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Sample records for zno nanorods prepared

  1. UV and humidity sensing properties of ZnO nanorods prepared by the arc discharge method

    International Nuclear Information System (INIS)

    Fang, F; Futter, J; Markwitz, A; Kennedy, J

    2009-01-01

    The UV and humidity sensing properties of ZnO nanorods prepared by arc discharge have been studied. Scanning electron microscopy and photoluminescence spectroscopy were carried out to analyze the morphology and optical properties of the as-synthesized ZnO nanorods. Proton induced x-ray emission was used to probe the impurities in the ZnO nanorods. A large quantity of high purity ZnO nanorod structures were obtained with lengths of 0.5-1 μm. The diameters of the as-synthesized ZnO nanorods were found to be between 40 and 400 nm. The nanorods interlace with each other, forming 3D networks which make them suitable for sensing application. The addition of a polymeric film-forming agent (BASF LUVISKOL VA 64) improved the conductivity, as it facilitates the construction of conducting networks. Ultrasonication helped to separate the ZnO nanorods and disperse them evenly through the polymeric agent. Improved photoconductivity was measured for a ZnO nanorod sensor annealed in air at 200 deg. C for 30 min. The ZnO nanorod sensors showed a UV-sensitive photoconduction, where the photocurrent increased by nearly four orders of magnitude from 2.7 x 10 -10 to 1.0 x 10 -6 A at 18 V under 340 nm UV illumination. High humidity sensitivity and good stability were also measured. The resistance of the ZnO nanorod sensor decreased almost linearly with increasing relative humidity (RH). The resistance of the ZnO nanorods changed by approximately five orders of magnitude from 4.35 x 10 11 Ω in dry air (7% RH) to about 4.95 x 10 6 Ω in 95% RH air. It is experimentally demonstrated that ZnO nanorods obtained by the arc discharge method show excellent performance and promise for applications in both UV and humidity sensors.

  2. Structural and Optical Properties of Eu Doped ZnO Nanorods prepared by Pulsed Laser Deposition

    KAUST Repository

    Alarawi, Abeer

    2014-06-23

    Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano-rods prepared, for the first time to our knowledge, by pulsed laser deposition (PLD) without any catalyst. X-ray diffraction (XRD) patterns shows that these Eu doped ZnO nanorods are grown along the c-axis of ZnO wurtzite structure. We have studied the effect of the PLD growth conditions on forming vertically aligned Eu doped ZnO nanorods. The structural properties of the material are investigated using a -scanning electron microscope (SEM). The PLD parameters must be carefully controlled in order to obtain c-axis oriented ZnO nanorods on sapphire substrates, without the use of any catalyst. The experiments conducted in order to identify the optimal growth conditions confirmed that, by adjusting the target-substrate distance, substrate temperature, laser energy and deposition duration, the nanorod size could be successfully controlled. Most importantly, the results indicated that the photoluminescence (PL) properties reflect the quality of the ZnO nanorods. These parameters can change the material’s structure from one-dimensional to two-dimensional however the laser energy and frequency affect the size and the height of the nanorods; the xygen pressure changes the density of the nanorods.

  3. Preparation and Photoluminescence of ZnO Comb-Like Structure and Nanorod Arrays

    Science.gov (United States)

    Yin, Song; Chen, Yi-qing; Su, Yong; Zhou, Qing-tao

    2007-06-01

    A large quantity of Zinc oxide (ZnO) comb-like structure and high-density well-aligned ZnO nanorod arrays were prepared on silicon substrate via thermal evaporation process without any catalyst. The morphology, growth mechanism, and optical properties of the both structures were investigated using XRD, SEM, TEM and PL. The resulting comb-teeth, with a diameter about 20 nm, growing along the [0001] direction have a well-defined epitaxial relationship with the comb ribbon. The ZnO nanorod arrays have a diameter about 200 nm and length up to several micrometers growing approximately vertical to the Si substrate. A ZnO film was obtained before the nanorods growth. A growth model is proposed for interpreting the growth mechanism of comb-like zigzag-notch nanostructure. Room temperature photoluminescence measurements under excitation wavelength of 325 nm showed that the ZnO comb-like nanostructure has a weak UV emission at around 384 nm and a strong green emission around 491 nm, which correspond to a near band-edge transition and the singly ionized oxygen vacancy, respectively. In contrast, a strong and sharp UV peak and a weak green peak was obtained from the ZnO nanorod arrays.

  4. Photoelectrochemical properties of the TiO2-ZnO nanorod hierarchical structure prepared by hydrothermal process

    Directory of Open Access Journals (Sweden)

    Bao SUN

    2018-02-01

    Full Text Available In order to increase the transport channels of the photogenerated electrons and enhance the photosensitizer loading ability of the electrode, a new TiO2-ZnO nanorod hierarchical structure is prepared through two-step hydrothermal process. First, TiO2 nanorod array is grown on the FTO conductive glass substrate by hydrothermal proess. Then, ZnO sol is coated onto the TiO2 nanorods through dip-coating method and inverted to ZnO seed layer by sintering. Finally, the secondary ZnO nanorods are grown onto the TiO2 nanorods by the sencond hydrothermal method to form the designed TiO2-ZnO nanorod hierarchical structure. A spin-coating assisted successive ionic layer reaction method (SC-SILR is used to deposit the CdS nanocrystals into the TiO2 nanorod array and the TiO2-ZnO nanorod hierarchical structure is used to form the CdS/TiO2 and CdS/TiO2-ZnO nanocomposite films. Different methods, such as SEM, TEM, XRD, UV-Vis and transient photocurrent, are employed to characterize and measure the morphologies, structures, light absorption and photoelectric conversion performance of all the samples, respectively. The results indicate that, compared with the pure TiO2 nanorod array, the TiO2-ZnO nanorod hierarchical structure can load more CdS photosensitizer. The light absorption properties and transient photocurrent performance of the CdS/TiO2-ZnO nanorod hierarchical structure composite film are evidently superior to that of the CdS/TiO2 nanocomposite films. The excellent photoelctrochemical performance of theTiO2-ZnO hierarchical structure reveales its application prospect in photoanode material of the solar cells.

  5. Effects of ZnO Seed Layers Prepared with Various Precursor Concentrations on Structural and Defect Emission Properties of ZnO Nanorods Grown by Hydrothermal Method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soaram; Nam, Giwoong; Leem, Jae-Young; Kim, Yangsoo [Inje University, Gimhae (Korea, Republic of); Kim, Ghun Sik; Yoon, Sung Pil [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2013-07-15

    ZnO nanorods were grown by a hydrothermal method on ZnO seed layers that had previously been prepared from solutions containing various precursor concentrations. The effects of the ZnO seed layers prepared with various precursor concentrations on the structural and defect emissions of the ZnO nanorods were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy. The surface morphology of the ZnO seed layers changed with an increasing precursor concentration, and the diameters and densities of the ZnO nanorods depended on the morphologies of the ZnO seed layers. The ZnO seed layers prepared with various precursor concentrations affected the residual stress in the nanorods grown on the seed layers, the intensity and full widths at half maximum of the 2-theta angle in the XRD spectra for the nanorods, and the intensity and position of the defect emission peak in deep-level emission (DLE) PL spectra for the ZnO nanorods.

  6. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei, E-mail: ymgong@dlpu.edu.cn; Guo, Jing, E-mail: guojing8161@163.com

    2016-12-01

    Highlights: • Polymeric PET fibers were conductive modified by ITO and the subsequent Ag coating. The conductive PET-ITO-Ag fiber has the surface resistivity as low as 0.23 mΩ cm. The PET-ITO-Ag fiber was used as a basal material to plant vertical ZnO nanorods. - Abstract: We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol–gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl{sub 2}, a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  7. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    International Nuclear Information System (INIS)

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei; Guo, Jing

    2016-01-01

    Highlights: • Polymeric PET fibers were conductive modified by ITO and the subsequent Ag coating. The conductive PET-ITO-Ag fiber has the surface resistivity as low as 0.23 mΩ cm. The PET-ITO-Ag fiber was used as a basal material to plant vertical ZnO nanorods. - Abstract: We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol–gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl 2 , a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  8. Preparation, optical properties of ZnO, ZnO:Al nanorods and Y(OH)3:Eu nanotube

    International Nuclear Information System (INIS)

    Tran Kim Anh; Dinh Xuan Loc; Lam thi Kieu Giang; Le Quoc Minh; Strek, Wieslaw

    2009-01-01

    ZnO, ZnO:Al nanorods and Y(OH) 3 nanotubes have been prepared by the chemical vapor deposition and liquid phase synthesis. ZnO nanorods with diameter of 50 - 100 nm and length of 5 μm have been obtained by the CVD method. ZnO:Al nanorods were synthesized by the hydrothermal method from ZnSO 4. and Al 2 (SO 4 ) 3 . Nanorods and nanotubes of Y(OH) 3 with diameter of 200 nm and length of several micrometers were prepared by the soft template method. The crystal structure and morphology of rods and tubes were analyzed by the X-Ray diffraction and FE-SEM. The influence of fabrication conditions and Al, Eu concentration have been discussed.

  9. Preparation, optical properties of ZnO, ZnO:Al nanorods and Y(OH){sub 3}:Eu nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Tran Kim Anh; Dinh Xuan Loc; Lam thi Kieu Giang; Le Quoc Minh [Institute of Materials Science, Vietnamese Academy of Science and Technology 18 Hoang Quoc Viet, Nghia Do, Cau Giay, Hanoi (Viet Nam); Strek, Wieslaw [Institute of Low Temperature and Structure Research, PAN, 2 Okolna, Wroclaw (Poland)], E-mail: kimanh1949@gmail.com

    2009-01-01

    ZnO, ZnO:Al nanorods and Y(OH){sub 3} nanotubes have been prepared by the chemical vapor deposition and liquid phase synthesis. ZnO nanorods with diameter of 50 - 100 nm and length of 5 {mu}m have been obtained by the CVD method. ZnO:Al nanorods were synthesized by the hydrothermal method from ZnSO{sub 4.} and Al{sub 2}(SO{sub 4}){sub 3}. Nanorods and nanotubes of Y(OH){sub 3} with diameter of 200 nm and length of several micrometers were prepared by the soft template method. The crystal structure and morphology of rods and tubes were analyzed by the X-Ray diffraction and FE-SEM. The influence of fabrication conditions and Al, Eu concentration have been discussed.

  10. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    Science.gov (United States)

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei; Guo, Jing

    2016-12-01

    We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol-gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl2, a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  11. Morphology-controllable of Sn doped ZnO nanorods prepared by spray pyrolysis for transparent electrode application

    Science.gov (United States)

    Hameed, M. Shahul; Princice, J. Joseph; Babu, N. Ramesh; Zahirullah, S. Syed; Deshmukh, Sampat G.; Arunachalam, A.

    2018-05-01

    Transparent conductive Sn doped ZnO nanorods have been deposited at various doping level by spray pyrolysis technique on glass substrate. The structural, surface morphological and optical properties of these films have been investigated with the help of X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and UV-Vis spectrophotometer respectively. XRD patterns revealed a successful high quality growth of single crystal ZnO nanorods with hexagonal wurtzite structure having (002) preferred orientation. The scanning electron microscope (SEM) image of the prepared films exposed the uniform distribution of Sn doped ZnO nanorod shaped grains. All these films were highly transparent in the visible region with average transmittance of 90%.

  12. Preparation and characterization of electrodeposited ZnO and ZnO:Co nanorod films for heterojunction diode applications

    Energy Technology Data Exchange (ETDEWEB)

    Caglar, Yasemin, E-mail: yasemincaglar@anadolu.edu.tr [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey); Arslan, Andaç [Eskisehir Osmangazi University, Art and Science Faculty, Chemistry Department, Eskisehir (Turkey); Ilican, Saliha [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey); Hür, Evrim [Eskisehir Osmangazi University, Art and Science Faculty, Chemistry Department, Eskisehir (Turkey); Aksoy, Seval; Caglar, Mujdat [Anadolu University, Science Faculty, Physics Department, Eskisehir (Turkey)

    2013-10-15

    Highlights: •Undoped and Co-doped ZnO films were deposited on p-Si by electrodeposition method. •The effects of Co doping on some properties of ZnO films were investigated. •ZnO morphology was converted uniform multi-oriented rods with incorporation of Co. •Co-doped ZnO nanorod films showed a multi-oriented spear-like structure. -- Abstract: Well-aligned undoped and Co-doped nanorod ZnO films were grown by electrochemical deposition onto p-Si substrates from an aqueous route. Aqueous solution of Zn(NO{sub 3}){sub 2}⋅6H{sub 2}O and hexamethylenetetramine (HMT) were prepared using triple distilled water. Two different atomic ratios of Co(NO{sub 3}){sub 2}⋅6H{sub 2}O were used as a dopant element. Electrodepositions were carried out in a conventional three electrode cell for the working electrode (p-Si), reference electrode (Ag/AgCl, sat.) and counter electrode (platin wire). The effects of Co doping on the structural, morphological and electrical properties of ZnO films were investigated. X-ray diffraction (XRD) measurement showed that the undoped ZnO nanorod film was crystallized in the hexagonal wurtzite phase and presented a preferential orientation along the c-axis. Only one peak, corresponding to the (0 0 2) phase, appeared on the diffractograms. The lattice parameters and texture coefficient values were calculated. The nanorods were confirmed by the field emission scanning electron microscopy (FE-SEM) measurements. The FE-SEM image showed that the ZnO nanorods grow uniformly on the substrates, providing a surface with fairly homogeneous roughness. The surface morphology was transformed into uniform multi-oriented rods with incorporation of Co. Co-doped ZnO nanorod films showed a multi-oriented spear-like structure. The diffuse reflectance spectra of the films were measured and the optical band gap values were determined using Kubelka–Munk theory. The van der Pauw method was used to measure the sheet resistance of the films. The sheet resistance

  13. Superhydrophobic and anti-reflective ZnO nanorod-coated FTO transparent conductive thin films prepared by a three-step method

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bao-jia, E-mail: li_bjia@126.com [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang, 212013 (China); Huang, Li-jing; Ren, Nai-fei [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang, 212013 (China); School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Kong, Xia; Cai, Yun-long; Zhang, Jie-lu [Jiangsu Tailong Reduction Box Co. Ltd., Taixing, 225400 (China)

    2016-07-25

    A ZnO nanorod-coated FTO film was prepared by sputtering an AZO layer on FTO glass, thermal annealing of the AZO/FTO film, and hydrothermal growth of ZnO nanorods at 70 °C on the annealed AZO/FTO film using zinc foils as zinc source. Two other ZnO nanorod-coated FTO films were also prepared by hydrothermal growths of ZnO nanorods on the FTO glass and the unannealed AZO/FTO film respectively for comparison purpose. The results were observed in detail using X-ray diffraction, scanning electron microscopy, water contact/sliding angle measurement, spectrophotometry and four-point probe measurement. The ZnO nanorods on the annealed AZO/FTO film were found to exhibit denser distribution and better orientation than those on the FTO glass and the unannealed AZO/FTO film. As a result, the ZnO nanorod-coated annealed AZO/FTO film demonstrated superhydrophobicity, high transparency and low reflectance in the visible range. Also this film had the lowest sheet resistance of 4.0 Ω/sq, implying its good electrical conductivity. This investigation provides a valuable reference for developing multifunctional transparent conductive films. - Highlights: • ZnO nanorod-coated annealed AZO/FTO film was obtained by a three-step method. • FTO and unannealed AZO/FTO films were also used as substrates for comparison. • ZnO nanorods on the annealed AZO/FTO film were denser and more vertically-oriented. • The ZnO nanorod-coated annealed AZO/FTO film (Z/TA-FTO) had superhydrophobicity. • The Z/TA-FTO exhibited high transparency, low reflectance and good conductivity.

  14. Defects in ZnO nanorods prepared by a hydrothermal method.

    Science.gov (United States)

    Tam, K H; Cheung, C K; Leung, Y H; Djurisić, A B; Ling, C C; Beling, C D; Fung, S; Kwok, W M; Chan, W K; Phillips, D L; Ding, L; Ge, W K

    2006-10-26

    ZnO nanorod arrays were fabricated using a hydrothermal method. The nanorods were studied by scanning electron microscopy, photoluminescence (PL), time-resolved PL, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy before and after annealing in different environments and at different temperatures. Annealing atmosphere and temperature had significant effects on the PL spectrum, while in all cases the positron diffusion length and PL decay times were increased. We found that, while the defect emission can be significantly reduced by annealing at 200 degrees C, the rods still have large defect concentrations as confirmed by their low positron diffusion length and short PL decay time constants.

  15. Synthesis of 1-D ZnO nanorods and polypyrrole/1-D ZnO ...

    Indian Academy of Sciences (India)

    1-D ZnO nanorods and PPy/1-D ZnO nanocomposites were prepared by the surfactant-assisted precipitation and in situ polymerization method, respectively. The synthesized nanorods and nanocomposites were characterized by UV–Vis spectrophotometer, Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction ...

  16. ZnO nanorod arrays prepared by chemical bath deposition combined with rapid thermal annealing: structural, photoluminescence and field emission characteristics

    International Nuclear Information System (INIS)

    Chen, Hung-Wei; He, Hsin-Min; Lee, Yi-Mu; Yang, Hsi-Wen

    2016-01-01

    ZnO nanorod arrays were prepared by low temperature chemical bath deposition (CBD) combined with rapid thermal annealing (RTA) under different ambient conditions. The structure and morphology of the synthesized ZnO have been characterized by field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The obtained ZnO samples are highly crystalline with a hexagonal wurtzite phase and also display well-aligned array structure. A pronounced effect on increased nanorod length was found for the RTA-treated ZnO as compared to the as-grown ZnO. Analysis of XRD indicates that the (0 0 2) feature peak of the as-grown ZnO was shifted towards a lower angle as compared to the peaks of RTA-treated ZnO samples due to the reduction of tensile strain along the c-axis by RTA. Photoluminescence (PL) studies reveal that the ZnO nanorod arrays receiving RTA in an O 2 environment have the sharpest UV emission band and greatest intensity ratio of near band-edge emission (NBE) to deep level emission (DLE). Additionally, the effects of RTA on the field emission properties were evaluated. The results demonstrate that RTA an O 2 environment can lower the turn-on field and improve the field enhancement factor. The stability of the field emission current was also tested for 4 h. (paper)

  17. Fabrication and photovoltaic properties of ZnO nanorods/perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shirahata, Yasuhiro; Tanaike, Kohei; Akiyama, Tsuyoshi; Fujimoto, Kazuya; Suzuki, Atsushi; Balachandran, Jeyadevan; Oku, Takeo, E-mail: oku@mat.usp.ac.jp [Department of Materials Science, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533 (Japan)

    2016-02-01

    ZnO nanorods/perovskite solar cells with different lengths of ZnO nanorods were fabricated. The ZnO nanorods were prepared by chemical bath deposition and directly confirmed to be hexagon-shaped nanorods. The lengths of the ZnO nanorads were controlled by deposition condition of ZnO seed layer. Photovoltaic properties of the ZnO nanorods/CH{sub 3}NH{sub 3}PbI{sub 3} solar cells were investigated by measuring current density-voltage characteristics and incident photon to current conversion efficiency. The highest conversion efficiency was obtained in ZnO nanorods/CH{sub 3}NH{sub 3}PbI{sub 3} with the longest ZnO nanorods.

  18. Effect of precursor concentration on the structural and optical properties of ZnO nanorods prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Lestari, Amie; Iwan, S.; Djuhana, Dede; Imawan, Cuk; Harmoko, Adhi; Fauzia, Vivi

    2016-01-01

    Zinc oxide (ZnO) nanorods has attractive properties for nanoscale optoelectronic applications, such as optical sensors, ultraviolet laser diodes, and photodetectors. ZnO nanorods, can be fabricated by simple and low cost chemical approach, such as hydrothermal method. In this method, the morphology, microstructure, optical and electrical properties of ZnO nanorods are highly determined by process parameters such as solvent, deposition time, deposition temperature as well as annealing condition. In this paper we report the fabrication of ZnO nanorods that were grown on transparent conducting indium tin oxide coated glass substrates. Initially, ZnO seed layers were deposited on heated substrates with temperature of 450 °C using ultrasonic spray pyrolysis method with frequency of 1.7 MHz and then grown by hydrothermal method with three different precursor concentrations, namely 0.02 M, 0.06 M, and 0.1 M. The surface morphology and structure were investigated by field emission scanning electron microscope (FESEM) and x-ray diffraction (XRD), while the optical properties were observed by photoluminescence (PL) and and UV VIS reflectance spectroscopy.

  19. Aqueous chemical growth and application of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Postels, Bianca; Kasprzak, Anna; Mofor, Augustine C.; Wehmann, Hergo-Heinrich; Bakin, Andrey; Waag, Andreas [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Str. 66, 38106 Braunschweig (Germany)

    2007-07-01

    A very promising fabrication process for ZnO nanostructures is the aqueous chemical growth (ACG), since it is a cost efficient and low temperature approach. Using this growth technique we generated wafer-scale ZnO nanorod arrays on Si, sapphire, ITO coated glass and even on flexible polymer substrates. ACG is found to be only weakly influenced by the substrate material and we are also able to control the dimensions of the ZnO nanorods. Another benefit of ACG is the ability to fabricate patterned arrays of ZnO nanorods by a selective growth process on structured metallised surfaces. Results of structural analysis with SEM and XRD are reported. Additionally, optical properties were investigated by PL measurements. First attempts on the preparation of dye sensitised solar cells (DSSCs) are also reported. Here, the traditional sintered TiO{sub 2} nanoparticles are replaced by a densely packed and vertically aligned array of ACG ZnO nanorods. The size and morphology of the ZnO nanorods can be controlled. The influence of the length of the nanorods on the cell properties is investigated. A vapour phase transport technique was also used as alternative growth method.

  20. Annealing effect on the photoluminescence properties of ZnO nanorod array prepared by a PLD-assistant wet chemical method

    International Nuclear Information System (INIS)

    Wei Sufeng; Lian Jianshe; Wu Hua

    2010-01-01

    Well-aligned ZnO nanorod arrays were synthesized by a wet chemical method on the glass substrate with ZnO thin film as seed layer prepared by pulsed laser deposition. The effect of annealing temperature on the luminescence characteristics was investigated. As the annealing temperature increased, the photoluminescence properties show a general enhancing tendency. The nanorod array with high ultraviolet emission and negligible visible light emission (designated by the photoluminescence intensity ratio of ultraviolet to visible emission of 66.4) is obtained by annealing the sample at 700 deg. C for 1 h. Based on the results of X-ray photoelectron spectroscopy and photoluminescence spectra, the mechanisms of visible emission were discussed. - Research Highlights: → ZnO nanorod array with good crystallography, low defects concentration and good optical property was obtained after annealed at 700 deg. C for 1 h. → The transition from the conduction band to the O i level may be responsible for the yellow-green emission. → The yellow emission may originate from the presence of Zn(OH) 2 on the surface or the band transition from conduction band to V o Zn i level. → The transition from the Zn i level to the level should produce an orange emission or an orange-red emission.

  1. Structural and Optical Properties of Eu Doped ZnO Nanorods prepared by Pulsed Laser Deposition

    KAUST Repository

    Alarawi, Abeer

    2014-01-01

    Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano

  2. Photoluminescence and lasing properties of ZnO nanorods

    International Nuclear Information System (INIS)

    Lee, Geon Joon; Lee, Young Pak; Min, Sun Ki; Han, Sung Hwan; Lim, Hwan Hong; Cha, Myoung Sik; Kim, Sung Soo; Cheong, Hyeon Sik

    2010-01-01

    In this study, we investigated the structures, photoluminescence (PL), and lasing characteristics of the ZnO nanorods prepared by using chemical bath deposition. The continuous-wave HeCd laser excited PL spectra of the ZnO nanorods exhibited two emission bands, one in the UV region and the other in the visible region. The UV emission band has its peak at 3.25 eV with a bandwidth of 160 meV. However, the PL spectra under 355-nm, 35-ps pulse excitation exhibited a spectrally-narrowed UV emission band with a peak at 3.20 eV and a spectral width of 35 meV. The lasing phenomena were ascribed to the amplified spontaneous emission (ASE) caused by coupling of the microcavity effect of ZnO nanorods and the high-intensity excitation. Above the lasing threshold, the ASE peak intensity exhibited a superlinear dependence on the excitation intensity. For an excitation pulse energy of 3 mJ, the ASE peak intensity was increased by enlarging the length of the ZnO nanorods from 1 μm to 4 μm. In addition, the PL spectrum under 800-nm femtosecond pulse excitation exhibited second harmonic generation, as well as the multiphoton absorption-induced UV emission band. In this research, ZnO nanorods were grown on seed layers by using chemical bath deposition in an aqueous solution of Zn(NO 3 ) 2 and hexamethyltetramine. The seed layers were prepared on conducting glass substrates by dip coating in an aqueous colloidal dispersion containing 50% 70-nm ZnO nanoparticles. Scanning electron microscopy clearly revealed that ZnO nanorods were successfully grown on the seed layers.

  3. Solvothermal preparation of ZnO nanorods as anode material for improved cycle life Zn/AgO batteries.

    Directory of Open Access Journals (Sweden)

    Shafiq Ullah

    Full Text Available Nano materials with high surface area increase the kinetics and extent of the redox reactions, thus resulting in high power and energy densities. In this study high surface area zinc oxide nanorods have been synthesized by surfactant free ethylene glycol assisted solvothermal method. The nanorods thus prepared have diameters in the submicron range (300 ~ 500 nm with high aspect ratio. They have uniform geometry and well aligned direction. These nanorods are characterized by XRD, SEM, Specific Surface Area Analysis, solubility in alkaline medium, EDX analysis and galvanostatic charge/discharge studies in Zn/AgO batteries. The prepared zinc oxide nanorods have low solubility in alkaline medium with higher structural stability, which imparts the improved cycle life stability to Zn/AgO cells.

  4. Electrical anisotropy properties of ZnO nanorods analyzed by conductive atomic force microscopy

    International Nuclear Information System (INIS)

    Wu Yunfeng; Yu Naisen; Liu Dongping; He Yangyang; Liu Yuanda; Liang Hongwei; Du Guotong

    2013-01-01

    Highlights: ► The electrical properties of one individual lying ZnO nanorod were performed by C-AFM measurement. ► Inhomogeneous spatial current distribution was detected. ► Current was detected along the side facets while no current was detected in the top plane for ZnO nanorod. ► The side facets were more conductive than the top facets of ZnO nanorods. - Abstract: In this study, we have prepared ZnO nanorods on cracked GaN substrates using aqueous solution method. Unique electrical characterization of one individual lying ZnO nanorod is analyzed by conductive atomic force microscopy (C-AFM). Effect of anisotropy properties on the conductivity of a single nanorod has been investigated. The current maps of ZnO nanorods have been simultaneously recorded with the topography which is gained by AFM-contact mode. The C-AFM measurement present local current–voltage (I–V) characteristics of the side facets of one individual lying nanorod, however, no current is detected on the top facets of ZnO nanorods. Measurement results indicate that the side facets are more electrically active than the top facets of ZnO nanorods due to lower Schottky barrier height of the side facets.

