disodium ethylenediaminetetraacetate (CaNa2EDTA) is the chelator of choice based on case reports that demonstrate normalization of zinc concentrations, but there are few clinical data to confirm the efficacy of this agent.

  15. Relative Penetration of Zinc Oxide and Zinc Ions into Human Skin after Application of Different Zinc Oxide Formulations.

    PubMed

    Holmes, Amy M; Song, Zhen; Moghimi, Hamid R; Roberts, Michael S

    2016-02-23

    Zinc oxide (ZnO) is frequently used in commercial sunscreen formulations to deliver their broad range of UV protection properties. Concern has been raised about the extent to which these ZnO particles (both micronized and nanoparticulate) penetrate the skin and their resultant toxicity. This work has explored the human epidermal skin penetration of zinc oxide and its labile zinc ion dissolution product that may potentially be formed after application of ZnO nanoparticles to human epidermis. Three ZnO nanoparticle formulations were used: a suspension in the oil, capric caprylic triglycerides (CCT), the base formulation commonly used in commercially available sunscreen products; an aqueous ZnO suspension at pH 6, similar to the natural skin surface pH; and an aqueous ZnO suspension at pH 9, a pH at which ZnO is stable and there is minimal pH-induced impairment of epidermal integrity. In each case, the ZnO in the formulations did not penetrate into the intact viable epidermis for any of the formulations but was associated with an enhanced increase in zinc ion fluorescence signal in both the stratum corneum and the viable epidermis. The highest labile zinc fluorescence was found for the ZnO suspension at pH 6. It is concluded that, while topically applied ZnO does not penetrate into the viable epidermis, these applications are associated with hydrolysis of ZnO on the skin surface, leading to an increase in zinc ion levels in the stratum corneum, thence in the viable epidermis and subsequently in the systemic circulation and the urine.

  16. Antifouling properties of zinc oxide nanorod coatings.

    PubMed

    Al-Fori, Marwan; Dobretsov, Sergey; Myint, Myo Tay Zar; Dutta, Joydeep

    2014-01-01

    In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10 mM) of zinc precursors. These coatings were tested for 5 h under artificial sunlight (1060 W m(-2) or 530 W m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn(2+) ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions.

  17. Review of Zinc Oxide Thin Films

    DTIC Science & Technology

    2014-12-23

    Laboratory Air Force Materiel Command   a. REPORT U   b. ABSTRACT U   c. THIS PAGE U REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188 The public...PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. 1.  REPORT DATE (DD-MM-YYYY)      18-12-2014 2.  REPORT TYPE      Final Performance 3.  DATES...Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 1    Review of Zinc Oxide Thin Films   Abstract  The present review paper reports on the

  18. Sprayed lanthanum doped zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Bouznit, Y.; Beggah, Y.; Ynineb, F.

    2012-01-01

    Lanthanum doped zinc oxide thin films were deposited on soda-lime glass substrates using a pneumatic spray pyrolysis technique. The films were prepared using different lanthanum concentrations at optimum deposition parameters. We studied the variations in structural, morphological and optical properties of the samples due to the change of doping concentration in precursor solutions. X-ray diffraction (XRD) patterns show that pure and La-doped ZnO thin films are highly textured along c-axis perpendicular to the surface of the substrate. Scanning electron micrographs show that surface morphology of ZnO films undergoes a significant change according to lanthanum doping. All films exhibit a transmittance higher than 80% in the visible region.

  19. Photocatalytic paper using zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Baruah, Sunandan; Jaisai, Mayuree; Imani, Reza; Nazhad, Mousa M.; Dutta, Joydeep

    2010-10-01

    Zinc oxide (ZnO) nanorods were grown on a paper support prepared from soft wood pulp. The photocatalytic activity of a sheet of paper with ZnO nanorods embedded in its porous matrix has been studied. ZnO nanorods were firmly attached to cellulose fibers and the photocatalytic paper samples were reused several times with nominal decrease in efficiency. Photodegradation of up to 93% was observed for methylene blue in the presence of paper filled with ZnO nanorods upon irradiation with visible light at 963 Wm-2 for 120 min. Under similar conditions, photodegradation of approximately 35% was observed for methyl orange. Antibacterial tests revealed that the photocatalytic paper inhibits the growth of Escherichia coli under room lighting conditions.

  20. Photocatalytic paper using zinc oxide nanorods

    PubMed Central

    Baruah, Sunandan; Jaisai, Mayuree; Imani, Reza; Nazhad, Mousa M; Dutta, Joydeep

    2010-01-01

    Zinc oxide (ZnO) nanorods were grown on a paper support prepared from soft wood pulp. The photocatalytic activity of a sheet of paper with ZnO nanorods embedded in its porous matrix has been studied. ZnO nanorods were firmly attached to cellulose fibers and the photocatalytic paper samples were reused several times with nominal decrease in efficiency. Photodegradation of up to 93% was observed for methylene blue in the presence of paper filled with ZnO nanorods upon irradiation with visible light at 963 Wm–2 for 120 min. Under similar conditions, photodegradation of approximately 35% was observed for methyl orange. Antibacterial tests revealed that the photocatalytic paper inhibits the growth of Escherichia coli under room lighting conditions. PMID:27877367

  1. Zinc

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc was recognized as an essential trace metal for humans during the studies of Iranian adolescent dwarfs in the early 1960s. Zinc metal existing as Zn2+ is a strong electron acceptor in biological systems without risks of oxidant damage to cells. Zn2+ functions in the structure of proteins and is ...

  2. Microwave Synthesis of Zinc Hydroxy Sulfate Nanoplates and Zinc Oxide Nanorods in the Classroom

    ERIC Educational Resources Information Center

    Dziedzic, Rafal M.; Gillian-Daniel, Anne Lynn; Peterson, Greta M.; Martínez-Herna´ndez, Kermin J.

    2014-01-01

    In this hands-on, inquiry-based lab, high school and undergraduate students learn about nanotechnology by synthesizing their own nanoparticles in a single class period. This simple synthesis of zinc oxide nanorods and zinc hydroxy sulfate nanoplates can be done in 15 min using a household microwave oven. Reagent concentration, reaction…

  3. Liquid crystallinity driven highly aligned large graphene oxide composites

    SciTech Connect

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong; Kim, Sang Ouk

    2015-04-15

    Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

  4. Surface nature of nanoparticle zinc-titanium oxide aerogel catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Chien-Tsung; Lin, Jen-Chieh

    2008-05-01

    Nanoparticle zinc-titanium oxide materials were prepared by the aerogel approach. Their structure, surface state and reactivity were investigated. Zinc titanate powders formed at higher zinc loadings possessed a higher surface area and smaller particle size. X-ray photoelectron spectroscopy (XPS) revealed a stronger electronic interaction between Zn and Ti atoms in the mixed oxide structure and showed the formation of oxygen vacancy due to zinc doping into titania or zinc titanate matrices. The 8-45 nm aerogel particles were evaluated as catalysts for methanol oxidation in an ambient flow reactor. Carbon dioxide was favorably produced on the oxides with anion defects. Titanium based oxides exhibited a high selectivity to dimethyl ether, so that a strong Lewis acidic character suggested for the catalysts was associated primarily with the Ti 4+ center. Both methanol conversion and dimethyl ether formation rates increased with increasing the zinc content added to the oxide support. Results demonstrate that cubic zinc titanate phases produce new Lewis acid sites having also a higher reactivity and that the nature of the catalytic surface transforms from Lewis acidic to basic characters due to the presence of reactive oxygen vacancies.

  5. Toxicokinetics of zinc oxide nanoparticles in rats

    NASA Astrophysics Data System (ADS)

    Chung, H. E.; Yu, J.; Baek, M.; Lee, J. A.; Kim, M. S.; Kim, S. H.; Maeng, E. H.; Lee, J. K.; Jeong, J.; Choi, S. J.

    2013-04-01

    Zinc oxide (ZnO) nanoparticle have been extensively applied to diverse industrial fields because they possess UV light absorption, catalytic, semi-conducting, and magnetic characteristics as well as antimicrobial property. However, up to date, toxicological effects of ZnO nanoparticles in animal models have not been completely determined. Moreover, little information is available about kinetic behaviors of ZnO nanoparticles in vivo, which will be crucial to predict their potential chronic toxicity after long-term exposure. The aim of this study was, therefore, to evaluate the pharmacokinetics and toxicokinetics of ZnO nanoparticles after single-dose and repeated dose 90-day oral administration in male and female rats, respectively. The blood samples were collected following administration of three different doses (125, 250, and 500 mg/kg) and ZnO concentration was assessed by measuring zinc level with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that the plasma ZnO concentration significantly increased in a dose-dependent manner, but decreased within 24 h after single-dose oral administration up to 500 mg/kg, without any significant difference between gender. However, when repeated dose 90-day oral toxicity study was performed, the elevated plasma concentrations did not return to normal control levels in all the cases, indicating their toxicity potential. These findings suggest that repeated oral exposure to ZnO nanoparticles up to the dose of 125 mg/kg could accumulate in the systemic circulation, thereby implying that the NOAEL values could be less than 125 mg/kg via oral intake.

  6. Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide

    PubMed Central

    Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria

    2014-01-01

    The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

  7. A review of zinc oxide mineral beneficiation using flotation method.

    PubMed

    Ejtemaei, Majid; Gharabaghi, Mahdi; Irannajad, Mehdi

    2014-04-01

    In recent years, extraction of zinc from low-grade mining tailings of oxidized zinc has been a matter of discussion. This is a material which can be processed by flotation and acid-leaching methods. Owing to the similarities in the physicochemical and surface chemistry of the constituent minerals, separation of zinc oxide minerals from their gangues by flotation is an extremely complex process. It appears that selective leaching is a promising method for the beneficiation of this type of ore. However, with the high consumption of leaching acid, the treatment of low-grade oxidized zinc ores by hydrometallurgical methods is expensive and complex. Hence, it is best to pre-concentrate low-grade oxidized zinc by flotation and then to employ hydrometallurgical methods. This paper presents a critical review on the zinc oxide mineral flotation technique. In this paper, the various flotation methods of zinc oxide minerals which have been proposed in the literature have been detailed with the aim of identifying the important factors involved in the flotation process. The various aspects of recovery of zinc from these minerals are also dealt with here. The literature indicates that the collector type, sulfidizing agent, pH regulator, depressants and dispersants types, temperature, solid pulp concentration, and desliming are important parameters in the process. The range and optimum values of these parameters, as also the adsorption mechanism, together with the resultant flotation of the zinc oxide minerals reported in the literature are summarized and highlighted in the paper. This review presents a comprehensive scientific guide to the effectiveness of flotation strategy.

  8. Paramagnetic dysprosium-doped zinc oxide thin films grown by pulsed-laser deposition

    SciTech Connect

    Lo, Fang-Yuh Ting, Yi-Chieh; Chou, Kai-Chieh; Hsieh, Tsung-Chun; Ye, Cin-Wei; Hsu, Yung-Yuan; Liu, Hsiang-Lin; Chern, Ming-Yau

    2015-06-07

    Dysprosium(Dy)-doped zinc oxide (Dy:ZnO) thin films were fabricated on c-oriented sapphire substrate by pulsed-laser deposition with doping concentration ranging from 1 to 10 at. %. X-ray diffraction (XRD), Raman-scattering, optical transmission spectroscopy, and spectroscopic ellipsometry revealed incorporation of Dy into ZnO host matrix without secondary phase. Solubility limit of Dy in ZnO under our deposition condition was between 5 and 10 at. % according to XRD and Raman-scattering characteristics. Optical transmission spectroscopy and spectroscopic ellipsometry also showed increase in both transmittance in ultraviolet regime and band gap of Dy:ZnO with increasing Dy density. Zinc vacancies and zinc interstitials were identified by photoluminescence spectroscopy as the defects accompanied with Dy incorporation. Magnetic investigations with a superconducting quantum interference device showed paramagnetism without long-range order for all Dy:ZnO thin films, and a hint of antiferromagnetic alignment of Dy impurities was observed at highest doping concentration—indicating the overall contribution of zinc vacancies and zinc interstitials to magnetic interaction was either neutral or toward antiferromagnetic. From our investigations, Dy:ZnO thin films could be useful for spin alignment and magneto-optical applications.

  9. Paramagnetic dysprosium-doped zinc oxide thin films grown by pulsed-laser deposition

    NASA Astrophysics Data System (ADS)

    Lo, Fang-Yuh; Ting, Yi-Chieh; Chou, Kai-Chieh; Hsieh, Tsung-Chun; Ye, Cin-Wei; Hsu, Yung-Yuan; Chern, Ming-Yau; Liu, Hsiang-Lin

    2015-06-01

    Dysprosium(Dy)-doped zinc oxide (Dy:ZnO) thin films were fabricated on c-oriented sapphire substrate by pulsed-laser deposition with doping concentration ranging from 1 to 10 at. %. X-ray diffraction (XRD), Raman-scattering, optical transmission spectroscopy, and spectroscopic ellipsometry revealed incorporation of Dy into ZnO host matrix without secondary phase. Solubility limit of Dy in ZnO under our deposition condition was between 5 and 10 at. % according to XRD and Raman-scattering characteristics. Optical transmission spectroscopy and spectroscopic ellipsometry also showed increase in both transmittance in ultraviolet regime and band gap of Dy:ZnO with increasing Dy density. Zinc vacancies and zinc interstitials were identified by photoluminescence spectroscopy as the defects accompanied with Dy incorporation. Magnetic investigations with a superconducting quantum interference device showed paramagnetism without long-range order for all Dy:ZnO thin films, and a hint of antiferromagnetic alignment of Dy impurities was observed at highest doping concentration—indicating the overall contribution of zinc vacancies and zinc interstitials to magnetic interaction was either neutral or toward antiferromagnetic. From our investigations, Dy:ZnO thin films could be useful for spin alignment and magneto-optical applications.

  10. The kinetic of photoreactions in zinc oxide microrods

    NASA Astrophysics Data System (ADS)

    Fiedot, M.; Rac, O.; Suchorska-Woźniak, P.; Nawrot, W.; Teterycz, H.

    2016-01-01

    Zinc oxide is the oldest sensing material used in the chemical resistive gas sensors which allow to detect many gases, such as carbon oxide, nitrogen oxides and other. This material is also widely used in medicine and daily life as antibacterial agent. For this reason this semiconductor is often synthesized on the polymer substrates such as foils and textiles. In presented results zinc oxide was deposited on the surface of poly(ethylene terephthalate) foil to obtain antibacterial material. As synthesis method chemical bath deposition was chosen. The growth of zinc oxide structures was carried out in water solution of zinc nitrate (V) and hexamethylenetetramine in 90°C during 9 h. Because antibacterial properties of ZnO are strongly depended on photocatalytic and electric properties of this semiconductor impedance spectroscopy measurements were carried out. During the measurements material was tested with and without UV light to determinate the kinetic of photoreactions in zinc oxide. Moreover the composite was analyzed by XRD diffraction and scanning electron microscope. The X-ray analysis indicated that obtained material has the structure of wurtzite which is typical of zinc oxide. SEM images showed that on the PET foil microrods of ZnO were formed. The impedance spectroscopy measurements of ZnO layer showed that in UV light significant changes in the conductivity of the material are observed.

  11. Zinc oxide nanoflowers make new blood vessels

    NASA Astrophysics Data System (ADS)

    Barui, Ayan Kumar; Veeriah, Vimal; Mukherjee, Sudip; Manna, Joydeb; Patel, Ajay Kumar; Patra, Sujata; Pal, Krishnendu; Murali, Shruthi; Rana, Rohit K.; Chatterjee, Suvro; Patra, Chitta Ranjan

    2012-11-01

    It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role.It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood

  12. Acetone sensor based on zinc oxide hexagonal tubes

    SciTech Connect

    Hastir, Anita Singh, Onkar Anand, Kanika Singh, Ravi Chand

    2014-04-24

    In this work hexagonal tubes of zinc oxide have been synthesized by co-precipitation method. For structural, morphological, elemental and optical analysis synthesized powders were characterized by using x-ray diffraction, field emission scanning microscope, EDX, UV-visible and FTIR techniques. For acetone sensing thick films of zinc oxide have been deposited on alumina substrate. The fabricated sensors exhibited maximum sensing response towards acetone vapour at an optimum operating temperature of 400°C.

  13. Electrochemical synthesis and characterization of zinc carbonate and zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pourmortazavi, Seied Mahdi; Marashianpour, Zahra; Karimi, Meisam Sadeghpour; Mohammad-Zadeh, Mohammad

    2015-11-01

    Zinc oxide and its precursor i.e., zinc carbonate is widely utilized in various fields of industry, especially in solar energy conversion, optical, and inorganic pigments. In this work, a facile and clean electrodeposition method was utilized for the synthesis of zinc carbonate nanoparticles. Also, zinc oxide nanoparticles were produced by calcination of the prepared zinc carbonate powder. Zinc carbonate nanoparticles with different sizes were electrodeposited by electrolysis of a zinc plate as anode in the solution of sodium carbonate. It was found that the particle size of zinc carbonate might be tuned by process parameters, i.e., electrolysis voltage, carbonate ion concentration, solvent composition and stirring rate of the electrolyte solution. An orthogonal array design was utilized to identify the optimum experimental conditions. The experimental results showed that the minimum size of the electrodeposited ZnCO3 particles is about 24 nm whereas the maximum particle size is around 40 nm. The TG-DSC studies of the nanoparticles indicated that the main thermal degradation of ZnCO3 occurs in two steps over the temperature ranges of 150-250 and 350-400 °C. The electrosynthesized ZnCO3 nanoparticles were calcined at the temperature of 600 °C to prepare ZnO nanoparticles. The prepared ZnCO3 and ZnO nanoparticles were characterized by SEM, X-ray diffraction (XRD), and FT-IR techniques.

  14. Biomedical Applications of Zinc Oxide Nanomaterials

    PubMed Central

    Zhang, Yin; Nayak, Tapas R.; Hong, Hao; Cai, Weibo

    2013-01-01

    Nanotechnology has witnessed tremendous advancement over the last several decades. Zinc oxide (ZnO), which can exhibit a wide variety of nanostructures, possesses unique semiconducting, optical, and piezoelectric properties hence has been investigated for a wide variety of applications. One of the most important features of ZnO nanomaterials is low toxicity and biodegradability. Zn2+ is an indispensable trace element for adults (~10 mg of Zn2+ per day is recommended) and it is involved in various aspects of metabolism. Chemically, the surface of ZnO is rich in -OH groups, which can be readily functionalized by various surface decorating molecules. In this review article, we summarized the current status of the use of ZnO nanomaterials for biomedical applications, such as biomedical imaging (which includes fluorescence, magnetic resonance, positron emission tomography, as well as dual-modality imaging), drug delivery, gene delivery, and biosensing of a wide array of molecules of interest. Research in biomedical applications of ZnO nanomaterials will continue to flourish over the next decade, and much research effort will be needed to develop biocompatible/biodegradable ZnO nanoplatforms for potential clinical translation. PMID:24206130

  15. Liquid crystallinity driven highly aligned large graphene oxide composites

    NASA Astrophysics Data System (ADS)

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong; Kim, Sang Ouk

    2015-04-01

    Graphene is an emerging graphitic carbon materials, consisting of sp2 hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites.

  16. [Zinc oxide-eugenol as dental material (1)].

    PubMed

    Brauer, G M

    1976-11-01

    Zinc oxide-eugenol cements are considerably better tolerated by tissue than other dental materials. As they alleviate pain and are bacteriostatic and antiseptic, they are well tolerated by patients. The cements are good insulators and possess better sealing properties than zinc phosphate cements. Because of their poor mechanic properties, the conventional zinc oxide-eugenol cements are mainly used as temporary fixing contents and filling materials, for gingival dressings and together with filling materials as impression materials. Recently, reinforced zinc oxide-eugenol cements and cements containing ethoxy benzoic acid (EBA) have been developed. These new cements have considerably better mechanic properties and are therefore used for cement bases, indirect capping, long-term temporary fillings and in selected cases as definite fixing cements.

  17. Synthesis of europium-doped zinc oxide micro- and nanowires

    NASA Astrophysics Data System (ADS)

    Al Rifai, S. A.; Ryabtsev, S. V.; Smirnov, M. S.; Domashevskaya, E. P.; Ivanov, O. N.

    2014-01-01

    Single crystalline Eu3+-doped wurtzite ZnO micro- and nanowires were synthesized by a chemical vapor deposition method (CVD). The nanostructures were grown by autocatalytic mechanism at walls of an alumina boat. The structure and properties of the doped ZnO is fully characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), scanning and transmission electron microscopy (SEM and TEM), and photoluminescence (PL) methods. The synthesis was carried out for 10 min giving vertically aligned nanowires with mean diameter of 50-400 nm and with length of up to several microns. The nanowires were grown along ±[0001] direction. The concentration of Eu3+ dopant in the synthesized nanowires was varied from 0.7 to 0.9 at %. The crystal structure and microstructures of the doped nanomaterials were discussed and compared with undoped ZnO. The photoluminescence spectra show that emission of doped samples were shifted towards orange-red region (2.02 eV) relative to undoped zinc oxide nanostructures (2.37 eV) due to Eu3+ intraionic transitions from ZnO/Eu.

  18. Synthesis, characterization and catalytic application of polyhedron zinc oxide microparticles

    NASA Astrophysics Data System (ADS)

    Jamil, Saba; Ramzan Saeed Ashraf Janjua, Muhammad; Khan, Shanza Rauf; Jahan, Nazish

    2017-01-01

    Zinc oxide (ZnO) microparticles of unique morphology were synthesized by the microwave heating method. The composition and morphology of the synthesized microparticles were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is clear from the XRD pattern that the product is highly pure and crystalline. It is shown from the SEM images that the hexagonal unit cells are arranged in the form of a polyhedral lattice. The length of the sides is equal at the middle of the lattice, and unequal on the terminal sides of the lattice. This is due to the alignment of the hexagonal unit cells. The size distribution histogram of the product possesses a sharp band which shows that it is monodisperse. This means that a monodisperse product can be obtained by the microwave heating method. The synthesized particles were used as a catalyst for the thermal degradation of ammonium perchlorate (AP) and the catalytic reduction of 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP). The effect of temperature on the value of the apparent rate constant was also studied, and the values of the kinetic and thermodynamic parameters were calculated. This shows that the catalyst possesses high efficiency for thermally degrading of substances at low temperatures and rapidly reducing the nitroarenes in an aqueous medium.

  19. Genotoxic effects of zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Heim, Julia; Felder, Eva; Tahir, Muhammad Nawaz; Kaltbeitzel, Anke; Heinrich, Ulf Ruediger; Brochhausen, Christoph; Mailänder, Volker; Tremel, Wolfgang; Brieger, Juergen

    2015-05-01

    The potential toxicity of nanoparticles has currently provoked public and scientific discussions, and attempts to develop generally accepted handling procedures for nanoparticles are under way. The investigation of the impact of nanoparticles on human health is overdue and reliable test systems accounting for the special properties of nanomaterials must be developed. Nanoparticular zinc oxide (ZnO) may be internalised through ambient air or the topical application of cosmetics, only to name a few, with unpredictable health effects. Therefore, we analysed the determinants of ZnO nanoparticle (NP) genotoxicity. ZnO NPs (15-18 nm in diameter) were investigated at concentrations of 0.1, 10 and 100 μg mL-1 using the cell line A549. Internalised NPs were only infrequently detectable by TEM, but strongly increased Zn2+ levels in the cytoplasm and even more in the nuclear fraction, as measured by atom absorption spectroscopy, indicative of an internalised zinc and nuclear accumulation. We observed a time and dosage dependent reduction of cellular viability after ZnO NP exposure. ZnCl2 exposure to cells induced similar impairments of cellular viability. Complexation of Zn2+ with diethylene triamine pentaacetic acid (DTPA) resulted in the loss of toxicity of NPs, indicating the relevant role of Zn2+ for ZnO NP toxicity. Foci analyses showed the induction of DNA double strand breaks (DSBs) by ZnO NPs and increased intracellular reactive oxygen species (ROS) levels. Treatment of the cells with the ROS scavenger N-acetyl-l-cysteine (NAC) resulted in strongly decreased intracellular ROS levels and reduced DNA damage. However, a slow increase of ROS after ZnO NP exposure and reduced but not quashed DSBs after NAC-treatment suggest that Zn2+ may exert genotoxic activities without the necessity of preceding ROS-induction. Our data indicate that ZnO NP toxicity is a result of cellular Zn2+ intake. Subsequently increased ROS-levels cause DNA damage. However, we found evidence for

  20. Synthetic silver oxide and mercury-free zinc electrodes for silver-zinc reserve batteries

    NASA Astrophysics Data System (ADS)

    Smith, David F.; Gucinski, James A.

    Reserve activated silver oxide-zinc cells were constructed with synthetic silver oxide (Ag 2O) electrodes with Pb-treated zinc electrodes produced by a non-electrolytic process. The cells were tested before and after thermally accelerated aging. At discharge rates up to 80 mA cm -2, the discharge was limited by the Ag 2O electrode, with a coulombic efficiency between 89-99%. At higher rates, the cells are apparently zinc-limited. Test cells were artificially aged at 90°C for 19 h and discharged at 21°C at 80 mA cm -2. No capacity loss was measured, but a delayed activation rise time was noted (192 ms fresh vs. 567 ms aged). The delay is thought to be caused by zinc passivation due to the outgassing of cell materials.

  1. Thermodynamics and kinetics of extracting zinc from zinc oxide ore by the ammonium sulfate roasting method

    NASA Astrophysics Data System (ADS)

    Sun, Yi; Shen, Xiao-yi; Zhai, Yu-chun

    2015-05-01

    Thermodynamic analyses and kinetic studies were performed on zinc oxide ore treatment by (NH4)2SO4 roasting technology. The results show that it is theoretically feasible to realize a roasting reaction between the zinc oxide ore and (NH4)2SO4 in a temperature range of 573-723 K. The effects of reaction temperature and particle size on the extraction rate of zinc were also examined. It is found that a surface chemical reaction is the rate-controlling step in roasting kinetics. The calculated activation energy of this process is about 45.57 kJ/mol, and the kinetic model can be expressed as follows: 1 - (1 - α)1/3 = 30.85 exp(-45.57/ RT)· t. An extraction ratio of zinc as high as 92% could be achieved under the optimum conditions.

  2. Zinc-oxide-based nanostructured materials for heterostructure solar cells

    SciTech Connect

    Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A. Somov, P. A.; Terukov, E. I.

    2015-10-15

    Results obtained in the deposition of nanostructured zinc-oxide layers by hydrothermal synthesis as the basic method are presented. The possibility of controlling the structure and morphology of the layers is demonstrated. The important role of the procedure employed to form the nucleating layer is noted. The faceted hexagonal nanoprisms obtained are promising for the fabrication of solar cells based on oxide heterostructures, and aluminum-doped zinc-oxide layers with petal morphology, for the deposition of an antireflection layer. The results are compatible and promising for application in flexible electronics.

  3. Growth and electrical properties of zinc oxide nanowires.

    PubMed

    Zhang, Zengxing; Zhao, Yuanchun; Sun, Lianfeng; Liu, Dongfang; Shen, Jun; Zhou, Weiya; Luo, Qiang; Jin, Aizi; Yang, Haifang; Gu, Changzhi; Xie, Sishen

    2009-02-01

    Zinc oxide nanowires were grown on molybdenum grids with a simple chemical vapor transport and deposition method through thermal evaporation of zinc powder at a temperature of 600 degrees C. These nanowires are 20-50 nm in diameter and over ten microns in length. High resolution transmission electron microscopy studies show that the as-grown nanowires are single crystal of wurtzite structure and grow along the (0001) direction. The growth process was explained with a vapor-solid mechanism under zinc-rich conditions. We further patterned electrodes on individual ZnO nanowires by e-beam lithography and studied thier electrical properties.

  4. Defects and ferromagnetism in transition metal doped zinc oxide

    NASA Astrophysics Data System (ADS)

    Thapa, Sunil

    Transition metal doped zinc oxide has been studied recently due to its potential application in spintronic devices. The magnetic semiconductor, often called Diluted Magnetic Semiconductors (DMS), has the ability to incorporate both charge and spin into a single formalism. Despite a large number of studies on ferromagnetism in ZnO based DMS and the realization of its room temperature ferromagnetism, there is still a debate about the origin of the ferromagnetism. In this work, the synthesis and characterization of transition metal doped zinc oxide have been carried out. The sol-gel method was used to synthesize thin films, and they were subsequently annealed in air. Characterization of doped zinc oxide films was carried out using the UV-visible range spectrometer, scanning electron microscopy, superconducting quantum interference device (SQUID), x-ray diffraction(XRD) and positron annihilation spectroscopy. Hysteresis loops were obtained for copper and manganese doped zinc oxide, but a reversed hysteresis loop was observed for 2% Al 3% Co doped zinc oxide. The reversed hysteresis loop has been explained using a two-layer model.

  5. Plasma in-liquid method for reduction of zinc oxide in zinc nanoparticle synthesis

    NASA Astrophysics Data System (ADS)

    Amaliyah, Novriany; Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi; Kitamae, Tomohide

    2015-02-01

    Metal air-batteries with high-energy density are expected to be increasingly applied in electric vehicles. This will require a method of recycling air batteries, and reduction of metal oxide by generating plasma in liquid has been proposed as a possible method. Microwave-induced plasma is generated in ethanol as a reducing agent in which zinc oxide is dispersed. Analysis by energy-dispersive x-ray spectrometry (EDS) and x-ray diffraction (XRD) reveals the reduction of zinc oxide. According to images by transmission electron microscopy (TEM), cubic and hexagonal metallic zinc particles are formed in sizes of 30 to 200 nm. Additionally, spherical fiber flocculates approximately 180 nm in diameter are present.

  6. Fundamentals of zinc oxide as a semiconductor

    NASA Astrophysics Data System (ADS)

    Janotti, Anderson; Van de Walle, Chris G.

    2009-12-01

    In the past ten years we have witnessed a revival of, and subsequent rapid expansion in, the research on zinc oxide (ZnO) as a semiconductor. Being initially considered as a substrate for GaN and related alloys, the availability of high-quality large bulk single crystals, the strong luminescence demonstrated in optically pumped lasers and the prospects of gaining control over its electrical conductivity have led a large number of groups to turn their research for electronic and photonic devices to ZnO in its own right. The high electron mobility, high thermal conductivity, wide and direct band gap and large exciton binding energy make ZnO suitable for a wide range of devices, including transparent thin-film transistors, photodetectors, light-emitting diodes and laser diodes that operate in the blue and ultraviolet region of the spectrum. In spite of the recent rapid developments, controlling the electrical conductivity of ZnO has remained a major challenge. While a number of research groups have reported achieving p-type ZnO, there are still problems concerning the reproducibility of the results and the stability of the p-type conductivity. Even the cause of the commonly observed unintentional n-type conductivity in as-grown ZnO is still under debate. One approach to address these issues consists of growing high-quality single crystalline bulk and thin films in which the concentrations of impurities and intrinsic defects are controlled. In this review we discuss the status of ZnO as a semiconductor. We first discuss the growth of bulk and epitaxial films, growth conditions and their influence on the incorporation of native defects and impurities. We then present the theory of doping and native defects in ZnO based on density-functional calculations, discussing the stability and electronic structure of native point defects and impurities and their influence on the electrical conductivity and optical properties of ZnO. We pay special attention to the possible causes

  7. Crystalline state and acoustic properties of zinc oxide films

    SciTech Connect

    Kal'naya, G.I.; Pryadko, I.F.; Yarovoi, Yu.A.

    1988-08-01

    We study the effect of the crystalline state of zinc oxide films, prepared by magnetron sputtering, on the efficiency of SAW transducers based on the layered system textured ZnO film-interdigital transducer (IDT)-fused quartz substrate. The crystalline perfection of the ZnO films was studied by the x-ray method using a DRON-2.0 diffractometer. The acoustic properties of the layered system fused quartz substrate-IDT-zinc oxide film were evaluated based on the squared electromechanical coupling constant K/sup 2/ for strip filters. It was found that K/sup 2/ depends on the magnitude of the mechanical stresses. When zinc oxide films are deposited by the method of magnetron deposition on fused quartz substrates, depending on the process conditions limitations can arise on the rate of deposition owing to mechanical stresses, which significantly degrade the efficiency of SAW transducers based on them, in the ZnO films.

  8. Zinc Oxide Nanoparticles for Revolutionizing Agriculture: Synthesis and Applications

    PubMed Central

    Sabir, Sidra; Arshad, Muhammad

    2014-01-01

    Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles. PMID:25436235

  9. Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pike, Sebastian D.; White, Edward R.; Shaffer, Milo S. P.; Williams, Charlotte K.

    2016-10-01

    The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2-4 nm) nanoparticles.

  10. Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach

    NASA Astrophysics Data System (ADS)

    Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; van Dorsselaer, Alain; Rabilloud, Thierry

    2014-05-01

    Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate

  11. Biomineralization-Inspired Preparation of Zinc Hydroxide Carbonate/Polymer Hybrids and Their Conversion into Zinc Oxide Thin-Film Photocatalysts.

    PubMed

    Matsumura, Shunichi; Horiguchi, Yoshimasa; Nishimura, Tatsuya; Sakai, Hideki; Kato, Takashi

    2016-05-17

    The development of ZnO thin films has been achieved through the conversion of zinc hydroxide carbonate thin-film crystals. Crystallization of this compound is induced by a biomineralization-inspired method with polymer-stabilized amorphous precursors. The crystals grow radially on polymer matrices, leading to the formation of zinc hydroxide carbonate/polymer thin-film hybrids that fully cover the substrate. These hybrids are converted into ZnO and retain their thin-film morphologies. The resultant ZnO thin films exhibit a preferential crystallographic orientation that is attributed to the alignment of zinc hydroxide carbonate crystals before conversion. In addition, a photocatalytic function of the ZnO thin films has been demonstrated by analyzing the oxidation reaction of 2-propanol. The biomineralization-inspired approach reported herein is a promising way to develop ZnO materials with controlled morphologies and structures for photocatalytic applications.

  12. Hydrogen Reduction of Zinc and Iron Oxides Containing Mixtures

    NASA Astrophysics Data System (ADS)

    de Siqueira, Rogério Navarro C.; de Albuquerque Brocchi, Eduardo; de Oliveira, Pamela Fernandes; Motta, Marcelo Senna

    2013-10-01

    Zinc is a metal of significant technological importance and its production from secondary sources has motivated the development of alternative processes, such as the chemical treatment of electrical arc furnace (EAF) dust. Currently, the extraction of zinc from the mentioned residue using a carbon-containing reducing agent is in the process of being established commercially and technically. In the current study, the possibility of reducing zinc from an EAF dust sample through a H2 constant flux in a horizontal oven is studied. The reduction of a synthetic oxide mixture of analogous composition is also investigated. The results indicated that the reduction process is thermodynamically viable for temperatures higher than 1123 K (850 °C), and all zinc metal produced is transferred to the gas stream, enabling its complete separation from iron. The same reaction in the presence of zinc crystals was considered for synthesizing FeZn alloys. However, for the experimental conditions employed, although ZnO reduction was indeed thermodynamically hindered because of the presence of zinc crystals (the metal's partial pressure was enhanced), the zinc metal's escape within the gaseous phase could not be effectively avoided.

  13. Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide

    NASA Astrophysics Data System (ADS)

    Acarali, Nil Baran; Bardakci, Melek; Tugrul, Nurcan; Derun, Emek Moroydor; Piskin, Sabriye

    2013-06-01

    The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1-5 h), reactant ratio (H3BO3/ZnO by mass: 2-5), seed ratio (seed crystal/(H3BO3+ZnO) by mass: 0-2wt%), reaction temperature (50-120°C), cooling temperature (10-80°C), and stirring rate (400-700 r/min); the modifying agents involve propylene glycol (PG, 0-6wt%), kerosene (1wt%-6wt%), and oleic acid (OA, 1wt%-6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.

  14. Process for fabricating doped zinc oxide microsphere gel

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1991-11-05

    Disclosed are a new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  15. Process for fabricating doped zinc oxide microsphere gel

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1991-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  16. Chemical vapor deposition of fluorine-doped zinc oxide

    DOEpatents

    Gordon, Roy G.; Kramer, Keith; Liang, Haifan

    2000-06-06

    Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

  17. Zinc oxide nanorods functionalized paper for protein preconcentration in biodiagnostics.

    PubMed

    Tiwari, Sadhana; Vinchurkar, Madhuri; Rao, V Ramgopal; Garnier, Gil

    2017-03-02

    Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept.

  18. Investigation of Optical Properties of Zinc Oxide Photodetector

    NASA Astrophysics Data System (ADS)

    Chism, Tyler

    UV photodetection devices have many important applications for uses in biological detection, gas sensing, weaponry detection, fire detection, chemical analysis, and many others. Today's photodetectors often utilize semiconductors such as GaAs to achieve high responsivity and sensitivity. Zinc oxide, unlike many other semiconductors, is cheap, abundant, non-toxic, and easy to grow different morphologies at the micro and nano scale. With the proliferation of these devices also comes the impending need to further study optics and photonics in relation to phononics and plasmonics, and the general principles underlying the interaction of photons with solid state matter and, specifically, semiconductors. For this research a metal-semiconductor-metal UV photodetector has been fabricated by using a quartz substrate on top of which was deposited micropatterned gold in an interdigitated electrode design. On this, sparsely coated zinc oxide nano trees were hydrothermally grown. The UV photodetection device showed promise for detection applications, especially because zinc oxide is also very thermally stable, a quality which is highly sought after in today's UV photodetectors. Furthermore, the newly synthesized photodetector was used to investigate optical properties and how they respond to different stimuli. It was discovered that the photons transmitted through the sparsely coated zinc oxide nano trees decreased as the voltage across the device increased. This research is aimed at better understanding photons interaction with matter and also to open the door for new devices with tunable optical properties such as transmission.

  19. Zinc oxide nanorods functionalized paper for protein preconcentration in biodiagnostics

    NASA Astrophysics Data System (ADS)

    Tiwari, Sadhana; Vinchurkar, Madhuri; Rao, V. Ramgopal; Garnier, Gil

    2017-03-01

    Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept.

  20. Interfacial electron transfer dynamics of photosensitized zinc oxide nanoclusters

    SciTech Connect

    Murakoshi, Kei; Yanagida, Shozo; Capel, M.

    1997-06-01

    The authors have prepared and characterized photosensitized zinc oxide (ZnO) nanoclusters, dispersed in methanol, using carboxylated coumarin dyes for surface adsorption. Femtosecond time-resolved emission spectroscopy allows the authors to measure the photo-induced charge carrier injection rate constant from the adsorbed photosensitizer to the n-type semiconductor nanocluster. These results are compared with other photosensitized semiconductors.

  1. Application of zinc oxide quantum dots in food safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc oxide quantum dots (ZnO QDs) are nanoparticles of purified powdered ZnO. The ZnO QDs were directly added into liquid foods or coated on the surface of glass jars using polylactic acid (PLA) as a carrier. The antimicrobial activities of ZnO QDs against Listeria monocytogenes, Salmonella Enteriti...

  2. Zinc oxide nanorods functionalized paper for protein preconcentration in biodiagnostics

    PubMed Central

    Tiwari, Sadhana; Vinchurkar, Madhuri; Rao, V. Ramgopal; Garnier, Gil

    2017-01-01

    Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept. PMID:28252113

  3. Antibacterial Activity of Zinc Oxide-Coated Nanoporous Alumina

    DTIC Science & Technology

    2012-05-17

    2012 Available online 17 May 2012 Keywords: Aluminum oxide Zinc oxide Atomic layer deposition Nanoporous material Antibacterial material a b s t r...standard and mixed online with each sample through a tee. Isotopes (e.g., 66Zn and 115In) were evaluated in a peak hop- ping mode; a dwell time of...20 pore sizes nm and (n) 100 nm pore sizes that were examined against Staphylococcus epidermidis. several potential dermatologic applications for

  4. Zinc oxide nanolevel surface transformation for liquid crystal orientation by ion bombardment

    SciTech Connect

    Oh, Byeong-Yun; Lee, Won-Kyu; Kim, Young-Hwan; Seo, Dae-Shik

    2009-03-01

    This paper introduces the characteristics of the zinc oxide (ZnO) inorganic film deposited by radio-frequency magnetron sputtering as an alternative alignment layer for liquid crystal display (LCD) applications. The crystalline structure related to the texture formation of ZnO (1013) was observed with a tilt angle of approximately 28.1 deg. to the ZnO (0001) plane, leading to a smooth surface and high-density structure. Ion beam (IB) bombardment at various incident angles was used to induce liquid crystal (LC) alignment and cause the measured pretilt angle on ZnO films to assume a triangular contour. The orientation order of liquid crystal molecules was due to the van der Waals force for the vertical alignment of LCs with selective breaking of O-Zn bonds by IB bombardment. The contact angle contour as a function of the IB incident angle resembled the behavior of the pretilt angle. The pretilt angle is controllable by adjusting the surface features on ZnO films with IB bombardment. The electro-optic characteristics of vertically aligned (VA)-LCD based on ZnO film were comparable to those of VA-LCD based on polyimide, showing good potential of ZnO film as a LC alignment layer.

  5. Metal catalyst for low-temperature growth of controlled zinc oxide nanowires on arbitrary substrates.

    PubMed

    Kim, Baek Hyun; Kwon, Jae W

    2014-03-14

    Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires.

  6. Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates

    PubMed Central

    Kim, Baek Hyun; Kwon, Jae W.

    2014-01-01

    Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

  7. A niobium oxide-tantalum oxide selector-memristor self-aligned nanostack

    NASA Astrophysics Data System (ADS)

    Diaz Leon, Juan J.; Norris, Kate J.; Yang, J. Joshua; Sevic, John F.; Kobayashi, Nobuhiko P.

    2017-03-01

    The integration of nonlinear current-voltage selectors and bi-stable memristors is a paramount step for reliable operation of crossbar arrays. In this paper, the self-aligned assembly of a single nanometer-scale device that contains both a selector and a memristor is presented. The two components (i.e., selector and memristor) are vertically assembled via a self-aligned fabrication process combined with electroforming. In designing the device, niobium oxide and tantalum oxide are chosen as materials for selector and memristor, respectively. The formation of niobium oxide is visualized by exploiting the self-limiting reaction between niobium and tantalum oxide; crystalline niobium (di)oxide forms at the interface between metallic niobium and tantalum oxide via electrothermal heating, resulting in a niobium oxide selector self-aligned to a tantalum oxide memristor. A steady-state finite element analysis is used to assess the electrothermal heating expected to occur in the device. Current-voltage measurements and structural/chemical analyses conducted for the virgin device, the electroforming process, and the functional selector-memristor device are presented. The demonstration of a self-aligned, monolithically integrated selector-memristor device would pave a practical pathway to various circuits based on memristors attainable at manufacturing scales.

  8. Ferromagnetism in p-Type Manganese-Doped Zinc Oxide Quantum Dots.

    PubMed

    May, Joseph W; McMorris, Ryan J; Li, Xiaosong

    2012-05-17

    The magnetic exchange interactions between paramagnetic Mn(2+) dopants in the presence of a N(2-) p-type defect in zinc oxide quantum dots are studied using density functional theory. Spin-dependent delocalization of the N(2-) 2p acceptor level among the nearest-neighbor Mn(2+) dopants is observed. The calculations show that parallel Mn(2+) spin alignment is favored upon the formation of a nitrogen-bridged Mn-Mn dimer. Although the effect is short-ranged, the observed magnitude of stabilization of the ferromagnetic alignment of nearest-neighbor Mn(2+) spins arises from p-d exchange and suggests p-type Mn(2+)-doped ZnO quantum dots as excellent candidates for exhibiting room-temperature ferromagnetism. Analytical expressions are derived and supported by density functional theory calculations that show that the N(2-) concentration has a stronger influence on the magnetic splitting compared with that of the Mn(2+) concentration.

  9. Some Aspects of Photoconductivity in Zinc Oxide

    DTIC Science & Technology

    1952-01-25

    the room to liquid air temperature range* >• ULfoattfy-* niWi H a .te^u*^•«-’""’^’’’^^ id Si £3* II» y^otog.ongujgjbl^’ty. of Zinc-Oxidei...varlpus insulators, evg.. HaCI, •Ü-. &i KOlj AgCI, and semiconductors, e,g«, CuO> Si * Ge, PbS, hus been furthered by the study of tto phoboconductive...dlseusoiuju uy § Rose20 on the effects of trapping and small capture cross section in hindering ’-n sß p;?-SB (, SI ’ recombination, and

  10. Growth mechanisms of zinc oxide and zinc sulfide films by mist chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Uno, Kazuyuki; Yamasaki, Yuichiro; Tanaka, Ichiro

    2017-01-01

    The growth mechanisms of zinc oxide and zinc sulfide films by mist chemical vapor deposition (mist-CVD) were experimentally investigated from the viewpoint of mist behaviors and chemical reactions. The proper growth model, either vaporization or the Leidenfrost model, was studied by supplying two kinds of mists with different kinds of sources, such as H2 16O and H2 18O for ZnO growth and ZnCl2 and thiourea for ZnS growth. Moreover, the origin of the oxygen atoms of ZnO was investigated using a quantitative analysis. The role of chloro complex of zinc in the growth of ZnS from aqueous solutions was also examined by systematic studies.

  11. Optical and field emission properties of Zinc Oxide nanostructures.

    PubMed

    Pan, Hui; Zhu, Yanwu; Ni, Zhenhua; Sun, Han; Poh, Cheekok; Lim, Sanhua; Sow, Chornghaur; Shen, Zexiang; Feng, Yuanping; Lin, Jianyi

    2005-10-01

    Zinc Oxide (ZnO) nano-pikes were produced by oxidative evaporation and condensation of Zn powders. The crystalline structure and optical properties of the ZnO nanostructures (ZnONs) greatly depend on the deposition position of the ZnONs. TEM and XRD indicated that the ZnONs close to the reactor center, ZnON-A, has better crystalline structure than the ZnONs away from the center, ZnON-B. ZnON-A showed the PL and Raman spectra characteristic of perfect ZnO crystals, whereas ZnON-B produced very strong green emission band at 500 nm in the photoluminescence (PL) spectrum and very strong Raman scattering peak at 560 cm(-1), both related to the oxygen deficiency due to insufficient oxidation of zinc vapor. ZnON-B exhibited better field emission properties with higher emission current density and lower turn-on field than ZnON-A.

  12. Zinc oxide's hierarchical nanostructure and its photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Kanjwal, Muzafar A.; Sheikh, Faheem A.; Barakat, Nasser A. M.; Li, Xiaoqiang; Kim, Hak Yong; Chronakis, Ioannis S.

    2012-02-01

    In this study, a new hierarchical nanostructure that consists of zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, zinc acetate dihydrate and poly(vinyl alcohol) was performed to produce polymeric nanofibers embedding solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 500 °C for 90 min produced pure ZnO nanofibers with rough surfaces. The rough surface strongly enhanced outgrowing of ZnO nanobranches when a specific hydrothermal technique was used. Methylene blue dihydrate was used to check the photocatalytic ability of the produced nanostructures. The results indicated that the hierarchical nanostructure had a better performance than the other form.

  13. Zinc oxide films prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Maciąg, Andrzej; Sagan, Piotr; Kuźma, Marian; Popovych, Volodymyr

    2016-12-01

    In this work we developed and tested spray pyrolysis system for layers deposition. In the system we have used ultrasonic apparatus (nebulizator) as a sprayer. A zinc nitrate aqueous solution has been used as a precursor solution. The idea of the method is the decomposition of nitrate on a hot substrate according to the reaction Zn(NO3)2 → ZnO +2 NO2 +1/2O2. The layers were grown on glass, (001)Si and KCl substrates at the temperatures 300 - 500°C. The thickness of the obtained layers was in the range 50 - 500 nm, depending on the growth time and rate. The influence of substrate temperature on the morphology of the layers has been studied by SEM method. The energy gap of the layers was found to be the range of 3.26-3.3 eV from their absorption spectra.

  14. A long life zinc oxide-titanium oxide sorbent for moving bed reactors

    SciTech Connect

    Copeland, R.; Cesario, M.; Dubovik, M.; Feinberg, D.; Windecker, B.; Yang, J.

    1996-12-31

    Coal Fired Gasifier Combined Cycles (GCCs) have both high efficiency and very low emissions. GCCs are in critical need of a method to remove the H{sub 2}S produced from the sulfur in the coal from the hot gases. There has been extensive research on hot gas clean-up systems, focused on the use of a zinc oxide based sorbent (e.g., zinc titanate). However, the previous sorbents show significant losses in sulfur capacity with cycling. TDA Research, Inc. recently increased the zinc oxide content and sulfur loadings while simultaneously improving the attrition resistance. The improved fabrication method produces long life, low cost sorbent containing zinc oxide. The authors are currently testing sorbents at conditions simulating a moving bed reactor for GCC [i.e., 20 atm, 482 C (900 F) to 538 C (1,000 F), and 1% H{sub 2}S].

  15. Thin film zinc oxide deposited by CVD and PVD

    NASA Astrophysics Data System (ADS)

    Hamelmann, Frank U.

    2016-10-01

    Zinc oxide is known as a mineral since 1810, but it came to scientific interest after its optoelectronic properties found to be tuneable by p-type doping. Since the late 1980’s the number of publications increased exponentially. All thin film deposition technologies, including sol-gel and spray pyrolysis, are able to produce ZnO films. However, for outstanding properties and specific doping, only chemical vapor deposition and physical vapor deposition have shown so far satisfying results in terms of high conductivity and high transparency. In this paper the different possibilities for doping will be discussed, some important applications of doped ZnO thin films will be presented. The deposition technologies used for industrial applications are shown in this paper. Especially sputtering of aluminium doped Zinc Oxide (ZnO:Al or AZO) and LPCVD of boron doped Zinc Oxide (ZnO:B or BZO) are used for the commercial production of transparent conductive oxide films on glass used for thin film photovoltaic cells. For this special application the typical process development for large area deposition is presented, with the important trade-off between optical properties (transparency and ability for light scattering) and electrical properties (conductivity). Also, the long term stability of doped ZnO films is important for applications, humidity in the ambient is often the reason for degradation of the films. The differences between the mentioned materials are presented.

  16. Recent progress in hydrothermal synthesis of zinc oxide nanomaterials.

    PubMed

    Djurisic, A B; Chen, X Y; Leung, Y H

    2012-06-01

    Hydrothermal synthesis is of considerable interest due to its low cost, simplicity and relatively low growth temperature (typically below 200 °C). Since the synthesis is performed in aqueous solutions (no organic solvents), it can also be safe and environmentally friendly (depending on precursor chemicals). Consequently, it has been a subject of intense research in recent years. In this article, we review recent progress in hydrothermal synthesis of zinc oxide nanomaterials, with focus on practical relevance for a variety of applications.

  17. Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress.

    PubMed

    Abrantes, Marta C; Kok, Jan; Silva Lopes, Maria de Fátima

    2014-12-01

    Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host.

  18. Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

    PubMed Central

    Pike, Sebastian D.; White, Edward R.; Shaffer, Milo S. P.; Williams, Charlotte K.

    2016-01-01

    The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2–4 nm) nanoparticles. PMID:27734828

  19. Radial growth of zinc oxide nanowire for piezoelectric nanogenerator application

    NASA Astrophysics Data System (ADS)

    Rasouli, Safa

    2017-04-01

    Nano- and micro-self-biased sensors employed environmental harvested energy, which are provided by different methods, such as piezoelectric. Piezoelectric materials are capable of producing electrical energy from environmental mechanical force. In this paper, a radial layer of well-arrayed hexagonal zinc oxide nanowires is grown on carbon fiber substrate using a two-step Chemical deposition method of metal salt growth. The resulted morphology is examined using Field Emission Scanning Electron Microscopy (FESEM) micrographs and X-ray Diffraction (XRD) pattern which indicates the quality and the crystallization order of the samples. In addition, composition of the material is studied using a Fourier Transform Infrared (FTIR) spectroscopy method. The results show that zinc oxide nanowires are well managed in vertical direction on the cylindrical carbon fibers. The hexagonal nanowires are grown with a length from 206 to 286 nm (Nanometer) and the diameter from 75 to 103 nm. The results of FTIR spectroscopy and XRD also illustrate the wurtzite structure of zinc oxide. The synthesized nanowires are then applied in a flexible capacitive piezoelectric nanogenerator consisting of a thin Ag layer as the upper contact and a carbon substrate as the back contact which are separated by a PMMA dielectric film. The output current and voltage are measured by applying a random pulse mechanical force on the upper contact. A maximum voltage and current of 14 mV (millivolt) and 20 nA (nanoampere) are generated at the output of nanogenerator, respectively.

  20. Nanocrystalline zinc oxide for the decontamination of sarin.

    PubMed

    Mahato, T H; Prasad, G K; Singh, Beer; Acharya, J; Srivastava, A R; Vijayaraghavan, R

    2009-06-15

    Nanocrystalline zinc oxide materials were prepared by sol-gel method and were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry, nitrogen adsorption and infrared spectroscopy techniques. The data confirmed the formation of zinc oxide materials of zincite phase with an average crystallite size of approximately 55 nm. Obtained material was tested as destructive adsorbent for the decontamination of sarin and the reaction was followed by GC-NPD and GC-MS techniques. The reaction products were characterized by GC-MS and the data explored the role of hydrolysis reaction in the detoxification of sarin. Sarin was hydrolyzed to form surface bound non-toxic phosphonate on the surface of nano-zinc oxide. The data also revealed the values of rate constant and half-life to be 4.12h(-1) and 0.16 h in the initial stages of the reaction and 0.361 h(-1) and 1.9h at the final stages of the reaction for the decontamination reaction on nanocrystalline ZnO.

  1. Pure spin current transport in gallium doped zinc oxide

    NASA Astrophysics Data System (ADS)

    Althammer, Matthias; Mukherjee, Joynarayan; Geprägs, Stephan; Goennenwein, Sebastian T. B.; Opel, Matthias; Ramachandra Rao, M. S.; Gross, Rudolf

    2017-01-01

    We study the flow of a pure spin current through zinc oxide by measuring the spin Hall magnetoresistance (SMR) in thin film trilayer samples consisting of bismuth-substituted yttrium iron garnet (Bi:YIG), gallium-doped zinc oxide (Ga:ZnO), and platinum. We investigate the dependence of the SMR magnitude on the thickness of the Ga:ZnO interlayer and compare to a Bi:YIG/Pt bilayer. We find that the SMR magnitude is reduced by almost one order of magnitude upon inserting a Ga:ZnO interlayer and continuously decreases with increasing interlayer thickness. Nevertheless, the SMR stays finite even for a 12 nm thick Ga:ZnO interlayer. These results show that a pure spin current indeed can propagate through a several nm-thick degenerately doped zinc oxide layer. We also observe differences in both the temperature and the field dependence of the SMR when comparing tri- and bilayers. Finally, we compare our data to the predictions of a model based on spin diffusion. This shows that interface resistances play a crucial role for the SMR magnitude in these trilayer structures.

  2. Excimer laser interaction with zinc oxide

    NASA Astrophysics Data System (ADS)

    Khan, Enamul Haque

    When single crystal ZnO is exposed to 193-nm laser photons in vacuum at fluences below 100 mJ/cm2, isolated Zn vacancies are produced due to the emission of energetic Zn+. The pair wise formation of Zn vacancies and Zn+ interstitials is attributed to the photochemical excitation of anti-bonding Zn-O bonds. Interstitial Zn + diffuses to the surface where it is loosely bound to the surface---often atop a photoionizable electron trap; adsorbed Zn+ is emitted when the underlying trap is photoionized. Isolated Zn vacancies also diffuse following the laser pulse. These electron traps can reduce the near-surface free carrier concentration by as much as a factor of five on irradiated samples. At fluences between 150 and 200 mJ/cm2, 193-nm irradiation produces sustained emission of ionic and neutral species. The near-surface region of the irradiated sample becomes increasingly metallic and zinc rich. At fluences in the 250--300 mJ/cm2 range, a slower component of the Zn+ emission appears which is attributed to the excitation of an auto-ionizing state at 12.77 eV. The same excitation also yields Zn atomic light emission, predominately due to transitions on the triplet manifold. Rydberg Zn* atoms in high-lying quantum states appear at a threshold fluence of about 350 mJ/cm2. At fluences greater than or equal to 2 J/cm2, atomic light emission due to optical breakdown is observed.

  3. Paradoxical zinc toxicity and oxidative stress in the mammary gland during marginal dietary zinc deficiency

    PubMed Central

    Bostanci, Zeynep; Mack, Ronald P.; Lee, Sooyeon; Soybel, David I.; Kelleher, Shannon L.

    2014-01-01

    Zinc (Zn) regulates numerous cellular functions. Zn deficiency is common in females; ~80% of women and 40% of adolescent girls consume inadequate Zn. Zn deficiency enhances oxidative stress, inflammation and DNA damage. Oxidative stress and inflammation is associated with breast disease. We hypothesized that Zn deficiency increases oxidative stress in the mammary gland, altering the microenvironment and architecture. Zn accumulated in the mammary glands of Zn deficient mice and this was associated with macrophage infiltration, enhanced oxidative stress and over-expression of estrogen receptor α. Ductal and stromal hypercellularity was associated with aberrant collagen deposition and disorganized e-cadherin. Importantly, these microenvironmental alterations were associated with substantial impairments in ductal expansion and mammary gland development. This is the first study to show that marginal Zn deficiency creates a toxic microenvironment in the mammary gland impairing breast development. These changes are consistent with hallmarks of potential increased risk for breast disease and cancer. PMID:25088245

  4. Zinc-oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasael

    2010-03-23

    Zinc oxide-based sorbents, and processes for preparing and using them are provided. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  5. Zinc oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2005-10-04

    Zinc oxide-based sorbents, and processes for preparing and using them are provided, wherein the sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents contain an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2 O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, containing a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  6. Organic molecules on metal and oxide semiconductor substrates: Adsorption behavior and electronic energy level alignment

    NASA Astrophysics Data System (ADS)

    Ruggieri, Charles M.

    Modern devices such as organic light emitting diodes use organic/oxide and organic/metal interfaces for crucial processes such as charge injection and charge transfer. Understanding fundamental physical processes occurring at these interfaces is essential to improving device performance. The ultimate goal of studying such interfaces is to form a predictive model of interfacial interactions, which has not yet been established. To this end, this thesis focuses on obtaining a better understanding of fundamental physical interactions governing molecular self-assembly and electronic energy level alignment at organic/metal and organic/oxide interfaces. This is accomplished by investigating both the molecular adsorption geometry using scanning tunneling microscopy, as well as the electronic structure at the interface using direct and inverse photoemission spectroscopy, and analyzing the results in the context of first principles electronic structure calculations. First, we study the adsorption geometry of zinc tetraphenylporphyrin (ZnTPP) molecules on three noble metal surfaces: Au(111), Ag(111), and Ag(100). These surfaces were chosen to systematically compare the molecular self-assembly and adsorption behavior on two metals of the same surface symmetry and two surface symmetries of one metal. From this investigation, we improve the understanding of self-assembly at organic/metal interfaces and the relative strengths of competing intermolecular and molecule-substrate interactions that influence molecular adsorption geometry. We then investigate the electronic structure of the ZnTPP/Au(111), Ag(111), and Ag(100) interfaces as examples of weakly-interacting systems. We compare these cases to ZnTPP on TiO2(110), a wide-bandgap oxide semiconductor, and explain the intermolecular and molecule-substrate interactions that determine the electronic energy level alignment at the interface. Finally we study tetracyanoquinodimethane (TCNQ), a strong electron acceptor, on TiO2

  7. Durable zinc oxide-containing sorbents for coal gas desulfurization

    DOEpatents

    Siriwardane, Ranjani V.