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

    Science.gov (United States)

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

    2013-08-19

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

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

    Directory of Open Access Journals (Sweden)

    Zafar Hussain Ibupoto

    2013-08-01

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

  7. Electrical characterization of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Schlenker, E.; Bakin, A.; Postels, B.; Mofor, A.C.; Wehmann, H.H.; Waag, A. [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Weimann, T.; Hinze, P. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany)

    2007-05-15

    Zinc oxide (ZnO) nanorods were grown by a wet chemical approach and by vapor phase transport. To explore the electrical properties of individual nanostructures current-voltage (I-V) characteristics were obtained by using an atomic force microscope (AFM) with a conductive tip or by detaching the nanorods from the growth substrate, transferring them to an isolating substrate and contacting them with evaporated Ti/Au electrodes patterned by electron-beam lithography. The AFM-approach only yields a Schottky diode behavior, while the Ti/Au forms ohmic contacts to the ZnO. For the latter method the obtained I-V curves reveal a resistivity of the nanorods in the order of 10{sup -5} {omega} cm which is unusually low for undoped ZnO. We therefore assume the existence of a highly conductive surface channel. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Stimulated emission from ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Hauschild, R.; Lange, H.; Priller, H.; Klingshirn, C.; Kalt, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe (T.H.), 76128 Karlsruhe (Germany); Kling, R. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Waag, A. [Institut fuer Halbleitertechnik, TU-Braunschweig, H.-Sommer-Str. 66, 38106 Braunschweig (Germany); Fan, H.J.; Zacharias, M. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2006-03-15

    By means of time resolved spectroscopy we compare two samples of ZnO nanorods with respect to their suitability as stimulated emitters. In the case of narrow nanorods their wave guiding quality causes a suppression of exciton-exciton scattering whereas no laser emission is detectable. Unlike their narrow counterparts, wide nanorods not only benefit from a larger overlap of the guided mode with the gain medium but a variation in VLS growth results in gold nanoparticles being present at the bottom of nanorods. Consequently, laser emission from single wide rods is evidenced up to 150 K. In addition to experimental studies we carry out 3D numerical simulations of the electric field distribution to evaluate the influence of gold nanoparticles at the nanorod/substrate interface. This finite element analysis confirms that gold leads to an enhancement of confinement within the resonator. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Preparation of Aligned ZnO Nanorod Arrays on Sn-Doped ZnO Thin Films by Sonicated Sol-Gel Immersion Fabricated for Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    I. Saurdi

    2014-01-01

    Full Text Available Aligned ZnO Nanorod arrays are deposited on the Sn-doped ZnO thin film via sonicated sol-gel immersion method. The structural, optical, and electrical properties of the Sn-doped ZnO thin films were investigated. Results show that the Sn-doped ZnO thin films with small grain size (~20 nm, high average transmittance (96% in visible region, and good resistivity 7.7 × 102 Ω·cm are obtained for 2 at.% Sn doping concentration. The aligned ZnO nanorod arrays with large surface area were also obtained for 2 at.% Sn-doped ZnO thin film. They were grown on sol-gel derived Sn-doped ZnO thin film, which acts as a seed layer, via sonicated sol-gel immersion method. The grown aligned ZnO nanorod arrays show high transmittance at visible region. The fabricated dye-sensitised solar cell based on the 2.0 at.% Sn-doped ZnO thin film with aligned ZnO nanorod arrays exhibits improved current density, open-circuit voltage, fill factor, and conversion efficiency compared with the undoped ZnO and 1 at.% Sn-doped ZnO thin films.

  10. A simple method to prepare ZnO and Al(OH)3 nanorods by the reaction of the metals with liquid water

    International Nuclear Information System (INIS)

    Panchakarla, L.S.; Shah, M.A.; Govindaraj, A.; Rao, C.N.R.

    2007-01-01

    Reaction of liquid water with Zn and Al powders and foils have been investigated in the 25-75 deg. C range. The reaction of Zn metal powder with water in this temperature range yields ZnO nanorods. The diameter of the nanorods decreases slightly with the increase in the reaction temperature, accompanied by an increase in the relative intensity of UV emission band. Zn metal foils also yield ZnO nanorods on reaction with water in the 25-75 deg. C range. Reaction of Al metal powder or foil with water in the 25-75 deg. C range yields Al(OH) 3 nanorods. The formation of ZnO and Al(OH) 3 nanorods by the reaction of the metals with water is suggested to occur because of the decomposition of water by the metal giving hydrogen. - Graphical abstract: The reaction of water at a temperature in the 25-27 deg. C range with zinc metal gives rise to ZnO nanorods; with Al metal water gives Al(OH) 3 nanorods

  11. Constructing MnO{sub 2}/single crystalline ZnO nanorod hybrids with enhanced photocatalytic and antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Weiwei [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Liu, Tiangui, E-mail: tianguiliu@gmail.com [College of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Cao, Shiyi; Wang, Chen [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Chen, Chuansheng, E-mail: 1666423158@qq.com [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China)

    2016-07-15

    In order to improve the photocatalytic and antibacterial activity of ZnO nanorods, ZnO nanorods decorated with MnO{sub 2} nanoparticles (MnO{sub 2}/ZnO nanorod hybrids) were prepared by using microwave assisted coprecipitation method under the influence of hydrogen peroxide, and the structure, photocatalytic activity and antibacterial property of the products were studied. Experimental results indicated that MnO{sub 2} nanoparticles are decorated on the surface of single crystalline ZnO nanorods. Moreover, the resultant MnO{sub 2}/ZnO nanorod hybrids have been proven to possess good photocatalytic and antibacterial activity, which their degradated efficiency for Rhodamin B (RhB) is twice as the pure ZnO nanorods. Enhancement for photocatalytic and antibacterial activity is mainly attributed to the low band gap energy and excellent electrochemical properties of MnO{sub 2} nanoparticles. - Graphical abstract: The MnO{sub 2}/single crystalline ZnO nanorods hybrids, which MnO{sub 2} nanoparticles are loaded on the surface of ZnO nanorods, were prepared by the step-by-step precipitation method under the assistance of ammonia and hydrogen peroxide. Display Omitted - Highlights: • MnO{sub 2}/ZnO nanorod hybrids were prepared by the step-by-step assembly method. • Single crystalline ZnO nanorods can be decorated by MnO{sub 2} nanoparticles. • MnO{sub 2}/ZnO nanorod hybrids possess good photocatalytic and antibacterial activity. • MnO{sub 2} can improve the photocatalytic activity of ZnO nanorods under visible light.

  12. Growth and investigation of antifungal properties of ZnO nanorod arrays on the glass

    International Nuclear Information System (INIS)

    Eskandari, M.; Haghighi, N.; Ahmadi, V.; Haghighi, F.; Mohammadi, SH.R.

    2011-01-01

    In this study, we have investigated the antifungal activity of ZnO nanorods prepared by the chemical solution method against Candida albicans. In the study, Zinc oxide nanorods have been deposited on glass substrates using the chemical solution method. The as-grown samples are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). X-ray diffraction (XRD) showed zinc oxide nanorods grown in (0 0 2) orientation. The antifungal results indicated that ZnO nanorod arrays exhibit stable properties after two months and play an important role in the growth inhibitory of Candida albicans.

  13. Cu-implanted ZnO nanorods array film: An aqueous synthetic approach

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ajaya Kumar, E-mail: ajayaksingh_au@yahoo.co.in [Department of Chemistry, Govt. VYT PG. Autonomous College Durg, Chhattisgarh (India); Thool, Gautam Sheel [Department of Chemistry, Govt. VYT PG. Autonomous College Durg, Chhattisgarh (India); Singh, R.S. [Department of Physics, Govt. D.T. College, Utai, Durg, Chhattisgarh (India); Singh, Surya Prakash, E-mail: spsingh@iict.res.in [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal road, Tarnaka, Hyderabad 500007 (India)

    2015-01-05

    Highlights: • Cu doped ZnO nanorods were synthesized using low temperature aqueous solution method. • We demonstrated the capping action of TEA via theoretical simulation. • Raman analysis revealed the presence of tensile strain in Cu doped ZnO nanorods. • Growth rate was found to be high in Cu doped ZnO nanorods. - Abstract: Pure and Cu doped ZnO nanorods array are synthesized via two step chemical bath deposition method. The seed layer is prepared by successive ionic layer adsorption reaction (SILAR) method. The synthesized materials have been systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDAX), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) spectroscopy. SEM pictures show the existence of vertically well aligned hexagonal ZnO nanorods. EDAX spectrum confirms the presence of Cu in ZnO nanorods. High intense peak of (0 0 2) plane and E{sub 2}{sup high} mode for XRD and Raman spectrum respectively, suggest the ZnO nanorods are adopted c-axis orientation perpendicular to substrate. XRD and Raman analysis shows the presence of tensile strain in Cu doped ZnO nanorods. Effect of Cu doping on lattice constants, unit cell volume and Zn–O bond length of ZnO nanorods have also been studied. Room temperature PL measurement exhibits two luminescence bands in the spectra i.e. UV emission centered at 3.215 eV and a broad visible band. Theoretical investigation for capping action of triethanolamine is done by Hartree–Fock (HF) method with 3-21G basis set using Gaussian 09 program package.

  14. Synthesis of ZnO nanorods and observation of resistive switching memory in ZnO based polymer nanocomposites

    Science.gov (United States)

    Nair, Manjula G.; Malakar, Meenakshi; Mohapatra, Saumya R.; Chowdhury, Avijit

    2018-05-01

    This research reports the observation of bipolar resistive switching memory in ZnO nanorod based polymer nanocomposites. We synthesized ZnO nanorods by wet-chemical method and characterized them using XRD, UV-VIS spectroscopy and SEM. The synthesized materials have hexagonal ZnO phase with grain size of 24 nm and having strong orientation along (101) direction as observed from XRD. The SEM micrograph confirms the formation of ZnO nanorods with diameter in the range of 10 to 20 nm and length of the order of 1 µm. From optical absorption spectra the band gap is estimated to be 2.42 eV. ZnO nanorods were dispersed in PVDF-HFP polymer matrix to prepare the nanocomposite. This nanocomposite was used as active layer in the devices having sandwich structure of ITO/PVDF-HFP+ZnO nanorods/Al. Bipolar non-volatile memory was observed with ON-OFF resistance ratio of the order of 103 and with a wide voltage window of 2.3V. The switching mechanism could be due to the trapping and de-trapping of electrons by the ZnO nanorods in the nanocomposite during ON and OFF states respectively.

  15. Effect of phosphorus incorporation on morphology and optical properties of ZnO nanorods

    International Nuclear Information System (INIS)

    Fan, Donghua; Zhang, Rong; Wang, Xianghu

    2011-01-01

    Graphical abstract: XPS spectra of the P-doped ZnO nanorods: (a) Zn 2p, (b) O 1s, and (c) P 2p spectra. The red curve in c is the Gauss-fitting curve. (d) Raman spectra of P-doped (curve 1) and pure (curve 2) ZnO nanorods. Research highlights: → P-doped ZnO nanorods have been prepared on Si substrates without any catalyst. → The introduction of phosphorus leads to the growth of tapered tip in the nanorods. → The formation of tapered tip is attributed to the relaxation of the lattice strain along the radial direction. → The strong ultraviolet peak is connected with the phosphorus acceptor-related emissions. -- Abstract: Phosphorus-doped ZnO nanorods have been prepared on Si substrates by thermal evaporation process without any catalyst. X-ray photoelectron spectroscopy and Raman spectra indicate that phosphorus entering into ZnO nanorods mainly occupies Zn site rather than O one. The introduction of phosphorus leads to the morphological changes of nanorods from hexagonal tip to tapered one, which should be attributed to the relaxation of the lattice strain caused by phosphorus occupying Zn site along the radial direction. Transmission electron microscopy shows that phosphorus-doped ZnO nanorods still are single crystal and grow along [0 0 0 1] direction. The effect of phosphorous dopant on optical properties of ZnO nanorods also is studied by the temperature-dependent photoluminescence spectra, which indicates that the strong ultraviolet emission is connected with the phosphorus acceptor-related emissions.

  16. Solvothermal synthesis of nanorods of ZnO, N-doped ZnO and CdO

    International Nuclear Information System (INIS)

    Varghese, Neenu; Panchakarla, L.S.; Hanapi, M.; Govindaraj, A.; Rao, C.N.R.

    2007-01-01

    ZnO nanorods with diameters in the 80-800 nm range are readily synthesized by the reaction of zinc acetate, ethanol and ethylenediamine under solvothermal conditions. The best products are obtained at 330 deg. C with a slow heating rate. Addition of the surfactant Triton -X 100 gave nanorods of uniform (300 nm) diameter. By adding a small amount of liquid NH 3 to the reaction mixture, N-doped ZnO nanorods, with distinct spectroscopic features are obtained. CdO nanorods of 80 nm diameter have been prepared under solvothermal conditions using a mixture of cadmium cupferronate, ethylenediamine and ethanol at 330 deg. C. Similarly, Zn 1-x Cd x O nanorods of a 70 nm diameter are obtained under solvothermal conditions starting with a mixture of zinc acetate, cadmium cupferronate, ethanol and ethylenediamine

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

    Science.gov (United States)

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

    2013-09-30

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

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

    Directory of Open Access Journals (Sweden)

    Anees A. Ansari

    2013-09-01

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

  19. Growth specificity of vertical ZnO nanorods on patterned seeded substrates through integrated chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P. Suresh [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Maniam, S.M. [Centre for Quantum Technologies, National University of Singapore (Singapore); Sundaramurthy, J. [Department of Chemical and Biomolecular Engineering, National University of Singapore (NUS) (Singapore); Arokiaraj, J. [3M R and D Center (Singapore); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); Rajarathnam, D. [CERAR, University of South Australia, Mawson Lakes, SA-5095 (Australia); Srinivasan, M.P. [Department of Chemical and Biomolecular Engineering, National University of Singapore (NUS) (Singapore); Jian, L.K. [Singapore Synchrotron Light Source (SSLS), National University of Singapore (NUS) (Singapore)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Simple integrated chemical process was adopted for specific ZnO nanorod growth. Black-Right-Pointing-Pointer Size and orientation of nanorods are well controlled by optimum reaction time and temperature. Black-Right-Pointing-Pointer Different site-selective ZnO nanorod growths are demonstrated. - Abstract: A simple and cost effective method has been employed for the random growth and oriented ZnO nanorod arrays over as-prepared and patterned seeded glass substrates by low temperature two step growth process and growth specificity by direct laser writing (DLW) process. Scanning electron microscopy (SEM) images and X-ray diffraction analysis confirm the growth of vertical ZnO nanorods with perfect (0 0 2) orientation along c-axis which is in conjunction with optimizing the parameters at different reaction times and temperatures. Transmission electron microscopy (TEM) images show the formation of vertical ZnO nanorods with diameter and length of {approx}120 nm and {approx}400 nm respectively. Photoluminescence (PL) spectroscopic studies show a narrow emission at {approx}385 nm and a broad visible emission from 450 to 600 nm. Further, site-selective ZnO nanorod growth is demonstrated for its high degree of control over size, orientation, uniformity, and periodicity on a positive photoresist ZnO seed layer by simple geometrical (line, circle and ring) patterns of 10 {mu}m and 5 {mu}m dimensions. The demonstrated control over size, orientation and periodicity of ZnO nanorods process opens up an opportunity to develop multifunctional properties which promises their potential applications in sensor, piezoelectric, and optoelectronic devices.

  20. Catalyst growth of single crystal aligned ZnO nanorods on ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dongxu; Andreazza, Caroline; Andreazza, Pascal [Centre de Recherche sur la Matiere Divisee, CNRS-Universite d' Orleans, 1b rue de la Ferollerie, 45071 Orleans cedex 2 (France)

    2005-02-01

    One dimensional ZnO nanorods were successfully fabricated on Si substrates via a simple physical vapor-phase transport method at 950 C. A ZnO shell covered Au/Zn alloy is assumed as the nucleation site, then ZnO nanorods grow following a vapor-solid (VS) process. In order to guide the nanorod growth a c-axis oriented ZnO thin film and Au catalyst were first deposited on Si (100) surface. SEM images show nanorods grown on this substrate are vertical to the substrate surface. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Synthesis and properties of ZnO nanorods as ethanol gas sensors

    International Nuclear Information System (INIS)

    Mirabbaszadeh, K; Mehrabian, M

    2012-01-01

    Uniform ZnO nanorods were synthesized via the sol-gel process under mild conditions in which different ZnO nanostructures have been prepared by changing the pH of growth solution. It was seen that the optimum nanorods were grown at pH 11.33. The prepared ZnO nanostructures and morphologies were characterized by x-ray diffraction and scanning electron microscopy measurements. The ZnO one-dimensional nanostructures were found to have a wurtzite hexagonal crystalline structure and grow along the [001] direction. The optimum nanorods were about 1 μm in length and less than 100 nm in diameter. The ZnO nanostructures have been tested for different concentrations and different operating temperatures for ethanol vapor in air and the surface resistance of the sensors has been evaluated as a function of different parameters. The gas sensor fabricated from ZnO nanorods grown in solution with a special pH exhibited good performance. The sensor response to 5000 ppm ethanol was up to about 2.5 at the operating temperature of 300 °C. The differences in gas-sensing performance between the sensors were analyzed based on the defects created in the nanorods during their fast growth. The correlations between material structures and the properties of the gas sensors are discussed.

  2. Large-scale syntheses of uniform ZnO nanorods and ethanol gas sensors application

    International Nuclear Information System (INIS)

    Chen Jin; Li Jin; Li Jiahui; Xiao Guoqing; Yang Xiaofeng

    2011-01-01

    Research highlights: → The uniform ZnO nanorods could be synthesized by a low temperature, solution-based method. → The results showed that the sample had uniform rod-like morphology with a narrow size distribution and highly crystallinity. → Room-temperature photoluminescence spectra of these nanorods show an exciton emission around 382 nm and a weak deep level emission, indicating the nanorods have high quality. → The sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 400 deg. C. - Abstract: Uniform ZnO nanorods with a gram scale were prepared by a low temperature and solution-based method. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL). The results showed that the sample had uniform rod-like morphology with a narrow size distribution and highly crystallinity. Room-temperature PL spectra of these nanorods show an exciton emission around 382 nm and a negligible deep level emission, indicating the nanorods have high quality. The gas-sensing properties of the materials have been investigated. The results indicate that the as-prepared nanorods show much better sensitivity and stability. The n-type semiconductor gas sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 400 deg. C. ZnO nanorods are excellent potential candidates for highly sensitive gas sensors and ultraviolet laser.

  3. Improving ultraviolet photodetection of ZnO nanorods by Cr doped ZnO encapsulation process

    Science.gov (United States)

    Safa, S.; Mokhtari, S.; Khayatian, A.; Azimirad, R.

    2018-04-01

    Encapsulated ZnO nanorods (NRs) with different Cr concentration (0-4.5 at.%) were prepared in two different steps. First, ZnO NRs were grown by hydrothermal method. Then, they were encapsulated by dip coating method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy, and ultraviolet (UV)-visible spectrophotometer analyses. XRD analysis proved that Cr incorporated into the ZnO structure successfully. Based on optical analysis, band gap changes in the range of 2.74-3.84 eV. Finally, UV responses of all samples were deeply investigated. It revealed 0.5 at.% Cr doped sample had the most photocurrent (0.75 mA) and photoresponsivity (0.8 A/W) of all which were about three times greater than photocurrent and photoresponsivity of the undoped sample.

  4. Enhanced ethanol gas sensing performance of the networked Pd, In2O3-codecorated ZnO nanorod sensor

    Science.gov (United States)

    Lee, Sangmin; Sun, Gun-Joo; Lee, Jae Kyung; Hyun, Soong Keun; Lee, Chongmu

    2017-10-01

    ZnO nanorods codecorated with Pd and In2O3 nanoparticles were synthesized by thermal evaporation of a mixture of ZnO and graphite powders in an oxidizing atmosphere and followed by solvothermal deposition of Pd and In2O3 and their ethanol gas sensing properties were examined. Pristine ZnO nanorods, Pd-decorated ZnO nanorods and In2O3-decorated ZnO nanorods were also prepared in a similar manner. The codecorated ZnO nanorod sensor showed significantly stronger response to ethanol than the other three sensors, suggesting a synergistic effect of Pd and In2O3 codecoration. The former also showed faster response and recovery than the latter. The pristine and codecorated ZnO nanorod sensors exhibited selectivity toward ethanol over other gases such as acetone, CO, benzene, and toluene. The underlying mechanism for the enhanced sensing performance of the Pd, In2O3-codecorated ZnO nanorod sensor toward ethanol is discussed.

  5. Growth of vertically aligned ZnO nanorods using textured ZnO films

    Directory of Open Access Journals (Sweden)

    Meléndrez Manuel

    2011-01-01

    Full Text Available Abstract A hydrothermal method to grow vertical-aligned ZnO nanorod arrays on ZnO films obtained by atomic layer deposition (ALD is presented. The growth of ZnO nanorods is studied as function of the crystallographic orientation of the ZnO films deposited on silicon (100 substrates. Different thicknesses of ZnO films around 40 to 180 nm were obtained and characterized before carrying out the growth process by hydrothermal methods. A textured ZnO layer with preferential direction in the normal c-axes is formed on substrates by the decomposition of diethylzinc to provide nucleation sites for vertical nanorod growth. Crystallographic orientation of the ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis. Composition, morphologies, length, size, and diameter of the nanorods were studied using a scanning electron microscope and energy dispersed x-ray spectroscopy analyses. In this work, it is demonstrated that crystallinity of the ZnO-ALD films plays an important role in the vertical-aligned ZnO nanorod growth. The nanorod arrays synthesized in solution had a diameter, length, density, and orientation desirable for a potential application as photosensitive materials in the manufacture of semiconductor-polymer solar cells. PACS 61.46.Hk, Nanocrystals; 61.46.Km, Structure of nanowires and nanorods; 81.07.Gf, Nanowires; 81.15.Gh, Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.

  6. Polarized Raman scattering of single ZnO nanorod

    International Nuclear Information System (INIS)

    Yu, J. L.; Lai, Y. F.; Wang, Y. Z.; Cheng, S. Y.; Chen, Y. H.

    2014-01-01

    Polarized Raman scattering measurement on single wurtzite c-plane (001) ZnO nanorod grown by hydrothermal method has been performed at room temperature. The polarization dependence of the intensity of the Raman scattering for the phonon modes A 1 (TO), E 1 (TO), and E 2 high in the ZnO nanorod are obtained. The deviations of polarization-dependent Raman spectroscopy from the prediction of Raman selection rules are observed, which can be attributed to the structure defects in the ZnO nanorod as confirmed by the comparison of the transmission electron microscopy, photoluminescence spectra as well as the polarization dependent Raman signal of the annealed and unannealed ZnO nanorod. The Raman tensor elements of A 1 (TO) and E 1 (TO) phonon modes normalized to that of the E 2 high phonon mode are |a/d|=0.32±0.01, |b/d|=0.49±0.02, and |c/d|=0.23±0.01 for the unannealed ZnO nanorod, and |a/d|=0.33±0.01, |b/d|=0.45±0.01, and |c/d|=0.20±0.01 for the annealed ZnO nanorod, which shows strong anisotropy compared to that of bulk ZnO epilayer

  7. Hydrodynamic fabrication of structurally gradient ZnO nanorods.

    Science.gov (United States)

    Kim, Hyung Min; Youn, Jae Ryoun; Song, Young Seok

    2016-02-26

    We studied a new approach where structurally gradient nanostructures were fabricated by means of hydrodynamics. Zinc oxide (ZnO) nanorods were synthesized in a drag-driven rotational flow in a controlled manner. The structural characteristics of nanorods such as orientation and diameter were determined by momentum and mass transfer at the substrate surface. The nucleation of ZnO was induced by shear stress which plays a key role in determining the orientation of ZnO nanorods. The nucleation and growth of such nanostructures were modeled theoretically and analyzed numerically to understand the underlying physics of the fabrication of nanostructures controlled by hydrodynamics. The findings demonstrated that the precise control of momentum and mass transfer enabled the formation of ZnO nanorods with a structural gradient in diameter and orientation.

  8. Optimization of processing parameters on the controlled growth of c-axis oriented ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Malek, M. F., E-mail: mfmalek07@gmail.com; Rusop, M., E-mail: rusop@salam.uitm.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Mamat, M. H., E-mail: hafiz-030@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Musa, M. Z., E-mail: musa948@gmail.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM) Pulau Pinang, Jalan Permatang Pauh, 13500 Permatang Pauh, Pulau Pinang (Malaysia); Saurdi, I., E-mail: saurdy788@gmail.com; Ishak, A., E-mail: ishak@sarawak.uitm.edu.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM) Sarawak, Kampus Kota Samarahan, Jalan Meranek, 94300 Kota Samarahan, Sarawak (Malaysia); Alrokayan, Salman A. H., E-mail: dr.salman@alrokayan.com; Khan, Haseeb A., E-mail: khan-haseeb@yahoo.com [Chair of Targeting and Treatment of Cancer Using Nanoparticles, Deanship of Scientific Research, King Saud University (KSU), Riyadh 11451 (Saudi Arabia)

    2016-07-06

    Optimization of the growth time parameter was conducted to synthesize high-quality c-axis ZnO nanorod arrays. The effects of the parameter on the crystal growth and properties were systematically investigated. Our studies confirmed that the growth time influence the properties of ZnO nanorods where the crystallite size of the structures was increased at higher deposition time. Field emission scanning electron microsope analysis confirmed the morphologies structure of the ZnO nanorods. The ZnO nanostructures prepared under the optimized growth conditions showed an intense XRD peak which reveal a higher c-axis oriented ZnO nanorod arrays thus demonstrating the formation of defect free structure.

  9. Effect of Different Seed Solutions on the Morphology and Electrooptical Properties of ZnO Nanorods

    OpenAIRE

    Kashif, M.; Hashim, U.; Ali, M. E.; Usman Ali, Syed M.; Rusop, M.; Ibupoto, Zafar Hussain; Willander, Magnus

    2012-01-01

    The morphology and electrooptical properties of ZnO nanorods synthesized on monoethanolamine-based seed layer and KOH-based seed layer were compared. The seed solutions were prepared in monoethanolamine in 2-methoxyethanol and potassium hydroxide in methanol, respectively. Zinc acetate dihydrate was as a common precursor in both solutions. The nanorod-ZnOs were synthesized via the spin coating of two different seed solutions on silicon substrates followed by their hydrothermal growth. The sca...

  10. Enormous enhancement of ZnO nanorod photoluminescence

    International Nuclear Information System (INIS)

    Wang, Y.H.; Duan, W.J.; Wu, Z.L.; Zheng, D.; Zhou, X.W.; Zhou, B.Y.; Dai, L.J.; Wang, Y.S.

    2012-01-01

    ZnO nanorod arrays were grown on quartz slices in the aqueous solution of zinc acetate and hexamethylenetetramine at 90 °C. Then ZnO:Mg shells were epitaxially grown on the nanorods to form core/shell structures in the aqueous solution of zinc acetate, magnesium acetate and hexamethylenetetramine at the same temperature. Effects of the shells and UV laser beam irradiation on the crystal structure and photoluminescence properties of ZnO nanorods were studied. ZnO:Mg shells suppress the green emission and enhance the UV emission intensity of the nanorods by 38 times. Enhancement of the UV emission depends on the Mg content in the shells. Short time UV laser beam irradiation could improve ZnO nanorod emission efficiently. The UV emission intensity of ZnO nanorods is enhanced by 71 times by capping and subsequent UV laser beam irradiation. - Highlights: ► ZnO nanorod arrays were grown on quartz slices in solution at 90 °C. ► The nanorods were capped by ZnO:Mg layers to form core/shell structures. ► ZnO:MgO shells suppress the green emission and enhance the UV emission intensity by 38 times. ► The enhancement depends on the Mg content in the shells. ► Exposing the nanorods to 325 laser beam improves the UV emission efficiently. ► Capping and 325 nm laser beam irradiation could enhance the nanorod UV emission intensity by 71 times.

  11. Physical and chemical contributions of a plasma treatment in the growth of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Jang, J.T. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, H., E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, W.J. [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of); Yun, J. [Department of Nano Science and Engineering, Kyungnam University, Changwon, Gyeongnam 631-701 (Korea, Republic of)

    2013-11-15

    Highlights: •ZnO nanorods were grown by hydrothermal synthesis. •Oxygen plasma was done on the surface of seed ZnO nanorods. •The ZnO nanorods with and without plasma treatment were characterized. •The results showed that the optical and structural properties of ZnO nanorods with plasma treatment were enhanced. -- Abstract: We analyzed the enhancement of optical and structural properties of ZnO nanorods by using a plasma treatment. In this study, seed ZnO nanorods were grown by hydrothermal synthesis for 1 h on a ZnO buffered Si substrate. The seed ZnO nanorods were then treated with an oxygen plasma. Next, ZnO was grown for an additional 4 h by hydrothermal synthesis. The resultant ZnO nanorods were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD) and photoluminescence (PL). The measurements showed that the plasma treatment of the seed ZnO nanorods increased the roughness of the buffer layer and the concentration of oxygen ions on the surfaces of the seed ZnO nanorods and the buffer layer, leading to improved optical and structural properties. In this study, we found that the plasma treatment on the seed ZnO nanorods enhanced the optical and structural properties of the ZnO nanorods.

  12. A simple route to scalable fabrication of perfectly ordered ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Liu, D F; Xiang, Y J; Liao, Q; Zhang, J P; Wu, X C; Zhang, Z X; Liu, L F; Ma, W J; Shen, J; Zhou, W Y; Xie, S S

    2007-01-01

    ZnO nanorod arrays with perfect order and uniformity were prepared using a simple, low-cost, commonly available and scalable nanosphere lithography for patterning gold catalyst particles and a successive bottom-up growth technique in a tube furnace chemical vapor deposition system. Each rod in the arrays had perfect surface facets, sharp edges and uniform size. For all of the rods, their sides were oriented the same. This bottom-up assembly method may accelerate the use of ZnO nanorods in real device applications

  13. Effects of Chromium Dopant on Ultraviolet Photoresponsivity of ZnO Nanorods

    Science.gov (United States)

    Mokhtari, S.; Safa, S.; Khayatian, A.; Azimirad, R.

    2017-07-01

    Structural and optical properties of bare ZnO nanorods, ZnO-encapsulated ZnO nanorods, and Cr-doped ZnO-encapsulated ZnO nanorods have been investigated. Encapsulated ZnO nanorods were grown using a simple two-stage method in which ZnO nanorods were first grown on a glass substrate directly from a hydrothermal bath, then encapsulated with a thin layer of Cr-doped ZnO by dip coating. Comparative study of x-ray diffraction patterns showed that Cr was successfully incorporated into the shell layer of ZnO nanorods. Moreover, energy-dispersive x-ray spectroscopy confirmed presence of Cr in this sample. It was observed that the thickness of the shell layer around the core of the ZnO nanorods was at least about 20 nm. Transmission electron microscopy of bare ZnO nanorods revealed single-crystalline structure. Based on optical results, both the encapsulation process and addition of Cr dopant decreased the optical bandgap of the samples. Indeed, the optical bandgap values of Cr-doped ZnO-encapsulated ZnO nanorods, ZnO-encapsulated ZnO nanorods, and bare ZnO nanorods were 2.89 eV, 3.15 eV, and 3.34 eV, respectively. The ultraviolet (UV) parameters demonstrated that incorporation of Cr dopant into the shell layer of ZnO nanorods considerably facilitated formation and transportation of photogenerated carriers, optimizing their performance as a practical UV detector. As a result, the photocurrent of the Cr-doped ZnO-encapsulated ZnO nanorods was the highest (0.6 mA), compared with ZnO-encapsulated ZnO nanorods and bare ZnO nanorods (0.21 mA and 0.06 mA, respectively).

  14. Vapour transport growth of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Mofor, A.C.; Bakin, A.S.; Elshaer, A.; Waag, A. [Technical University Braunschweig, Institute of Semiconductor Technology, Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Technical University Braunschweig, Institute of Applied Physics, Braunschweig (Germany); Bertram, F.; Christen, J. [University of Magdeburg, Department of Solid State Physics, Magdeburg (Germany)

    2007-07-15

    The fabrication of low-dimensional ZnO structures has attracted enormous attention as such nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Many reported fabrication methods, especially for ZnO nanorods are mostly based on catalyst-assisted growth techniques that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on catalyst-free vapour-phase epitaxy growth of ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3} using purely elemental sources at relatively low temperatures and growth pressure. ZnO nanorods with widths of 80-900 nm and lengths of up to 12 {mu}m were obtained. Nanorod density on the order of 10{sup 9} cm{sup -2} with homogenous luminescence and high purity was also noted. (orig.)

  15. Cathodoluminescence of single ZnO nanorod heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Piechal, Bernard; Donatini, Fabrice; Dang, Le Si [CNRS-CEA-UJF joint group ' ' Nanophysique et Semiconducteurs' ' , Universite Joseph Fourier (CNRS UMR 5588), Saint Martin d' Heres (France); Yoo, Jinkyoung; Yi, Gyu-Chul [National CRI Center for Semiconductor Nanorods and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang (Korea); Elshaer, Abdelhamid; Mofor, A.C.; Bakin, Andrey; Waag, Andreas [Institute of Semiconductor Technology (IHT), TU Braunschweig (Germany)

    2007-05-15

    Optical properties of ZnO-based single nanorods are probed by cathodoluminescence (CL) measurements at T = 5 K. We observe a variation of the ZnO near band edge CL by three orders of magnitude along the nanorod axis, accompanied by a spectral blueshift of 10-30 meV. This indicates a rather poor structural quality of the nanorod bottom part, close to the substrate. ZnO/ZnMgO quantum wells grown on top of ZnO nanorods are found to exhibit much stronger confinement effects as compared to their two-dimensional counterparts, suggesting a reduced spontaneous and piezoelectric polarization effects. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Enhanced photovoltaic performance of ZnO nanorod-based dye-sensitized solar cells by using Ga doped ZnO seed layer

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Yuanyao [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Wu, Fang, E-mail: fang01234@163.com [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Mao, Caiying [Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Fang, Liang, E-mail: lfang@cqu.edu.cn [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Guo, Shengchun [Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Zhou, Miao [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China)

    2015-06-05

    Highlights: • ZnO nanorods were grown on Ga-doped ZnO seed layers using hydrothermal method. • Using the ZnO nanorods as photoanodes for fabricated dye-sensitized solar cells. • The highest η of 1.23% can be achieved in a DSSC with 3 at.% Ga-doped in seeds. • The effects of ZnO seed layers on electron transport properties were investigated. • The enhancement performance of DSSCs contributed to higher dye loading and η{sub cc}. - Abstract: Zinc oxide (ZnO) nanorod arrays were grown on FTO substrates with a Ga-doped ZnO (GZO) seed layer by a hydrothermal method. GZO seed layers were obtained via sol–gel technology with Ga concentration in the range of 0–4 at.%. The dye sensitized solar cells (DSSCs) using ZnO nanorod arrays as the photoanode layers were prepared. The effect of Ga dopant concentrations in ZnO seed layer on the morphology features of ZnO nanorod arrays and the performance of DSSCs were systematically investigated. Results indicate that the average diameter and density of ZnO nanorod arrays decrease with increasing Ga concentration, but their length shows an opposite trend. The photocurrent density–voltage (J–V) characteristics reveal that the DSSCs with GZO seed layer exhibit significantly improved photovoltaic performance. In particular, the highest energy conversion efficiency (η) of 1.23% can be achieved in a DSSC with 3 at.% Ga doping, which is increased by 86.36% compared with that of the undoped DSSC. The external quantum efficiency (EQE) spectra and electrochemical impedance spectroscopy (EIS) were employed to explore the photon-to-electron conversion process in DSSCs. It is demonstrated that the performance enhancement of DSSCs based on GZO seed layer can be attributed to higher amount of dye loading, more efficient electron transportation and better electrons collection efficiency.

  17. Polyaniline hybridized surface defective ZnO nanorods with long-term stable photoelectrochemical activity

    International Nuclear Information System (INIS)

    Bera, Susanta; Khan, Hasmat; Biswas, Indranil; Jana, Sunirmal

    2016-01-01

    Highlights: • Polyaniline (PANI) hybridized ZnO nanorods was synthesized by solution method. • Surface defects were found in the nanorods. • The hybrid material exhibited an enhancement in visible light absorption. • A long-term stable photoelectrochemical activity of the material was found. • Advancement in the properties would be PANI hybridization and surface defects. - Abstract: We report surfactant/template free precursor solution based synthesis of polyaniline (PANI) hybridized surface defective ZnO nanorods by a two-step process. Initially, ZnO nanorods have been prepared at 95 °C, followed by hybridization (coating) of PANI onto the ZnO via in situ polymerization of aniline monomer, forming ZnO-PANI nanohybrid (ZP). The structural properties of ZP have been analyzed by X-ray diffraction (XRD) and transmission electron microscopic (TEM) studies. The presence of surface defects especially the oxygen vacancies in ZnO has been characterized by photoluminescence emission, high resolution TEM, X-ray photoelectron spectroscopy (XPS) and micro-Raman spectral measurements. The chemical interaction of PANI with ZnO has been examined by Fourier transform infrared (FTIR) and XPS analyses. A significant enhancement in visible absorption of ZP sample is found as evidenced from UV–vis diffused reflectance spectral study. BET nitrogen adsorption-desorption isotherm shows an improved textural property (pore size, pore volume) of ZP. Moreover, a long-term stable photoelectrochemical activity (PEC) of ZP is found compare to pristine ZnO. The synergic effect of PANI hybridization and the presence of surface defects in ZnO NRs can enhance the PEC by prolonging the recombination rate of photogenerated charge carriers. The effect can also provide large number of active sites to make electrolyte diffusion and mass transportation easier in the nanohybrid. This simple synthesis strategy can be adopted for PANI hybridization with different metal oxide semiconductors

  18. Polyaniline hybridized surface defective ZnO nanorods with long-term stable photoelectrochemical activity

    Energy Technology Data Exchange (ETDEWEB)

    Bera, Susanta; Khan, Hasmat [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India); Biswas, Indranil [Materials Characterization and Instrumentation Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India); Jana, Sunirmal, E-mail: sjana@cgcri.res.in [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India)

    2016-10-15

    Highlights: • Polyaniline (PANI) hybridized ZnO nanorods was synthesized by solution method. • Surface defects were found in the nanorods. • The hybrid material exhibited an enhancement in visible light absorption. • A long-term stable photoelectrochemical activity of the material was found. • Advancement in the properties would be PANI hybridization and surface defects. - Abstract: We report surfactant/template free precursor solution based synthesis of polyaniline (PANI) hybridized surface defective ZnO nanorods by a two-step process. Initially, ZnO nanorods have been prepared at 95 °C, followed by hybridization (coating) of PANI onto the ZnO via in situ polymerization of aniline monomer, forming ZnO-PANI nanohybrid (ZP). The structural properties of ZP have been analyzed by X-ray diffraction (XRD) and transmission electron microscopic (TEM) studies. The presence of surface defects especially the oxygen vacancies in ZnO has been characterized by photoluminescence emission, high resolution TEM, X-ray photoelectron spectroscopy (XPS) and micro-Raman spectral measurements. The chemical interaction of PANI with ZnO has been examined by Fourier transform infrared (FTIR) and XPS analyses. A significant enhancement in visible absorption of ZP sample is found as evidenced from UV–vis diffused reflectance spectral study. BET nitrogen adsorption-desorption isotherm shows an improved textural property (pore size, pore volume) of ZP. Moreover, a long-term stable photoelectrochemical activity (PEC) of ZP is found compare to pristine ZnO. The synergic effect of PANI hybridization and the presence of surface defects in ZnO NRs can enhance the PEC by prolonging the recombination rate of photogenerated charge carriers. The effect can also provide large number of active sites to make electrolyte diffusion and mass transportation easier in the nanohybrid. This simple synthesis strategy can be adopted for PANI hybridization with different metal oxide semiconductors

  19. Photoresponsive surface molecularly imprinted polymer on ZnO nanorods for uric acid detection in physiological fluids

    International Nuclear Information System (INIS)

    Tang, Qian; Li, Zai-yong; Wei, Yu-bo; Yang, Xia; Liu, Lan-tao; Gong, Cheng-bin; Ma, Xue-bing; Lam, Michael Hon-wah; Chow, Cheuk-fai

    2016-01-01

    A photoresponsive surface molecularly imprinted polymer for uric acid in physiological fluids was fabricated through a facile and effective method using bio-safe and biocompatible ZnO nanorods as a support. The strategy was carried out by introducing double bonds on the surface of the ZnO nanorods with 3-methacryloxypropyltrimethoxysilane. The surface molecularly imprinted polymer on ZnO nanorods was then prepared by surface polymerization using uric acid as template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as functional monomer, and triethanolamine trimethacryl ester as cross-linker. The surface molecularly imprinted polymer on ZnO nanorods showed good photoresponsive properties, high recognition ability, and fast binding kinetics toward uric acid, with a dissociation constant of 3.22 × 10"−"5 M in aqueous NaH_2PO_4 buffer at pH = 7.0 and a maximal adsorption capacity of 1.45 μmol g"−"1. Upon alternate irradiation at 365 and 440 nm, the surface molecularly imprinted polymer on ZnO nanorods can quantitatively uptake and release uric acid. - Highlights: • Novel surface molecularly imprinted polymer on ZnO nanorods was synthesized. • ZnO-SMIP showed good selectivity toward uric acid in physiological fluids. • ZnO-SMIP displayed good photoresponsive properties.

  20. Photoresponsive surface molecularly imprinted polymer on ZnO nanorods for uric acid detection in physiological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Qian [The Key Laboratory of Applied Chemistry of Chongqing Municipality, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Department of Science and Environmental Studies, The Hong Kong Institute of Education (Hong Kong); Li, Zai-yong; Wei, Yu-bo; Yang, Xia; Liu, Lan-tao [The Key Laboratory of Applied Chemistry of Chongqing Municipality, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Gong, Cheng-bin, E-mail: gongcbtq@swu.edu.cn [The Key Laboratory of Applied Chemistry of Chongqing Municipality, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Ma, Xue-bing [The Key Laboratory of Applied Chemistry of Chongqing Municipality, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Lam, Michael Hon-wah [Department of Biology and Chemistry, City University of Hong Kong (Hong Kong); Chow, Cheuk-fai, E-mail: cfchow@ied.edu.hk [Department of Science and Environmental Studies, The Hong Kong Institute of Education (Hong Kong)

    2016-09-01

    A photoresponsive surface molecularly imprinted polymer for uric acid in physiological fluids was fabricated through a facile and effective method using bio-safe and biocompatible ZnO nanorods as a support. The strategy was carried out by introducing double bonds on the surface of the ZnO nanorods with 3-methacryloxypropyltrimethoxysilane. The surface molecularly imprinted polymer on ZnO nanorods was then prepared by surface polymerization using uric acid as template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as functional monomer, and triethanolamine trimethacryl ester as cross-linker. The surface molecularly imprinted polymer on ZnO nanorods showed good photoresponsive properties, high recognition ability, and fast binding kinetics toward uric acid, with a dissociation constant of 3.22 × 10{sup −5} M in aqueous NaH{sub 2}PO{sub 4} buffer at pH = 7.0 and a maximal adsorption capacity of 1.45 μmol g{sup −1}. Upon alternate irradiation at 365 and 440 nm, the surface molecularly imprinted polymer on ZnO nanorods can quantitatively uptake and release uric acid. - Highlights: • Novel surface molecularly imprinted polymer on ZnO nanorods was synthesized. • ZnO-SMIP showed good selectivity toward uric acid in physiological fluids. • ZnO-SMIP displayed good photoresponsive properties.

  1. Hydrothermal growth of ZnO nanorods: The role of KCl in controlling rod morphology

    International Nuclear Information System (INIS)

    Downing, Jonathan M.; Ryan, Mary P.; McLachlan, Martyn A.

    2013-01-01

    The role of potassium chloride (KCl) in controlling ZnO nanorod morphology of large area thin films prepared by hydrothermal growth has been extensively investigated. The influence of KCl and growth time on the orientation, morphology and microstructure of the nanorod arrays has been studied with systematic changes in the length, width, density and termination of the nanorods observed. Such changes are attributed to stabilization of the high-energy (002) nanorod surface by the KCl. At low KCl concentrations (< 100 mM) c-axis growth i.e. perpendicular to the polar surface, dominates, leading to nanorods with increased length over the control sample (0 mM KCl). At higher concentrations (> 100 mM) stabilization of the high-energy surface by KCl occurs and planar (002) facets are observed accompanied by increased lateral (100) growth, at the highest KCl concentrations near coalesced (002) terminated rods are observed. Additionally we correlate the KCl concentration with the uniformity of the nanorod arrays; a decrease in polydispersity with increased KCl concentration is observed. The vertical alignment of nanorod arrays was studied using X-ray diffraction, it was found that this parameter increases as growth time and KCl concentration are increased. We propose that the increase in vertical alignment is a result of nanorod–nanorod interactions during the early stages of growth. - Highlights: • Modified hydrothermal growth was used for controlled ZnO nanorod synthesis. • Growth conditions varied to study influence on nanorod morphology and orientation. • A highly controlled and reproducible method is established. • A mechanism for growth and the role of ionic additives is proposed

  2. Synthesis and characterization of ZnO and Ni doped ZnO nanorods by thermal decomposition method for spintronics application

    International Nuclear Information System (INIS)

    Saravanan, R.; Santhi, Kalavathy; Sivakumar, N.; Narayanan, V.; Stephen, A.

    2012-01-01

    Zinc oxide nanorods and diluted magnetic semiconducting Ni doped ZnO nanorods were prepared by thermal decomposition method. This method is simple and cost effective. The decomposition temperature of acetate and formation of oxide were determined by TGA before the actual synthesis process. The X-ray diffraction result indicates the single phase hexagonal structure of zinc oxide. The transmission electron microscopy and scanning electron microscopy images show rod like structure of ZnO and Ni doped ZnO samples with the diameter ∼ 35 nm and the length in few micrometers. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The Ni doped ZnO exhibits room temperature ferromagnetism. This diluted magnetic semiconducting Ni doped ZnO nanorods finds its application in spintronics. - Highlights: ► The method used is very simple and cost effective compared to all other methods for the preparation DMS materials. ► ZnO and Ni doped ZnO nanorods ► Ferromagnetism at room temperature

  3. Effect of Different Seed Solutions on the Morphology and Electrooptical Properties of ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    M. Kashif

    2012-01-01

    Full Text Available The morphology and electrooptical properties of ZnO nanorods synthesized on monoethanolamine-based seed layer and KOH-based seed layer were compared. The seed solutions were prepared in monoethanolamine in 2-methoxyethanol and potassium hydroxide in methanol, respectively. Zinc acetate dihydrate was as a common precursor in both solutions. The nanorod-ZnOs were synthesized via the spin coating of two different seed solutions on silicon substrates followed by their hydrothermal growth. The scanning electron microscopy (SEM, X-ray diffraction (XRD, photoluminescence (PL, and Raman studies revealed that the ZnO nanorods obtained from monoethanolamine-based seed layer had fewer defects, better crystals, and better alignment than those realized via KOH-based seed layer. However, the current-voltage (I-V characteristics demonstrated better conductivity of the ZnO nanorods obtained via KOH-based seed layer. The current measured in forward bias was 4 mA and 40 μA for ZnO-nanorods grown on KOH-based seed layer and monoethanolamine-based with the turn on voltage of approximately 1.5 V and 2.5 V, respectively, showing the feasibility of using both structures in optoelectric devices.

  4. A potentiometric biosensor for the detection of notch 3 using functionalized ZnO nanorods.

    Science.gov (United States)

    Ibupoto, Z H; Khun, K; Liu, X; Willander, M

    2014-09-01

    The notch signalling plays a vital and radical role for the activity of cellular proliferation, differentiation and apoptosis. In this study, for the first time a particular biosensor is developed for the detection of notch 3. ZnO nanorods were fabricated on the gold coated glass substrate by hydrothermal method and afterwards were decorated with the gold nanoparticles by electrodepositing technique. Scanning electron microscopy (SEM) has shown the perpendicular to the substrate growth pattern of ZnO nanorods. X-ray diffraction (XRD) studies showed the c-axis oriented growth direction with wurtzite crystal structure of ZnO nanorods. X-ray Photoelectron Spectroscopy (XPS) and energy dispersive X-ray (EDX) techniques have shown the presence of Zn, O and Au atoms in the prepared functional material. Furthermore, the anti-notch 3 was physically adsorbed on the gold nanoparticles functionalized ZnO nanorods. The developed potentiometric immunosensor has shown response to the wide range of notch 3 molecules. The detected range included 1.00 x 10(-5)-1.50 x 10(0 ) μg/mL with a sensitivity of 23.15 ± 0.31 mV/decade. The analytical parameters including reproducibility, stability, and selectivity were also investigated and the observed results indicate the acceptable performance of the notch 3 biosensor. Moreover, the proposed notch 3 biosensor exhibited a fast response time of 10 s.

  5. Electrical characteristics of ZnO nanorods reinforced polymer nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Snigdha; Roy, Asim, E-mail: 28.asim@gmail.com [Department of Physics National Institute Technology Silchar Silchar-788010, Assam (India)

    2015-05-15

    ZnO nanorods have been prepared by simple chemical method, which is used to fabricate organic bistable devices (OBDs). OBDs are fabricated by incorporating different weight percent (wt %) of chemically synthesized Zinc Oxide (ZnO) nanorods into polymethylmethacrylate (PMMA). Current-voltage (I-V) measurements of the spin coated ZnO+PMMA nanocomopsite thin film on indium tin oxide (ITO) coated glass substrate showed current hysteresis behaviour, which is an indication of memory effect. The samples exhibit two distinct resistance states, ON and OFF states, characterised by relatively low and high resistance of the OBDs, respectively. It is also observed that with change in ZnO dopant concentration the value of ON/OFF current changes. Higher ON/OFF current ratio is desired for practical applications. Current conduction mechanism of the devices has been explained invoking various existing models, and it has been found that the trapped-charge-limited conduction mechanism was dominant in our samples.

  6. Luminescence properties of hydrothermally grown ZnO nanorods

    Czech Academy of Sciences Publication Activity Database

    Yatskiv, Roman; Grym, Jan

    2016-01-01

    Roč. 99, 1November (2016), s. 214-220 ISSN 0749-6036 R&D Projects: GA MŠk(CZ) LD14111; GA ČR GA15-17044S Institutional support: RVO:67985882 Keywords : Photoluminescence * Annealing * ZnO nanorods Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.123, year: 2016

  7. Characteristics of zinc oxide nanorod array/titanium oxide film heterojunction prepared by aqueous solution deposition

    Science.gov (United States)

    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.

  8. Electrodeposition of ZnO nanorods for device application

    Energy Technology Data Exchange (ETDEWEB)

    Postels, B.; Bakin, A.; Wehmann, H.H.; Suleiman, M.; Waag, A. [Technical University of Braunschweig, Institute of Semiconductor Technology, Braunschweig (Germany); Weimann, T.; Hinze, P. [Physikalische Technische Bundesanstalt, Braunschweig (Germany)

    2008-06-15

    We report the electrochemical growth of zinc oxide nanorods in a zinc nitrate/hexamethylenetetramine solution at 70 C. High-density vertical nanorods were grown on Au films on silicon substrates with a texture coefficient better than 99.9%. By varying the reactant concentration the diameter can be varied between 100 and 250 nm, with corresponding lengths of 1 to 4 {mu}m. Furthermore, this approach was used for the selective growth on Ti/Au strip conductors ordered in an interdigitated structure on an insulating substrate. We achieved the growth of ZnO nanorods between neighbouring strip conductors bridging the gap between them. In this configuration the nanorods are already contacted and electrical measurements can be directly performed. First I-V measurements show a good conductivity of the as-grown nanorods and the resistance could be estimated to be 0.1 {omega}cm. Under UV illumination the ZnO nanorods demonstrate a photoconductivity, but only after annealing the sample at 300 C in N{sub 2}. (orig.)

  9. A selective potentiometric copper (II) ion sensor based on the functionalized ZnO nanorods.

    Science.gov (United States)

    Khun, K; Ibupoto, Z H; Liu, X; Nur, O; Willander, M; Danielsson, B

    2014-09-01

    In this work, ZnO nanorods were hydrothermally grown on the gold-coated glass substrate and characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The ZnO nanorods were functionalized by two different approaches and performance of the sensor electrode was monitored. Fourier transform infrared spectroscopy (FTIR) was carried out for the confirmation of interaction between the ionophore molecules and ZnO nanorods. In addition to this, the surface of the electrode was characterized by X-ray photoelectron spectroscopy (XPS) showing the chemical and electronic state of the ionophore and ZnO nanorod components. The ionophore solution was prepared in the stabilizer, poly vinyl chloride (PVC) and additives, and then functionalized on the ZnO nanorods that have shown the Nernstian response with the slope of 31 mV/decade. However, the Cu2+ ion sensor was fabricated only by immobilizing the selective copper ion ionophore membrane without the use of PVC, plasticizers, additives and stabilizers and the sensor electrode showed a linear potentiometric response with a slope of 56.4 mV/decade within a large dynamic concentration range (from 1.0 x 10(-6) to 1.0 x 10(-1) M) of copper (II) nitrate solutions. The sensor showed excellent repeatability and reproducibility with response time of less than 10 s. The negligible response to potentially interfering metal ions such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe3+), zinc (Zn2+), and sodium (Na+) allows this sensor to be used in biological studies. It may also be used as an indicator electrode in the potentiometric titration.