    1996-01-01

    Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

  8. MOCVD-growth of thin zinc oxide films from zinc acetylacetonate and air

    NASA Astrophysics Data System (ADS)

    Pflitsch, Christian; Nebatti, Abdelkader; Brors, Georg; Atakan, Burak

    2012-06-01

    The metalorganic chemical vapour deposition (MOCVD) of thin zinc oxide films on borosilicate glass and silicon substrates in a hot-wall CVD-reactor (HWR) was studied. Zinc acetylacetonate (Zn(acac)2) and air were used as precursors. The aim of this work was to optimize the deposition parameters, such as pressure and deposition temperature, with respect to the film quality, structure, and homogeneity. Most experiments were performed at atmospheric pressure; this approach avoids the usage of an expensive vacuum system. It turned out that polycrystalline zinc oxide is grown at deposition temperatures above 613 K. Above 823 K, they additionally are c-axis orientated. At atmospheric pressure and lower temperature (<773 K) the film deposition is homogeneously over the whole tube furnace while at higher temperature inhomogeneous film growth and particle formation are observed, indicating a shift of the growth mechanism to the diffusion controlled regime. Although the homogeneity is improved by using higher flow velocities at atmospheric pressure, particle growth cannot be suppressed. Only at reduced pressure, which was 200 mbar in the present case, the deposition at 823 K is kinetically controlled and without particle formation, resulting in the homogeneous growth of well adhering ZnO films with c-axis orientation.

  9. Rare earth doped zinc oxide varistors

    DOEpatents

    McMillan, A.D.; Modine, F.A.; Lauf, R.J.; Alim, M.A.; Mahan, G.D.; Bartkowiak, M.

    1998-12-29

    A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2--4.0% oxide of at least one rare earth element, 0.5--4.0% Co{sub 3}O{sub 4}, 0.05--0.4% K{sub 2}O, 0.05--0.2% Cr{sub 2}O{sub 3}, 0--0.2% CaO, 0.00005--0.01% Al{sub 2}O{sub 3}, 0--2% MnO, 0--0.05% MgO, 0--0.5% TiO{sub 3}, 0--0.2% SnO{sub 2}, 0--0.02% B{sub 2}O{sub 3}, balance ZnO. 4 figs.

  10. Rare earth doped zinc oxide varistors

    DOEpatents

    McMillan, April D.; Modine, Frank A.; Lauf, Robert J.; Alim, Mohammad A.; Mahan, Gerald D.; Bartkowiak, Miroslaw

    1998-01-01

    A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2-4.0% oxide of at least one rare earth element, 0.5-4.0% Co.sub.3 O.sub.4, 0.05-0.4% K.sub.2 O, 0.05-0.2% Cr.sub.2 O.sub.3, 0-0.2% CaO, 0.00005-0.01% Al.sub.2 O.sub.3, 0-2% MnO, 0-0.05% MgO, 0-0.5% TiO.sub.3, 0-0.2% SnO.sub.2, 0-0.02% B.sub.2 O.sub.3, balance ZnO.

  11. Seedless growth of zinc oxide flower-shaped structures on multilayer graphene by electrochemical deposition.

    PubMed

    Aziz, Nur Suhaili Abd; Nishiyama, Tomoya; Rusli, Nurul Izni; Mahmood, Mohamad Rusop; Yasui, Kanji; Hashim, Abdul Manaf

    2014-01-01

    A seedless growth of zinc oxide (ZnO) structures on multilayer (ML) graphene by electrochemical deposition without any pre-deposited ZnO seed layer or metal catalyst was studied. A high density of a mixture of vertically aligned/non-aligned ZnO rods and flower-shaped structures was obtained. ML graphene seems to generate the formation of flower-shaped structures due to the stacking boundaries. The nucleation of ZnO seems to be promoted at the stacking edges of ML graphene with the increase of applied current density, resulting in the formation of flower-shaped structures. The diameters of the rods/flower-shaped structures also increase with the applied current density. ZnO rods/flower-shaped structures with high aspect ratio over 5.0 and good crystallinity were obtained at the applied current densities of -0.5 and -1.0 mA/cm(2). The growth mechanism was proposed. The growth involves the formation of ZnO nucleation below 80°C and the enhancement of the growth of vertically non-aligned rods and flower-shaped structures at 80°C. Such ZnO/graphene hybrid structure provides several potential applications in sensing devices.

  12. Seedless growth of zinc oxide flower-shaped structures on multilayer graphene by electrochemical deposition

    PubMed Central

    2014-01-01

    A seedless growth of zinc oxide (ZnO) structures on multilayer (ML) graphene by electrochemical deposition without any pre-deposited ZnO seed layer or metal catalyst was studied. A high density of a mixture of vertically aligned/non-aligned ZnO rods and flower-shaped structures was obtained. ML graphene seems to generate the formation of flower-shaped structures due to the stacking boundaries. The nucleation of ZnO seems to be promoted at the stacking edges of ML graphene with the increase of applied current density, resulting in the formation of flower-shaped structures. The diameters of the rods/flower-shaped structures also increase with the applied current density. ZnO rods/flower-shaped structures with high aspect ratio over 5.0 and good crystallinity were obtained at the applied current densities of −0.5 and −1.0 mA/cm2. The growth mechanism was proposed. The growth involves the formation of ZnO nucleation below 80°C and the enhancement of the growth of vertically non-aligned rods and flower-shaped structures at 80°C. Such ZnO/graphene hybrid structure provides several potential applications in sensing devices. PMID:25024694

  13. Protein Biosensors Based on Polymer Nanowires, Carbon Nanotubes and Zinc Oxide Nanorods

    PubMed Central

    M., Anish Kumar; Jung, Soyoun; Ji, Taeksoo

    2011-01-01

    The development of biosensors using electrochemical methods is a promising application in the field of biotechnology. High sensitivity sensors for the bio-detection of proteins have been developed using several kinds of nanomaterials. The performance of the sensors depends on the type of nanostructures with which the biomaterials interact. One dimensional (1-D) structures such as nanowires, nanotubes and nanorods are proven to have high potential for bio-applications. In this paper we review these three different kinds of nanostructures that have attracted much attention at recent times with their great performance as biosensors. Materials such as polymers, carbon and zinc oxide have been widely used for the fabrication of nanostructures because of their enhanced performance in terms of sensitivity, biocompatibility, and ease of preparation. Thus we consider polymer nanowires, carbon nanotubes and zinc oxide nanorods for discussion in this paper. We consider three stages in the development of biosensors: (a) fabrication of biomaterials into nanostructures, (b) alignment of the nanostructures and (c) immobilization of proteins. Two different methods by which the biosensors can be developed at each stage for all the three nanostructures are examined. Finally, we conclude by mentioning some of the major challenges faced by many researchers who seek to fabricate biosensors for real time applications. PMID:22163892

  14. Protein biosensors based on polymer nanowires, carbon nanotubes and zinc oxide nanorods.

    PubMed

    Anish Kumar, M; Jung, Soyoun; Ji, Taeksoo

    2011-01-01

    The development of biosensors using electrochemical methods is a promising application in the field of biotechnology. High sensitivity sensors for the bio-detection of proteins have been developed using several kinds of nanomaterials. The performance of the sensors depends on the type of nanostructures with which the biomaterials interact. One dimensional (1-D) structures such as nanowires, nanotubes and nanorods are proven to have high potential for bio-applications. In this paper we review these three different kinds of nanostructures that have attracted much attention at recent times with their great performance as biosensors. Materials such as polymers, carbon and zinc oxide have been widely used for the fabrication of nanostructures because of their enhanced performance in terms of sensitivity, biocompatibility, and ease of preparation. Thus we consider polymer nanowires, carbon nanotubes and zinc oxide nanorods for discussion in this paper. We consider three stages in the development of biosensors: (a) fabrication of biomaterials into nanostructures, (b) alignment of the nanostructures and (c) immobilization of proteins. Two different methods by which the biosensors can be developed at each stage for all the three nanostructures are examined. Finally, we conclude by mentioning some of the major challenges faced by many researchers who seek to fabricate biosensors for real time applications.

  15. Silver/zinc oxide self-assembled nanostructured bolometer

    NASA Astrophysics Data System (ADS)

    Sanchez, John E.; González, Gabriel; Vera-Reveles, Gustavo; Velazquez-Salazar, J. Jesus; Bazan-Diaz, Lourdes; Gutiérrez-Hernández, José M.; José-Yacaman, Miguel; Ponce, Arturo; González, Francisco J.

    2017-03-01

    Temperature coefficient of resistance (TCR) is the main figure of merit for bolometric detectors. Reports show that zinc oxide can have TCR values higher than vanadium oxide (VOx) and amorphous silicon (a-Si), which are the most common materials used in bolometric applications, however its high resistivity makes it difficult to match it to read-out electronics. In this work, self-assembled nanostructures of Silver/Zinc oxide (Ag/ZnO) have been fabricated as well as their electrical and optical properties were measured as function of the Ag/ZnO concentration ratio. It was found that the nanostructures with the highest ZnO concentration exhibited a temperature coefficient of resistance as high as -11.8% K-1 near room temperature. Moreover, the TCR values and conductivity of the material can be tuned with the Ag/ZnO concentration ratio. This tuning flexibility allows this material to be better matched to read-out integrated circuits.

  16. The zinc ferrite obtained by oxidative precipitation method as a catalyst in n-butanol conversion

    SciTech Connect

    Klimkiewicz, Roman Wolska, Jolanta; Przepiera, Aleksander; Przepiera, Krystyna; Jablonski, Maciej; Lenart, Stanislaw

    2009-01-08

    This paper presents the results of catalytic properties of n-butanol conversion of the zinc ferrite obtained by oxidative precipitation method. The zinc ferrite showed good dehydrogenating activity but also catalyzed consecutive bimolecular condensation of emerged aldehyde particles into symmetrical ketone. The zinc-iron oxide of spinel structure was prepared from ferrous sulfate, which forms as a waste during the titanium dioxide production. The X-ray diffraction methods (XRD, XRF) were used in determining the structure and composition of obtained zinc ferrite, while thermogravimetry (TG-DTG), and differential thermal analysis (DTA) were used in the study of thermal transformations of zinc spinel in air.

  17. Developmental toxicity of intravenously injected zinc oxide nanoparticles in rats.

    PubMed

    Lee, Jinsoo; Yu, Wook-Joon; Song, Jeongah; Sung, Changhyun; Jeong, Eun Ju; Han, Ji-Seok; Kim, Pilje; Jo, Eunhye; Eom, Ikchun; Kim, Hyun-Mi; Kwon, Jung-Taek; Choi, Kyunghee; Choi, Jonghye; Kim, Heyjin; Lee, Handule; Park, Juyoung; Jin, Seon Mi; Park, Kwangsik

    2016-12-01

    Recent toxicity studies of zinc oxide nanoparticles by oral administration showed relatively low toxicity, which may be resulted from low bioavailability. So, the intrinsic toxicity of zinc oxide nanoparticles needs to be evaluated in the target organs by intravenous injection for full systemic concentration of the administered dosage. Although the exposure chance of injection route is low compared to oral and/or inhalation route, it is important to see the toxicity with different exposure routes to get better risk management tool. In this study, the effects of zinc oxide nanoparticles on dams and fetuses were investigated in rats after intravenous injection (5, 10, and 20 mg/kg) from gestation day 6 to 20. Two of 20 dams in the 20 mg/kg treatment group died during the treatment period. Hematological examination and serum biochemistry showed dose-dependent toxicity in treated dams. Histopathological analysis of treated dams revealed multifocal mixed cell infiltration and thrombosis in lung, tubular dilation in kidneys, and extramedullary hemopoiesis in liver. Total dead fetuses (post-implantation loss) were increased and the body weight of fetus was decreased in the 20 mg/kg treatment group. Statistical differences in corpora lutea, resorption, placental weight, morphological alterations including external, visceral and skeletal malformations were not observed in treated groups. Based on the data, lowest observed adverse effect level of injection route was suggested to be 5 mg/kg in dams and no observed adverse effect level was suggested to be 10 mg/kg in fetal developmental toxicity.

  18. Electron beam irradiation stiffens zinc tin oxide nanowires.

    PubMed

    Zang, Jianfeng; Bao, Lihong; Webb, Richard A; Li, Xiaodong

    2011-11-09

    We report a remarkable phenomenon that electron beam irradiation (EBI) significantly enhances the Young's modulus of zinc tin oxide (ZTO) nanowires (NWs), up to a 40% increase compared with the pristine NWs. In situ uniaxial buckling tests on individual NWs were conducted using a nanomanipulator inside a scanning electron microscope. We propose that EBI results in substantial atomic bond contraction in ZTO NWs, accounting for the observed mechanically stiffening. This argument is supported by our experimental results that EBI also reduces the electrical conductivity of ZTO NWs.

  19. Antireflective nanostructured zinc oxide arrays produced by pulsed electrodeposition

    SciTech Connect

    Klochko, N. P. Klepikova, K. S.; Khrypunov, G. S.; Volkova, N. D.; Kopach, V. R.; Lyubov, V. M.; Kirichenko, M. V.; Kopach, A. V.

    2015-02-15

    Conditions for the pulsed electrochemical deposition of nanostructured zinc oxide arrays with a certain morphology, crystal structure, and optical properties from aqueous electrolytes onto substrates of transparent electrically conducting tin dioxide and on single-crystal silicon wafers with built-in homojunctions are studied in order to develop antireflection coatings for solar cells. It is shown that it is possible to obtain single-layer planar antireflection coatings or arrays of nanorods of this material, both having the form of hexagonal prisms and exhibiting the moth-eye effect.

  20. Structural characterization of impurified zinc oxide thin films

    SciTech Connect

    Trinca, L. M.; Galca, A. C. Stancu, V. Chirila, C. Pintilie, L.

    2014-11-05

    Europium doped zinc oxide (Eu:ZnO) thin films have been obtained by pulsed laser deposition (PLD). 002 textured thin films were achieved on glass and silicon substrates, while hetero-epilayers and homo-epilayers have been attained on single crystal SrTiO{sub 3} and ZnO, respectively. X-ray Diffraction (XRD) was employed to characterize the Eu:ZnO thin films. Extended XRD studies confirmed the different thin film structural properties as function of chosen substrates.

  1. Behavior of zinc oxide surge arresters under pollution

    SciTech Connect

    Feser, F.; Kohler, W.; Qiu, D. ); Chrzan, K. )

    1991-04-01

    This paper presents results of pollution tests with AC voltages which were carried out with a multi-unit zinc oxide arrester. The interaction between the polluted porcelain housing and the inner varistor column due to capacitive coupling has been found to be responsible for the temperature rise of varistor elements. The different voltage distribution between inside and outside of the arrester also causes a high radial electric field which can lead to internal discharges if the radial insulation system is not properly designed. These internal discharges may damage varistor elements which are not adequately coated and may cause a total destruction of the arrester.

  2. A combined marginal deficiency of copper and zinc does not exacerbate oxidant stress asssociated with copper or zinc deficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both copper deficiency (Cu-def) and zinc deficiency (Zn-def) result in oxidative stress. Thus, an experiment was conducted to determine whether a marginal Zn-def amplified oxidative stress responses to a marginal Cu-def, or vice versa. Weanling male Sprague-Dawley rats were assigned to groups of 10 ...

  3. Electrochemical deposition of zinc oxide nanorods for hybrid solar cells

    NASA Astrophysics Data System (ADS)

    Torres Damasco Ty, Jennifer; Yanagi, Hisao

    2015-04-01

    Zinc oxide (ZnO) nanorod arrays for inorganic/organic hybrid solar cells were electrochemically deposited on indium tin oxide (ITO) substrates with a rotating disk electrode setup. The addition of a ZnO seed layer on the ITO prior to electrochemical deposition improved the morphology of the nanorods, resulting in nanorods with smaller and homogenous diameters as well as a higher degree of vertical orientation on to the substrate. The ZnO films deposited on the seeded ITO substrates had higher optical transmittance and lower concentration of defects. Chronoamperometric transient curves show that nucleation and coalescence occurred later for bare ITO substrates, indicating lower densities of initial nuclei, resulting in the growth of nanorods with larger diameters. The solar cell characteristics of the devices fabricated from the seeded ITO substrates were better. The seed layer also acts as a hole-blocking layer, preventing the direct contact between the hole-transporting polymer material and the ITO.

  4. Design and photocatalytic activity of nanosized zinc oxides

    NASA Astrophysics Data System (ADS)

    Gancheva, M.; Markova-Velichkova, M.; Atanasova, G.; Kovacheva, D.; Uzunov, I.; Cukeva, R.

    2016-04-01

    Zinc oxide particles with various morphologies were successfully prepared via three synthesis methods: precipitation; tribophysical treatment and sonochemistry. The as-synthesized samples were characterized by X-ray diffraction (XRD); infrared spectroscopy (IR); scanning electron microscope (SEM); BET specific surface area; electron-paramagnetic resonance (EPR), UV-Vis absorption/diffuse reflectance and X-ray photoelectron spectroscopy (XPS). Photocatalytic activities of the samples were evaluated by degradation of Malachite Green (MG) in an aqueous solution under UV and visible irradiation. The obtained ZnO powders possess crystallites size below 20 nm. The ZnO with spherical particles were obtained by precipitation method. The sonochemistry approach leads to preparation of ZnO with nanorod particles. The calculated band gaps of various ZnO powders belong to the range from 3.12 to 3.30 eV. The obtained polycrystalline zinc oxides exhibit good photocatalytic activity which is strongly influenced by the preparation conditions. The nanorod ZnO exhibits high photocatalytic activity under UV irradiation which is attributed to the morphology and the geometric surface of the particles. The ZnO obtained by precipitation has better photocatalytic efficiency under visible irradiation due to high B.E.T. specific surface area and the low level of band gap. Tribophysical treatment of a particle size-homogeneous system leads to deterioration of the photocatalytic activity of the material.

  5. Zinc oxide nanoparticles as novel alpha-amylase inhibitors

    NASA Astrophysics Data System (ADS)

    Dhobale, Sandip; Thite, Trupti; Laware, S. L.; Rode, C. V.; Koppikar, Soumya J.; Ghanekar, Ruchika-Kaul; Kale, S. N.

    2008-11-01

    Amylase inhibitors, also known as starch blockers, contain substances that prevent dietary starches from being absorbed by the body via inhibiting breakdown of complex sugars to simpler ones. In this sense, these materials are projected as having potential applications in diabetes control. In this context, we report on zinc oxide nanoparticles as possible alpha-amylase inhibitors. Zinc oxide nanoparticles have been synthesized using soft-chemistry approach and 1-thioglycerol was used as a surfactant to yield polycrystalline nanoparticles of size ˜18 nm, stabilized in wurtzite structure. Conjugation study and structural characterization have been done using x-ray diffraction technique, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and transmission electron microscopy. Cytotoxicity studies on human fibrosarcoma (HT-1080) and skin carcinoma (A-431) cell lines as well as mouse primary fibroblast cells demonstrate that up to a dose of 20 μg/ml, ZnO nanoparticles are nontoxic to the cells. We report for the first time the alpha-amylase inhibitory activity of ZnO nanoparticles wherein an optimum dose of 20 μg/ml was sufficient to exhibit 49% glucose inhibition at neutral pH and 35 °C temperature. This inhibitory activity was similar to that obtained with acarbose (a standard alpha-amylase inhibitor), thereby projecting ZnO nanoparticles as novel alpha-amylase inhibitors.

  6. Synthesis and characterization of Ar-annealed zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Kuthirummal, Narayanan; Smith, Gregory M.; Lopez, Leisha; Podila, Ramakrishna; Howell, Jason; Dun, Chaochao; Rao, Apparao M.

    2016-09-01

    Nanostructured zinc oxide samples were synthesized through CVD and annealed in argon. The samples were investigated using SEM, TEM, XRD, and UV/VIS/FTIR photoacoustic spectroscopy. The SEM/TEM images show relatively spherical particles that form elongated, connected domains post-anneal. XRD measurements indicate a typical wurtzite structure and reveal an increase in average grain size from 16.3 nm to 21.2 nm in Ar-annealed samples over pristine samples. Visible photoacoustic spectra reveal the contribution of defect levels on the absorption edge of the fundamental gap of zinc oxide. The steepness parameter of the absorption edge, which is inversely proportional to the width of the absorption edge, decreased from 0.1582 (pristine) to 0.1539 (annealed for 90 minutes) revealing increased density of defect states upon annealing. The FTIR photoacoustic spectra show an intense peak at 412 cm-1 and a shoulder at 504 cm-1 corresponding to the two transverse optical stretching modes of ZnO. These results may indicate a self-assembly mechanism upon anneal under Ar atmosphere leading to early-stage nanorod growth.

  7. Ferrate(VI) oxidation of zinc-cyanide complex.

    PubMed

    Yngard, Ria; Damrongsiri, Seelawut; Osathaphan, Khemarath; Sharma, Virender K

    2007-10-01

    Zinc-cyanide complexes are found in gold mining effluents and in metal finishing rinse water. The effect of Zn(II) on the oxidation of cyanide by ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) was thus investigated by studying the kinetics of the reaction of Fe(VI) with cyanide present in a potassium salt of a zinc cyanide complex (K(2)Zn(CN)(4)) and in a mixture of Zn(II) and cyanide solutions as a function of pH (9.0-11.0). The rate-law for the oxidation of Zn(CN)(4)(2-) by Fe(VI) was found to be -d[Fe(VI)]/dt=k[Fe(VI)][Zn(CN)(4)(2-)](0.5). The rate constant, k, decreased with an increase in pH. The effect of temperature (15-45 degrees C) on the oxidation was studied at pH 9.0, which gave an activation energy of 45.7+/-1.5kJmol(-1). The cyanide oxidation rate decreased in the presence of the Zn(II) ions. However, Zn(II) ions had no effect on the cyanide removal efficiency by Fe(VI) and the stoichiometry of Fe(VI) to cyanide was approximately 1:1; similar to the stoichiometry in absence of Zn(II) ions. The destruction of cyanide by Fe(VI) resulted in cyanate. The experiments on removal of cyanide from rinse water using Fe(VI) demonstrated complete conversion of cyanide to cyanate.

  8. Determining adaptive and adverse oxidative stress responses in human bronical epithelial cells exposed to zinc

    EPA Science Inventory

    Determining adaptive and adverse oxidative stress responses in human bronchial epithelial cells exposed to zincJenna M. Currier1,2, Wan-Yun Cheng1, Rory Conolly1, Brian N. Chorley1Zinc is a ubiquitous contaminant of ambient air that presents an oxidant challenge to the human lung...

  9. Inhibiting Metal Oxide Atomic Layer Deposition: Beyond Zinc Oxide.

    PubMed

    Sampson, Matthew D; Emery, Jonathan D; Pellin, Michael J; Martinson, Alex B F

    2017-04-05

    Atomic layer deposition (ALD) of several metal oxides is selectivity inhibited on alkanethiol self-assembled monolayers (SAMs) on Au, and the eventual nucleation mechanism is investigated. The inhibition ability of the SAM is significantly improved by the in situ H2-plasma pretreatment of the Au substrate prior to the gas-phase deposition of a long-chain alkanethiol, 1-dodecanethiol (DDT). This more rigorous surface preparation inhibits even aggressive oxide ALD precursors, including trimethylaluminum and water, for at least 20 cycles. We study the effect that the ALD precursor purge times, growth temperature, alkanethiol chain length, alkanethiol deposition time, and plasma treatment time have on Al2O3 ALD inhibition. This is the first example of Al2O3 ALD inhibition from a vapor-deposited SAM. The inhibitions of Al2O3, ZnO, and MnO ALD processes are compared, revealing the versatility of this selective surface treatment. Atomic force microscopy and grazing-incidence X-ray fluorescence further reveal insight into the mechanism by which the well-defined surface chemistry of ALD may eventually be circumvented to allow metal oxide nucleation and growth on SAM-modified surfaces.

  10. An assessment of zinc oxide nanosheets as a selective adsorbent for cadmium

    PubMed Central

    2013-01-01

    Zinc oxide nanosheet is assessed as a selective adsorbent for the detection and adsorption of cadmium using simple eco-friendly extraction method. Pure zinc oxide nanosheet powders were characterized using field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The zinc oxide nanosheets were applied to different metal ions, including Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). Zinc oxide nanosheets were found to be selective for cadmium among these metal ions when determined by inductively coupled plasma-optical emission spectrometry. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on zinc oxide nanosheets. PMID:24011201

  11. Influence of Camellia sinensis extract on Zinc Oxide nanoparticle green synthesis

    NASA Astrophysics Data System (ADS)

    Nava, O. J.; Luque, P. A.; Gómez-Gutiérrez, C. M.; Vilchis-Nestor, A. R.; Castro-Beltrán, A.; Mota-González, M. L.; Olivas, A.

    2017-04-01

    This work addresses low cost, non-toxic green synthesis of Zinc Oxide nanoparticles prepared using different amounts of Camellia sinensis extract. The Synthesized material was studied and characterized through Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), transmission electron microscopy (TEM). The Zinc Oxide nanoparticles presented the desired Znsbnd O bond at 618 cm-1, demonstrated growth in a purely hexagonal Wurtzite crystal structure, and, depending on the amount of extract used, they presented different size and shape homogeneity. The photocatalytic activity of the obtained Zinc Oxide nanoparticles was studied. The photocatalytic degradation studies were done at a 1:1 M ratio of methylene blue to Zinc Oxide nanoparticles under UV light. The obtained results presented a better degradation rate than commercially available Zinc Oxide nanoparticles.

  12. Resistance of extremely halophilic archaea to zinc and zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Salgaonkar, Bhakti B.; Das, Deepthi; Bragança, Judith Maria

    2016-02-01

    Industrialization as well as other anthropogenic activities have resulted in addition of high loads of metal and/or metal nanoparticles to the environment. In this study, the effect of one of the widely used heavy metal, zinc (Zn) and zinc oxide nanoparticles (ZnO NPs) on extremely halophilic archaea was evaluated. One representative member from four genera namely Halococcus, Haloferax, Halorubrum and Haloarcula of the family Halobacteriaceae was taken as the model organism. All the haloarchaeal genera investigated were resistant to both ZnCl2 and ZnO NPs at varying concentrations. Halococcus strain BK6 and Haloferax strain BBK2 showed the highest resistance in complex/minimal medium of up to 2.0/1.0 mM ZnCl2 and 2.0/1.0-0.5 mM ZnO NP. Accumulation of ZnCl2/ZnO NPs was seen as Haloferax strain BBK2 (287.2/549.6 mg g-1) > Halococcus strain BK6 (165.9/388.5 mg g-1) > Haloarcula strain BS2 (93.2/28.5 mg g-1) > Halorubrum strain BS17 (29.9/16.2 mg g-1). Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) analysis revealed that bulk ZnCl2 was sorbed at a higher concentration (21.77 %) on the cell surface of Haloferax strain BBK2 as compared to the ZnO NPs (14.89 %).

  13. Zinc oxide and related compounds: order within the disorder

    NASA Astrophysics Data System (ADS)

    Martins, R.; Pereira, Luisa; Barquinha, P.; Ferreira, I.; Prabakaran, R.; Goncalves, G.; Goncalves, A.; Fortunato, E.

    2009-02-01

    This paper discusses the effect of order and disorder on the electrical and optical performance of ionic oxide semiconductors based on zinc oxide. These materials are used as active thin films in electronic devices such as pn heterojunction solar cells and thin-film transistors. Considering the expected conduction mechanism in ordered and disordered semiconductors the role of the spherical symmetry of the s electron conduction bands will be analyzed and compared to covalent semiconductors. The obtained results show p-type c-Si/a-IZO/poly-ZGO solar cells exhibiting efficiencies above 14%, in device areas of about 2.34 cm2. Amorphous oxide TFTs based on the Ga-Zn-Sn-O system demonstrate superior performance than the polycrystalline TFTs based on ZnO, translated by ION/IOFF ratio exceeding 107, turn-on voltage below 1-2 V and saturation mobility above 25 cm2/Vs. Apart from that, preliminary data on p-type oxide TFT based on the Zn-Cu-O system will also be presented.

  14. Characterization of zinc oxide and zinc ferrite doped with Ti or Cu as sorbents for hot gas desulphurization

    NASA Astrophysics Data System (ADS)

    Pineda, Miguel; Fierro, JoséL. G.; Palacios, JoséM.; Cilleruelo, Cristina; García, Enrique; Ibarra, JoséV.

    1997-09-01

    Three series of samples based on zinc oxide and zinc ferrite doped with copper or titanium oxides have been prepared in order to improve their performance as regenerable sorbents for hot gas desulphurization. In each series the oxide concentration was varied over a broad range to enhance the formation of different chemical species. The stability against reducing agents and the performance of these sorbents were studied elsewhere. The characterization of fresh, sulphided and regenerated samples was undertaken using XRD, FT-Raman and XPS techniques. The addition of Ti increased the stability of ZnO against reducing agents such as H2, up to an atomic ratio Ti/Zn= 0.5 through the formation of Zn2TiO4. Furthermore, the Ti excess is segregated as TiO2. The addition of Cu to zinc ferrite did not affect the stability but improved the sorbent performance enhancing the ferrite formation and migrating to the sorbent surface during the calcination and regeneration steps. The addition of Ti to zinc ferrite prevented its decomposition into the two component oxides below 600°C stabilizing the structure through the inclusion of Ti in the ferrite lattice. In the sulphiding process Fe, Zn and Cu oxides were converted into the lowest oxidation state sulphides that facilitated the sorbent regeneration during the regeneration process.

  15. pH-dependent growth of zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Baruah, Sunandan; Dutta, Joydeep

    2009-04-01

    Here we study the effect of pH variation on the dimension and morphology of zinc oxide (ZnO) nanorods grown through hydrothermal process at temperatures less than 100 °C. ZnO nanorods were grown on pre-seeded glass substrates using zinc nitrate hexahydrate as the source of Zn ions and hexamethylenetetramine as the source of hydroxyl ions. The pH of the reaction bath was found to change gradually from 6.4 to 7.3 in 5 h during the growth process. The growth of the ZnO nanorods was observed to be faster, both laterally and longitudinally, when the growth solution was in basic conditions. However, flower petal like ZnO nanostructures were obtained when the growth process was initiated in basic condition (pH 8-12), indicating that initial acidic conditions were required to obtain nanorods with well-defined hexagonal facets. ZnO is known to erode in acidic condition and the final dimension of the nanorods is determined by a competition between crystal growth and etching. ZnO nanorods of different dimensions, both laterally (diameters ranging from 220 nm to 1 μm) and longitudinally (lengths ranging from 1 to 5.6 μm) were successfully synthesized using the same concentration of zinc nitrate and hexamine in the reaction bath and the same growth duration of 5 h simply through appropriate control of the pH of the reactant solution between 6 and 7.3.

  16. Oxidation kinetics of zinc sulfide: determination of intrinsic rate constant

    SciTech Connect

    Prabhu, G.M.

    1983-06-01

    An initial reaction rate study was done with the help of a thermogravimetric technique. Energy dispersive x-ray analyses on partially oxidized zinc sulfide pellets with a sintered porosity of 72.4% indicated flat sulfur intensity profiles within pellets reacted below 560/sup 0/C, which suggested a homogeneous reaction mechanism. Therefore, reaction temperatures below 600/sup 0/C were chosen for the reaction rate studies. Initial reaction rate studies on 72.4, 58.2, and 34.0% porous, cylindrical zinc sulfide pellets and the corresponding Arrhenius plot suggested chemical control in the temperature range from 480 to 565/sup 0/C. The corresponding intrinsic rate constant is correlated as k = 3.45 x 10/sup 17/ exp (- 86051/RT) cm/s. The variation in sulfur intensity within sintered pellets having a porosity of 72.4% that were reacted at temperatures above 560/sup 0/C indicated that the pore diffusion resistance gradually became comparable to the chemical reaction resistance leading to a mixed control mechanism above 570/sup 0/C. The critical temperature at which this shift occurred, increased with pellet porosity.

  17. Poly(vinylidene fluoride)/zinc oxide smart composite material

    NASA Astrophysics Data System (ADS)

    Öğüt, Erdem; Yördem, O. Sinan; Menceloğlu, Yusuf Z.; Papila, Melih

    2007-04-01

    This work aimed at fabrication and electromechanical characterization of a smart material system composed of electroactive polymer and ceramic materials. The idea of composite material system is on account of complementary characteristics of the polymer and ceramic for flexibility and piezoelectric activity. Our preliminary work included Polyvinylidene Fluoride (PVDF) as the flexible piezoelectric polymer, and Zinc Oxide (ZnO) as the piezoelectric ceramic brittle, but capable to respond strains without poling. Two alternative processes were investigated. The first process makes use of ZnO fibrous formation achieved by sintering PVA/zinc acetate precursor fibers via electrospinning. Highly brittle fibrous ZnO mat was dipped into a PVDF polymer solution and then pressed to form pellets. The second process employed commercial ZnO nanopowder material. The powder was mixed into a PVDF/acetone polymer solution, and the resultant paste was pressed to form pellets. The free standing composite pellets with electrodes on the top and bottom surfaces were then subjected to sinusoidal electric excitation and response was recorded using a fotonic sensor. An earlier work on electrospun PVDF fiber mats was also summarized here and the electromechanical characterization is reported.

  18. Nano-rods of zinc oxide in nano-graphene

    NASA Astrophysics Data System (ADS)

    Ortiz, Pedro; Chavira, Elizabeth; Monroy, Marel; Elizalde, José; Santiago, Patricia; Sato, Roberto; Tejeda, Adriana; González, Guillermina; Novelo, Omar; Flores, Carlos

    2014-03-01

    It's of great interest to study the devices based on nano-ZnO and graphene, for their electromagnetic and optical properties to increase the efficiency of solar cells. The graphene multilayers synthesis was done by mechanosynthesis, grinding in a mechanical agate mortar. The zinc oxide nano-rods were synthesized from zinc acetate dihydrate, Ace, (Sigma Aldrich) and ethylene diamine, En, (Sigma Aldrich) with a 1:2 ratio of reagents En/Ace. The ZnO nano-rods in nano-tubes graphene were obtained by mechanosynthesis. The X-ray powder diffraction, shows the shift of C with PDF 12-0212 and ZnO, Zincite PDF 36-1451, both with hexagonal unit cell. The grain size and morphology of graphene (multilayers and nano-tubes), ZnO nano-rods and ZnO-graphene mixture (multilayers, nano-tubes) were observed by scanning electron microscope. Transmission electron microscope, corroborates shown in SEM. Raman spectroscopy, shows the shift of multilayer graphene and the ZnO nano-rods. In photoluminescence measurements, observe the change in intensity in the band defects. Magnetic properties characterization was carried out by Vibrating Sample Magnetometry. We conclude that graphite multilayers dislocated by cutting efforts, forming graphene nano-tubes and encapsulated ZnO nano-rods within graphene.

  19. Zinc

    MedlinePlus

    ... pill" to help remove excess water from the body. Another effect of amiloride (Midamor) is that it can increase the amount of zinc in the body. Taking zinc supplements with amiloride (Midamor) might cause ...

  20. The zinc electrode - Its behaviour in the nickel oxide-zinc accumulator

    NASA Astrophysics Data System (ADS)

    Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling.

  1. Functionalization of textiles with silver and zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pulit-Prociak, Jolanta; Chwastowski, Jarosław; Kucharski, Arkadiusz; Banach, Marcin

    2016-11-01

    The paper presents a method for functionalization of textile materials using fabric dyes modified with silver or zinc oxide nanoparticles. Embedding of these nanoparticles into the structure of other materials makes that the final product is characterized by antimicrobial properties. Indigo and commercially available dye were involved in studies. It is worth to note that silver nanoparticles were obtained in-situ in the reaction of preparing indigo dye and in the process of preparing commercial dye baths. Such a method allows reducing technological steps. The modified dyes were used for dyeing of cotton fibers. The antimicrobial properties of final textile materials were studied. Saccharomyces cerevisiae strain was used in microbiological test. The results confirmed biocidal activity of prepared materials.

  2. Green Approach for Fabrication and Applications of Zinc Oxide Nanoparticles

    PubMed Central

    Smita, Kumari; Cumbal, Luis

    2014-01-01

    Zinc oxide nanoparticles (ZnO-NPs) are known to be one of the multifunctional inorganic compounds which are widely used in everyday applications. This study aims to fabricate ZnO-NPs using grapefruit (Citrus paradisi) peel extract with particle size ranging from 12 to 72 nm. Structural, morphological, and optical properties of the synthesized nanoparticles have been characterized by using UV-Vis spectrophotometer, TEM, DLS, and FTIR analysis. They show the significant photocatalytic degradation efficiency (>56%, 10 mg/L, 6 h) against methylene blue and antioxidant efficacy (≥80% for 1.2 mM) against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green ZnO-NPs could be used effectively in environmental safety applications and also can address future medical concerns. PMID:25374484

  3. Interpretation of optical conductivity of zinc oxide nanowires

    SciTech Connect

    Choudhary, K. K.; Kaurav, N.

    2015-07-31

    The frequency dependent optical response of Zinc Oxide (ZnO) nanowires is theoretically analyzed within the two component schemes: one is the motion of coherent Drude electrons within the ZnO nanowire and the other is incoherent motion of electrons from one nanowire to other. The model has only one free parameter, the relaxation rate. The frequency dependent relaxation rates are expressed in terms of memory functions. The coherent Drude carriers form a sharp peak at zero frequency and a long tail at higher frequencies, i.e. in the infrared region. However, the hopping of carriers from one nanowire to other (incoherent motion of electrons) yields a peak value in the optical conductivity around mid infrared region. It is found that both the Drude and hopping carriers will contribute to the optical process of conduction in ZnO nanowire.

  4. Gas sensing performance of nano zinc oxide sensors

    NASA Astrophysics Data System (ADS)

    Sharma, Shiva; Chauhan, Pratima

    2016-04-01

    We report nano Zinc Oxide (ZnO) synthesized by sol-gel method possessing the crystallite size which varies from 25.17 nm to 47.27 nm. The Scanning electron microscope (SEM) image confirms the uniform distribution of nanograins with high porosity. The Energy dispersion X-ray (EDAX) spectrum gives the atomic composition of Zn and O in ZnO powders and confirms the formation of nano ZnO particles. These factors reveals that Nano ZnO based gas sensors are highly sensitive to Ammonia gas (NH3) at room temperature, indicating the maximum response 86.8% at 800 ppm with fast response time and recovery time of 36 sec and 23 sec respectively.

  5. Phytofabrication of bioinspired zinc oxide nanocrystals for biomedical application.

    PubMed

    Velmurugan, Palanivel; Park, Jung-Hee; Lee, Sang-Myeong; Jang, Jum-Suk; Yi, Young-Joo; Han, Sang-Sub; Lee, Sang-Hyun; Cho, Kwang-Min; Cho, Min; Oh, Byung-Taek

    2016-09-01

    In the present study, we investigated a novel green route for synthesis of zinc oxide nanoparticles (ZnO NPs) using the extract of young cones of Pinus densiflora as a reducing agent. Standard characterization studies were carried out to confirm the obtained product using UV-Vis spectra, SEM-EDS, FTIR, and XRD. TEM images showed that various shapes of ZnO NPs were synthesized, including hexagonal (wurtzite), triangular, spherical, and oval-shaped particles, with average sizes between 10 and 100 nm. The synthesized ZnO NPs blended with the young pine cone extract have very good activity against bacterial and fungal pathogens, similar to that of commercial ZnO NPs.

  6. Stability of zinc oxide nanofluids prepared with aggregated nanocrystalline powders.

    PubMed

    Leonard, J P; Chung, S J; Nettleship, I; Soong, Y; Martello, D V; Chyu, M K

    2008-12-01

    Aqueous zinc oxide (ZnO) suspensions were prepared using a two-step preparation method in which an aggregated nanocrystalline ZnO powder was dispersed in water using a polyelectrolyte. The fluid showed anomalously high thermal conductivity when compared with the Maxwell and Hamilton-Crosser predictions. However, analysis of the particle size distribution showed that the fluid contained aggregated 20 nm crystallites of ZnO with a high volume fraction of particles larger than 100 nm. Sedimentation experiments revealed that particles settled out of the stationary fluid over times ranging from 0.1 hours to well over 10,000 hours. The size of the particles remaining in suspension agreed well with predictions made using Stoke's law, suggesting flocculation was not occurring in the fluids. Finally, a new concept of nanofluid stability is introduced based on the height of the fluid, sedimentation, Brownian motion and the kinetic energy of the particles.

  7. Gold coated zinc oxide nanonecklaces as a SERS substrate.

    PubMed

    He, Lili; Shi, Jian; Sun, Xin; Lin, Mengshi; Yu, Ping; Li, Hao

    2011-04-01

    Faceted zinc oxide nanonecklace (ZnO NN) arrays were grown on r-plane sapphires along one direction (ZnO [0001] II sapphire [10-11] and ZnO (-12-10) II sapphire (01-12)) using chemical vapor deposition. After coated with 45 nm gold films and annealed at 250 degrees C for 30 seconds, the coated ZnO NNs exhibit satisfactory and stable surface enhanced Raman scattering (SERS) effects when tested with melamine and other chemicals. The limit of detection of melamine is 10(-5) mol/L and the analytical enhancement factor is 10(4), which is competitive to a commercial substrate. This study indicates that gold coated ZnO NN substrates have a great potential as SERS-active substrates in rapid detection of trace amount food contaminants such as melamine and other chemicals.

  8. Zinc oxide tetrapods as efficient photocatalysts for organic pollutant degradation

    NASA Astrophysics Data System (ADS)

    Liu, Fangzhou; Leung, Yu Hang; Djurisić, Aleksandra B.; Liao, Changzhong; Shih, Kaimin

    2014-03-01

    Bisphenol A (BPA) and other organic pollutants from industrial wastewater have drawn increasing concern in the past decades regarding their environmental and biological risks, and hence developing strategies of effective degradation of BPA and other organic pollutants is imperative. Metal oxide nanostructures, in particular titanium oxide (TiO2) and zinc oxide (ZnO), have been demonstrated to exhibit efficient photodegradation of various common organic dyes. ZnO tetrapods are of special interest due to their low density of native defects which consequently lead to lower recombination losses and higher photocatalytic efficiency. Tetrapods can be obtained by relatively simple and low-cost vapor phase deposition in large quantity; the micron-scale size would also be advantageous for catalyst recovery. In this study, the photodegradation of BPA with ZnO tetrapods and TiO2 nanostructures under UV illumination were compared. The concentration of BPA dissolved in DI water was analyzed by high-performance liquid chromatography (HPLC) at specified time intervals. It was observed that the photocatalytic efficiency of ZnO tetrapods eventually surpassed Degussa P25 in free-standing form, and more than 80% of BPA was degraded after 60 min. Photodegradation of other organic dye pollutants by tetrapods and P25 were also examined. The superior photocatalytic efficiency of ZnO tetrapods for degradation of BPA and other organic dye pollutants and its correlation with the material properties were discussed.

  9. Fabrication and characterization of zinc oxide based rib waveguide

    NASA Astrophysics Data System (ADS)

    Gioffrè, M.; Gagliardi, M.; Casalino, M.; Coppola, G.; Iodice, M.; Della Corte, F.

    2007-02-01

    In this work we investigate the possibility to use Zinc Oxide (ZnO) thin films, deposited by RF magnetron sputtering, for the realization of integrated optical structures working at 1550 nm. Structural properties of sputtered zinc oxide thin films were studied by means of X-ray Diffraction (XRD) measurements, while optical properties were investigated by spectrophotometry and Spectroscopic Ellipsometry (SE). In particular, ellipsometric measurements allowed to determine the dispersion law of the ZnO complex refractive index (see manuscript) = n - jk through the multilayer modeling using Tauc-Lorentz (TL) dispersion model. We have found a preferential c-axis growth of ZnO films, with slightly variable deposition rates from 2.5 to 3.8 Å/s. Conversely, the refractive index exhibits, from UV to near IR, a considerable and almost linear variation when the oxygen flux value in the deposition chamber varies from 0 to 10 sccm. In order to realize a waveguide structure, a 3-μm-thick ZnO film was deposited onto silicon single crystal substrates, where a 0.5-μm-thick thermal SiO II buffer layer was previously realized, acting as lower cladding. Dry and wet chemical etching processes have been investigated to achieve controllable etching rate and step etching profile, with the aim to realize an optical rib waveguide. The etched surfaces were inspected using scanning electron microscopy (SEM) and optical microscopy. Moreover, we carried out the experimental measurements of the fringes pattern and Free Spectral Range (FSR) of an integrated Fabry- Perot etalon, obtained by cleaving of a single mode rib waveguide.

  10. Prenatal development toxicity study of zinc oxide nanoparticles in rats

    PubMed Central

    Hong, Jeong-Sup; Park, Myeong-Kyu; Kim, Min-Seok; Lim, Jeong-Hyeon; Park, Gil-Jong; Maeng, Eun-Ho; Shin, Jae-Ho; Kim, Meyoung-Kon; Jeong, Jayoung; Park, Jin-A; Kim, Jong-Choon; Shin, Ho-Chul

    2014-01-01

    This study investigated the potential adverse effects of zinc oxide nanoparticles ([ZnOSM20(+) NPs] zinc oxide nanoparticles, positively charged, 20 nm) on pregnant dams and embryo–fetal development after maternal exposure over the period of gestational days 5–19 with Sprague-Dawley rats. ZnOSM20(+) NPs were administered to pregnant rats by gavage at 0, 100, 200, and 400 mg/kg/day. All dams were subjected to a cesarean section on gestational day 20, and all of the fetuses were examined for external, visceral, and skeletal alterations. Toxicity in the dams manifested as significantly decreased body weight after administration of 400 mg/kg/day NPs; reduced food consumption after administration of 200 and 400 mg/kg/day NPs; and decreased liver weight and increased adrenal glands weight after administration of 400 mg/kg/day NPs. However, no treatment-related difference in: number of corpora lutea; number of implantation sites; implantation rate (%); resorption; dead fetuses; litter size; fetal deaths and placental weights; and sex ratio were observed between the groups. On the other hand, significant decreases between treatment groups and controls were seen for fetal weights after administration of 400 mg/kg/day NPs. Morphological examinations of the fetuses demonstrated significant differences in incidences of abnormalities in the group administered 400mg/kg/day. Meanwhile, no significant difference was found in the Zn content of fetal tissue between the control and high-dose groups. These results showed that oral doses for the study with 15-days repeated of ZnOSM20(+) NPs were maternotoxic in the 200 mg/kg/day group, and embryotoxic in the 400 mg/kg/day group. PMID:25565834

  11. Effect of morphology and solvent on two-photon absorption of nano zinc oxide

    SciTech Connect

    Kavitha, M.K.; Haripadmam, P.C.; Gopinath, Pramod; Krishnan, Bindu; John, Honey

    2013-05-15

    Highlights: ► ZnO nanospheres and triangular structures synthesis by novel precipitation technique. ► The effect of precursor concentration on the size and shape of nano ZnO. ► Open aperture Z-scan measurements of the ZnO nanoparticle dispersions. ► Nanospheres exhibit higher two photon absorption coefficient than triangular nanostructures. ► Nanospheres dispersed in water exhibit higher two photon absorption coefficient than its dispersion in 2-propanol. - Abstract: In this paper, we report the effect of morphology and solvent on the two-photon absorption of nano zinc oxide. Zinc oxide nanoparticles in two different morphologies like nanospheres and triangular nanostructures are synthesized by novel precipitation technique and their two-photon absorption coefficient is measured using open aperture Z-scan technique. Experimental results show that the zinc oxide nanospheres exhibit higher two-photon absorption coefficient than the zinc oxide triangular nanostructures. The zinc oxide nanospheres dispersed in water exhibit higher two-photon absorption coefficient than that of its dispersion in 2-propanol. The zinc oxide nanospheres dispersed in water shows a decrease in two-photon absorption coefficient with an increase in on-axis irradiance. The result confirms the dependence of shape and solvent on the two-photon absorption of nano zinc oxide.

  12. Conductivity study of nitrogen-doped calcium zinc oxide prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Ting; Lan, Wen-How; Huang, Kai-Feng; Lin, Jia-Ching; Chang, Kuo-Jen

    2016-01-01

    In this study, the spray pyrolysis method was used to prepare unintentionally doped and nitrogen-doped calcium zinc oxide films by using zinc acetate, calcium nitrate precursor, and ammonium acetate precursor. Morphological and structural analyses were conducted using scanning electron microscopy and X-ray diffraction. The results indicated that film grain size decreased as the nitrogen doping was increased. Both calcium oxide and zinc oxide structures were identified in the unintentionally doped calcium zinc oxide. When nitrogen doping was introduced, the film mainly exhibited a zinc oxide structure with preferred (002) and (101) orientations. The concentration and mobility were investigated using a Hall measurement system. P-type films with a mobility and concentration of 10.6 cm2 V-1 s-1 and 2.8×1017 cm-3, respectively, were obtained. Moreover, according to a temperature-dependent conductivity analysis, an acceptor state with activation energy 0.266 eV dominated the p-type conduction for the unintentionally doped calcium zinc oxide. By contrast, a grain boundary with a barrier height of 0.274-0.292 eV dominated the hole conduction for the nitrogen-doped calcium zinc oxide films.

  13. Texture and Topography Analysis of Doxycycline Hyclate Thermosensitive Systems Comprising Zinc Oxide

    PubMed Central

    Phaechamud, T.; Mahadlek, J.; Charoenteeraboon, J.

    2013-01-01

    To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol® F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol® F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol® F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol® F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol® F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol® F127. PMID:24302791

  14. Physiologically based pharmacokinetic modeling of zinc oxide nanoparticles and zinc nitrate in mice

    PubMed Central

    Chen, Wei-Yu; Cheng, Yi-Hsien; Hsieh, Nan-Hung; Wu, Bo-Chun; Chou, Wei-Chun; Ho, Chia-Chi; Chen, Jen-Kun; Liao, Chung-Min; Lin, Pinpin

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) have been widely used in consumer products, therapeutic agents, and drug delivery systems. However, the fate and behavior of ZnO NPs in living organisms are not well described. The purpose of this study was to develop a physiologically based pharmacokinetic model to describe the dynamic interactions of 65ZnO NPs in mice. We estimated key physicochemical parameters of partition coefficients and excretion or elimination rates, based on our previously published data quantifying the biodistributions of 10 nm and 71 nm 65ZnO NPs and zinc nitrate (65Zn(NO3)2) in various mice tissues. The time-dependent partition coefficients and excretion or elimination rates were used to construct our physiologically based pharmacokinetic model. In general, tissue partition coefficients of 65ZnO NPs were greater than those of 65Zn(NO3)2, particularly the lung partition coefficient of 10 nm 65ZnO NPs. Sensitivity analysis revealed that 71 nm 65ZnO NPs and 65Zn(NO3)2 were sensitive to excretion and elimination rates in the liver and gastrointestinal tract. Although the partition coefficient of the brain was relative low, it increased time-dependently for 65ZnO NPs and 65Zn(NO3)2. The simulation of 65Zn(NO3)2 was well fitted with the experimental data. However, replacing partition coefficients of 65ZnO NPs with those of 65Zn(NO3)2 after day 7 greatly improved the fitness of simulation, suggesting that ZnO NPs might decompose to zinc ion after day 7. In this study, we successfully established a potentially predictive dynamic model for slowly decomposed NPs. More caution is suggested for exposure to 65ZnO NPs <10 nm because those small 65ZnO NPs tend to accumulate in the body for a relatively longer time than 71 nm 65ZnO NPs and 65Zn(NO3)2 do. PMID:26491297

  15. Assessing the antimicrobial activity of zinc oxide thin films using disk diffusion and biofilm reactor

    NASA Astrophysics Data System (ADS)

    Gittard, Shaun D.; Perfect, John R.; Monteiro-Riviere, Nancy A.; Wei, Wei; Jin, Chunming; Narayan, Roger J.

    2009-03-01

    The electronic and chemical properties of semiconductor materials may be useful in preventing growth of microorganisms. In this article, in vitro methods for assessing microbial growth on semiconductor materials will be presented. The structural and biological properties of silicon wafers coated with zinc oxide thin films were evaluated using atomic force microscopy, X-ray photoelectron spectroscopy, and MTT viability assay. The antimicrobial properties of zinc oxide thin films were established using disk diffusion and CDC Biofilm Reactor studies. Our results suggest that zinc oxide and other semiconductor materials may play a leading role in providing antimicrobial functionality to the next-generation medical devices.

  16. Amorphous hafnium-indium-zinc oxide semiconductor thin film transistors

    NASA Astrophysics Data System (ADS)

    Kim, Chang-Jung; Kim, Sangwook; Lee, Je-Hun; Park, Jin-Seong; Kim, Sunil; Park, Jaechul; Lee, Eunha; Lee, Jaechul; Park, Youngsoo; Kim, Joo Han; Shin, Sung Tae; Chung, U.-In

    2009-12-01

    We developed amorphous hafnium-indium-zinc oxide (HIZO) thin films as oxide semiconductors and investigated the films electrically and physically. Adding of hafnium (Hf) element can suppress growing the columnar structure and drastically decrease the carrier concentration and hall mobility in HIZO films. The thin film transistors (TFTs) with amorphous HIZO active channel exhibit good electrical properties with field effect mobility of around 10 cm2/Vs, S of 0.23 V/decade, and high Ion/off ratio of over 108, enough to operate the next electronic devices. In particular, under bias-temperature stress test, the HIZO TFTs with 0.3 mol % (Hf content) showed only 0.46 V shift in threshold voltage, compared with 3.25 V shift in HIZO TFT (0.1 mol %). The Hf ions may play a key role to improve the instability of TFTs due to high oxygen bonding ability. Therefore, the amorphous HIZO semiconductor will be a prominent candidate as an operation device for large area electronic applications.

  17. CSA doped polypyrrole-zinc oxide thin film sensor

    NASA Astrophysics Data System (ADS)

    Chougule, M. A.; Jundale, D. M.; Raut, B. T.; Sen, Shashwati; Patil, V. B.

    2013-02-01

    The polypyrrole-zinc oxide (PPy-ZnO) hybrid sensor doped with different weight ratios of camphor sulphonic acid (CSA) were prepared by spin coating technique. These CSA doped PPy-ZnO hybrids were characterized by field emission scanning electron microscope (FESEM) and fourier transform infrared (FTIR) which proved the formation of polypyrrole, PPy-ZnO and the interaction between polypyrrole - ZnO (PPy-ZnO) hybrid with CSA doping. The gas sensing properties of the PPy-ZnO hybrid films doped with CSA have been studied for oxidizing (NO2) as well as reducing (H2S, NH3, CH4OH and CH3OH) gases at room temperature. We demonstrate that CSA doped PPy-ZnO hybrid films are highly selective to NO2 along with high-sensitivity at low concentration (80% to 100 ppm) and better stability, which suggested that the CSA doped PPy-ZnO hybrid films are potential candidate for NO2 detection at room temperature.

  18. Influence Of pH On The Transport Of Nanoscale Zinc Oxide In Saturated Porous Media

    EPA Science Inventory

    Widespread use of nanoscale zinc oxide (nZnO) in various fields causes subsurface environment contamination. Even though the transport of dissolved zinc ions in subsurface environments such as soils and sediments has been widely studied, the transport mechanism of nZnO in such e...

  19. Bioavailability of zinc oxide added to corn tortilla is similar to that of zinc sulfate and is not affected by simultaneous addition of iron

    PubMed Central

    Rosado, Jorge L.; Díaz, Margarita; Muñoz, Elsa; Westcott, Jamie L.; González, Karla E.; Krebs, Nancy F.; Caamaño, María C.; Hambidge, Michael

    2013-01-01

    Background Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron. Objective To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability. Methods A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method. Results The mean (± SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 ± 0.07, 0.36 ± 0.05, and 0.37 ± 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 ± 0.04, 0.33 ± 0.02, and 0.32 ± 0.05, respectively) and similar amounts of zinc absorbed (4.8 ± 0.7, 4.5 ± 0.3, and 4.8 ± 0.7 mg/day, respectively). Conclusions Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour. PMID:23424892

  20. Phosphate-enhanced cytotoxicity of zinc oxide nanoparticles and agglomerates.

    PubMed

    Everett, W Neil; Chern, Christina; Sun, Dazhi; McMahon, Rebecca E; Zhang, Xi; Chen, Wei-Jung A; Hahn, Mariah S; Sue, H-J

    2014-02-10

    Zinc oxide (ZnO) nanoparticles (NPs) have been found to readily react with phosphate ions to form zinc phosphate (Zn3(PO4)2) crystallites. Because phosphates are ubiquitous in physiological fluids as well as waste water streams, it is important to examine the potential effects that the formation of Zn3(PO4)2 crystallites may have on cell viability. Thus, the cytotoxic response of NIH/3T3 fibroblast cells was assessed following 24h of exposure to ZnO NPs suspended in media with and without the standard phosphate salt supplement. Both particle dosage and size have been shown to impact the cytotoxic effects of ZnO NPs, so doses ranging from 5 to 50 μg/mL were examined and agglomerate size effects were investigated by using the bioinert amphiphilic polymer polyvinylpyrrolidone (PVP) to generate water-soluble ZnO ranging from individually dispersed 4 nm NPs up to micron-sized agglomerates. Cell metabolic activity measures indicated that the presence of phosphate in the suspension media can led to significantly reduced cell viability at all agglomerate sizes and at lower ZnO dosages. In addition, a reduction in cell viability was observed when agglomerate size was decreased, but only in the phosphate-containing media. These metabolic activity results were reflected in separate measures of cell death via the lactate dehydrogenase assay. Our results suggest that, while higher doses of water-soluble ZnO NPs are cytotoxic, the presence of phosphates in the surrounding fluid can lead to significantly elevated levels of cell death at lower ZnO NP doses. Moreover, the extent of this death can potentially be modulated or offset by tuning the agglomerate size. These findings underscore the importance of understanding how nanoscale materials can interact with the components of surrounding fluids so that potential adverse effects of such interactions can be controlled.

  1. Hybridization of Zinc Oxide Tetrapods for Selective Gas Sensing Applications.

    PubMed

    Lupan, O; Postica, V; Gröttrup, J; Mishra, A K; de Leeuw, N H; Carreira, J F C; Rodrigues, J; Ben Sedrine, N; Correia, M R; Monteiro, T; Cretu, V; Tiginyanu, I; Smazna, D; Mishra, Y K; Adelung, R

    2017-02-01

    In this work, the exceptionally improved sensing capability of highly porous three-dimensional (3-D) hybrid ceramic networks toward reducing gases is demonstrated for the first time. The 3-D hybrid ceramic networks are based on doped metal oxides (MexOy and ZnxMe1-xOy, Me = Fe, Cu, Al) and alloyed zinc oxide tetrapods (ZnO-T) forming numerous junctions and heterojunctions. A change in morphology of the samples and formation of different complex microstructures is achieved by mixing the metallic (Fe, Cu, Al) microparticles with ZnO-T grown by the flame transport synthesis (FTS) in different weight ratios (ZnO-T:Me, e.g., 20:1) followed by subsequent thermal annealing in air. The gas sensing studies reveal the possibility to control and change/tune the selectivity of the materials, depending on the elemental content ratio and the type of added metal oxide in the 3-D ZnO-T hybrid networks. While pristine ZnO-T networks showed a good response to H2 gas, a change/tune in selectivity to ethanol vapor with a decrease in optimal operating temperature was observed in the networks hybridized with Fe-oxide and Cu-oxide. In the case of hybridization with ZnAl2O4, an improvement of H2 gas response (to ∼7.5) was reached at lower doping concentrations (20:1), whereas the increase in concentration of ZnAl2O4 (ZnO-T:Al, 10:1), the selectivity changes to methane CH4 gas (response is about 28). Selectivity tuning to different gases is attributed to the catalytic properties of the metal oxides after hybridization, while the gas sensitivity improvement is mainly associated with additional modulation of the electrical resistance by the built-in potential barriers between n-n and n-p heterojunctions, during adsorption and desorption of gaseous species. Density functional theory based calculations provided the mechanistic insights into the interactions between different hybrid networks and gas molecules to support the experimentally observed results. The studied networked materials and

  2. Zinc poisoning

    MedlinePlus

    ... other materials to make industrial items such as paint, dyes, and more. These combination substances can be ... Compounds used to make paint, rubber, dyes, wood preservatives, and ... Zinc chloride Zinc oxide (relatively nonharmful) Zinc ...

  3. Hydrothermal synthesis of zinc oxide nanoparticles using rice as soft biotemplate

    PubMed Central

    2013-01-01

    Background Rice as a renewable, abundant bio-resource with unique characteristics can be used as a bio-template to synthesize various functional nanomaterials. Therefore, the effect of uncooked rice flour as bio-template on physico-chemical properties, especially the morphology of zinc oxide nanostructures was investigated in this study. The ZnO particles were synthesized through hydrothermal-biotemplate method using zinc acetate-sodium hydroxide and uncooked rice flour at various ratios as precursors at 120°C for 18 hours. Results The results indicate that rice as a bio-template can be used to modify the shape and size of zinc oxide particles. Different morphologies, namely flake-, flower-, rose-, star- and rod-like structures were obtained with particle size at micro- and nanometer range. Pore size and texture of the resulting zinc oxide particles were found to be template-dependent and the resulting specific surface area enhanced compared to the zinc oxide synthesized without rice under the same conditions. However, optical property particularly the band gap energy is generally quite similar. Conclusion Pure zinc oxide crystals were successfully synthesized using rice flour as biotemplate at various ratios of zinc salt to rice. The size- and shape-controlled capability of rice to assemble the ZnO particles can be employed for further useful practical applications. PMID:23919386

  4. Formation of Flexible and Transparent Indium Gallium Zinc Oxide/Ag/Indium Gallium Zinc Oxide Multilayer Film

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ho; Kim, Da-Som; Kim, Sun-Kyung; Yoo, Young-Zo; Lee, Jeong Hwan; Kim, Sang-Woo; Seong, Tae-Yeon

    2016-08-01

    In this study, the electrical, optical, and bending characteristics of amorphous indium gallium zinc oxide (IGZO)/Ag/IGZO (39 nm/19 nm/39 nm) multilayer films deposited on polyethylene terephthalate (PET) substrate at room temperature were investigated and compared with those of Sn-doped indium oxide (ITO) (100 nm thick) films. At 500 nm the ITO film transmitted 91.3% and the IGZO/Ag/IGZO multilayer film transmitted 88.8%. The calculated transmittance spectrum of the multilayer film was similar to the experimental result. The ITO film and IGZO/Ag/IGZO multilayer film, respectively, showed carrier concentrations of 1.79 × 1020 and 7.68 × 1021 cm-3 and mobilities of 27.18 cm2/V s and 18.17 cm2/V s. The ITO film had a sheet resistance of 134.9 Ω/sq and the IGZO/Ag/IGZO multilayer film one of 5.09 Ω/sq. Haacke's figure of merit (FOM) was calculated to be 1.94 × 10-3 for the ITO film and 45.02 × 10-3 Ω-1 for the IGZO/Ag/IGZO multilayer film. The resistance change of 100 nm-thick ITO film was unstable even after five cycles, while that of the IGZO/Ag/IGZO film was constant up to 1000 cycles.

  5. Synthesis of carbon and zinc oxide nanotubes and their applications in electronic devices

    NASA Astrophysics Data System (ADS)

    Yang, Kaikun

    Nanostructured materials, including single and multiwalled carbon nanotubes (SWCNTs and MWCNTs), zinc oxide (ZnO) nanotubes (NTs) and graphene, have been successfully synthesized using chemical vapor deposition (CVD) or wet chemistry routines, and used to fabricate nanoelectronic and optoelectronic devices, including field effect transistors (FETs) and heterojunction solar cells. Both nanomaterials properties and devices performances have been characterized. Vertically aligned multiwalled carbon nanotubes (VACNTs) have been synthesized using both the pre-deposited iron films and the continuous supply of catalytic species via gas flow in pyrolytic decomposition of hydrocarbons by CVD. High quality VACNTs have been obtained after the optimization of synthesis parameters. Using metal nanoparticles as catalysts, centimeter-long SWCNTs have been synthesized on a silicon wafer with a thin thermal oxide layer. A series of FETs have been fabricated directly on a single SWCNT by inkjet printing of Pd nanoparticles to form both source and drain electrodes. The devices exhibit typical Schottky barrier p-type conductance characteristics. The line density and field mobility of charge carriers, as well as the effect of gate field modulation have been shown to strongly depend on thermal treatment of the SWCNT-FETs, implying the effect of carrier doping and interfacial reconstruction. ZnO NTs have been synthesized in an aqueous solution of zinc nitrate at 60ºC. A novel core-shell growth mechanism was hypothesized to explain the synthesis of ZnO NTs. The crystalline microstructures and optical properties of ZnO NTs upon thermal annealing in air at various temperatures have been examined. Ultraviolet-Visible (UV-Vis) absorption spectra reveal a slightly redshift of the direct band gap upon annealing. Solution structure of regioregular poly(3-hexylthiophene) (RR-P3HT) in toluene has been examined using optical spectroscopy in situ and atomic force microscopy upon casting films on a

  6. Ordered Nucleation Sites for the Growth of Zinc Oxide Nanofibers

    SciTech Connect

    Wang, J.; Ginley, D.S.; Shaheen, S.

    2006-01-01

    Organic photovoltaics (OPVs) offer a promising route to low cost photovoltaic (PV) technology that can be inexpensively manufactured on a large scale for use in power generation and commercial products. Solar power conversion efficiencies of laboratory scale OPV devices have recently reached ~5%; however, projected efficiencies of at least 10% will be required for commercialization. An analogous approach that has arisen recently that can potentially increase efficiencies employs metal oxide semiconductors as the electron acceptor, creating a hybrid organic-inorganic device. This approach offers the advantage that the conduction band of the oxide can be tuned in a systematic way through doping, thus potentially achieving higher photovoltages in the device. Additionally, nanostructures of these materials can be easily grown from precursor solutions, providing a technique to precisely control the nanoscale geometry. This work focuses on using ZnO, which is known to have high electron mobility (>100 cm2/Vs), as the electron acceptor. Nanofibers of ZnO can be grown from precursors such as zinc acetate or zinc nitrate to form arrays of nanofibers into which a conjugated polymer can be intercalated to form a composite PV device. The morphology of the nanofiber array is critical to the performance of the device, but current methods of nanofiber growth from a flat, polycrystalline nucleation layer allow for little morphological control. To overcome this limitation, we have created ordered arrays of ZnO nucleation sites with controllable size and spacing. Toluene solutions of diblock copolymer micelles with ZnCl2 incorporated into the micellar cores were spin-coated onto glass substrates and etched with an O2 plasma to yield hexagonally ordered arrays of ZnO nanoparticles that functioned as nucleation sites. Changing the concentration of ZnCl2 and the molecular weight and ratio of the diblock copolymer resulted in systematic variation in the size and spacing of the

  7. Transport of Zinc Oxide Nanoparticles in a Simulated Gastric Environment

    NASA Astrophysics Data System (ADS)

    Mayfield, Ryan T.

    Recent years have seen a growing interest in the use of many types of nano sized materials in the consumer sector. Potential uses include encapsulation of nutrients, providing antimicrobial activity, altering texture, or changing bioavailability of nutrients. Engineered nanoparticles (ENP) possess properties that are different than larger particles made of the same constituents. Properties such as solubility, aggregation state, and toxicity can all be changed as a function of size. The gastric environment is an important area for study of engineered nanoparticles because of the varied physical, chemical, and enzymatic processes that are prevalent there. These all have the potential to alter those properties of ENP that make them different from their bulk counterparts. The Human Gastric Simulator (HGS) is an advanced in vitro model that can be used to study many facets of digestion. The HGS consists of a plastic lining that acts as the stomach cavity with two sets of U-shaped arms on belts that provide the physical forces needed to replicate peristalsis. Altering the position of the arms or changing the speed of the motor which powers them allows one to tightly hone and replicate varied digestive conditions. Gastric juice, consisting of salts, enzymes, and acid levels which replicate physiological conditions, is introduced to the cavity at a controllable rate. The release of digested food from the lumen of simulated stomach is controlled by a peristaltic pump. The goal of the HGS is to accurately and repeatedly simulate human digestion. This study focused on introducing foods spiked with zinc oxide ENP and bulk zinc oxide into the HGS and then monitoring how the concentration of each changed at two locations in the HGS over a two hour period. The two locations chosen were the highest point in the lumen of the stomach, which represented the fundus, and a point just beyond the equivalent of the pylorus, which represented the antrum of the stomach. These points were

  8. Synthesis and characterization of nanostructured zinc oxide layers for sensor applications

    SciTech Connect

    Krasteva, L. K.; Dimitrov, D. Tz.; Papazova, K. I.; Nikolaev, N. K.; Peshkova, T. V.; Moshnikov, V. A.; Gracheva, I. E. Karpova, S. S.; Kaneva, N. V.

    2013-04-15

    Fractal structures and arrays of nanowires based on zinc oxide are fabricated by two different methods, sol-gel dip-coating and chemical bath deposition combined with sol-gel synthesis. The gas-sensitive properties of the structures are analyzed. It is found that the greatest sensitivity to reducing ethanol vapor is exhibited by the structure with a lower layer in the form of an array of zinc-oxide nanowires modified by four immersions in a copper nitrate solution.

  9. A study of mercuric oxide and zinc-air battery life in hearing aids.

    PubMed

    Sparkes, C; Lacey, N K

    1997-09-01

    The requirement to phase out mercuric oxide (mercury) batteries on environmental grounds has led to the widespread introduction of zinc-air technology. The possibility arises that high drain hearing aids may not be adequately catered for by zinc-air cells, leading to poor performance. This study investigated the hearing aid user's ability to perceive differences between zinc-air and mercury cells in normal everyday usage. The data was collected for 100 experienced hearing aid users in field trials. Users report 50 per cent greater life for zinc-air cells in high power aids and 28 per cent in low power aids. The average life of the zinc-air cells range from 15 days in high power to 34 days in low power aids. Users are able to perceive a difference in sound quality in favour of zinc-air cells for low and medium power aids. The hearing aid population is not disadvantaged by phasing out mercury cells.

  10. The role of intracellular zinc release in aging, oxidative stress, and Alzheimer’s disease

    PubMed Central

    McCord, Meghan C.; Aizenman, Elias

    2014-01-01

    Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury. PMID:24860495

  11. Antibacterial effect of zinc oxide nanoparticles combined with ultrasound

    NASA Astrophysics Data System (ADS)

    Seil, Justin T.; Webster, Thomas J.

    2012-12-01

    Using Staphylococcus aureus (S. aureus), the present study investigated the antibacterial effect of ZnO nanoparticles both in the absence and presence of ultrasound stimulation. While the antibacterial effect of control nanoparticle chemistries (Al2O3) alone was either weak or unobservable under the conditions tested, the antibacterial effect of ZnO alone was significant, providing over a four log reduction (equivalent to antibiotics) compared to no treatment after just 8 h. The antibacterial effect was enhanced as ZnO particle diameter decreased. Specifically, when testing the antibacterial effect against bacteria populations relevant to infection, a 500 μg ml-1 dose of zinc oxide nanoparticles with a diameter of 20 nm reduced S. aureus populations by four orders of magnitude after 8 and 24 h, compared to control groups with no nanoparticles. This was accomplished without the use of antibiotics, to which bacteria are developing a resistance anyway. The addition of ultrasound stimulation further reduced the number of viable colony-forming units present in a planktonic cell suspension by 76% compared to nanoparticles alone. Lastly, this study provided a mechanism for how ZnO nanoparticles in the presence of ultrasound decrease bacteria functions by demonstrating greater hydrogen peroxide generation by S. aureus compared to controls. These results indicated that small-diameter ZnO nanoparticles exhibited strong antibacterial properties that can be additionally enhanced in the presence of ultrasound and, thus, should be further studied for a wide range of medical device anti-infection applications.

  12. Study of phosphate removal from aqueous solution by zinc oxide.

    PubMed

    Luo, Zhen; Zhu, Suiyi; Liu, Zhongmou; Liu, Jiancong; Huo, Mingxin; Yang, Wu

    2015-09-01

    Zinc oxide (ZnO) was synthesized and used to investigate the mechanism of phosphate removal from aqueous solution. ZnO particles were characterized by X-ray diffraction, scanning electron microscope and Fourier transform infrared spectroscopy before and after adsorption. Batch experiments were carried out to investigate the kinetics, isotherms, effects of initial pH and co-existing anions. The adsorption process was rapid and equilibrium was almost reached within 150 min. The adsorption kinetics were described well by a pseudo-second-order equation, and the maximum phosphate adsorption capacity was 163.4 mg/g at 298 K and pH ∼6.2±0.1. Thermodynamic analysis indicated the phosphate adsorption onto ZnO was endothermic and spontaneous. The point of zero charge of ZnO was around 8.4 according to the pH-drift method. Phosphate adsorption capacity reduced with the increasing initial solution pH values. The ligand exchange and Lewis acid-base interaction dominated the adsorption process in the lower and the higher pH range, respectively. Nitrate, sulfate and chloride ions had a negligible effect on phosphate removal, while carbonate displayed significant inhibition behavior.

  13. Querectin Alleviates Zinc Oxide Nanoreprotoxicity in Male Albino Rats.

    PubMed

    Hussein, Mohamed M A; Ali, Haytham A; Saadeldin, Islam M; Ahmed, Mona M

    2016-10-01

    Zinc oxide nanopartciles (ZnONPs) involved in advanced technologies, and their wide-scale use in consumer market makes human beings more prone to the exposure to ZnONPs. The present study was undertaken to evaluate amelioration of ZnONP-induced toxicities with querectin in male albino rats. ZnONPs-treated rats showed a significant decrease in sperm cell count, sperm motility, live and normal sperms, as well as serum testosterone level. Severe histopathological damage with a significant increase in lipid peroxidation and a decrease in antioxidant enzymes activity and the GSH level were observed in the affected testis. Relative quantitative polymerase chain reaction results showed a significant decrease in antioxidant enzymes (superoxide dismutase and catalase) and a significant decrease in 3β-HSD, 17β-HSD, and Nr5A1 transcripts. Rats-administered querectin along with ZnONPs showed less toxic effects on all studied reproductive traits and mRNA transcripts. Our results suggest that querectin is beneficial for preventing or ameliorating ZnONP reproductive toxicities in males.

  14. Antibacterial effect of zinc oxide nanoparticles combined with ultrasound.

    PubMed

    Seil, Justin T; Webster, Thomas J

    2012-12-14

    Using Staphylococcus aureus (S. aureus), the present study investigated the antibacterial effect of ZnO nanoparticles both in the absence and presence of ultrasound stimulation. While the antibacterial effect of control nanoparticle chemistries (Al(2)O(3)) alone was either weak or unobservable under the conditions tested, the antibacterial effect of ZnO alone was significant, providing over a four log reduction (equivalent to antibiotics) compared to no treatment after just 8 h. The antibacterial effect was enhanced as ZnO particle diameter decreased. Specifically, when testing the antibacterial effect against bacteria populations relevant to infection, a 500 μg ml(-1) dose of zinc oxide nanoparticles with a diameter of 20 nm reduced S. aureus populations by four orders of magnitude after 8 and 24 h, compared to control groups with no nanoparticles. This was accomplished without the use of antibiotics, to which bacteria are developing a resistance anyway. The addition of ultrasound stimulation further reduced the number of viable colony-forming units present in a planktonic cell suspension by 76% compared to nanoparticles alone. Lastly, this study provided a mechanism for how ZnO nanoparticles in the presence of ultrasound decrease bacteria functions by demonstrating greater hydrogen peroxide generation by S. aureus compared to controls. These results indicated that small-diameter ZnO nanoparticles exhibited strong antibacterial properties that can be additionally enhanced in the presence of ultrasound and, thus, should be further studied for a wide range of medical device anti-infection applications.

  15. Zinc Oxide Coated Carbon Nanotubes for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Mohney, Austin; Stollberg, David

    2012-02-01

    Small scale electrical devices depend on bulky batteries that require recharging or replacement. In biomedical monitoring, where sensors could be implanted inside the body, maintenance of batteries presents a problem. It would be beneficial if small scale devices could generate their own power and alleviate their dependence on batteries. Piezoelectric nanogenerators have proven themselves as a viable means for ambient energy harvesting. Piezoelectric materials, such as zinc oxide (ZnO), produce a voltage difference when subjected to mechanical strain. Manipulation of this voltage can allow for the storage of energy to power small scale devices. The objective of this research is to manufacture a piezo-generator that can transduce mechanical vibrations into electrical energy. Carbon nanotubes, selected for their strong, flexible, and conductive properties, are used as a structural backbone for a ZnO piezoelectric coating and a Ag electrode coating. A Schottky diode interface is used to rectify the current output of the device. The devices yielded an average current output of .79 microAmps. SEM imagining was used to characterize the fabrication process. A Keithley 2700 digital multimeter was used to characterize the current output of the devices.

  16. The calculation of band gap energy in zinc oxide films

    NASA Astrophysics Data System (ADS)

    Arif, Ali; Belahssen, Okba; Gareh, Salim; Benramache, Said

    2015-01-01

    We investigated the optical properties of undoped zinc oxide thin films as the n-type semiconductor; the thin films were deposited at different precursor molarities by ultrasonic spray and spray pyrolysis techniques. The thin films were deposited at different substrate temperatures ranging between 200 and 500 °C. In this paper, we present a new approach to control the optical gap energy of ZnO thin films by concentration of the ZnO solution and substrate temperatures from experimental data, which were published in international journals. The model proposed to calculate the band gap energy with the Urbach energy was investigated. The relation between the experimental data and theoretical calculation suggests that the band gap energies are predominantly estimated by the Urbach energies, film transparency, and concentration of the ZnO solution and substrate temperatures. The measurements by these proposal models are in qualitative agreements with the experimental data; the correlation coefficient values were varied in the range 0.96-0.99999, indicating high quality representation of data based on Equation (2), so that the relative errors of all calculation are smaller than 4%. Thus, one can suppose that the undoped ZnO thin films are chemically purer and have many fewer defects and less disorder owing to an almost complete chemical decomposition and contained higher optical band gap energy.

  17. Sonochemical approach for rapid growth of zinc oxide nanowalls

    NASA Astrophysics Data System (ADS)

    Nayak, Avinash P.; Katzenmeyer, Aaron M.; Gosho, Yasuhiro; Tekin, Bayram; Islam, M. Saif

    2012-06-01

    The sonochemical process drives chemical reactions with sound fields by creating extraordinarily high density of energy, pressure and temperatures. The process resulted in a number of unexpected chemical species and thought-provoking results in the recent past. In this paper, we present a new sonochemical approach to synthesize ZnO (zinc oxide) nanowalls (NWalls) on aluminum and alumina coated substrates at room ambient conditions. We achieved highly dense and uniform ZnO NWalls in areas that are coated with Al or Al2O3 (alumina). The synthesis process was shown not to occur on Si, SiO2, Cr, or Ag surfaces. A series of experiments on understanding the growth kinetics offers detailed insight into the growth dynamics over time. Photoluminescence (PL) measurements, UV Vis spectroscopy, and SEM-EDS results confirm NWalls composed of crystalline ZnO that are formed via Al assisted growth induced by phase transformations under extraordinary pressure, temperature, and chemical growth kinetics. The chemical growth method as reported here, is applicable to arbitrary substrates coated with an Al thin film. We demonstrate the applications of the as-formed NWalls in UV photoconductors and gas sensors.

  18. Fungus mediated biosynthesis and characterization of zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Venkatesh, K. S.; Palani, N. S.; Krishnamoorthi, S. R.; Thirumal, V.; Ilangovan, R.

    2013-06-01

    Recently nanomaterials have been synthesized through biological approach due to its biocompatibility, inexpensive, eco friendly and it offers easiest experimental protocol and so on. ZnO can be potentially used in various applications. This present study reports the fungus mediated extra-cellular bio synthesis of ZnO nanorods using Fusarium Solani. The dried powder was calcined at 350°C for 1 hour in air. The thermal property of the as synthesized ZnO nanopowder was analyzed through Thermo gravimetric /Differential Thermo gravimetric (TGA / DTG) analysis. The structural and morphological properties of the calcined ZnO nanopowder were studied by XRD and SEM analysis respectively. X ray diffraction result revealed that a peak located at 2θ = 36.2° with (101) plane confirms the presence of Zinc oxide with Hexagonal crystal system. The morphology of the calcined ZnO powder was analyzed by Scanning Electron Microscopy and it clearly indicates the presence of ZnO nanorods. The diameter of the nanorods is in the range of 60 to 95 nm.

  19. Whispering Gallery Modes in Hexagonal Zinc Oxide Micro- and Nanocrystals

    NASA Astrophysics Data System (ADS)

    Nobis, Thomas; Kaidashev, Evgeni M.; Rahm, Andreas; Lorenz, Michael; Grundmann, Marius

    The resonator properties of zinc oxide (ZnO) micro- and nanocrystals grown by a novel high pressure pulsed laser deposition process have been investigated at room temperature by cathodoluminescence (CL), spatially resolved CL-imaging and polarization resolved micro-photoluminescence (μ-PL) within the visible spectral range. The spectra exhibit a series of comparatively sharp and almost equidistant resonance lines. Using a simple plane wave interference model and taking into account the spectral characteristic n(ω) of the refractive index of ZnO, we can unambiguously attribute those lines to whispering gallery modes (WGMs) of a two dimensional hexagonal resonator. The predicted resonator diameters agree well with the measured crystal sizes. Tapered, high aspect ratio ZnO nanoneedles furthermore allow systematic investigations of the WGMs as a function of cavity diameter D down to zero. Hence, the transition from a multi-mode to a single mode cavity is directly observed. μ-PL experiments demonstrate that the WGMs are mainly TM polarized.

  20. Immobilization of diastase α-amylase on nano zinc oxide.

    PubMed

    Antony, Navya; Balachandran, S; Mohanan, P V

    2016-11-15

    Diastase α-amylase extracted from malt, catalyses break down of starch into maltose. It is commonly used in food and fermentation industry. In the present study nano zinc oxide is used as support for this starch hydrolyzing enzyme. IR study revealed that the enzyme got adsorbed via electrostatic interaction with the functional groups on the support. The immobilized enzyme possessed a better heat-resistance than free enzyme. The kinetic parameters were determined using Lineweaver-Burk plot. The immobilized enzyme showed higher Km 2.08mg/ml than the free enzyme whose Km is 0.45±.05mg/ml. The Vmax of immobilized enzyme was about 2.92±.02mg/ml/min and that of free enzyme was 7.14±.02mg/ml/min, showing decrease in activity after immobilization. The immobilized enzyme showed 70% activity after 30days of storage while free enzyme lost its activity within 7days. About 80% of enzyme retained activity after 4 cycles of reuse.

  1. Zinc inhibits oxidative stress-induced iron signaling and apoptosis in Caco-2 cells.

    PubMed

    Kilari, Sreenivasulu; Pullakhandam, Raghu; Nair, K Madhavan

    2010-04-01

    Studies in humans and animals have suggested negative interactions of iron and zinc during their intestinal absorption. Further, zinc seems to prevent iron-induced oxidative damage in rats, which was hypothesized to be through the modulation of the intracellular iron signaling pathway. The aim of this study was, therefore, to understand the effects of zinc on oxidant-induced iron signaling and cell death in human enterocyte-like Caco-2 cells. We demonstrate that zinc decreases glucose/glucose oxidase (H(2)O(2)-generating system)-induced iron uptake and inhibits iron-regulatory protein 1 activation and divalent metal ion transporter 1 expression. There was also a concomitant decrease in oxidant-induced intracellular labile iron and restoration of ferritin and metallothionein expression. Further, zinc enhanced the Bcl-2/Bax ratio and reduced caspase-3 activity, leading to inhibition of apoptosis. Interestingly, bathophenanthroline disulfonic acid, an extracellular iron chelator, emulated the effects of zinc except for the reduced ferritin levels. These results suggest that zinc inhibits apoptosis by reducing oxidant-induced iron signaling in Caco-2 cells.

  2. Alterations of Bio-elements, Oxidative, and Inflammatory Status in the Zinc Deficiency Model in Rats.

    PubMed

    Doboszewska, Urszula; Szewczyk, Bernadeta; Sowa-Kućma, Magdalena; Noworyta-Sokołowska, Karolina; Misztak, Paulina; Gołębiowska, Joanna; Młyniec, Katarzyna; Ostachowicz, Beata; Krośniak, Mirosław; Wojtanowska-Krośniak, Agnieszka; Gołembiowska, Krystyna; Lankosz, Marek; Piekoszewski, Wojciech; Nowak, Gabriel

    2016-01-01

    Our previous study showed that dietary zinc restriction induces depression-like behavior with concomitant up-regulation of the N-methyl-D-aspartate receptor (NMDAR). Because metal ions, oxidative stress, and inflammation are involved in depression/NMDAR function, in the present study, bio-elements (zinc, copper, iron, magnesium, and calcium), oxidative (thiobarbituric acid-reactive substances; protein carbonyl content), and inflammatory (IL-1α, IL-1β) factors were measured in serum, hippocampus (Hp), and prefrontal cortex (PFC) of male Sprague-Dawley rats subjected to a zinc-adequate (ZnA) (50 mg Zn/kg) or a zinc-deficient (ZnD) (3 mg Zn/kg) diet for 4 or 6 weeks. Both periods of dietary zinc restriction reduced serum zinc and increased serum iron levels. At 4 weeks, lowered zinc level in the PFC and Hp as well as lowered iron level in the PFC of the ZnD rats was observed. At 6 weeks, however, iron level was increased in the PFC of these rats. Although at 6 weeks zinc level in the PFC did not differ between the ZnA and ZnD rats, extracellular zinc concentration after 100 mM KCl stimulation was reduced in the PFC of the ZnD rats and was accompanied by increased extracellular iron and glutamate levels (as measured by the in vivo microdialysis). The examined oxidative and inflammatory parameters were generally enhanced in the tissue of the ZnD animals. The obtained data suggest dynamic redistribution of bio-elements and enhancement of oxidative/inflammatory parameters after dietary zinc restriction, which may have a link with depression-like behavior/NMDAR function/neurodegeneration.

  3. Zinc oxide nanowire gamma ray detector with high spatiotemporal resolution

    NASA Astrophysics Data System (ADS)

    Mayo, Daniel C.; Nolen, J. Ryan; Cook, Andrew; Mu, Richard R.; Haglund, Richard F.

    2016-03-01

    Conventional scintillation detectors are typically single crystals of heavy-metal oxides or halides doped with rare-earth ions that record the recombination of electron-hole pairs by photon emission in the visible to ultraviolet. However, the light yields are typically low enough to require photomultiplier detection with the attendant instrumental complications. Here we report initial studies of gamma ray detection by zinc oxide (ZnO) nanowires, grown by vapor-solid deposition. The nanowires grow along the c-axis in a wurtzite structure; they are typically 80 nm in diameter and have lengths of 1- 2 μm. The nanowires are single crystals of high quality, with a photoluminescence (PL) yield from band-edge exciton emission in the ultraviolet that is typically one hundred times larger than the PL yield from defect centers in the visible. Nanowire ensembles were irradiated by 662 keV gamma rays from a Cs-137 source for periods of up to ten hours; gamma rays in this energy range interact by Compton scattering, which in ZnO creates F+ centers that relax to form singly-charged positive oxygen vacancies. Following irradiation, we fit the PL spectra of the visible emission with a sum of Gaussians at the energies of the known defects. We find highly efficient PL from the irradiated area, with a figure of merit approaching 106 photons/s/MeV of deposited energy. Over a period of days, the singly charged O+ vacancies relax to the more stable doubly charged O++ vacancies. However, the overall defect PL returns to pre-irradiation values after about a week, as the vacancies diffuse to the surface of these very thin nanowires, indicating that a self-healing process restores the nanowires to their original state.

  4. Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer

    SciTech Connect

    El-Atab, Nazek; Rizk, Ayman; Nayfeh, Ammar; Okyay, Ali K.

    2013-11-15

    A functional zinc-oxide based SONOS memory cell with ultra-thin chromium oxide trapping layer was fabricated. A 5 nm CrO{sub 2} layer is deposited between Atomic Layer Deposition (ALD) steps. A threshold voltage (V{sub t}) shift of 2.6V was achieved with a 10V programming voltage. Also for a 2V V{sub t} shift, the memory with CrO{sub 2} layer has a low programming voltage of 7.2V. Moreover, the deep trapping levels in CrO{sub 2} layer allows for additional scaling of the tunnel oxide due to an increase in the retention time. In addition, the structure was simulated using Physics Based TCAD. The results of the simulation fit very well with the experimental results providing an understanding of the charge trapping and tunneling physics.

  5. The influence of zinc chloride and zinc oxide nanoparticles on air-time survival in freshwater mussels.

    PubMed

    Gagné, François; Auclair, Joëlle; Peyrot, Caroline; Wilkinson, Kevin J

    2015-01-01

    The purpose of this study was to determine the cumulative effects of exposure to either dissolved zinc or nanozinc oxide (nanoZnO) and air-time survival in freshwater mussels. Mussels were exposed to each forms of zinc for 96h then placed in air to determine survival time. A sub-group of mussels before and after 7days of exposure to air were kept aside for the determination of the following biomarkers: arachidonate-dependent cyclooxygenase (COX) and peroxidase (inflammation and oxidative stress), lipid metabolism (total lipids, esterases activity, HO-glycerol, acetyl CoA and phospholipase A2) and lipid damage (lipid peroxidation [LPO]). The results showed that air-time survival was decreased from a mean value of 18.5days to a mean value of 12days in mussels exposed to 2.5mg/L of nanoZnO although it was not lethal based on shell opening at concentrations below 50mg/L after 96h. In mussels exposed to zinc only, the median lethal concentration was estimated at 16mg/L (10-25 95% CI). The air-time survival did not significantly change in mussels exposed to the same concentration of dissolved Zn. Significant weight losses were observed at 0.5mg/L of nanoZnO and at 2.5mg/L for dissolved zinc chloride, and were also significantly correlated with air-time survival (r=0.53; p<0.01). Air exposure significantly increased COX activity in control mussels and in mussels exposed to 0.5mg/L of nanoZnO and zinc chloride. The data also suggested fatty acid breakdown and β-oxidation. Mussels exposed to contaminants are more susceptible to prolonged exposure to air during low water levels.

  6. Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide nanochains for biomedical applications.

    PubMed

    Yuvakkumar, R; Suresh, J; Saravanakumar, B; Joseph Nathanael, A; Hong, Sun Ig; Rajendran, V

    2015-02-25

    A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ∼40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4 days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48 h incubation with 7 days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment.

  7. Dechlorination of Zinc Oxide Dust from Waelz Kiln by Microwave Roasting

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Zhang, Libo; Ma, Aiyuan; Peng, Jinhui; Li, Jing; Liu, Chenhui

    2015-05-01

    The new technology of dechlorination from zinc oxide dust by microwave roasting was investigated, combined with the advantages of microwave selective heating and based on a thermodynamic analysis of zinc and lead halides. The associated dechlorination reactions were discussed in details and the effect of all the influencing parameters such as roasting temperature, holding time, stirring speed and air flow were systematically investigated. Experimental results showed that zinc oxide dust dechlorination rate could reach over 95% and meet the requirements of wet smelting electrolysis, given an air flow of 300 L/h, a stirring speed of 60 r/min, a roasting temperature of 650 °C and a holding time of 30 min. Microwave roasting provided a new solution to the dechlorination from zinc oxide dust.

  8. Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell.

    PubMed

    Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

    2013-03-01

    Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition.

  9. Active sensing and damage detection using piezoelectric zinc oxide-based nanocomposites.

    PubMed

    Meyers, Frederick N; Loh, Kenneth J; Dodds, John S; Baltazar, Arturo

    2013-05-10

    This study investigated the design and performance of piezoelectric nanocomposite-based interdigitated transducers (IDTs) for active sensing and damage detection. First, thin films that are highly piezoelectric and mechanically flexible were designed by embedding zinc oxide (ZnO) nanoparticles in a poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) piezo-polymer matrix. Second, the suspended nanoparticle solutions were then spin coated onto patterned comb electrodes to fabricate the IDTs. The films were then poled to align their electric domains and to increase their permanent piezoelectricity. Upon IDT fabrication, its sensing and actuation of Lamb waves on an aluminum pipe was validated. These results were also compared to data obtained from commercial Macro Fiber Composite IDT transducers. In the last phase of this work, damage detection was demonstrated by mounting these nanocomposite sensors and actuators (using a pitch-catch setup) onto an aluminum pipe and plate. Damage was simulated by tightening a band clamp around the pipe and by drilling holes in the plate. A damage index calculation was used to compare results corresponding to different levels of damage applied to the plate (i.e., different drilled hole depths), and good correlation was observed. Thus, ZnO/PVDF-TrFE transducers were shown to have the potential for use as piezoelectric transducers for structural health monitoring and damage detection.

  10. Active sensing and damage detection using piezoelectric zinc oxide-based nanocomposites

    NASA Astrophysics Data System (ADS)

    Meyers, Frederick N.; Loh, Kenneth J.; Dodds, John S.; Baltazar, Arturo

    2013-05-01

    This study investigated the design and performance of piezoelectric nanocomposite-based interdigitated transducers (IDTs) for active sensing and damage detection. First, thin films that are highly piezoelectric and mechanically flexible were designed by embedding zinc oxide (ZnO) nanoparticles in a poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) piezo-polymer matrix. Second, the suspended nanoparticle solutions were then spin coated onto patterned comb electrodes to fabricate the IDTs. The films were then poled to align their electric domains and to increase their permanent piezoelectricity. Upon IDT fabrication, its sensing and actuation of Lamb waves on an aluminum pipe was validated. These results were also compared to data obtained from commercial Macro Fiber Composite IDT transducers. In the last phase of this work, damage detection was demonstrated by mounting these nanocomposite sensors and actuators (using a pitch-catch setup) onto an aluminum pipe and plate. Damage was simulated by tightening a band clamp around the pipe and by drilling holes in the plate. A damage index calculation was used to compare results corresponding to different levels of damage applied to the plate (i.e., different drilled hole depths), and good correlation was observed. Thus, ZnO/PVDF-TrFE transducers were shown to have the potential for use as piezoelectric transducers for structural health monitoring and damage detection.

  11. Importance of Plasmonic Heating on Visible Light Driven Photocatalysis of Gold Nanoparticle Decorated Zinc Oxide Nanorods

    PubMed Central

    Bora, Tanujjal; Zoepfl, David; Dutta, Joydeep

    2016-01-01

    Herein we explore the role of localized plasmonic heat generated by resonantly excited gold (Au) NPs on visible light driven photocatalysis process. Au NPs are deposited on the surface of vertically aligned zinc oxide nanorods (ZnO NRs). The localized heat generated by Au NPs under 532 nm continuous laser excitation (SPR excitation) was experimentally probed using Raman spectroscopy by following the phonon modes of ZnO. Under the resonant excitation the temperature at the surface of the Au-ZnO NRs reaches up to about 300 °C, resulting in almost 6 times higher apparent quantum yield (AQY) for photocatalytic degradation of methylene blue (MB) compared to the bare ZnO NRs. Under solar light irradiation the Au-ZnO NRs demonstrated visible light photocatalytic activity twice that of what was achieved with bare ZnO NRs, while significantly reduced the activation energy required for the photocatalytic reactions allowing the reactions to occur at a faster rate. PMID:27242172

  12. Fabrication of self-aligned, nanoscale, complex oxide varactors

    NASA Astrophysics Data System (ADS)

    Fu, Richard X.; Toonen, Ryan C.; Hirsch, Samuel G.; Ivill, Mathew P.; Cole, Melanie W.; Strawhecker, Kenneth E.

    2015-01-01

    Applications in ferroelectric random access memory and superparaelectric devices require the fabrication of ferroelectric capacitors at the nanoscale that exhibit extremely small leakage currents. To systematically study the material-size dependence of ferroelectric varactor performance, arrays of parallel-plate structures have been fabricated with nanoscale dielectric diameters. Electron beam lithography and inductively coupled plasma dry etching have been used to fabricate arrays of ferroelectric varactors using top electrodes as a self-aligned etch mask. Parallel-plate test structures using RF-sputtered Ba0.6Sr0.4TiO3 thin-films were used to optimize the fabrication process. Varactors with diameters down to 20 nm were successfully fabricated. Current-voltage (I-V) characteristics were measured to evaluate the significance of etch-damage and fabrication quality by ensuring low leakage currents through the structures.

  13. Nanomolar concentrations of zinc pyrithione increase cell susceptibility to oxidative stress induced by hydrogen peroxide in rat thymocytes.

    PubMed

    Oyama, Tomohiro M; Saito, Minoru; Yonezawa, Takayasu; Okano, Yoshiro; Oyama, Yasuo

    2012-06-01

    Zinc pyrithione is used as an antifouling agent. However, the environmental impacts of zinc pyrithione have recently been of concern. Zinc induces diverse actions during oxidative stress; therefore, we examined the effect of zinc pyrithione on rat thymocytes suffering from oxidative stress using appropriate fluorescent probes. The cytotoxicity of zinc pyrithione was not observed when the cells were incubated with 3 μM zinc pyrithione for 3 h. However, zinc pyrithione at nanomolar concentrations (10 nM or more) significantly increased the lethality of cells suffering from oxidative stress induced by 3 mM H(2)O(2). The application of zinc pyrithione alone at nanomolar concentrations increased intracellular Zn(2+) level and the cellular content of superoxide anions, and decreased the cellular content of nonprotein thiols. The simultaneous application of nanomolar zinc pyrithione and micromolar H(2)O(2) synergistically increased the intracellular Zn(2+) level. Therefore, zinc pyrithione at nanomolar concentrations may exert severe cytotoxic action on cells simultaneously exposed to chemicals that induce oxidative stress. If so, zinc pyrithione leaked from antifouling materials into surrounding environments would be a risk factor for aquatic ecosystems. Alternatively, zinc pyrithione under conditions of oxidative stress may become more potent antifouling ingredient.

  14. Chemical vapor deposition and characterization of zinc oxide thin films and nanostructures

    NASA Astrophysics Data System (ADS)

    Liu, Xiang

    2003-07-01

    Zinc oxide (ZnO) is a wide band gap semiconductor material. It is a promising candidate for short wavelength optoelectronic devices. Single crystalline and nanocrystalline ZnO thin films have been grown by organo-metallic chemical vapor depositions in a pulsed organo-metallic beam epitaxy (POMBE) system. The structural and morphological properties of ZnO films strongly depend on growth conditions. For epitaxially grown ZnO films on sapphire under optimal conditions, excellent crystallinity have been confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy (TEM) studies. Nanocrystalline films with columnar-shaped grains are grown with different grain sizes. With decreasing growth temperature, the morphology of POMBE grown ZnO goes through an transition from continuous thin film to nanorods. Well-aligned ZnO nanorods have been grown using two-step chemical vapor deposition methods. The growth mechanism is based on studies of ZnO nucleation. By controlling substrate temperature and oxygen concentration during the nucleation and growth steps, ZnO nanorods growth is achieved without any catalysts. High-resolution TEM studies show that ZnO nanorods are single crystals. Alignment of these nanorods depends on lattice match between ZnO and substrate. ZnO nanorods with different areal densities can be obtained by varying nucleation time. The photoluminescence (PL) spectra of nonorods have shown band edge emission at 380 nm with full width at half maximum (FWHM) of 106 meV which is comparable to films grown by molecular beam epitaxy (MBE). Green emissions are found to originate from oxygen vacancies and zinc interstitials; while orange-red emissions are attributed to oxygen interstitials. Optical properties of ZnO thin films and nanostructures are studied. Clear excitonic features observed in different optical measurements have proven good optical qualities of single crystal ZnO films. By alloying with magnesium, band gap of ZnO can be widened

  15. Antibacterial Activity of Dental Composites Containing Zinc Oxide Nanoparticles

    PubMed Central

    Sevinç, Berdan Aydin; Hanley, Luke

    2010-01-01

    The resin-based dental composites commonly used in restorations result in more plaque accumulation than other materials. Bacterial biofilm growth contributes to secondary caries and failure of resin-based dental composites. Methods to inhibit biofilm growth on dental composites have been sought for several decades. It is demonstrated here that zinc oxide nanoparticles (ZnO-NPs) blended at 10% (w/w) fraction into dental composites display antimicrobial activity and reduce growth of bacterial biofilms by roughly 80% for a single-species model dental biofilm. Antibacterial effectiveness of ZnO-NPs was assessed against Streptococcus sobrinus ATCC 27352 grown both planktonically and as biofilms on composites. Direct contact inhibition was observed by scanning electron microscopy and confocal laser scanning microscopy while biofilm formation was quantified by viable counts. An 80% reduction in bacterial counts was observed with 10% ZnO-NP-containing composites compared with their unmodified counterpart, indicating a statistically significant suppression of biofilm growth. Although, 20% of the bacterial population survived and could form a biofilm layer again, 10% ZnO-NP-containing composites maintained at least some inhibitory activity even after the third generation of biofilm growth. Microscopy demonstrated continuous biofilm formation for unmodified composites after one day growth, but only sparsely distributed biofilms formed on 10% ZnO-NP-containing composites. The minimum inhibitory concentration of ZnO-NPs suspended in S. sobrinus planktonic culture was 50 μg/ml. 10% ZnO-NP-containing composites qualitatively showed less biofilm after one day anaerobic growth of a three-species initial colonizer biofilm after when compared to unmodified composites, but did not significantly reduce growth after three days. PMID:20225252

  16. Decomposition of Organometal Halide Perovskite Films on Zinc Oxide Nanoparticles.

    PubMed

    Cheng, Yuanhang; Yang, Qing-Dan; Xiao, Jingyang; Xue, Qifan; Li, Ho-Wa; Guan, Zhiqiang; Yip, Hin-Lap; Tsang, Sai-Wing

    2015-09-16

    Solution processed zinc oxide (ZnO) nanoparticles (NPs) with excellent electron transport properties and a low-temperature process is a viable candidate to replace titanium dioxide (TiO2) as electron transport layer to develop high-efficiency perovskite solar cells on flexible substrates. However, the number of reported high-performance perovskite solar cells using ZnO-NPs is still limited. Here we report a detailed investigation on the chemistry and crystal growth of CH3NH3PbI3 perovskite on ZnO-NP thin films. We find that the perovskite films would severely decompose into PbI2 upon thermal annealing on the bare ZnO-NP surface. X-ray photoelectron spectroscopy (XPS) results show that the hydroxide groups on the ZnO-NP surface accelerate the decomposition of the perovskite films. To reduce the decomposition, we introduce a buffer layer in between the ZnO-NPs and perovskite layers. We find that a commonly used buffer layer with small molecule [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) can slow down but cannot completely avoid the decomposition. On the other hand, a polymeric buffer layer using poly(ethylenimine) (PEI) can effectively separate the ZnO-NPs and perovskite, which allows larger crystal formation with thermal annealing. The power conversion efficiencies of perovskite photovoltaic cells are significantly increased from 6.4% to 10.2% by replacing PC61BM with PEI as the buffer layer.

  17. Alveolar Epithelial Cell Injury Due to Zinc Oxide Nanoparticle Exposure

    PubMed Central

    Kim, Yong Ho; Fazlollahi, Farnoosh; Kennedy, Ian M.; Yacobi, Nazanin R.; Hamm-Alvarez, Sarah F.; Borok, Zea; Kim, Kwang-Jin; Crandall, Edward D.

    2010-01-01

    Rationale: Although inhalation of zinc oxide (ZnO) nanoparticles (NPs) is known to cause systemic disease (i.e., metal fume fever), little is known about mechanisms underlying injury to alveolar epithelium. Objectives: Investigate ZnO NP–induced injury to alveolar epithelium by exposing primary cultured rat alveolar epithelial cell monolayers (RAECMs) to ZnO NPs. Methods: RAECMs were exposed apically to ZnO NPs or, in some experiments, to culture fluid containing ZnCl2 or free Zn released from ZnO NPs. Transepithelial electrical resistance (RT) and equivalent short-circuit current (IEQ) were assessed as functions of concentration and time. Morphologic changes, lactate dehydrogenase release, cell membrane integrity, intracellular reactive oxygen species (ROS), and mitochondrial activity were measured. Measurements and Main Results: Apical exposure to 176 μg/ml ZnO NPs decreased RT and IEQ of RAECMs by 100% over 24 hours, whereas exposure to 11 μg/ml ZnO NPs had little effect. Changes in RT and IEQ caused by 176 μg/ml ZnO NPs were irreversible. ZnO NP effects on RT yielded half-maximal concentrations of approximately 20 μg/ml. Apical exposure for 24 hours to 176 μg/ml ZnO NPs induced decreases in mitochondrial activity and increases in lactate dehydrogenase release, permeability to fluorescein sulfonic acid, increased intracellular ROS, and translocation of ZnO NPs from apical to basolateral fluid (most likely across injured cells and/or damaged paracellular pathways). Conclusions: ZnO NPs cause severe injury to RAECMs in a dose- and time-dependent manner, mediated, at least in part, by free Zn released from ZnO NPs, mitochondrial dysfunction, and increased intracellular ROS. PMID:20639441

  18. Synaptic plasticity and oscillation at zinc tin oxide/silver oxide interfaces

    NASA Astrophysics Data System (ADS)

    Murdoch, Billy J.; McCulloch, Dougal G.; Partridge, James G.

    2017-02-01

    Short-term plasticity, long-term potentiation, and pulse interval dependent plasticity learning/memory functions have been observed in junctions between amorphous zinc-tin-oxide and silver-oxide. The same junctions exhibited current-controlled negative differential resistance and when connected in an appropriate circuit, they behaved as relaxation oscillators. These oscillators produced voltage pulses suitable for device programming. Transmission electron microscopy, energy dispersive X-ray spectroscopy, and electrical measurements suggest that the characteristics of these junctions arise from Ag+/O- electromigration across a highly resistive interface layer. With memory/learning functions and programming spikes provided in a single device structure, arrays of similar devices could be used to form transistor-free neuromorphic circuits.

  19. High performance organic photovoltaics with zinc oxide and graphene oxide buffer layers

    NASA Astrophysics Data System (ADS)

    Mohd Yusoff, Abd Rashid Bin; Kim, Hyeong Pil; Jang, Jin

    2014-01-01

    We report air stable inverted organic photovoltaics (OPVs) incorporating graphene oxide (GO) and solution processed zinc oxide (ZnO) as hole transport and electron transport layers, respectively. Both the hole transport layer and the electron transport layer (HTL and ETL) are of advantage in high transparency and environmental stability. The use of GO and ZnO in poly(2,7-carbazole) derivative (PCDTBT):fullerene derivative (PC70BM)-based inverted OPVs leads to an improved device stability and enhanced high open circuit voltage (Voc) of 0.81 V, a short-circuit current density (Jsc) of 14.10 mA cm-2, and a fill factor (FF) of 54.44 along with a power conversion efficiency of 6.20%.

  20. Curcumin Attenuates Hepatotoxicity Induced by Zinc Oxide Nanoparticles in Rats

    PubMed Central

    Khorsandi, Layasadat; Mansouri, Esrafil; Orazizadeh, Mahmoud; Jozi, Zahra

    2016-01-01

    Background: Zinc oxide nanoparticles (NZnO) are increasingly used in modern life. Most metal nanoparticles have adverse effects on the liver. Aims: To explore the protective action of curcumin (Cur) against hepatotoxicity induced by NZnO in rats. Study Design: Animal experimentation. Methods: Control group animals received normal saline, while the Cur group animals were treated with 200 mg/kg of Cur orally for 21 days. NZnO-intoxicated rats received 50 mg/kg of NZnO for 14 days by gavage method. In the NZnO+Cur group, rats were pretreated with Cur for 7 days before NZnO administration. Plasma activities of Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were measured as biomarkers of hepatotoxicity. Hepatic levels of malondialdehyde (MDA) and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured for detection of oxidative stress in liver tissue. Histological changes and apoptosis in liver tissue were studied by using Hematoxylin-eosin staining and the transferase dUTP nick end labeling (TUNEL) method. Results: NZnO induced a significant increase in plasma AST (2.8-fold), ALT (2.7-fold) and ALP (1.97-fold) activity in comparison to the control group (p<0.01). NZnO increased MDA content and reduced SOD and GPx activities. NZnO caused liver damage including centrilobular necrosis and microvesicular steatosis. The percentage of apoptosis in hepatocytes was increased in NZnO-treated rats (p<0.01). Pre-treatment of Cur significantly reduced lipid peroxidation (39%), increased SOD (156%) and GPx (26%) activities, and attenuated ALT (47%), AST (41%) and ALP (30%) activities. Pre-treatment with Cur also decreased the histology changes and apoptotic index of hepatocytes (p<0.05). Conclusion: These findings indicate that Cur effectively protects against NZnO-induced hepatotoxicity in rats. However, future studies are required to propose Cur as a potential protective agent against hepatotoxicity

  1. Feeding Low or Pharmacological Concentrations of Zinc Oxide Changes the Hepatic Proteome Profiles in Weaned Piglets

    PubMed Central

    Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

    2013-01-01

    Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs. PMID:24282572

  2. Effects of crocin and zinc chloride on blood levels of zinc and metabolic and oxidative parameters in streptozotocin-induced diabetic rats

    PubMed Central

    Asri-Rezaei, Siamak; Tamaddonfard, Esmaeal; Ghasemsoltani-Momtaz, Behnaz; Erfanparast, Amir; Gholamalipour, Sima

    2015-01-01

    Objectives: Crocin is one of constituents of saffron and has antioxidant property. Zinc chloride is one of the common compounds of zinc with antioxidant activity. The present study was aimed to investigate separate and combined treatment effects of crocin and zinc chloride on blood levels of zinc and metabolic and oxidative parameters in diabetic rats. Materials and Methods: Diabetes was induced by intraperitoneal (i.p.) injection of 50 mg/kg of streptozotocin (STZ) and was confirmed by blood glucose levels higher than 250 mg/dL. After confirmation of diabetes, injections (i.p.) of crocin and zinc chloride were performed for six weeks. At the end of the experiment, blood levels of zinc, glucose, insulin, malodialdehyde (MDA), and total antioxidant capacity (TAC) were measured. ‎ Results: Crocin (25 and 50 mg/kg) and zinc chloride (5 mg/kg) significantly recovered the decreased levels of zinc, insulin, and TAC and improved the increased levels of glucose and MDA in STZ-induced diabetic rats. In a combination treatment performed with an ineffective dose of crocin (12.5 mg/kg) and a low dose of zinc chloride (1.25 mg/kg), improving effects were observed on the above-mentioned biochemical parameters.‎ Conclusion: The results indicated that separate and combined treatments with crocin and zinc chloride produced improving effects on the blood levels of zinc, glucose, insulin, MDA and TAC in STZ-induced diabetic rats. PMID:26468459

  3. Comparison of Calcium Phosphate and Zinc Oxide Nanoparticles as Dermal Penetration Enhancers for Albumin

    PubMed Central

    Shokri, Narges; Javar, H. A.

    2015-01-01

    Dermal drug delivery is highly preferred by patients due to its several advantages. Protein therapeutics have attracted huge attention recently. Since dermal delivery of proteins encounter problems, in this investigation, zinc oxide nanoparticles and calcium phosphate nanoparticles were compared as enhancers for dermal permeation of albumin. Albumin was applied simultaneously with zinc oxide nanoparticles or calcium phosphate nanoparticles on pieces of mouse skin. Skin permeation of albumin over time was determined using a diffusion cell. Skin distribution of the nanoparticles and albumin over time was determined by optical and fluorescence microscopy. Zinc oxide nanoparticles and calcium phosphate nanoparticles acted as enhancers for skin permeation of albumin. Cumulative permeated albumin in presence of zinc oxide nanoparticles after 0, 0.5, 1, 1.5 and 2 h, were 0±0, 11.7±3.3, 21.1±3.5, 40.2±3.6 and 40.2±3.6 mg, respectively and in presence of calcium phosphate nanoparticles were 0±0, 20.9±7.4, 33.8±5.5, 33.8±3.7 and 33.8±3.7 mg, respectively. After 0.5 h, little amount of albumin was permeated in presence of every kind of the nanoparticles. After 0.5 or 1 h, the permeated albumin in presence of calcium phosphate nanoparticles was more than that in presence of zinc oxide nanoparticles and after 1.5 h the permeated albumin in presence of zinc oxide nanoparticles was more than that in presence of calcium phosphate nanoparticles. Images of skin distribution of the two nanoparticles over time, were somewhat different and distribution of albumin correlated with the distribution of the nanoparticles alone. The profiles of albumin permeation (in presence of each of the nanoparticles) versus time was delayed and linear for both nanoparticles while the slope for calcium phosphate nanoparticles was higher than zinc oxide nanoparticles. The enhancer effect of zinc oxide nanoparticles was stronger while the enhancer effect of calcium phosphate nanoparticles was

  4. Comparison of Calcium Phosphate and Zinc Oxide Nanoparticles as Dermal Penetration Enhancers for Albumin.

    PubMed

    Shokri, Narges; Javar, H A

    2015-01-01

    Dermal drug delivery is highly preferred by patients due to its several advantages. Protein therapeutics have attracted huge attention recently. Since dermal delivery of proteins encounter problems, in this investigation, zinc oxide nanoparticles and calcium phosphate nanoparticles were compared as enhancers for dermal permeation of albumin. Albumin was applied simultaneously with zinc oxide nanoparticles or calcium phosphate nanoparticles on pieces of mouse skin. Skin permeation of albumin over time was determined using a diffusion cell. Skin distribution of the nanoparticles and albumin over time was determined by optical and fluorescence microscopy. Zinc oxide nanoparticles and calcium phosphate nanoparticles acted as enhancers for skin permeation of albumin. Cumulative permeated albumin in presence of zinc oxide nanoparticles after 0, 0.5, 1, 1.5 and 2 h, were 0±0, 11.7±3.3, 21.1±3.5, 40.2±3.6 and 40.2±3.6 mg, respectively and in presence of calcium phosphate nanoparticles were 0±0, 20.9±7.4, 33.8±5.5, 33.8±3.7 and 33.8±3.7 mg, respectively. After 0.5 h, little amount of albumin was permeated in presence of every kind of the nanoparticles. After 0.5 or 1 h, the permeated albumin in presence of calcium phosphate nanoparticles was more than that in presence of zinc oxide nanoparticles and after 1.5 h the permeated albumin in presence of zinc oxide nanoparticles was more than that in presence of calcium phosphate nanoparticles. Images of skin distribution of the two nanoparticles over time, were somewhat different and distribution of albumin correlated with the distribution of the nanoparticles alone. The profiles of albumin permeation (in presence of each of the nanoparticles) versus time was delayed and linear for both nanoparticles while the slope for calcium phosphate nanoparticles was higher than zinc oxide nanoparticles. The enhancer effect of zinc oxide nanoparticles was stronger while the enhancer effect of calcium phosphate nanoparticles was

  5. The interaction of zinc oxide-based dental cements with aqueous solutions of potassium fluoride.

    PubMed

    Pawluk, K; Booth, S E; Coleman, N J; Nicholson, J W

    2008-09-01

    The ability of zinc oxide-based dental cements (zinc phosphate and zinc polycarboxylate) to take up fluoride from aqueous solution has been studied. Only zinc phosphate cement was found to take up any measurable fluoride after 5 h exposure to the solutions. The zinc oxide filler of the zinc phosphate also failed to take up fluoride from solution. The key interaction for this uptake was thus shown to involve the phosphate groups of the set cement. However, whether this took the form of phosphate/fluoride exchange, or the formation of oxyfluoro-phosphate groups was not clear. Fluoride uptake followed radicaltime kinetics for about 2 h in some cases, but was generally better modelled by the Elovich equation, dq(t)/dt = alpha exp(-betaq(t)). Values for alpha varied from 3.80 to 2.48 x 10(4), and for beta from 7.19 x 10(-3) to 0.1946, though only beta showed any sort of trend, becoming smaller with increasing fluoride concentration. Fluoride was released from the zinc phosphate cements in processes that were diffusion based up to M(t)/M(infinity) of about 0.4. No further release occurred when specimens were placed in fresh volumes of deionised water. Only a fraction of the fluoride taken up was re-released, demonstrating that most of the fluoride taken up becomes irreversibly bound within the cement.

  6. Solubility of nano-zinc oxide in environmentally and biologically important matrices

    PubMed Central

    Reed, Robert B.; Ladner, David A.; Higgins, Christopher P.; Westerhoff, Paul; Ranville, James F.

    2011-01-01

    Increasing manufacture and use of engineered nanoparticles (NPs) is leading to a greater probability for release of ENPs into the environment and exposure to organisms. In particular, zinc oxide (ZnO) is toxic, although it is unclear whether this toxicity is due to the zinc oxide nanoparticles (ZnO), dissolution to Zn2+, or some combination thereof. The goal of this study was to determine the relative solubilites of both commercially available and in-house synthesized ZnO in matrices used for environmental fate and transport or biological toxicity studies. Dissolution of ZnO was observed in nanopure water (7.18– 7.40 mg/L dissolved Zn, as measured by filtration) and Roswell Park Memorial Institute medium (RPMI-1640) (~5 mg/L), but much more dissolution was observed in Dulbecco’s Modified Eagle’s Medium (DMEM), where the dissolved Zn concentration exceeded 34 mg/L. Moderately hard water exhibited low zinc solubility, likely due to precipitation of a zinc carbonate solid phase. Precipitation of a zinc-containing solid phase in RPMI also appeared to limit zinc solubility. Equilibrium conditions with respect to ZnO solubility were not apparent in these matrices, even after more than 1,000 h of dissolution. These results suggest that solution chemistry exerts a strong influence on ZnO dissolution and can result in limits on zinc solubility due to precipitation of less soluble solid phases. PMID:21994124

  7. Anticancer activity of fungal L-asparaginase conjugated with zinc oxide nanoparticles.

    PubMed

    Baskar, G; Chandhuru, J; Sheraz Fahad, K; Praveen, A S; Chamundeeswari, M; Muthukumar, T

    2015-01-01

    Demand for developing novel delivery system for cancer treatment has increased due to the side effects present in intravenous injection of L-asparaginase. Nanoparticles are used for delivering the drugs to its destination in cancer cure. Nanobiocomposite of zinc oxide nanoparticles conjugated with L-asparaginase was produced by Aspergillus terreus and was confirmed using maximum UV-Vis absorption at 340 nm in the present work. The presence of functional groups like OH, C-H, -C=N and C=O on the surface of nanobiocomposite was found from Fourier transform infrared spectrum analysis. Size of the produced nanocomposite was found in the range of 28-63 nm using scanning electron microscope. The crystalline nature of the synthesized nanobiocomposites was confirmed by X-ray diffraction analysis. The presence of zinc oxide on synthesized nanobiocomposite was confirmed by energy dispersive spectrum analysis. The anti-cancerous nature of the synthesized zinc oxide conjugated L-asparaginase nanobiocomposite on MCF-7 cell line was studied using MTT assay. The viability of the MCF-7 cells was decreased to 35.02 % when it was treated with L-asparaginase conjugated zinc oxide nanobiocomposite. Hence it is proved that the synthesized nanobiocomposites of zinc oxide conjugated L-asparaginase has good anti-cancerous activity.