  10. Electrical transport properties of single ZnO nanorods

    International Nuclear Information System (INIS)

    Heo, Y.W.; Tien, L.C.; Norton, D.P.; Kang, B.S.; Ren, F.; Gila, B.P.; Pearton, S.J.

    2004-01-01

    Single ZnO nanorods with diameters of ∼130 nm were grown on Au-coated Al 2 O 3 substrates by catalyst-driven molecular beam epitaxy. Individual nanorods were removed from the substrate and placed between Ohmic contact pads and the current-voltage characteristics measured as a function of temperature and gas ambient. In the temperature range from 25 to 150 deg. C, the resistivity of nanorods treated in H 2 at 400 deg. C prior to measurement showed an activation energy of 0.089±0.02 eV and was insensitive to the ambient used (C 2 H 4 ,N 2 O,O 2 or 10% H 2 in N 2 ). By sharp contrast, the conductivity of nanorods not treated in H 2 was sensitive to trace concentrations of gases in the measurement ambient even at room temperature, demonstrating their potential as gas sensors

  11. Stimulated emission from ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Hauschild, R.; Lange, H.; Priller, H.; Klingshirn, C.; Kalt, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe (TH), 76128 Karlsruhe (Germany); Kling, R. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Waag, A. [Institut fuer Halbleitertechnik, TU-Braunschweig, H.-Sommer-Str. 66, 38106 Braunschweig (Germany); Fan, H.J.; Zacharias, M. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2006-08-15

    We discuss the time-resolved photoluminescence (PL) spectra of single ZnO nanorods taken at excitation fluences above and below the laser threshold. In the latter case, P-band emission related to polariton-polariton scattering is observed for certain rod geometries while stimulated emission occurs within the electron-hole plasma band. We calculate the intensity distribution of low-order waveguide modes as well as their energy dependence for given nanorod geometries to discuss their relevance with respect to nanorod lasing and polariton propagation. Additional finite-element analysis confirms that a gold layer formed at the nanorod-substrate interface under certain growth conditions leads to an enhancement of confinement within the resonator. (2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  12. Superior environment resistance of quartz crystal microbalance with anatase TiO2/ZnO nanorod composite films

    International Nuclear Information System (INIS)

    Qiang, Wei; Wei, Li; Shaodan, Wang; Yu, Bai

    2015-01-01

    Graphical abstract: ZnO nanorod array being prepared by an in situ method on the QCM coated with Au film via hydrothermal process and surface modification with coated TiO 2 by sol–gel methods to form a superhydrophobic TiO 2 /ZnO composite film the anatase TiO 2 /ZnO nanorod composite film with a sharp, pencil-like structure exhibiting excellent superhydrophobicity (water contact angle of 155°), non-sticking water properties, and an autonomous cleaning property under UV irradiation. The anatase TiO 2 /ZnO nanorod composite film facilitates the precise measurement and extended lifetime of the QCM for the detection of organic gas molecules. - Highlights: • This work combines, for the first time, the advantage of the TiO 2 /ZnO composite film on photocatalysis and reversible super-hydrophobic and super-hydrophilic transition, and puts forward a solution to satisfy weatherability of quartz crystal microbalance in long-term application. • The anatase TiO 2 /ZnO nanorod composite film with pencil structure exhibit excellent super-hydrophobicity (water contact angle can reach 155°), no-sticking water properties and self-cleaning property under UV irradiation. • The photocatalysis and reversible super-hydrophobic and super-hydrophilic transition of the TiO 2 /ZnO nanorod composite film is stable in long-term application. - Abstract: The precise measurement of quartz crystal microbalance (QCM) in the detection and weighing of organic gas molecules is achieved due to excellent superhydrophobicity of a deposited film composite. Photocatalysis is utilized as a method for the self-cleaning of organic molecules on the QCM for extended long-term stability in the precision of the instrument. In this paper, ZnO nanorod array is prepared via in situ methods on the QCM coated with Au film via hydrothermal process. Subsequently, a TiO 2 /ZnO composite film is synthesized by surface modification with TiO 2 via sol–gel methods. Results show the anatase TiO 2 /ZnO nanorod

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-28

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

  15. Enhancement in the structure quality of ZnO nanorods by diluted Co dopants: Analyses via optical second harmonic generation

    International Nuclear Information System (INIS)

    Liu, Chung-Wei; Hsiao, Chih-Hung; Chang, Shoou-Jinn; Brahma, Sanjaya; Chang, Feng Ming; Wang, Peng Han; Lo, Kuang-Yao

    2015-01-01

    We report a systematic study about the effect of cobalt concentration in the growth solution over the crystallization, growth, and optical properties of hydrothermally synthesized Zn 1−x Co x O [0 ≤ x ≤ 0.40, x is the weight (wt.) % of Co in the growth solution] nanorods. Dilute Co concentration of 1 wt. % in the growth solution enhances the bulk crystal quality of ZnO nanorods, and high wt. % leads to distortion in the ZnO lattice that depresses the crystallization, growth as well as the surface structure quality of ZnO. Although, Co concentration in the growth solution varies from 1 to 40 wt. %, the real doping concentration is limited to 0.28 at. % that is due to the low growth temperature of 80 °C. The enhancement in the crystal quality of ZnO nanorods at dilute Co concentration in the solution is due to the strain relaxation that is significantly higher for ZnO nanorods prepared without, and with high wt. % of Co in the growth solution. Second harmonic generation is used to investigate the net dipole distribution from these coatings, which provides detailed information about bulk and surface structure quality of ZnO nanorods at the same time. High quality ZnO nanorods are fabricated by a low-temperature (80 °C) hydrothermal synthesis method, and no post synthesis treatment is needed for further crystallization. Therefore, this method is advantageous for the growth of high quality ZnO coatings on plastic substrates that may lead toward its application in flexible electronics

  16. Doping effects of Co2+ ions on ZnO nanorods and their photocatalytic properties

    International Nuclear Information System (INIS)

    Qiu Xiaoqing; Li Guangshe; Sun Xuefei; Li Liping; Fu Xianzhi

    2008-01-01

    A series of Zn 1-x Co x O nanorods with dopant content ranging from x = 0.00 to 0.10 was prepared by a wet chemical method. All Zn 1-x Co x O samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersion x-ray line mapping analysis, and UV-visible absorption spectroscopy. It was found that Co 2+ ions were homogeneously substituted for Zn 2+ ions in ZnO nanorods. Rhodamine B degradation was used as a probe reaction to evaluate the effect of Co 2+ doping on ZnO nanorods and photocatalytic performance under UV light and visible light irradiation. Co 2+ ions acted as the trapping or recombination centers for electrons and holes, leading to a reduction in photodegradation efficiency under UV light illumination. Alternatively, Co 2+ ions enhanced the optical absorption and produced the photoinduced carriers under visible illumination in terms of two charge transfer transitions involving Co 2+ ions. Consequently, Co 2+ ions substituted in the lattice of ZnO nanorods significantly improved the visible light photocatalytic activity

  17. Highly Uniform Epitaxial ZnO Nanorod Arrays for Nanopiezotronics

    Directory of Open Access Journals (Sweden)

    Nagata T

    2009-01-01

    Full Text Available Abstract Highly uniform and c-axis-aligned ZnO nanorod arrays were fabricated in predefined patterns by a low temperature homoepitaxial aqueous chemical method. The nucleation seed patterns were realized in polymer and in metal thin films, resulting in, all-ZnO and bottom-contacted structures, respectively. Both of them show excellent geometrical uniformity: the cross-sectional uniformity according to the scanning electron micrographs across the array is lower than 2%. The diameter of the hexagonal prism-shaped nanorods can be set in the range of 90–170 nm while their typical length achievable is 0.5–2.3 μm. The effect of the surface polarity was also examined, however, no significant difference was found between the arrays grown on Zn-terminated and on O-terminated face of the ZnO single crystal. The transmission electron microscopy observation revealed the single crystalline nature of the nanorods. The current–voltage characteristics taken on an individual nanorod contacted by a Au-coated atomic force microscope tip reflected Schottky-type behavior. The geometrical uniformity, the designable pattern, and the electrical properties make the presented nanorod arrays ideal candidates to be used in ZnO-based DC nanogenerator and in next-generation integrated piezoelectric nano-electromechanical systems (NEMS.

  18. Enhanced photocatalytic activity and synthesis of ZnO nanorods/MoS2 composites

    Science.gov (United States)

    Li, Hui; Shen, Hao; Duan, Libing; Liu, Ruidi; Li, Qiang; Zhang, Qian; Zhao, Xiaoru

    2018-05-01

    A stable and recyclable organic degradation catalyst based on MoS2 functionalized ZnO nanorods was introduced. ZnO nanorods were synthesized on the glass substrates (2 cm*2 cm) by sol-gel method and hydrothermal method and functionalized with MoS2 via an argon flow annealing method. The structure and morphology of the as-prepared samples were characterized by XRD, SEM and TEM. Results showed that a small amount of MoS2 was successfully wrapped on the surfaces of ZnO nanorods. XPS analyses showed the existence of Zn-S between ZnO and MoS2, indicating that the MoS2 was combined with ZnO through chemical bonds and formed the ZnO/MoS2 heterostructure. PL results revealed that ZnO/MoS2 had lower fluorescence spectra indicating an electron transport channel between ZnO and MoS2 which separated electrons and holes. Photocatalytic experiment showed that ZnO/MoS2 composites showed a better photodegradation performance of Rhodamine B (RhB) after functionalized with MoS2 under the UV light irradiation which could be attributed to the separation and transfer of photogenerated electrons and holes between ZnO and MoS2. Meanwhile, the high active adsorption sites on the edges of MoS2 also accelerated the degradation process. Furthermore, the scavengers were used to investigate the major active species and results indicated that h+ was the major reactive species for the degradation.

  19. Properties of V-implanted ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Schlenker, E [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Bakin, A [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Schmid, H [Institut fuer Anorganische Chemie, University of Bonn, Roemerstrasse 164, 53117 Bonn (Germany); Mader, W [Institut fuer Anorganische Chemie, University of Bonn, Roemerstrasse 164, 53117 Bonn (Germany); Sievers, S [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Albrecht, M [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Ronning, C [II. Institute of Physics, Georg-August-University Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Mueller, S [II. Institute of Physics, Georg-August-University Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Al-Suleiman, M [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Postels, B [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Wehmann, H-H [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Siegner, U [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Waag, A [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany)

    2007-03-28

    ZnO nanorods were grown on Si substrates by an aqueous chemical approach and subsequently doped by V implantation. Transmission electron microscopy and photoluminescence spectroscopy reveal a severely defective material directly after the implantation process. Subsequent annealing leads to a partial recovery of the crystal structure. The magnetic features of ZnO:V nanorods were investigated by magnetic force microscopy. Images taken of ensembles as well as of single rods clearly display contrast, which is seen as a strong indication of ferromagnetism at room temperature.

  20. ZnO nanorod array solid phase micro-extraction fiber coating: fabrication and extraction capability

    International Nuclear Information System (INIS)

    Wang Dan; Zhang Zhuomin; Li Tiemei; Zhang Lan; Chen Guonan; Luo Lin

    2009-01-01

    In this paper, a ZnO nanorod array has been introduced as a coating to the headspace solid phase micro-extraction (HSSPME) field. The coating shows good extraction capability for volatile organic compounds (VOCs) by use of BTEX as a standard and can be considered suitable for sampling trace and small molecular VOC targets. In comparison with the randomly oriented ZnO nanorod HSSPME coating, ZnO nanorod array HSSPME fiber coating shows better extraction capability, which is attributed to the nanorod array structure of the coating. Also, this novel nanorod array coating shows good extraction selectivity to 1-propanethiol.

  1. Controllable growth and magnetic properties of nickel nanoclusters electrodeposited on the ZnO nanorod template

    International Nuclear Information System (INIS)

    Tang Yang; Zhao Dongxu; Shen Dezhen; Zhang Jiying; Wang Xiaohua

    2009-01-01

    The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

  2. Controllable growth and magnetic properties of nickel nanoclusters electrodeposited on the ZnO nanorod template

    Energy Technology Data Exchange (ETDEWEB)

    Tang Yang; Zhao Dongxu; Shen Dezhen; Zhang Jiying [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Wang Xiaohua, E-mail: dxzhao2000@yahoo.com.c [National Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 WeiXing Road, ChangChun 130022 (China)

    2009-12-09

    The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

  3. Effect of ALD surface treatment on structural and optical properties of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin-Tak [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, Hyukhyun, E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, Won-Jae [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

    2013-07-01

    In this study, we report on the improvement of the optical and structural properties of ZnO nanorods using atomic layer deposition (ALD) on seed ZnO nanorods. After the initial growth of ZnO seed nanorods by hydrothermal synthesis for 1 h, a ZnO layer with a thickness of 10 nm was deposited on the initial ZnO seed nanorods using ALD. Then ZnO was further grown by hydrothermal synthesis for 4 h. The samples were characterized using room temperature photoluminescence (PL), field emission-scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). From this experiment, it was found that the ZnO nanorods with the ALD surface treatment show improved optical and structural properties when compared with the ZnO nanorods grown only by hydrothermal synthesis. The ZnO nanorods with the ALD surface treatment show about 2.7 times higher XRD (0 0 2) peak intensity, about 2.64 times higher PL NBE peak intensity, and about 3.1 times better NBE/DLE ratio than the ZnO nanorods without an ALD surface treatment.

  4. Diameter Control and Photoluminescence of ZnO Nanorods from Trialkylamines

    Directory of Open Access Journals (Sweden)

    Tamar Andelman

    2007-01-01

    Full Text Available A novel solution method to control the diameter of ZnO nanorods is reported. Small diameter (2-3 nm nanorods were synthesized from trihexylamine, and large diameter (50–80 nm nanorods were synthesized by increasing the alkyl chain length to tridodecylamine. The defect (green emission of the photoluminescence (PL spectra of the nanorods varies with diameter, and can thus be controlled by the diameter control. The small ZnO nanorods have strong green emission, while the large diameter nanorods exhibit a remarkably suppressed green band. We show that this observation supports surface oxygen vacancies as the defect that gives rise to the green emission.

  5. A Comparative Study on Structural and Optical Properties of ZnO Micro-Nanorod Arrays Grown on Seed Layers Using Chemical Bath Deposition and Spin Coating Methods

    Directory of Open Access Journals (Sweden)

    Sibel MORKOÇ KARADENİZ

    2016-11-01

    Full Text Available In this study, Zinc Oxide (ZnO seed layers were prepared on Indium Tin Oxide (ITO substrates by using Chemical Bath Deposition (CBD method and Sol-gel Spin Coating (SC method. ZnO micro-nanorod arrays were grown on ZnO seed layers by using Hydrothermal Synthesis method. Seed layer effects of structural and optical properties of ZnO arrays were characterized. X-ray diffractometer (XRD, Scanning Electron Microscopy (SEM and Ultraviolet Visible (UV-Vis Spectrometer were used for analyses. ZnO micro-nanorod arrays consisted of a single crystalline wurtzite ZnO structure for each seed layer. Besides, ZnO rod arrays were grown smoothly and vertically on SC seed layer, while ZnO rod arrays were grown randomly and flower like structures on CBD seed layer. The optical absorbance peaks found at 422 nm wavelength in the visible region for both ZnO arrays. Optical bandgap values were determined by using UV-Vis measurements at 3.12 and 3.15 eV for ZnO micro-nanorod arrays on CBD seed layer and for ZnO micro-nanorod arrays on SC-seed layer respectively.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.13443

  6. Single crystalline ZnO nanorods grown by a simple hydrothermal process

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.Z., E-mail: lzpei1977@163.com [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Lab of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Zhao, H.S. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Lab of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Tan, W. [Henkel Huawei Electronics Co. Ltd., Lian' yungang, Jiangsu 222006 (China); Yu, H.Y. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Lab of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Chen, Y.W. [Department of Materials Science, Fudan University, Shanghai 200433 (China); Zhang Qianfeng [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Lab of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China)

    2009-09-15

    Single crystalline ZnO nanorods with wurtzite structure have been prepared by a simple hydrothermal process. The microstructure and composition of the products were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray spectrum (EDS) and Raman spectrum. The nanorods have diameters ranging from 100 nm to 800 nm and length of longer than 10 {mu}m. Raman peak at 437.8 cm{sup -1} displays the characteristic peak of wurtzite ZnO. Photoluminescence (PL) spectrum shows a blue light emission at 441 nm, which is related to radiative recombination of photo-generated holes with singularly ionized oxygen vacancies.

  7. Single crystalline ZnO nanorods grown by a simple hydrothermal process

    International Nuclear Information System (INIS)

    Pei, L.Z.; Zhao, H.S.; Tan, W.; Yu, H.Y.; Chen, Y.W.; Zhang Qianfeng

    2009-01-01

    Single crystalline ZnO nanorods with wurtzite structure have been prepared by a simple hydrothermal process. The microstructure and composition of the products were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray spectrum (EDS) and Raman spectrum. The nanorods have diameters ranging from 100 nm to 800 nm and length of longer than 10 μm. Raman peak at 437.8 cm -1 displays the characteristic peak of wurtzite ZnO. Photoluminescence (PL) spectrum shows a blue light emission at 441 nm, which is related to radiative recombination of photo-generated holes with singularly ionized oxygen vacancies.

  8. Comparative study of ZnO nanorods and thin films for chemical and biosensing applications and the development of ZnO nanorods based potentiometric strontium ion sensor

    Science.gov (United States)

    Khun, K.; Ibupoto, Z. H.; Chey, C. O.; Lu, Jun.; Nur, O.; Willander, M.

    2013-03-01

    In this study, the comparative study of ZnO nanorods and ZnO thin films were performed regarding the chemical and biosensing properties and also ZnO nanorods based strontium ion sensor is proposed. ZnO nanorods were grown on gold coated glass substrates by the hydrothermal growth method and the ZnO thin films were deposited by electro deposition technique. ZnO nanorods and thin films were characterised by field emission electron microscopy [FESEM] and X-ray diffraction [XRD] techniques and this study has shown that the grown nanostructures are highly dense, uniform and exhibited good crystal quality. Moreover, transmission electron microscopy [TEM] was used to investigate the quality of ZnO thin film and we observed that ZnO thin film was comprised of nano clusters. ZnO nanorods and thin films were functionalised with selective strontium ionophore salicylaldehyde thiosemicarbazone [ST] membrane, galactose oxidase, and lactate oxidase for the detection of strontium ion, galactose and L-lactic acid, respectively. The electrochemical response of both ZnO nanorods and thin films sensor devices was measured by using the potentiometric method. The strontium ion sensor has exhibited good characteristics with a sensitivity of 28.65 ± 0.52 mV/decade, for a wide range of concentrations from 1.00 × 10-6 to 5.00 × 10-2 M, selectivity, reproducibility, stability and fast response time of 10.00 s. The proposed strontium ion sensor was used as indicator electrode in the potentiometric titration of strontium ion versus ethylenediamine tetra acetic acid [EDTA]. This comparative study has shown that ZnO nanorods possessed better performance with high sensitivity and low limit of detection due to high surface area to volume ratio as compared to the flat surface of ZnO thin films.

  9. Preparation of thin hexagonal highly-ordered anodic aluminum oxide (AAO) template onto silicon substrate and growth ZnO nanorod arrays by electrodeposition

    Science.gov (United States)

    Chahrour, Khaled M.; Ahmed, Naser M.; Hashim, M. R.; Elfadill, Nezar G.; Qaeed, M. A.; Bououdina, M.

    2014-12-01

    In this study, anodic aluminum oxide (AAO) templates of Aluminum thin films onto Ti-coated silicon substrates were prepared for growth of nanostructure materials. Hexagonally highly ordered thin AAO templates were fabricated under controllable conditions by using a two-step anodization. The obtained thin AAO templates were approximately 70 nm in pore diameter and 250 nm in length with 110 nm interpore distances within an area of 3 cm2. The difference between first and second anodization was investigated in details by in situ monitoring of current-time curve. A bottom barrier layer of the AAO templates was removed during dropping the voltage in the last period of the anodization process followed by a wet etching using phosphoric acid (5 wt%) for several minutes at ambient temperature. As an application, Zn nanorod arrays embedded in anodic alumina (AAO) template were fabricated by electrodeposition. Oxygen was used to oxidize the electrodeposited Zn nanorods in the AAO template at 700 °C. The morphology, structure and photoluminescence properties of ZnO/AAO assembly were analyzed using Field-emission scanning electron microscope (FESEM), Energy dispersive X-ray spectroscopy (EDX), Atomic force microscope (AFM), X-ray diffraction (XRD) and photoluminescence (PL).

  10. Synthesis and microstructural characterization of growth direction controlled ZnO nanorods using a buffer layer

    International Nuclear Information System (INIS)

    Park, Dong Jun; Kim, Dong Chan; Lee, Jeong Yong; Cho, Hyung Koun

    2006-01-01

    The growth direction and morphology of one-dimensional ZnO nanostructures grown by metal-organic chemical vapour deposition (MOCVD) were modulated by changing the growth temperature of previously deposited ZnO buffer layers that were used as a template. The ZnO nanorods grown on the low-temperature deposited buffer layer were regularly inclined with respect to the substrate surface and show in-plane alignment with azimuthally six-fold symmetry. In contrast, deposition of the buffer layer at higher growth temperature led to the formation of vertically well-aligned ZnO nanorods. In addition, the ZnO nanorods grown on the buffer layer deposited at low growth temperature show a growth direction of [1 0 1-bar 0], unlike the conventional ZnO nanorods showing a growth direction of [0001]. The microstructural analysis and atomic modelling of the formation of regularly inclined nanorods using transmission electron microscopy are presented

  11. Room temperature synthesis and optical properties of small diameter (5 nm) ZnO nanorod arrays.

    Science.gov (United States)

    Cho, Seungho; Jang, Ji-Wook; Lee, Jae Sung; Lee, Kun-Hong

    2010-10-01

    We report a simple wet-chemical synthesis of ∼5 nm diameter ZnO nanorod arrays at room temperature (20 °C) and normal atmospheric pressure (1 atm) and their optical properties. They were single crystalline in nature, and grew in the [001] direction. These small diameter ZnO nanorod arrays can also be synthesized at 0 °C. Control experiments were also conducted. On the basis of the results, we propose a mechanism for the spontaneous growth of the small diameter ZnO structures. The optical properties of the 5 nm diameter ZnO nanorod arrays synthesized using this method were probed by UV-Visible diffuse reflectance spectroscopy. A clear blue-shift, relative to the absorption band from 50 nm diameter ZnO nanorod arrays, was attributed to the quantum confinement effects caused by the small nanocrystal size in the 5 nm diameter ZnO nanorods.

  12. Tragacanth gum biopolymer as reducing and stabilizing agent in biosonosynthesis of urchin-like ZnO nanorod arrays: A low cytotoxic photocatalyst with antibacterial and antifungal properties.

    Science.gov (United States)

    Ghayempour, Soraya; Montazer, Majid; Mahmoudi Rad, Mahnaz

    2016-01-20

    Tragacanth, a natural gum, has been used for centuries as emulsifier, thickener, stabilizer and binder in various fields such as food, medical and cosmetic industries. In this study, Tragacanth gum was used as a clean and natural reducing and stabilizing agent for preparation of urchin-like ZnO nanorod arrays at low-temperature using ultrasonic irradiation. The morphology and structure of urchin-like ZnO nanorod arrays was investigated by XRD, FESEM images, EDX, UV-vis and FT-IR spectroscopy. The hexagonal zinc oxide nanorods were synthesized with the average diameter of 55-80 nm and length of 240 nm. The peak appeared in 447 cm(-1) in FTIR spectra and the peak around 362.3 nm in UV-vis spectra of ZnO nanorods confirmed the successful synthesis of ZnO nanorods. The urchin-like ZnO nanorod arrays indicated a good photocatalytic activity through degradation of methylene blue with 92.2% efficiency and rate constant of 0.0027 min(-1) at 120 min. Finally, the synthesized urchin-like ZnO nanorod arrays indicated 100% antibacterial activity against S. aureus and E. coli and 93% antifungal activity against C. albicans with a low cytotoxicity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Room temperature photoluminescence properties of ZnO nanorods grown by hydrothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Iwan, S., E-mail: iwan-sugihartono@unj.ac.id [Jurusan Fisika, FMIPA-UNJ, Rawamangun, Jakarta (Indonesia); Prodi Ilmu Material, Departemen Fisika, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Fauzia, Vivi [Prodi Ilmu Material, Departemen Fisika, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Umar, A. A. [Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, UKM Bangi, Selangor (Malaysia); Sun, X. W. [School of Electrical & Electronic Engineering, Nanyang Technological University, Nanyang Avenue (Singapore)

    2016-04-19

    Zinc oxide (ZnO) nanorods were fabricated by a hydrothermal reaction on silicon (Si) substrate at 95 °C for 6 hours. The ZnO seed layer was fabricated by depositing ZnO thin films on Si substrates by ultrasonic spray pyrolisis (USP). The annealing effects on crystal structure and optical properties of ZnO nanorods were investigated. The post-annealing treatment was performed at 800 °C with different environments. The annealed of ZnO nanorods were characterized by X-ray diffraction (XRD) and photoluminescence (PL) in order to analyze crystal structure and optical properties, respectively. The results show the orientations of [002], [101], [102], and [103] diffraction peaks were observed and hexagonal wurtzite structure of ZnO nanorods were vertically grown on Si substrates. The room temperature PL spectra show ultra-violet (UV) and visible emissions. The annealed of ZnO nanorods in vacuum condition (3.8 × 10{sup −3} Torr) has dominant UV emission. Meanwhile, non-annealed of ZnO nanorods has dominant visible emission. It was expected that the annealed of ZnO in vacuum condition suppresses the existence of native defects in ZnO nanorods.