  8. Preliminary study on zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction

    NASA Astrophysics Data System (ADS)

    Wen, Yue-Hua; Cheng, Jie; Ning, Shang-Qi; Yang, Yu-Sheng

    A zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H 2-overpotential metal, cadmium, was used as the negative substrate electrode, the dendritic formation and hydrogen evolution are suppressed effectively, and granular zinc deposits become larger but relatively dense with the increase of charge time. The performance of batteries is favorable even if the charge time is as long as 5 h at the current density of 20 mA cm -2. Better discharge performance is achieved using a 'cavity-opening' configuration for the discharge cell rather than a 'gas-introducing' configuration. The highest energy efficiency is up to 59.2%. That is, the energy consumed by organic electro-synthesis can be recovered by 59.2%. Cyclic voltammograms show that the sintered nickel electrode exhibits a good electro-catalysis activity for the propanol oxidation. The increase of propanol concentration conduces to an enhancement in the organic electro-synthesis efficiency. The organic electro-synthesis current efficiency of 82% can be obtained.

  9. Planar-defect-rich zinc oxide nanoparticles assembled on carbon nanotube films as ultraviolet emitters and photocatalysts

    PubMed Central

    Zhu, Yunqing; Zhang, Xiaohua; Li, Ru; Li, Qingwen

    2014-01-01

    Structural defects in zinc oxide (ZnO) nanoparticles are complex and hard to be controlled during the synthesis, however, diversifying the chemical and physical performances. Here we report a rapid and low-temperature deposition method to fabricate planar-defect-rich ZnO nanoparticles on freestanding and aligned carbon nanotube films, different from common treatments which remove structural defects as many as possible. The defect energy states are very close to the valence band of ZnO and serve as recombination centers for a nearly monochromatic ultraviolet luminescence within a wavelength range of 373–376 nm. The absence of point defects, especially of oxygen vacancies whose energy level is <1 eV below the conduction band, allows photoinduced electrons and holes to take parts in possible photocatalytic reactions rather than to recombine at the shallow energy levels of planar defects. PMID:24740315

  10. Zinc (hydr)oxide/graphite oxide/AuNPs composites: role of surface features in H₂S reactive adsorption.

    PubMed

    Giannakoudakis, Dimitrios A; Bandosz, Teresa J

    2014-12-15

    Zinc hydroxide/graphite oxide/AuNPs composites with various levels of complexity were synthesized using an in situ precipitation method. Then they were used as H2S adsorbents in visible light. The materials' surfaces were characterized before and after H2S adsorption by various physical and chemical methods (XRD, FTIR, thermal analysis, potentiometric titration, adsorption of nitrogen and SEM/EDX). Significant differences in surface features and synergistic effects were found depending on the materials' composition. Addition of graphite oxide and the deposition of gold nanoparticles resulted in a marked increase in the adsorption capacity in comparison with that on the zinc hydroxide and zinc hydroxide/AuNP. Addition of AuNPs to zinc hydroxide led to a crystalline ZnO/AuNP composite while the zinc hydroxide/graphite oxide/AuNP composite was amorphous. The ZnOH/GO/AuNPs composite exhibited the greatest H2S adsorption capacity due to the increased number of OH terminal groups and the conductive properties of GO that facilitated the electron transfer and consequently the formation of superoxide ions promoting oxidation of hydrogen sulfide. AuNPs present in the composite increased the conductivity, helped with electron transfer to oxygen, and prevented the fast recombination of the electrons and holes.

  11. Facile synthesis of zinc hydroxide carbonate flowers on zinc oxide nanorods with attractive luminescent and optochemical performance

    NASA Astrophysics Data System (ADS)

    Mao, Jing; Li, Jia-Jun; Ling, Tao; Liu, Hui; Yang, Jing; Du, Xi-Wen

    2011-06-01

    A simple synthesis route was designed to fabricate a functional composite, zinc hydroxide carbonate (ZHC) flowers on zinc oxide (ZnO) nanorods. The hydrolysis of hexamethylenetetramine (HMT) can generate various species which are slowly released and gradually change reaction modes in a Zn(NO3)2/HMT solution. As a result, ZnO nanorods and ZHC flowers can be sequentially synthesized and connect very well under constant experimental conditions. The obtained composite has the advantages of both components and exhibits attractive properties. For instance, ZHC flowers on ZnO nanorods exhibit strong blue emission under the excitation of ultraviolet light, and dye-sensitized solar cells with the annealed composite as photoanode achieve much higher conversion efficiency than pure nanorod arrays.

  12. Zinc Oxide Nanoparticles Affect Biomass Accumulation and Photosynthesis in Arabidopsis

    PubMed Central

    Wang, Xiaoping; Yang, Xiyu; Chen, Siyu; Li, Qianqian; Wang, Wei; Hou, Chunjiang; Gao, Xiao; Wang, Li; Wang, Shucai

    2016-01-01

    Dramatic increase in the use of nanoparticles (NPs) in a variety of applications greatly increased the likelihood of the release of NPs into the environment. Zinc oxide nanoparticles (ZnO NPs) are among the most commonly used NPs, and it has been shown that ZnO NPs were harmful to several different plants. We report here the effects of ZnO NPs exposure on biomass accumulation and photosynthesis in Arabidopsis. We found that 200 and 300 mg/L ZnO NPs treatments reduced Arabidopsis growth by ∼20 and 80%, respectively, in comparison to the control. Pigments measurement showed that Chlorophyll a and b contents were reduced more than 50%, whereas carotenoid contents remain largely unaffected in 300 mg/L ZnO NPs treated Arabidopsis plants. Consistent with this, net rate of photosynthesis, leaf stomatal conductance, intercellular CO2 concentration and transpiration rate were all reduced more than 50% in 300 mg/L ZnO NPs treated plants. Quantitative RT-PCR results showed that expression levels of chlorophyll synthesis genes including CHLOROPHYLL A OXYGENASE (CAO), CHLOROPHYLL SYNTHASE (CHLG), COPPER RESPONSE DEFECT 1 (CRD1), MAGNESIUM-PROTOPORPHYRIN IX METHYLTRANSFERASE (CHLM) and MG-CHELATASE SUBUNIT D (CHLD), and photosystem structure gene PHOTOSYSTEM I SUBUNIT D-2 (PSAD2), PHOTOSYSTEM I SUBUNIT E-2 (PSAE2), PHOTOSYSTEM I SUBUNIT K (PSAK) and PHOTOSYSTEM I SUBUNIT K (PSAN) were reduced about five folds in 300 mg/L ZnO NPs treated plants. On the other hand, elevated expression, though to different degrees, of several carotenoids synthesis genes including GERANYLGERANYL PYROPHOSPHATE SYNTHASE 6 (GGPS6), PHYTOENE SYNTHASE (PSY) PHYTOENE DESATURASE (PDS), and ZETA-CAROTENE DESATURASE (ZDS) were observed in ZnO NPs treated plants. Taken together, these results suggest that toxicity effects of ZnO NPs observed in Arabidopsis was likely due to the inhibition of the expression of chlorophyll synthesis genes and photosystem structure genes, which results in the inhibition of

  13. Photocatalytic degradation of organochlorine compounds over titanium oxide and titanium oxide containing zinc oxide decatungstate and hydrogen peroxide

    SciTech Connect

    Sattari, D.

    1995-12-01

    Ten organochlorine solvents, commonly used in industry, which are di- tri- and tetra- chloro derivatives of methane, ethane and ethylene were photocatalytically degraded over titanium oxide and titanium oxide containing zinc oxide: decatungstate and hydrogen peroxide. The study has been carried out by determining the yield of organochlorine degradation at different irradiation time. It was found that for derivatives of the three compounds the degradation rates were in the order of di>tri>tetra and for those containing the same number of chlorine substituents the order was ethylene>ethane. During the degradation of each organochlorine solvent chloride was liberated. Stoichiometry for photocatalytic degradation of organochlorine solvents are C{sub x}H{sub y-z}Cl{sub z} + xO{sub 2}{yields}xCO{sub 2} + (y-z)H{sup +} + zCl{sup -}.

  14. Incomplete elimination of precursor ligands during atomic layer deposition of zinc-oxide, tin-oxide, and zinc-tin-oxide.

    PubMed

    Mackus, Adriaan J M; MacIsaac, Callisto; Kim, Woo-Hee; Bent, Stacey F

    2017-02-07

    For atomic layer deposition (ALD) of doped, ternary, and quaternary materials achieved by combining multiple binary ALD processes, it is often difficult to correlate the material properties and growth characteristics with the process parameters due to a limited understanding of the underlying surface chemistry. In this work, in situ Fourier transform infrared (FTIR) spectroscopy was employed during ALD of zinc-oxide, tin-oxide, and zinc-tin-oxide (ZTO) with the precursors diethylzinc (DEZ), tetrakis(dimethylamino)tin (TDMASn), and H2O. The main aim was to investigate the molecular basis for the nucleation delay during ALD of ZTO, observed when ZnO ALD is carried out after SnO2 ALD. Gas-phase FTIR spectroscopy showed that dimethylamine, the main reaction product of the SnO2 ALD process, is released not only during SnO2 ALD but also when depositing ZnO after SnO2, indicating incomplete removal of the ligands of the TDMASn precursor from the surface. Transmission FTIR spectroscopy performed during ALD on SiO2 powder revealed that a significant fraction of the ligands persist during both SnO2 and ZnO ALD. These observations provide experimental evidence for a recently proposed mechanism, based on theoretical calculations, suggesting that the elimination of precursor ligands is often not complete. In addition, it was found that the removal of precursor ligands by H2O exposure is even less effective when ZnO ALD is carried out after SnO2 ALD, which likely causes the nucleation delay in ZnO ALD during the deposition of ZTO. The underlying mechanisms and the consequences of the incomplete elimination of precursor ligands are discussed.

  15. Incomplete elimination of precursor ligands during atomic layer deposition of zinc-oxide, tin-oxide, and zinc-tin-oxide

    NASA Astrophysics Data System (ADS)

    Mackus, Adriaan J. M.; MacIsaac, Callisto; Kim, Woo-Hee; Bent, Stacey F.

    2017-02-01

    For atomic layer deposition (ALD) of doped, ternary, and quaternary materials achieved by combining multiple binary ALD processes, it is often difficult to correlate the material properties and growth characteristics with the process parameters due to a limited understanding of the underlying surface chemistry. In this work, in situ Fourier transform infrared (FTIR) spectroscopy was employed during ALD of zinc-oxide, tin-oxide, and zinc-tin-oxide (ZTO) with the precursors diethylzinc (DEZ), tetrakis(dimethylamino)tin (TDMASn), and H2O. The main aim was to investigate the molecular basis for the nucleation delay during ALD of ZTO, observed when ZnO ALD is carried out after SnO2 ALD. Gas-phase FTIR spectroscopy showed that dimethylamine, the main reaction product of the SnO2 ALD process, is released not only during SnO2 ALD but also when depositing ZnO after SnO2, indicating incomplete removal of the ligands of the TDMASn precursor from the surface. Transmission FTIR spectroscopy performed during ALD on SiO2 powder revealed that a significant fraction of the ligands persist during both SnO2 and ZnO ALD. These observations provide experimental evidence for a recently proposed mechanism, based on theoretical calculations, suggesting that the elimination of precursor ligands is often not complete. In addition, it was found that the removal of precursor ligands by H2O exposure is even less effective when ZnO ALD is carried out after SnO2 ALD, which likely causes the nucleation delay in ZnO ALD during the deposition of ZTO. The underlying mechanisms and the consequences of the incomplete elimination of precursor ligands are discussed.

  16. Synthesis and characterization of zinc oxide-neem oil-chitosan bionanocomposite for food packaging application.

    PubMed

    Sanuja, S; Agalya, A; Umapathy, M J

    2015-03-01

    Nano zinc oxide at different concentrations (0.1, 0.3 and 0.5%) and neem essential oil were incorporated into the chitosan polymer by solution cast method to enhance the properties of the bionanocomposite film. The functional groups, crystalline particle size, thermal stability and morphology were determined using FTIR, XRD, TGA and SEM, respectively. The results showed that 0.5% nano zinc oxide incorporated composite film have improved tensile strength, elongation, film thickness, film transparency and decreased water solubility, swelling and barrier properties due to the presence of neem oil and nano zinc oxide in the polymer matrix. Further antibacterial activity by well diffusion assay method was followed against Escherichia coli which were found to have good inhibition effect. In addition to this food quality application were carried against carrot and compared with the commercial film.

  17. BIOCHEMISTRY OF MOBILE ZINC AND NITRIC OXIDE REVEALED BY FLUORESCENT SENSORS

    PubMed Central

    Pluth, Michael D.; Tomat, Elisa; Lippard, Stephen J.

    2010-01-01

    Biologically mobile zinc and nitric oxide (NO) are two prominent examples of inorganic compounds involved in numerous signaling pathways in living systems. In the past decade, a synergy of regulation, signaling, and translocation of these two species has emerged in several areas of human physiology, providing additional incentive for developing adequate detection systems for Zn(II) ions and NO in biological specimens. Fluorescent probes for both of these bioinorganic analytes provide excellent tools for their detection, with high spatial and temporal resolution. We review the most widely used fluorescent sensors for biological zinc and nitric oxide, together with promising new developments and unmet needs of contemporary Zn(II) and NO biological imaging. The interplay between zinc and nitric oxide in the nervous, cardiovascular, and immune systems is highlighted to illustrate the contributions of selective fluorescent probes to the study of these two important bioinorganic analytes. PMID:21675918

  18. Biocidal effects of silver and zinc oxide nanoparticles on the bioluminescent bacteria

    NASA Astrophysics Data System (ADS)

    Taran, M. V.; Starodub, N. F.; Katsev, A. M.; Guidotti, M.; Khranovskyy, V. D.; Babanin, A. A.; Melnychuk, M. D.

    2013-11-01

    The effect of silver and zinc oxide nanoparticles in combination with alginate on bioluminescent Photobacterium leiognathi Sh1 bacteria was investigated. Silver nanoparticles were found to be more toxic than zinc oxide nanoparticles on bioluminescent bacteria. The nanoparticles and their ions released results in the same effect, however, it was absent in combination with alginate. The effective inhibiting concentration (EC50) for silver nanoparticles was found about 0.3 - 0.4 μg mL-1, which was up to two times larger then for zinc oxide nanoparticles. The absence of sodium chloride in the tested media prevented the formation of colloidal particles of larger size and the effective inhibition concentrations of metal derivatives were lower than in the presence of sodium chloride.

  19. The role of intracellular zinc in chromium(VI)-induced oxidative stress, DNA damage and apoptosis.

    PubMed

    Rudolf, Emil; Cervinka, Miroslav

    2006-09-25

    Several studies have demonstrated that zinc is required for the optimal functioning of the skin. Changes in intracellular zinc concentrations have been associated with both improved protection of skin cells against various noxious factors as well as with increased susceptibility to external stress. Still, little is known about the role of intracellular zinc in hexavalent chromium (Cr(VI))-induced skin injury. To address this question, the effects of zinc deficiency or supplementation on Cr(VI)-induced cytotoxicity, oxidative stress, DNA injury and cell death were investigated in human diploid dermal fibroblasts during 48 h. Zinc levels in fibroblasts were manipulated by pretreatment of cells with 100 microM ZnSO4 and 4 or 25 microM zinc chelator TPEN. Cr(VI) (50, 10 and 1 microM) was found to produce time- and dose-dependent cytotoxicity resulting in oxidative stress, suppression of antioxidant systems and activation of p53-dependent apoptosis which is reported for the first time in this model in relation to environmental Cr(VI). Increased intracellular zinc partially attenuated Cr(VI)-induced cytotoxicity, oxidative stress and apoptosis by enhancing cellular antioxidant systems while inhibiting Cr(VI)-dependent apoptosis by preventing the activation of caspase-3. Decreased intracellular zinc enhanced cytotoxic effects of all the tested Cr(VI) concentrations, leading to rapid loss of cell membrane integrity and nuclear dispersion--hallmarks of necrosis. These new findings suggest that Cr(VI) as a model environmental toxin may damage in deeper regions residing skin fibroblasts whose susceptibility to such toxin depends among others on their intracellular Zn levels. Further investigation of the impact of Zn status on skin cells as well as any other cell populations exposed to Cr(VI) or other heavy metals is warranted.

  20. EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES

    SciTech Connect

    Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.

    2010-01-21

    The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

  1. Teucrium polium L. extract adsorbed on zinc oxide nanoparticles as a fortified sunscreen

    PubMed Central

    Ansari, Mehdi; Sharififar, Fariba; Kazemipour, Maryam; Sarhadinejad, Zarrin; Mahdavi, Hamid

    2013-01-01

    Introduction: Zinc oxide nanoparticles (ZnOn) have been used as carriers and sun-protecting agents for Teucrium polium L. extract to enhance sun protection. ZnOn was synthesized by hydrolyzing zinc acetate using sodium hydroxide with mean particle diameter less than 500 nm. Materials and Methods: Top flowerings of T. polium L. were extracted by percolation method with petroleum ether, chloroform, and 80% methanol consecutively. Methanolic extract was lyophilized and used as a flavonoid-rich fraction. Sunscreen was prepared by the reconstitution of 0.5 g of the lyophilized extract in water and mixing with 0.5 to 2 g zinc-oxide (ZnO). Sun protection factor (SPF) of the aqueous extract of T. polium, the prepared gel, as well as the zinc oxide suspension alone and in combination with each other was determined spectrophotometrically based on a modified Transpore® tape method. Results and Conclusion: Obtained results showed that the T. polium extract has a wide band of ultraviolet radiation (UV) spectrum absorption ranging from 250 nm to 380 nm. SPF of the combination product in the ultraviolet B (UVB) area was greater than 80, revealing a synergistic action between ZnO and T. polium. The adsorption of flavonoids of T. polium on Zinc-oxide nanoparticles (ZnOn) slowed down their release thereby lengthening their persistence on the skin and contributing to further duration of action. PMID:24350038

  2. Alignment of graphene oxide nanostructures between microgap electrodes via dielectrophoresis for hydrogen gas sensing applications

    SciTech Connect

    Singh, Budhi; Wang, Jianwei; Rathi, Servin; Kim, Gil-Ho

    2015-05-18

    Graphene oxide (GO) nanostructures have been aligned between conducting electrodes via dielectrophoresis (DEP) with different electrical configurations. The arrangement of ground with respect to peak-to-peak voltage (V{sub pp}) plays a crucial role in manipulating the GO nanostructures. Grounds on both sides of the V{sub pp} electrode give an excellent linking of GO nanostructures which is explained by scanning electron microscopy and current-voltage characteristics. A finite element method simulation explains the electric field and voltage variation profile during DEP process. The optimized aligned GO nanostructures are used as hydrogen gas sensor with a sensitivity of 6.0% for 800 ppm hydrogen gas.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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

  4. Controlled Growth of one-dimensional zinc oxide nanostructures in the pulsed electrodeposition mode

    SciTech Connect

    Klochko, N. P. Khrypunov, G. S.; Myagchenko, Yu. O.; Melnychuk, E. E.; Kopach, V. R.; Klepikova, E. S.; Lyubov, V. M.; Kopach, A. V.

    2012-06-15

    Zinc oxide nanostructures are objects of study in the field of optoelectronics, solar power engineering, nanosensorics, and catalysis. For the purpose of the controlled growth of one-dimensional submicrometer zinc oxide structures in the pulsed electrodeposition mode, the effect of the pulse electrolysis parameters on the morphology of ZnO layers, their optical properties, and structural and substructural characteristics is determined using X-ray diffraction, optical spectrophotometry, and atomic-force microscopy. The possibility of fabricating arrays of ZnO nanowires with different geometrical shapes, perpendicular to the substrate surface, by varying the frequency of cathode-substrate potential pulses is shown.

  5. Different properties of aluminum doped zinc oxide nanostructured thin films prepared by radio frequency magnetron sputtering

    SciTech Connect

    Bidmeshkipour, Samina Shahtahmasebi, Nasser

    2013-06-15

    Aluminium doped zinc oxide (AZO) nanostructured thin films are prepared by radio frequency magnetron sputtering on glass substrate using specifically designed ZnO target containing different amount of Al{sub 2}O{sub 3} powder as the Al doping source. The optical properties of the aluminium doped zinc oxide films are investigated. The topography of the deposited films were investigated by Atomic Force Microscopy. Variation of the refractive index by annealing temperature are considered and it is seen that the refractive index increases by increasing the annealing temperature.

  6. Eco-friendly approach towards green synthesis of zinc oxide nanocrystals and its potential applications.

    PubMed

    Velmurugan, Palanivel; Park, Jung-Hee; Lee, Sang-Myeong; Yi, Young-Joo; Cho, Min; Jang, Jum-Suk; Myung, Hyun; Bang, Keuk-Soo; Oh, Byung-Taek

    2016-09-01

    In the present study, we investigated a novel green route for synthesis of zinc oxide (ZnO) nanocrystals using Prunus × yedoensis Matsumura leaf extract as a reducing agent without using any surfactant or external energy. Standard characterization studies were carried out to confirm the obtained product using UV-Vis spectra, SEM-EDS, FTIR, TEM, and XRD. In addition, the synthesized ZnO nanocrystals were coated onto fabric and leather samples to study their bacteriostatic effect against odor-causing bacteria Brevibacterium linens and Staphylococcus epidermidis. Zinc oxide nanocrystal-coated fabric and leather showed good activity against both bacteria.

  7. Synthesis, characterization and antimicrobial applications of zinc oxide nanoparticles loaded gum acacia/poly(SA) hydrogels.

    PubMed

    Bajpai, S K; Jadaun, Mamta; Tiwari, Seema

    2016-11-20

    In this work, zinc oxide nanoparticles were synthesized in-situ within the gum acacia/poly (acrylate) hydrogel network using hydrothermal approach. The synthesized zinc oxide nanoparticles were characterized by Surface plasmon resonance (SPR), X-Ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM). The water absorption behavior of ZnO/GA/poly(SA) hydrogels was investigated in the phosphate buffer saline (PBS) of pH 7.4 at 37°C. The water uptake data were analyzed with the help of various kinetic models. Finally, the antimicrobial action of nanocomposites was studied using E. coli as model bacteria.

  8. Doped and Undoped Zinc Oxide Nanostructures on Silicon Wafers

    NASA Astrophysics Data System (ADS)

    Chubenko, E.; Bondarenko, V.

    2013-05-01

    We present results of hydrothermal deposition of undoped and Al doped ZnO nanocrystals on nanocrystalline silicon. ZnO nanocrystals were deposited in an equimolar zinc nitride and hexamethylenetetramine solution. Aluminum nitride was used as Al precursor. The difference of the morphology of doped and undoped ZnO nanocrystals is discussed. Photoluminescence properties of the obtained nanocrystals are shown.

  9. Migration of point defects and a defect pair in zinc oxide using the dimer method

    SciTech Connect

    Chen, Dong; Gao, Fei; Dong, Mingdong; Liu, Bo

    2012-09-24

    The migration mechanism and the minimum energy path of vacancies, interstitials and an interstitial-vacancy pair in zinc oxide have been studied by the dimer method. The in-plane and out-of-plane migrations of zinc and oxygen vacancies are found to be anisotropic. The kick-out mechanism is energetically preferred to zinc and oxygen interstitials that can easily migrate through the ZnO crystal lattice. In addition, the migration process of an interstitial-vacancy pair as a complex of an octahedral oxygen interstitial and a zinc vacancy is dominated by an oxygen interstitial/zinc vacancy successive migration. The energy barriers indicate that the existence of oxygen interstitial in the defect pair can promote the mobility of zinc vacancy, whereas the migration of oxygen interstitial is slowed down due to the presence of zinc vacancy. In the end, we show a possible migration path of the interstitial-vacancy pair that can be dissociated through a set of displacement movements.

  10. Delamination and solvothermal decomposition of layered zinc hydroxysalt: Formation of bimodal zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Machado, Jyothi; Ravishankar, N.; Rajamathi, Michael

    2010-08-01

    Dodecylsulphate-intercalated zinc hydroxysalt, Zn 5(OH) 8(DS) 2·mH 2O delaminates to give monolayer colloidal dispersions in alcohols such as 1-butanol and ethylene glycol. The extent of delamination and the stability of the colloidal dispersion are comparable to those of layered double hydroxides. The solvothermal decomposition of the colloidal dispersion of the hydroxysalt in ethylene glycol yields a bimodal ZnO having a nanotubular structure decorated with nanosheets.

  11. Parameters of oxidative stress variation depending on the concentration of inorganic zinc compounds

    PubMed Central

    Grigorescu, R; Gruia, MI; Nacea, V; Nitu, C

    2015-01-01

    Zinc deficiency is a problem faced by a large number of people, a U.S. study showing that only 46% of the population aged over 71 years has the best amount of zinc in the body. Due to the very complex role of zinc deficiency in this trace, it can occur through a variety of symptoms affecting multiple body functions. Zinc was demonstrated to have the ability to neutralize free radicals protecting the body from the harmful effects of these effects, ultimately leading to atherosclerosis and cardiovascular disease derived from premature aging, the immune and immune disorders and increased risk of cancer. The purpose of the paper is to identify the role of antioxidant systems, with Zn2+ ions in the center of defense and decrease oxidative stress in dynamic interaction with malignant transformed cells. PMID:26664468

  12. Performance improvement of tin-doped zinc oxide thin-film transistor by novel channel modulation layer of indium tin oxide/tin zinc oxide

    NASA Astrophysics Data System (ADS)

    Chen, Zhuofa; Han, Dedong; Zhao, Nannan; Wu, Jing; Cong, Yingying; Dong, Junchen; Zhao, Feilong; Zhang, Shengdong; Zhang, Xing; Wang, Yi; Liu, Lifeng

    2015-04-01

    By applying a novel active modulation layer of indium tin oxide/tin zinc oxide (ITO/TZO), we have successfully fabricated high-performance bottom-gate-type dual-active-layer thin-film transistors (TFTs) on a glass substrate at a low temperature by a simple process. The as-fabricated dual-active-layer ITO/TZO TFTs exhibited excellent electrical properties compared with single-active-layer TZO TFTs. We found that the dual-layer ITO/TZO TFT with an optimized stack structure of ITO (5 nm)/TZO (45 nm) as the channel layer exhibits excellent properties, namely, a high saturation mobility of 204 cm2 V-1 s-1, a steep subthreshold slope of 219 mV/dec, a low threshold voltage of 0.8 V, and a high on-off current ratio of 4.3 × 107. A physical mechanism for the electrical improvement is also deduced. Owing to its advantages, namely, a low processing temperature, a high electrical performance, a simple process, and a low cost, this novel active modulation layer is highly promising for the manufacture of oxide semiconductor TFT and transparent displays.

  13. Fabrication Process Assessment and Negative Bias Illumination Stress Study of Indium-Gallium-Zinc Oxide and Zinc-Tin Oxide Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Hoshino, Ken

    Indium-gallium-zinc oxide (IGZO) and zinc-tin oxide (ZTO) are investigated for thin-film transistor (TFT) applications. Negative bias illumination stress (NBIS) is employed for electrical stability assessment. Unpassivated IGZO and ZTO TFTs suffer from severe NBIS instabilities. Zinc-tin-silicon oxide is found to be an effective passivation layer for IGZO and ZTO TFTs, significantly improving the NBIS stability. NBIS instabilities in unpassivated TFTs are attributed to an NBIS-induced desorption of chemisorbed oxygen from the channel layer top surface, exposing surface oxygen vacancies. A ZTSO layer protects the channel layer top surface from adsorbed gas interactions and also appears to reduce the density of oxygen vacancies. The best device architectures investigated with respect to TFT electrical performance are found to be staggered with aluminum electrodes for unpassivated TFTs and coplanar with ITO electrodes for ZTSO-passivated TFTs. Annealing in wet-O2 is not found to be effective for improving the performance of IGZO or ZTO TFTs or for reducing the post-deposition annealing temperature.

  14. Heat-sterilized silver oxide-zinc cells: Cycle life studies

    NASA Technical Reports Server (NTRS)

    Arms, J. T.

    1973-01-01

    A JPL study was conducted to evaluate the cell design parameters that contribute to the cycle life of sealed, heat-sterilized silver oxide-zinc cells. Test cells having a rated capacity of 4.2 A-h were fabricated using zinc oxide electrodes prepared by the sintered Teflon process. Two separator variations were evaluated, one having acrylic acid and the other methacrylic acid grafted to irradiated polyethylene film. Significant results of this study include the following: (1) cycle life in excess of 300 cycles was attained; (2) a zinc oxide/silver stoichiometric ratio of 1.5 resulted in greater cycle life than a ratio of 1.1, and similar cycle life to cells having a ratio of 2; (3) cells having methacrylic acid grafted separators suffered somewhat less in capacity loss due to zinc electrode shape change than cells having acrylic acid type; (4) use of acrylic acid grafted separators was slightly superior to the methacrylic acid type in respect to silver penetration; and (5) the inclusion of a layer of potassium titanate paper adjacent to the zinc electrodes resulted in cells that achieved higher cycle life before any of the group failed than that reached by cells of any other construction.

  15. Protective effects of zinc on oxidative stress enzymes in liver of protein-deficient rats.

    PubMed

    Sidhu, Pardeep; Garg, M L; Dhawan, D K

    2005-01-01

    Persons afflicted with protein malnutrition are generally deficient in a variety of essential micronutrients like zinc, copper, iron, and selenium, which in turn affects number of metabolic processes in the body. To evaluate the protective effects of zinc on the enzymes involved in oxidative stress induced in liver of protein-deficient rats, the current study was designed. Zinc sulfate at a dose level of 227 mg/L zinc in drinking water was administered to female Sprague-Dawley normal control as well as protein-deficient rats for a total duration of 8 weeks. The effects of zinc treatment in conditions of protein deficiency were studied on rat liver antioxidant enzymes, which included catalase, glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), glutathione reduced (GSH), and glutathione-S-transferase (GST). Protein deficiency in normal rats resulted in a significant increase in hepatic activities of catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase and the levels of lipid peroxidation. A significant inhibition in the levels of reduced glutathione and the enzyme activity of superoxide dismutase has been observed after protein deficiency in normal rats. Interestingly, Zn treatment to protein-deficient animals lowered already raised activity catalase, glutathione peroxidase, and glutathione-S-transferase and levels of lipid peroxidation to significant levels when compared to protein-deficient animals. Also, Zn treatment to the protein-deficient animals resulted in a significant elevation in the levels of GSH and SOD activity as compared to their respective controls, thereby indicating its effectiveness in regulating their levels in adverse conditions. It has also been observed that concentrations of zinc, copper, iron, and selenium were found to be decreased significantly in protein-deficient animals. However, the levels of these elements came back to within normal limits when zinc was administrated

  16. Zinc oxide nanostructure-modified textile and its application to biosensing, photocatalysis, and as antibacterial material.

    PubMed

    Hatamie, Amir; Khan, Azam; Golabi, Mohsen; Turner, Anthony P F; Beni, Valerio; Mak, Wing Cheung; Sadollahkhani, Azar; Alnoor, Hatim; Zargar, Behrooz; Bano, Sumaira; Nur, Omer; Willander, Magnus

    2015-10-06

    Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photocatalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photocatalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles.

  17. Functional zinc oxide nanostructures for electronic and energy applications

    NASA Astrophysics Data System (ADS)

    Prasad, Abhishek

    ZnO has proven to be a multifunctional material with important nanotechnological applications. ZnO nanostructures can be grown in various forms such as nanowires, nanorods, nanobelts, nanocombs etc. In this work, ZnO nanostructures are grown in a double quartz tube configuration thermal Chemical Vapor Deposition (CVD) system. We focus on functionalized ZnO Nanostructures by controlling their structures and tuning their properties for various applications. The following topics have been investigated: (1) We have fabricated various ZnO nanostructures using a thermal CVD technique. The growth parameters were optimized and studied for different nanostructures. (2) We have studied the application of ZnO nanowires (ZnONWs) for field effect transistors (FETs). Unintentional n-type conductivity was observed in our FETs based on as-grown ZnO NWs. We have then shown for the first time that controlled incorporation of hydrogen into ZnO NWs can introduce p-type characters to the nanowires. We further found that the n-type behaviors remained, leading to the ambipolar behaviors of hydrogen incorporated ZnO NWs. Importantly, the detected p- and n- type behaviors are stable for longer than two years when devices were kept in ambient conditions. All these can be explained by an ab initio model of Zn vacancy-Hydrogen complexes, which can serve as the donor, acceptors, or green photoluminescence quencher, depend on the number of hydrogen atoms involved. (3) Next ZnONWs were tested for electron field emission. We focus on reducing the threshold field (Eth) of field emission from non-aligned ZnO NWs. As encouraged by our results on enhancing the conductivity of ZnO NWs by hydrogen annealing described in Chapter 3, we have studied the effect of hydrogen annealing for improving field emission behavior of our ZnO NWs. We found that optimally annealed ZnO NWs offered much lower threshold electric field and improved emission stability. We also studied field emission from ZnO NWs at moderate

  18. Fabricating vertically aligned sub-20 nm Si nanowire arrays by chemical etching and thermal oxidation.

    PubMed

    Li, Luping; Fang, Yin; Xu, Cheng; Zhao, Yang; Zang, Nanzhi; Jiang, Peng; Ziegler, Kirk J

    2016-04-22

    Silicon nanowires (SiNWs) are appealing building blocks in various applications, including photovoltaics, photonics, and sensors. Fabricating SiNW arrays with diameters <100 nm remains challenging through conventional top-down approaches. In this work, chemical etching and thermal oxidation are combined to fabricate vertically aligned, sub-20 nm SiNW arrays. Defect-free SiNWs with diameters between 95 and 200 nm are first fabricated by nanosphere (NS) lithography and chemical etching. The key aspects for defect-free SiNW fabrication are identified as: (1) achieving a high etching selectivity during NS size reduction; (2) retaining the circular NS shape with smooth sidewalls; and (3) using a directional metal deposition technique. SiNWs with identical spacing but variable diameters are demonstrated by changing the reactive ion etching power. The diameter of the SiNWs is reduced by thermal oxidation, where self-limiting oxidation is encountered after oxidizing the SiNWs at 950 °C for 1 h. A second oxidation is performed to achieve vertically aligned, sub-20 nm SiNW arrays. Si/SiO2 core/shell NWs are obtained before removing the oxidized shell. HRTEM imaging shows that the SiNWs have excellent crystallinity.

  19. Solution-processed zinc oxide field-effect transistors based on self-assembly of colloidal nanorods.

    PubMed

    Sun, Baoquan; Sirringhaus, Henning

    2005-12-01

    Colloidal zinc oxide (ZnO) nanocrystals are attractive candidates for a low-temperature and solution-processible semiconductor for high-performance thin-film field-effect transistors (TFTs). Here we show that by controlling the shape of the nanocrystals from spheres to rods the semiconducting properties of spin-coated ZnO films can be much improved as a result of increasing particle size and self-alignment of the nanorods along the substrate. Postdeposition hydrothermal growth in an aqueous zinc ion solution has been found to further enhance grain size and connectivity and improve device performance. TFT devices made from 65-nm-long and 10-nm-wide nanorods deposited by spin coating have been fabricated at moderate temperatures of 230 degrees C with mobilities of 0.61 cm(2)V(-1)s(-1) and on/off ratios of 3 x 10(5) after postdeposition growth, which is comparable to the characteristics of TFTs fabricated by traditional sputtering methods.

  20. Chlorine sensing properties of zinc oxide resistive gas sensor doped with platinum

    NASA Astrophysics Data System (ADS)

    Fiedot, M.; Suchorska-Woźniak, P.; Rac, O.; Nawrot, W.; Teterycz, H.

    2016-11-01

    In presented studies resistive chlorine gas sensor with gas sensitive layer in the form of zinc oxide microrods doped with platinum was developed. The growth of active layer was carried out in water solution containing zinc nitrate (V), hexamethylenetetramine and chloroplatinic acid using the chemical bath deposition method. The structure and morphology of obtained sensors was characterized by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). To determine the chlorine gas sensing properties Temperature-Stimulated Conductance method (TSC) was used. During the measurements sensor was tested in a reference atmosphere and an atmosphere with 2, 5 or 8 ppm of chlorine. Obtained results have shown that zinc oxide microrods doped with platinum were obtained. TSC measurements showed that developed sensor allows to detect chlorine with very good sensitivity.

  1. Influence of Anodic Conditions on Self-ordered Growth of Highly Aligned Titanium Oxide Nanopores

    PubMed Central

    2007-01-01

    Self-aligned nanoporous TiO2templates synthesized via dc current electrochemical anodization have been carefully analyzed. The influence of environmental temperature during the anodization, ranging from 2 °C to ambient, on the structure and morphology of the nanoporous oxide formation has been investigated, as well as that of the HF electrolyte chemical composition, its concentration and their mixtures with other acids employed for the anodization. Arrays of self-assembled titania nanopores with inner pores diameter ranging between 50 and 100 nm, wall thickness around 20–60 nm and 300 nm in length, are grown in amorphous phase, vertical to the Ti substrate, parallel aligned to each other and uniformly disordering distributed over all the sample surface. Additional remarks about the photoluminiscence properties of the titania nanoporous templates and the magnetic behavior of the Ni filled nanoporous semiconductor Ti oxide template are also included.

  2. Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics

    SciTech Connect

    Demyanets, L. N. Li, L. E.; Lavrikov, A. S.; Nikitin, S. V.

    2010-01-15

    Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

  3. Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics

    NASA Astrophysics Data System (ADS)

    Demyanets, L. N.; Li, L. E.; Lavrikov, A. S.; Nikitin, S. V.

    2010-01-01

    Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

  4. [Zinc oxide phosphate cement studies on the usefulness of Firmat].

    PubMed

    Glockmann, E; Glockmann, I; Hörenz, D; Lange, G; Reichardt, R; Schwarzburg, G

    1976-01-01

    The aim of the present investigations was to evaluate the Firmat zinc oxyphosphate cement in comparison with other brands, especially Adhesor normalhartend. The results obtained show that Firmat is a fast-setting phosphate cement which is not suited for polyhedral cavity linings. Time and material-consuming reworking is necessary. For temporary fillings, a temporary filling material should be used which is sufficiently solid, but easier to remove.

  5. Atomic layer deposition of tin oxide and zinc tin oxide using tetraethyltin and ozone

    SciTech Connect

    Warner, Ellis J.; Gladfelter, Wayne L.; Johnson, Forrest; Campbell, Stephen A.

    2015-03-15

    Silicon or glass substrates exposed to sequential pulses of tetraethyltin (TET) and ozone (O{sub 3}) were coated with thin films of SnO{sub 2}. Self-limiting deposition was found using 8 s pulse times, and a uniform thickness per cycle (TPC) of 0.2 nm/cycle was observed in a small, yet reproducible, temperature window from 290 to 320 °C. The as-deposited, stoichiometric SnO{sub 2} films were amorphous and transparent above 400 nm. Interspersing pulses of diethylzinc and O{sub 3} among the TET:O{sub 3} pulses resulted in deposition of zinc tin oxide films, where the fraction of tin, defined as [at. % Sn/(at. % Sn + at. % Zn)], was controlled by the ratio of TET pulses, specifically n{sub TET}:(n{sub TET} + n{sub DEZ}) where n{sub TET} and n{sub DEZ} are the number of precursor/O{sub 3} subcycles within each atomic layer deposition (ALD) supercycle. Based on film thickness and composition measurements, the TET pulse time required to reach saturation in the TPC of SnO{sub 2} on ZnO surfaces was increased to >30 s. Under these conditions, film stoichiometry as a function of the TET pulse ratio was consistent with the model devised by Elliott and Nilsen. The as-deposited zinc tin oxide (ZTO) films were amorphous and remained so even after annealing at 450 °C in air for 1 h. The optical bandgap of the transparent ZTO films increased as the tin concentration increased. Hall measurements established that the n-type ZTO carrier concentration was 3 × 10{sup 17} and 4 × 10{sup 18} cm{sup −3} for fractional tin concentrations of 0.28 and 0.63, respectively. The carrier mobility decreased as the concentration of tin increased. A broken gap pn junction was fabricated using ALD-deposited ZTO and a sputtered layer of cuprous oxide. The junction demonstrated ohmic behavior and low resistance consistent with similar junctions prepared using sputter-deposited ZTO.

  6. The cytotoxic effects of titanium oxide and zinc oxide nanoparticles oh Human Cervical Adenocarcinoma cell membranes

    NASA Astrophysics Data System (ADS)

    Mironava, Tatsiana; Applebaum, Ariella; Applebaum, Eliana; Guterman, Shoshana; Applebaum, Kayla; Grossman, Daniel; Gordon, Chris; Brink, Peter; Wang, H. Z.; Rafailovich, Miriam

    2013-03-01

    The importance of titanium dioxide (TiO2) and zinc oxide (ZnO), inorganic metal oxides nanoparticles (NPs) stems from their ubiquitous applications in personal care products, solar cells and food whitening agents. Hence, these NPs come in direct contact with the skin, digestive tracts and are absorbed into human tissues. Currently, TiO2 and ZnO are considered safe commercial ingredients by the material safety data sheets with no reported evidence of carcinogenicity or ecotoxicity, and do not classify either NP as a toxic substance. This study examined the direct effects of TiO2 and ZnO on HeLa cells, a human cervical adenocarcinonma cell line, and their membrane mechanics. The whole cell patch-clamp technique was used in addition to immunohistochemistry staining, TEM and atomic force microscopy (AFM). Additionally, we examined the effects of dexamethasone (DXM), a glucocorticoid steroid known to have an effect on cell membrane mechanics. Overall, TiO2 and ZnO seemed to have an adverse effect on cell membrane mechanics by effecting cell proliferation, altering cellular structure, decreasing cell-cell adhesion, activating existing ion channels, increasing membrane permeability, and possibly disrupting cell signaling.

  7. Cobalt-phosphate-assisted photoelectrochemical water oxidation by arrays of molybdenum-doped zinc oxide nanorods.

    PubMed

    Lin, Yan-Gu; Hsu, Yu-Kuei; Chen, Ying-Chu; Lee, Bing-Wei; Hwang, Jih-Shang; Chen, Li-Chyong; Chen, Kuei-Hsien

    2014-09-01

    We report the first demonstration of cobalt phosphate (Co-Pi)-assisted molybdenum-doped zinc oxide nanorods (Zn(1-x)Mo(x)O NRs) as visible-light-sensitive photofunctional electrodes to fundamentally improve the performance of ZnO NRs for photoelectrochemical (PEC) water splitting. A maximum photoconversion efficiency as high as 1.05% was achieved, at a photocurrent density of 1.4 mA cm(-2). More importantly, in addition to achieve the maximum incident photon to current conversion efficiency (IPCE) value of 86%, it could be noted that the IPCE of Zn(1-x)Mo(x)O photoanodes under monochromatic illumination (450 nm) is up to 12%. Our PEC performances are comparable to those of many oxide-based photoanodes in recent reports. The improvement in photoactivity of PEC water splitting may be attributed to the enhanced visible-light absorption, increased charge-carrier densities, and improved interfacial charge-transfer kinetics due to the combined effect of molybdenum incorporation and Co-Pi modification, contributing to photocatalysis. The new design of constructing highly photoactive Co-Pi-assisted Zn(1-x)Mo(x)O photoanodes enriches knowledge on doping and advances the development of high-efficiency photoelectrodes in the solar-hydrogen field.

  8. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    EPA Science Inventory

    Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2•6H2O functionalization of zeolite. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The adsorption capacity of the adsorbents at 21...

  9. Vapor-phase growth of transparent zinc oxide ceramics with c -axis orientation

    SciTech Connect

    Noritake, F.; Yamamoto, N.; Horiguchi, Y. ); Fujitsu, S.; Koumoto, K. ); Yanagida, H. )

    1991-01-01

    Large transparent specimens of polycrystalline zinc oxide with c-axis orientation have been prepared by the vapor transport method. Optical transmittance is 80% to 90% at 800 nm. X-ray diffraction peaks from faces other than (001) are negligible.

  10. Laser forming of structures of zinc oxide on a surface of products from copper alloys

    NASA Astrophysics Data System (ADS)

    Abramov, D. V.; Gorudko, T. N.; Koblov, A. N.; Nogtev, D. S.; Novikova, O. A.

    Laser formation of a protective zinc oxide layer on a surface of products from copper alloys is present. This layer is formed with using of carbon nanotubes. Destructions of the basic material are avoided or minimized at laser nanostructuring of product surfaces. Such laser processing can be made repeatedly. Offered covering have self-clearing and water-repellent properties.

  11. Formulation of nano-zinc oxide into biocomposite beads for dye decolorization

    NASA Astrophysics Data System (ADS)

    Elkady, M. F.; Hassan, H. Shokry; El-Shazly, A. H.

    2015-03-01

    Zinc oxide nano-powder was prepared using sol-gel technique to be encapsulated onto polymeric blend composed from alginate and polyvinyl alcohol to fabricate novel bio-composite beads of nano-zinc oxide. The XRD patterns of both zinc oxide nano-powder and its polymeric hybrid were crystalline in their nature. The FTIR analysis of the fabricated ZnO polymeric hybrid confirms the binding between zinc oxide and the polymeric matrix. The BET analysis demonstrated that the calculated specific surface area of the formulated ZnO beads that equal to 22.8 m2/g is comparatively less than that of the free ZnO nano-powdered that equivalent to 64.9 m2/g. The thermal stability of ZnO nano-powdered dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500rpm. Moreover, this hybrid beads are chemically stable at the acidic media. The formulated ZnO hybrid beads verified to be good adsorbent material for C.I basic blue 41 (CB41).

  12. Biosynthesis of silver and zinc oxide nanoparticles using Pichia fermentans JA2 and their antimicrobial property

    NASA Astrophysics Data System (ADS)

    Chauhan, Ritika; Reddy, Arpita; Abraham, Jayanthi

    2015-01-01

    The development of eco-friendly alternative to chemical synthesis of metal nanoparticles is of great challenge among researchers. The present study aimed to investigate the biological synthesis, characterization, antimicrobial study and synergistic effect of silver and zinc oxide nanoparticles against clinical pathogens using Pichia fermentans JA2. The extracellular biosynthesis of silver and zinc oxide nanoparticles was investigated using Pichia fermentans JA2 isolated from spoiled fruit pulp bought in Vellore local market. The crystalline and stable metallic nanoparticles were characterized evolving several analytical techniques including UV-visible spectrophotometer, X-ray diffraction pattern analysis and FE-scanning electron microscope with EDX-analysis. The biosynthesized metallic nanoparticles were tested for their antimicrobial property against medically important Gram positive, Gram negative and fungal pathogenic microorganisms. Furthermore, the biosynthesized nanoparticles were also evaluated for their increased antimicrobial activities with various commercially available antibiotics against clinical pathogens. The biosynthesized silver nanoparticles inhibited most of the Gram negative clinical pathogens, whereas zinc oxide nanoparticles were able to inhibit only Pseudomonas aeruginosa. The combined effect of standard antibiotic disc and biosynthesized metallic nanoparticles enhanced the inhibitory effect against clinical pathogens. The biological synthesis of silver and zinc oxide nanoparticles is a novel and cost-effective approach over harmful chemical synthesis techniques. The metallic nanoparticles synthesized using Pichia fermentans JA2 possess potent inhibitory effect that offers valuable contribution to pharmaceutical associations.

  13. Bio-inspired band gap engineering of zinc oxide by intracrystalline incorporation of amino acids.

    PubMed

    Brif, Anastasia; Ankonina, Guy; Drathen, Christina; Pokroy, Boaz

    2014-01-22

    Bandgap engineering of zinc oxide semiconductors can be achieved using a bio-inspired method. During a bioInspired crystallization process, incorporation of amino acids into the crystal structure of ZnO induces lattice strain that leads to linear bandgap shifts. This allows for fine tuning of the bandgap in a bio-inspired route.

  14. Laser energy density, structure and properties of pulsed-laser deposited zinc oxide films

    NASA Astrophysics Data System (ADS)

    Tsoutsouva, M. G.; Panagopoulos, C. N.; Kompitsas, M.

    2011-05-01

    Zinc oxide thin films were deposited on soda lime glass substrates by pulsed laser deposition in an oxygen-reactive atmosphere at 20 Pa and a constant substrate temperature at 300 °C. A pulsed KrF excimer laser, operated at 248 nm with pulse duration 10 ns, was used to ablate the ceramic zinc oxide target. The structure, the optical and electrical properties of the as-deposited films were studied in dependence of the laser energy density in the 1.2-2.8 J/cm 2 range, with the aid of X-ray Diffraction, Atomic Force Microscope, Transmission Spectroscopy techniques, and the Van der Pauw method, respectively. The results indicated that the structural and optical properties of the zinc oxide films were improved by increasing the laser energy density of the ablating laser. The surface roughness of the zinc oxide film increased with the decrease of laser energy density and both the optical bang gap and the electrical resistivity of the film were significantly affected by the laser energy density.

  15. Ternary and coupled binary zinc tin oxide nanopowders: Synthesis, characterization, and potential application in photocatalytic processes

    SciTech Connect

    Ivetić, T.B.; Finčur, N.L.; Đačanin, Lj. R.; Abramović, B.F.; Lukić-Petrović, S.R.

    2015-02-15

    Highlights: • Mechanochemically synthesized nanocrystalline zinc tin oxide (ZTO) powders. • Photocatalytic degradation of alprazolam in the presence of ZTO water suspensions. • Coupled binary ZTO exhibits enhanced photocatalytic activity compared to ternary ZTO. - Abstract: In this paper, ternary and coupled binary zinc tin oxide nanocrystalline powders were prepared via simple solid-state mechanochemical method. X-ray diffraction, scanning electron microscopy, Raman and reflectance spectroscopy were used to study the structure and optical properties of the obtained powder samples. The thermal behavior of zinc tin oxide system was examined through simultaneous thermogravimetric-differential scanning calorimetric analysis. The efficiencies of ternary (Zn{sub 2}SnO{sub 4} and ZnSnO{sub 3}) and coupled binary (ZnO/SnO{sub 2}) zinc tin oxide water suspensions in the photocatalytic degradation of alprazolam, short-acting anxiolytic of the benzodiazepine class of psychoactive drugs, under UV irradiation were determined and compared with the efficiency of pure ZnO and SnO{sub 2}.

  16. An Atomistic View of the Incipient Growth of Zinc Oxide Nanolayers

    SciTech Connect

    Chu, Manh Hung; Tian, Liang; Chaker, Ahmad; Cantelli, Valentina; Ouled, Toufik; Boichot, Raphaël; Crisci, Alexandre; Lay, Sabine; Richard, Marie-Ingrid; Thomas, Olivier; Deschanvres, Jean-Luc; Renevier, Hubert; Fong, Dillon D.; Ciatto, Gianluca

    2016-09-07

    The growth of zinc oxide thin films by atomic layer deposition is believed to proceed through an embryonic step in which three-dimensional nanoislands form and then coalesce to trigger a layer-by-layer growth mode. This transient initial state is characterized by a poorly ordered atomic structure, which may be inaccessible by X-ray diffraction techniques. In this work, we apply X-ray absorption spectroscopy in situ to address the local structure of Zn after each atomic layer deposition cycle, using a custom-built reactor mounted at a synchrotron beamline, and we shed light on the atomistic mechanisms taking place during the first stages of the growth. We find that such mechanisms are surprisingly different for zinc oxide growth on amorphous (silica) and crystalline (sapphire) substrate. Ab initio simulations and quantitative data analysis allow the formulation of a comprehensive growth model, based on the different effects of surface atoms and grain boundaries in the nanoscale islands, and the consequent induced local disorder. From a comparison of these specttoscopy results with those from X-ray diffraction reported recently, we observe that the final structure of the zinc oxide nanolayers depends strongly on the mechanisms taking place during the initial stages of growth. The approach followed here for the case of zinc oxide will be of general interest for characterizing and optimizing the growth and properties of more complex nanostructures.

  17. Liquid crystal terahertz phase shifters with functional indium-tin-oxide nanostructures for biasing and alignment

    NASA Astrophysics Data System (ADS)

    Yang, Chan-Shan; Tang, Tsung-Ta; Pan, Ru-Pin; Yu, Peichen; Pan, Ci-Ling

    2014-04-01

    Indium Tin Oxide (ITO) nanowhiskers (NWhs) obliquely evaporated by electron-beam glancing-angle deposition can serve simultaneously as transparent electrodes and alignment layer for liquid crystal (LC) devices in the terahertz (THz) frequency range. To demonstrate, we constructed a THz LC phase shifter with ITO NWhs. Phase shift exceeding π/2 at 1.0 THz was achieved in a ˜517 μm-thick cell. The phase shifter exhibits high transmittance (˜78%). The driving voltage required for quarter-wave operation is as low as 5.66 V (rms), compatible with complementary metal-oxide-semiconductor (CMOS) and thin-film transistor (TFT) technologies.

  18. Liquid crystal terahertz phase shifters with functional indium-tin-oxide nanostructures for biasing and alignment

    SciTech Connect

    Yang, Chan-Shan; Tang, Tsung-Ta; Pan, Ru-Pin; Yu, Peichen; Pan, Ci-Ling

    2014-04-07

    Indium Tin Oxide (ITO) nanowhiskers (NWhs) obliquely evaporated by electron-beam glancing-angle deposition can serve simultaneously as transparent electrodes and alignment layer for liquid crystal (LC) devices in the terahertz (THz) frequency range. To demonstrate, we constructed a THz LC phase shifter with ITO NWhs. Phase shift exceeding π/2 at 1.0 THz was achieved in a ∼517 μm-thick cell. The phase shifter exhibits high transmittance (∼78%). The driving voltage required for quarter-wave operation is as low as 5.66 V (rms), compatible with complementary metal-oxide-semiconductor (CMOS) and thin-film transistor (TFT) technologies.

  19. Ultraflexible polymer solar cells using amorphous zinc-indium-tin oxide transparent electrodes.

    PubMed

    Zhou, Nanjia; Buchholz, Donald B; Zhu, Guang; Yu, Xinge; Lin, Hui; Facchetti, Antonio; Marks, Tobin J; Chang, Robert P H

    2014-02-01

    Polymer solar cells are fabricated on highly conductive, transparent amorphous zinc indium tin oxide (a-ZITO) electrodes. For two representative active layer donor polymers, P3HT and PTB7, the power conversion efficiencies (PCEs) are comparable to reference devices using polycrystalline indium tin oxide (ITO) electrodes. Benefitting from the amorphous character of a-ZITO, the new devices are highly flexible and can be repeatedly bent to a radius of 5 mm without significant PCE reduction.

  20. The synthesis of zinc oxide nanoparticles from zinc acetylacetonate hydrate and 1-butanol or isobutanol.

    PubMed

    Ambrozic, Gabriela; Skapin, Sreco D; Zigon, Majda; Orel, Zorica Crnjak

    2010-06-15

    ZnO nanoparticles of different sizes, from 20 to 200 nm in length, and morphologies, nanorods and coral-like structures, were synthesized via a simple one-pot synthesis by refluxing an oversaturated solution of zinc acetylacetonate hydrate in 1-butanol and isobutanol. On the basis of (1)H and (13)C NMR experiments, the reactions in both alcohols were found to proceed via the alcoholytic C-C cleavage of the acetylacetonate ligand, followed by the hydrolytic formation of the reactive Zn-OH intermediate from the water molecules present in the precursor hydrate species and/or those released during the condensation cycle. The zinc acetylacetonate conversion into ZnO in isobutanol is significantly slower than in the case when 1-butanol was used as both the medium and the reagent. FE-SEM studies showed that in 1-butanol the growth of the rod-shaped particles occurs via the agglomeration of ZnO primary particles that are less than 10 nm in size. The morphology of the particles formed in the isobutanol is time dependent, with the final coral-like structures developing from initially formed bundle-like structures.

  1. Effect of solvents on the synthesis of nano-size zinc oxide and its properties

    SciTech Connect

    Kanade, K.G.; Kale, B.B. . E-mail: kbbb1@yahoo.com; Aiyer, R.C.; Das, B.K.

    2006-03-09

    The effect of the solvents on particle size and morphology of ZnO is investigated. The optical properties of nano ZnO were studied extensively. During this study, zinc oxalate was prepared in aqueous and organic solvents using zinc acetate and oxalic acid as precursors. The thermo-gravimetric analysis (TGA/DTA) showed formation of ZnO at 400 deg. C. Nano-size zinc oxide was obtained by thermal decomposition of aqueous and organic mediated zinc oxalate at 450 deg. C. The phase purity was confirmed by XRD and crystal size determined from transmission electron microscopy (TEM) was found to be 22-25 nm for the aqueous and 14 -17 nm in organic mediated ZnO. Scanning electron microscope (SEM) also revealed different nature of surfaces and microstructures for zinc oxide obtained in aqueous and organic solvents. The UV absorption spectra showed sharp absorption peaks with a blue shift for organic mediated ZnO, due to monodispersity and lower particle size. Sharp peaks and absence of any impurity peaks in photoluminescence spectra (PLS) complement the above observations.

  2. Radiation Stability of Zinc Oxide Pigment Modified by Zirconium Oxide and Aluminum Oxide Nanopowders

    SciTech Connect

    Mikhailov, M. M.; Neshchimenko, V. V.; Li Chundong

    2009-01-05

    The effect on the reflective spectra of heat treatment and modification of ZnO pigments by 1-30 wt.%ZrO{sub 2} and Al{sub 2}O{sub 3} nanoparticles has been investigated before and after irradiation by 100 keV protons with a fluence of 5x10{sup 15} cm{sup -2}. It is established that with the optimum concentration of 5 wt.% nanoparticles and the temperature of 800 deg. C a 20% increase in the radiation stability is observed for the modified ZnO pigment in comparison with the not modified pigment. The decrease of absorption in the modified pigments is determined by the decrease of the intensity of the absorption bands of the zinc vacancies (V{sub zn}{sup -}), oxygen vacancies (V{sub o}{sup +}) and donor-acceptor couples (V{sub zn}-{sup -}Zn{sub i}{sup 0})

  3. Electrical properties of zinc-oxide-based thin-film transistors using strontium-oxide-doped semiconductors

    NASA Astrophysics Data System (ADS)

    Wu, Shao-Hang; Zhang, Nan; Hu, Yong-Sheng; Chen, Hong; Jiang, Da-Peng; Liu, Xing-Yuan

    2015-10-01

    Strontium-zinc-oxide (SrZnO) films forming the semiconductor layers of thin-film transistors (TFTs) are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide (ZnO) with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel. Project supported by the National Natural Science Foundation of China (Grant No. 6140031454) and the Innovation Program of Chinese Academy of Sciences and State Key Laboratory of Luminescence and Applications.

  4. Synthesis and characterization of lanthanum doped zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Vinod; Sonia, Suman, Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    La doped ZnO (Zn1-xLaxO, x = 0, 3, 6 and 9) were prepared via chemical co-precipitation method using Zinc Acetate, Lanthanum Acetate and Sodium Hydroxide at 50°C. Hydrate nanoparticles were annealed in air at 300°C for 3 hours. The synthesized samples have been characterized by powder X-ray diffraction and UV-Visiblespectrophotometer. The XRD measurement revealsthat the prepared nanoparticles have different microstructure without changing a hexagonal wurtzite structure. The result shows the change in nanoparticles size with the increment of lanthanum concentration for lower concentration for x = 0 to 6 and decreases at x = 9.

  5. Surface morphology and electrical transport of rapid thermal annealed chromium-doped indium zinc oxides: The influence of zinc interstitials and out-diffusion

    SciTech Connect

    Hsu, C. Y.

    2013-12-09

    We investigate the complex impedance (CI) spectra of chromium-doped indium zinc oxide (CIZO) films with different rapid thermal annealing (RTA) temperatures. The CI spectra drawn from the impedance contributions of Zn-O and In-O bondings in CIZO films were analyzed by two sets of parallel resistance and capacitance components in series. The result demonstrates that zinc interstitials controls electron concentration and transition of electrical transport from semiconducting to metallic. At higher RTA temperature, high-density zinc interstitial promotes Zn atom diffusion from the surface, modifying surface morphology.