  14. Highly transparent and UV-resistant superhydrophobic SiO2-coated ZnO nanorod arrays

    KAUST Repository

    Gao, Yangqin; Gereige, Issam; El Labban, Abdulrahman; Cha, Dong Kyu; Isimjan, Tayirjan T.; Beaujuge, Pierre

    2014-01-01

    Highly transparent and UV-resistant superhydrophobic arrays of SiO 2-coated ZnO nanorods are prepared in a sequence of low-temperature (<150 C) steps on both glass and thin sheets of PET (2 × 2 in. 2), and the superhydrophobic nanocomposite

  15. Photoluminescence of spray pyrolysis deposited ZnO nanorods

    Directory of Open Access Journals (Sweden)

    Mikli Valdek

    2011-01-01

    Full Text Available Abstract Photoluminescence of highly structured ZnO layers comprising well-shaped hexagonal rods is presented. The ZnO rods (length 500-1,000 nm, diameter 100-300 nm were grown in air onto a preheated soda-lime glass (SGL or ITO/SGL substrate by low-cost chemical spray pyrolysis method using zinc chloride precursor solutions and growth temperatures in the range of 450-550°C. We report the effect of the variation in deposition parameters (substrate type, growth temperature, spray rate, solvent type on the photoluminescence properties of the spray-deposited ZnO nanorods. A dominant near band edge (NBE emission is observed at 300 K and at 10 K. High-resolution photoluminescence measurements at 10 K reveal fine structure of the NBE band with the dominant peaks related to the bound exciton transitions. It is found that all studied technological parameters affect the excitonic photoluminescence in ZnO nanorods. PACS: 78.55.Et, 81.15.Rs, 61.46.Km

  16. Control of ZnO Nanorod Defects to Enhance Carrier Transportation in p-Cu₂O/i-ZnO Nanorods/n-IGZO Heterojunction.

    Science.gov (United States)

    Ke, Nguyen Huu; Trinh, Le Thi Tuyet; Mung, Nguyen Thi; Loan, Phan Thi Kieu; Tuan, Dao Anh; Truong, Nguyen Huu; Tran, Cao Vinh; Hung, Le Vu Tuan

    2017-01-01

    The p-Cu₂O/i-ZnO nanorods/n-IGZO heterojunctions were fabricated by electrochemical and sputtering method. ZnO nanorods were grown on conductive indium gallium zinc oxide (IGZO) thin film and then p-Cu₂O layer was deposited on ZnO nanorods to form the heterojunction. ZnO nanorods play an important role in carrier transport mechanisms and performance of the junction. The changing of defects in ZnO nanorods by annealing samples in air and vacuum have studied. The XRD, photoluminescence (PL) spectroscopy, and FTIR were used to study about structure, and defects in ZnO nanorods. The SEM, i–V characteristics methods were also used to define structure, electrical properties of the heterojunctions layers. The results show that the defects in ZnO nanorods affected remarkably on performance of heterojunctions of solar cells.

  17. Effect of Temperature and Growth Time on Vertically Aligned ZnO Nanorods by Simplified Hydrothermal Technique for Photoelectrochemical Cells.

    Science.gov (United States)

    Mohd Fudzi, Laimy; Zainal, Zulkarnain; Lim, Hong Ngee; Chang, Sook-Keng; Holi, Araa Mebdir; Sarif Mohd Ali, Mahanim

    2018-04-29

    Despite its large band gap, ZnO has wide applicability in many fields ranging from gas sensors to solar cells. ZnO was chosen over other materials because of its large exciton binding energy (60 meV) and its stability to high-energy radiation. In this study, ZnO nanorods were deposited on ITO glass via a simple dip coating followed by a hydrothermal growth. The morphological, structural and compositional characteristics of the prepared films were analyzed using X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet-visible spectroscopy (UV-Vis). Photoelectrochemical conversion efficiencies were evaluated via photocurrent measurements under calibrated halogen lamp illumination. Thin film prepared at 120 °C for 4 h of hydrothermal treatment possessed a hexagonal wurtzite structure with the crystallite size of 19.2 nm. The average diameter of the ZnO nanorods was 37.7 nm and the thickness was found to be 2680.2 nm. According to FESEM images, as the hydrothermal growth temperature increases, the nanorod diameter become smaller. Moreover, the thickness of the nanorods increase with the growth time. Therefore, the sample prepared at 120 °C for 4 h displayed an impressive photoresponse by achieving high current density of 0.1944 mA/cm².

  18. Fast vertical growth of ZnO nanorods using a modified chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae-hyun [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, Hyukhyun, E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, Won-Jae [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

    2014-06-01

    Highlights: • We grew vertical ZnO nanorods by a modified CBD process with a fast growth rate. • We studied the effects of the CBD process by varying growth temperature, time, and concentration. • The ZnO nanorods grown by the modified CBD showed good morphological and structural properties. - Abstract: In this study, we grew vertical ZnO nanorods on seeded Si (1 0 0) substrates using a modified chemical bath deposition (CBD). We investigated the effects of the growth temperature, growth time and concentration on the morphological and structural properties of the ZnO nanorods using field emission gun scanning electron microscopy (FEG-SEM) and X-ray diffraction. This modified CBD method shows improved results over conventional CBD. ZnO nanorods with good structural XRD properties were grown with a very fast growth rate in a wide range of growth conditions and did not require post-growth annealing.

  19. ZnO nanorod arrays grown under different pressures and their photoluminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Meng Xiuqing [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Graduate School of the Chinese Academy of Sciences (China); Zhao Dongxu [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China)]. E-mail: dxzhao2000@yahoo.com.cn; Shen Dezhen [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Zhang Jiying [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Li Binghui [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China); Wang Xiaohua [National Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and technology, 7089 Weixing Road Changchun (China); Fan Xiwu [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic ZoneChangchun 130033 (China)

    2007-01-15

    The ZnO nanorod arrays were synthesized via a simple vapor deposition method on Si (1 1 1) substrates at a low growth temperature of 520 deg. C. By selecting different source materials under different growth pressures, well-aligned hexagonal-shaped ZnO nanorod arrays were obtained under both conditions. X-ray diffraction (XRD) analysis confirmed the nanorods are c-axis orientated. Selected area electron diffraction (SAED) and transmission electron microscopy (TEM) analysis demonstrated the individual nanorod is single crystal. Photoluminescence (PL) analyses show the superior optical properties of the nanorod arrays.

  20. ZnO nanorod arrays grown under different pressures and their photoluminescence properties

    International Nuclear Information System (INIS)

    Meng Xiuqing; Zhao Dongxu; Shen Dezhen; Zhang Jiying; Li Binghui; Wang Xiaohua; Fan Xiwu

    2007-01-01

    The ZnO nanorod arrays were synthesized via a simple vapor deposition method on Si (1 1 1) substrates at a low growth temperature of 520 deg. C. By selecting different source materials under different growth pressures, well-aligned hexagonal-shaped ZnO nanorod arrays were obtained under both conditions. X-ray diffraction (XRD) analysis confirmed the nanorods are c-axis orientated. Selected area electron diffraction (SAED) and transmission electron microscopy (TEM) analysis demonstrated the individual nanorod is single crystal. Photoluminescence (PL) analyses show the superior optical properties of the nanorod arrays

  1. Annealing effects of ZnO nanorods on dye-sensitized solar cell efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Jooyoung; Lee, Juneyoung [Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Shinchon-dong, Seodaemoon-gu, Seoul 120-749 (Korea, Republic of); Lim, Sangwoo, E-mail: swlim@yonsei.ac.k [Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Shinchon-dong, Seodaemoon-gu, Seoul 120-749 (Korea, Republic of)

    2010-06-01

    Dye-sensitized solar cells (DSSCs) were fabricated using ZnO nanorod arrays vertically grown on fluorine-doped tin oxide (FTO) glass using a low-temperature hydrothermal method. When the ZnO seed layer was annealed, greater DSSC efficiency was obtained. This may be attributed to the improvement of adhesion between the FTO and the seed layer and the corresponding effective growth of the ZnO nanorods. The DSSCs fabricated using ZnO nanorods which underwent annealing were more efficient than those that did not undergo annealing. The ZnO nanorods which were annealed in N{sub 2}/H{sub 2} or O{sub 2} had increased dye loadings due to higher OH concentrations on the hydrophilic surface, which contributed to the improved DSSC efficiency. The fill factor increased after the annealing of the ZnO nanorods, potentially due to the improved crystallinity of the ZnO nanorods. In this study, annealing of both the seed layer and the ZnO nanorods resulted in the greatest DSSC efficiency.

  2. Y-Doped ZnO Nanorods by Hydrothermal Method and Their Acetone Gas Sensitivity

    Directory of Open Access Journals (Sweden)

    Peng Yu

    2013-01-01

    Full Text Available Pure and yttrium- (Y- doped (1 at%, 3 at%, and 7 at% ZnO nanorods were synthesized using a hydrothermal process. The crystallography and microstructure of the synthesized samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and energy dispersive X-ray spectroscopy (EDX. Comparing with pure ZnO nanorods, Y-doped ZnO exhibited improved acetone sensing properties. The response of 1 at% Y-doped ZnO nanorods to 100 ppm acetone is larger than that of pure ZnO nanorods. The response and recovery times of 1 at% Y-doped ZnO nanorods to 100 ppm acetone are about 30 s and 90 s, respectively. The gas sensor based on Y-doped ZnO nanorods showed good selectivity to acetone in the interfere gases of ammonia, benzene, formaldehyde, toluene, and methanol. The formation mechanism of the ZnO nanorods was briefly analyzed.

  3. Vertically aligned ZnO nanorods on porous silicon substrates: Effect of growth time

    Directory of Open Access Journals (Sweden)

    R. Shabannia

    2015-04-01

    Full Text Available Vertically aligned ZnO nanorods were successfully grown on porous silicon (PS substrates by chemical bath deposition at a low temperature. X-ray diffraction, field-emission scanning electron microscopy (FESEM, transmission electron microscopy (TEM, and photoluminescence (PL analyses were carried out to investigate the effect of growth duration (2 h to 8 h on the optical and structural properties of the aligned ZnO nanorods. Strong and sharp ZnO (0 0 2 peaks of the ZnO nanorods proved that the aligned ZnO nanorods were preferentially fabricated along the c-axis of the hexagonal wurtzite structure. FESEM images demonstrated that the ZnO nanorod arrays were well aligned along the c-axis and perpendicular to the PS substrates regardless of the growth duration. The TEM image showed that the top surfaces of the ZnO nanorods were round with a smooth curvature. PL spectra demonstrated that the ZnO nanorods grown for 5 h exhibited the sharpest and most intense PL peaks within the ultraviolet range among all samples.

  4. Temperature-dependent luminescence dynamics in ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Priller, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany)]. E-mail: heiko.priller@physik.uni-karlsruhe.de; Hauschild, R. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Zeller, J. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Klingshirn, C. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Kalt, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Kling, R. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Reuss, F. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Kirchner, Ch. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Waag, A. [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig (Germany)

    2005-04-15

    We report on an experimental study of the temporal photoluminescence dynamics of high-quality ZnO nanopillars from 10 K to room temperature. We find that defect states play an important role in the time evolution of the photoluminescence signal. At low excitation intensities capture into defects dominates the time dependence of the PL, at higher intensities they are saturated and the intrinsic excitation decay is observed. We separate the intrinsic exciton decay from the fast nonlinear M-band with the method of decay associated spectra and obtain the temperature dependence of the intrinsic exciton decay. High excitation measurements show a reduced exciton-exciton scattering in these thin nanorods.

  5. ZnO nanorod biosensor for highly sensitive detection of specific protein binding

    International Nuclear Information System (INIS)

    Kim, Jin Suk; Park, Won Il; Lee, Chul Ho; Yi, Gyu Chul

    2006-01-01

    We report on the fabrication of electrical biosensors based on functionalized ZnO nanorod surfaces with biotin for highly sensitive detection of biological molecules. Due to the clean interface and easy surface modification, the ZnO nanorod sensors can easily detect streptavidin binding down to a concentration of 25 nM, which is more sensitive than previously reported one-dimensional (1D) nanostructure electrical biosensors. In addition, the unique device structure with a micrometer-scale hole at the center of the ZnO nanorod's conducting channel reduces the leakage current from the aqueous solution, hence enhancing device sensitivity. Moreover, ZnO nanorod field-effect-transistor (FET) sensors may open up opportunities to create many other oxide nanorod electrical sensors for highly sensitive and selective real-time detection of a wide variety of biomolecules.

  6. Low-temperature growth of aligned ZnO nanorods: effect of annealing gases on the structural and optical properties.

    Science.gov (United States)

    Umar, Ahmad; Hahn, Yoon-Bong; Al-Hajry, A; Abaker, M

    2014-06-01

    Aligned ZnO nanorods were grown on ZnO/Si substrate via simple aqueous solution process at low-temperature of - 65 degrees C by using zinc nitrate and hexamethylenetetramine (HMTA). The detailed morphological and structural properties measured by FESEM, XRD, EDS and TEM confirmed that the as-grown nanorods are vertically aligned, well-crystalline possessing wurtzite hexagonal phase and grown along the [0001] direction. The room-temperature photoluminescence spectrum of the grown nanorods exhibited a strong and broad green emission and small ultraviolet emission. The as-prepared ZnO nanorods were post-annealed in nitrogen (N2) and oxygen (O2) environments and further characterized in terms of their morphological, structural and optical properties. After annealing the nanorods exhibit well-crystallinity and wurtzite hexagonal phase. Moreover, by annealing the PL spectra show the enhancement in the UV emission and suppression in the green emission. The presented results demonstrate that simply by post-annealing process, the optical properties of ZnO nanostructures can be controlled.

  7. Atom probe microscopy of zinc isotopic enrichment in ZnO nanorods

    Directory of Open Access Journals (Sweden)

    C. N. Ironside

    2017-02-01

    Full Text Available We report on atomic probe microscopy (APM of isotopically enriched ZnO nanorods that measures the spatial distribution of zinc isotopes in sections of ZnO nanorods for natural abundance natZnO and 64Zn and 66Zn enriched ZnO nanorods. The results demonstrate that APM can accurately quantify isotopic abundances within these nanoscale structures. Therefore the atom probe microscope is a useful tool for characterizing Zn isotopic heterostructures in ZnO. Isotopic heterostructures have been proposed for controlling thermal conductivity and also, combined with neutron transmutation doping, they could be key to a novel technology for producing p-n junctions in ZnO thin films and nanorods.

  8. Electrical properties of ZnO nanorods and layers

    Energy Technology Data Exchange (ETDEWEB)

    Schlenker, Eva; Bakin, Andrey; Peters, Ole; Mofor, Augustine C.; Postels, Bianca; El-Shaer, Hamid; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig (Germany); Weimann, Thomas; Hinze, Peter [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany)

    2007-07-01

    ZnO has attracted a lot of interest in the scientific community due to its outstanding properties. With a band gap of 3.37 eV and an exciton binding energy of 60 meV it is a promising candidate for micro- and optoelectronic applications. The growth of ZnO nanostructures and epitaxial layers is well under control and their optical and structural properties are already thoroughly characterized. However, due to contacting difficulties, less reports exist on the electrical properties of single ZnO nanostructures. In this contribution we present various contacting methods in order to explore the electrical properties of individual nanorods either grown by aqueous chemical growth or vapor phase transport. Current-Voltage characteristics were obtained by using an atomic force microscope with a conductive tip or by patterning contacts with e-beam lithography. The results are compared to the ones obtained from measurements on epitaxially grown ZnO layers and first applications are presented.

  9. Effects of thermal annealing temperature and duration on hydrothermally grown ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X.Q.; Kim, C.R.; Lee, J.Y.; Shin, C.M.; Heo, J.H.; Leem, J.Y. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, H. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of)], E-mail: hhryu@inje.ac.kr; Chang, J.H. [Major of Nano Semiconductor, Korea Maritime University, 1 Dongsam-dong, Yeongdo-Ku, Busan 606-791 (Korea, Republic of); Lee, H.C. [Department of Mechatronics Engineering, Korea Maritime University, 1 Dongsam-dong, Yeongdo-Ku, Busan 606-791 (Korea, Republic of); Son, C.S. [Department of Electronic Materials Engineering, Silla University, Gwaebeop-dong, Sasang-gu, Busan 617-736 (Korea, Republic of); Shin, B.C.; Lee, W.J. [Department of Nano Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of); Jung, W.G. [School of Advanced Materials Engineering, Kookmin University, 861-1, Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Tan, S.T. [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); Zhao, J.L. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Sun, X.W. [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

    2009-03-15

    In this study, the effects of thermal annealing temperature and duration on ZnO nanorod arrays fabricated by hydrothermal method were investigated. The annealed ZnO/Si(1 1 1) substrate was used for ZnO nanorod array growth. The effects of annealing treatment on the structural and optical properties were investigated by scanning electron microscopy, X-ray diffraction, and room-temperature photoluminescence measurements. With the annealing temperature of 750 {sup o}C and the annealing duration of 10 min, both the structural and optical properties of the ZnO nanorod arrays improved significantly, as indicated in the X-ray diffraction and photoluminescence measurement.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  11. The effects of addition of citric acid on the morphologies of ZnO nanorods

    International Nuclear Information System (INIS)

    Yang Zao; Liu Quanhui; Yang Lei

    2007-01-01

    ZnO nanorods of 25-100 nm in diameter and 0.2-1 μm in length were fabricated through citric acid assisted annealing process. The microstructure of ZnO nanorods was characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and field-emission scanning electron microscopy, respectively. As a result, it was found that ZnO nanorods were single crystalline and pure. The effects of the growth conditions such as addition of citric acid, annealing temperature on the morphologies of ZnO nanostructures have also been investigated. At the given temperature the length decreased but the diameter increased with addition of the mass of citric acid. With the rising of the calcining heat, the shape of ZnO changed from rod to granule for a given amount of citric acid. Finally, the mechanism for citric acid assisted annealing synthesis of the ZnO nanostructure is discussed

  12. Superior photocatalytic, electrocatalytic, and self-cleaning applications of Fly ash supported ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Thirumalai, Kuppulingam; Balachandran, Subramanian [Department of Chemistry, Annamalai University, Annamalainagar, 608 002, Tamil Nadu (India); Swaminathan, Meenakshisundaram, E-mail: chemres50@gmail.com [Department of Chemistry, Annamalai University, Annamalainagar, 608 002, Tamil Nadu (India); Nanomaterials Laboratory, International Research Centre, Kalasalingam Universty, Krihnankoil, 626126 (India)

    2016-11-01

    Ever growing research on modified semiconductor oxides made a significant progress in catalytic functional materials. In this article, we report the modification of ZnO photocatalyst by a simple hydrothermal decomposition method utilizing the cheaply available industrial waste fly ash. This modified Fly ash-ZnO photocatalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), high resolution transmission electron microscopy (HR-TEM), Atomic force microscopy (AFM), photoluminescence spectroscopy (PL) and diffuse reflectance spectroscopy (DRS). The XRD pattern indicates the presence of fly ash components and the hexagonal wurtzite structured ZnO. TEM images reveal well defined nanorod like structure. Reduction of photoluminescence intensity of Fly ash-ZnO at 418 nm, when compared to, prepared ZnO, indicates the suppression of recombination of the photogenerated electron–hole pair by loaded Fly ash on ZnO. Fly ash-ZnO exhibits enhanced photocatalytic activity for the degradation of azo dyes Reactive Orange 4, Rhodamine-B and Trypan Blue. This catalyst shows higher electrocatalytic activity than ZnO in the oxidation of methanol. Significant hydrophobicity of Fly ash-ZnO reveals its self cleaning property. - Highlights: • The degradation efficiency of Fly ash-ZnO under UV and Solar irradiation is greater than prepared ZnO and TiO{sub 2}‒P25. • Electrocatalytic activity of Fly ash-ZnO exhibits enhanced current production by methanol oxidation. • Fly ash-ZnO shows the high hydrophobicity than ZnO, it can be used as a self cleaning material for industrial applications.

  13. Electrodeposition of hierarchical ZnO nanorod arrays on flexible stainless steel mesh for dye-sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hui; Zhai, Xiangyang; Liu, Wenwu; Zhang, Mei; Guo, Min, E-mail: guomin@ustb.edu.cn

    2015-07-01

    Hierarchical ZnO nanorod arrays (ZNRAs) were synthesized on flexible stainless steel mesh (SSM) in large scale by a two-step facile electrodeposition method. The structure and morphology of the as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism of the ZnO hierarchical nanostructures was also discussed. Moreover, the effect of ZnO morphology on the photovoltaic performance of the flexible DSSCs based on SSM supported ZnO nanostructures was investigated in detail. It is shown that the flexible DSSCs exhibited a relatively higher power conversion efficiency of 1.11% compared with that based on primary ZNRAs. - Highlights: • Hierarchical ZnO nanorod arrays (ZNRAs) were prepared by electrodeposition method. • Flexible stainless steel mesh (SSM) supported with hierarchical ZNRAs was first used for DSSCs. • The effect of ZnO morphology on the photovoltaic performance of flexible DSSCs was investigated. • The DSSC based on 3-Hierarchical ZNRAs/ZNPs showed a relatively efficiency of 1.11%.

  14. Study of structural, morphological, optical and electroluminescent properties of undoped ZnO nanorods grown by a simple chemical precipitation

    Directory of Open Access Journals (Sweden)

    Singh A.

    2015-12-01

    Full Text Available In this work, zinc oxide (ZnO nanorods were obtained by a simple chemical precipitation method in the presence of capping agent: polyvinyl pyrrolidone (PVP at room temperature. X-ray diffraction (XRD result indicates that the synthesized undoped ZnO nanorods have hexagonal wurtzite structure without any impurities. It has been observed that the growth direction of the prepared ZnO nanorods is [1 0 1]. XRD analysis revealed that the nanorods have the crystallite size of 49 nm. Crystallite size is calculated by Debye-Scherrer formula and lattice strain is calculated by Williomson-Hall equation. Cell volume, Lorentz factor, Lorentz polarization factor, bond length, texture coefficient, lattice constants and dislocation density have also been studied. We also compared the interplanar spacings and relative peak intensities with their standard values at different angles. The scanning electron microscope (SEM images confirmed the size and shape of these nanorods. It has been found that the diameter of the nanorods ranges from 1.52 μm to 1.61 μm and the length is about 4.89 μm. It has also been observed that at room temperature ultraviolet visible (UV-Vis absorption band is around 355 nm (blue shifted as compared to the bulk. The average particle size has also been calculated by mathematical model of effective mass approximation equation, using UV-Vis absorption peak. Finally, the bandgap has been calculated using UV-absorption peak. Electroluminescence (EL studies show that emission of light is possible at very small threshold voltage and it increases rapidly with increasing applied voltage. It is seen that smaller ZnO nanoparticles give higher electroluminescence brightness starting at lower threshold voltage. The brightness is also affected by increasing the frequency of AC signal.

  15. Au sensitized ZnO nanorods for enhanced liquefied petroleum gas sensing properties

    International Nuclear Information System (INIS)

    Nakate, U.T.; Bulakhe, R.N.; Lokhande, C.D.; Kale, S.N.

    2016-01-01

    Highlights: • We studied ZnO nanorods film for liquefied petroleum gas (LPG) sensing. • The Au sensitization on ZnO nanorods gives improved LPG sensing response. • The Au–ZnO shows 48% LPG response for 1040 ppm with fast response time of 50 S. • We proposed schematic for sensing mechanism using band diagram. - Abstract: The zinc oxide (ZnO) nanorods have grown on glass substrate by spray pyrolysis deposition (SPD) method using zinc acetate solution. The phase formation, surface morphology and elemental composition of ZnO films have been investigated using X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX) techniques. The liquefied petroleum gas (LPG) sensing response was remarkably improved by sensitization of gold (Au) surface noble metal on ZnO nanorods film. Maximum LPG response of 21% was observed for 1040 ppm of LPG, for pure ZnO nanorods sample. After Au sensitization on ZnO nanorods film sample, the LPG response greatly improved up to 48% at operating temperature 623 K. The improved LPG response is attributed Au sensitization with spill-over mechanism. Proposed model for LPG sensing mechanism discussed.

  16. Au sensitized ZnO nanorods for enhanced liquefied petroleum gas sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Nakate, U.T., E-mail: umesh.nakate@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology, Deemed University, Pune 411025 (India); Bulakhe, R.N.; Lokhande, C.D. [Department of Physics, Thin films Physics Laboratory, Shivaji University Kolhapur 416004 (India); Kale, S.N. [Department of Applied Physics, Defence Institute of Advanced Technology, Deemed University, Pune 411025 (India)

    2016-05-15

    Highlights: • We studied ZnO nanorods film for liquefied petroleum gas (LPG) sensing. • The Au sensitization on ZnO nanorods gives improved LPG sensing response. • The Au–ZnO shows 48% LPG response for 1040 ppm with fast response time of 50 S. • We proposed schematic for sensing mechanism using band diagram. - Abstract: The zinc oxide (ZnO) nanorods have grown on glass substrate by spray pyrolysis deposition (SPD) method using zinc acetate solution. The phase formation, surface morphology and elemental composition of ZnO films have been investigated using X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX) techniques. The liquefied petroleum gas (LPG) sensing response was remarkably improved by sensitization of gold (Au) surface noble metal on ZnO nanorods film. Maximum LPG response of 21% was observed for 1040 ppm of LPG, for pure ZnO nanorods sample. After Au sensitization on ZnO nanorods film sample, the LPG response greatly improved up to 48% at operating temperature 623 K. The improved LPG response is attributed Au sensitization with spill-over mechanism. Proposed model for LPG sensing mechanism discussed.

  17. Superior photoelectrochemical properties of ZnO nanorods/poly(3-hexylthiophene) hybrid photoanodes

    Science.gov (United States)

    Majumder, T.; Hmar, J. J. L.; Dhar, S.; Mondal, S. P.

    2017-06-01

    Photoelectrochemical properties of ZnO nanorods (ZnO NRs) and poly(3-hexylthiophene) (P3HT) polymer hybrid photoanodes have been studied. The hybrid photoanodes demonstrated higher photoconversion efficiency, incident photon to current conversion efficiency (IPCE) and lower interfacial resistance compared to pristine ZnO nanorods and P3HT based electrodes. The origin of superior photoelectrochemical properties of ZnO/P3HT photoanodes has been explained using carrier transport mechanism at semiconductor/electrolyte junction. The stability of ZnO NRs/P3HT photoanode has been demonstrated.

  18. Hydrothermally grown ZnO nanorods on self-source substrate and their field emission

    International Nuclear Information System (INIS)

    Liu, J P; Xu, C X; Zhu, G P; Li, X; Cui, Y P; Yang, Y; Sun, X W

    2007-01-01

    Vertically aligned zinc oxide nanorod arrays were grown directly using a zinc foil as both source and substrate in pure water at low temperature by a simple hydrothermal reaction. The morphology and crystal structure of the ZnO nanorod arrays were examined by scanning electron microscopy, transmission electron microscopy and x-ray diffraction, respectively. The nanorods grew along the [0 0 0 1] direction and were 80 nm in diameter and almost 2 μm in length. Directly employing the zinc foil substrate as cathode, the field emission (FE) of the ZnO nanorods presented a two-stage slope behaviour in a ln(J/E 2 )-1/E plot according to the Fowler-Nordheim equation. The FE behaviour was investigated by considering the action of the defects in ZnO nanorods based on the measurement of the photoluminescence

  19. Electrical conduction and NO{sub 2} gas sensing properties of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Yasin [Council of Forensic Medicine, Bahçelievler, 34196 Istanbul (Turkey); Öztürk, Sadullah, E-mail: sadullahozturk@gyte.edu.tr [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); Kılınç, Necmettin [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); Koc University, Department of Electrical and Electronics Engineering, Sariyer, 34450 Istanbul (Turkey); Kösemen, Arif [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); Mus Alparslan University, Department of Physics, 49100 Mus (Turkey); Erkovan, Mustafa [SAKARYA University, Engineering Faculty, Department of Metallurgical and Materials Engineering, Esentepe Campus, 54187 Sakarya (Turkey); Öztürk, Zafer Ziya [Gebze Institute of Technology, Science Faculty, Department of Physics, 41400 Gebze, Kocaeli (Turkey); TÜBİTAK-Marmara Research Center, Materials Institute, 41470 Gebze, Kocaeli (Turkey)

    2014-06-01

    Thermally stimulated current (TSC), photoresponse and gas sensing properties of zinc oxide (ZnO) nanorods were investigated depending on heating rates, illumination and dark aging times with using sandwich type electrode system. Vertically aligned ZnO nanorods were grown on indium tin oxide (ITO) coated glass substrate by hydrothermal process. TSC measurements were performed at different heating rates under constant potential. Photoresponse and gas sensing properties were investigated in dry air ambient at 200 °C. For gas sensing measurements, ZnO nanorods were exposed to NO{sub 2} (100 ppb to 1 ppm) in dark and illuminated conditions and the resulting resistance transient was recorded. It was found from dark electrical measurements that the dependence of the dc conductivity on temperature followed Mott's variable range hopping (VRH) model. In addition, response time and recovery times of ZnO nanorods to NO{sub 2} gas decreased by exposing to white light.

  20. ZnO nanorods for simultaneous light trapping and transparent electrode application in solar cells

    KAUST Repository

    Khan, Yasser

    2011-10-01

    Efficacy of using vertically grown ZnO nanorod array in enhancing electromagnetic field intensity and serving as the top contact layer (transparent electrodes) for solar cells was investigated. © 2011 IEEE.

  1. Sub-coherent growth of ZnO nanorod arrays on three-dimensional graphene framework as one-bulk high-performance photocatalyst

    Science.gov (United States)

    Yu, Mei; Ma, Yuxiao; Liu, Jianhua; Li, Xinjie; Li, Songmei; Liu, Shenyao

    2016-12-01

    Highly ordered ZnO nanorod arrays were grown vertically on the surface of three-dimensional graphene (3DG) framework bulk to prepare a one-bulk structure. In such structure, ZnO exhibits outstanding photocatalyst performance due to its hybridization with 3DG. The sub-coherency between ZnO and 3DG ensures the template-free growth of ZnO nanorod arrays and the exposing of its most active crystal surfaces {0001}. The hybridization prevents the agglomeration of ZnO nanoparticles, helping the formation of nanorod array morphology, enhancing the mass transfer of reactants and the separation of photogenerated holes. In the efficiency test, with tiny amount of ZnO catalyst (∼5.03 × 10-3 g), the concentration of methyl orange decreased to ∼11% of the initial value within four hours. The structure possesses high average photocatalytic efficiency of 6.56 × 10-3 h-1, much higher than that of bare ZnO nanorods.

  2. Aqueous chemical growth of free standing vertical ZnO nanoprisms, nanorods and nanodiskettes with improved texture co-efficient and tunable size uniformity

    Energy Technology Data Exchange (ETDEWEB)

    Ram, S.D.G. [Bharath Niketan Engineering College, Department of Physics, Aundipatti (India); Ravi, G.; Mahalingam, T. [Alagappa University, Department of Physics, Karaikudi (India); Athimoolam, A. [Fatima Michael College of Engineering and Technology, Department of Physics, Madurai (India); Kulandainathan, M.A. [Central Electro Chemical Research Institute, Karaikudi (India)

    2011-12-15

    Tuning the morphology, size and aspect ratio of free standing ZnO nanostructured arrays by a simple hydrothermal method is reported. Pre-coated ZnO seed layers of two different thicknesses ({approx}350 nm or 550 nm) were used as substrates to grow ZnO nanostructures for the study. Various parameters such as chemical ambience, pH of the solution, strength of the Zn{sup 2+} atoms and thickness of seed bed are varied to analyze their effects on the resultant ZnO nanostructures. Vertically oriented hexagonal nanorods, multi-angular nanorods, hexagonal diskette and popcorn-like nanostructures are obtained by altering the experimental parameters. All the produced nanostructures were analysed by X-ray powder diffraction analysis and found to be grown in the (002) orientation of wurtzite ZnO. The texture co-efficient of ZnO layer was improved by combining a thick seed layer with higher cationic strength. Surface morphological studies reveal various nanostructures such as nanorods, diskettes and popcorn-like structures based on various preparation conditions. The optical property of the closest packed nanorods array was recorded by UV-VIS spectrometry, and the band gap value simulated from the results reflect the near characteristic band gap of ZnO. The surface roughness profile taken from the Atomic Force Microscopy reveals a roughness of less than 320 nm. (orig.)

  3. Room temperature growth of ZnO nanorods by hydrothermal synthesis

    Science.gov (United States)

    Tateyama, Hiroki; Zhang, Qiyan; Ichikawa, Yo

    2018-05-01

    The effect of seed layer morphology on ZnO nanorod growth at room temperature was studied via hydrothermal synthesis on seed layers with different thicknesses and further annealed at different temperatures. The change in the thickness and annealing temperature enabled us to control over a diameter of ZnO nanorods which are attributed to the changing of crystallinity and roughness of the seed layers.

  4. Crystallinity improvement of ZnO nanorods by optimization of low-cost electrodeposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Özdal, Teoman, E-mail: teomanozdal@hotmail.com; Taktakoğlu, Renna; Özdamar, Havva; Esen, Mehmet; Takçı, Deniz Kadir; Kavak, Hamide

    2015-10-01

    Extremely low-cost electrodeposition technique was developed to deposit ZnO nanorods. The growth process was performed using standard DC power supply, milliammeter and two-electrode electrochemical cell. The deposition was carried out on indium tin oxide (ITO) coated glass substrates by changing deposition parameters such as cathodic deposition current and time, solution molarity and temperature. The parameters varied to obtain optimum transparent semiconductor material for optoelectronic applications. Structural characterizations by X-ray diffraction (XRD) indicate the formation of polycrystalline phase ZnO with strong c-axis orientation and were sensitive to deposition temperatures and molarity as well. Average optical transmittance for the best two ZnO nanorod series was around 60% and 42%, respectively. The optical energy band gap of the ZnO nanorods decreased from 3.24 eV to 3.21 eV as the deposition time increased. All the nanorods were n-type with a high carrier concentration of 1 × 10{sup 20} cm{sup −3} and low 1–2 × 10{sup −3} Ωcm resistivity. - Highlights: • n-Type ZnO nanorods were electrochemically deposited employing standard DC power supply and milliammeter. • ZnO nanorods show very good polycrystalline and electrical properties consistent with the literature. • ZnO nanorod structures are hexagonal wurtzite and highly oriented along the c-axis perpendicular to the substrates. • Produced ZnO nanorod structures show good transparent conductive oxide properties.

  5. ZnO nanorod array polydimethylsiloxane composite solid phase micro-extraction fiber coating: fabrication and extraction capability.

    Science.gov (United States)

    Wang, Dan; Wang, Qingtang; Zhang, Zhuomin; Chen, Guonan

    2012-01-21

    ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals.

  6. Performance Improvement of GaN-Based Flip-Chip White Light-Emitting Diodes with Diffused Nanorod Reflector and with ZnO Nanorod Antireflection Layer

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The GaN-based flip-chip white light-emitting diodes (FCWLEDs with diffused ZnO nanorod reflector and with ZnO nanorod antireflection layer were fabricated. The ZnO nanorod array grown using an aqueous solution method was combined with Al metal to form the diffused ZnO nanorod reflector. It could avoid the blue light emitted out from the Mg-doped GaN layer of the FCWLEDs, which caused more blue light emitted out from the sapphire substrate to pump the phosphor. Moreover, the ZnO nanorod array was utilized as the antireflection layer of the FCWLEDs to reduce the total reflection loss. The light output power and the phosphor conversion efficiency of the FCWLEDs with diffused nanorod reflector and 250 nm long ZnO nanorod antireflection layer were improved from 21.15 mW to 23.90 mW and from 77.6% to 80.1% in comparison with the FCWLEDs with diffused nanorod reflector and without ZnO nanorod antireflection layer, respectively.

  7. ZnO nanorods/AZO photoanode for perovskite solar cells fabricated in ambient air

    Science.gov (United States)

    La Ferrara, Vera; De Maria, Antonella; Rametta, Gabriella; Della Noce, Marco; Vittoria Mercaldo, Lucia; Borriello, Carmela; Bruno, Annalisa; Delli Veneri, Paola

    2017-08-01

    ZnO nanorods are a good candidate for replacing standard photoanodes, such as TiO2, in perovskite solar cells and in principle superseding the high performances already obtained. This is possible because ZnO nanorods have a fast electron transport rate due to their large surface area. An array of ZnO nanorods is grown by chemical bath deposition starting from Al-doped ZnO (AZO) used both as a seed layer and as an efficient transparent anode in the visible spectral range. In particular, in this work we fabricate methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells using glass/AZO/ZnO nanorods/perovskite/Spiro-OMeTAD/Au as the architecture. The growth of ZnO nanorods has been optimized by varying the precursor concentrations, growth time and solution temperature. All the fabrication process and photovoltaic characterizations have been carried out in ambient air and the devices have not been encapsulated. Power conversion efficiency as high as 7.0% has been obtained with a good stability over 20 d. This is the highest reported value to the best of our knowledge and it is a promising result for the development of perovskite solar cells based on ZnO nanorods and AZO.

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

    Directory of Open Access Journals (Sweden)

    Jinzhang Liu

    2014-04-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  10. An approach to fabricating chemical sensors based on ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Park, Jae Young; Song, Dong Eon; Kim, Sang Sub

    2008-01-01

    Vertically and laterally aligned ZnO nanorod arrays were synthesized on Pt-coated Si substrates by catalyst-free metal organic chemical vapor deposition. An approach to fabricating chemical sensors based on the nanorod arrays using a coating-and-etching process with a photo-resist is reported. Tests of the devices as oxygen gas sensors have been performed. Our results demonstrate that the approach holds promise for the realization of sensitive and reliable nanorod array chemical sensors

  11. Study of annealing effect on the growth of ZnO nanorods on ZnO seed layers

    Science.gov (United States)

    Sannakashappanavar, Basavaraj S.; Pattanashetti, Nandini A.; Byrareddy, C. R.; Yadav, Aniruddh Bahadur

    2018-04-01

    A zinc oxide (ZnO) seed layer was deposited on the SiO2/Si substrate by RF sputtering. To study the effect of annealing, the seed layers were classified into annealed and unannealed thin films. Annealing of the seed layers was carried at 450°C. Surface morphology of the seed layers were studied by Atomic force microscopy. ZnO nanorods were then grown on both the types of seed layer by hydrothermal method. The morphology and the structural properties of the nanorods were characterized by X-ray diffraction and Scanning electron microscopy. The effect of seed layer annealing on the growth and orientation of the ZnO nanorods were clearly examined on comparing with the nanorods grown on unannealed seed layer. The nanorods grown on annealed seed layers were found to be well aligned and oriented. Further, the I-V characteristic study was carried out on these aligned nanorods. The results supports positively for the future work to further enhance the properties of developed nanorods for their wide applications in electronic and optoelectronic devices.

  12. Photo-stimulated resistive switching of ZnO nanorods

    International Nuclear Information System (INIS)

    Park, Jinjoo; Lee, Seunghyup; Yong, Kijung

    2012-01-01

    Resistive switching memory devices are promising candidates for emerging memory technologies because they yield outstanding device performance. Storage mechanisms for achieving high-density memory applications have been developed; however, so far many of them exhibit typical resistive switching behavior from the limited controlling conditions. In this study, we introduce photons as an unconventional stimulus for activating resistive switching behaviors. First, we compare the resistive switching behavior in light and dark conditions to describe how resistive switching memories can benefit from photons. Second, we drive the switching of resistance not by the electrical stimulus but only by the modulation of photon. ZnO nanorods were employed as a model system to demonstrate photo-stimulated resistive switching in high-surface-area nanomaterials, in which photo-driven surface states strongly affect their photoconductivity and resistance states. (paper)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  14. A comparison study between ZnO nanorods coated with graphene oxide and reduced graphene oxide

    International Nuclear Information System (INIS)

    Ding, Jijun; Wang, Minqiang; Deng, Jianping; Gao, Weiyin; Yang, Zhi; Ran, Chenxin; Zhang, Xiangyu

    2014-01-01

    Highlights: • Optical properties between ZnO-GO and ZnO-RGO composites were compared. • Photoluminescence quenching was observed in ZnO-GO composites. • We obtained enhanced photoluminescence in ZnO-RGO composites. -- Abstract: ZnO nanorods (ZnO NRs) coated with graphene oxide (ZnO-GO) and reduced graphene oxide sheets (ZnO-RGO) were prepared on indium tin oxide (ITO) substrates. The crystal structures, morphology and optical properties were analyzed by using X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) images, absorption spectra and photoluminescence (PL) spectra, respectively. A comparison between PL properties from ZnO-GO and ZnO-RGO were studied. Results indicated that the peak at 442 nm and a broad band at 450–600 nm of ZnO NRs show PL quenching after coating with GO sheets. As coating with RGO sheets, the extent of PL quenching increases. It is interesting to note that as ZnO NRs coated with RGO sheets, the intensity of PL peak at 390 nm significantly increased. The enhanced PL emission research in ZnO-RGO is directed toward development of the “nextgeneration” optoelectronics devices related with graphene materials

  15. Homogeneous vertical ZnO nanorod arrays with high conductivity on an in situ Gd nanolayer

    KAUST Repository

    Flemban, Tahani H.; Singaravelu, Venkatesh; Devi, Assa Aravindh Sasikala; Roqan, Iman S.

    2015-01-01

    We demonstrate a novel, one-step, catalyst-free method for the production of size-controlled vertical highly conductive ZnO nanorod (NR) arrays with highly desirable characteristics by pulsed laser deposition using a Gd-doped ZnO target. Our study

  16. A two-step obtainment of quantum confinement in ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Mofor, A C; El-Shaer, A; Suleiman, M; Bakin, A; Waag, A [Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany)

    2006-10-14

    ZnO nanorod-based single quantum well heterostructures were fabricated in a two-step process. Nanorods were first grown using vapour transport. Subsequently, high-quality ZnO/Zn{sub 0.85}Mg{sub 0.15}O heterostructures were grown on the nanorods using molecular beam epitaxy. The nanorods are well aligned along the c-axis of ZnO, as indicated by a very narrow rocking curve full width at half maximum. Quantum confinement was clearly observed within the ZnO well for different well widths. The quantum wells show photoluminescence peaks with a full width at half maximum as small as 15 meV.

  17. Electroluminescence and rectifying properties of heterojunction LEDs based on ZnO nanorods

    International Nuclear Information System (INIS)

    Rout, Chandra Sekhar; Rao, C N R

    2008-01-01

    n-ZnO NR/p-Si and n-ZnO NR/p-PEDOT/PSS heterojunction light-emitting diodes (LEDs) have been fabricated with ZnO nanorods (NRs) grown by a low-temperature method as well as by employing pulsed laser deposition (PLD). The low-temperature method involves growing the ZnO nanorods by the reaction of water with zinc metal. The current-voltage (I-V) characteristics of the heterojunctions show good rectifying diode characteristics. The electroluminescence (EL) spectra of the nanorods show an emission band at around 390 nm and defect related bands in the 400-550 nm region. Room-temperature electroluminescence is detected under forward bias for both the heterostructures. With the low-temperature grown nanorods, the defect related bands in the 400-550 nm range are more intense in the EL spectra, whereas with the PLD grown nanorods, only the 390 nm band is prominent

  18. Morphology development and oriented growth of single crystalline ZnO nanorod

    International Nuclear Information System (INIS)

    Wu Lili; Wu Youshi; Lue Wei; Wei Huiying; Shi Yuanchang

    2005-01-01

    Single crystalline ZnO nanorods were achieved by the assembly of nanocrystallines in tens of nanometer under hydrothermal conditions with the assistance of surfactant cetyltrimethylammonium bromide (CTAB). The obtained nanorod has rough surface as a result of oriented attachment growth. Transmission electron microscope (TEM) images showed the morphology evolution of the nanorod at different reaction time. Defects were observed and porous structure was left after the assembly of hundreds of nanocrystalline building blocks. Effect of pH condition on the morphology of the nanorod was also investigated

  19. Structural, optical and magnetic characterization of Ru doped ZnO nanorods

    International Nuclear Information System (INIS)

    Kumar, Sanjeev; Kaur, Palvinder; Chen, C.L.; Thangavel, R.; Dong, C.L.; Ho, Y.K.; Lee, J.F.; Chan, T.S.; Chen, T.K.; Mok, B.H.; Rao, S.M.; Wu, M.K.

    2014-01-01

    Graphical abstract: Ruthenium (Ru = 0%, 1% and 2%) doped nano-crystalline zinc oxide (ZnO) nanorods were synthesized by using well-known sol–gel technique. X-ray diffraction (XRD) results show that Ru (0%, 1% and 2%) doped ZnO nanorods crystallized in the wurtzite structure having space group C 3v (P6 3 mc). Williamson and Hall plot reveal that in the nanoscale dimensions, incorporation of Ru induced the tensile strain in ZnO host matrix. Photoluminescence (PL) and Raman studies of Ru doped ZnO nanorods show the formation of singly ionized oxygen vacancies which may account for the observed room temperature ferromagnetism (RTFM) in 2% Ru doped ZnO. X-ray absorption spectroscopy (XAS) reveals that Ru replace the Zn atoms in the host lattice and maintain the crystal symmetry with slightly lattice distortion. Highlights: • Ru doped ZnO nanorods crystallized in the wurtzite structure having space group C 3v (P6 3 mc). • PL and Raman studies show the formation of singly ionized oxygen vacancies in 2% Ru doped ZnO. • XAS reveals that Ru replace the Zn atoms in the host lattice with slightly lattice distortion. • Doping of Ru in ZnO nanostructures gives rise to RTFM ordering. -- Abstract: Ruthenium (Ru = 0%, 1% and 2%) doped nano-crystalline zinc oxide (ZnO) nanorods were synthesized by using well-known sol–gel technique. X-ray diffraction (XRD) results show that Ru (0%, 1% and 2%) doped ZnO nanorods crystallized in the wurtzite structure having space group C 3v (P6 3 mc). Williamson and Hall plot reveal that in the nanoscale dimensions, incorporation of Ru induced the tensile strain in ZnO host matrix. Photoluminescence (PL) and Raman studies of Ru doped ZnO nanorods show the formation of singly ionized oxygen vacancies which may account for the observed room temperature ferromagnetism (RTFM) in 2% Ru doped ZnO. X-ray absorption spectroscopy (XAS) reveals that Ru replace the Zn atoms in the host lattice and maintain the crystal symmetry with slightly lattice

  20. Synthesis and optical properties of flower-like ZnO nanorods by thermal evaporation method

    International Nuclear Information System (INIS)

    Zheng, J.H.; Jiang, Q.; Lian, J.S.

    2011-01-01

    Flower-like ZnO nanorods have been synthesized by heating a mixture of ZnO/graphite powders using the thermal evaporation and vapor transport on Si (1 0 0) substrates without any catalyst. The structures, morphologies and optical properties of the products were characterized in detail by using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Raman spectroscopy. The synthesized products consisted of large quantities of flower-like ZnO nanostructures in the form of uniform nanorods. The flower-like ZnO nanorods had high purity and well crystallized wurtzite structure, whose high crystalline quality was proved by Raman spectroscopy. The as-synthesized flower-like ZnO nanorods showed a strong ultraviolet emission at 386 nm and a weak and broad yellow-green emission in visible spectrum in its room temperature photoluminescence (PL) spectrum. In addition, the growth mechanism of the flower-like ZnO nanorods was discussed based on the reaction conditions.

  1. Comparative PL study of individual ZnO nanorods, grown by APMOCVD and CBD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Khranovskyy, Volodymyr, E-mail: volkh@ifm.liu.se [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, 58183 Linkoeping (Sweden); Yakimova, Rositza; Karlsson, Fredrik; Syed, Abdul S.; Holtz, Per-Olof [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, 58183 Linkoeping (Sweden); Nigussa Urgessa, Zelalem [Department of Physics, P.O Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Samuel Oluwafemi, Oluwatobi [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag XI 5117 (South Africa); Reinhardt Botha, Johannes [Department of Physics, P.O Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-05-15

    The photoluminescence properties of individual ZnO nanorods, grown by atmospheric pressure metalorganic chemical vapor deposition (APMOCV) and chemical bath deposition (CBD) are investigated by means of temperature dependent micro-PL. It was found that the low temperature PL spectra are driven by neutral donor bound exciton emission D{sup 0}X, peaked at 3.359 and 3.363 eV for APMOCVD and CBD ZnO nanorods, respectively. The temperature increase causes a red energy shift of the peaks and enhancement of the free excitonic emission (FX). The FX was found to dominate after 150 K for both samples. It was observed that while APMOCVD ZnO nanorods possess a constant low signal of visible deep level emission with temperature, the ZnO nanorods grown by CBD revealed the thermal activation of deep level emission (DLE) after 130 K. The resulting room temperature DLE was a wide band located at 420-550 nm. The PL properties of individual ZnO nanorods can be of importance for their forthcoming application in future optoelectronics and photonics.

  2. Comparative PL study of individual ZnO nanorods, grown by APMOCVD and CBD techniques

    International Nuclear Information System (INIS)

    Khranovskyy, Volodymyr; Yakimova, Rositza; Karlsson, Fredrik; Syed, Abdul S.; Holtz, Per-Olof; Nigussa Urgessa, Zelalem; Samuel Oluwafemi, Oluwatobi; Reinhardt Botha, Johannes

    2012-01-01

    The photoluminescence properties of individual ZnO nanorods, grown by atmospheric pressure metalorganic chemical vapor deposition (APMOCV) and chemical bath deposition (CBD) are investigated by means of temperature dependent micro-PL. It was found that the low temperature PL spectra are driven by neutral donor bound exciton emission D 0 X, peaked at 3.359 and 3.363 eV for APMOCVD and CBD ZnO nanorods, respectively. The temperature increase causes a red energy shift of the peaks and enhancement of the free excitonic emission (FX). The FX was found to dominate after 150 K for both samples. It was observed that while APMOCVD ZnO nanorods possess a constant low signal of visible deep level emission with temperature, the ZnO nanorods grown by CBD revealed the thermal activation of deep level emission (DLE) after 130 K. The resulting room temperature DLE was a wide band located at 420–550 nm. The PL properties of individual ZnO nanorods can be of importance for their forthcoming application in future optoelectronics and photonics.

  3. Bioanalytical system for detection of cancer cells with photoluminescent ZnO nanorods

    Science.gov (United States)

    Viter, R.; Jekabsons, K.; Kalnina, Z.; Poletaev, N.; Hsu, S. H.; Riekstina, U.

    2016-11-01

    Using photoluminescent ZnO nanorods and carbohydrate marker SSEA-4, a novel cancer cell recognition system was developed. Immobilization of SSEA-4 antibodies (αSSEA-4) on ZnO nanorods was performed in buffer solution (pH = 7.1) over 2 h. The cancer cell line probes were fixed on the glass slide. One hundred microliters of ZnO-αSSEA-4 conjugates were deposited on the cell probe and exposed for 30 min. After washing photoluminescence spectra were recorded. Based on the developed methodology, ZnO-αSSEA-4 probes were tested on patient-derived breast and colorectal carcinoma cells. Our data clearly show that the carbohydrate SSEA-4 molecule is expressed on cancer cell lines and patient-derived cancer cells. Moreover, SSEA-4 targeted ZnO nanorods bind to the patient-derived cancer cells with high selectivity and the photoluminescence signal increased tremendously compared to the signal from the control samples. Furthermore, the photoluminescence intensity increase correlated with the extent of malignancy in the target cell population. A novel portable bioanalytical system, based on optical ZnO nanorods and fiber optic detection system was developed. We propose that carbohydrate SSEA-4 specific ZnO nanorods could be used for the development of cancer diagnostic biosensors and for targeted therapy.

  4. ZnO Nano-Rod Devices for Intradermal Delivery and Immunization.

    Science.gov (United States)

    Nayak, Tapas R; Wang, Hao; Pant, Aakansha; Zheng, Minrui; Junginger, Hans; Goh, Wei Jiang; Lee, Choon Keong; Zou, Shui; Alonso, Sylvie; Czarny, Bertrand; Storm, Gert; Sow, Chorng Haur; Lee, Chengkuo; Pastorin, Giorgia

    2017-06-15

    Intradermal delivery of antigens for vaccination is a very attractive approach since the skin provides a rich network of antigen presenting cells, which aid in stimulating an immune response. Numerous intradermal techniques have been developed to enhance penetration across the skin. However, these methods are invasive and/or affect the skin integrity. Hence, our group has devised zinc oxide (ZnO) nano-rods for non-destructive drug delivery. Chemical vapour deposition was used to fabricate aligned nano-rods on ZnO pre-coated silicon chips. The nano-rods' length and diameter were found to depend on the temperature, time, quality of sputtered silicon chips, etc. Vertically aligned ZnO nano-rods with lengths of 30-35 µm and diameters of 200-300 nm were selected for in vitro human skin permeation studies using Franz cells with Albumin-fluorescein isothiocyanate (FITC) absorbed on the nano-rods. Fluorescence and confocal studies on the skin samples showed FITC penetration through the skin along the channels formed by the nano-rods. Bradford protein assay on the collected fluid samples indicated a significant quantity of Albumin-FITC in the first 12 h. Low antibody titres were observed with immunisation on Balb/c mice with ovalbumin (OVA) antigen coated on the nano-rod chips. Nonetheless, due to the reduced dimensions of the nano-rods, our device offers the additional advantage of excluding the simultaneous entrance of microbial pathogens. Taken together, these results showed that ZnO nano-rods hold the potential for a safe, non-invasive, and painless intradermal drug delivery.

  5. Synthesis of ZnO nanorods by spray pyrolysis for H2S gas sensor

    International Nuclear Information System (INIS)

    Shinde, S.D.; Patil, G.E.; Kajale, D.D.; Gaikwad, V.B.; Jain, G.H.

    2012-01-01

    Highlights: ► Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique. ► ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H 2 S gas (100 ppm) at 50 °C. ► This ZnO thin film has potential in application of room temperature H 2 S gas sensing. - Abstract: Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique (SPT). The equal amount of methanol and water is used as a solvent to dissolve the AR grade Zinc acetate for precursor solution. This solution is sprayed on to the glass substrate heated at 350 °C. The films were characterized by ultra-violet spectroscopy (UV), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The deposition of thin films results in a layer comprising well-shaped hexagonal ZnO nanorods with diameter of 90–120 nm and length of up to 200 nm. The gas sensing properties of these films have been investigated for various interfering gases such as CO 2 , CO, ethanol, NH 3 and H 2 S, etc. at operating temperature from 30° (room temperature) to 450 °C. The results indicate that the ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H 2 S gas (100 ppm) at 50 °C. The hexagonal pillar shaped ZnO nanorods can improve the sensitivity and selectivity of the sensors.