  6. Investigation of reaction conditions on morphology and optical properties of Zinc Oxide Nanorods

    NASA Astrophysics Data System (ADS)

    Almodarresiyeh, H. A.; Abakshonok, A. V.; Agabekov, V. E.; Eryomin, A. N.; Shahab, S. N.

    2014-08-01

    Zinc oxide nanoparticles (ZnO NPs) were synthesized by precipitation method in the presence of various polymers. Rod shaped ZnO NPs (length ~ 1 micron) were obtained at 70 °C in a reaction medium containing 10-20 mM of zinc nitrate hexahydrate (Zn(NO3)2·6H2O), 0.05-0.1 mg/ml of polyethylenimine (PEI) and 20 mM of hexamethylenetetramine (HMT). Properties of ZnO NPs were characterized by fluorescence, UV-visible spectroscopy, atomic force and transmission electron microscopy.

  7. A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip.

    PubMed

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2011-01-01

    A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

  8. Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide

    SciTech Connect

    Russo, V.; Ghidelli, M.; Gondoni, P.

    2014-02-21

    In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325 nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

  9. Characterization of zinc oxide thin film for pH detector

    NASA Astrophysics Data System (ADS)

    Hashim, Uda; Fathil, M. F. M.; Arshad, M. K. Md; Gopinath, Subash C. B.; Uda, M. N. A.

    2017-03-01

    This paper presents the fabrication process of the zinc oxide thin films for using to act as pH detection by using different PH solution. Sol-gel solution technique is used for preparing zinc oxide seed solution, followed by metal oxide deposition process by using spin coater on the silicon dioxide. Silicon dioxide layer is grown on the silicon wafer, then, ZnO seed solution is deposited on the silicon layer, baked, and annealing process carried on to undergo the characterization of its surface morphology, structural and crystalline phase. Electrical characterization is showed by using PH 4, 7, and 10 is dropped on the surface of the die, in addition, APTES solution is used as linker and also as a references of the electrical characterization.

  10. A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2011-01-01

    A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature. PMID:22247656

  11. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    SciTech Connect

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli; Zhou, Lingyu; Zhang, Jian

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  12. Contrasting the grain boundary-affected performance of zinc and indium oxide transparent conductors

    NASA Astrophysics Data System (ADS)

    Vai, A. T.; Rashidi, N.; Fang, Y.; Kuznetsov, V. L.; Edwards, P. P.

    2016-06-01

    Zinc oxide-based transparent conductors have long been advanced for their potential as low-cost, earth-abundant replacements for the indium oxide-based materials that currently dominate in practical applications. However, this potential has yet to be realized because of the difficulties in producing zinc oxide thin films with the necessary high levels of electrical conductivity and environmental stability that are readily achieved using indium oxide. To better understand the fundamental reasons for this, polycrystalline zinc and indium oxide thin films were prepared across a range of deposition temperatures using the technique of spray pyrolysis. Electrical transport measurements of these samples both as a function of temperature and UV irradiation were correlated with film morphology to illustrate that the different grain boundary behaviour of these two materials is one of the key reasons for their divergent performance. This is a critical challenge that must be addressed before any substantial increase in the adoption of ZnO-based transparent conductors can take place.

  13. Chemism and kinetics of the oxidation of zinc-calcium oxysulfide

    NASA Astrophysics Data System (ADS)

    Gulyaeva, R. I.; Selivanov, E. N.; Mansurova, A. N.

    2013-05-01

    The sequence of phase transformations and the kinetics of the solid-phase (heating to 1273 K) oxidation of zinc-calcium oxysulfide CaZnSO with air are determined by thermodynamic, thermogravimetric, mass spectrometric, and X-ray diffraction analyses. The oxidation process is shown to be accompanied by the formation of the CaSO4 and ZnO phases depending on the heating conditions, as well as by the formation of CaO with SO2 evolution. The two-stage oxidation of CaZnSO is interpreted by the Avrami-Erofeev kinetic equations with activation energies of 190 and 422 kJ/mol.

  14. Dimensional Tailoring of Hydrothermally Grown Zinc Oxide Nanowire Arrays.

    PubMed

    Cheng, Jayce J; Nicaise, Samuel M; Berggren, Karl K; Gradečak, Silvija

    2016-01-13

    Hydrothermally synthesized ZnO nanowire arrays are critical components in a range of nanostructured semiconductor devices. The device performance is governed by relevant nanowire morphological parameters that cannot be fully controlled during bulk hydrothermal synthesis due to its transient nature. Here, we maintain homeostatic zinc concentration, pH, and temperature by employing continuous flow synthesis and demonstrate independent tailoring of nanowire array dimensions including areal density, length, and diameter on device-relevant length scales. By applying diffusion/reaction-limited analysis, we separate the effect of local diffusive transport from the c-plane surface reaction rate and identify direct incorporation as the c-plane growth mechanism. Our analysis defines guidelines for precise and independent control of the nanowire length and diameter by operating in rate-limiting regimes. We validate its utility by using surface adsorbents that limit reaction rate to obtain spatially uniform vertical growth rates across a patterned substrate.

  15. The effects of gold coated and uncoated zinc oxide nanohexagons on the photophysicochemical properties of the low symmetry zinc phthalocyanine

    NASA Astrophysics Data System (ADS)

    D'Souza, Sarah; Ogbodu, Racheal; Nyokong, Tebello

    2015-11-01

    A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm-2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.

  16. Effect of Zinc Oxide Film Deposition Position on the Characteristics of Zinc Oxide Thin Film Transistors Fabricated by Low-Temperature Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Takechi, Kazushige; Nakata, Mitsuru; Eguchi, Toshimasa; Otsuki, Shigeyoshi; Yamaguchi, Hirotaka; Kaneko, Setsuo

    2008-09-01

    We report on the effect of zinc oxide (ZnO) film deposition position on the characteristics of ZnO thin-film transistors (TFTs) fabricated by magnetron sputtering with no intentional heating of the substrate. We evaluate the properties of ZnO (channel semiconductor) films deposited at various positions with respect to the target position. We show that the film deposition at a position off-centered from the target results in good TFT characteristics. This might be due to the fact that the off-centered deposition position is effective for suppressing the effect of energetic negative ions in the plasma.

  17. In vitro effect of zinc on oxidative changes in human semen.

    PubMed

    Gavella, M; Lipovac, V

    1998-11-01

    The in vitro effect of zinc on superoxide anion (O2-) generation and on experimentally induced lipid peroxidation (LPO) in spermatozoa of infertile men was investigated. Washed spermatozoa pre-incubated for 30 min at 37 degrees C in the presence of 1 or 3 mmol l-1 zinc, released less superoxide anions (P < 0.03 and P < 0.02, respectively; n = 9) than the untreated spermatozoa. Similar results were obtained using activated polymorphonuclear leukocytes (1 x 10(6) cells ml-1) in the presence of 1 or 3 mmol l-1 Zn (P < 0.001 and P < 0.0002, respectively; n = 9). The in vitro evidence of the inhibitory effect of zinc on O2- generation by human spermatozoa and leukocytes indicates that zinc may act in vivo as a scavenger of excessive O2- production by defective spermatozoa and/or leukocytes in semen after ejaculation. A significant stimulatory effect of Zn (3 mmol l-1) on iron-induced lipid peroxidation, measured by the formation of thiobarbituric acid reactive substances (TBARS), was detected in the spermatozoa of 16 normo- and 17 asthenozoospermic males (P < 0.0001 and P < 0.001, respectively). In 11 samples with sperm concentration 20.3 +/- 2.1 x 10(6) ml-1, exhibiting initial TBARS concentration two times higher than in normo- and asthenozoospermic samples (40.5 +/- 2.4 vs. 17.1 +/- 1.1 and 28.5 +/- 4.1 nmoles TBARS 10(-8) spermatozoa), no effect of zinc on the LPO rate was found. The observed inhibitory effect of zinc on superoxide anion regardless of the initial O2- level and stimulatory effect of zinc depending on the initial LPO rate in human spermatozoa suggests that this metal ion participates in the oxidative changes occurring after ejaculation and thus may modulate the properties of germ cells.

  18. The role of pH variation on the growth of zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Wahab, Rizwan; Ansari, S. G.; Kim, Young Soon; Song, Minwu; Shin, Hyung-Shik

    2009-02-01

    In this paper we present a systematic study on the morphological variation of ZnO nanostructure by varying the pH of precursor solution via solution method. Zinc acetate dihydrate and sodium hydroxide were used as a precursor, which was refluxed at 90 °C for an hour. The pH of the precursor solution (zinc acetate di hydrate) was increased from 6 to 12 by the controlled addition of sodium hydroxide (NaOH). Morphology of ZnO nanorods markedly varies from sheet-like (at pH 6) to rod-like structure of zinc oxide (pH 10-12). Diffraction patterns match well with standard ZnO at all pH values. Crystallinity and nanostructures were confirmed by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) pattern, which indicates structure grew along [0 0 0 1] direction with an ideal lattice fringes distance 0.52 nm. FTIR spectroscopic measurement showed a standard peak of zinc oxide at 464 cm -1. Amount of H + and OH - ions are found key to the structure control of studied material, as discussed in the growth mechanism.

  19. Cytotoxicity of cultured macrophages exposed to antimicrobial zinc oxide (ZnO) coatings on nanoporous aluminum oxide membranes.

    PubMed

    Petrochenko, Peter E; Skoog, Shelby A; Zhang, Qin; Comstock, David J; Elam, Jeffrey W; Goering, Peter L; Narayan, Roger J

    2013-01-01

    Zinc oxide (ZnO) is a widely used commercial material that is finding use in wound healing applications due to its antimicrobial properties. Our study demonstrates a novel approach for coating ZnO with precise thickness control onto 20 nm and 100 nm pore diameter anodized aluminum oxide using atomic layer deposition (ALD). ZnO was deposited throughout the nanoporous structure of the anodized aluminum oxide membranes. An 8 nm-thick coating of ZnO, previously noted to have antimicrobial properties, was cytotoxic to cultured macrophages. After 48 h, ZnO-coated 20 nm and 100 nm pore anodized aluminum oxide significantly decreased cell viability by ≈65% and 54%, respectively, compared with cells grown on uncoated anodized aluminum oxide membranes and cells grown on tissue culture plates. Pore diameter (20-200 nm) did not influence cell viability.

  20. Aligned carbon nanotube, graphene and graphite oxide thin films via substrate-directed rapid interfacial deposition.

    PubMed

    D'Arcy, Julio M; Tran, Henry D; Stieg, Adam Z; Gimzewski, James K; Kaner, Richard B

    2012-05-21

    A procedure for depositing thin films of carbon nanostructures is described that overcomes the limitations typically associated with solution based methods. Transparent and conductively continuous carbon coatings can be grown on virtually any type of substrate within seconds. Interfacial surface tension gradients result in directional fluid flow and film spreading at the water/oil interface. Transparent films of carbon nanostructures are produced including aligned ropes of single-walled carbon nanotubes and assemblies of single sheets of chemically converted graphene and graphite oxide. Process scale-up, layer-by-layer deposition, and a simple method for coating non-activated hydrophobic surfaces are demonstrated.

  1. Oxide/Water Interfaces: How the Surface Chemistry Modifies the Electronic Energy Alignment

    NASA Astrophysics Data System (ADS)

    Sprik, Michiel

    2014-03-01

    The minimum of the d-electron conduction band of an aqueous transition metal oxide electrode is typically no more than a few 100 mV away from the standard hydrogen electrode (SHE). Because of this favourable alignment of the electronic energy levels (near) metallic transition metal oxides with partly filled d bands can be used as electrocatalysts while the compounds with finite electronic gap can be used as photocatalysts. However, because of their ionic character, transition metal-oxide surfaces also show amphiphilic acid-base activity. At low pH the basic sites are protonated and at high pH the acidic sites deprotonated creating an electrical double layer with corresponding surface potential. The alignment of the electronic energy levels, and by implication their redox activity, is therefore pH dependent. In fact, even in absence of protonic surface charge, the coordination with water molecules is already capable of shifting the electronic energy levels of the oxide by 1 eV or more. Computation of the electronic energies in transition metal oxide electrodes requires therefore a detailed modeling of their aqueous surface chemistry. The solvation energy of the proton is the common energy reference for both redox potentials on the SHE scale and acidity constants (pKa). Computation of the H+ solvation energy is therefore a key component in a unified treatment of redox and acid-base chemistry. In this talk we outline the Density Functional Theory based Molecular Dynamics (DFTMD) method we have developed for this purpose. The central tool of our approach is a method for reversible insertion of protons in the aqueous part of the DFTMD model system. As an illustration we discuss the application to the rutile TiO2/water and MnO2/water interface.

  2. The histopathology of rat lung following exposure to zinc oxide/hexachloroethane smoke or installation with zinc chloride followed by treatment with 70% oxygen

    SciTech Connect

    Brown, R.F.; Marrs, T.C.; Rice, P.; Masek, L.C. )

    1990-04-01

    The effects of inhaled zinc oxide/hexachloroethane smoke (11,580 mg x min/m3) and intratracheally instilled zinc chloride (2.5 mg/kg body weight) have been studied in rat lung. The effects of subsequent treatment with 70% oxygen have been studied after both procedures. Both the inhalation of the smoke and instillation of zinc chloride produced similar effects that included pulmonary edema, alveolitis and, at a later stage, some fibrosis. After zinc chloride instillation, the pathological changes largely spared the periphery of the lung, while following smoke inhalation they were more diffuse. Subsequent oxygen administration had little effect on the development or progression of the pathological changes.

  3. Electrochemistry of the Zinc-Silver Oxide System. Part 2: Practical Measurements of Energy Conversion Using Commercial Miniature Cells.

    ERIC Educational Resources Information Center

    Smith, Michael J.; Vincent, Colin A.

    1989-01-01

    Summarizes the quantitative relationships pertaining to the operation of electrochemical cells. Energy conversion efficiency, cycle efficiency, battery power, and energy/power density of two types of zinc-silver oxide cells are discussed. (YP)

  4. Carbon-Incorporated Amorphous Indium Zinc Oxide Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Parthiban, S.; Park, K.; Kim, H.-J.; Yang, S.; Kwon, J.-Y.

    2014-11-01

    We propose the use of amorphous-carbon indium zinc oxide (a-CIZO) as a channel material for thin-film transistor (TFT) fabrication. This study chose a carbon dopant as a carrier suppressor and strong oxygen binder in amorphous-indium zinc oxide (a-IZO) channel material. a-CIZO thin films were deposited using radiofrequency (RF) sputtering and postannealed at 150°C. X-ray diffraction and transmission electron microscopy analysis revealed that the film remained amorphous even after postannealing. The a-CIZO TFT postannealed at 150°C exhibited saturation field-effect mobility of 16.5 cm2 V-1 s-1 and on-off current ratio of ˜4.3 × 107.

  5. The electronic structure of co-sputtered zinc indium tin oxide thin films

    SciTech Connect

    Carreras, Paz; Antony, Aldrin; Bertomeu, Joan; Gutmann, Sebastian; Schlaf, Rudy

    2011-10-01

    Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses {approx}50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO{sub 2} films.

  6. Amorphous silicon-indium-zinc oxide semiconductor thin film transistors processed below 150 °C

    NASA Astrophysics Data System (ADS)

    Chong, Eugene; Chun, Yoon Soo; Lee, Sang Yeol

    2010-09-01

    Amorphous silicon-indium-zinc-oxide (a-SIZO) thin film transistor (TFT) was investigated with the process temperature below 150 °C. The a-SIZO TFT exhibited a field effect mobility of 21.6 cm2/V s and an on/off ratio of 107. The stabilities of a-SIZO TFT and indium-zinc-oxide (IZO) TFT were compared, and a-SIZO TFT showed 3.7 V shift for threshold voltage (Vth) compared to 10.8 V shift in IZO TFT after bias temperature stress. Si incorporation into IZO-system as a stabilizer, which was confirmed by x-ray photoelectron spectroscopy, resulted in small shift in Vth in a-SIZO TFT without deteriorating mobility of higher than 21.6 cm2/V s.

  7. Synthesis and dielectric properties of zinc oxide nanoparticles using a biotemplate

    SciTech Connect

    P, Sharmila P; Tharayil, Nisha J.

    2014-10-15

    Zinc Oxide nanoparticles are synthesized using DNA as capping agent. Zinc oxide nanoparticles are synthesized using DNA as a capping agent. Structural and morphological characterizations are done using SEM, FTIR and XRD. The particle size and lattice parameters are calculated from the diffraction data. The optical properties are studied using UV-Vis absorption spectroscopy and bandgap variation with temperature is determined. The dielectric property of nanoparticles is studied by varying temperature and frequency. The dielectric constant and dispersion parameters are found out. Method of Cole-Cole analysis is used to study the high temperature dispersion of relaxation time. The variation of both AC and DC conductivity are studied and activation energy calculated.

  8. Removal of Fluorides and Chlorides from Zinc Oxide Fumes by Microwave Sulfating Roasting

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Zhang, Libo; Chen, Guo; Peng, Jinhui; Zhou, Liexing; Yin, Shaohua; Liu, Chenhui

    2015-10-01

    Dechlorination and defluorination from zinc oxide dust by microwave sulfating roasting was investigated in this study. According to proposed reactions in the process, detailed experiments were systematically conducted to study the effect of roasting temperature, holding time, air and steam flow rates on the efficiency of the removal of F and Cl. The results show that 92.3% of F and 90.5% of Cl in the fume could be purified when the condition of the roasting temperature of 650 °C, holding time at 60 min, air flow of 300 L/h and steam flow of 8 ml/min was optimized. Our investigation indicates that microwave sulfating roasting could be a promising new way for the dechlorination and defluorination from zinc oxide dust.

  9. High-performance transistors based on zinc tin oxides by single spin-coating process.

    PubMed

    Zhao, Yunlong; Duan, Lian; Dong, Guifang; Zhang, Deqiang; Qiao, Juan; Wang, Liduo; Qiu, Yong

    2013-01-08

    Films of zinc tin oxide (ZTO), grown from solutions with zinc acetate dehydrate and tin(II) 2-ethylhexanoate dissolved in 2-methoxyethanol, have been used to fabricate thin-film transistors in combination with solution-processed aluminum oxide as the gate insulator. And the nonhomogeneity of the single-layer ZTO films, caused by both ZTO film-substrate interaction and surface crystallization, has been studied, which is essential to achieve high performance transistors. In the bottom-contact thin-film transistor based on a Sn-rich layer of ZTO, a high mobility of 78.9 cm(2) V(-1) s(-1) in the saturation region has been obtained, with an on-to-off current ratio of 10(5) and a threshold gate voltage of 1.6 V.

  10. Atmospheric-pressure glow plasma synthesis of plasmonic and photoluminescent zinc oxide nanocrystals

    NASA Astrophysics Data System (ADS)

    Bilik, N.; Greenberg, B. L.; Yang, J.; Aydil, E. S.; Kortshagen, U. R.

    2016-06-01

    In this paper, we present a large-volume (non-micro) atmospheric pressure glow plasma capable of rapid, large-scale zinc oxide nanocrystal synthesis and deposition (up to 400 μg/min), whereas in the majority of the literature, nanoparticles are synthesized using micro-scale or filamentary plasmas. The reactor is an RF dielectric barrier discharge with a non-uniform gap spacing. This design encourages pre-ionization during the plasma breakdown, making the discharge uniform over a large volume. The produced zinc oxide nanocrystals typically have diameters ranging from 4 to 15 nm and exhibit photoluminescence at ≈550 nm and localized surface plasmon resonance at ≈1900 cm-1 due to oxygen vacancies. The particle size can be tuned to a degree by varying the gas temperature and the precursor mixing ratio.

  11. Thermal stability of polyacetal/ethylene-octene copolymer/zinc oxide nanocomposites

    NASA Astrophysics Data System (ADS)

    Grigalovica, A.; Merijs Meri, R.; Zicans, J.; Ivanova, T.; Grabis, J.

    2013-12-01

    In this work we investigate binary blends of polyoxymethylene and ethylene octene copolymer (EOC) and their composites with nanostructured zinc oxide (ZnO). EOC content in the composites varies from 0 to 50 wt. %. The amount of ZnO filler in the composites is changed in the interval from 0 to 5 wt. %. Thermal properties of composites are investigated with thermogravimetric analysis and differential scanning calorimetry. It is observed that ZnO addition increases thermal stability of the investigated composites.

  12. Sulfur-Doped Zinc Oxide (ZnO) Nanostars: Synthesis and Simulation of Growth Mechanism

    DTIC Science & Technology

    2011-10-01

    characterization, and ab initio simulations of star-shaped hexagonal zinc oxide ( ZnO ) nanowires . The ZnO nanostructures were synthesized by a low...temperature hydrothermal growth method. The cross-section of the ZnO nanowires transformed from a hexagon to a hexagram when sulfur dopants from thiourea...emission of multiple longitudinal-optical (LO) phonons [1, 2, 4, 5]. Variously shaped ZnO nanowires and nanoparticles are routinely synthesized, and their

  13. Biomimetic zinc oxide replica with structural color using butterfly (Ideopsis similis) wings as templates.

    PubMed

    Zhang, Wang; Zhang, Di; Fan, Tongxiang; Ding, Jian; Gu, Jiajun; Guo, Qixin; Ogawa, Hiroshi

    2006-09-01

    Nano-structured colorful zinc oxide (ZnO) replicas were produced using the wings of the Ideopsis similis butterfly as templates. The ZnO replicas we obtained exhibit iridescence, which was clearly observed under an optical microscope (OM). Field emission scanning electron microscope analysis shows that all the microstructure details are maintained faithfully in the ZnO replica. A computer model was established to simulate the diffraction spectral results, which agreed well with the OM images.

  14. Fully transparent thin film transistors based on zinc oxide channel layer and molybdenum doped indium oxide electrodes

    NASA Astrophysics Data System (ADS)

    MÄ dzik, Mateusz; Elamurugu, Elangovan; Viegas, Jaime

    2016-03-01

    In this work we report the fabrication of thin film transistors (TFT) with zinc oxide channel and molybdenum doped indium oxide (IMO) electrodes, achieved by room temperature sputtering. A set of devices was fabricated, with varying channel width and length from 5μm to 300μm. Output and transfer characteristics were then extracted to study the performance of thin film transistors, namely threshold voltage and saturation current, enabling to determine optimal fabrication process parameters. Optical transmission in the UV-VIS-IR are also reported.

  15. Preparation of highly aligned silicon oxide nanowires with stable intensive photoluminescence

    NASA Astrophysics Data System (ADS)

    Duraia, El-Shazly M.; Mansurov, Z. A.; Tokmolden, S.; Beall, Gary W.

    2010-02-01

    In this work we report the successful formation of highly aligned vertical silicon oxide nanowires. The source of silicon was from the substrate itself without any additional source of silicon. X-ray measurement demonstrated that our nanowires are amorphous. Photoluminescence measurements were conducted through 18 months and indicated that there is a very good intensive emission peaks near the violet regions. The FTIR measurements indicated the existence of peaks at 463, 604, 795 and a wide peak at 1111 cm -1 and this can be attributed to Si-O-Si and Si-O stretching vibrations. We also report the formation of the octopus-like silicon oxide nanowires and the growth mechanism of these structures was discussed.

  16. Epitaxially aligned cuprous oxide nanowires for all-oxide, single-wire solar cells.

    PubMed

    Brittman, Sarah; Yoo, Youngdong; Dasgupta, Neil P; Kim, Si-in; Kim, Bongsoo; Yang, Peidong

    2014-08-13

    As a p-type semiconducting oxide that can absorb visible light, cuprous oxide (Cu2O) is an attractive material for solar energy conversion. This work introduces a high-temperature, vapor-phase synthesis that produces faceted Cu2O nanowires that grow epitaxially along the surface of a lattice-matched, single-crystal MgO substrate. Individual wires were then fabricated into single-wire, all-oxide diodes and solar cells using low-temperature atomic layer deposition (ALD) of TiO2 and ZnO films to form the heterojunction. The performance of devices made from pristine Cu2O wires and chlorine-exposed Cu2O wires was investigated under one-sun and laser illumination. These faceted wires allow the fabrication of well-controlled heterojunctions that can be used to investigate the interfacial properties of all-oxide solar cells.

  17. New CVD-based method for the growth of high-quality crystalline zinc oxide layers

    NASA Astrophysics Data System (ADS)

    Huber, Florian; Madel, Manfred; Reiser, Anton; Bauer, Sebastian; Thonke, Klaus

    2016-07-01

    High-quality zinc oxide (ZnO) layers were grown using a new chemical vapour deposition (CVD)-based low-cost growth method. The process is characterized by total simplicity, high growth rates, and cheap, less hazardous precursors. To produce elementary zinc vapour, methane (CH4) is used to reduce a ZnO powder. By re-oxidizing the zinc with pure oxygen, highly crystalline ZnO layers were grown on gallium nitride (GaN) layers and on sapphire substrates with an aluminum nitride (AlN) nucleation layer. Using simple CH4 as precursor has the big advantage of good controllability and the avoidance of highly toxic gases like nitrogen oxides. In photoluminescence (PL) measurements the samples show a strong near-band-edge emission and a sharp line width at 5 K. The good crystal quality has been confirmed in high resolution X-ray diffraction (HRXRD) measurements. This new growth method has great potential for industrial large-scale production of high-quality single crystal ZnO layers.

  18. Effects of morphology on photocatalytic performance of Zinc oxide nanostructures synthesized by rapid microwave irradiation methods

    NASA Astrophysics Data System (ADS)

    Kajbafvala, Amir; Ghorbani, Hamed; Paravar, Asieh; Samberg, Joshua P.; Kajbafvala, Ehsan; Sadrnezhaad, S. K.

    2012-04-01

    In this study, two different chemical solution methods were used to synthesize Zinc oxide nanostructures via a simple and fast microwave assisted method. Afterwards, the photocatalytic performances of the produced ZnO powders were investigated using methylene blue (MB) photodegradation with UV lamp irradiation. The obtained ZnO nanostructures showed spherical and flower-like morphologies. The average crystallite size of the flower-like and spherical nanostructures were determined to be about 55 nm and 28 nm, respectively. X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), room temperature photoluminescence (RT-PL) and UV-vis analysis were used for characterization of the synthesized ZnO powders. Using BET N2-adsorption technique, the specific surface area of the flower-like and spherical ZnO nanostructures were found to be 22.9 m2/gr and 98 m2/gr, respectively. Both morphologies show similar band gap values. Finally, our results depict that the efficiency of photocatalytic performance in the Zinc oxide nanostructures with spherical morphology is greater than that found in the flower-like Zinc oxide nanostructures as well as bulk ZnO.

  19. PEGylated silver doped zinc oxide nanoparticles as novel photosensitizers for photodynamic therapy against Leishmania.

    PubMed

    Nadhman, Akhtar; Nazir, Samina; Khan, Malik Ihsanullah; Arooj, Syeda; Bakhtiar, Muhammad; Shahnaz, Gul; Yasinzai, Masoom

    2014-12-01

    We describe daylight responsive silver (Ag) doped semiconductor nanoparticles of zinc oxide (DSNs) for photodynamic therapy (PDT) against Leishmania. The developed materials were characterized by X-ray diffraction analysis (XRD), Rutherford backscattering (RBS), diffused reflectance spectroscopy (DRS), and band-gap analysis. The Ag doped semiconductor nanoparticles of zinc oxide were PEGylated to enhance their biocompatibility. The DSNs demonstrated effective daylight response in the PDT of Leishmania protozoans, through the generation of reactive oxygen species (ROS) with a quantum yield of 0.13 by nondoped zinc oxide nanoparticles (NDSN) whereas 0.28 by DSNs. None of the nanoparticles have shown any antileishmanial activity in dark, confirming that only ROS produced in the daylight were involved in the killing of leishmanial cells. Furthermore, the synthesized nanoparticles were found biocompatible. Using reactive oxygen species scavengers, cell death was attributable mainly to 77-83% singlet oxygen and 18-27% hydroxyl radical. The nanoparticles caused permeability of the cell membrane, leading to the death of parasites. Further, the uptake of nanoparticles by Leishmania cells was confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). We believe that these DSNs are widely applicable for the PDT of leishmaniasis, cancers, and other infections due to daylight response.

  20. Novel biocompatible composite (Chitosan-zinc oxide nanoparticle): preparation, characterization and dye adsorption properties.

    PubMed

    Salehi, Raziyeh; Arami, Mokhtar; Mahmoodi, Niyaz Mohammad; Bahrami, Hajir; Khorramfar, Shooka

    2010-10-01

    In this paper, the preparation, characterization and dye adsorption properties of novel biocompatible composite (Chitosan-zinc oxide nanoparticle) (CS/n-ZnO) were investigated. Zinc oxide nanoparticles were immobilized onto Chitosan. Physical characteristics of CS/n-ZnO were studied using Fourier transform infra-red (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray spectroscopy (WDX). Two textile dyes, Direct Blue 78 (DB78) and Acid Black 26 (AB26), were used as model compounds. The effect of CS/n-ZnO doses, initial dye concentration, salt and pH were elucidated at 20+/-1 degrees C. The isotherm and kinetics of dye adsorption were studied. The presence of functional groups such as hydroxyl, amino and carbonyl groups were detected. Results showed zinc oxide nanoparticles were immobilized onto Chitosan. The data were evaluated for compliance with the Langmuir, Freundlich and Tempkin isotherm models. It was found that AB26 and DB78 followed with Langmuir and Tempkin isotherms, respectively. In addition, adsorption kinetics of both dyes was found to conform to pseudo-second order kinetics. Based on the data of present investigation, one could conclude that the CS/n-ZnO being a biocompatible, eco-friendly and low-cost adsorbent might be a suitable alternative for elimination of dyes from colored aqueous solutions.

  1. The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.

    PubMed

    Gerlach, D; Wimmer, M; Wilks, R G; Félix, R; Kronast, F; Ruske, F; Bär, M

    2014-12-21

    The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization.

  2. Influence of particle size of nano zinc oxide on the controlled delivery of Amoxicillin

    NASA Astrophysics Data System (ADS)

    Palanikumar, L.; Ramasamy, S.; Hariharan, G.; Balachandran, C.

    2013-10-01

    A great effort has been exerted to develop drug carriers aiming at satisfying the requirements, such as safety, greater efficiency, predictable therapeutic response, and prolonged release period. The present study aims at developing the use of zinc oxide nanoparticles as a carrier as a function of particle size for amoxicillin drug delivery system. The amoxicillin-loaded zinc oxide nanoparticles have a good antibacterial activity against infectious Gram-positive and Gram-negative bacteria. Zinc oxide nanoparticles have been prepared by wet chemical precipitation method varying the pH values. Particle size and morphology of the as-prepared ZnO powders are characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscope. Drug loading, in vitro drug release and antibacterial activity have been analyzed. Maximum zone of inhibition is observed for Staphylococcus epidermis. The results show that inhibitory efficacy of drug-loaded ZnO nanoparticles is very much dependent on its chosen concentration, drug loading, and size.

  3. Hybrid structure of biotemplate-zinc-tin oxide for better optical, morphological and photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Karpuraranjith, M.; Thambidurai, S.

    2017-03-01

    A new chitosan (as biotemplate)-zinc-tin oxide hybrid structure was successfully synthesized by a chemical precipitation method and annealed at 500 °C. We studied the structural changes, optical, thermal and photo catalytic properties. The chemical bonding of the Zn-O and Sn-O-Sn functional groups were confirmed by FT-IR absorption peaks appearing at 538 and 635 cm‑1. The different ratio of ZnO to SnO2 particles on the biotemplate matrix altered the morphology of the hybrids from an agglomerated state to a microcrystalline form confirmed by HR-SEM and TEM analysis. The formation of a Zn0.15Sn0.85O hybrid structure was observed in the visible light region, with an energy band gap of ∼3.19 eV and higher surface area of 98 m2 g‑1. The thermal property shows that CS-Zn0.15Sn0.85O has a higher thermal stability than a CS-Zn0.25Sn0.75O hybrid structure. The results demonstrate that the biotemplate-zinc-tin oxide hybrid structure has a reinforced effect compared to the other components. Therefore, a biotemplate-based zinc-tin oxide hybrid structure could be a promising material for better dye removal efficiency, which was obtained for ∼100 and 96% with MB and RY-15 dyes.

  4. Zinc supplementation decreases oxidative stress, incidence of infection, and generation of inflammatory cytokines in sickle cell disease patients.

    PubMed

    Bao, Bin; Prasad, Ananda S; Beck, Frances W J; Snell, Diane; Suneja, Anupam; Sarkar, Fazlul H; Doshi, Nimisha; Fitzgerald, James T; Swerdlow, Paul

    2008-08-01

    Zinc deficiency is common in adult sickle-cell disease (SCD) patients. We previously demonstrated that zinc supplementation to adult SCD patients decreased the incidences of infections and hospital admissions. We hypothesize that zinc supplementation improves T-helper cell function and decreases vascular endothelial cell activation, oxidative stress, and nuclear factor-kappa B (NF-kappaB)-DNA binding in mononuclear cells (MNCs) in SCD patients. To test this hypothesis, 36 SCD patients were recruited and randomly divided into 2 groups. One group (n = 18) received 25-mg zinc orally thrice a day for 3 months. The other group (n = 18) received placebo. The results indicate that the zinc-supplemented group had decreased incidence of infections compared with the placebo group. After zinc supplementation, red blood cell, hemoglobin (Hb), hematocrit, (Hct), plasma zinc, and antioxidant power increased; plasma nitrite and nitrate (NOx), lipid peroxidation products, DNA oxidation products, and soluble vascular cell adhesion molecule-1 decreased in the zinc-supplemented group, compared with the placebo group. Zinc-supplemented patients exhibited significant decreases in lipopolysaccharide-induced tumor necrosis factor-alpha (TNF-alpha) and IL-1beta mRNAs, and TNF-induced nuclear factor of kappaB-DNA binding in MNCs, compared with the placebo group. Ex vivo addition of zinc to MNCs isolated from the placebo subjects decreased TNF-alpha and IL-1beta mRNAs. Zinc supplementation also increased relative levels of IL-2 and IL-2Ralpha mRNAs in phytohemagglutinin-p-stimulated MNCs. These results suggest that zinc supplementation may be beneficial to SCD patients.

  5. Preventive effect of zinc against cadmium-induced oxidative stress in the rat testis.

    PubMed

    Amara, Salem; Abdelmelek, Hafedh; Garrel, Catherine; Guiraud, Pascale; Douki, Thierry; Ravanat, Jean-Luc; Favier, Alain; Sakly, Mohsen; Ben Rhouma, Khémais

    2008-04-01

    The aim of this study was to investigate the antioxidant role of zinc (Zn) in the Cd-exposed testes of Wistar rats. Subchronic exposure to Cd (CdCl(2), 40 mg/l, per os) for 30 days resulted in a significant reduction in growth rate (-11%) and relative weights of testes (-36%) and seminal vesicles (-80%). Treated rats displayed a decrease in testicular and plasma testosterone levels, respectively (-70%, P<0.05; -48%, P<0.05), epididymal sperm count (-22%, P<0.05), and spermatozoa motility (-35%, P<0.05). In contrast, Cd increased the malondialdehyde (+46%, P<0.05), metallothionein (+200%, P<0.05), and 8-oxodGuo concentrations (+71%, P<0.05) in the testis. In the gonad, Cd decreased the GPx (-30%, P<0.05), CAT (-32%, P<0.05), mitochondrial Mn-SOD (-34%, P<0.05), and cytosolic CuZn-SOD (-32%, P<0.05) activities. Zinc supplementation (ZnCl(2), 40 mg/l, per os) in the Cd-exposed rats restored the activities of GPx, CuZn-SOD, and Mn-SOD in the testes to the levels of the control group. Moreover, zinc administration was capable of reducing the elevated levels of malondialdehyde in the testis. Interestingly, zinc supplementation attenuated DNA oxidation induced by Cd in the gonad and restored the testosterone level and sperm count to the levels of the control group. Zinc administration minimized oxidative damage and reversed the impairment of spermatogenesis and testosterone production induced by Cd in the rat testis.

  6. Characterization of Zinc Oxide and Pentacene Thin Film Transistors for CMOS Inverters

    NASA Astrophysics Data System (ADS)

    Iechi, Hiroyuki; Watanabe, Yasuyuki; Yamauchi, Hiroshi; Kudo, Kazuhiro

    We fabricated both thin film transistors (TFTs) and diodes using zinc oxide (ZnO) and pentacene, and investigated their basic characteristics. We found that field-effect mobility is influenced by the interface state between the semiconductor and dielectric layers. Furthermore, the complementary metal oxide semiconductor (CMOS) inverter using a p-channel pentacene field-effect transistor (FET) and an n-channel ZnO FET showed a relatively high voltage gain (8 - 12) by optimizing the device structure. The hybrid complementary inverters described here are expected for application in flexible displays, radio frequency identification cards (RFID) tags, and others.

  7. Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations

    NASA Astrophysics Data System (ADS)

    Shirakawa, Shingo; Kobayashi, Takayuki; Matsushita, Yoshinao; Sakai, Takehisa; Suzuki, Hironori; Ozaki, Yuzo

    Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

  8. Acceptor conductivity in bulk zinc oxide (0001) crystals

    NASA Astrophysics Data System (ADS)

    Adekore, Bababunmi Tolu

    ZnO is a promising wide bandgap semiconductor. Its renowned and prominent properties as its bandgap of 3.37eV at 4.2K; its very high excitonic binding energy, 60meV; its high melting temperature, 2248K constitute the basis for the recently renewed and sustained scientific interests in the material. In addition to the foregoing, the availability of bulk substrates of industrially relevant sizes provides important opportunities such as homoepitaxial deposition of the material which is a technological asset in the production of efficient optoelectronic and electronic devices. The nemesis of wide bandgap materials cannot be more exemplified than in ZnO. The notorious limitation of asymmetric doping and the haunting plague of electrically active point defects dim the bright future of the material. In this case, the search for reliable and consistent acceptor conductivity in bulk substrates has been hitherto, unsuccessful. In the dissertation that now follows, our efforts have been concerted in the search for a reliable acceptor. We have carefully investigated the science of point defects in the material, especially those responsible for the high donor conductivity. We also investigated and herein report variety of techniques of introducing acceptors into the material. We employ the most relevant and informative characterization techniques in verifying both the intended conductivity and the response of intrinsic crystals to variation in temperature and strain. And finally we explain deviations, where they exist, from ideal acceptor characteristics. Our work on reliable acceptor has been articulated in four papers. The first establishing capacitance based methods of monitoring electrically active donor defects. The second investigates the nature of anion acceptors on the oxygen sublattice. A study similar to the preceding study was conducted for cation acceptors on the zinc sublattice and reported in the third paper. Finally, an analysis of the response of the crystal to

  9. Copper Zinc Cobalt Aluminium Chromium Hydroxycarbonates and Mixed Oxides

    NASA Astrophysics Data System (ADS)

    Morpurgo, Simone; Jacono, Mariano Lo; Porta, Piero

    1996-03-01

    Hydroxycarbonate precursors with different Cu/Zn/Co/Al/Cr atomic ratios were prepared by coprecipitation of the metal nitrates with a stoichiometric amount of NaHCO3under controlled conditions of temperature, stirring, and pH. Cu-Zn-Co-Al-Cr mixed oxides were obtained by decomposition of the precursors at different temperatures (623, 723, and 973 K in air). The characterization has been performed by X-ray powder diffraction (XRPD), diffuse reflectance spectroscopy in the UV-VIS-NIR region (DRS), thermal analysis (TGA/DTA), BET surface area determination, and measurements of magnetic susceptibility. The XRPD patterns show that the precursors are quasi-amorphous layered double hydroxides (LDHs or hydrotalcite-like materials with the general stoichiometric formula:MII6MIII2(OH)16CO3· 4H2O, whereMII= Cu, Zn, Co andMIII= Al, Cr) containing a variable amount of Cu2(OH)2CO3(malachite). The thermal decomposition of the precursors occurred through complete dehydration of the sample (up toT= 573 K) and further release of CO2(up toT= 773 K). The decomposition of Cu2(OH)2CO3occurred in a single step at about 653 K. The mixed oxides obtained by calcination of the precursors at 623 K were poorly crystalline materials. Crystalline oxide mixtures containing CuO, ZnO, and spinels as ZnCr2O4, ZnCo2O4, ZnAl2O4, and Co3O4in a solid solution were formed only at 973 K, after complete release of CO2.

  10. Synergistic toughening of composite fibres by self-alignment of reduced graphene oxide and carbon nanotubes

    PubMed Central

    Shin, Min Kyoon; Lee, Bommy; Kim, Shi Hyeong; Lee, Jae Ah; Spinks, Geoffrey M.; Gambhir, Sanjeev; Wallace, Gordon G.; Kozlov, Mikhail E.; Baughman, Ray H.; Kim, Seon Jeong

    2012-01-01

    The extraordinary properties of graphene and carbon nanotubes motivate the development of methods for their use in producing continuous, strong, tough fibres. Previous work has shown that the toughness of the carbon nanotube-reinforced polymer fibres exceeds that of previously known materials. Here we show that further increased toughness results from combining carbon nanotubes and reduced graphene oxide flakes in solution-spun polymer fibres. The gravimetric toughness approaches 1,000 J g−1, far exceeding spider dragline silk (165 J g−1) and Kevlar (78 J g−1). This toughness enhancement is consistent with the observed formation of an interconnected network of partially aligned reduced graphene oxide flakes and carbon nanotubes during solution spinning, which act to deflect cracks and allow energy-consuming polymer deformation. Toughness is sensitive to the volume ratio of the reduced graphene oxide flakes to the carbon nanotubes in the spinning solution and the degree of graphene oxidation. The hybrid fibres were sewable and weavable, and could be shaped into high-modulus helical springs. PMID:22337128

  11. Synergistic toughening of composite fibres by self-alignment of reduced graphene oxide and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Shin, Min Kyoon; Lee, Bommy; Kim, Shi Hyeong; Lee, Jae Ah; Spinks, Geoffrey M.; Gambhir, Sanjeev; Wallace, Gordon G.; Kozlov, Mikhail E.; Baughman, Ray H.; Kim, Seon Jeong

    2012-01-01

    The extraordinary properties of graphene and carbon nanotubes motivate the development of methods for their use in producing continuous, strong, tough fibres. Previous work has shown that the toughness of the carbon nanotube-reinforced polymer fibres exceeds that of previously known materials. Here we show that further increased toughness results from combining carbon nanotubes and reduced graphene oxide flakes in solution-spun polymer fibres. The gravimetric toughness approaches 1,000 J g-1, far exceeding spider dragline silk (165 J g-1) and Kevlar (78 J g-1). This toughness enhancement is consistent with the observed formation of an interconnected network of partially aligned reduced graphene oxide flakes and carbon nanotubes during solution spinning, which act to deflect cracks and allow energy-consuming polymer deformation. Toughness is sensitive to the volume ratio of the reduced graphene oxide flakes to the carbon nanotubes in the spinning solution and the degree of graphene oxidation. The hybrid fibres were sewable and weavable, and could be shaped into high-modulus helical springs.

  12. Synergistic toughening of composite fibres by self-alignment of reduced graphene oxide and carbon nanotubes.

    PubMed

    Shin, Min Kyoon; Lee, Bommy; Kim, Shi Hyeong; Lee, Jae Ah; Spinks, Geoffrey M; Gambhir, Sanjeev; Wallace, Gordon G; Kozlov, Mikhail E; Baughman, Ray H; Kim, Seon Jeong

    2012-01-31

    The extraordinary properties of graphene and carbon nanotubes motivate the development of methods for their use in producing continuous, strong, tough fibres. Previous work has shown that the toughness of the carbon nanotube-reinforced polymer fibres exceeds that of previously known materials. Here we show that further increased toughness results from combining carbon nanotubes and reduced graphene oxide flakes in solution-spun polymer fibres. The gravimetric toughness approaches 1,000 J g(-1), far exceeding spider dragline silk (165 J g(-1)) and Kevlar (78 J g(-1)). This toughness enhancement is consistent with the observed formation of an interconnected network of partially aligned reduced graphene oxide flakes and carbon nanotubes during solution spinning, which act to deflect cracks and allow energy-consuming polymer deformation. Toughness is sensitive to the volume ratio of the reduced graphene oxide flakes to the carbon nanotubes in the spinning solution and the degree of graphene oxidation. The hybrid fibres were sewable and weavable, and could be shaped into high-modulus helical springs.

  13. Toxicity to woodlice of zinc and lead oxides added to soil litter

    USGS Publications Warehouse

    Beyer, W.N.; Anderson, A.

    1985-01-01

    Previous studies have shown that high concentrations of metals in soil are associated with reductions in decomposer populations. We have here determined the relation between the concentrations of lead and zinc added as oxides to soil litter and the survival and reproduction of a decomposer population under controlled conditions. Laboratory populations of woodlice (Porcellio scaber Latr) were fed soil litter treated with lead or zinc at concentrations that ranged from 100 to 12,800 ppm. The survival of the adults, the maximum number of young alive, and the average number of young alive, were recorded over 64 weeks. Lead at 12,800 ppm and zinc at 1,600 ppm or more had statistically significant (p < 0.05) negative effects on the populations. These results agree with field observations suggesting that lead and zinc have reduced populations of decomposers in contaminated forest soil litter, and concentrations are similar to those reported to be associated with reductions in natural populations of decomposers. Poisoning of decomposers may disrupt nutrient cycling, reduce the numbers of invertebrates available to other wildlife for food, and contribute to the contamination of food chains.

  14. Effect of refluxing time on the morphology of pencil like zinc oxide nanostructures prepared by solution method

    NASA Astrophysics Data System (ADS)

    Wahab, Rizwan; Kim, Young-Soon; Shin, Hyung-Shik

    2010-10-01

    This paper presents the fabrication of pencil like zinc oxide nanorods by solution method using precursor zinc acetate di-hydrate (Zn(Ac)2.2H2O) and alkali sodium hydroxide (NaOH) at a very low refluxing temperature (75 °C) for different ageing/ refluxing (12 h, 24 h, 36 h, 48 h and 60 h) time intervals. The morphological observation was carried out by using Field Emission Scanning Electron Microscopy (FESEM). The FESEM revealed that as the aging/refluxing time increased, the size (length and diameter) of the zinc oxide nanorods also increased. Furthermore, the morphology and crystallinity of the products grown were also confirmed by Transmission Electron Microscopy (TEM), high-resolution TEM, and Selected Area Electron Diffraction (SAED) patterns, which indicated that grown pencils grew along a [0001] direction with an ideal lattice fringe distance of ˜0.52 nm. The optical properties of the grown pencil-like zinc oxide nanorods were characterized by using UV-vis spectroscopy. Strong absorbance peaks were observed at ˜375 nm to 378 nm, which is the characteristic peak for the wurtzite hexagonal phase of ZnO. The FTIR spectroscopic measurement showed a standard peak of zinc oxide in the range of 428 cm-1 to 520 cm-1. Additionally, on the basis of chemical and morphological analysis, we have also proposed a possible growth mechanism for pencillike zinc oxide nanostructures.

  15. Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide

    SciTech Connect

    Choi, Seung-Ha; Jung, Woo-Shik; Park, Jin-Hong

    2012-11-19

    In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide ({alpha}-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and R{sub s} measurement systems and HSC chemistry simulation tool. According to the experimental and simulated results, the diffused Ti atoms were easily oxidized due to its lowest oxidation free energy. Since oxygen atoms were decomposed from the {alpha}-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in {alpha}-IGZO was dramatically increased, contributing to the decrease of resistivity ({rho}) from 1.96 {Omega} cm (as-deposited {alpha}-IGZO) to 1.33 Multiplication-Sign 10{sup -3}{Omega} cm (350 Degree-Sign C annealed {alpha}-IGZO).

  16. High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

    SciTech Connect

    Lee, Ching-Ting Lin, Yung-Hao; Lin, Jhong-Ham

    2015-01-28

    Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance g{sub m} change, threshold voltage V{sub T} change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature.

  17. Copper and Zinc Oxide Composite Nanostructures for Solar Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Wu, Fei

    Solar energy is a clean and sustainable energy source to counter global environmental issues of rising atmospheric CO2 levels and depletion of natural resources. To extract useful work from solar energy, silicon-based photovoltaic devices are extensively used. The technological maturity and the high quality of silicon (Si) make it a material of choice. However limitations in Si exist, ranging from its indirect band gap to low light absorption coefficient and energy and capital intensive crystal growth schemes. Therefore, alternate materials that are earth-abundant, benign and simpler to process are needed for developing new platforms for solar energy harvesting applications. In this study, we explore oxides of copper (CuO and Cu2O) in a nanowire morphology as alternate energy harvesting materials. CuO has a bandgap of 1.2 eV whereas Cu2O has a bandgap of 2.1 eV making them ideally suited for absorbing solar radiation. First, we develop a method to synthesize vertical, single crystalline CuO and Cu2O nanowires of ~50 microm length and aspect ratios of ~200. CuO nanowire arrays are synthesized by thermal oxidation of Cu foils. Cu2O nanowire arrays are synthesized by thermal reduction of CuO nanowires. Next, surface engineering of these nanowires is achieved using atomic layer deposition (ALD) of ZnO. By depositing 1.4 nm of ZnO, a highly defective surface is produced on the CuO nanowires. These defects are capable of trapping charge as is evident through persistent photoconductivity measurements of ZnO coated CuO nanowires. The same nanowires serve as efficient photocatalysts reducing CO2 to CO with a yield of 1.98 mmol/g-cat/hr. Finally, to develop a robust platform for flexible solar cells, a protocol to transfer vertical CuO nanowires inside flexible polydimethylsiloxane (PDMS) is demonstrated. Embedded CuO nanowires-ZnO pn junctions show a VOC of 0.4 V and a JSC of 10.4 microA/cm2 under white light illumination of 5.7 mW/cm2. Thus, this research provides broad

  18. Room temperature deposition of zinc oxide thin films by rf-magnetron sputtering for application in solar cells

    NASA Astrophysics Data System (ADS)

    Sanal, K. C.; Trujillo, R. R.; Nair, P. K.; Nair, M. T. S.

    2016-09-01

    Recent reports indicate that thin films of oxides of zinc: ZnO, Zn(O,S), or Zn-Mg-O, could be a better buffer component than CdS to provide an adequate band alignment with orthorhombic tin sulphide in thin lm solar cells. Thin films of ZnO were grown by rf-magnetron sputtering on different substrates at room temperature. Thin films of ZnO obtained by different deposition methods show hexagonal crystal structure, usually with a preferential orientation of (002) crystallographic planes parallel to the substrate surface. However, in the present study XRD patterns indicate that thicker ZnO films on glass substrates have preferential growth of (103) planes, while that on chemically deposited CdS or ZnS films preferential orientation of (002) planes persists. Bandgap of ZnO films increases from 3.2 eV to 3.4 eV when the chamber pressure used for deposition varies from 2.3 mTorr to 6 mTorr. ZnO films were incorporated in a solar cell structure stainless steel/SnS(cubic)/SnS(orthorhombic)/SnS(cubic)/CdS/ZnO/ZnO:Al. It showed open-circuit voltage of 0.318 V, short-circuit current density of 3.6 mA/cm2 and conversion efficiency of 0.82%.

  19. Deposition of zinc oxide photoelectrode using plasma enhanced chemical vapor deposition for dye-sensitized solar cells.

    PubMed

    Lee, Su Young; Kim, Sang Ho

    2014-12-01

    We investigated the characteristics of zinc oxide (ZnO) photoelectrodes grown by plasma enhanced chemical vapor deposition. ZnO has many advantages, such as high binding energy, breakdown strength, cohesion, hardness, and electron mobility. On the F-doped SnO2 (FTO) electrode, we deposited ZnO as a function of thickness, and we examined the thickness effect on the I-V, fill factor, open-circuit voltage, short-circuit current density, and especially the power conversion efficiency of the built in dye-sensitized solar cell. To study the thickness effect on the conduction and recombination of electrons in the ZnO electrode, we analyzed the alignment of grains, crystallinity, impedance, and cyclic I-V properties. The thickness of ZnO changed the electron diffusion length and recombination time. As a result, the maximum power conversion efficiency of 2.63% was obtained with a moderately thick (8.06 μm) ZnO.

  20. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis

    PubMed Central

    Gutknecht, Toni; Gustafsson, Anna; Forsgren, Christer; Ekberg, Christian; Steenari, Britt-Marie

    2015-01-01

    Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production. PMID:26421313

  1. Production of zinc and manganese oxide particles by pyrolysis of alkaline and Zn-C battery waste.

    PubMed

    Ebin, Burçak; Petranikova, Martina; Steenari, Britt-Marie; Ekberg, Christian

    2016-05-01

    Production of zinc and manganese oxide particles from alkaline and zinc-carbon battery black mass was studied by a pyrolysis process at 850-950°C with various residence times under 1L/minN2(g) flow rate conditions without using any additive. The particular and chemical properties of the battery waste were characterized to investigate the possible reactions and effects on the properties of the reaction products. The thermodynamics of the pyrolysis process were studied using the HSC Chemistry 5.11 software. The carbothermic reduction reaction of battery black mass takes place and makes it possible to produce fine zinc particles by a rapid condensation, after the evaporation of zinc from a pyrolysis batch. The amount of zinc that can be separated from the black mass is increased by both pyrolysis temperature and residence time. Zinc recovery of 97% was achieved at 950°C and 1h residence time using the proposed alkaline battery recycling process. The pyrolysis residue is mainly MnO powder with a low amount of zinc, iron and potassium impurities and has an average particle size of 2.9μm. The obtained zinc particles have an average particle size of about 860nm and consist of hexagonal crystals around 110nm in size. The morphology of the zinc particles changes from a hexagonal shape to s spherical morphology by elevating the pyrolysis temperature.

  2. Proteus mirabilis alleviates zinc toxicity by preventing oxidative stress in maize (Zea mays) plants.

    PubMed

    Islam, Faisal; Yasmeen, Tahira; Riaz, Muhammad; Arif, Muhammad Saleem; Ali, Shafaqat; Raza, Syed Hammad

    2014-12-01

    Plant-associated bacteria can have beneficial effects on the growth and health of their host. However, the role of plant growth promoting bacteria (PGPR), under metal stress, has not been widely investigated. The present study investigated the possible mandatory role of plant growth promoting rhizobacteria in protecting plants from zinc (Zn) toxicity. The exposure of maize plants to 50µM zinc inhibited biomass production, decreased chlorophyll, total soluble protein and strongly increased accumulation of Zn in both root and shoot. Similarly, Zn enhanced hydrogen peroxide, electrolyte leakage and lipid peroxidation as indicated by malondaldehyde accumulation. Pre-soaking with novel Zn tolerant bacterial strain Proteus mirabilis (ZK1) isolated zinc (Zn) contaminated soil, alleviated the negative effect of Zn on growth and led to a decrease in oxidative injuries caused by Zn. Furthermore, strain ZK1 significantly enhanced the activities of catalase, guaiacol peroxidase, superoxide dismutase and ascorbic acid but lowered the Proline accumulation in Zn stressed plants. The results suggested that the inoculation of Zea mays plants with P. mirabilis during an earlier growth period could be related to its plant growth promoting activities and avoidance of cumulative damage upon exposure to Zn, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity.

  3. Pencil-like zinc oxide micro/nano-scale structures: Hydrothermal synthesis, optical and photocatalytic properties

    SciTech Connect

    Moulahi, A.; Sediri, F.

    2013-10-15

    Graphical abstract: - Highlights: • Zinc oxide micro/nanopencils have been synthesized hydrothermally. • Photocatalytic activity has been evaluated by the degradation of methylene blue under UV light irradiation. • ZnO nanopencils exhibit much higher photocatalytic activity than the commercial ZnO. - Abstract: Zinc oxide micro/nanopencils have been successfully synthesized by hydrothermal process using zinc acetate and diamines as structure-directing agents. The morphology, the structure, the crystallinity and the composition of the materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The optical properties of synthesized ZnO were investigated by UV–vis spectroscopy. The photocatalytic activity of the material has been evaluated by the degradation of methylene blue under UV irradiation. As a result, after the lapse of 150 min, around 82% bleaching was observed, with ZnO nanopencils yielding more photodegradation compared to that of commercial ZnO (61%)

  4. Reduced Staphylococcus aureus proliferation and biofilm formation on zinc oxide nanoparticle PVC composite surfaces.

    PubMed

    Seil, Justin T; Webster, Thomas J

    2011-06-01

    Conventional particulate zinc oxide (ZnO) is a known antibacterial agent. Studies have shown that reducing the size of ZnO particles to nanoscale dimensions further enhances their antibacterial properties. Polymers, like all biomaterials, run the risk of harboring bacteria which may produce an antibiotic-resistant biofilm. The addition of ZnO nanoparticles to form a polymer composite material may thus reduce undesirable bacteria activity. The purpose of the present in vitro study was to investigate the antibacterial properties of ZnO nanoparticles when incorporated into a traditional polymeric biomaterial. For this purpose, Staphylococcus aureus were seeded at a known cell density onto coverslips coated with a film of polyvinyl chloride (PVC) with varying concentrations of ZnO nanoparticles. Samples were cultured for 24 or 72 h. Methods of analysis, including optical density readings and crystal violet staining, indicated a reduced presence of a biofilm on ZnO nanoparticle polymer composites compared to pure polymer controls. Live/dead bacteria assays provided images to confirm the reduced presence of active bacteria on samples with zinc oxide nanoparticles. Conditioning of the cell culture medium by the composites was also investigated by measuring concentrations of elemental zinc (Zn(2+)) and bacteria growth in the presence of conditioned medium. This study demonstrated that the development of ZnO polymer composites may improve biomaterial effectiveness for numerous applications, such as endotracheal tubes, catheter and implanted biomaterials, which are prone to bacterial infection.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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 Mn2+ 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.

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

    SciTech Connect

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

    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.

  7. Morphological impact of zinc oxide layers on the device performance in thin-film transistors.

    PubMed

    Faber, Hendrik; Klaumünzer, Martin; Voigt, Michael; Galli, Diana; Vieweg, Benito F; Peukert, Wolfgang; Spiecker, Erdmann; Halik, Marcus

    2011-03-01

    Zinc oxide thin-films are prepared either by spin coating of an ethanolic dispersion of nanoparticles (NP, diameter 5 nm) or by spray pyrolysis of a zinc acetate dihydrate precursor. High-resolution electron microscopy studies reveal a monolayer of particles for the low temperature spin coating approach and larger crystalline domains of more than 30 nm for the spray pyrolysis technique. Thin-film transistor devices (TFTs) based on spray pyrolysis films exhibit higher electron mobilities of up to 24 cm2 V(-1) s(-1) compared to 0.6 cm2 V(-1) s(-1) for NP based TFTs. These observations were dedicated to a reduced number of grain boundaries within the transistor channel.

  8. Preparation, characterization and properties of novel covalently surface-functionalized zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Sato, Moriyuki; Harada, Hajime; Morito, Shigekazu; Fujita, Yasuhisa; Shimosaki, Shunsuke; Urano, Takeshi; Nakamura, Morihiko

    2010-05-01

    Novel covalently surface-modified zinc oxide (ZnO) nanoparticles (NP) (ZHIE) were successfully prepared, which have organic chains composed of hydrophilic amide and urethane linkages, and terminal amino groups on the surfaces, using zinc acetate monohydrate. FTIR spectroscopy, X-ray analysis and TEM observation suggested that the resultant ZHIE NPs have the mean sizes of about 10 nm in diameters, the organic chains linking the amino groups in the terminals and wurtzite crystal structure. UV-vis absorption spectrum of the ZHIE NPs in methanol showed maximum absorption band at 348 nm, supporting the TEM observations. Photoluminescent spectrum measurements depicted that the ZHIE NPs show broad visible emission band on the basis of trapped-electron emission. Cytotoxicity and phagocytosis assays suggested that the ZHIE NPs are noncytotoxic, and the ZHIE-labeled zymosan particles derived by conjugation of the ZHIE NPs with zymosan are internalized into the cells and generate fluorescence based on the ZHIE NPs.