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

    Directory of Open Access Journals (Sweden)

    Sue Hung-Jue

    2011-01-01

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

  7. Growth of high-density ZnO nanorods on wood with enhanced photostability, flame retardancy and water repellency

    Science.gov (United States)

    Kong, Lizhuo; Tu, Kunkun; Guan, Hao; Wang, Xiaoqing

    2017-06-01

    Zinc oxide (ZnO) nanorod arrays were successfully assembled on the wood surface in situ via a two-step process consisting of formation of ZnO seeds and subsequent crystal growth under hydrothermal conditions at a low temperature. The morphology and crystalline structure of the formed ZnO nanorods were studied by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). Highly dense and uniform arrays of ZnO nanorods with well-defined hexagonal facets were generated on the wood surface by tuning the concentration of the ZnO growth solution during the hydrothermal treatment. Accelerated weathering tests indicated that the assembled ZnO nanorod arrays were highly protective against UV radiation and greatly enhanced the photostability of the coated wood. Meanwhile, the ZnO nanorod-coated wood can withstand continuous exposure to flame with only minor smoldering in contrast with the pristine wood catching fire easily and burning rapidly. Moreover, when further modified with low-surface-energy stearic acid, the ZnO nanorod decorated wood surface can be transformed into a superhydrophobic surface, with a water contact angle (CA) of ∼154°. Such ZnO nanorod-modified woods with enhanced photostability, flame retardancy and water repellency offer an interesting alternative to conventional wood preservation strategies, highlighting their potential applications in some novel wood products.

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

    Science.gov (United States)

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

    2016-04-20

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

  9. Carrier transport mechanisms of hybrid ZnO nanorod-polymer LEDs

    International Nuclear Information System (INIS)

    Cho, Sungjae; Lee, Kyuseung; Son, Dongick; Oh, Youngjei; Choi, Wonkook; Angadi, Basavaraj

    2014-01-01

    A hybrid polymer-nanorod (NR) light-emitting diode (LED), consisting of a hole-conducting polymer poly (9-vinyl carbazole) (PVK) and ZnO nanorod (NR) composite, with the device structure of glass/indium-tin-oxide (ITO)/PEDOT:PSS/(PVK + ZnO nanorods)/Al is fabricated through a simple spin coating technique. TEM images shows inhomogeneous deposition and the agglomeration of ZnO NRs, which is explained through their low probability of adsorption on PVK due to two-dimensional structural property. In the current-voltage characteristics, negative differential resistance (NDR) phenomenon is observed corresponding to device structure without ZnO NRs. The carrier transport behavior in the LED device is well described by both ohmic and space-charge-limited-current (SCLC) mechanisms. Broad blue electroluminescence (EL) consisting of two sub peaks, are centered at 441 nm and the other at 495 nm, is observed, which indicates that the ZnO nanorod play a role as a recombination center for excitons. The red shift in the position of the EL compared to that photoluminescence is well explained through band offsets at the heterojunction between the PVK and ZnO NRs.

  10. The sensitivity and dynamic response of field ionization gas sensor based on ZnO nanorods

    International Nuclear Information System (INIS)

    Min Jiahua; Liang Xiaoyan; Wang Bin; Wang Linjun; Zhao Yue; Shi Weimin; Xia Yiben

    2011-01-01

    Field ionization gas sensors based on ZnO nanorods (50–300 nm in diameter, and 3–8 μm in length) with and without a buffer layer were fabricated, and the influence of the orientation of nano-ZnO on the ionization response of devices was discussed, including the sensitivity and dynamic response of the ZnO nanorods with preferential orientation. The results indicated that ZnO nanorods as sensor anode could dramatically decrease the breakdown voltage. The XRD and SEM images illustrated that nano-ZnO with a ZnO buffer layer displayed high c-axis orientation, which helps to significantly reduce the breakdown voltage. Device A based on ZnO nanorods with a ZnO buffer layer could distinguish toluene and acetone. The dynamic responses of device A to the NO x compounds presented the sensitivity of 0.045 ± 0.007 ppm/pA and the response speed within 17–40 s, and indicated a linear relationship between NO x concentration and current response at low NO x concentrations. In addition, the dynamic responses to benzene, isopropyl alcohol, ethanol, and methanol reveals that the device has higher sensitivity to gas with larger static polarizability and lower ionization energy.

  11. Patterned Well-Aligned ZnO Nanorods Assisted with Polystyrene Monolayer by Oxygen Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Hyun Ji Choi

    2016-08-01

    Full Text Available Zinc oxide is known as a promising material for sensing devices due to its piezoelectric properties. In particular, the alignment of ZnO nanostructures into ordered nanoarrays is expected to improve the device sensitivity due to the large surface area which can be utilized to capture significant quantities of gas particles. However, ZnO nanorods are difficult to grow on the quartz substrate with well-ordered shape. So, we investigated nanostructures by adjusting the interval distance of the arranged ZnO nanorods using polystyrene (PS spheres of various sizes (800 nm, 1300 nm and 1600 nm. In addition, oxygen plasma treatment was used to specify the nucleation site of round, patterned ZnO nanorod growth. Therefore, ZnO nanorods were grown on a quartz substrate with a patterned polystyrene monolayer by the hydrothermal method after oxygen plasma treatment. The obtained ZnO nanostructures were characterized by X-ray diffraction (XRD and field-emission scanning electron microscope (FE-SEM.

  12. Au-coated ZnO nanorods on stainless steel fiber for self-cleaning solid phase microextraction-surface enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo; Shi, Yu-e; Cui, Jingcheng; Liu, Zhen; Zhang, Xiaoli; Zhan, Jinhua, E-mail: jhzhan@sdu.edu.cn

    2016-06-07

    Solid phase microextraction-surface enhanced Raman spectroscopy (SPME–SERS), combining the pretreatment and determination functions, has been successfully used in environmental analysis. In this work, Au-coated ZnO nanorods were fabricated on stainless steel fiber as a self-cleaning SERS-active SPME fiber. The ZnO nanorods grown on stainless steel fiber were prepared via a simple hydrothermal approach. Then the obtained nanostructures were decorated with Au nanoparticles through ion-sputtering at room temperature. The obtained SERS-active SPME fiber is a reproducible sensitivity sensor. Taking p-aminothiophenol as the probe molecule, the RSD value of the SERS-active SPME fiber was 8.9%, indicating the fiber owned good uniformity. The qualitative and quantitative detection of crystal violet and malachite green was also achieved. The log–log plot of SERS intensity to crystal violet and malachite green concentration showed a good linear relationship. Meanwhile, this SERS-active SPME fiber can achieve self-cleaning owning to the excellent photocatalytic performance of ZnO nanorods. Crystal violet was still successfully detected even after five cycles, which indicated the high reproducibility of this SERS-active SPME fiber. - Graphical abstract: Au-coated ZnO NRs on stainless steel fiber were used as SERS-active SPME fiber with good extraction effect, high SERS sensitivity. Self-cleaning function of the fiber was achieved based on the photocatalytic degradation property of ZnO nanorods by UV irradiation. - Highlights: • Au-coated ZnO nanorods on stainless steel fiber as a SERS-active SPME fiber was fabricated. • The SERS-active SPME fiber can directly extract and detect the crystal violet and malachite green. • The SERS-active SPME fiber owns good extraction effect, and high SERS sensitivity. • Self-cleaning property of the fiber were achieved based on the photocatalytic degradation property of ZnO.

  13. Au-coated ZnO nanorods on stainless steel fiber for self-cleaning solid phase microextraction-surface enhanced Raman spectroscopy

    International Nuclear Information System (INIS)

    Li, Bo; Shi, Yu-e; Cui, Jingcheng; Liu, Zhen; Zhang, Xiaoli; Zhan, Jinhua

    2016-01-01

    Solid phase microextraction-surface enhanced Raman spectroscopy (SPME–SERS), combining the pretreatment and determination functions, has been successfully used in environmental analysis. In this work, Au-coated ZnO nanorods were fabricated on stainless steel fiber as a self-cleaning SERS-active SPME fiber. The ZnO nanorods grown on stainless steel fiber were prepared via a simple hydrothermal approach. Then the obtained nanostructures were decorated with Au nanoparticles through ion-sputtering at room temperature. The obtained SERS-active SPME fiber is a reproducible sensitivity sensor. Taking p-aminothiophenol as the probe molecule, the RSD value of the SERS-active SPME fiber was 8.9%, indicating the fiber owned good uniformity. The qualitative and quantitative detection of crystal violet and malachite green was also achieved. The log–log plot of SERS intensity to crystal violet and malachite green concentration showed a good linear relationship. Meanwhile, this SERS-active SPME fiber can achieve self-cleaning owning to the excellent photocatalytic performance of ZnO nanorods. Crystal violet was still successfully detected even after five cycles, which indicated the high reproducibility of this SERS-active SPME fiber. - Graphical abstract: Au-coated ZnO NRs on stainless steel fiber were used as SERS-active SPME fiber with good extraction effect, high SERS sensitivity. Self-cleaning function of the fiber was achieved based on the photocatalytic degradation property of ZnO nanorods by UV irradiation. - Highlights: • Au-coated ZnO nanorods on stainless steel fiber as a SERS-active SPME fiber was fabricated. • The SERS-active SPME fiber can directly extract and detect the crystal violet and malachite green. • The SERS-active SPME fiber owns good extraction effect, and high SERS sensitivity. • Self-cleaning property of the fiber were achieved based on the photocatalytic degradation property of ZnO.

  14. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx

    2015-07-15

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  16. Growth of high-density ZnO nanorods on wood with enhanced photostability, flame retardancy and water repellency

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Lizhuo; Tu, Kunkun; Guan, Hao [Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091 (China); Wang, Xiaoqing, E-mail: wangxq@caf.ac.cn [Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091 (China); Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091 (China)

    2017-06-15

    Highlights: • ZnO nanorod arrays were deposited on the wood surface via a hydrothermal process. • The assembled ZnO nanorod arrays greatly enhanced the photostability of wood. • The treated wood can sustain direct exposure to flame with only minor smoldering. • The ZnO-coated wood modified with stearic acid showed a superhydrophobic surface. - Abstract: Zinc oxide (ZnO) nanorod arrays were successfully assembled on the wood surface in situ via a two-step process consisting of formation of ZnO seeds and subsequent crystal growth under hydrothermal conditions at a low temperature. The morphology and crystalline structure of the formed ZnO nanorods were studied by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). Highly dense and uniform arrays of ZnO nanorods with well-defined hexagonal facets were generated on the wood surface by tuning the concentration of the ZnO growth solution during the hydrothermal treatment. Accelerated weathering tests indicated that the assembled ZnO nanorod arrays were highly protective against UV radiation and greatly enhanced the photostability of the coated wood. Meanwhile, the ZnO nanorod-coated wood can withstand continuous exposure to flame with only minor smoldering in contrast with the pristine wood catching fire easily and burning rapidly. Moreover, when further modified with low-surface-energy stearic acid, the ZnO nanorod decorated wood surface can be transformed into a superhydrophobic surface, with a water contact angle (CA) of ∼154°. Such ZnO nanorod-modified woods with enhanced photostability, flame retardancy and water repellency offer an interesting alternative to conventional wood preservation strategies, highlighting their potential applications in some novel wood products.

  17. Growth of high-density ZnO nanorods on wood with enhanced photostability, flame retardancy and water repellency

    International Nuclear Information System (INIS)

    Kong, Lizhuo; Tu, Kunkun; Guan, Hao; Wang, Xiaoqing

    2017-01-01

    Highlights: • ZnO nanorod arrays were deposited on the wood surface via a hydrothermal process. • The assembled ZnO nanorod arrays greatly enhanced the photostability of wood. • The treated wood can sustain direct exposure to flame with only minor smoldering. • The ZnO-coated wood modified with stearic acid showed a superhydrophobic surface. - Abstract: Zinc oxide (ZnO) nanorod arrays were successfully assembled on the wood surface in situ via a two-step process consisting of formation of ZnO seeds and subsequent crystal growth under hydrothermal conditions at a low temperature. The morphology and crystalline structure of the formed ZnO nanorods were studied by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). Highly dense and uniform arrays of ZnO nanorods with well-defined hexagonal facets were generated on the wood surface by tuning the concentration of the ZnO growth solution during the hydrothermal treatment. Accelerated weathering tests indicated that the assembled ZnO nanorod arrays were highly protective against UV radiation and greatly enhanced the photostability of the coated wood. Meanwhile, the ZnO nanorod-coated wood can withstand continuous exposure to flame with only minor smoldering in contrast with the pristine wood catching fire easily and burning rapidly. Moreover, when further modified with low-surface-energy stearic acid, the ZnO nanorod decorated wood surface can be transformed into a superhydrophobic surface, with a water contact angle (CA) of ∼154°. Such ZnO nanorod-modified woods with enhanced photostability, flame retardancy and water repellency offer an interesting alternative to conventional wood preservation strategies, highlighting their potential applications in some novel wood products.

  18. ZnO Nanorod-Induced Heteroepitaxial Growth of SOD Type Co-Based Zeolitic Imidazolate Framework Membranes for H2 Separation.

    Science.gov (United States)

    Nian, Pei; Li, Yujia; Zhang, Xiang; Cao, Yi; Liu, Haiou; Zhang, Xiongfu

    2018-01-31

    Up to now, the fabrication of well-intergrown Co-based zeolitic imidazolate framework (ZIF) membranes on porous tubular supports is still a major challenge. We report here a heteroepitaxial growth for preparing well-intergrown Co-based ZIFs (ZIF-67 and ZIF-9) tubular membranes with high performance and excellent thermal stability by employing a thin layer of ZnO nanorods acting as both nucleation centers and anchor sites for the growth of metal-organic framework membranes. The results show that well-intergrown Co-ZIF-67 and Co-ZIF-9 membranes are successfully achieved on the ZnO nanorod-modified porous ceramic tubes. This highly active heteroepitaxial growth may be attributed to the fact that the (Zn,Co) hydroxy double salt intermediate produced in situ from ZnO nanorods acts as heteroseeds and enables the uniform growth of Co-based membranes. The H 2 /CO 2 selectivity of the as-prepared Co-ZIF-9 tubular membrane could reach about 23.8 and the H 2 /CH 4 selectivity of Co-ZIF-67 tubular membrane is as high as 45.4. Moreover, the membranes demonstrate excellent stability because of the ZnO nanorods as linkers between the membrane and substrate.

  19. ZnO Nano-Rod Devices for Intradermal Delivery and Immunization

    Directory of Open Access Journals (Sweden)

    Tapas R. Nayak

    2017-06-01

    Full Text Available Intradermal delivery of antigens for vaccination is a very attractive approach since the skin provides a rich network of antigen presenting cells, which aid in stimulating an immune response. Numerous intradermal techniques have been developed to enhance penetration across the skin. However, these methods are invasive and/or affect the skin integrity. Hence, our group has devised zinc oxide (ZnO nano-rods for non-destructive drug delivery. Chemical vapour deposition was used to fabricate aligned nano-rods on ZnO pre-coated silicon chips. The nano-rods’ length and diameter were found to depend on the temperature, time, quality of sputtered silicon chips, etc. Vertically aligned ZnO nano-rods with lengths of 30–35 µm and diameters of 200–300 nm were selected for in vitro human skin permeation studies using Franz cells with Albumin-fluorescein isothiocyanate (FITC absorbed on the nano-rods. Fluorescence and confocal studies on the skin samples showed FITC penetration through the skin along the channels formed by the nano-rods. Bradford protein assay on the collected fluid samples indicated a significant quantity of Albumin-FITC in the first 12 h. Low antibody titres were observed with immunisation on Balb/c mice with ovalbumin (OVA antigen coated on the nano-rod chips. Nonetheless, due to the reduced dimensions of the nano-rods, our device offers the additional advantage of excluding the simultaneous entrance of microbial pathogens. Taken together, these results showed that ZnO nano-rods hold the potential for a safe, non-invasive, and painless intradermal drug delivery.

  20. Low temperature carving of ZnO nanorods into nanotubes for dye-sensitized solar cell application

    Energy Technology Data Exchange (ETDEWEB)

    Dehghan Nayeri, Fatemeh, E-mail: F.d.nayeri@ut.ac.ir; Kolahdouz, Mohammadreza; Asl-Soleimani, Ebrahim; Mohajerzadeh, S.

    2015-06-05

    Highlights: • Large scale arrays of highly oriented ZnO NTs have been fabricated and investigated. • The DSSCs made of these 2.5 μm NRs and NTs resulted in conversion efficiencies of 0.34% and 0.9%, respectively. • EIS measurements have demonstrated that the NTs could acquire a higher electron lifetime compared to NRs. • Twofold electron lifetime electron accompanied by half electron transport time for ZnO NTs compared to NRs. - Abstract: High aspect ratio zinc oxide (ZnO) nanotubes (NT) were synthesized based on a two-steps approach. In the first step, ZnO nanorod (NR) arrays were prepared by chemical bath deposition from an aqueous of zinc nitrate. In the second step, the cores of ZnO NRs were carved selectively in a KCl solution, resulting in the formation of a tubular structure. The influence of KCL concentration, temperature, and immersion time on the ZnO NT formation process was completely characterized and investigated. 12.5 μm NRs and NTs have been utilized to manufacture dye-sensitized solar cells (DSSCs) and as a result, conversion efficiencies of 1.06% and 2.87% were obtained, respectively. Electrochemical impedance spectroscopy measurements have demonstrated that the NTs could acquire a higher electron lifetime compared to NRs which causes a faster electron collection. The overall improvement in NT-based DSSC performance demonstrates a new approach to enhance the efficiency of dye-sensitized solar cells.

  1. Effect of immobilization technique on performance ZnO nanorods based enzymatic electrochemical glucose biosensor

    Science.gov (United States)

    Shukla, Mayoorika; Pramila; Palani, I. A.; Singh, Vipul

    2017-11-01

    In this paper, ZnO Nanorods (ZNR) have been synthesized over Platinum (Pt) coated glass substrate with in-situ addition KMnO4 during hydrothermal growth process. Significant variation in ZnO nanostructures was observed by KMnO4 addition during the growth. Glucose oxidase was later immobilized over ZNRs. The as-prepared ZNRs were further utilized for glucose detection by employing amperometric electrochemical transduction method. In order to optimize the performance of the prepared biosensor two different immobilization techniques i.e. physical adsorption and cross linking have been employed and compared. Further investigations suggest that immobilization via cross linking method resulted in the improvement of the biosensor performance, thereby significantly affecting the sensitivity and linear range of the fabricated biosensor. Among the two types of biosensors fabricated using ZNR, the best performance was shown by cross linked electrodes. The sensitivity for the same was found to be 17.7 mA-cm-2-M-1, along with a wide linear range of 0.5-8.5 mM.

  2. Reversible superhydrophobic-superhydrophilic transition of ZnO nanorod/epoxy composite films.

    Science.gov (United States)

    Liu, Yan; Lin, Ziyin; Lin, Wei; Moon, Kyoung Sik; Wong, C P

    2012-08-01

    Tuning the surface wettability is of great interest for both scientific research and practical applications. We demonstrated reversible transition between superhydrophobicity and superhydrophilicity on a ZnO nanorod/epoxy composite film. The epoxy resin serves as an adhesion and stress relief layer. The ZnO nanorods were exposed after oxygen reactive ion etching of the epoxy matrix. A subsequent chemcial treatment with fluoroalkyl and alkyl silanes resulted in a superhydrophobic surface with a water contact angle up to 158.4° and a hysteresis as low as 1.3°. Under UV irradiation, the water contact angle decreased gradually, and the surface eventually became superhydrophilic because of UV induced decomposition of alkyl silanes and hydroxyl absorption on ZnO surfaces. A reversible transition of surface wettability was realized by alternation of UV illumination and surface treatment. Such ZnO nanocomposite surface also showed improved mechanical robustness.

  3. Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

    Directory of Open Access Journals (Sweden)

    Rafal Pietruszka

    2014-02-01

    Full Text Available Selected properties of photovoltaic (PV structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100 are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%.

  4. Improving gas sensor properties of encapsulated ZnO nanorods for ethanol detection using ZnO:Cr layer as an encapsulated layer

    Directory of Open Access Journals (Sweden)

    S. Safa

    2017-11-01

    Full Text Available In this study, encapsulated ZnO nanorods with different amount of chromium (Cr dopant (0-4.5 at.% were prepared with hydrothermal method, and their sensitivities as gas sensors against ethanol vapor were investigated. Morphologies of samples were explored by field emission scanning electron microscope (FESEM which showed that encapsulation process increased the diameter of ZnO nanorods. Existence of Cr in ZnO nanorods structures was confirmed by Energy-dispersive X-ray spectroscopy (EDX. Based on X-ray diffraction (XRD analysis, the ZnO:Cr nanorods had wurtzite crystal structure, and adding Cr did not alter the crystal structure of ZnO. Electrical measurements revealed that current levels of samples were decreased by adding Cr, while the current level of the sample with 4.5 at.% was increased. This reduction could be attributed to the presence of Cr3+ ions, which led to decrease of charge carriers. Besides, due to the catalytic properties of Cr and its lower ionization energy than Zn, it was observed that Cr dopant improved the detection sensitivity of samples, and decreased the optimum operating temperature of samples. Among all samples, the most sensitivity (14 was obtained based on the sample with 1.5 at.% of Cr for 500 ppm ethanol vapor at the optimum temperature (250 . In fact, by encapsulating the samples, they became rougher, so the appropriate places to absorb and decompose of gas molecules are increased.

  5. Low-temperature hydrothermal synthesis of ZnO nanorods: Effects of zinc salt concentration, various solvents and alkaline mineralizers

    Energy Technology Data Exchange (ETDEWEB)

    Edalati, Khatereh, E-mail: kh_ed834@stu.um.ac.ir [Department of Metallurgical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad (FUM) Campus, Azadi Sq., Mashhad, Khorasan Razavi (Iran, Islamic Republic of); Shakiba, Atefeh [Department of Material Science and Metallurgy, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Vahdati-Khaki, Jalil; Zebarjad, Seyed Mojtaba [Department of Metallurgical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad (FUM) Campus, Azadi Sq., Mashhad, Khorasan Razavi (Iran, Islamic Republic of)

    2016-02-15

    Highlights: • We synthesized ZnO nanorods by a simple hydrothermal process at 60 °C. • Effects of zinc salt concentration, solvent and alkaline mineralizer was studied. • Increasing concentration of zinc salt changed ZnO nucleation system. • NaOH yielded better results in the production of nanorods in both solvents. • Methanol performed better in the formation of nanorods using the two mineralizers. - Abstract: ZnO has been produced using various methods in the solid, gaseous, and liquid states, and the hydrothermal synthesis at low temperatures has been shown to be an environmentally-friendly one. The current work utilizes a low reaction temperature (60 °C) for the simple hydrothermal synthesis of ZnO nanorod morphologies. Furthermore, the effects of zinc salt concentration, solvent type and alkaline mineralizer type on ZnO nanorods synthesis at a low reaction temperature by hydrothermal processing was studied. Obtained samples were analyzed using X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Increasing the concentration of the starting zinc salt from 0.02 to 0.2 M changed ZnO nucleation system from the homogeneous to the heterogeneous state. The XRD results confirmed the production hexagonal ZnO nanostructures of with a crystallite size of 40.4 nm. Varying the experimental parameters (mineralizer and solvent) yielded ZnO nanorods with diameters ranging from 90–250 nm and lengths of 1–2 μm.

  6. Hydrothermal synthesis of highly crystalline ZnO nanorod arrays: Dependence of morphology and alignment on growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Azzez, Shrook A., E-mail: shurouq44@yahoo.com [Institutes of Nano-Optoelectronic Research and Technology Laboratory (INOR), Ministry of Science and Technology, Baghdad (Iraq); Hassan, Z.; Alimanesh, M.; Rasheed, Hiba S.; Sabah, Fayroz A.; Abdulateef, Sinan A. [Institutes of Nano-Optoelectronic Research and Technology Laboratory (INOR), Ministry of Science and Technology, Baghdad (Iraq); Hassan, J. J. [Department of Physics, College of Science, University of Basrah, Basrah (Iraq)

    2016-07-06

    Highly oriented zinc oxide nanorod were successfully grown on seeded p-type silicon substrate by hydrothermal methode. The morphology and the crystallinty of ZnO c-axis (002) arrays were systematically studied using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) methods. The effect of seed layer pre-annealing on nanorods properties was explained according to the nucleation site of ZnO nanoparticles on silicon substrate. In addition, the variation of the equal molarity of zinc nitrate hexahydrate and hexamine concentrations in the reaction vessel play a crucial role related to the ZnO nanorods.

  7. CdS-Sensitized ZnO Nanorod Photoelectrodes: Photoelectrochemistry and Photoinduced Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Idriss Bedja

    2011-01-01

    Full Text Available Thin films of ZnO semiconductor nanorods (ZnO-nr of 6 μm length and thin ZnO nanoparticulate films (ZnO-np have been prepared and modified with Q-dots CdS for comparison study. PIA (photoinduced absorption spectroscopy, a multipurpose tool in the study of dye-sensitized solar cells, is used to study a quantum-dot-modified metal-oxide nanostrucutred electrode. Q-dot CdS-sensitized ZnO-nr (1D network sensitized photoelectrode has demonstrated best performances in both photoelectrical response (IPCE max = 92% and broadening response into far visible comparing to ZnO-np-based CdS solar cell. Preadsorbing ZnO-nr with ZnO-np does not bring further improvement. Time constant for electron injection into ZnO-nr conduction band was relatively fast decay of 6.5 ms, similar to TiO2-coated CdS, and proves at least a well pore filling of ZnO-nr film by ultrafine CdS particles. Unidirectional electron transfer mechanistic in ZnO-nr has played a major role in these performances.

  8. Large-scale manufacture of ZnO nanorods by flame spray pyrolysis

    International Nuclear Information System (INIS)

    Hembram, K.; Sivaprakasam, D.; Rao, T. N.; Wegner, K.

    2013-01-01

    Large quantities of ZnO nanorods (>3 kg/h throughput) were produced in the gas-phase by flame spray pyrolysis (FSP) of a zinc nitrate–ethanol precursor solution without employing any catalysts or dopants. The nanorods with diameters of 20–30 nm and aspect ratios as high as seven were collected as a dry powder. Several rods self-aligned by forming junctions at the basal planes, while some even assembled into tetrapods. The aspect ratio of the nanorods could be controlled by the concentration of the Zn ions in the starting precursor solution, its delivery rate, and the oxygen flow into the reactor. To the best of our knowledge, this is the first time that synthesis of high aspect ratio ZnO nanorods by FSP is reported. Previous lab-scale experiments always yielded rather spherical albeit slightly elongated nanoparticles unless dopants were added. Such a product powder was obtained here when the ethanol in the precursor solution was replaced by methanol at otherwise constant process conditions. This is attributed to different temperature–time histories of the particles in the flame based on which a mechanism for ZnO nanorod formation in spray flames is proposed.