  9. Colloidal infrared reflective and transparent conductive aluminum-doped zinc oxide nanocrystals

    DOEpatents

    Buonsanti, Raffaella; Milliron, Delia J

    2015-02-24

    The present invention provides a method of preparing aluminum-doped zinc oxide (AZO) nanocrystals. In an exemplary embodiment, the method includes (1) injecting a precursor mixture of a zinc precursor, an aluminum precursor, an amine, and a fatty acid in a solution of a vicinal diol in a non-coordinating solvent, thereby resulting in a reaction mixture, (2) precipitating the nanocrystals from the reaction mixture, thereby resulting in a final precipitate, and (3) dissolving the final precipitate in an apolar solvent. The present invention also provides a dispersion. In an exemplary embodiment, the dispersion includes (1) nanocrystals that are well separated from each other, where the nanocrystals are coated with surfactants and (2) an apolar solvent where the nanocrystals are suspended in the apolar solvent. The present invention also provides a film. In an exemplary embodiment, the film includes (1) a substrate and (2) nanocrystals that are evenly distributed on the substrate.

  10. Effect of Supersaturation on the Growth of Zinc Oxide Nanostructured Films by Electrochemical Deposition

    SciTech Connect

    Illy, B.; Ingham, B; Ryan, M

    2010-01-01

    The changes in crystal growth habit of electrodeposited zinc oxide with zinc nitrate concentration are explained by changes in the levels of saturation at the electrode. Three growth regimes are found between 0.5 and 50 mM. For concentrations less than 2 mM, the growth is one-dimensional. Nanorods grow by screw dislocations from the outside inward, no coalescence is observed, and their surface shows pyramid-like features. For concentrations above 20 mM, the growth is two-dimensional. Large levels of supersaturation favor the nucleation on the low indexes faces and large sheets are observed. In the intermediate regime of growth, the growth is pseudo three-dimensional. Nanorods with a conical ends grow initially before coalescing and forming dense films.

  11. The piezoelectric effect on zinc oxide nano on polyimide substrate by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Idris, A. A. M.; Arsat, R.; Ahmad, M. K.

    2017-03-01

    This paper reports the effect of the deposition conditions crystal quality and film thickness of the Zinc Oxide (ZnO) film on the polyimide substrate. The ZnO film has been deposited by using the spray pyrolysis technique. This technique needs Zinc Nitrate Hexahydrate with the mixture of deionized water. At 350 °C, a higher c-axis preferred orientation at peak 0002 crystal orientation, which is critical for piezoelectric applications in ZnO thin films are obtained with the thickness of thin film is 300ηm. It also produces the 204.8 Hz of frequency which is higher than other frequency obtained by lower growth temperature.

  12. Chemical synthesis of zinc oxide nanorods for enhanced hydrogen gas sensing

    NASA Astrophysics Data System (ADS)

    Musarrat, Jabeen; Muhammad Azhar, Iqbal; R Vasant, Kumar; Mansoor, Ahmed; Muhammad Tayyeb, Javed

    2014-01-01

    Zinc oxide (ZnO) nanorods are prepared using equimolar solution of zinc nitrate ((Zn(NO3)2) and hexamethylenetetramine (C6H12N4) by the hydrothermal technique at 80 °C for 12 h. Epitaxial growth is explored by X-ray diffraction (XRD) patterns, revealing that the ZnO nanorods have a hexagonal (wurtzite) structure. Absorption spectra of ZnO are measured by UV—visible spectrometer. The surface morphology is investigated by field emission scanning electron microscopy (FESEM). The synthesized ZnO nanorods are used for detecting the 150 °C hydrogen gas with a concentration over 1000 ppm. The obtained results show a reversible response. The influence of operating temperature on hydrogen gas detecting characteristic of ZnO nanorods is also investigated.

  13. Al-doped zinc oxide nanocomposites with enhanced thermoelectric properties.

    PubMed

    Jood, Priyanka; Mehta, Rutvik J; Zhang, Yanliang; Peleckis, Germanas; Wang, Xiaolin; Siegel, Richard W; Borca-Tasciuc, Theo; Dou, Shi Xue; Ramanath, Ganpati

    2011-10-12

    ZnO is a promising high figure-of-merit (ZT) thermoelectric material for power harvesting from heat due to its high melting point, high electrical conductivity σ, and Seebeck coefficient α, but its practical use is limited by a high lattice thermal conductivity κ(L). Here, we report Al-containing ZnO nanocomposites with up to a factor of 20 lower κ(L) than non-nanostructured ZnO, while retaining bulklike α and σ. We show that enhanced phonon scattering promoted by Al-induced grain refinement and ZnAl(2)O(4) nanoprecipitates presages ultralow κ ∼ 2 Wm( -1) K(-1) at 1000 K. The high α∼ -300 μV K(-1) and high σ ∼ 1-10(4) Ω(-1 )m(-1) result from an offsetting of the nanostructuring-induced mobility decrease by high, and nondegenerate, carrier concentrations obtained via excitation from shallow Al donor states. The resultant ZT ∼ 0.44 at 1000 K is 50% higher than that for the best non-nanostructured counterpart material at the same temperature and holds promise for engineering advanced oxide-based high-ZT thermoelectrics for applications.

  14. In vitro toxicity of zinc oxide nanoparticles: a review

    NASA Astrophysics Data System (ADS)

    Pandurangan, Muthuraman; Kim, Doo Hwan

    2015-03-01

    The toxic effect of ZnO nanoparticles is due to their solubility. ZnO nanoparticles dissolve in the extracellular region, which in turn increases the intracellular [Zn2+] level. The mechanism for increased intracellular [Zn2+] level and ZnO nanoparticles dissolution in the medium is still unclear. Cytotoxicity, increased oxidative stress, increased intracellular [Ca2+] level, decreased mitochondrial membrane potential, and interleukin-8 productions occur in the BEAS-2B bronchial epithelial cells and A549 alveolar adenocarcinoma cells following the exposure of ZnO nanoparticles. Confluent C2C12 cells are more resistant to ZnO nanoparticles compared to the sparse monolayer. Loss of 3T3-L1 cell viability, membrane leakage, and morphological changes occurs due to exposure of ZnO nanoparticles. ZnO nanoparticle induces cytotoxicity and mitochondrial dysfunction in RKO colon carcinoma cells. The occurrence of apoptosis, increased ROS level, reduced mitochondrial activity and formation of tubular intracellular structures are reported following exposure of ZnO nanoparticles in skin cells. Macrophages, monocytes, and dendritic cells are affected by ZnO nanoparticles. In addition, genotoxicity is also induced. The present review summarizes the literature on in vitro toxicity of ZnO nanoparticles (10-100 nm) on various cell lines.

  15. Overexpression of methionine sulfoxide reductases A and B2 protects MOLT-4 cells against zinc-induced oxidative stress.

    PubMed

    Cabreiro, Filipe; Picot, Cĕdric R; Perichon, Martine; Friguet, Bertrand; Petropoulos, Isabelle

    2009-02-01

    Among the amino acids, methionine is the most susceptible to oxidation, and methionine sulfoxide can be catalytically reduced within proteins by methionine sulfoxide reductase A (MsrA) and B (MsrB). As one of the very few repair systems for oxidized proteins, MsrA and MsrB enzymes play a major role in protein homeostasis during aging and have also been involved in cellular defenses against oxidative stress, by scavenging reactive oxygen species. To elucidate the role of zinc on the Msr system, the effects of zinc treatment on control and stably overexpressing MsrA and MsrB2 MOLT-4 leukemia cells have been analyzed. Here we show that zinc treatment has a pro-antioxidant effect in MOLT-4 cells by inducing the transcription of metallothioneins and positively modulating the activity of the Msr enzymes. In contrast, due to its pro-oxidant effect, zinc also led to increased cell death, reactive oxygen species production, and protein damage. Our results indicate that overexpression of the Msr enzymes, due to their antioxidant properties, counteracts the pro-oxidant effects of zinc treatment, which lead to a cellular protection against protein oxidative damage and cell death, by reducing the production of reactive oxygen species.

  16. Self-Assembled Epitaxial Au–Oxide Vertically Aligned Nanocomposites for Nanoscale Metamaterials

    SciTech Connect

    Li, Leigang; Sun, Liuyang; Gomez-Diaz, Juan Sebastian; Hogan, Nicki L.; Lu, Ping; Khatkhatay, Fauzia; Zhang, Wenrui; Jian, Jie; Huang, Jijie; Su, Qing; Fan, Meng; Jacob, Clement; Li, Jin; Zhang, Xinghang; Jia, Quanxi; Sheldon, Matthew; Alù, Andrea; Li, Xiaoqin; Wang, Haiyan

    2016-05-17

    Metamaterials made of nanoscale inclusions or artificial unit cells exhibit exotic optical properties that do not exist in natural materials. Promising applications, such as super-resolution imaging, cloaking, hyperbolic propagation, and ultrafast phase velocities have been demonstrated based on mostly micrometer-scale metamaterials and few nanoscale metamaterials. To date, most metamaterials are created using costly and tedious fabrication techniques with limited paths toward reliable large-scale fabrication. In this work, we demonstrate the one-step direct growth of self-assembled epitaxial metal–oxide nanocomposites as a drastically different approach to fabricating large-area nanostructured metamaterials. Using pulsed laser deposition, we fabricated nanocomposite films with vertically aligned gold (Au) nanopillars (~20 nm in diameter) embedded in various oxide matrices with high epitaxial quality. Strong, broad absorption features in the measured absorbance spectrum are clear signatures of plasmon resonances of Au nanopillars. By tuning their densities on selected substrates, anisotropic optical properties are demonstrated via angular dependent and polarization resolved reflectivity measurements and reproduced by full-wave simulations and effective medium theory. Our model predicts exotic properties, such as zero permittivity responses and topological transitions. In conclusion, our studies suggest that these self-assembled metal–oxide nanostructures provide an exciting new material platform to control and enhance optical response at nanometer scales.

  17. Self-Assembled Epitaxial Au–Oxide Vertically Aligned Nanocomposites for Nanoscale Metamaterials

    DOE PAGES

    Li, Leigang; Sun, Liuyang; Gomez-Diaz, Juan Sebastian; ...

    2016-05-17

    Metamaterials made of nanoscale inclusions or artificial unit cells exhibit exotic optical properties that do not exist in natural materials. Promising applications, such as super-resolution imaging, cloaking, hyperbolic propagation, and ultrafast phase velocities have been demonstrated based on mostly micrometer-scale metamaterials and few nanoscale metamaterials. To date, most metamaterials are created using costly and tedious fabrication techniques with limited paths toward reliable large-scale fabrication. In this work, we demonstrate the one-step direct growth of self-assembled epitaxial metal–oxide nanocomposites as a drastically different approach to fabricating large-area nanostructured metamaterials. Using pulsed laser deposition, we fabricated nanocomposite films with vertically aligned goldmore » (Au) nanopillars (~20 nm in diameter) embedded in various oxide matrices with high epitaxial quality. Strong, broad absorption features in the measured absorbance spectrum are clear signatures of plasmon resonances of Au nanopillars. By tuning their densities on selected substrates, anisotropic optical properties are demonstrated via angular dependent and polarization resolved reflectivity measurements and reproduced by full-wave simulations and effective medium theory. Our model predicts exotic properties, such as zero permittivity responses and topological transitions. In conclusion, our studies suggest that these self-assembled metal–oxide nanostructures provide an exciting new material platform to control and enhance optical response at nanometer scales.« less

  18. Microwave accelerated synthesis of zinc oxide nanoplates and their enhanced photocatalytic activity under UV and solar illuminations

    NASA Astrophysics Data System (ADS)

    Anas, S.; Rahul, S.; Babitha, K. B.; Mangalaraja, R. V.; Ananthakumar, S.

    2015-11-01

    Photoactive zinc based nanoplates were developed through a rapid microwave synthesis. A low temperature thermolysis reaction in a surfactant medium was initially performed for producing microwave active zinc based polar precursors. Using these precursors, the zinc oxide nanopowder having platelet morphologies were prepared. The nanoplatelets exhibited random growth with non-polar (1 0 1) surface as the major growth plane. The structural and functional features of the resultant zinc oxide samples were monitored using XRD, FTIR, TEM and PL. The photocatalytic activities of the samples were investigated through the standard photoreduction kinetics using the methylene blue dye. The catalytic efficiencies of the samples were checked both under UV and sunlight. A comparative study was also performed with the standard TiO2 sample. The analyses revealed that the microwave derived zinc oxide have higher catalytic efficiency, than the standard titania samples, both under UV and sunlight illuminations. The unique nature of the zinc oxide non-polar surfaces can be attributed due to the presence of more active two dimensional open surfaces and the higher content of oxygen defect concentrations.

  19. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    SciTech Connect

    Zheng, Juanjuan; Zhang, Yu; Xu, Wentao; Luo, YunBo; Hao, Junran; Shen, Xiao Li; Yang, Xuan; Li, Xiaohong; Huang, Kunlun

    2013-04-15

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ{sub m}). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by

  20. Bio-Fabrication of zinc oxide nanoparticles using leaf extract of Parthenium hysterophorus L. and its size-dependent antifungal activity against plant fungal pathogens

    NASA Astrophysics Data System (ADS)

    Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2013-08-01

    The study reports the synthesis and characterization of zinc oxide nanoparticles from weed plant by a novel method. The aim of this work is to synthesize zinc oxide nanoparticles from Parthenium hysterophorus L. by inexpensive, ecofriendly and simple method. Highly stable, spherical and hexagonal zinc oxide nanoparticles were synthesized by using different concentrations of 50% and 25% parthenium leaf extracts. Both the concentrations of the leaf extract act as reducing and capping agent for conversion of nanoparticles. Formation of zinc oxide nanoparticles have been confirmed by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Fourier trans-form infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis with energy dispersive X-ray analysis (EDX). SEM, TEM and EDX analysis reveals that spherical and hexagonal zinc oxide nanoparticle sizes were 27 ± 5 nm and 84 ± 2 nm respectively and chemical composition of zinc oxide were present. We synthesized different sized zinc oxide nanoparticles and explored the size-dependent antifungal activity against plant fungal pathogens. Highest zone of inhibition was observed in 25 μg/ml of 27 ± 5 nm size zinc oxide nanoparticles against Aspergillus flavus and Aspergillus niger. Parthenium mediated zinc oxide nanoparticles were synthesized and proved to be good antifungal agents and environment friendly.

  1. Ultrasonic synthesis of two new zinc(II) bipyridine coordination polymers: New precursors for preparation of zinc(II) oxide nano-particles.

    PubMed

    Fard, Mohammad Jaafar Soltanian; Hayati, Payam; Firoozadeh, Azita; Janczak, Jan

    2017-03-01

    Nanoparticles of two zinc(II) coordination polymers (CPs), [Zn(μ-4,4'-bipy)Cl2]n (1) and [Zn(μ-4,4'-bipy)Br2]n (2) L=bpy=4,4'-bipyridine ligand, have been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) spectroscopy and elemental analyses. The single crystal X-ray data of compounds 1 and 2 imply that the Zn(+2) ions are four coordinated. Topological analysis shows that 1D coordination networks of 1 and 2 can be classified as underlying nets of topological types 2C1. Nanoparticles of zinc(II) oxide have been prepared by calcination of two different zinc (II) CPs at 450°C that were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and IR spectroscopy.

  2. Greener syntheses of metallic nanoparticles and zinc oxide nanopowders

    NASA Astrophysics Data System (ADS)

    Samson, Jacopo

    In recent years, nanotechnology and nanomaterials synthesis have attracted a great deal of attention in the scientific community. Nanomaterials display size and morphology-related optical properties that differ from their bulk counterparts and therefore can be used for many applications in different fields such as biomedicine, electronics, antibacterial agents, and energy. Attempts to fabricate different morphologies of metallic and metal oxide nanoparticles (NPs) have successfully yielded attractive nanostructures such as particles, rods, helices, combs, tetra-pods, and flowers, all displaying properties mainly related to their enhanced surface area and/or aspect ratios. Most of the above mentioned nanomaterials productions have employed harsh synthetic routes such as high temperatures, low pressures, and the use of costly equipments. Here we show how a greener approach to nanomaterials synthesis is feasible with both minimization of aqueous precursors, energy and employment of a multi-block heater for temperature control. We present in this thesis several methods for the preparation of NPs of several materials that focus on minimizing the environmental impact of the synthesis itself. First, we describe the use of the toroidal form of plasmid DNA as a rigid narrowly dispersed bio-polymeric nanocavity, which mold the formation of disc-shaped nanoparticles of several types of metals. This approach exploits several properties of plasmid DNA: (a) DNA affinity for metal cations, (b) toroidal plasmid DNA structures which are favored by metal ionic binding, and (c) the ability to vary plasmid size. Herein, we present a complementary synthetic method based on a kinetic approach wherein the plasmid DNA acts as a template to initiate and control the formation of Au and other metallic NPs by incubation at elevated temperatures. Also reported herein is a simple, scalable hydrothermal method to make ZnO NPs that exploits temperature to precisely control the range of pH values

  3. A new extraction method for the preparation of zinc oxide nanoparticles in aqueous two-phase systems

    NASA Astrophysics Data System (ADS)

    Voshkin, A. A.; Shkinev, V. M.; Zakhodyaeva, Yu. A.

    2017-02-01

    An extraction method was suggested for the preparation of differently shaped nano- and micrometer- sized zinc oxide particles at the interface boundary of aqueous two-phase systems based on polyethylene glycol (polyethylene oxide) and sodium sulfate using NaOH and aqueous ammonia as precipitating agents.

  4. Molybdenum as a contact material in zinc tin oxide thin film transistors

    SciTech Connect

    Hu, W.; Peterson, R. L.

    2014-05-12

    Amorphous oxide semiconductors are of increasing interest for a variety of thin film electronics applications. Here, the contact properties of different source/drain electrode materials to solution-processed amorphous zinc tin oxide (ZTO) thin-film transistors are studied using the transmission line method. The width-normalized contact resistance between ZTO and sputtered molybdenum is measured to be 8.7 Ω-cm, which is 10, 20, and 600 times smaller than that of gold/titanium, indium tin oxide, and evaporated molybdenum electrodes, respectively. The superior contact formed using sputtered molybdenum is due to a favorable work function lineup, an insulator-free interface, bombardment of ZTO during molybdenum sputtering, and trap-assisted tunneling. The transfer length of the sputtered molybdenum/ZTO contact is 0.34 μm, opening the door to future radio-frequency sub-micron molybdenum/ZTO thin film transistors.

  5. Nitric oxide inhibits the formation of zinc protoporphyrin IX and protoporphyrin IX.

    PubMed

    Wakamatsu, Jun-ichi; Hayashi, Nobutaka; Nishimura, Takanori; Hattori, Akihito

    2010-01-01

    The aim of this study was to elucidate the mechanism by which curing agents, especially nitrite, inhibit the formation of zinc protoporphyrin IX (ZPP) in dry-cured hams such as Parma ham. The oxidation-reduction potential of model solutions was increased by the addition of nitrite, but it was not clear whether the formation of ZPP is inhibited by the oxidizing property of nitrite. The effect of nitric oxide (NO) produced from nitrite on the formation of ZPP was examined. The amount of ZPP formed was decreased by the addition of NO donors. The amount of protoporphyrin IX (PPIX), which is the precursor of ZPP, was also decreased by the addition of NO donors. It is concluded that NO produced from nitrite inhibited the formation of PPIX and ZPP was therefore not formed in cured meat products with the addition of nitrite or nitrate.

  6. Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Wong, Ming Wah

    2008-01-01

    Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)zinc species also form very stable complexes with the radicals Me(2)NCS(2)(*) and Me(2)NCS(3)(*). Dissociation of the TMTD molecule at the S-S bond on reaction with the Zn(4)O(4) cluster is predicted to be strongly exothermic, in sharp contrast to the endothermic S-S bond dissociation of the free molecule. The same holds for tetramethylthiuram trisulfide (TMTT). Surprisingly, the resulting complexes contain Zn-S as well as S-O bonds. The Zn(4)O(4) nanocluster serves here as a model for bulk zinc oxide used as an activator in rubber vulcanization by sulfur. The further uptake of sulfur atoms by the various complexes from S(8) or TMTD with formation of species derived from the radical Me(2)NCS(3)(*) or the trithiocarbamate anion Me(2)NCS(3)(-) is endothermic for mono- and dinuclear zinc dithiocarbamate (dtc) complexes such as [Zn(dtc)(2)] and [Zn(2)(dtc)(4)], but exothermic in the case of polynuclear zinc oxide species containing bridging ligands as in [Zn(4)O(4)(mu-S(2)CNMe(2))] and [Zn(4)O(4)(mu-dtc)]. Therefore, zinc oxide as a polynuclear species is predicted to promote the formation of trisulfido complexes, which are generally assumed to serve as catalysts for the transfer of

  7. Identification and characterization of point defects in aluminum nitride and zinc oxide crystals

    NASA Astrophysics Data System (ADS)

    Evans, Sean M.

    Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) studies have been performed on single crystals of aluminum nitride (AlN) and zinc oxide (ZnO), two wide-band-gap semiconductors having the wurtzite crystal structure. These studies were used to characterize point defects in each material. In the first study in AlN, new EPR and ENDOR spectra were acquired from a deep donor. Although observed in as-grown crystals, exposure to x rays significantly increased the concentration of this center. ENDOR identified a strong hyperfine interaction with one aluminum neighbor along the c axis and weaker equivalent hyperfine interactions with three additional aluminum neighbors in the basal plane. These aluminum interactions indicate that the responsible center was located at a nitrogen site. The observed paramagnetic defect is either an oxygen substituting for nitrogen or a nitrogen vacancy. An analysis of the hyperfine data suggests that substitutional oxygen is the most likely candidate. The second point defect studied in AlN was silicon substituting for aluminum. Silicon is a shallow donor in AlN, and its neutral charge state is paramagnetic. Two samples containing silicon were studied. Only one of the samples was intentionally doped with silicon. The silicon-related EPR signals from these two samples had different behaviors. The signal from the doped sample had behavior similar to that described in previous studies where the silicon was explained as a DX center. The undoped sample had behavior that was inconsistent with a DX center. In ZnO, EPR was used to monitor oxygen vacancies and zinc vacancies in a ZnO crystal irradiated near room temperature with 1.5 MeV electrons. Out-of-phase detection at 30 K greatly enhanced the EPR signals from these vacancies. Following the electron irradiation, but before illumination, Fe3+ ions and nonaxial singly ionized zinc vacancies were observed. Illumination with 325 nm laser light at low temperature

  8. Repression of sulfate assimilation is an adaptive response of yeast to the oxidative stress of zinc deficiency.

    PubMed

    Wu, Chang-Yi; Roje, Sanja; Sandoval, Francisco J; Bird, Amanda J; Winge, Dennis R; Eide, David J

    2009-10-02

    The Zap1 transcription factor is a central player in the response of yeast to changes in zinc status. Previous studies identified over 80 genes activated by Zap1 in zinc-limited cells. In this report, we identified 36 genes repressed in a zinc- and Zap1-responsive manner. As a result, we have identified a new mechanism of Zap1-mediated gene repression whereby transcription of the MET3, MET14, and MET16 genes is repressed in zinc-limited cells. These genes encode the first three enzymes of the sulfate assimilation pathway. We found that MET30, encoding a component of the SCF(Met30) ubiquitin ligase, is a direct Zap1 target gene. MET30 expression is increased in zinc-limited cells, and this leads to degradation of Met4, a transcription factor responsible for MET3, MET14, and MET16 expression. Thus, Zap1 is responsible for a decrease in sulfate assimilation in zinc-limited cells. We further show that cells that are unable to down-regulate sulfate assimilation under zinc deficiency experience increased oxidative stress. This increased oxidative stress is associated with an increase in the NADP(+)/NADPH ratio and may result from a decrease in NADPH-dependent antioxidant activities. These studies have led to new insights into how cells adapt to nutrient-limiting growth conditions.

  9. Effect of carbamide peroxide and hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings.

    PubMed

    Rostein, I; Cohenca, N; Mor, C; Moshonov, J; Stabholz, A

    1995-12-01

    The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings was tested. Ninety IRM samples were treated with either 10% carbamide peroxide, 10% hydrogen peroxide or phosphate buffer which served as control. Treatment consisted of placing the samples in a dry incubator at 37 degrees C for 1, 3 or 7 days. At each time point, the samples were removed from the test solutions, dried and prepared for surface scanning electron microscopy and energy dispersive spectrometric analysis. After 3 days, 10% carbamide peroxide significantly reduced the zinc oxide levels as compared to the 10% hydrogen peroxide group (<0.01) and the controls (p<0.01). 10% hydrogen peroxide reduced the zinc oxide levels similarly to the control. No significant changes in the zinc oxide levels were found between 3 and 7 days in any of the groups tested. Microscopy examination of the carbamide peroxide group revealed granular surface with well defined crystalline areas. In the hydrogen peroxide group, numerous cracks with multiple sun burst-like areas were found. At the macroscopic level, the samples of this group appeared cracked and more swollen, as compared to controls and samples treated with carbamide peroxide. In conclusion, both 10% carbamide peroxide and 10% hydrogen peroxide altered the surface morphology and the zinc oxide levels of IRM fillings, but their modes of action differed.

  10. Ultrasound irradiation based in-situ synthesis of star-like Tragacanth gum/zinc oxide nanoparticles on cotton fabric.

    PubMed

    Ghayempour, Soraya; Montazer, Majid

    2017-01-01

    Application of natural biopolymers for green and safe synthesis of zinc oxide nanoparticles on the textiles is a novel and interesting approach. The present study offers the use of natural biopolymer, Tragacanth gum, as the reducing, stabilizing and binding agent for in-situ synthesis of zinc oxide nanoparticles on the cotton fabric. Ultrasonic irradiation leads to clean and easy synthesis of zinc oxide nanoparticles in short-time at low-temperature. FESEM/EDX, XRD, FT-IR spectroscopy, DSC, photocatalytic activities and antimicrobial assay are used to characterize Tragacanth gum/zinc oxide nanoparticles coated cotton fabric. The analysis confirmed synthesis of star-like zinc oxide nanoparticles with hexagonal wurtzite structure on the cotton fabric with the average particle size of 62nm. The finished cotton fabric showed a good photocatalytic activity on degradation of methylene blue and 100% antimicrobial properties with inhibition zone of 3.3±0.1, 3.1±0.1 and 3.0±0.1mm against Staphylococcus aureus, Escherichia coli and Candida albicans.

  11. Stability of Indium Gallium Zinc Aluminum Oxide Thin-Film Transistors with Treatment Processes

    NASA Astrophysics Data System (ADS)

    Lin, Yung-Hao; Lee, Ching-Ting

    2017-02-01

    The indium-gallium-zinc-aluminum-oxide (IGZAO) channel layer of the bottom-gate-type thin-film transistors (TFTs) was deposited on indium tin oxide-coated glass substrates using a magnetron radio frequency co-sputtering system with dual targets of indium gallium zinc oxide and Al. The 3 s orbital of Al cations provided an extra transport pathway and widened the bottom of the conduction band, thus increasing the electron mobility in the IGZAO films. The Al-O bonds could sustain the stability of oxygen of the IGZAO films. The IGZAO TFTs were processed by O2 plasma and post-annealing treatments. Hysteresis analysis was carried out in order to study the stability of the resulting IGZAO TFTs, the positive bias temperature stress (PBTS) performance, and the hot carrier effect were also measured. For the IGZAO TFTs, the threshold voltage shift of the PBTS performance and the hot carrier effect were 0.1 V and 0.06 V, respectively. Overall, the IGZAO TFTs exhibited good stability in this study.

  12. Density Functional Theory Study of Atomic Layer Deposition of Zinc Oxide on Graphene

    NASA Astrophysics Data System (ADS)

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-07-01

    The dissociation of zinc ions (Zn2+) from vapor-phase zinc acetylacetonate, Zn(C5H7O2)2, or Zn(acac)2 and its adsorption onto graphene oxide via atomic layer deposition (ALD) were studied using a quantum mechanics approach. Density functional theory (DFT) was used to obtain an approximate solution to the Schrödinger equation. The graphene oxide cluster model was used to represent the surface of the graphene film after pre-oxidation. In this study, the geometries of reactants, transition states, and products were optimized using the B3LYB/6-31G** level of theory or higher. Furthermore, the relative energies of the various intermediates and products in the gas-phase radical mechanism were calculated at the B3LYP/6-311++G** and MP2/6-311 + G(2df,2p) levels of theory. Additionally, a molecular orbital (MO) analysis was performed for the products of the decomposition of the Zn(acac)2 complex to investigate the dissociation of Zn2+ and the subsequent adsorption of H atoms on the C5H7O2 cluster to form acetylacetonate enol. The reaction energies were calculated, and the reaction mechanism was accordingly proposed. A simulation of infrared (IR) properties was performed using the same approach to support the proposed mechanism via a complete explanation of bond forming and breaking during each reaction step.

  13. Synthesis, characterization and enhanced antimicrobial activity of reduced graphene oxide–zinc oxide nanocomposite

    NASA Astrophysics Data System (ADS)

    Singh Rajaura, Rajveer; Sharma, Vinay; Shrivastava Ronin, Rishabh; Gupta, Deepak K.; Srivastava, Subodh; Agrawal, Kailash; Vijay, Y. K.

    2017-02-01

    In this work, we report a simple and facile one-pot chemical approach of the decoration of uniform zinc oxide nanoparticles (ZnO NPs) on reduced graphene oxide (GO) and a study of its antimicrobial activity. The nanocomposite was fully characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). TEM and SEM images clearly indicated the presence of Graphene sheets decorated with uniformly sized zinc oxide nanoparticles. Further, as an application of rGO-ZnO nanocomposites, their superior antibacterial activity was demonstrated on the Escherichia coli MTCC40 bacterial strain, using the standard disk diffusion method. This clearly showed that rGO-ZnO nanocomposites exhibited more pronounced antibacterial activity than rGO alone. This feature was revealed to be due to increased biocompatibility of PEGylated rGO-ZnO nanocomposites. In conclusion, the as-synthesized nanocomposite showed excellent antibacterial activity and has great potential for biomedical application.

  14. Density Functional Theory Study of Atomic Layer Deposition of Zinc Oxide on Graphene.

    PubMed

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-12-01

    The dissociation of zinc ions (Zn(2+)) from vapor-phase zinc acetylacetonate, Zn(C5H7O2)2, or Zn(acac)2 and its adsorption onto graphene oxide via atomic layer deposition (ALD) were studied using a quantum mechanics approach. Density functional theory (DFT) was used to obtain an approximate solution to the Schrödinger equation. The graphene oxide cluster model was used to represent the surface of the graphene film after pre-oxidation. In this study, the geometries of reactants, transition states, and products were optimized using the B3LYB/6-31G** level of theory or higher. Furthermore, the relative energies of the various intermediates and products in the gas-phase radical mechanism were calculated at the B3LYP/6-311++G** and MP2/6-311 + G(2df,2p) levels of theory. Additionally, a molecular orbital (MO) analysis was performed for the products of the decomposition of the Zn(acac)2 complex to investigate the dissociation of Zn(2+) and the subsequent adsorption of H atoms on the C5H7O2 cluster to form acetylacetonate enol. The reaction energies were calculated, and the reaction mechanism was accordingly proposed. A simulation of infrared (IR) properties was performed using the same approach to support the proposed mechanism via a complete explanation of bond forming and breaking during each reaction step.

  15. Solid lipid nanoparticles: a possible vehicle for zinc oxide and octocrylene.

    PubMed

    Berkman, M S; Yazan, Y

    2012-03-01

    An efficient sunscreen formulation shows good absorption in the relevant UV range. Efficacy also means that the UV absorber must be easily incorporated in any kind of formulation. In this study, a chemical absorber, octocrylene, and one of the most important physical blockers, zinc oxide, could be successfully incorporated into Solid Lipid Nanoparticle (SLN) systems which themselves have UV blocking potential similar to physical sunscreens, and remained stable for a period of 360 days while providing UVA and UVB protection. Crystalline structure related to the chemical nature of the solid lipid is a key factor to decide whether a sunscreening agent will be expelled or incorporated in the long-term and for a controlled optimization of active ingredient incorporation and loading, intensive characterization of the physical state of the lipid particles was highly essential. Thus, FT-IR, NMR, XRD and DSC analyses were performed and the results did not indicate stability problems. pH values of the SLN systems were found to be between 5.4-5.9 in all formulations which may be buffered by the skin. Transpore test results proved the UV blocking potential of the SLNs with not any active ingredient and the synergistic effects by the incorporation of molecular sunscreens. Therefore, concentration of molecular sunscreens in the formulations was decreased to 0.6%. UVA and UVB screening potentials of octocrylene and zinc oxide formulations were compared in the 290-400 nm wavelength region. Zinc oxide loaded SLN suspensions were found to be more effective in the UVA region while octocrylene loaded ones performed better in the UVB region.

  16. In-vitro antibacterial study of zinc oxide nanostructures on Streptococcus sobrinus

    NASA Astrophysics Data System (ADS)

    Bakhori, Siti Khadijah Mohd; Mahmud, Shahrom; Ann, Ling Chuo; Sirelkhatim, Amna; Hasan, Habsah; Mohamad, Dasmawati; Masudi, Sam'an Malik; Seeni, Azman; Rahman, Rosliza Abd

    2014-10-01

    Zinc oxide nanostructures were prepared using a pilot plant of zinc oxide boiling furnace. Generally, it produced two types of nanostructures different in morphology; one is rod-like shaped (ZnO-1) and a plate-like shape (ZnO-2). The properties of ZnO were studied by structural, optical and morphological using XRD, PL and FESEM respectively. The XRD patterns confirmed the wurtzite structures of ZnO with the calculated crystallite size of 41 nm (ZnO-1) and 42 nm (ZnO-2) using Scherrer formula. The NBE peaks were determined by photoluminescence spectra which reveal peak at 3.25 eV and 3.23 eV for ZnO-1 and ZnO-2 respectively. Prior to that, the morphologies for both ZnO-1 and ZnO-2 were demonstrated from FESEM micrographs. Subsequently the antibacterial study was conducted using in-vitro broth dilution technique towards a gram positive bacterium Streptococcus sobrinus (ATCC 33478) to investigate the level of antibacterial effect of zinc oxide nanostructures as antibacterial agent. Gradual increment of ZnO concentrations from 10-20 mM affected the inhibition level after twenty four hours of incubation. In conjunction with concentration increment of ZnO, the percentage inhibition towards Streptococcus sobrinus was also increased accordingly. The highest inhibition occurred at 20 mM of ZnO-1 and ZnO-2 for 98% and 77% respectively. It showed that ZnO has good properties as antibacterial agent and relevancy with data presented by XRD, PL and FESEM were determined.

  17. An Alignment Medium for Measuring Residual Dipolar Couplings in Pure DMSO: Liquid Crystals from Graphene Oxide Grafted with Polymer Brushes.

    PubMed

    Zong, Wen; Li, Gao-Wei; Cao, Jiang-Ming; Lei, Xinxiang; Hu, Mao-Lin; Sun, Han; Griesinger, Christian; Tan, Ren Xiang

    2016-03-07

    Residual dipolar couplings (RDCs) have attracted attention in light of their great impact on the structural elucidation of organic molecules. However, the effectiveness of RDC measurements is limited by the shortage of alignment media compatible with widely used organic solvents, such as DMSO. Herein, we present the first liquid crystal (LC) based alignment medium that is compatible with pure DMSO, thus enabling RDC measurements of polar and intermediate polarity molecules. The liquid crystals were obtained by grafting polymer brushes onto graphene oxide (GO) using free radical polymerization. The resulting new medium offers several advantages, such as absence of background signals, narrow line shapes, and tunable alignment. Importantly, this medium is compatible with π-conjugated molecules. Moreover, sonication-induced fragmentation can reduce the size of GO sheets. The resulting anisotropic medium has moderate alignment strength, which is a prerequisite for an accurate RDC measurement.

  18. Preparation of surface modified zinc oxide nanoparticle with high capacity dye removal ability

    SciTech Connect

    Mahmoodi, Niyaz Mohammad; Najafi, Farhood

    2012-07-15

    Highlights: ► Amine-functionalized zinc oxide nanoparticle (AFZON) was synthesized. ► Isotherm and kinetics data followed Langmuir isotherm and pseudo-second order kinetic model, respectively. ► Q{sub 0} of ZON for AB25, DR23 and DR31 was 20, 12 and 15 mg/g, respectively. ► Q{sub 0} of AFZON for AB25, DR23 and DR31 was 1250, 1000 and 1429 mg/g, respectively. ► AFZON was regenerated at pH 12. -- Abstract: In this paper, the surface modification of zinc oxide nanoparticle (ZON) by amine functionalization was studied to prepare high capacity adsorbent. Dye removal ability of amine-functionalized zinc oxide nanoparticle (AFZON) and zinc oxide nanoparticle (ZON) was also investigated. The physical characteristics of AFZON were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Acid Blue 25 (AB25), Direct Red 23 (DR23) and Direct Red 31 (DR31) were used as model compounds. The effect of operational parameters such as dye concentration, adsorbent dosage, pH and salt on dye removal was evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q{sub 0}) was 20 mg/g AB25, 12 mg/g DR23 and 15 mg/g DR31 for ZON and 1250 mg/g AB25, 1000 mg/g DR23 and 1429 mg/g DR31 for AFZON. It was found that dye adsorption followed Langmuir isotherm. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% AB25, 86% for DR23 and 90% for DR31 were achieved in aqueous solution at pH 12. Based on the data of the present investigation, it can be concluded that the AFZON being an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions.

  19. The reduction and distillation of isotopically enriched zinc oxides under high vacuum conditions

    NASA Astrophysics Data System (ADS)

    Marcus, C.; Zevenbergen, L. A.

    1999-12-01

    Historically, enriched zinc (Zn) metal was produced at the Oak Ridge National Laboratory's Isotope Enrichment Facility (IEF) by either electrodeposition, followed by melting to produce a metal ingot, or purified by hydrogen reduction and distillation at atmospheric pressure in a tube furnace as a prelude to electroplating. Electroplated material was generally poor in quality, and losses were high during subsequent melting. Adapting the distillation purifying technique as an ultimate means of recovery of Zn metal proved to be difficult and inefficient. To resolve these problems, the well-established vacuum reduction/distillation process was adapted for the conversion of Zn oxide to metal.

  20. Rapid synthesis of zinc oxide nanoforest: use of microwave and forced seeding

    NASA Astrophysics Data System (ADS)

    Ghosh, S.; Chakraborty, J.

    2016-12-01

    A rapid synthesis technique has been developed for zinc oxide (ZnO) nanoforest using microwave assisted hydrothermal method. This microwave assisted process takes less than 4 h whereas conventional hydrothermal synthesis takes 25 h to fabricate nanoforest of comparable dimensions. The simple dipping technique for secondary seeding on the primary nanorods has been studied and it has been shown that such seeding would take at least an hour. A ‘forced seeding’ technique has been developed which reduces the seeding time drastically. The microwave assisted branch growth occurs at a speed of 10 nm min-1 which is 10 fold faster than that of hydrothermal method.

  1. Cu-doped zinc oxide and its polythiophene composites: preparation and antibacterial properties.

    PubMed

    Ma, Ge; Liang, Xiaoxi; Li, Liangchao; Qiao, Ru; Jiang, Donghua; Ding, Yan; Chen, Haifeng

    2014-04-01

    Cu-doped zinc oxide and its polythiophene nanocomposites were prepared by the Sol-Gel and in situ polymerization methods, respectively. The structures, morphologies and compositions of the samples were characterized. The antibacterial properties of the samples on three kinds of strains were determined by using powder inhibition zones, minimum inhibitory concentrations and minimal bactericidal concentrations. The study confirmed that the antibacterial activities of the composites were better than those of their each component. The antibacterial mechanisms of the samples were discussed further.

  2. Amorphous indium zinc oxide thin film transistors with poly-4-vinylphenol gate dielectric layers

    NASA Astrophysics Data System (ADS)

    Pu, Haifeng; Li, Guifeng; Feng, Jiahan; Liu, Baoying; Zhang, Qun

    2011-09-01

    Thin film transistors (TFTs) with amorphous indium zinc oxide (a-IZO) as channel layers and poly-4-vinylphenol as dielectric layers were fabricated. Transmission curves show that the double-layer structure of the a-IZO layer and the poly-4-vinylphenol layer exhibits the antireflection effect. It was found that post heat-treatment at relatively low temperature will improve the electrical performance of the transistors. TFT devices with saturation mobility of 25.4 cm2 V-1 s-1, threshold voltage of 4.0 V, subthreshold swing value of 0.88 V/decade and current on/off ratio of 106 were obtained.

  3. Amorphous indium-gallium-zinc-oxide visible-light phototransistor with a polymeric light absorption layer

    NASA Astrophysics Data System (ADS)

    Zan, Hsiao-Wen; Chen, Wei-Tsung; Hsueh, Hsiu-Wen; Kao, Shih-Chin; Ku, Ming-Che; Tsai, Chuang-Chuang; Meng, Hsin-Fei

    2010-11-01

    This work demonstrates a real-time visible-light phototransistor comprised of a wide-band-gap amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) and a narrow-band-gap polymeric capping layer. The capping layer and the IGZO layer form a p-n junction diode. The p-n junction absorbs visible light and consequently injects electrons into the IGZO layer, which in turn affects the body voltage as well as the threshold voltage of a-IGZO TFT. The hysteresis behavior due to the charges at IGZO back interface is also discussed.

  4. Charge pumping method for photosensor application by using amorphous indium-zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Liu, Po-Tsun; Chou, Yi-Teh; Teng, Li-Feng

    2009-06-01

    The study investigated the photoreaction behavior of amorphous indium-zinc oxide thin film transistor (a-IZO TFT), which was thought to be insensitive to visible light. The obvious threshold voltage shift was observed after light illumination, and it exhibited slow recovery while returning to initial status. The photoreaction mechanism is well explained by the dynamic equilibrium of charge exchange reaction between O2(g) and O2- in a-IZO layer. A charge pumping technique is used to confirm the mechanism and accelerate recoverability. Using knowledge of photoreaction behavior, an operation scheme of photosensing elements consist of a-IZO TFT is also demonstrated in this work.

  5. Constrained, aqueous growth of three-dimensional single crystalline zinc oxide structures

    SciTech Connect

    Pooley, Kathryn J. Joo, John H.; Hu, Evelyn L.

    2014-01-01

    We study low temperature (90 °C) aqueous growth of single crystal zinc oxide structures through patterned PMMA molds of different sizes, shapes, and orientations. We demonstrate the ability to create 3D shapes with smooth vertical sidewalls. Although the unconstrained growth is influenced by the hexagonal geometry of the underlying crystal structure, the ZnO is shown to conform exactly to any shape patterned. Using electron backscatter diffraction and scanning electron microscopy we show that the mold orientation, in conjunction with control of the growth rates of the c and m planes of the ZnO, is crucial in determining the final structure shape.

  6. Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

    SciTech Connect

    Hanna, A. N.; Ghoneim, M. T.; Bahabry, R. R.; Hussain, A. M.; Hussain, M. M.

    2013-11-25

    We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

  7. Chemical etching of zinc oxide for thin-film silicon solar cells.

    PubMed

    Hüpkes, Jürgen; Owen, Jorj I; Pust, Sascha E; Bunte, Eerke

    2012-01-16

    Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided.

  8. Paired-pulse facilitation achieved in protonic/electronic hybrid indium gallium zinc oxide synaptic transistors

    SciTech Connect

    Guo, Li Qiang Ding, Jian Ning; Huang, Yu Kai; Zhu, Li Qiang

    2015-08-15

    Neuromorphic devices with paired pulse facilitation emulating that of biological synapses are the key to develop artificial neural networks. Here, phosphorus-doped nanogranular SiO{sub 2} electrolyte is used as gate dielectric for protonic/electronic hybrid indium gallium zinc oxide (IGZO) synaptic transistor. In such synaptic transistors, protons within the SiO{sub 2} electrolyte are deemed as neurotransmitters of biological synapses. Paired-pulse facilitation (PPF) behaviors for the analogous information were mimicked. The temperature dependent PPF behaviors were also investigated systematically. The results indicate that the protonic/electronic hybrid IGZO synaptic transistors would be promising candidates for inorganic synapses in artificial neural network applications.

  9. Gas sensors based on polyaniline/zinc oxide hybrid film for ammonia detection at room temperature

    NASA Astrophysics Data System (ADS)

    Zhu, Guotao; Zhang, Qiuping; Xie, Guangzhong; Su, Yuanjie; Zhao, Kang; Du, Hongfei; Jiang, Yadong

    2016-11-01

    Polyaniline/zinc oxide (PANI/ZnO) hybrid film based sensors have been developed for ammonia (NH3) detection at room temperature (RT). Results shows that hybrid film sensor exhibits a p-type semiconductor behavior and larger response than that of pure PANI film sensor. In the system, ZnO nanorod arrays can not only create nanoscale gap for gas diffusion but also provide abundant adsorption sites, thus leading to enhancement of response. Besides, hydrothermal time is proportional to the length of nanorods, Longer nanorods will provide efficient gap for gas diffusion, which leads to better sensitivity. This work offers a promising way to optimize sensor performance.

  10. Aging of zinc oxide varistors subjected to partial discharges in sulfur hexafluoride

    NASA Astrophysics Data System (ADS)

    Bui, A.; Khedim, A.; Loubière, A.; Kourdi, M. B.

    1991-01-01

    The behavior of zinc oxide varistors subject to partial discharges in sulfur hexafluoride is studied with respect to their protective coating (glass and epoxy resin). Sulfur hexafluoride (SF6) is used as an insulating medium for the electrical equipment because of its high dielectric strength and good heat transfer properties. The decomposition of SF6 and residual impurities can considerably influence the varistor current-voltage characteristics essentially in the ohmic region. An analysis of the phenomenon shows that the degradation is due to a conducting deposit around the varistors and a physical corrosion of the coating.

  11. Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide

    SciTech Connect

    El-Said, A. S. E-mail: a.s.el-said@hzdr.de; Moslem, W. M.; Djebli, M.

    2014-06-09

    Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1 keV and 23.3 keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

  12. Green synthesis, characterization, and anticancer activity of hyaluronan/zinc oxide nanocomposite

    PubMed Central

    Namvar, Farideh; Azizi, Susan; Rahman, Heshu Sulaiman; Mohamad, Rosfarizan; Rasedee, Abdullah; Soltani, Mozhgan; Rahim, Raha Abdul

    2016-01-01

    The study describes an in situ green biosynthesis of zinc oxide nanocomposite using the seaweed Sargassum muticum water extract and hyaluronan biopolymer. The morphology and optical properties of the hyaluronan/zinc oxide (HA/ZnO) nanocomposite were determined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet–vis analysis. Electron microscopy and X-ray diffraction analysis showed that the zinc oxide nanoparticles were polydispersed with a mean size of 10.2±1.5 nm. The nanoparticles were mostly hexagonal in crystalline form. The HA/ZnO nanocomposite showed the absorption properties in the ultraviolet zone that is ascribed to the band gap of zinc oxide nanocomposite. In the cytotoxicity study, cancer cells, pancreatic adenocarcinoma (PANC-1), ovarian adenocarcinoma (CaOV-3), colonic adenocarcinoma (COLO205), and acute promyelocytic leukemia (HL-60) cells were treated with HA/ZnO nanocomposite. At 72 hours of treatment, the half maximal inhibitory concentration (IC50) value via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was 10.8±0.3 μg/mL, 15.4±1.2 μg/mL, 12.1±0.9 μg/mL, and 6.25±0.5 μg/mL for the PANC-1, CaOV-3, COLO-205, and HL-60 cells, respectively, showing that the composite is most toxic to the HL-60 cells. On the other hand, HA/ZnO nanocomposite treatment for 72 hours did not cause toxicity to the normal human lung fibroblast (MRC-5) cell line. Using fluorescent dyes and flow cytometry analysis, HA/ZnO nanocomposite caused G2/M cell cycle arrest and stimulated apoptosis-related increase in caspase-3 and -7 activities of the HL-60 cells. Thus, the study shows that the HA/ZnO nanocomposite produced through green synthesis has great potential to be developed into an efficacious therapeutic agent for cancers. PMID:27555781

  13. Zinc oxide tetrapods inhibit herpes simplex virus infection of cultured corneas

    PubMed Central

    Duggal, Neil; Jaishankar, Dinesh; Yadavalli, Tejabhiram; Hadigal, Satvik; Mishra, Yogendra Kumar; Adelung, Rainer

    2017-01-01

    Purpose Infection of the human cornea by herpes simplex virus type-1 (HSV-1) can cause significant vision loss. The purpose of this study was to develop an ex vivo model to visualize viral growth and spread in the cornea. The model was also used to analyze cytokine production and study the antiviral effects of zinc oxide tetrapods. Methods A β-galactosidase-expressing recombinant virus, HSV-1(KOS)tk12, was used to demonstrate the ability of the virus to enter and develop blue plaques on human corneal epithelial (HCE) cells and corneal tissues. Freshly obtained porcine corneas were cultured and then scratched before infection with HSV-1(KOS)tk12. The blue plaques on the corneas were imaged using a stereomicroscope. Western blot analysis for HSV-1 proteins was performed to verify HSV-1 infection of the cornea. Using the ex vivo model, zinc oxide tetrapods were tested for their anti-HSV-1 potential, and a cytokine profile was developed to assess the effects of the treatment. Results Cultured corneas and the use of β-galactosidase-expressing HSV-1(KOS)tk12 virus can provide an attractive ex vivo model to visualize and study HSV-1 entry and spread of the infection in tissues. We found that unlike cultured HCE cells, which demonstrated nearly 100% infectivity, HSV-1 infection of the cultured cornea was more restrictive and took longer to develop. We also found that the zinc oxide tetrapod–shaped nano- and microstructures inhibited HSV infection of the cultured cells, as well as the cultured corneas. The cytokine profile of the infected samples was consistent with previous studies of HSV-1 corneal infection. Conclusions The ability to visualize HSV-1 growth and spread in corneal tissues can provide new details about HSV-1 infection of the cornea and the efficacy of new cornea-specific antiviral drug candidates. The ex vivo model also demonstrates antiviral effects of zinc oxide tetrapods and adequately portrays the drug delivery issues that cornea-specific treatments

  14. Fabrication of inverted zinc oxide photonic crystal using sol-gel solution by spin coating method.

    PubMed

    Huang, Kuo-Min; Ho, Chong-Lung; Chang, Heng-Jui; Wu, Meng-Chyi

    2013-01-01

    Inverted zinc oxide photonic crystal structures were fabricated from polystyrene sphere (PSS) template using the sol-gel solution of ZnO by spin-coating method. It is easily able to control and fabricate the photonic crystal structures using the self-organized PSS with a size of 193 nm. The inverted ZnO photonic crystal structures observed show the (111) tendency of the hexagonal compact arrangement formation. The resulting structures possess the photonic band gaps in the near-ultraviolet range and exhibit an enhanced photoluminescence spectrum. The technology can effectively increase the light output intensity or efficiency for the applications of optoelectronic devices.

  15. Highly bendable characteristics of amorphous indium-gallium-zinc-oxide transistors embedded in a neutral plane

    NASA Astrophysics Data System (ADS)

    Park, Chang Bum; Na, HyungIl; Yoo, Soon Sung; Park, Kwon-Shik

    2015-11-01

    The electromechanical response of an amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) fabricated on a polyimide substrate was investigated as a function of the neutral axis location and strain history of the bending system. Here, we demonstrate the pronounced bending characteristics of a-IGZO TFTs and their backplane under extreme mechanical strain when they are embedded in a neutral plane (NP). After being subjected to tensile stress, the devices positioned near the NP were observed to function well against a cyclic bending stress of 2 mm radius with 100,000 times, while TFTs farther from the neutral surface exhibited modified electrical properties.

  16. In situ integration of freestanding zinc oxide nanorods using copper silicide nanobeams

    NASA Astrophysics Data System (ADS)

    Kumar, Nitin; Parajuli, Omkar; Hahm, Jong-in

    2007-10-01

    In this letter, we describe an in situ integration method to produce freestanding zinc oxide nanorods (ZnO NRs) on copper silicide nanobeams (Cu3Si NBs). The integration of ZnO NRs with Cu3Si NBs is straightforwardly achieved immediately after ZnO NR synthesis by exploiting self-assembled Cu3Si NBs as catalysts. The resulting ZnO NRs on Cu3Si NBs exhibit atomic defect-free structures with superb optical quality which, in turn, can be beneficial when applied in micro- and nanoelectromechanical systems.

  17. Zinc oxide nanostructures with metal particles based on surface plasmons for optoelectronic device applications

    NASA Astrophysics Data System (ADS)

    Yu, Jae Su; Ko, Yeong Hwan; Lee, Hee Kwan; Leem, Jung Woo

    2011-02-01

    We fabricate various ZnO (zinc oxide) nanostructures, such as nanorods, nanotips and nanoflowers, as well as ZnO subwavelength grating structures for applications in optoelectronic devices such as solar cells, light emitting diodes, and biosensors. The optical properties are theoretically analyzed using the rigorous coupled-wave analysis method. The fabricated ZnO nanostructures are of wurzite crystal structure. The reflection and absorption characteristics depend strongly on the shape and geometry of Zn nanostructures. The ZnO nanostructures with Au (or Ag) particles, based on surface plasmons, are also investigated.

  18. Surfactant Assisted Sonochemical Synthesis and Characterization of Gadolinium Doped Zinc Oxide Nanoparticles.

    PubMed

    Khajuria, Heena; Ladol, Jigmet; Singh, Rajinder; Khajuria, Sonika; Khajuria, Haq N

    2015-01-01

    Pure and Gd doped Zinc Oxide (ZnO) nanoparticles were synthesized by sonochemical method using different surfactants (PVP/CTAB). The nanoparticles were characterized by powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), particle size analysis by DLS technique and UV-Visible spectroscopy. The effect of Gd doping and nature of surfactants on crystallite size, morphology and band gap of ZnO nanoparticles have been investigated. In addition to this, the effect of nature of surfactant on amount of dopant inserted in the ZnO lattice was also studied.

  19. Analysis of indium zinc oxide thin films by laser-induced breakdown spectroscopy

    SciTech Connect

    Popescu, A. C.; Beldjilali, S.; Socol, G.; Mihailescu, I. N.; Craciun, V.; Hermann, J.

    2011-10-15

    We have performed spectroscopic analysis of the plasma generated by Nd:YAG ({lambda} = 266 nm) laser irradiation of thin indium zinc oxide films with variable In content deposited by combinatorial pulsed laser deposition on glass substrates. The samples were irradiated in 5 x 10{sup 4} Pa argon using laser pulses of 5 ns duration and 10 mJ energy. The plasma emission spectra were recorded with an Echelle spectrometer coupled to a gated detector with different delays with respect to the laser pulse. The relative concentrations of indium and zinc were evaluated by comparing the measured spectra to the spectral radiance computed for a plasma in local thermal equilibrium. Plasma temperature and electron density were deduced from the relative intensities and Stark broadening of spectral lines of atomic zinc. Analyses at different locations on the deposited thin films revealed that the In/(In + Zn) concentration ratio significantly varies over the sample surface, from 0.4 at the borders to about 0.5 in the center of the film. The results demonstrate that laser-induced breakdown spectroscopy allows for precise and fast characterization of thin films with variable composition.

  20. Sensing behaviour of nanosized zinc-tin composite oxide towards liquefied petroleum gas and ethanol

    SciTech Connect

    Singh, Ravi Chand; Singh, Onkar; Singh, Manmeet Pal; Chandi, Paramdeep Singh; Thangaraj, R.

    2010-09-15

    A chemical route has been used to synthesize composite oxides of zinc and tin. An ammonia solution was added to equal amounts of zinc and tin chloride solutions of same molarities to obtain precipitates. Three portions of these precipitates were annealed at 400, 600 and 800 {sup o}C, respectively. Results of X-ray diffraction and transmission electron microscopy clearly depicted coexistence of phases of nano-sized SnO{sub 2}, ZnO, Zn{sub 2}SnO{sub 4} and ZnSnO{sub 3}. The effect of annealing on structure, morphology and sensing has been observed as well. It has been observed that annealing promoted growth of Zn{sub 2}SnO{sub 4} and ZnSnO{sub 3} at the expense of zinc. The sensing response of fabricated sensors from these materials to 250 ppm LPG and ethanol has been investigated. The sensor fabricated from powder annealed at 400 {sup o}C responded better to LPG than ethanol.

  1. Electron Transport Layer-Free Inverted Organic Solar Cells Fabricated with Highly Transparent Low-Resistance Indium Gallium Zinc Oxide/Ag/Indium Gallium Zinc Oxide Multilayer Electrode

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ho; Kwon, Sung-Nam; Na, Seok-In; Kim, Sun-Kyung; Yoo, Young-Zo; Im, Hyeong-Seop; Seong, Tae-Yeon

    2017-04-01

    Inverted organic solar cells (OSCs) have been fabricated with conventional Sn-doped indium oxide (ITO) and amorphous indium gallium zinc oxide (a-IGZO)/Ag/a-IGZO (39 nm/19 nm/39 nm) (a-IAI) electrodes and their electrical characteristics characterized. The ITO and optimized a-IAI electrodes showed high transmittance of 96% and 88% at 500 nm, respectively. The carrier concentration and sheet resistance of the ITO and a-IAI films were 8.46 × 1020 cm-3 and 7.96 × 1021 cm-3 and 14.18 Ω/sq and 4.24 Ω/sq, respectively. Electron transport layer (ETL)-free OSCs with the a-IAI electrode exhibited power conversion efficiency (PCE) of 2.66%, similar to that of ZnO ETL-based OSCs with ITO electrode (3.27%). However, the ETL-free OSCs with the a-IAI electrode showed much higher PCE than the ETL-free OSCs with the ITO electrode (0.84%). Ultraviolet photoelectron spectroscopy results showed that the work function of the a-IAI electrode was 4.15 eV. This improved performance was attributed to the various roles of the a-IAI electrode, e.g., as an effective ETL and a hole blocking layer.

  2. Achievement of a high-mobility FET with a cloud-aligned composite oxide semiconductor

    NASA Astrophysics Data System (ADS)

    Yamazaki, Shunpei; Shima, Yukinori; Hosaka, Yasuharu; Okazaki, Kenichi; Koezuka, Junichi

    2016-11-01

    We have recently discovered that films of a widely used In-Ga-Zn oxide (IGZO) with \\text{In}:\\text{Ga}:\\text{Zn} = 1:1:1 have different material composition states when sputter-deposited under different conditions using the same polycrystalline IGZO target. Significant improvements in on-state current and mobility (as high as 40 cm2·V-1·s-1) are obtained. The results of local composition analysis indicate that the deposited film is not composed of any known homogeneous IGZO compound and that the components of this film are separated into two types of nanoparticle regions: one type is composed mainly of GaO x and GaZnO x , which contribute to on/off (switching) characteristics, and the other is composed mainly of InO x and InZnO x , which contribute to on-state characteristics. These regions constitute a new type of oxide semiconductor (OS) film. The nanoparticles with a blurry boundary extend like a cloud, probably complementing one another. We consider that this OS film has a novel composition, which can be described as a “cloud-aligned composite OS” (CAC-OS).

  3. Zinc thiolate reactivity toward nitrogen oxides: insights into the interaction of Zn2+ with S-nitrosothiols and implications for nitric oxide synthase.

    PubMed

    Kozhukh, Julia; Lippard, Stephen J

    2012-07-02

    Zinc thiolate complexes containing N(2)S tridentate ligands were prepared to investigate their reactivity toward reactive nitrogen species, chemistry proposed to occur at the zinc tetracysteine thiolate site of nitric oxide synthase (NOS). The complexes are unreactive toward nitric oxide (NO) in the absence of dioxygen, strongly indicating that NO cannot be the species directly responsible for S-nitrosothiol formation and loss of Zn(2+) at the NOS dimer interface in vivo. S-Nitrosothiol formation does occur upon exposure of zinc thiolate solutions to NO in the presence of air, however, or to NO(2) or NOBF(4), indicating that these reactive nitrogen/oxygen species are capable of liberating zinc from the enzyme, possibly through generation of the S-nitrosothiol. Interaction between simple Zn(2+) salts and preformed S-nitrosothiols leads to decomposition of the -SNO moiety, resulting in release of gaseous NO and N(2)O. The potential biological relevance of this chemistry is discussed.

  4. Enhanced oxidative stress resistance through activation of a zinc deficiency transcription factor in Brachypodium distachyon.

    PubMed

    Glover-Cutter, Kira M; Alderman, Stephen; Dombrowski, James E; Martin, Ruth C

    2014-11-01

    Identification of viable strategies to increase stress resistance of crops will become increasingly important for the goal of global food security as our population increases and our climate changes. Considering that resistance to oxidative stress is oftentimes an indicator of health and longevity in animal systems, characterizing conserved pathways known to increase oxidative stress resistance could prove fruitful for crop improvement strategies. This report argues for the usefulness and practicality of the model organism Brachypodium distachyon for identifying and validating stress resistance factors. Specifically, we focus on a zinc deficiency B. distachyon basic leucine zipper transcription factor, BdbZIP10, and its role in oxidative stress in the model organism B. distachyon. When overexpressed, BdbZIP10 protects plants and callus tissue from oxidative stress insults, most likely through distinct and direct activation of protective oxidative stress genes. Increased oxidative stress resistance and cell viability through the overexpression of BdbZIP10 highlight the utility of investigating conserved stress responses between plant and animal systems.

  5. Zinc oxide/redox mediator composite films-based sensor for electrochemical detection of important biomolecules.

    PubMed

    Tang, Chun-Fang; Kumar, S Ashok; Chen, Shen-Ming

    2008-09-15

    Electrochemical oxidation of serotonin (SN) onto zinc oxide (ZnO)-coated glassy carbon electrode (GCE) results in the generation of redox mediators (RMs) that are strongly adsorbed on electrode surface. The electrochemical properties of zinc oxide-electrogenerated redox mediator (ZnO/RM) (inorganic/organic) hybrid film-coated electrode has been studied using cyclic voltammetry (CV). The scanning electron microscope (SEM), atomic force microscope (AFM), and electrochemical techniques proved the immobilization of ZnO/RM core/shell microparticles on the electrode surface. The GCE modified with ZnO/RM hybrid film showed two reversible redox peaks in acidic solution, and the redox peaks were found to be pH dependent with slopes of -62 and -60 mV/pH, which are very close to the Nernst behavior. The GCE/ZnO/RM-modified electrode exhibited excellent electrocatalytic activity toward the oxidations of ascorbic acid (AA), dopamine (DA), and uric acid (UA) in 0.1M phosphate buffer solution (PBS, pH 7.0). Indeed, ZnO/RM-coated GCE separated the anodic oxidation waves of DA, AA, and UA with well-defined peak separations in their mixture solution. Consequently, the GCE/ZnO/RMs were used for simultaneous detection of DA, AA, and UA in their mixture solution. Using CV, calibration curves for DA, AA, and UA were obtained over the range of 6.0 x 10(-6) to 9.6 x 10(-4)M, 1.5 x 10(-5) to 2.4 x 10(-4)M, and 5.0 x 10(-5) to 8 x 10(-4)M with correlation coefficients of 0.992, 0.991, and 0.989, respectively. Moreover, ZnO/RM-modified GCE had good stability and antifouling properties.

  6. Development of Piezoelectric Zinc Oxide Nanoparticle-Poly(Vinylidene Fluoride) Nanocomposites for Sensing and Actuation

    NASA Astrophysics Data System (ADS)

    Dodds, John Steven

    Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory and field tests and have demonstrated significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. Piezoelectric nanocomposites, which enjoy a combination of the best properties of these material types, are at the forefront of emerging SHM technologies. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and actuation. It will be shown that these films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. The results obtained from this research will be crucial for future SHM applications using these piezoelectric nanocomposites. This study began with spin coating dispersed ZnO-based solutions for piezoelectric nanocomposite fabrication. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5% increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled at 50 MV-m-1 to permanently align film electrical domains and to enhance bulk film

  7. Phosphorus Doping Effect in a Zinc Oxide Channel Layer to Improve the Performance of Oxide Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Han, Dong-Suk; Moon, Yeon-Keon; Lee, Sih; Kim, Kyung-Taek; Moon, Dae-Yong; Lee, Sang-Ho; Kim, Woong-Sun; Park, Jong-Wan

    2012-09-01

    In this study, we fabricated phosphorus-doped zinc oxide-based thin-film transistors (TFTs) using direct current (DC) magnetron sputtering at a relatively low temperature of 100°C. To improve the TFT device performance, including field-effect mobility and bias stress stability, phosphorus dopants were employed to suppress the generation of intrinsic defects in the ZnO-based semiconductor. The positive and negative bias stress stabilities were dramatically improved by introducing the phosphorus dopants, which could prevent turn-on voltage ( V ON) shift in the TFTs caused by charge trapping within the active channel layer. The study showed that phosphorus doping in ZnO was an effective method to control the electrical properties of the active channel layers and improve the bias stress stability of oxide-based TFTs.

  8. Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers

    SciTech Connect

    György, E.; Pérez del Pino, A.; Logofatu, C.; Duta, A.; Isac, L.

    2014-07-14

    Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (λ = 266 nm, τ{sub FWHM} ≅ 3 ns, ν = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 10{sup 4} Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

  9. Hybrid transparent conductive electrodes with copper nanowires embedded in a zinc oxide matrix and protected by reduced graphene oxide platelets

    NASA Astrophysics Data System (ADS)

    Zhu, Zhaozhao; Mankowski, Trent; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

    2016-02-01

    Transparent conductive electrodes (TCE) were fabricated by combining three emerging nano-materials: copper nanowires (CuNWs), zinc oxide (ZnO) nano-particulate thin films, and reduced graphene oxide (rGO) platelets. Whereas CuNWs are responsible for essentially all of the electrical conductivity of our thin-film TCEs, the ZnO matrix embeds and strengthens the CuNW network in its adhesion to the substrate, while the rGO platelets provide a protective overcoat for the composite electrode, thereby improving its stability in hot and humid environments. Our CuNW/ZnO/rGO hybrid electrodes deposited on glass substrates have low sheet resistance (Rs ˜ 20 Ω/sq) and fairly high optical transmittance (T550 ˜ 79%). In addition, our hybrid TCEs are mechanically strong and able to withstand multiple scotch-tape peel tests. Finally, these TCEs can be fabricated on rigid glass as well as flexible plastic substrates.

  10. Enhanced violet photoemission of nanocrystalline fluorine doped zinc oxide (FZO) thin films

    NASA Astrophysics Data System (ADS)

    Anusha, Muthukumar; Arivuoli, D.; Manikandan, E.; Jayachandran, M.

    2015-09-01

    Highly stable fluorine doped nanocrystalline zinc oxide thin films were prepared on corning glass substrates by aerosol assisted chemical vapor deposition (AACVD) at variable deposition temperature of 360 °C, 380 °C and 420 °C. Especially, the optimum deposition temperature was investigated for high intense violet emission. The film crystallinity improved with the increasing deposition temperature and highly textured film was obtained at 420 °C. The films exhibited surface morphology variation from spherical to platelets due to deposition temperature effect, analyzed by field emission scanning electron microscope (FE-SEM). Higher growth rate observed at 420 °C which leads larger grains and lowest resistivity of ∼5.77 Ω cm among the deposited films which may be due to reduction in zinc vacancies and grain boundary area. Zinc vacancies are acts as electron killer centres. UV-visible spectra indicated higher transmittance (83-90%) in the visible region. Red shift of optical absorption edges associated with the increase in particle size consistent well with the XRD results. Reduced E2(high) intensity was observed in Raman spectra, for the film deposited at 380 °C which indicates decreased oxygen incorporation confirmed by PL spectra. Especially, enhanced violet emission observed at 3.06 eV for the films deposited at 380 °C due to electronic transition from the defect level of zinc vacancies to the conduction band, probably attributed to enhanced incorporation of 'F' into 'O' sites associated with increased Zn vacancies and also decreased oxygen incorporation consistent with the electrical and Raman analyses.

  11. Plasmon resonance and perfect light absorption in subwavelength trench arrays etched in gallium-doped zinc oxide film

    SciTech Connect

    Hendrickson, Joshua R. Leedy, Kevin; Cleary, Justin W.; Vangala, Shivashankar; Nader, Nima; Guo, Junpeng

    2015-11-09

    Near-perfect light absorption in subwavelength trench arrays etched in highly conductive gallium-doped zinc oxide films was experimentally observed in the mid infrared regime. At wavelengths corresponding to the resonant excitation of surface plasmons, up to 99% of impinging light is efficiently trapped and absorbed in the periodic trenches. Scattering cross sectional calculations reveal that each individual trench acts like a vertical split ring resonator with a broad plasmon resonance spectrum. The coupling of these individual plasmon resonators in the grating structure leads to enhanced photon absorption and significant resonant spectral linewidth narrowing. Ellipsometry measurements taken before and after device fabrication result in different permittivity values for the doped zinc oxide material, indicating that localized annealing occurred during the plasma etching process due to surface heating. Simulations, which incorporate a 50 nm annealed region at the zinc oxide surface, are in a good agreement with the experimental results.

  12. Visible-light-enhanced interactions of hydrogen sulfide with composites of zinc (oxy)hydroxide with graphite oxide and graphene.

    PubMed

    Seredych, Mykola; Mabayoje, Oluwaniyi; Bandosz, Teresa J

    2012-01-17

    Composites of zinc(oxy)hydroxide-graphite oxide and of zinc(oxy)hydroxide-graphene were used as adsorbents of hydrogen sulfide under ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis, and nitrogen adsorption. An increase in the amount of H(2)S adsorbed/oxidized on their surfaces in comparison with that of pure Zn(OH)(2) is linked to the structure of the composite, the relative number of terminal hydroxyls, and the kind of graphene-based phase used. Although terminal groups are activated by a photochemical process, the graphite oxide component owing to the chemical bonds with the zinc(oxy)hydroxide phase and conductive properties helps in electron transfer, leading to more efficient oxygen activation via the formation of superoxide ions. Elemental sulfur, zinc sulfide, sulfite, and sulfate are formed on the surface. The formation of sulfur compounds on the surface of zinc(oxy)hydroxide during the course of the breakthrough experiments and thus Zn(OH)(2)-ZnS heterojunctions can also contribute to the increased surface activity of our materials. The results show the superiority of graphite oxide in the formation of composites owing to its active surface chemistry and the possibility of interface bond formation, leading to an increase in the number of electron-transfer reactions.

  13. On the Development of a Zinc Vapor Condensation Process for the Solar Carbothermal Reduction of Zinc Oxide

    NASA Astrophysics Data System (ADS)

    Tzouganatos, N.; Dell'amico, M.; Wieckert, C.; Hinkley, J.; Steinfeld, A.

    2015-05-01

    In the conventional Imperial Smelting Process, the dominating pyrometallurgical zinc production process, zinc vapor is recovered from the furnace off-gas by absorption into an intense spray of molten lead droplets in a splash condenser, followed by separation of zinc from the Zn-Pb alloy upon cooling from 550°C to 450°C by taking advantage of the decrease in the solubility of zinc in lead at lower temperatures. The adaptation of this condenser technology into a solar-driven thermochemical plant using concentrated solar energy faces several drawbacks owing to its mechanical complications and the continuous recirculation of large quantities of lead. An alternative zinc condenser concept involving gas bubbling through a zinc liquid bath of the off-gas evolved from the carbothermal reduction of ZnO is thus proposed and numerically modeled for transient heat and mass transfer. Condensation of bubbles containing 53.5% of noncondensable gases yielded chemical conversions of Zn(g) to Zn(l) in the range of 95.6-99.8% for operation in the temperature range 500-650°C while conversions of Zn(g) to ZnO in the order of 10-6 were obtained, thus predicting successful suppression of Zn(g) reoxidation by CO2 and CO.

  14. Effects of Long-Term Exposure to Zinc Oxide Nanoparticles on Development, Zinc Metabolism and Biodistribution of Minerals (Zn, Fe, Cu, Mn) in Mice.

    PubMed

    Wang, Chao; Lu, Jianjun; Zhou, Le; Li, Jun; Xu, Jiaman; Li, Weijian; Zhang, Lili; Zhong, Xiang; Wang, Tian

    2016-01-01

    Zinc oxide nanoparticles (nano-ZnOs) are widely used and possess great potentials in agriculture and biomedicine. It is inevitable for human exposure to these nanoparticles. However, no study had been conducted to investigate the long term effects of nano-ZnOs. This study aimed at investigating effects of nano-ZnOs on development, zinc metabolism and biodistribution of minerals (Zn, Fe, Cu, and Mn) in mice from week 3 to 35. After the characteristics of nano-ZnOs were determined, they were added into the basal diet at 0, 50, 500 and 5000 mg/kg. Results indicated that added 50 and 500 mg/kg nano-ZnOs showed minimal toxicity. However, 5000 mg/kg nano-ZnOs significantly decreased body weight (from week 4 to 16) and increased the relative weights of the pancreas, brain and lung. Added 5000 mg/kg nano-ZnOs significantly increased the serum glutamic-pyruvic transaminase activity and zinc content, and significantly enhanced mRNA expression of zinc metabolism-related genes, including metallothionein 1(32.66 folds), metallothionein 2 (31.42 folds), ZIP8 (2.21folds), ZIP14 (2.45 folds), ZnT1 (4.76 folds), ZnT2 (6.19 folds) and ZnT4 (1.82 folds). The biodistribution determination showed that there was a significant accumulation of zinc in the liver, pancreas, kidney, and bones (tibia and fibula) after receiving 5000 mg/kg nano-ZnO diet, while no significant effects on Cu, Fe, and Mn levels, except for liver Fe content and pancreas Mn level. Our results demonstrated that long term exposure to 50 and 500 mg/kg nano-ZnO diets showed minimal toxicity. However, high dose of nano-ZnOs (5000 mg/kg) caused toxicity on development, and altered the zinc metabolism and biodistribution in mice.

  15. Effects of Long-Term Exposure to Zinc Oxide Nanoparticles on Development, Zinc Metabolism and Biodistribution of Minerals (Zn, Fe, Cu, Mn) in Mice

    PubMed Central

    Wang, Chao; Lu, Jianjun; Zhou, Le; Li, Jun; Xu, Jiaman; Li, Weijian; Zhang, Lili; Zhong, Xiang; Wang, Tian

    2016-01-01

    Zinc oxide nanoparticles (nano-ZnOs) are widely used and possess great potentials in agriculture and biomedicine. It is inevitable for human exposure to these nanoparticles. However, no study had been conducted to investigate the long term effects of nano-ZnOs. This study aimed at investigating effects of nano-ZnOs on development, zinc metabolism and biodistribution of minerals (Zn, Fe, Cu, and Mn) in mice from week 3 to 35. After the characteristics of nano-ZnOs were determined, they were added into the basal diet at 0, 50, 500 and 5000 mg/kg. Results indicated that added 50 and 500 mg/kg nano-ZnOs showed minimal toxicity. However, 5000 mg/kg nano-ZnOs significantly decreased body weight (from week 4 to 16) and increased the relative weights of the pancreas, brain and lung. Added 5000 mg/kg nano-ZnOs significantly increased the serum glutamic-pyruvic transaminase activity and zinc content, and significantly enhanced mRNA expression of zinc metabolism-related genes, including metallothionein 1(32.66 folds), metallothionein 2 (31.42 folds), ZIP8 (2.21folds), ZIP14 (2.45 folds), ZnT1 (4.76 folds), ZnT2 (6.19 folds) and ZnT4 (1.82 folds). The biodistribution determination showed that there was a significant accumulation of zinc in the liver, pancreas, kidney, and bones (tibia and fibula) after receiving 5000 mg/kg nano-ZnO diet, while no significant effects on Cu, Fe, and Mn levels, except for liver Fe content and pancreas Mn level. Our results demonstrated that long term exposure to 50 and 500 mg/kg nano-ZnO diets showed minimal toxicity. However, high dose of nano-ZnOs (5000 mg/kg) caused toxicity on development, and altered the zinc metabolism and biodistribution in mice. PMID:27732669

  16. A facile chemical route for recovery of high quality zinc oxide nanoparticles from spent alkaline batteries.

    PubMed

    Deep, Akash; Sharma, Amit L; Mohanta, Girish C; Kumar, Parveen; Kim, Ki-Hyun

    2016-05-01

    Recycling of spent domestic batteries has gained a great environmental significance. In the present research, we propose a new and simple technique for the recovery of high-purity zinc oxide nanoparticles from the electrode waste of spent alkaline Zn-MnO2 batteries. The electrode material was collected by the manual dismantling and mixed with 5M HCl for reaction with a phosphine oxide reagent Cyanex 923® at 250°C for 30min. The desired ZnO nanoparticles were restored from the Zn-Cyanex 923 complex through an ethanolic precipitation step. The recovered particle product with about 5nm diameter exhibited fluorescent properties (emission peak at 400nm) when excited by UV radiation (excitation energy of 300nm). Thus, the proposed technique offered a simple and efficient route for recovering high purity ZnO nanoparticles from spent alkaline batteries.

  17. Transient characteristics for proton gating in laterally coupled indium-zinc-oxide transistors.

    PubMed

    Liu, Ning; Zhu, Li Qiang; Xiao, Hui; Wan, Chang Jin; Liu, Yang Hui; Chao, Jin Yu

    2015-03-25

    The control and detection over processing, transport and delivery of chemical species is of great importance in sensors and biological systems. The transient characteristics of the migration of chemical species reflect the basic properties in the processings of chemical species. Here, we observed the field-configurable proton effects in a laterally coupled transistor gated by phosphorosilicate glass (PSG). The bias on the lateral gate would modulate the interplay between protons and electrons at the PSG/indium-zinc-oxide (IZO) channel interface. Due to the modulation of protons flux within the PSG films, the IZO channel current would be modified correspondingly. The characteristic time for the proton gating is estimated to be on the order of 20 ms. Such laterally coupled oxide based transistors with proton gating are promising for low-cost portable biosensors and neuromorphic system applications.

  18. Deep Subgap Feature in Amorphous Indium Gallium Zinc Oxide. Evidence Against Reduced Indium

    SciTech Connect

    Sallis, Shawn; Quackenbush, Nicholas F.; Williams, Deborah S.; Senger, Mikell; Woicik, Joseph C.; White, Bruce E.; Piper, Louis F.

    2015-01-14

    Amorphous indium gallium zinc oxide (a-IGZO) is the archetypal transparent amorphous oxide semiconductor. In spite of the gains made with a-IGZO over amorphous silicon in the last decade, the presence of deep subgap states in a-IGZO active layers facilitate instabilities in thin film transistor properties under negative bias illumination stress. Several candidates could contribute to the formation of states within the band gap. We present evidence against In+ lone pair active electrons as the origin of the deep subgap features. No In+ species are observed, only In0 nano-crystallites under certain oxygen deficient growth conditions. Our results further support under coordinated oxygen as the source of the deep subgap states.

  19. Inkjet-printed zinc-tin-oxide TFTs with a solution-processed hybrid dielectric layer

    NASA Astrophysics Data System (ADS)

    Jang, Hye-Ryun; Kwack, Young-Jin; Choi, Woon-Seop

    2014-11-01

    Sol-gel TiO2 was synthesized and used as a gate dielectric for oxide thin-film transistors (TFTs). A hybrid gate insulator composed of sol-gel TiO2/thermally-grown SiO2 was applied to the inkjet-printed zinc-tin oxide (ZTO) TFTs for the first time. The electrical properties of an inkjet-printed ZTO TFT with a hybrid gate insulator show a mobility of 0.17 cm2/Vs, an on-to-off current ratio of 5 × 104, a subthreshold slope of 0.8 V/dec, and a threshold voltage of 0.6 V. The hybrid gate insulator for the inkjet-printed ZTO TFT shows a much improved operating voltage and subthreshold slope and a lower mobility compared to the SiO2 gate insulator.

  20. Characterization of Monolayer Formation on Aluminum-Doped Zinc Oxide Thin Films

    SciTech Connect

    Rhodes,C.; Lappi, S.; Fischer, D.; Sambasivan, S.; Genzer, J.; Franzen, S.

    2008-01-01

    The optical and electronic properties of aluminum-doped zinc oxide (AZO) thin films on a glass substrate are investigated experimentally and theoretically. Optical studies with coupling in the Kretschmann configuration reveal an angle-dependent plasma frequency in the mid-IR for p-polarized radiation, suggestive of the detection of a Drude plasma frequency. These studies are complemented by oxygen depletion density functional theory studies for the calculation of the charge carrier concentration and plasma frequency for bulk AZO. In addition, we report on the optical and physical properties of thin film adlayers of n-hexadecanethiol (HDT) and n-octadecanethiol (ODT) self-assembled monolayers (SAMs) on AZO surfaces using reflectance FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Our characterization of the SAM deposition onto the AZO thin film reveals a range of possible applications for this conducting metal oxide.

  1. Light extraction enhancement of organic light-emitting diodes using aluminum zinc oxide embedded anodes.

    PubMed

    Hsu, Ching-Ming; Lin, Bo-Ting; Zeng, Yin-Xing; Lin, Wei-Ming; Wu, Wen-Tuan

    2014-12-15

    Aluminum zinc oxide (AZO) has been embedded onto indium tin oxide (ITO) anode to enhance the light extraction from an organic light-emitting diode (OLED). The embedded AZO provides deflection and scattering interfaces on the newly generated AZO/organics and AZO/ITO interfaces rather than the conventional ITO/organic interface. The current efficiency of AZO embedded OLEDs was enhanced by up to 64%, attributed to the improved light extraction by additionally created reflection and scattering of emitted light on the AZO/ITO interfaces which was roughed in AZO embedding process. The current efficiency was found to increase with the increasing AZO embedded area ratio, but limited by the accompanying increases in haze and electrical resistance of the AZO embedded ITO film.

  2. Synthesis, characterization, and photocatalytic activities of titanate nanotubes surface-decorated by zinc oxide nanoparticles.

    PubMed

    Wang, Li Shi; Xiao, Ming Wei; Huang, Xin Jian; Wu, Yan Dan

    2009-01-15

    Nanoscaled zinc oxide (ZnO) particles with different amounts are coated on titanate nanotubes (TNTs) by a facile chemical method at room temperature. The characterizations of XPS, TEM, XRD and UV-vis spectra confirm that pure hexagonal wurtzite ZnO nanoparticles with an average size of about 9nm are distributed on the surfaces of TNTs evenly and attached strongly. The photocatalytic activities of the ZnO-TNTs nanocomposite are superior to those of P25, ZnO, TNTs and ZnO-anatase TiO2 (TNP) nanocomposite in the oxidation of rhodamine B under UV light irradiation. A comparison of the photocatalytic activities between different catalysts is discussed. Furthermore, we also find that the ZnO-TNT nanocomposite shows very favorable recycle use potential, because they have a high sedimentation rate and their photocatalytic activity is only slightly decreased even after five times of repeated uses.

  3. Hydrogen plasma treatment for improved conductivity in amorphous aluminum doped zinc tin oxide thin films

    SciTech Connect

    Morales-Masis, M. Ding, L.; Dauzou, F.; Jeangros, Q.; Hessler-Wyser, A.; Nicolay, S.; Ballif, C.

    2014-09-01

    Improving the conductivity of earth-abundant transparent conductive oxides (TCOs) remains an important challenge that will facilitate the replacement of indium-based TCOs. Here, we show that a hydrogen (H{sub 2})-plasma post-deposition treatment improves the conductivity of amorphous aluminum-doped zinc tin oxide while retaining its low optical absorption. We found that the H{sub 2}-plasma treatment performed at a substrate temperature of 50 °C reduces the resistivity of the films by 57% and increases the absorptance by only 2%. Additionally, the low substrate temperature delays the known formation of tin particles with the plasma and it allows the application of the process to temperature-sensitive substrates.

  4. Effect of Zinc oxide nanoparticle on Fluorescence Resonance Energy transfer between Fluorescein and Rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Saha, Jaba; Roy, Arpan Datta; Dey, Dibyendu; Bhattacharjee, D.; Paul, Pabitra Kumar; Das, R.; Hussain, Syed Arshad

    2017-03-01

    Fluorescence Resonance Energy Transfer between two dyes Fluorescein and Rhodamine 6G were investigated in solution in the presence and absence of Zinc oxide nanoparticle. Zinc oxide nanostructure is used as the fluorescence enhancing agent for the present study since donor (Fluorescein) fluorescence increase significantly in presence of nanoparticle. Accordingly, the energy transfer efficiency in the presence of nanoparticle increases. The maximum efficiency was 69% for acceptor (Rhodamine 6G) concentration of 0.75 × 10- 5 M. The energy transfer efficiency was found to be pH sensitive and it varies from 4.15% to 90.00% in mixed dye solution for a change in pH from 1.5 to 10.0. With proper calibration it is possible to use the present system under investigation to sense pH which is better with respect to our previous reported results [Spectrochim. Acta Part A. 149 (2015) 143-149] as it can sense a wide range of pH and with better sensitivity.

  5. Morphology control of zinc oxide films via polysaccharide-mediated, low temperature, chemical bath deposition

    PubMed Central

    Schneider, Andreas M; Eiden, Stefanie

    2015-01-01

    Summary In this study we present a three-step process for the low-temperature chemical bath deposition of crystalline ZnO films on glass substrates. The process consists of a seeding step followed by two chemical bath deposition steps. In the second step (the first of the two bath deposition steps), a natural polysaccharide, namely hyaluronic acid, is used to manipulate the morphology of the films. Previous experiments revealed a strong influence of this polysaccharide on the formation of zinc oxide crystallites. The present work aims to transfer this gained knowledge to the formation of zinc oxide films. The influence of hyaluronic acid and the time of its addition on the morphology of the resulting ZnO film were investigated. By meticulous adjustment of the parameters in this step, the film morphology can be tailored to provide an optimal growth platform for the third step (a subsequent chemical bath deposition step). In this step, the film is covered by a dense layer of ZnO. This optimized procedure leads to ZnO films with a very high electrical conductivity, opening up interesting possibilities for applications of such films. The films were characterized by means of electron microscopy, X-ray diffraction and measurements of the electrical conductivity. PMID:25977851

  6. Electrical and optical properties of molybdenum doped zinc oxide films prepared by reactive RF magnetron sputtering

    SciTech Connect

    Reddy, R. Subba; Sreedhar, A.; Uthanna, S.

    2015-08-28

    Molybdenum doped zinc oxide (MZO) films were deposited on to glass substrates held at temperatures in the range from 303 to 673 K by reactive RF magnetron sputtering method. The chemical composition, crystallographic structure and surface morphology, electrical and optical properties of the films were determined. The films contained the molybdenum of 2.7 at. % in ZnO. The films deposited at 303 K were of X-ray amorphous. The films formed at 473 K were of nanocrystalline in nature with wurtzite structure. The crystallite size of the films was increased with the increase of substrate temperature. The optical transmittance of the films was in the visible range was 80–85%. The molybdenum (2.7 at %) doped zinc oxide films deposited at substrate temperature of 573 K were of nanocrystalline with electrical resistivity of 7.2×10{sup −3} Ωcm, optical transmittance of 85 %, optical band gap of 3.35 eV and figure of merit 30.6 Ω{sup −1}cm{sup −1}.

  7. Magnesium-doped zinc oxide nanorod-nanotube semiconductor/p-silicon heterojunction diodes

    NASA Astrophysics Data System (ADS)

    Caglar, Yasemin; Görgün, Kamuran; Ilican, Saliha; Caglar, Mujdat; Yakuphanoğlu, Fahrettin

    2016-08-01

    Nanostructured zinc oxide material is usable in electronic device applications such as light-emitting diodes, heterojunction diode, sensors, solar cell due to its interesting electrical conductivity and optical properties. Magnesium-doped zinc oxide nanorod (NR)-nanotube (NT) films were grown by microwave-assisted chemical bath deposition to fabricate ZnO-based heterojunction diode. It is found that ZnO hexagonal nanorods turn into hexagonal nanotubes when the Mg doping ratio is increased from 1 to 10 %. The values of the optical band gap for 1 % Mg-doped ZnO NR and 10 % Mg-doped ZnO NT films are found to be 3.14 and 3.22 eV, respectively. The n-ZnO:Mg/p-Si heterojunction diodes were fabricated. The diodes exhibited a rectification behavior with ideality factor higher than unity due to the presence of surface states in the junction and series resistance. The obtained results indicate that Mg doping improves the electrical and optical properties of ZnO.

  8. Surface plasmon resonance based fiber optic detection of chlorine utilizing polyvinylpyrolidone supported zinc oxide thin films.

    PubMed

    Tabassum, Rana; Gupta, Banshi D

    2015-03-21

    A highly sensitive chlorine sensor for an aqueous medium is fabricated using an optical fiber surface plasmon resonance (OFSPR) system. An OFSPR-based chlorine sensor is designed with a multilayer-type platform by zinc oxide (ZnO) and polyvinylpyrollidone (PVP) film morphology manipulations. Among all the methodologies of transduction reported in the field of solid state chemical and biochemical sensing, our attention is focused on the Kretschmann configuration optical fiber sensing technique using the mechanism of surface plasmon resonance. The optical fiber surface plasmon resonance (SPR) chlorine sensor is developed using a multimode optical fiber with the PVP-supported ZnO film deposited over a silver-coated unclad core of the fiber. A spectral interrogation mode of operation is used to characterize the sensor. In an Ag/ZnO/PVP multilayer system, the absorption of chlorine in the vicinity of the sensing region is performed by the PVP layer and the zinc oxide layer enhances the shift in resonance wavelength. It is, experimentally, demonstrated that the SPR wavelength shifts nonlinearly towards the red side of the visible region with an increase in the chlorine concentration in an aqueous medium while the sensitivity of the sensor decreases linearly with an increase in the chlorine concentration. As the proposed sensor utilizes an optical fiber, it possesses the additional advantages of fiber such as less signal degradation, less susceptibility to electromagnetic interference, possibility of remote sensing, probe miniaturization, probe re-usability, online monitoring, small size, light weight and low cost.

  9. Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity.

    PubMed

    Guerreiro-Tanomaru, Juliane M; Pereira, Kamila Figueiredo; Nascimento, Camila Almeida; Bernardi, Maria Inês Basso; Tanomaru-Filho, Mario

    2013-01-01

    The aim of this study was to evaluate the pH and antimicrobial activity of micro or nanoparticulate zinc oxide (ZnO) pastes with or without calcium hydroxide (CH). The following medications were evaluated: microparticulate ZnO + polyethylene glycol (PEG) 400; nanoparticulate ZnO + PEG 400; PEG 400; CH + microparticulate ZnO + PEG 400 and CH + nanoparticulate ZnO + PEG 400. The pH was assessed between 12 hours and 28 days, using a digital pH meter. The antimicrobial activity against Enterococcus faecalis (ATCC-9212), Candida albicans (ATCC-10231), Pseudomonas aeruginosa (ATCC-27853), Staphylococcus aureus (ATCC-6538) and Kocuria rhizophila (ATCC-9341) was determined in triplicate using agar diffusion test. The results were submitted to Kruskal-Wallis/Dunn and ANOVA/Tukey tests with 5% significance. The highest pH values were found for CH+ZnO, with higher values for nanoparticulate ZnO after 12 hours and 21 days (p < 0.05). CH+ZnO medication promoted higher growth inhibition against P. aeruginosa and lower against E. faecalis. Calcium hydroxide pastes have higher pH and antimicrobial activity when associated with either micro- or nanoparticulate zinc oxide.

  10. Solubility of nano-zinc oxide in environmentally and biologically important matrices.

    PubMed

    Reed, Robert B; Ladner, David A; Higgins, Christopher P; Westerhoff, Paul; Ranville, James F

    2012-01-01

    Increasing manufacture and use of engineered nanoparticles is leading to a greater probability for release of engineered nanoparticles into the environment and exposure to organisms. In particular, zinc oxide (ZnO) is toxic, although it is unclear whether this toxicity is due to the zinc oxide nanoparticles, dissolution to Zn(2+) , or some combination thereof. The goal of this study was to determine the relative solubilities of both commercially available and in-house synthesized ZnO in matrices used for environmental fate and transport or biological toxicity studies. Dissolution of ZnO was observed in nanopure water (7.18-7.40 mg/L dissolved Zn, as measured by filtration) and Roswell Park Memorial Institute medium (RPMI-1640) (∼5 mg/L), but much more dissolution was observed in Dulbecco's modified Eagle's medium, in which the dissolved Zn concentration exceeded 34 mg/L. Moderately hard water exhibited low Zn solubility, likely because of precipitation of a Zn carbonate solid phase. Precipitation of a Zn-containing solid phase in RPMI also appeared to limit Zn solubility. Equilibrium conditions with respect to ZnO solubility were not apparent in these matrices, even after more than 1,000 h of dissolution. These results suggest that solution chemistry exerts a strong influence on ZnO dissolution and can result in limits on Zn solubility from precipitation of less soluble solid phases.

  11. Synchrotron Speciation of Silver and Zinc Oxide Nanoparticles Aged in a Kaolin Suspension

    SciTech Connect

    Scheckel, Kirk G.; Luxton, Todd P.; El Badawy, Amro M.; Impellitteri, Christopher A.; Tolaymat, Thabet M.

    2010-07-23

    Assessments of the environmental fate and mobility of nanoparticles must consider the behavior of nanoparticles in relevant environmental systems that may result in speciation changes over time. Environmental conditions may act on nanoparticles to change their size, shape, and surface chemistry. Changing these basic characteristics of nanoparticles may result in a final reaction product that is significantly different than the initial nanomaterial. As such, basing long-term risk and toxicity on the initial properties of a nanomaterial may lead to erroneous conclusions if nanoparticles change upon release to the environment. The influence of aging on the speciation and chemical stability of silver and zinc oxide nanoparticles in kaolin suspensions was examined in batch reactors for up to 18 months. Silver nanoparticles remained unchanged in sodium nitrate suspensions; however, silver chloride was identified with the metallic silver nanoparticles in sodium chloride suspensions and may be attributed to an in situ silver chloride surface coating. Zinc oxide nanoparticles were rapidly converted via destabilization/dissolution mechanisms to Zn{sup 2+} inner-sphere sorption complexes within 1 day of reaction and these sorption complexes were maintained through the 12 month aging processes. Chemical and physical alteration of nanomaterials in the environment must be examined to understand fate, mobility, and toxicology.

  12. Zinc Oxide Nanoparticle-Poly I:C RNA Complexes: Implication as Therapeutics against Experimental Melanoma.

    PubMed

    Ramani, Meghana; Mudge, Miranda C; Morris, R Tyler; Zhang, Yuntao; Warcholek, Stanislaw A; Hurst, Miranda N; Riviere, Jim E; DeLong, Robert K

    2017-03-06

    There is current interest in harnessing the combined anticancer and immunological effect of nanoparticles (NPs) and RNA. Here, we evaluate the bioactivity of poly I:C (pIC) RNA, bound to anticancer zinc oxide NP (ZnO-NP) against melanoma. Direct RNA association to unfunctionalized ZnO-NP is shown by observing change in size, zeta potential, and absorption/fluorescence spectra upon complexation. RNA corona was visualized by transmission electron microscopy (TEM) for the first time. Binding constant (Kb = 1.6-2.8 g(-1) L) was determined by modified Stern-Volmer, absorption, and biological surface activity index analysis. The pIC-ZnO-NP complex increased cell death for both human (A375) and mouse (B16F10) cell lines and suppressed tumor cell growth in BALB/C-B16F10 mouse melanoma model. Ex vivo tumor analysis indicated significant molecular activity such as changes in the level of phosphoproteins JNK, Akt, and inflammation markers IL-6 and IFN-γ. High throughput proteomics analysis revealed zinc oxide and poly I:C-specific and combinational patterns that suggested possible utility as an anticancer and immunotherapeutic strategy against melanoma.

  13. Biogenic synthesis of zinc oxide nanoparticles using Ruta graveolens (L.) and their antibacterial and antioxidant activities

    NASA Astrophysics Data System (ADS)

    Lingaraju, K.; Raja Naika, H.; Manjunath, K.; Basavaraj, R. B.; Nagabhushana, H.; Nagaraju, G.; Suresh, D.

    2016-06-01

    In the present investigation, green synthesis of zinc oxide nanoparticles were successfully synthesized by biological method using aqueous stem extract of Ruta graveolens act as reducing agent. Formation of ZnO nanoparticles were characterized by powder X-ray diffraction (PXRD), UV-visible spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Zinc oxide nanoparticles were subjected to biological properties such as antibacterial and antioxidant studies. The PXRD pattern reveals that ZnO sample belongs to hexagonal phase with Wurtzite structure. The UV-vis absorption spectrum shows an absorption band at 355 nm due to ZnO nanoparticles. SEM images show that the particles have spherical like structure with large surface area and the average crystallite sizes were found to be in the range ~28 nm. These observations were confirmed by TEM analysis. The ZnO nanoparticles are found to inhibit the antioxidant activity of 1,1-diphenyl-2-picrylhydrazyl free radicals effectively. ZnO Nps exhibit significant bactericidal activity against Gram -ve bacterial strains such as Klebsiella aerogenes, Pseudomonas aeruginosa, Escherichia coli and Gram +ve Staphylococcus aureus by agar well diffusion method.

  14. Aluminum-Doped Zinc Oxide as Highly Stable Electron Collection Layer for Perovskite Solar Cells.

    PubMed

    Zhao, Xingyue; Shen, Heping; Zhang, Ye; Li, Xin; Zhao, Xiaochong; Tai, Meiqian; Li, Jingfeng; Li, Jianbao; Li, Xin; Lin, Hong

    2016-03-01

    Although low-temperature, solution-processed zinc oxide (ZnO) has been widely adopted as the electron collection layer (ECL) in perovskite solar cells (PSCs) because of its simple synthesis and excellent electrical properties such as high charge mobility, the thermal stability of the perovskite films deposited atop ZnO layer remains as a major issue. Herein, we addressed this problem by employing aluminum-doped zinc oxide (AZO) as the ECL and obtained extraordinarily thermally stable perovskite layers. The improvement of the thermal stability was ascribed to diminish of the Lewis acid-base chemical reaction between perovskite and ECL. Notably, the outstanding transmittance and conductivity also render AZO layer as an ideal candidate for transparent conductive electrodes, which enables a simplified cell structure featuring glass/AZO/perovskite/Spiro-OMeTAD/Au. Optimization of the perovskite layer leads to an excellent and repeatable photovoltaic performance, with the champion cell exhibiting an open-circuit voltage (Voc) of 0.94 V, a short-circuit current (Jsc) of 20.2 mA cm(-2), a fill factor (FF) of 0.67, and an overall power conversion efficiency (PCE) of 12.6% under standard 1 sun illumination. It was also revealed by steady-state and time-resolved photoluminescence that the AZO/perovskite interface resulted in less quenching than that between perovskite and hole transport material.

  15. Transition metal-modified zinc oxides for UV and visible light photocatalysis.

    PubMed

    Bloh, J Z; Dillert, R; Bahnemann, D W

    2012-11-01

    In order to use photocatalysis with solar light, finding more active and especially visible light active photocatalysts is a very important challenge. Also, studies of these photocatalysts should employ a standardized test procedure so that their results can be accurately compared and evaluated with one another. A systematic study of transition metal-modified zinc oxide was conducted to determine whether they are suitable as visible light photocatalysts. The photocatalytic activity of ZnO modified with eight different transition metals (Cu, Co, Fe, Mn, Ni, Ru, Ti, Zr) in three different concentrations (0.01, 0.1, and 1 at.%) was investigated under irradiation with UV as well as with visible light. The employed activity test is the gas-phase degradation of acetaldehyde as described by the ISO standard 22197-2. The results suggest that the UV activity can be improved with almost any modification element and that there exists an optimal modification ratio at about 0.1 at.%. Additionally, Mn- and Ru-modified ZnO display visible light activity. Especially the Ru-modified ZnO is highly active and surpasses the visible light activity of all studied titania standards. These findings suggest that modified zinc oxides may be a viable alternative to titanium dioxide-based catalysts for visible light photocatalysis. Eventually, possible underlying mechanisms are proposed and discussed.

  16. Subcutaneous Connective Tissue Reaction to a New Nano Zinc-Oxide Eugenol Sealer in Rat Model

    PubMed Central

    Omidi, Salma; Javidi, Maryam; Zarei, Mina; Mushakhian, Siavash; Jafarian, Amirhossein

    2017-01-01

    Introduction: The aim of this animal study was to evaluate the histological response of the new nano zinc-oxide eugenol (NZOE) sealer in comparison with Pulp Canal Sealer (ZOE based) and AH-26 (epoxy resin sealer). Methods and Materials: A total of 27 Wistar rats were used. Four polyethylene tubes were implanted in the back of each rat (three tubes containing the test materials and an empty tube as a control). Then, 9 animals were sacrificed at each interval of 15, 30 and 60 days, and the implants were removed with the surrounding tissues.Samples were evaluated for the presence of inflammatory cell (mononuclear cell), vascular changes, fibrous tissue formation and present of giant cell. Comparisons between groups and time-periods were performed using the Kruskal-Wallis and Mann-Whitney U non-parametric tests. The level of significance was set at 0.05. Results: No significant difference was observed in tissue reactions and biocompatibility pattern of three sealers during 3 experimental periods (P<0.05). In all groups the tissue behavior showed tendency to decrease the irritation effect over time. Conclusion: The new nano zinc-oxide eugenol sealer has histocompatibility properties comparable to conventional commercial sealers. PMID:28179927

  17. Graphene, carbon nanotubes, zinc oxide and gold as elite nanomaterials for fabrication of biosensors for healthcare.

    PubMed

    Kumar, Sandeep; Ahlawat, Wandit; Kumar, Rajesh; Dilbaghi, Neeraj

    2015-08-15

    Technological advancements worldwide at rapid pace in the area of materials science and nanotechnology have made it possible to synthesize nanoparticles with desirable properties not exhibited by the bulk material. Among variety of available nanomaterials, graphene, carbon nanotubes, zinc oxide and gold nanopartilces proved to be elite and offered amazing electrochemical biosensing. This encourages us to write a review which highlights the recent achievements in the construction of genosensor, immunosensor and enzymatic biosensor based on the above nanomaterials. Carbon based nanomaterials offers a direct electron transfer between the functionalized nanomaterials and active site of bioreceptor without involvement of any mediator which not only amplifies the signal but also provide label free sensing. Gold shows affinity towards immunological molecules and is most routinely used for immunological sensing. Zinc oxide can easily immobilize proteins and hence offers a large group of enzyme based biosensor. Modification of the working electrode by introduction of these nanomaterials or combination of two/three of above nanomaterials together and forming a nanocomposite reflected the best results with excellent stability, reproducibility and enhanced sensitivity. Highly attractive electrochemical properties and electrocatalytic activity of these elite nanomaterials have facilitated achievement of enhanced signal amplification needed for the construction of ultrasensitive electrochemical affinity biosensors for detection of glucose, cholesterol, Escherichia coli, influenza virus, cancer, human papillomavirus, dopamine, glutamic acid, IgG, IgE, uric acid, ascorbic acid, acetlycholine, cortisol, cytosome, sequence specific DNA and amino acids. Recent researches for bedside biosensors are also discussed.

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

    PubMed

    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.

  19. Antibacterial activity of root canal filling materials for primary teeth: zinc oxide and eugenol cement, Calen paste thickened with zinc oxide, Sealapex and EndoREZ.

    PubMed

    Queiroz, Alexandra Mussolino de; Nelson-Filho, Paulo; Silva, Léa Assed Bezerra da; Assed, Sada; Silva, Raquel Assed Bezerra da; Ito, Izabel Yoko

    2009-01-01

    This study evaluated in vitro the antibacterial activity of 4 root canal filling materials for primary teeth - zinc oxide and eugenol cement (ZOE), Calen paste thickened with zinc oxide (Calen/ZO), Sealapex sealer and EndoREZ sealer - against 5 bacterial strains commonly found in endodontic infections (Kocuria rhizophila, Enterococcus faecalis, Streptococcus mutans, Escherichia coli and Staphylococcus aureus) using the agar diffusion test (agar-well technique). Calen paste, 1% chlorhexidine digluconate (CHX) and distilled water served as controls. Seven wells per dish were made at equidistant points and immediately filled with the test and control materials. After incubation of the plates at 37 degrees C for 24 h, the diameter of the zones of bacterial growth inhibition produced around the wells was measured (in mm) with a digital caliper under reflected light. Data were analyzed statistically by analysis of variance and Tukey's post-hoc test (alpha=0.05). There were statistically significant differences (p<0.0001) among the zones of bacterial growth inhibition produced by the different materials against all target microorganisms. K. rhizophila was inhibited more effectively (p<0.05) by ZOE, while Calen/ZO had its highest antibacterial activity against E. faecalis (p<0.05). S. mutans was inhibited by Calen/ZO, Sealapex and ZOE in the same intensity (p>0.05). E. coli was inhibited more effectively (p<0.05) by ZOE, followed by Calen/ZO and Sealapex. Calen/ZO and ZOE were equally effective (p>0.05) against S. aureus, while Sealapex had the lowest antibacterial efficacy (p<0.05) against this microorganism. EndoREZ presented antibacterial activity only against K. rhizophila and S. aureus. The Calen paste and Calen/ZO produced larger zones of inhibition than 1% CHX when the marker microorganism was E faecalis. In conclusion, the in vitro antibacterial activity of the 4 root canal filling materials for primary teeth against bacterial strains commonly found in endodontic

  20. Growth, intermixing, and surface phase formation for zinc tin oxide nanolaminates produced by atomic layer deposition

    SciTech Connect

    Hägglund, Carl; Grehl, Thomas; Brongersma, Hidde H.; Tanskanen, Jukka T.; Mullings, Marja N.; Mackus, Adriaan J. M.; MacIsaac, Callisto; Bent, Stacey Francine; Yee, Ye Sheng; Clemens, Bruce M.

    2016-03-15

    A broad and expanding range of materials can be produced by atomic layer deposition at relatively low temperatures, including both oxides and metals. For many applications of interest, however, it is desirable to grow more tailored and complex materials such as semiconductors with a certain doping, mixed oxides, and metallic alloys. How well such mixed materials can be accomplished with atomic layer deposition requires knowledge of the conditions under which the resulting films will be mixed, solid solutions, or laminated. The growth and lamination of zinc oxide and tin oxide is studied here by means of the extremely surface sensitive technique of low energy ion scattering, combined with bulk composition and thickness determination, and x-ray diffraction. At the low temperatures used for deposition (150 °C), there is little evidence for atomic scale mixing even with the smallest possible bilayer period, and instead a morphology with small ZnO inclusions in a SnO{sub x} matrix is deduced. Postannealing of such laminates above 400 °C however produces a stable surface phase with a 30% increased density. From the surface stoichiometry, this is likely the inverted spinel of zinc stannate, Zn{sub 2}SnO{sub 4}. Annealing to 800 °C results in films containing crystalline Zn{sub 2}SnO{sub 4}, or multilayered films of crystalline ZnO, Zn{sub 2}SnO{sub 4}, and SnO{sub 2} phases, depending on the bilayer period.

  1. Competing weak localization and weak antilocalization in amorphous indium-gallium-zinc-oxide thin-film transistors

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Hsiang; Lyu, Syue-Ru; Heredia, Elica; Liu, Shu-Hao; Jiang, Pei-hsun; Liao, Po-Yung; Chang, Ting-Chang; Chen, Hua-Mao

    2017-01-01

    We have investigated the gate-voltage dependence and the temperature dependence of the magnetoconductivity of amorphous indium-gallium-zinc-oxide thin-film transistors. A weak-localization feature is observed at small magnetic fields on top of an overall negative magnetoconductivity at higher fields. An intriguing controllable competition between weak localization and weak antilocalization is observed by tuning the gate voltage or by varying the temperature. Our findings reflect controllable quantum interference competition in the electron systems in amorphous indium-gallium-zinc-oxide thin-film transistors.

  2. Zinc Oxide Nanoparticles for Selective Destruction of Tumor Cells and Potential for Drug Delivery Applications

    PubMed Central

    Rasmussen, John W.; Martinez, Ezequiel; Louka, Panagiota; Wingett, Denise G.

    2010-01-01

    Importance of the field Metal oxide nanoparticles, including zinc oxide, are versatile platforms for biomedical applications and therapeutic intervention. There is an urgent need to develop new classes of anticancer agents, and recent studies demonstrate that ZnO nanomaterials hold considerable promise. Areas covered in this review This review analyzes the biomedical applications of metal oxide and ZnO nanomaterials under development at the experimental, preclinical, and clinical levels. A discussion regarding the advantages, approaches, and limitations surrounding the use of metal oxide nanoparticles for cancer applications and drug delivery is presented. The scope of this article is focused on ZnO, and other metal oxide nanomaterial systems, and their proposed mechanisms of cytotoxic action, as well as current approaches to improve their targeting and cytotoxicity against cancer cells. Take home message Through a better understanding of the mechanisms of action and cellular consequences resulting from nanoparticles interactions with cells, the inherent toxicity and selectivity of ZnO nanoparticles against cancer may be further improved to make them attractive new anti-cancer agents. PMID:20716019

  3. Effects of Sodium Citrate on the Ammonium Sulfate Recycled Leaching of Low-Grade Zinc Oxide Ores

    NASA Astrophysics Data System (ADS)

    Yang, Kun; Li, Shi-wei; Zhang, Li-bo; Peng, Jin-hui; Ma, Ai-yuan; Wang, Bao-bao

    2016-03-01

    The effects of sodium citrate on ammonium sulfate recycled leaching of low-grade zinc oxide ores were studied. By applying various kinds of detection and analysis techniques such as chemical composition analysis, chemical phase method, scanning electron microscopy and energy dispersive spectrum (SEM/EDS), X-ray diffraction (XRD) and Fourier-transforming infrared spectrum (FT-IR), zinc raw ore, its leaching slag and the functional mechanism of sodium citrate were investigated. Based on a comprehensive analysis, it can be concluded that in contrast to hemimorphite (Zn4Si2O7(OH)2 · H2O), amorphous smithsonite (ZnCO3) and zinc silicate (Zn2SiO4) prove to be refractory phases under ammonium sulfate leaching, while sodium citrate has a better chelating action with the refractory phases, resulting in a higher zinc leaching rate. Under conditions of [NH3]/[NH3]T molar ratio being 0.5, [NH3]T being 7.5 mol/L, [Na3C6H5O7] being 0.2 mol/L, S/L ratio being 1:5, temperature being 303 K, holding time being 1 h in each of the two stages, and stirring rate being 300 rpm, the leaching rate of zinc reached 93.4%. In this article, sulfate ammonium recycled technology also reveals its unique advantage in processing low-grade zinc oxide ores accompanied by high silicon and high alkaline gangue.

  4. Nitric Oxide Ameliorates Zinc Oxide Nanoparticles Phytotoxicity in Wheat Seedlings: Implication of the Ascorbate–Glutathione Cycle

    PubMed Central

    Tripathi, Durgesh K.; Mishra, Rohit K.; Singh, Swati; Singh, Samiksha; Vishwakarma, Kanchan; Sharma, Shivesh; Singh, Vijay P.; Singh, Prashant K.; Prasad, Sheo M.; Dubey, Nawal K.; Pandey, Avinash C.; Sahi, Shivendra; Chauhan, Devendra K.

    2017-01-01

    The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fm and qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate–glutatione cycle (AsA–GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA–GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA–GSH cycle. PMID:28220127

  5. Nitric Oxide Ameliorates Zinc Oxide Nanoparticles Phytotoxicity in Wheat Seedlings: Implication of the Ascorbate-Glutathione Cycle.

    PubMed

    Tripathi, Durgesh K; Mishra, Rohit K; Singh, Swati; Singh, Samiksha; Vishwakarma, Kanchan; Sharma, Shivesh; Singh, Vijay P; Singh, Prashant K; Prasad, Sheo M; Dubey, Nawal K; Pandey, Avinash C; Sahi, Shivendra; Chauhan, Devendra K

    2017-01-01

    The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fm and qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate-glutatione cycle (AsA-GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA-GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA-GSH cycle.

  6. Controlling the structure and rheology of TEMPO-oxidized cellulose in zinc chloride aqueous suspensions for fabricating advanced nanopaper

    NASA Astrophysics Data System (ADS)

    Wang, Sha; Zhang, Xin; Hu, Liangbing; Briber, Robert; Wang, Howard; Zhong, Linxin

    Due to its abundance, low-cost, biocompatibility and renewability, cellulose has become an attractive candidate as a functional material for various advanced applications. A key to novel applications is the control of the structure and rheology of suspensions of fibrous cellulose. Among many different approaches of preparing cellulose suspensions, zinc chloride addition to aqueous suspensions is regarded an effective practice. In this study, effects of ZnCl2 concentration on TEMPO-oxidized cellulose (TOC) nanofiber suspensions have been investigated. Highly-transparent cellulose nanofiber suspension can be rapidly obtained by dissolving TOC in 65 wt.% zinc chloride aqueous solutions at room temperature, whereas a transparent zinc ion cross-linked TOC gel could be obtained with zinc chloride concentration as low as 10 wt. %. The structural and rheological characteristics of TOC/ZnCl2 suspensions have been measured to correlate to the performance of thetransparent and flexible nanocellulose paper subsequently produced via vacuum filtration or wet-casting processes.

  7. The reduction of graphene oxide by zinc powder to produce a zinc oxide-reduced graphene oxide hybrid and its superior photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Sarkar, Sanjit; Basak, Durga

    2013-03-01

    We have synthesized for the first time ZnO/rGO hybrids from metal zinc and GO using hydrothermal technique without adding further reducing agent. The photocatalytic property of ZnO-rGO reveals that the hybrid for 50 mg of GO has the highest activity, causing a 94% degradation of methyl orange compared to 70% by only ZnO. The consistent quenching and a gradual decrease in the decay life time of the emission at ˜500 nm as the rGO content increases indicates the interfacial charge transfer process between ZnO and rGO by the defect states responsible for green emission.

  8. Ultrafast modulation of the plasma frequency of vertically aligned indium tin oxide rods.

    PubMed

    Tice, Daniel B; Li, Shi-Qiang; Tagliazucchi, Mario; Buchholz, D Bruce; Weiss, Emily A; Chang, Robert P H

    2014-03-12

    Light-matter interaction at the nanoscale is of particular interest for future photonic integrated circuits and devices with applications ranging from communication to sensing and imaging. In this Letter a combination of transient absorption (TA) and the use of third harmonic generation as a probe (THG-probe) has been adopted to investigate the response of the localized surface plasmon resonances (LSPRs) of vertically aligned indium tin oxide rods (ITORs) upon ultraviolet light (UV) excitation. TA experiments, which are sensitive to the extinction of the LSPR, show a fluence-dependent increase in the frequency and intensity of the LSPR. The THG-probe experiments show a fluence-dependent decrease of the LSPR-enhanced local electric field intensity within the rod, consistent with a shift of the LSPR to higher frequency. The kinetics from both TA and THG-probe experiments are found to be independent of the fluence of the pump. These results indicate that UV excitation modulates the plasma frequency of ITO on the ultrafast time scale by the injection of electrons into, and their subsequent decay from, the conduction band of the rods. Increases to the electron concentration in the conduction band of ∼13% were achieved in these experiments. Computer simulation and modeling have been used throughout the investigation to guide the design of the experiments and to map the electric field distribution around the rods for interpreting far-field measurement results.

  9. Effect of Dietary Zinc Oxide on Morphological Characteristics, Mucin Composition and Gene Expression in the Colon of Weaned Piglets

    PubMed Central

    Liu, Ping; Pieper, Robert; Rieger, Juliane; Vahjen, Wilfried; Davin, Roger; Plendl, Johanna; Meyer, Wilfried; Zentek, Jürgen

    2014-01-01

    The trace element zinc is often used in the diet of weaned piglets, as high doses have resulted in positive effects on intestinal health. However, the majority of previous studies evaluated zinc supplementations for a short period only and focused on the small intestine. The hypothesis of the present study was that low, medium and high levels of dietary zinc (57, 164 and 2,425 mg Zn/kg from zinc oxide) would affect colonic morphology and innate host defense mechanisms across 4 weeks post-weaning. Histological examinations were conducted regarding the colonic morphology and neutral, acidic, sialylated and sulphated mucins. The mRNA expression levels of mucin (MUC) 1, 2, 13, 20, toll-like receptor (TLR) 2, 4, interleukin (IL)-1β, 8, 10, interferon-γ (IFN-γ) and transforming growth factor-β (TGF-β) were also measured. The colonic crypt area increased in an age-depending manner, and the greatest area was found with medium concentration of dietary zinc. With the high concentration of dietary zinc, the number of goblet cells containing mixed neutral-acidic mucins and total mucins increased. Sialomucin containing goblet cells increased age-dependently. The expression of MUC2 increased with age and reached the highest level at 47 days of age. The expression levels of TLR2 and 4 decreased with age. The mRNA expression of TLR4 and the pro-inflammatory cytokine IL-8 were down-regulated with high dietary zinc treatment, while piglets fed with medium dietary zinc had the highest expression. It is concluded that dietary zinc level had a clear impact on colonic morphology, mucin profiles and immunological traits in piglets after weaning. Those changes might support local defense mechanisms and affect colonic physiology and contribute to the reported reduction of post-weaning diarrhea. PMID:24609095

  10. Influence of dietary carbohydrate on zinc-deficiency-induced changes in oxidative defense mechanisms and tissue oxidative damage in rats.

    PubMed

    Kim, S H; Keen, C L

    1999-10-01

    The aim of this study was to determine the effect of dietary carbohydrate type on the expression of zinc (Zn) deficiency in rats with respect to tissue oxidative damage and defense mechanisms. Rats were fed diets containing adequate (+Zn) or low concentrations (-Zn) of Zn. Both fructose- and glucose-based diets were tested. Pair-fed controls were also studied to evaluate changes in the oxidative defense system which are secondary to Zn-deficiency-induced anorexia. Plasma and liver Zn concentrations and CuZn superoxide dismutase activities were lower in the -Zn rats than in the +Zn rats. Liver glutathione (GSH) and disulfide glutathione concentrations were higher in the -Zn rats than in the +Zn rats; this difference was most pronounced in the fructose groups. Liver and heart selenium glutathione peroxidase (Se-GSH-Px) activities were lower in the -Zn-fructose group than in the +Zn-fructose group. Liver Se-GSH-Px activity was higher in the fructose groups than in the glucose groups. Liver GSH reductase (GSH-Red) activity was lower in the -Zn-fructose group than in its control group. Liver glutamine synthetase activity was lower in the -Zn-glucose group and in the fructose groups than in the glucose control group. Liver thiobarbituric acid reactive substance (TBARS) production was similar among the groups. Collectively, these results support the concept that Zn deficiency can result in an impaired oxidant defense system. Based on the observation that pair-fed control animals also showed evidence of oxidative damage, we suggest that one factor that contributes to the effect of Zn deficiency is the reduction in caloric intake that occurs in these animals. Fructose feeding resulted in increased activities of several of the oxidant defense enzymes. Protein oxidative damage assessed by glutamine synthetase activity was increased by both Zn deficiency and fructose feeding.

  11. Properties of solid solutions, doped film, and nanocomposite structures based on zinc oxide

    NASA Astrophysics Data System (ADS)

    Lashkarev, G. V.; Shtepliuk, I. I.; Ievtushenko, A. I.; Khyzhun, O. Y.; Kartuzov, V. V.; Ovsiannikova, L. I.; Karpyna, V. A.; Myroniuk, D. V.; Khomyak, V. V.; Tkach, V. N.; Timofeeva, I. I.; Popovich, V. I.; Dranchuk, N. V.; Khranovskyy, V. D.; Demydiuk, P. V.

    2015-02-01

    A study of the properties of materials based on the wide bandgap zinc oxide semiconductor, which are promising for application in optoelectronics, photovoltaics and nanoplasmonics. The structural and optical properties of solid solution Zn1-xCdxO films with different cadmium content, are studied. The samples are grown using magnetron sputtering on sapphire backing. Low-temperature photoluminescence spectra revealed emission peaks associated with radiative recombination processes in those areas of the film that have varying amounts of cadmium. X-ray phase analysis showed the presence of a cadmium oxide cubic phase in these films. Theoretical studies of the solid solution thermodynamic properties allowed for a qualitative interpretation of the observed experimental phenomena. It is established that the growth of the homogeneous solid solution film is possible only at high temperatures, whereas regions of inhomogeneous composition can be narrowed through elastic deformation, caused by the mismatch of the film-backing lattice constants. The driving forces of the spinodal decomposition of the Zn1-xCdxO system are identified. Fullerene-like clusters of Znn-xCdxOn are used to calculate the bandgap and the cohesive energy of ZnCdO solid solutions. The properties of transparent conductive ZnO films, doped with Group III donor impurities (Al, Ga, In), are examined. It is shown that oxygen vacancies are responsible for the hole trap centers in the zinc oxide photoconductivity process. We also examine the photoluminescence properties of metal-ZnO nanocomposite structures, caused by surface plasmons.

  12. Intrinsic and interfacial effect of electrode metals on the resistive switching behaviors of zinc oxide films.

    PubMed

    Xue, W H; Xiao, W; Shang, J; Chen, X X; Zhu, X J; Pan, L; Tan, H W; Zhang, W B; Ji, Z H; Liu, G; Xu, X-H; Ding, J; Li, R-W

    2014-10-24

    Exploring the role of electrode metals on the resistive switching properties of metal electrode/oxide/metal electrode sandwiched structures provides not only essential information to understand the underlying switching mechanism of the devices, but also useful guidelines for the optimization of the switching performance. A systematic study has been performed to investigate the influence of electrodes on the resistive switching characteristics of zinc oxide (ZnO) films in this contribution, in terms of both the intrinsic and interfacial effects. It has been found that the low-resistance state resistances (Ω(LRS)) of all the investigated devices are below 50 Ω, which can be attributed to the formation of highly conductive channels throughout the ZnO films. On the other hand, the high-resistance state resistances (Ω(HRS)) depend on the electronegativity and ionic size of the employed electrode metals. Devices with electrode metals of high electronegativity and large ionic size possess high Ω(HRS) values, while those with electrode metals of low electronegativity and small ionic size carry low Ω(HRS) values. A similar trend of the set voltages has also been observed, while the reset voltages are all distributed in a narrow range close to ±0.5 V. Moreover, the forming voltages of the switching devices strongly depend on the roughness of the metal/ZnO and/or ZnO/metal interface. The present work provides essential information for better understanding the switching mechanism of zinc oxide based devices, and benefits the rational selection of proper electrode metals for the device performance optimization.

  13. Colorimetric cholesterol sensor based on peroxidase like activity of zinc oxide nanoparticles incorporated carbon nanotubes.

    PubMed

    Hayat, Akhtar; Haider, Waqar; Raza, Yousuf; Marty, Jean Louis

    2015-10-01

    A sensitive and selective colorimetric method based on the incorporation of zinc oxide nanoparticles (ZnO NPs) on the surface of carbon nanotubes (CNTs) was shown to posses synergistic peroxidase like activity for the detection of cholesterol. The proposed nanocomposite catalyzed the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) in the presence of hydrogen peroxide (H2O2) to produce a green colored product which can be monitored at 405 nm. H2O2 is the oxidative product of cholesterol in the presence of cholesterol oxidase. Therefore, the oxidation of cholesterol can be quantitatively related to the colorimetric response by combining these two reactions. Under the optimal experimental conditions, the colorimetric response was proportional to the concentration of cholesterol in the range of 0.5-500 nmol/L, with a detection limit of 0.2 nmol/L. The applicability of the proposed assays was demonstrated for the determination of cholesterol in milk powder samples with good recovery results.

  14. Role of water temperature in the fate and transport of zinc oxide nanoparticles in aquatic environment

    NASA Astrophysics Data System (ADS)

    Majedi, Seyed Mohammad; Lee, Hian Kee; Kelly, Barry C.

    2013-04-01

    The influence of water temperature on the aggregation and dissolution kinetics of zinc oxide nanoparticles (ZnO NPs) (mean diameter ~40 nm) was investigated. Samples of 100 mg.L-1 ZnO NPs were incubated at 15, 25 and 35 °C, similar to the surface temperature of cold freshwater, temperate estuarine, and tropical/sub-tropical coastal marine ecosystems, respectively. The natural organic matter (NOM) content, pH, electrolyte type, and ionic strength (IS), were adjusted on the basis of the water chemistries of typical aqueous systems. Specifically, the time-dependent hydrodynamic diameters (HDDs) and sedimentation plots were obtained over the first 3 h and after 24 h using time-resolved dynamic light scattering (TR-DLS) and UV-visible spectroscopy, respectively. The settling distance was further modeled for the aggregates with various HDDs according to the Stokes' sedimentation equation. The dissolution kinetics was studied over the first 12 h and after 48 h in term of percentage of released zinc ions. The results showed that the HDD increased at elevated temperatures, termed as temperature-induced aggregation, while dissolution was reduced. The aggregation at higher temperatures further hindered the dissolution due to the decrease in the surface area of the NPs. We express this process as "aggregate-suppressed dissolution". The maximum aggregation was reached in the tropical coastal marine environment with the HDD >3 μm, and the released zinc ion of 9.2% was obtained in the cold freshwater. Based on the results, the aggregation rate of 1.57 nm.s-1 was estimated for the former, and the dissolution rate of 7.44 × 10-5 mol.L-1.h-1 was calculated for the latter, respectively. The predicted values successfully fitted to genuine water samples (<26% deviation). This study provides useful data for environmental risk assessment of exposure of ZnO NPs to water column and benthic organisms.

  15. Sonochemical synthesis and characterization of three nano zinc(II) coordination polymers; Precursors for preparation of zinc(II) oxide nanoparticles.

    PubMed

    Marandi, Farzin; Hashemi, Lida; Morsali, Ali; Krautscheid, Harald

    2016-09-01

    Nanostructures of three Zinc(II) coordination polymers, [Zn(NNO)2(H2O)4]n (1), [Zn(PNNO)2(H2O)2]n (2) and [Zn(H2O)6]·(INNO)2 (3) {NNO: Nicotinic acid N-oxide, PNNO: Picolinic acid N-oxide and INNO: Isonicotinic acid N-oxide}, have been synthesized by a sonochemical process and reaction of ligands with Zn(CH3COO)2. The Zinc(II) oxide nano-particles have been synthesized from thermolysis of [Zn(NNO)2(H2O)4]n (1), [Zn(PNNO)2(H2O)2]n (2) and [Zn(H2O)6]·(INNO)2 (3) at two different methods (with surfactant and without surfactant) and two temperatures (200 and 600°C). The ZnO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Comparison of the SEM images of ZnO nano-particles at two different methods and temperatures shows that higher temperature results in an increasing of agglomeration and thus small and spherical ZnO particles with good separation were produced by thermolysis of compounds at 200°C and by use of surfactant.

  16. Characteristics of zinc oxide nanorod array/titanium oxide film heterojunction prepared by aqueous solution deposition

    NASA Astrophysics Data System (ADS)

    Lee, Ming-Kwei; Hong, Min-Hsuan; Li, Bo-Wei

    2016-07-01

    The characteristics of a ZnO nanorod array/TiO2 film heterojunction were investigated. A TiO2 film was prepared on glass by aqueous solution deposition with precursors of ammonium hexafluorotitanate and boric acid at 40 °C. Then, a ZnO seed layer was prepared on a TiO2 film/glass substrate by RF sputtering. A vertically oriented ZnO nanorod array was grown on a ZnO seed layer/TiO2 film/glass substrate by aqueous solution deposition with precursors of zinc nitrate and hexamethylenetetramine (HMT) at 70 °C. After thermal annealing in N2O ambient at 300 °C, this heterojunction used as an oxygen gas sensor shows much better rise time, decay time, and on/off current ratio than as-grown and annealed ZnO nanorods.

  17. Sol-gel zinc oxide humidity sensors integrated with a ring oscillator circuit on-a-chip.

    PubMed

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2014-10-28

    The study develops an integrated humidity microsensor fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated humidity sensor consists of a humidity sensor and a ring oscillator circuit on-a-chip. The humidity sensor is composed of a sensitive film and branch interdigitated electrodes. The sensitive film is zinc oxide prepared by sol-gel method. After completion of the CMOS process, the sensor requires a post-process to remove the sacrificial oxide layer and to coat the zinc oxide film on the interdigitated electrodes. The capacitance of the sensor changes when the sensitive film adsorbs water vapor. The circuit is used to convert the capacitance of the humidity sensor into the oscillation frequency output. Experimental results show that the output frequency of the sensor changes from 84.3 to 73.4 MHz at 30 °C as the humidity increases 40 to 90%RH.

  18. Sol-Gel Zinc Oxide Humidity Sensors Integrated with a Ring Oscillator Circuit On-a-Chip

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2014-01-01

    The study develops an integrated humidity microsensor fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated humidity sensor consists of a humidity sensor and a ring oscillator circuit on-a-chip. The humidity sensor is composed of a sensitive film and branch interdigitated electrodes. The sensitive film is zinc oxide prepared by sol-gel method. After completion of the CMOS process, the sensor requires a post-process to remove the sacrificial oxide layer and to coat the zinc oxide film on the interdigitated electrodes. The capacitance of the sensor changes when the sensitive film adsorbs water vapor. The circuit is used to convert the capacitance of the humidity sensor into the oscillation frequency output. Experimental results show that the output frequency of the sensor changes from 84.3 to 73.4 MHz at 30 °C as the humidity increases 40 to 90 %RH. PMID:25353984

  19. Osteogenic activity and antibacterial effect of zinc oxide/carboxylated graphene oxide nanocomposites: Preparation and in vitro evaluation.

    PubMed

    Chen, Junyu; Zhang, Xin; Cai, He; Chen, Zhiqiang; Wang, Tong; Jia, Lingling; Wang, Jian; Wan, Qianbing; Pei, Xibo

    2016-11-01

    The aim of this study was to prepare nanocomposites of carboxylated graphene oxide (GO-COOH) sheets decorated with zinc oxide (ZnO) nanoparticles (NPs) and investigate their advantages in the field of bone tissue engineering. First, ZnO/GO-COOH nanocomposites were synthesized by facile reactions, including the carboxylation of graphene oxide (GO) and the nucleation of ZnO on GO-COOH sheets. The synthesized ZnO/GO-COOH nanocomposites were then characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and transmission electron microscopy (TEM). The biocompatibility, osteogenic activity and antibacterial effect of ZnO/GO-COOH nanocomposites were further investigated. In the nanocomposites, ZnO nanoparticles with a size of approximately 12nm were uniformly decorated on GO-COOH sheets. Compared with GO-COOH and the control group, ZnO/GO-COOH nanocomposites significantly enhanced ALP activity, osteocalcin production and extracellular matrix mineralization as well as up-regulated osteogenic-related genes (ALP, OCN, and Runx2) in MG63 osteoblast-like cells. Moreover, ZnO/GO-COOH nanocomposites had an antibacterial effect against Streptococcus mutans. These results indicated that ZnO/GO-COOH nanocomposites exhibited both osteogenic activity and antibacterial effect and had great potential for designing new biomaterials in the field of bone tissue engineering.

  20. Mineral filters in sunscreen products--comparison of the efficacy of zinc oxide and titanium dioxide by in vitro method.

    PubMed

    Couteau, C; Alami, S; Guitton, M; Paparis, E; Coiffard, L J M

    2008-01-01

    European legislation currently authorizes 26 sun filters among which, there is only one mineral filter: titanium dioxide. In the United States, two mineral filters are authorized: titanium dioxide in a maximum dose of 25% and zinc oxide. Zinc oxide is authorized in Europe, but its concentration level is not limited. A large number of commercial products are containing one of these mineral filters. The difference between these products lies in the percentage of the active substance, the way they are incorporated into the final product and the size of the primary particles. Depending on the ingredient used, there is a large variation in efficacy. The efficacy of the products tested was determined by an in vitro method using a spectrophotometer equipped with an integration sphere. Titanium dioxide was thus seen to be much more effective than zinc oxide; indeed no commercial form of zinc oxide tested can give a sun protection factor (SPF) higher than 10 at its maximum dose of use, unlike titanium dioxide which in its coated form (coated with alumina and with stearic acid, amongst others) gives a SPF of 38. This study has also allowed us to dispel the theory that talc--a raw material which has been used empirically for years in foundation in the belief that it has photoprotective effects--has an effect against sun rays. Talc proved to be particularly ineffective, as when it is used at a level of 25%, it only gives a totally negligible SPF of one unit.

  1. Antimicrobial Efficacy of Zinc Oxide Quantum Dots Against Listeria Monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc oxide quantum dots (ZnO QDs) in a powder form, a ZnO-polystyrene (PS) film form and a polyvinylprolidone capped ZnO (ZnO-PVP) gel form were prepared and their antibacterial activities against foodborne pathogenic Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7 in cul...

  2. Functional finishing of cotton fabrics using zinc oxide soluble starch nanocomposites

    NASA Astrophysics Data System (ADS)

    Vigneshwaran, Nadanathangam; Kumar, Sampath; Kathe, A. A.; Varadarajan, P. V.; Prasad, Virendra

    2006-10-01

    Zinc oxide-soluble starch nanocomposites (nano-ZnO) synthesized using water as a solvent and soluble starch as a stabilizer is impregnated onto cotton fabrics to impart antibacterial and UV-protection functions. Nano-ZnO synthesized by reacting zinc nitrate with sodium hydroxide in the presence of soluble starch absorbed strongly at 361 nm due to the quantum confinement effect. The average size of ZnO nanoparticles is estimated to be 38 ± 3 nm using a transmission electron microscope (TEM); this was confirmed by x-ray diffraction analysis and the effective mass approximation method. The starch content in synthesized nano-ZnO was estimated to be 37.57% using thermo-gravimetric analysis. The nano-ZnO impregnated cotton fabrics showed excellent antibacterial activity against two representative bacteria, Staphylococcus aureus (Gram positive) and Klebsiella pneumoniae (Gram negative). Also, nano-ZnO impregnation enhanced the protection of cotton fabrics against UV radiation in comparison with the untreated cotton fabrics.

  3. Dissolution kinetics of macronutrient fertilizers coated with manufactured zinc oxide nanoparticles.

    PubMed

    Milani, Narges; McLaughlin, Mike J; Stacey, Samuel P; Kirby, Jason K; Hettiarachchi, Ganga M; Beak, Douglas G; Cornelis, Geert

    2012-04-25

    The solubility of Zn in Zn fertilizers plays an important role in the agronomic effectiveness of the fertilizer. On the basis of thermodynamics, zinc oxide (ZnO) nanoparticles (NPs) should dissolve faster and to a greater extent than bulk ZnO particles (equivalent spherical diameter >100 nm). These novel solubility features of ZnO NPs might be exploited to improve the efficiency of Zn fertilizers. In this study, we compared the Zn solubility and dissolution kinetics of ZnO nanoparticles and bulk ZnO particles coated onto two selected granular macronutrient fertilizers, urea and monoammonium phosphate (MAP). The main Zn species on coated MAP and urea granules were zinc ammonium phosphate and ZnO, respectively. Coated MAP granules showed greater Zn solubility and faster dissolution rates in sand columns compared to coated urea granules, which may be related to pH differences in the solution surrounding the fertilizer granules. The kinetics of Zn dissolution was not affected by the size of the ZnO particles applied for coating of either fertilizer type, possibly because solubility was controlled by formation of the same compounds irrespective of the size of the original ZnO particles used for coating.

  4. Determination of zinc oxide nanoparticles toxicity in root growth in wheat (Triticum aestivum L.) seedlings.

    PubMed

    Prakash, Meppaloor G; Chung, Ill Min

    2016-09-01

    The effect of zinc oxide nanoparticles (ZnONPs) was studied in wheat (Triticum aestivum L.) seedlings under in vitro exposure conditions. To avoid precipitation of nanoparticles, the seedlings were grown in half strength semisolid Murashige and Skoog medium containing 0, 50, 100, 200, 400 and 500 mg L(-1) of ZnONPs. Analysis of zinc (Zn) content showed significant increase in roots. In vivo detection using fluorescent probe Zynpyr-1 indicated accumulation of Zn in primary and lateral root tips. All concentrations of ZnONPs significantly reduced root growth. However, significant decrease in shoot growth was observed only after exposure to 400 and 500 mg L(-1) of ZnONPs. The reactive oxygen species and lipid peroxidation levels significantly increased in roots. Significant increase in cell-wall bound peroxidase activity was observed after exposure to 500 mg L(-1) of ZnONPs. Histochemical staining with phloroglucinol-HCl showed lignification of root cells upon exposure to 500 mg L(-1) of ZnONPs. Treatment with propidium iodide indicated loss of cell viability in root tips of wheat seedlings. These results suggest that redox imbalances, lignification and cell death has resulted in reduction of root growth in wheat seedlings exposed to ZnONPs nanoparticles.

  5. Continuous synthesis of zinc oxide nanoparticles in a microfluidic system for photovoltaic application

    NASA Astrophysics Data System (ADS)

    Kang, Hyun Wook; Leem, Juyoung; Yoon, Sang Youl; Sung, Hyung Jin

    2014-02-01

    This study describes the synthesis of zinc oxide nanoparticles (ZnO NPs) using a microfluidic system. A continuous and efficient synthetic process was developed based on a microfluidic reactor in which was implemented a time pulsed mixing method that had been optimized using numerical simulations and experimental methods. Numerical simulations revealed that efficient mixing conditions could be obtained over the frequency range 5-15 Hz. This system used ethanol solutions containing 30 mM sodium hydroxide (NaOH) or 10 mM dehydrated zinc acetate (Zn(OAc)2) under 5 Hz pulsed conditions, which provided the optimal mixing performance conditions. The ZnO NPs prepared using the microfluidic synthetic system or batch-processed system were validated by several analytical methods, including transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), UV/VIS NIR and zeta (ζ) potential analysis. Bulk-heterojunction organic photovoltaic cells were fabricated with the synthesized ZnO NPs to investigate the practicability and compared with batch-process synthesized ZnO NPs. The results showed that microfluidic synthesized ZnO NPs had good preservability and stability in working solution and the synthetic microfluidic system provided a low-cost, environmentally friendly approach to the continuous production of ZnO NPs.

  6. Significant Enhancement in the Conductivity of Al-Doped Zinc Oxide thin Films for TCO Application

    NASA Astrophysics Data System (ADS)

    Mohite, R. M.; Ansari, J. N.; Roy, A. S.; Kothawale, R. R.

    2016-03-01

    Nanostructured Al-doped Zinc oxide (ZnO) thin films were deposited on glass substrate by chemical bath deposition (CBD) using aqueous zinc nitrate solution and subjected for different characterizations. Effect of Al3+ substitution on the properties of ZnO annealed at 400∘C was studied by XRD and UV-Vis for structural studies, SEM and TEM for surface morphology and DC four probe resistivity measurements for electrical properties. Al3+ substitution does not influence the morphology and well-known peaks related to wurtzite structure of ZnO. Electron microscopy (SEM and TEM) confirms rod shaped Al-doped ZnO nanocrystals with average width of 50nm. The optical band gap determined by UV-Visible spectroscopy was found to be in the range 3.37eV to 3.44eV. An EPR spectrum of AZO reveals peak at g=1.96 is due to shallow donors Zn interstitial. The DC electrical resistivity measurements of Al-doped ZnO show a minimum resistivity of 3.77×10-2Ω-cm. Therefore, these samples have potential use in n-type window layer in optoelectronic devices, organic solar cells, photonic crystals, photo-detectors, light emitting diodes (LEDs), gas sensors and chemical sensors.

  7. Effect of hydroxylamine hydrochloride on the floral decoration of zinc oxide synthesized by solution method

    NASA Astrophysics Data System (ADS)

    Wahab, Rizwan; Ansari, S. G.; Kim, Young Soon; Khang, Gilson; Shin, Hyung-Shik

    2008-01-01

    Effect of the structure-directing agent on the floral (depicting flower) morphological variation of ZnO is systematically studied and presented here. Flowery decorated (resembling flower) zinc oxide structure composed of hexagonal nanorods (sharp tips and wider bases) was synthesized at 90 °C using zinc acetate dihydrate and sodium hydroxide at various concentrations of hydroxylamine hydrochloride for 12 h by solution method. Single crystalline nature with the wurtzite hexagonal phase remained unaltered with increasing concentration of hydroxylamine hydrochloride while the morphology changes from nanorod to plate like structure. Photoelectron spectroscopic measurement presented spectra close to the standard bulk ZnO, with an O 1s peak composed of surface adsorbed O sbnd H group, O 2- in the oxygen vacancies on ZnO structure and ZnO. At higher concentration (0.8 M), surface adsorbed O sbnd H group increases while other component decreases because of the changes in the nucleation and surface energy. Results clearly indicate that hydroxylamine hydrochloride works as a structure-directing agent without affecting other properties.

  8. Zinc(II) oxide solubility and phase behavior in aqueous sodium phosphate solutions at elevated temperatures

    SciTech Connect

    Ziemniak, S.E.; Jones, M.E.; Combs, K.E.S.

    1990-02-01

    A platinum-lined, flowing autoclave facility is used to investigate the solubility/phase behavior of zinc(II) oxide in aqueous sodium phosphate solutions at temperatures between 290 and 560 K. ZnO solubilities are observed to increase continuously with temperature and phosphate concentration. At higher phosphate concentrations, a solid phase transformation to NaZnPO{sub 4} is observed. NaZnPO{sub 4} solubilities are retrograde with temperature. The measured solubility behavior is examined via a Zn(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reaction equilibria are obtained from a least-squares analysis of the data. The existence of two new zinc(II) ion complexes is reported for the first time: Zn(OH){sub 2}(HPO{sub 4}){sup 2{minus}} and Zn(OH){sub 3}(H{sub 2}PO{sub 4}){sup 2{minus}}. A summary of thermochemical properties for species in the systems ZnO-H{sub 2}O and ZnO-Na{sub 2}O-P{sub 2}O{sub 5}-H{sub 2}O is also provided. 21 refs., 10 figs., 7 tabs.

  9. Continuous synthesis of zinc oxide nanoparticles in a microfluidic system for photovoltaic application.

    PubMed

    Kang, Hyun Wook; Leem, Juyoung; Yoon, Sang Youl; Sung, Hyung Jin

    2014-03-07

    This study describes the synthesis of zinc oxide nanoparticles (ZnO NPs) using a microfluidic system. A continuous and efficient synthetic process was developed based on a microfluidic reactor in which was implemented a time pulsed mixing method that had been optimized using numerical simulations and experimental methods. Numerical simulations revealed that efficient mixing conditions could be obtained over the frequency range 5-15 Hz. This system used ethanol solutions containing 30 mM sodium hydroxide (NaOH) or 10 mM dehydrated zinc acetate (Zn(OAc)2) under 5 Hz pulsed conditions, which provided the optimal mixing performance conditions. The ZnO NPs prepared using the microfluidic synthetic system or batch-processed system were validated by several analytical methods, including transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), UV/VIS NIR and zeta (ζ) potential analysis. Bulk-heterojunction organic photovoltaic cells were fabricated with the synthesized ZnO NPs to investigate the practicability and compared with batch-process synthesized ZnO NPs. The results showed that microfluidic synthesized ZnO NPs had good preservability and stability in working solution and the synthetic microfluidic system provided a low-cost, environmentally friendly approach to the continuous production of ZnO NPs.

  10. Synthesis and characterization of nanometric zinc oxide for a stationary phase in liquid chromatography

    NASA Astrophysics Data System (ADS)

    Gordillo-Delgado, F.; Soto-Barrera, C. C.; Plazas-Saldaña, J.

    2017-01-01

    The increasing demand for equipment to remove organic compounds in industry and research activity has led to evaluate nanometric zinc oxide (ZnO). In this work, we present the ZnO nanoparticles synthesis for reusing of discarded columns, as a low-cost alternative. The compound was obtained by sol-gel technique using zinc chloride and sodium hydroxide as precursors and a drying temperature of 169°C. An X-ray diffractometer was used to estimate the average particle size at 20.3±0.2nm the adsorption capacity was 0.0144L/g and the chemical resistance was tested with HCl and NaOH. The ZnO nanopowder was packed with 100psi pressure in an empty C-18 column cavity. The column packing resolution was evaluated using a high performance liquid chromatographer (HPLC-Thermo Scientific Dionex UltiMate 3000); using a caffeine standard, the following parameters were established: solvent flow: 1.2mL/min, average column temperature: 40°C, running time: 10 minutes, mobile phase acetonitrile-water composition (9:1). These results validate the potential of ZnO nanopowder as a column packing material in HPLC technique.

  11. Fluorine-doped zinc oxide thin films: influence of precursor flow rate on violet luminescence

    NASA Astrophysics Data System (ADS)

    Muthukumar, Anusha; Dakshnamoorthy, Arivuoli

    2015-06-01

    Fluorine-doped zinc oxide (FZO) thin films were deposited by the aerosol-assisted chemical vapor deposition method with variable precursor flow rates (0.5-2.5 ml/min). X-ray diffraction patterns revealed the polycrystalline hexagonal wurtzite structure of the derived FZO nanocrystalline thin films. Extensive crystallinity analysis of the film deposited at 1 ml/min was done by grazing incidence X-ray diffraction. Field emission scanning electron microscope images apparent the gradual evolution from spherical grains and hexagonal platelet like surface morphology with increased flow rate. Optical transparency and photoluminescence (PL) are strongly influenced by flow rate. PL intensity and transparency increase with decreased flow rate. The optical bandgap was tuned significantly by increase in flow rate and especially tuned the PL emission from violet to UV. High intense violet PL observed at flow rate of 1 ml/min and radiative transition of electrons from zinc vacancies level to the conduction band were found. Crystallinity, growth rate and roughness increase with increased flow rate.

  12. Simple mass production of zinc oxide nanostructures via low-temperature hydrothermal synthesis

    NASA Astrophysics Data System (ADS)

    Ghasaban, Samaneh; Atai, Mohammad; Imani, Mohammad

    2017-03-01

    The specific properties of zinc oxide (ZnO) nanoparticles have attracted much attention within the scientific community as a useful material for biomedical applications. Hydrothermal synthesis is known as a useful method to produce nanostructures with certain particle size and morphology however, scaling up the reaction is still a challenging task. In this research, large scale hydrothermal synthesis of ZnO nanostructures (60 g) was performed in a 5 l stainless steel autoclave by reaction between anionic (ammonia or sodium hydroxide) and cationic (zinc acetate dehydrate) precursors in low temperature. Hydrothermal reaction temperature and time were decreased to 115 °C and 2 or 6 h. In batch repetitions, the same morphologies (plate- and needle-like) with reproducible particle size were obtained. The nanostructures formed were analyzed by powder x-ray diffraction, Fourier-transform infrared spectroscopy, energy dispersive x-ray analysis, scanning electron microscopy and BET analysis. The nanostructures formed were antibacterially active against Staphylococcus aureus.

  13. A novel approach reveals that zinc oxide nanoparticles are bioavailable and toxic after dietary exposures

    USGS Publications Warehouse

    Croteau, M.-N.; Dybowska, A.D.; Luoma, S.N.; Valsami-Jones, E.

    2011-01-01

    If engineered nanomaterials are released into the environment, some are likely to end up associated with the food of animals due to aggregation and sorption processes. However, few studies have considered dietary exposure of nanomaterials. Here we show that zinc (Zn) from isotopically modified 67ZnO particles is efficiently assimilated by freshwater snails when ingested with food. The 67Zn from nano-sized 67ZnO appears as bioavailable as 67Zn internalized by diatoms. Apparent agglomeration of the zinc oxide (ZnO) particles did not reduce bioavailability, nor preclude toxicity. In the diet, ZnO nanoparticles damage digestion: snails ate less, defecated less and inefficiently processed the ingested food when exposed to high concentrations of ZnO. It was not clear whether the toxicity was due to the high Zn dose achieved with nanoparticles or to the ZnO nanoparticles themselves. Further study of exposure from nanoparticles in food would greatly benefit assessment of ecological and human health risks. ?? 2011 Informa UK, Ltd.

  14. Tailoring the optical and hydrophobic property of zinc oxide nanorod by coating with amorphous graphene

    NASA Astrophysics Data System (ADS)

    Pahari, D.; Das, N. S.; Das, B.; Chattopadhyay, K. K.; Banerjee, D.

    2016-09-01

    Zinc oxide (ZnO) nanorods were synthesized at room temperature on potassium permanganate activated silicon and glass substrate by simple chemical method using zinc acetate as precursor. To modify the surface energy of the as prepared ZnO thin films the samples were coated with amorphous graphene (a-G) synthesized by un-zipping of chemically synthesized amorphous carbon nanotubes (a-CNTs). All the pure and coated samples were characterized by x-ray diffraction, field emission scanning electron microscope, Raman spectroscopy, and Fourier transformed infrared spectroscopy. The roughness analysis of the as prepared samples was done by atomic force microscopic analysis. The detail optical properties of all the samples were studied with the help of a UV-Visible spectrophotometer. The surface energy of the as prepared pure and coated samples was calculated by measuring the contact angle of two different liquids. It is seen that the water repellence of ZnO nanorods got increased after they are being coated with a-Gs. Also even after UV irradiation the contact angle remain same unlike the case for the uncoated sample where the contact angle gets decreased significantly after UV irradiation. Existing Cassie-Wenzel model has been employed along with the Owen's approach to determine the different components of surface energy.

  15. Preparation of Zinc Oxide-Starch Nanocomposite and Its Application on Coating

    NASA Astrophysics Data System (ADS)

    Ma, Jinxia; Zhu, Wenhua; Tian, Yajun; Wang, Zhiguo

    2016-04-01

    A new production method of zinc oxide (ZnO)-starch nanocomposite was invented in this study. Starch was dissolved in zinc chloride (ZnCl2) solution (65 wt%) at 80 °C. Then, ZnO-starch nanocomposite was achieved when the pH of the solution was adjusted to 8.4 by NaOH solution (15 wt%). ZnO nanoparticles were also obtained when the generated ZnO-starch nanocomposite was calcined at 575 °C. The properties of ZnO-starch nanocomposite and ZnO nanoparticle were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the sizes of ZnO-starch composite and ZnO particle were 40-60 nm. UV blocking effect was observed from both ZnO-starch nanocomposite and ZnO nanoparticle. The ZnO-starch nanocomposite was used to directly coat the surface of plain paper with a laboratory paper coater. The surface strength and smoothness of paper were improved by the coating of ZnO-starch nanocomposite. The antibacterial property was also identified from the coated paper.

  16. Synthesis of supported silver nano-spheres on zinc oxide nanorods for visible light photocatalytic applications

    SciTech Connect

    Saoud, Khaled; Alsoubaihi, Rola; Bensalah, Nasr; Bora, Tanujjal; Bertino, Massimo; Dutta, Joydeep

    2015-03-15

    Highlights: • Synthesis of supported Ag NPs on ZnO nanorods using open vessel microwave reactor. • Use of the Ag/ZnO NPs as an efficient visible light photocatalyst. • Complete degradation of methylene blue in 1 h with 0.5 g/L Ag/ZnO NPs. - Abstract: We report the synthesis of silver (Ag) nano-spheres (NS) supported on zinc oxide (ZnO) nanorods through two step mechanism, using open vessel microwave reactor. Direct reduction of ZnO from zinc nitrates was followed by deposition precipitation of the silver on the ZnO nanorods. The supported Ag/ZnO nanoparticles were then characterized by electron microscopy, X-ray diffraction, FTIR, photoluminescence and UV–vis spectroscopy. The visible light photocatalytic activity of Ag/ZnO system was investigated using a test contaminant, methylene blue (MB). Almost complete removal of MB in about 60 min for doses higher than 0.5 g/L of the Ag/ZnO photocatalyst was achieved. This significant improvement in the photocatalytic efficiency of Ag/ZnO photocatalyst under visible light irradiation can be attributed to the presence of Ag nanoparticles on the ZnO nanoparticles which greatly enhances absorption in the visible range of solar spectrum enabled by surface plasmon resonance effect from Ag nanoparticles.

  17. Development of near-infrared fluorescent probes for nitric oxide and zinc ion

    NASA Astrophysics Data System (ADS)

    Kojima, Hirotatsu; Kiyose, Kazuki; Sasaki, Eita; Nishimatsu, Hiroaki; Hirata, Yasunobu; Nagano, Tetsuo

    2007-02-01

    In fluorescence imaging studies of biological mechanisms, cyanine dyes have been employed as fluorescent labels. In particular, tricarbocyanines have the advantage that light at their emission and absorption maxima in the near-infrared (NIR) region around 650-900 nm can penetrate deeply into tissues. We successfully developed two types of cyanine dyes whose fluorescence properties change upon specific reaction with nitric oxide (NO) or zinc ion. The mechanism of fluorescence modulation of the NO probes involves photoinduced electron transfer, and the fluorescent intensity can change at the same wavelengths. We synthesized a series of amine-substituted tricarbocyanines in order to examine the correlation between the electron-donating ability of the amine and the fluorescence peak wavelength. We found that changing the electron-donating ability of the amine substituent altered the absorption and emission wavelengths. Then, we synthesized dipicolylcyanine (DIPCY), consisting of tricarbocyanine as a fluorophore and dipicolylethylenediamine as a heavy metal chelator, and investigated its response to various heavy metal ions. DIPCY can work as a ratiometric fluorescent sensor for zinc ion. This fluorescence modulation of amine-substituted tricarbocyanines should be applicable to dual-wavelength measurement of various biomolecules or enzyme activities. Thus, we have established two mechanisms for modulating the fluorescence properties of cyanines.

  18. Chromium and Ruthenium-Doped Zinc Oxide Thin Films for Propane Sensing Applications

    PubMed Central

    Gómez-Pozos, Heberto; González-Vidal, José Luis; Torres, Gonzalo Alberto; Rodríguez-Baez, Jorge; Maldonado, Arturo; de la Luz Olvera, María; Acosta, Dwight Roberto; Avendaño-Alejo, Maximino; Castañeda, Luis

    2013-01-01

    Chromium and ruthenium-doped zinc oxide (ZnO:Cr) and (ZnO:Ru) thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III) acetylacetonate and Ruthenium (III) trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8) atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr) and ruthenium (Ru), the sensing characteristics of undoped ZnO films are reported as well. PMID:23482091

  19. Structure-property-composition relationships in doped zinc oxides: enhanced photocatalytic activity with rare earth dopants.

    PubMed

    Goodall, Josephine B M; Illsley, Derek; Lines, Robert; Makwana, Neel M; Darr, Jawwad A

    2015-02-09

    In this paper, we demonstrate the use of continuous hydrothermal flow synthesis (CHFS) technology to rapidly produce a library of 56 crystalline (doped) zinc oxide nanopowders and two undoped samples, each with different particle properties. Each sample was produced in series from the mixing of an aqueous stream of basic zinc nitrate (and dopant ion or modifier) solution with a flow of superheated water (at 450 °C and 24.1 MPa), whereupon a crystalline nanoparticle slurry was rapidly formed. Each composition was collected in series, cleaned, freeze-dried, and then characterized using analytical methods, including powder X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area measurement, X-ray photoelectron spectroscopy, and UV-vis spectrophotometry. Photocatalytic activity of the samples toward the decolorization of methylene blue dye was assessed, and the results revealed that transition metal dopants tended to reduce the photoactivity while rare earth ions, in general, increased the photocatalytic activity. In general, low dopant concentrations were more beneficial to having greater photodecolorization in all cases.

  20. Effects of nanoparticle zinc oxide on emotional behavior and trace elements homeostasis in rat brain.

    PubMed

    Amara, Salem; Slama, Imen Ben; Omri, Karim; El Ghoul, Jaber; El Mir, Lassaad; Rhouma, Khemais Ben; Abdelmelek, Hafedh; Sakly, Mohsen

    2015-12-01

    Over recent years, nanotoxicology and the potential effects on human body have grown in significance, the potential influences of nanosized materials on the central nervous system have received more attention. The aim of this study was to determine whether zinc oxide (ZnO) nanoparticles (NPs) exposure cause alterations in emotional behavior and trace elements homeostasis in rat brain. Rats were treated by intraperitoneal injection of ZnO NPs (20-30 nm) at a dose of 25 mg/kg body weight. Sub -: acute ZnO NPs treatment induced no significant increase in the zinc content in the homogenate brain. Statistically significant decreases in iron and calcium concentrations were found in rat brain tissue compared to control. However, sodium and potassium contents remained unchanged. Also, there were no significant changes in the body weight and the coefficient of brain. In the present study, the anxiety-related behavior was evaluated using the plus-maze test. ZnO NPs treatment modulates slightly the exploratory behaviors of rats. However, no significant differences were observed in the anxious index between ZnO NP-treated rats and the control group (p > 0.05). Interestingly, our results demonstrated minimal effects of ZnO NPs on emotional behavior of animals, but there was a possible alteration in trace elements homeostasis in rat brain.

  1. Structural and photoluminescence properties of terbium-doped zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Ningthoujam Surajkumar, Singh; Shougaijam Dorendrajit, Singh; Sanoujam Dhiren, Meetei

    2014-05-01

    We present in this paper a study of the structural and photoluminescence (PL) properties of terbium (Tb) doped zinc oxide (ZnO) nanoparticles synthesized by a simple low temperature chemical precipitation method, using zinc acetate and terbium nitrate in an isopropanol medium with diethanolamine (DEA) as the capping agent at 60 °C. The as-prepared samples were heat treated and the PL of the annealed samples were studied. The prepared nanoparticles were characterized with X-ray diffraction (XRD). The XRD patterns show the pattern of typical ZnO nanoparticles and correspond with the standard XRD pattern given by JCPDS card No. 36-1451, showing the hexagonal phase structure. The PL intensity was enhanced due to Tb3+ doping, and it decreased at higher concentrations of Tb3+ doping after reaching a certain optimum concentration. The PL spectra of Tb3+ doped samples exhibited blue, bluish green, and green emissions at 460 nm (5D3 - 7F3), 484 nm (5D4 - 7F6), and 530 nm (5D4 - 7F5), respectively, which were more intense than the emissions for the undoped ZnO sample. Based on the results, an energy level schematic diagram was proposed to explain the possible electron transition processes.

  2. Zinc oxide nanoparticles with incorporated silver: Structural, morphological, optical and vibrational properties

    NASA Astrophysics Data System (ADS)

    Mosquera, Edgar; Rojas-Michea, Carolina; Morel, Mauricio; Gracia, Francisco; Fuenzalida, Víctor; Zárate, Ramón A.

    2015-08-01

    Zinc oxide nanoparticles with different amounts of incorporated silver (ZnO:Ag; 0.6, 3, 6, and 9 at.% Ag) have been successfully synthesized by a simple sol gel method. The effect of Ag content on the properties of ZnO nanoparticles have been studied by various characterization techniques. The results from X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (RS) suggest that elemental silver is present as a second phase. The UV-visible absorption and photoluminescence (PL) properties of the samples were also studied. PL data at room temperature reveals a strong blue emission. In addition, Raman spectroscopy results indicate a very strong A1(LO) mode resulting from oxygen vacancies and zinc interstitials. A new local vibrational mode (LVM) at 480 cm-1 induced by silver can also be observed in the Raman spectra, suggesting silver incorporation into the ZnO lattice compensating the Zn vacancies, which is consistent with the XRD results.

  3. Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer

    SciTech Connect

    Chen, Dazheng; Zhang, Chunfu Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue

    2014-06-16

    Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C{sub 61} butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 °C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 °C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

  4. Visible-blind ultraviolet photodiode fabricated by UV oxidation of metallic zinc on p-Si

    SciTech Connect

    Zhang, Dongyuan; Uchida, Kazuo; Nozaki, Shinji

    2015-09-07

    A UV photodiode fabricated by the UV oxidation of a metallic zinc thin film on p-Si has manifested unique photoresponse characteristics. The electron concentration found by the Hall measurement was 3 × 10{sup 16 }cm{sup −3}, and such a low electron concentration resulted in a low visible photoluminescence. UV illumination enhances the oxidation at low temperatures and decreases the concentration of the oxygen vacancies. The I-V characteristic showed a good rectification with a four-order magnitude difference in the forward and reverse currents at 2 V, and its linear and frequency independent C{sup −2}–V characteristic confirmed an abrupt pn junction. The photoresponse showed a visible blindness with a responsivity ratio of UV and visible light as high as 100. Such a visible-blind photoresponse was attributed to the optimum thickness of the SiO{sub 2} formed on the Si surface during the UV oxidation at 400 °C. A lower potential barrier to holes at the ZnO/SiO{sub 2} interface facilitates Fowler-Nordheim tunneling of the photo-generated holes during the UV illumination, while a higher potential barrier to electrons efficiently blocks transport of the photo-generated electrons to the ZnO during the visible light illumination. The presence of oxide resulted in a slow photoresponse to the turn-on and off of the UV light. A detailed analysis is presented to understand how the photo-generated carriers contribute step by step to the photocurrent. In addition to the slow photoresponse associated with the SiO{sub 2} interfacial layer, the decay of the photocurrent was found extremely slow after turn-off of the UV light. Such a slow decay of the photocurrent is referred to as a persistent photoconductivity, which is caused by metastable deep levels. It is hypothesized that Zn vacancies form such a deep level, and that the photo-generated electrons need to overcome a thermal-energy barrier for capture. The ZnO film by the UV oxidation at 400 °C was found

  5. Brassinosteroid Ameliorates Zinc Oxide Nanoparticles-Induced Oxidative Stress by Improving Antioxidant Potential and Redox Homeostasis in Tomato Seedling

    PubMed Central

    Li, Mengqi; Ahammed, Golam J.; Li, Caixia; Bao, Xiao; Yu, Jingquan; Huang, Chunlei; Yin, Hanqin; Zhou, Jie

    2016-01-01

    In the last few decades use of metal-based nanoparticles (MNPs) has been increased significantly that eventually contaminating agricultural land and limiting crop production worldwide. Moreover, contamination of food chain with MNPs has appeared as a matter of public concern due to risk of potential health hazard. Brassinosteroid has been shown to play a critical role in alleviating heavy metal stress; however, its function in relieving zinc oxide nanoparticles (ZnO NPs)-induced phytotoxicity remains unknown. In this study, we investigated the potential role of 24-epibrassinolide (BR) in mitigating ZnO NPs-induced toxicity in tomato seedlings. Seedling growth, biomass production, and root activity gradually decreased, but Zn accumulation increased with increasing ZnO NPs concentration (10–100 mg/L) in growth media (½ MS). The augmentation of BR (5 nM) in media significantly ameliorated 50 mg/L ZnO NPs-induced growth inhibition. Visualization of hydrogen peroxide (H2O2), and quantification of H2O2 and malondialdehyde (MDA) in tomato roots confirmed that ZnO NPs induced an oxidative stress. However, combined treatment with BR and ZnO NPs remarkably reduced concentration of H2O2 and MDA as compared with ZnO NPs only treatment, indicating that BR supplementation substantially reduced oxidative stress. Furthermore, the activities of key antioxidant enzymes such as superoxide dismutase (SOD), catalase, ascorbate peroxidase and glutathione reductase were increased by combined treatment of BR and ZnO NPs compared with ZnO NPs only treatment. BR also increased reduced glutathione (GSH), but decreased oxidized glutathione (GSSG)] and thus improved cellular redox homeostasis by increasing GSH:GSSG ratio. The changes in relative transcript abundance of corresponding antioxidant genes such as Cu/Zn SOD, CAT1, GSH1, and GR1 were in accordance with the changes in those antioxidants under different treatments. More importantly, combined application of BR and ZnO NPs

  6. Photoluminescent zinc oxide polymer nanocomposites fabricated using picosecond laser ablation in an organic solvent

    NASA Astrophysics Data System (ADS)

    Wagener, Philipp; Faramarzi, Shamsolzaman; Schwenke, Andreas; Rosenfeld, Rupert; Barcikowski, Stephan

    2011-06-01

    Nanocomposites made of ZnO nanoparticles dispersed in thermoplastic polyurethane were synthesized using picosecond laser ablation of zinc in a polymer-doped solution of tetrahydrofuran. The pre-added polymer stabilizes the ZnO nanoparticles in situ during laser ablation by forming a polymer shell around the nanoparticles. This close-contact polymer shell has a layer thickness up to 30 nm. Analysis of ZnO polyurethane nanocomposites using optical spectroscopy, high resolution transmission electron microscopy and X-ray diffraction revealed that oxidized and crystalline ZnO nanoparticles were produced. Those nanocomposites showed a green photoluminescence emission centred at 538 nm after excitation at 350 nm, which should be attributed to oxygen defects generated during the laser formation mechanism of the monocrystalline nanoparticles. Further, the influence of pulse energy and polymer concentration on the production rate, laser fluence and energy-specific mass productivity was investigated.

  7. Zinc oxide (ZnO) nanoparticles as saturable absorber in passively Q-switched fiber laser

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Lee, C. S. J.; Ismail, M. A.; Ali, Z. A.; Reduan, S. A.; Ruslan, N. E.; Ismail, M. F.; Harun, S. W.

    2016-12-01

    We demonstrate a passively Q-switched erbium-doped fiber laser using zinc oxide (ZnO) nanoparticles thin film as saturable absorber (SA). ZnO exhibits high nonlinear optical response and fast recovery time, fulfilling the requirements of an ideal SA. The nonlinear optical absorption is characterised by modulation depth of 3.5% with saturation intensity of 0.016 MW cm-2. We insert the SA into the laser cavity and obtain stable Q-switched pulse whereby the repetition rate increases from 41.7 kHz to 77.2 kHz while the pulse width decreases from 9.6 μs to 3.0 μs as the pump power is increased from 60 mW to 360 mW. This result suggests that ZnO could be a promising SA for photonic applications.

  8. Synthesis of zinc oxide nanostructures catalytically active in the optical range without irradiation

    NASA Astrophysics Data System (ADS)

    Kasumov, M. M.

    2012-09-01

    A technique for synthesizing catalytically active zinc oxide-based nanostructures is described. The synthesis product represents a blue-gray powder. When it is introduced into a water solution of methyl orange the latter bleaches out both under daylight and in the dark. The activity of the material is measured by the Kubelka-Munk formula in the wavelength range 0.3-1.8 μm. As follows from X-ray phase analysis data, the synthesized material is a composite consisting of hexagonal structures with the parameters ZnO [ a: 3.2491, c: 5.2046] and Zn [ a: 2.6639, c: 4.9397]. A mechanism underlying the formation of a ZnO-Zn nanocomposite is suggested.

  9. Ionic liquid gating reveals trap-filled limit mobility in low temperature amorphous zinc oxide

    NASA Astrophysics Data System (ADS)

    Bubel, S.; Meyer, S.; Kunze, F.; Chabinyc, M. L.

    2013-10-01

    In low-temperature solution processed amorphous zinc oxide (a-ZnO) thin films, we show the thin film transistor (TFT) characteristics for the trap-filled limit (TFL), when the quasi Fermi energy exceeds the conduction band edge and all tail-states are filled. In order to apply gate fields that are high enough to reach the TFL, we use an ionic liquid tape gate. Performing capacitance voltage measurements to determine the accumulated charge during TFT operation, we find the TFL at biases higher than predicted by the electronic structure of crystalline ZnO. We conclude that the density of states in the conduction band of a-ZnO is higher than in its crystalline state. Furthermore, we find no indication of percolative transport in the conduction band but trap assisted transport in the tail-states of the band.

  10. Indium Zinc Oxide Mediated Wafer Bonding for III-V/Si Tandem Solar Cells

    SciTech Connect

    Tamboli, Adele C.; Essig, Stephanie; Horowitz, Kelsey A. W.; Woodhouse, Michael; van Hest, Maikel F. A. M.; Norman, Andrew G.; Steiner, Myles A.; Stradins, Paul

    2015-06-14

    Silicon-based tandem solar cells are desirable as a high efficiency, economically viable approach to one sun or low concentration photovoltaics. We present an approach to wafer bonded III-V/Si solar cells using amorphous indium zinc oxide (IZO) as an interlayer. We investigate the impact of a heavily doped III-V contact layer on the electrical and optical properties of bonded test samples, including the predicted impact on tandem cell performance. We present economic modeling which indicates that the path to commercial viability for bonded cells includes developing low-cost III-V growth and reducing constraints on material smoothness. If these challenges can be surmounted, bonded tandems on Si can be cost-competitive with incumbent PV technologies, especially in low concentration, single axis tracking systems.

  11. Red Fluorescent Zinc Oxide Nanoparticle: A Novel Platform for Cancer Targeting

    PubMed Central

    Hong, Hao; Wang, Fei; Zhang, Yin; Graves, Stephen A.; Eddine, Savo Bou Zein; Yang, Yunan; Theuer, Charles P.; Nickles, Robert J.; Wang, Xudong; Cai, Weibo

    2015-01-01

    Multifunctional zinc oxide (ZnO) nanoparticles (NPs) with well-integrated multimodality imaging capacities have generated increasing research interest in the last decade. However, limited progress has been made in developing ZnO NP-based multimodality tumor-imaging agents. Here we developed novel red fluorescent ZnO NPs and described the successful conjugation of 64Cu (t1/2 = 12.7 h) and TRC105, a chimeric monoclonal antibody against CD105, to these ZnO NPs via well-developed surface engineering procedures. The produced dual-modality ZnO NPs were readily applicable for positron emission tomography (PET) imaging and fluorescence imaging of the tumor vasculature. Their pharmacokinetics and tumor-targeting efficacy/specificity in mice bearing murine breast 4T1 tumor were thoroughly investigated. ZnO NPs with dual-modality imaging properties can serve as an attractive candidate for future cancer theranostics. PMID:25607242

  12. Synthesis and characterization of zinc oxide nanoparticles: application to textiles as UV-absorbers

    NASA Astrophysics Data System (ADS)

    Becheri, Alessio; Dürr, Maximilian; Lo Nostro, Pierandrea; Baglioni, Piero

    2008-04-01

    We report the synthesis and characterization of nanosized zinc oxide particles and their application on cotton and wool fabrics for UV shielding. The nanoparticles were produced in different conditions of temperature (90 or 150 °C) and reacting medium (water or 1,2-ethanediol). A high temperature was necessary to obtain small monodispersed particles. Fourier transformed infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray powder diffractometry (XRD) were used to characterize the nanoparticles composition, their shape, size and crystallinity. The specific surface area of the dry powders was also determined. ZnO nanoparticles were then applied to cotton and wool samples to impart sunscreen activity to the treated textiles. The effectiveness of the treatment was assessed through UV-Vis spectrophotometry and the calculation of the ultraviolet protection factor (UPF). Physical tests (tensile strength and elongation) were performed on the fabrics before and after the treatment with ZnO nanoparticles.

  13. Synthesis and characterization of zinc-molybdenum oxide photocatalysts using an electrochemical-thermal process

    NASA Astrophysics Data System (ADS)

    Goveas, J. J.; Gonsalves, R. A.; Rao, P.; Pinto, R.

    2016-05-01

    Dyes act as major pollutants in water and can be degraded by photocatalysis. This paper establishes the role of electrochemically generated nanostructures of Zinc-Molybdenum oxides (ZMO) as photocatalysts by degrading EBT (Eriochrome Black- T) taken as a model pollutant under UV light. A facile, rapid and low cost process to synthesize these nanostructures (ZMO) is presented. Various factors that affect the synthesis and photocatalytic activity of these nanostructures are discussed. The role of calcination temperature and pulverization on the photocatalytic action has also been established. Particles have been synthesized in pure form as well as using surfactants such as cetrimide (cetyl trimethyl ammonium bromide), polyethylene glycol (PEG) and SDS (sodium dodecyl sulphate) to enhance their photocatalytic action. This paper also discusses the characterization of these nanoparticles by powder XRD, SEM, FT-IR and UV-Visible spectroscopy. Decolourisation was achieved to completion under optimum experimental conditions at room temperature ascertaining the application of these nanostructures as effective photocatalysts.

  14. Effects of zinc oxide nanoparticles on the performance characteristics of cotton, polyester and their blends

    NASA Astrophysics Data System (ADS)

    Shady, K. E.; Michael, M. N.; Shimaa, H. A.

    2012-07-01

    Nanotechnology is defined as utilization of structure with at least one dimension of nanometer size. These nano structures are capable of enhancing the physical and performance properties of conventional textiles. On this basis, this research work study and compare the effect of nano zinc oxide particles having particle size less than 100nm with different concentrations (0.25%, 0.5%, 1%, and 2%) on the properties of three different fabrics namely cotton, polyester and blend cotton/polyester (65/35).The effectiveness of the treatment was assessed through the following standard tests; X-ray diffraction (XRD), tensile strength and percentage elongation, crease recovery angle, air permeability, whiteness index and ultra violet protection factor (UPF). Generally, the improvement greatly depends on the size and concentration of nanoparticles.

  15. Biokinetics of zinc oxide nanoparticles: toxicokinetics, biological fates, and protein interaction

    PubMed Central

    Choi, Soo-Jin; Choy, Jin-Ho

    2014-01-01

    Biokinetic studies of zinc oxide (ZnO) nanoparticles involve systematic and quantitative analyses of absorption, distribution, metabolism, and excretion in plasma and tissues of whole animals after exposure. A full understanding of the biokinetics provides basic information about nanoparticle entry into systemic circulation, target organs of accumulation and toxicity, and elimination time, which is important for predicting the long-term toxic potential of nanoparticles. Biokinetic behaviors can be dependent on physicochemical properties, dissolution property in biological fluids, and nanoparticle–protein interaction. Moreover, the determination of biological fates of ZnO nanoparticles in the systemic circulation and tissues is critical in interpreting biokinetic behaviors and predicting toxicity potential as well as mechanism. This review focuses on physicochemical factors affecting the biokinetics of ZnO nanoparticles, in concert with understanding bioavailable fates and their interaction with proteins. PMID:25565844

  16. Toxicity mechanism of titanium dioxide and zinc oxide nanoparticles against food pathogens.

    PubMed

    Venkatasubbu, G Devanand; Baskar, R; Anusuya, T; Seshan, C Arun; Chelliah, Ramachandran

    2016-12-01

    Food preservation is an important field of research. It extends the shelf life of major food products. Our current study is based on food preservation through TiO2 and ZnO nanoparticles. TiO2 and ZnO are biocompatible nanomaterial. The biocompatibility of the materials were established through toxicity studies on cell lines. Titanium dioxide and Zinc Oxide nanoparticle were synthesized by wet chemical process. They are characterized by X-Ray diffraction and TEM. The antibacterial activities of both the materials were analysed to ensure their effectiveness as food preservative against Salmonella typhi, Klebsiella pneumoniae and Shigella flexneri. The results indicates that TiO2 and ZnO nanoparticle inhibits Salmonella, Klebsiella and Shigella. The mode of action is by the generation of ROS in cases of Salmonella, Klebsiella. Mode of action in Shigella is still unclear. It was also proved that TiO2 and ZnO nanoparticle are biocompatible materials.

  17. Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors Fabricated by Direct Transfer Printing

    NASA Astrophysics Data System (ADS)

    Adachi, Susumu; Okamura, Shoichi

    2010-10-01

    This letter describes the fabrication of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) by direct transfer printing. An a-IGZO layer and a silicon dioxide (SiO2) layer were sequentially sputtered on a poly(dimethylsiloxane) (PDMS) stamp; the stamp was then pressed onto a glass substrate on which a gate metal had been previously deposited. Then, a-IGZO/SiO2 layers were successfully transferred by simply releasing the stamp from the substrate; a bottom-gate TFT was finally constructed. The measured current-voltage characteristics exhibited good field-effect mobility exceeding 10 cm2 V-1 s-1. The on/off current ratio and subthreshold slope were 4×105 and 0.86 V/decade, respectively.

  18. Impact of temperature on zinc oxide particle size by using sol-gel process

    SciTech Connect

    Lee, Keanchuan Ching, Dennis Ling Chuan; Saipolbahri, Zulhilmi Akmal bin; Guan, Beh Hoe E-mail: hassan.soleimani@petronas.com.my; Soleimani, Hassan E-mail: hassan.soleimani@petronas.com.my

    2014-10-24

    Zinc oxide (ZnO) nanoparticles were prepared and synthesized via sol-gel method, by using citric acid as a precursor. The impact of annealing on the particle size was investigated. Based on the results from the Thermogravimetric Analysis (TGA), three different annealing temperature which is 500, 600 and 700 °C were chosen followed by the characterization of the ZnO nanoparticle by using Powder X-Ray Diffraction (PXRD), Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscopy (FESEM). Results showed that the crystallite size estimated from PXRD increased with the annealing temperature which was hexagonal structure for ZnO. TEM further revealed the same tendency which the Zn NPs size also increased with the annealing temperature.

  19. Zinc Oxide Nanorods Shielded with an Ultrathin Nickel Layer: Tailoring of Physical Properties

    PubMed Central

    Mudusu, Devika; Nandanapalli, Koteeswara Reddy; Dugasani, Sreekantha Reddy; Park, Sung Ha; Tu, Charles W.

    2016-01-01

    We report on the development of Ni-shielded ZnO nanorod (NR) structures and the impact of the Ni layer on the ZnO NR properties. We developed nickel-capped zinc oxide nanorod (ZnO/Ni NR) structures by e-beam evaporation of Ni and the subsequent annealing of the ZnO/Ni core/shell nanostructures. The core/shell NRs annealed at 400 °C showed superior crystalline and emission properties. More interestingly, with the increase of annealing temperature, the crystallinity of the Ni shells over the ZnO NRs gradually changed from polycrystalline to single crystalline. The presence of the Ni layer as a polycrystalline shell completely hindered the light emission and transmission of the ZnO NR cores. Further, the band gap of ZnO NRs continuously decreased with the increase of annealing temperature. PMID:27334555

  20. Zinc oxide nanowire arrays for photovoltaic and light-emitting devices

    NASA Astrophysics Data System (ADS)

    Janfeshan, Bita; Sadeghimakki, Bahareh; Jahed, Navid M. S.; Sivoththaman, Siva

    2013-03-01

    Knowledge of carrier transfer, in quantum dot sensitized solar cells, is the key to engineering the device structure and architecture optimization. In this work, Zinc oxide (ZnO) nanowire (NW) arrays were synthesized on glass wafers and on GaN thin films for application in photovoltaic and light-emitting devices. The nanowires grown on glass wafers were incorporated with CdSe/ZnS quantum dots (QD) and their steady state and lifetime photoluminescence (PL) were studied to investigate the feasibility of electron transfer from excited QDs to ZnO NWs. The results provide an indication that the injected electrons, from excited high quantum efficiency QDs, live longer and hence facilitate electron transport without undergoing non-radiative recombination at surface trap states. Morphology and optical properties of the ZnO nanowires on GaN film were also studied for application in light-emitting devices.