  9. Ultrafast Formation of ZnO Nanorods via Seed-Mediated Microwave Assisted Hydrolysis Process

    International Nuclear Information System (INIS)

    Tan, S T; Yahaya, M; Yap, C C; Umar, A A; Salleh, M M

    2013-01-01

    One dimensional (1D) zinc oxide, ZnO nanostructures have shown promising results for usage in photodiode and optoelectronic device due to their high surface area. Faster and conventional method for synthesis ZnO nanorods has become an attention for researcher today. In this paper, ZnO nanorods have been successfully synthesized via two-step process, namely alcothermal seeding and seed-mediated microwave hydrolysis process. In typical process, the ZnO nanoseeds were grown in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate, Zn (NO 3 ).6H 2 O and hexamethylenetetramine, HMT. The growth process was carried inside the inverted microwave within 5- 20 s. The effect of growth parameters (i.e. concentration, microwave power, time reaction) upon the modification of ZnO morphology was studied. ZnO nanostructures were characterized by Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). The densities of nanorods were evaluated by the Image J analysis. It was found that the morphology (e.g. shape and size) of nanostructures has changed drastically with the increment of growth solution concentration. The density of ZnO nanorods was proven to increase with the increasing of reaction time and microwave power. We hypothesize that the microwave power might enhance the rate of nucleation and promote the faster nanostructure growth as compared with the normal heating condition due to the superheating phenomenon. This method might promote a new and faster alternative way in nanostructure growth which can be applied in currently existing application.

  10. Ultrafast Formation of ZnO Nanorods via Seed-Mediated Microwave Assisted Hydrolysis Process

    Science.gov (United States)

    Tan, S. T.; Umar, A. A.; Yahaya, M.; Yap, C. C.; Salleh, M. M.

    2013-04-01

    One dimensional (1D) zinc oxide, ZnO nanostructures have shown promising results for usage in photodiode and optoelectronic device due to their high surface area. Faster and conventional method for synthesis ZnO nanorods has become an attention for researcher today. In this paper, ZnO nanorods have been successfully synthesized via two-step process, namely alcothermal seeding and seed-mediated microwave hydrolysis process. In typical process, the ZnO nanoseeds were grown in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate, Zn (NO3).6H2O and hexamethylenetetramine, HMT. The growth process was carried inside the inverted microwave within 5- 20 s. The effect of growth parameters (i.e. concentration, microwave power, time reaction) upon the modification of ZnO morphology was studied. ZnO nanostructures were characterized by Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). The densities of nanorods were evaluated by the Image J analysis. It was found that the morphology (e.g. shape and size) of nanostructures has changed drastically with the increment of growth solution concentration. The density of ZnO nanorods was proven to increase with the increasing of reaction time and microwave power. We hypothesize that the microwave power might enhance the rate of nucleation and promote the faster nanostructure growth as compared with the normal heating condition due to the superheating phenomenon. This method might promote a new and faster alternative way in nanostructure growth which can be applied in currently existing application.

  11. Highly transparent and UV-resistant superhydrophobic SiO2-coated ZnO nanorod arrays

    KAUST Repository

    Gao, Yangqin

    2014-02-26

    Highly transparent and UV-resistant superhydrophobic arrays of SiO 2-coated ZnO nanorods are prepared in a sequence of low-temperature (<150 C) steps on both glass and thin sheets of PET (2 × 2 in. 2), and the superhydrophobic nanocomposite is shown to have minimal impact on solar cell device performance under AM1.5G illumination. Flexible plastics can serve as front cell and backing materials in the manufacture of flexible displays and solar cells. © 2014 American Chemical Society.

  12. Development of Galactose Biosensor Based on Functionalized ZnO Nanorods with Galactose Oxidase

    Directory of Open Access Journals (Sweden)

    K. Khun

    2012-01-01

    Full Text Available The fabrication of galactose biosensor based on functionalised ZnO nanorods is described. The galactose biosensor was developed by immobilizing galactose oxidase on ZnO nanorods in conjunction with glutaraldehyde as a cross-linker molecule. The IRAS study provided evidence for the interaction of galactose oxidase with the surface of ZnO nanorods. The electromotive force (EMF response of the galactose biosensor was measured by potentiometric method. We observed that the proposed biosensor has a linear detection range over a concentration range from 10 mM to 200 mM with good sensitivity of 89.10±1.23 mV/decade. In addition, the proposed biosensor has shown fast time response of less than 10 s and a good selectivity towards galactose in the presence of common interferents such as ascorbic acid, uric acid, glucose, and magnesium ions. The galactose biosensor based on galactose oxidase immobilized ZnO nanorods has a shelf life more than four weeks.

  13. Field electron emission improvement of ZnO nanorod arrays after Ar plasma treatment

    International Nuclear Information System (INIS)

    Li Chun; Fang Guojia; Yuan Longyan; Liu Nishuang; Li Jun; Li Dejie; Zhao Xingzhong

    2007-01-01

    Vertically well-aligned single crystal ZnO nanorod arrays were synthesized and enhanced field electron emission was achieved after radio-frequency (rf) Ar plasma treatment. With Ar plasma treatment for 30 min, flat tops of the as-grown ZnO nanorods have been etched into sharp tips without damaging ZnO nanorod geometrical morphologies and crystallinity. After the Ar ion bombardment, the emission current density increases from 2 to 20 μA cm -2 at 9.0 V μm -1 with a decrease in turn-on voltage from 7.1 to 4.8 V μm -1 at a current density of 1 μA cm -2 , which demonstrates that the field emission of the as-grown ZnO nanorods has been efficiently enhanced. The scanning electron microscopy (SEM) results, in conjunction with the results of transmission electron microscopy (TEM), Raman spectroscopy and photoluminescence observation, are used to investigate the mechanisms of the field emission enhancement. It is believed that the enhancements can be mainly attributed to the sharpening of rod tops, and the decrease of electrostatic screening effect

  14. Rapid growth of nanotubes and nanorods of würtzite ZnO through ...

    Indian Academy of Sciences (India)

    Administrator

    report here on the synthesis of ZnO nanorods and nano- tubes from a ..... Hu Y, Zhou X, Han Q, Cao Q and Huang Y 2003 Mater. Sci. ... Lao J Y, Huang J Y, Wang D Z and Ren Z F 2003 Nano Lett. 3. 235 ... Xing Y J et al 2003 Appl. Phys. Lett.

  15. Defects related room temperature ferromagnetism in Cu-implanted ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Li, D.; Li, D.K.; Wu, H.Z.; Liang, F.; Xie, W.; Zou, C.W.; Shao, L.X.

    2014-01-01

    Highlights: • Room temperature ferromagnetism was observed in Cu-implanted ZnO nanorod arrays. • Cu-implanted ZnO nanorods show a saturation magnetization value of 1.82 μ B /Cu. • The origin of ferromagnetism can be explained by the defects related bound magnetic polarons. -- Abstract: Room temperature ferromagnetism (FM) was observed in Cu-implanted ZnO nanorod arrays. The implantation dose for Cu ions was 1 × 10 16 cm −2 and the implantation energy was 100 keV. The ion implantation induced defects and disorder has been observed by the XRD, PL and TEM experiments. The PL spectrum revealed a dominant luminescence peaks at 390 nm and a broad and strong green emission at 500–700 nm, which is considered to be related to the ionized oxygen vacancy. Cu-implanted ZnO nanorods annealed at 500 °C show a saturation magnetization value of 1.82 μ B /Cu and a positive coercive field of 68 Oe. The carrier concentration is not much improved after annealing and in the order of 10 16 cm −3 , which suggests that FM does not depend upon the presence of a significant carrier concentration. The origin of ferromagnetism behavior can be explained on the basis of electrons and defects that form bound magnetic polarons, which overlap to create a spin-split impurity band

  16. The effects of surface stripping ZnO nanorods with argon bombardment

    International Nuclear Information System (INIS)

    Barnett, Chris J; Kryvchenkova, Olga; Maffeis, Thierry G G; Cobley, Richard J; Smith, Nathan A; Kelleher, Liam

    2015-01-01

    ZnO nanorods are used in devices including field effects transistors, piezoelectric transducers, optoelectronics and gas sensors. However, for efficient and reproducible device operation and contact behaviour, surface contaminants must be removed or controlled. Here we use low doses of argon bombardment to remove surface contamination and make reproducible lower resistance contacts. Higher doses strip the surface of the nanorods allowing intrinsic surface measurements through a cross section of the material. Photoluminescence finds that the defect distribution is higher at the near-surface, falling away in to the bulk. Contacts to the n-type defect-rich surface are near-Ohmic, whereas stripping away the surface layers allows more rectifying Schottky contacts to be formed. The ability to select the contact type to ZnO nanorods offers a new way to customize device behaviour. (paper)

  17. ZnO nanorods arrays with Ag nanoparticles on the (002) plane derived by liquid epitaxy growth and electrodeposition process

    International Nuclear Information System (INIS)

    Yin Xingtian; Que Wenxiu; Shen Fengyu

    2011-01-01

    Well-aligned ZnO nanorods (NRs) arrays with Ag nanoparticles (NPs) on the (002) plane are obtained by combining a liquid epitaxy technique with an electrodeposition process. Cyclic voltammetry study is employed to understand the electrochemical behaviors of the electrodeposition system, and potentiostatic method is employed to deposit silver NPs on the ZnO NRs in the electrolyte with an Ag + concentration of 1 mM. X-ray diffraction analysis is used to study the crystalline properties of the as-prepared samples, and energy dispersive X-ray is adopted to confirm the composition at the surface of the deposited samples. Results indicate only a small quantity of silver can be deposited on the surface of the samples. Effect of the deposition potential and time on the morphological properties of the resultant Ag NPs/ZnO NRs are investigated in detail. Scanning electron microscopy images and transmission electron microscopy images indicate that the Ag NPs deposited on the (002) plane of the ZnO NRs with a large dispersion in diameter can be obtained by a single potentiostatic deposition process, while dense Ag NPs with a much smaller diameter dispersion on the top of the ZnO NRs, most of which locate on the conical tip of the ZnO NRs, can be obtained by a two-potentiostatic deposition process, The mechanism of this deposition process is also suggested.

  18. Fabrication of ZnO nanorod using spray-pyrolysis and chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Ramadhani, Muhammad F., E-mail: brian@tf.itb.ac.id; Pasaribu, Maruli A. H., E-mail: brian@tf.itb.ac.id; Yuliarto, Brian, E-mail: brian@tf.itb.ac.id; Nugraha, E-mail: brian@tf.itb.ac.id [Advanced Functional Materials Laboratory, Engineering Physics Department Faculty of Industrial Technology, Institut Teknologi Bandung (Indonesia)

    2014-02-24

    ZnO thin films with nanorod structure were deposited using Ultrasonic Spray Pyrolysis method for seed growth, and Chemical Bath Deposition (CBD) for nanorod growth. High purity Zn-hydrate and Urea are used to control Ph were dissolved in ethanol and aqua bidest in Ultrasonic Spray Pyrolysis process. Glass substrate was placed above the heater plate of reaction chamber, and subsequently sprayed with the range duration of 5, 10 and 20 minutes at the temperatures of 3500 C. As for the Chemical Bath Deposition, the glass substrate with ZnO seed on the surface was immerse to Zn-hydrate, HMTA (Hexa Methylene Tetra Amine) and deionized water solution for duration of 3, 5 and 7 hour and temperatures of 600 C, washed in distilled water, dried, and annealed at 3500 C for an hour. The characterization of samples was carried out to reveal the surface morphology using Scanning Electron Microscopy (SEM). From the data, the combination of 5 minutes of Ultrasonic Spray Pyrolysis process and 3 hour of CBD has showed the best structure of nanorod. Meanwhile the longer Spraying process and CBD yield the bigger nanorod structure that have been made, and it makes the films more dense which make the nanorod collide each other and as a result produce unsymetric nanorod structure.

  19. Low Temperature Hydrothermal Growth of ZnO Nanorod Films for Schottky Diode Application

    International Nuclear Information System (INIS)

    Singh, Shaivalini; Park, Si-Hyun

    2016-01-01

    The purpose of this research is to report on the fabrication and characterizations of Pd/ZnO nanorod-based Schottky diodes for optoelectronic applications. ZnO nanorods (NRs) were grown on silicon (Si) substrates by a two step hydrothermal method. In the first step, a seed layer of pure ZnO was deposited from a solution of zinc acetate and ethyl alcohol, and then in the second step, the main growth of the ZnO NRs was done over the seed layer. The structural morphology and optical properties of the ZnO NR films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectroscopy. The electrical characterization of the Pd/ZnO NR contacts was studied using a current-voltage (I-V) tool. The ZnO NR films exhibited a wurtzite ZnO structure,and the average length of the ZnO NRs were in the range of 750 nm to 800 nm. The values of ideality factor, turn-on voltage and reverse saturation current were calculated from the I-V characteristics of Pd/ZnO NR-based Schottky diodes. The study demonstrates that Pd/ZnO NR Schottky contacts fabricated by a simple and inexpensive method can be used as a substitute for conventional Schottky diodes for optoelectronic applications.

  20. Calculation of DSSC parameters based on ZnO nanorod/TiO2 mesoporous photoanode

    Science.gov (United States)

    Safriani, L.; Nurrida, A.; Mulyana, C.; Susilawati, T.; Bahtiar, A.; Aprilia, A.

    2017-07-01

    Photoanode of dye sensitized solar cell (DSSC) plays an important role as electron transport media to accept photogenerated electron from excited state of dye. There are several physical properties that are required from photoanode of DSSC. It should be highly transparent, have large surface area, has a conduction band lower than LUMO of dye molecule, has high charge carrier mobility and finally has a good stability in redox electrolyte process. In this work, DSSC with structure FTO/ZnO nanorod/TiO2 mesoporous/Ru-dye/gel electrolyte/ Pt/FTO has been fabricated. In order to modified the structures of photoanode, ZnO nanorod was grown on aluminium doped ZnO seed layer by variation concentration of Al (0 wt%, 0.5 wt% and 1.0 wt%). Zinc nitrate hexahydrate and hexamethylenetetramine used as raw materials for ZnO nanorod growth solution and deposited by self-assembly methods on FTO/Al doped ZnO seed layer. It is then followed by deposition of titania (TiO2) paste by screen printing methods. DSSC parameters i.e. ideally factor (n), series resistance (RS ), and shunt resistance (RSH ) was derived from current density-voltage (I-V) curve using the simplify equation of ideal diode model. The influences of ZnO photoanode structures to the solar cell performance will be completely discussed.

  1. Effect of annealing temperature on surface morphology and work function of ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hainan [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Xue, Mingshan, E-mail: xuems04@mails.ucas.ac.cn [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Ou, Junfei [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Jiangsu Key Laboratory for Solar Cell Materials and Technology, Changzhou University, Changzhou 213164 (China); Wang, Fajun [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Li, Wen, E-mail: wenl@ualberta.ca [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

    2013-07-15

    Highlights: •The 600°C and 450°C isothermal sections of the Zn-Fe-B system are determined. •The solubility of Zn in Fe{sub 2}B and FeB at 600°C is 1.8 at.% and 2.5 at.%, respectively. •The solubility of Zn in Fe{sub 2}B and FeB at 450°C is 1.7 at.% and 2.1 at.%, respectively. •All Fe-Zn compounds can be in equilibrium with Fe{sub 2}B at 450°C. •Both FeB and Fe{sub 2}B are in equilibrium with the liquid phase at 600°C. -- Abstract: A simple and effective method of fabricating nanomaterials and the understanding of their electronic structures are significant for designing novel nanodevices. In this study, ZnO nanorod arrays on ITO substrate were synthesized by electrochemical deposition, and the effect of annealing temperature on surface morphology and especially work function was investigated using various techniques. The results indicated that the formation of hexagonal ZnO nanorod arrays with (0 0 0 1) orientation was strongly associated with the annealing temperature. The work function of well-aligned ZnO nanorod arrays is 4.84 eV, which shows an obvious dependence on the arrangement of ZnO nanorod arrays. These changes in work function of ZnO nanorod arrays (e.g., used as the photoanode of dye-sensitized solar cells) are important to understand the electron transport of related nanodevices.

  2. Ag nanoparticles-decorated ZnO nanorod array on a mechanical flexible substrate with enhanced optical and antimicrobial properties

    Science.gov (United States)

    Chen, Yi; Tse, Wai Hei; Chen, Longyan; Zhang, Jin

    2015-03-01

    Heteronanostructured zinc oxide nanorod (ZnO NR) array are vertically grown on polydimethylsiloxane (PDMS) through a hydrothermal method followed by an in situ deposition of silver nanoparticles (Ag NPs) through a photoreduction process. The Ag-ZnO heterostructured nanorods on PDMS are measured with an average diameter of 160 nm and an average length of 2 μm. ZnO NRs measured by high-resolution transmission electron microscope (HRTEM) shows highly crystalline with a lattice fringe of 0.255 nm, which corresponds to the (0002) planes in ZnO crystal lattice. The average diameter of the Ag NPs in situ deposited on the ZnO NRs is estimated at 22 ± 2 nm. As compared to the bare ZnO NRs, the heterostructured Ag-ZnO nanorod array shows enhanced ultraviolet (UV) absorption at 440 nm, and significant emission in the visible region (λem = 542 nm). In addition, the antimicrobial efficiency of Ag-ZnO heterostructured nanorod array shows obvious improvement as compared to bare ZnO nanorod array. The cytotoxicity of ZnO nanorod array with and without Ag NPs was studied by using 3 T3 mouse fibroblast cell line. No significant toxic effect is imposed on the cells.

  3. Polystyrene sphere monolayer assisted electrochemical deposition of ZnO nanorods with controlable surface density

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, D., E-mail: daniel.ramirez@ucv.c [Laboratorio de Electroquimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Gomez, H. [Laboratorio de Electroquimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Lincot, D. [Institute de Recherche et Developpement sur l' Energie Photovoltaique-IRDEP, 6 Quai Watier 78401, Chatou Cedex (France)

    2010-02-15

    In this paper we report the zinc oxide nanorods (ZnO NRs) growth by electrochemical deposition onto polycrystalline gold electrodes modified with assemblies of polystyrene sphere monolayers (PSSMs). Growth occurs through the interstitial spaces between the hexagonally close packed spheres. ZnO NRs nucleate in the region where three adjacent spheres leave a space, being able to grow and projected over the PSSMs. The nanorod surface density (N{sub NR}) shows a linear dependence with respect to a PS sphere diameter selected. XRD analysis shows these ZnO NRs are highly oriented along the (0 0 2) plane (c-axis). This open the possibility to have electronic devices with mechanically supported nanometric materials.

  4. Low temperature growth and properties of ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Wu, Xiang; Zheng, Yufeng; Chen, Huibo; Gong, Lihong; Qu, Fengyu

    2011-01-01

    In this paper, well aligned ZnO nanorod arrays were synthesized by a simple hydrothermal route at a low temperature. The diameters of the as-synthesized products were 20–60 nm and the lengths were as much as several micrometers. The surfaces and tops of the nanorods were smooth. The as-grown nanorod arrays were investigated by x-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL) spectroscopy and contact angle (CA) analysis. The as-grown nanorods were single crystalline structures with a wurtzite phase, and grew along the [0001] direction. The PL spectrum with only one strong peak at 383 nm shows good intrinsic emission

  5. 16.1% Efficient Hysteresis-Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays

    KAUST Repository

    Mahmood, Khalid; Swain, Bhabani Sankar; Amassian, Aram

    2015-01-01

    Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low-temperature solution-processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density

  6. Effects of the aspect ratio on the dye adsorption of ZnO nanorods grown by using a sonochemical method for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Choi, Seok Cheol; Yun, Won Suk; Sohn, Sang Ho; Oh, Sang Jin

    2012-01-01

    Well-aligned ZnO nanorods for the photoelectrode of dye-sensitized solar cells (DSSCs) were grown via a sonochemical method, and the effects of their aspect ratios on the dye adsorption in DSSCs were studied. The control of the aspect ratio of well-aligned ZnO nanorods was performed by tuning the mole concentration of zinc acetate dehydrate in the range of 0.04 ∼ 0.06M. The dye amounts adsorbed in the ZnO nanorods were estimated from the UV-Visible absorbance by using the Beer-Lambert law. The efficiency of DSSCs with ZnO nanorods was measured to investigate the effects of the aspect ratio of the ZnO nanorods on the dye adsorption properties. A change in the aspect ratio of the ZnO nanorods was founded to yield a change in their dye adsorption ability, resulting in a change in the efficiency of the DSSCs.

  7. Mechanism for wettability alteration of ZnO nanorod arrays via thermal annealing in vacuum and air

    International Nuclear Information System (INIS)

    Zhang Jun; Liu Yanru; Wei Zhiyang; Zhang Junyan

    2013-01-01

    Highlights: ► Oxygen vacancy is the key factor in accounting for the change in morphology of the ZnO nanorod arrays. ► We firstly investigated the wettability alteration of ZnO nanorod arrays annealed in vacuum at different temperature. ► The hydrophilicity of the ZnO nanorod arrays annealed in air is not related to the oxygen vacancy but ascribed to the O adatom on the nanorod surface. - Abstract: The ZnO nanorod arrays were synthesized via a simple hydrothermal process followed by annealing in vacuum and air respectively at different temperature. The wettability of samples was controlled by adjusting the annealing atmosphere and temperature. To investigate the mechanism of wettability alteration, the chemical composition and surface morphology of nanorod arrays were analyzed by X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM), respectively. Increasing oxygen vacancy concentration by increasing annealing temperature in vacuum resulted in a great change of surface morphology, which played the major role in wettability change. Under annealing in air, oxygen vacancy concentration reduced and the surface morphology of nanorod arrays showed little change with increasing annealing temperature. The wettability alteration is ascribed to the O adatom on the nanorods surface.

  8. Fabrication and Characterization of Highly Oriented N-Doped ZnO Nanorods by Selective Area Epitaxy

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2015-01-01

    Full Text Available High-quality nitrogen-doped ZnO nanorods have been selectively grown on patterned and bare ZnO templates by the combination of nanoimprint lithography and chemical vapor transport methods. The grown nanorods exhibited uniformity in size and orientation as well as controllable density and surface-to-volume ratio. The structural and optical properties of ZnO nanorods and the behaviour of N dopants have been investigated by means of the scanning electron microscope, photoluminescence (PL spectra, and Raman scattering spectra. The additional vibration modes observed in Raman spectra of N-doped ZnO nanorods provided solid evidence of N incorporation in ZnO nanorods. The difference of excitonic emissions from ZnO nanorods with varied density and surface-to-volume ratio suggested the different spatial distribution of intrinsic defects. It was found that the defects giving rise to acceptor-bound exciton (A0X emission were most likely to distribute in the sidewall surface with nonpolar characteristics, while the donor bound exciton (D0X emission related defects distributed uniformly in the near top polar surface.

  9. Surface potential driven dissolution phenomena of [0 0 0 1]-oriented ZnO nanorods grown from ZnO and Pt seed layers

    Science.gov (United States)

    Seo, Youngmi; Kim, Jung Hyeun

    2011-06-01

    Highly oriented ZnO nanorods are synthesized hydrothermally on ZnO and Pt seed layers, and they are dissolved in KOH solution. The rods grown on ZnO seed layer show uniform dissolution, but those grown on Pt seed layer are rod-selectively dissolved. The ZnO nanorods from both seed layers show the same crystalline structure through XRD and Raman spectrometer data. However, the surface potential analysis reveals big difference for ZnO and Pt seed cases. The surface potential distribution is very uniform for the ZnO seed case, but it is much fluctuated on the Pt seed case. It suggests that the rod-selective dissolution phenomena on Pt seed case are likely due to the surface energy difference.

  10. AuNPs Hybrid Black ZnO Nanorods Made by a Sol-Gel Method for Highly Sensitive Humidity Sensing

    Directory of Open Access Journals (Sweden)

    Hongyan Zhang

    2018-01-01

    Full Text Available A highly sensitive self-powered humidity sensor has been realized from AuNPs hybrid black zinc oxide (ZnO nanorods prepared through a sol-gel method. XRD pattern reveals that both ZnO and ZnO/AuNPs exhibit a wurtzite structure. ZnO/AuNPs nanorods grow in a vertical alignment, which possesses high uniformity and forms dense arrays with a smaller diameter than that of ZnO nanoparticles. All ZnO/AuNPs and pure black ZnO show lower band gap energy than the typically reported 3.34 eV of pure ZnO. Furthermore, the band gap of ZnO/AuNPs nanocomposites is effectively influenced by the amount of AuNPs. The humidity sensing tests clearly prove that all the ZnO/AuNPs humidity sensors exhibit much higher response than that of ZnO sensors, and the sensitivity of such ZnO/AuNPs nanorods (6 mL AuNPs display a change three orders higher than that of pure ZnO with relative humidity (RH ranging from 11% to 95% at room temperature. The response and recovery time of the ZnO/AuNPs are 5.6 s and 32.4 s, respectively. This study of the construction of semiconductor/noble metal sensors provides a rational way to control the morphology of semiconductor nanomaterials and to design a humidity sensor with high performance.

  11. Resonant exciton-phonon coupling in ZnO nanorods at room temperature

    Directory of Open Access Journals (Sweden)

    Soumee Chakraborty

    2011-09-01

    Full Text Available Vibronic and optoelectronic properties, along with detailed studies of exciton-phonon coupling at room temperature (RT for random and aligned ZnO nanorods are reported. Excitation energy dependent Raman studies are performed for detailed analysis of multi-phonon processes in the nanorods. We report here the origin of coupling between free exciton and its associated phonon replicas, including its higher order modes, in the photoluminescence spectra at RT. Resonance of excitonic electron and resonating first order zone center LO phonon, invoked strongly by Frolich interaction, are made responsible for the observed phenomenon.

  12. Photoelectrocatalytic activity of a hydrothermally grown branched Zno nanorod-array electrode for paracetamol degradation.

    Science.gov (United States)

    Lin, Chin Jung; Liao, Shu-Jun; Kao, Li-Cheng; Liou, Sofia Ya Hsuan

    2015-06-30

    Hierarchical branched ZnO nanorod (B-ZnR) arrays as an electrode for efficient photoelectrocatalytic degradation of paracetamol were grown on fluorine-doped tin oxide substrates using a solution route. The morphologic and structural studies show the ZnO trunks are single-crystalline hexagonal wurtzite ZnO with a [0001] growth direction and are densely covered by c-axis-oriented ZnO branches. The obvious enhancement in photocurrent response of the B-ZnR electrode was obtained than that in the ZnO nanoparticle (ZnO NP) electrode. For the photoelectrocatalytic degradation of paracetamol in 20 h, the conversion fraction of the drug increased from 32% over ZnO NP electrode to 62% over B-ZnR arrays with about 3-fold increase in initial reaction rate. The light intensity-dependent photoelectrocatalytic experiment indicated that the superior performance over the B-ZnR electrode was mainly ascribed to the increased specific surface area without significantly sacrificing the charge transport and pollutant diffusion efficiencies. Two aromatic intermediate compounds were observed and eventually converted into harmless carboxylic acids and ammonia. Hierarchical tree-like ZnO arrays can be considered effective alternatives to improve photoelectro degradation rates without the need for expensive additives. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. ZnO nanorods/polyaniline heterojunctions for low-power flexible light sensors

    Energy Technology Data Exchange (ETDEWEB)

    Talib, Rawnaq A.; Abdullah, M.J. [Nano-Optoelectronics Research and Technology (NOR) Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Penang (Malaysia); Al-Salman, Husam S. [Department of Physics, College of Science, University of Basrah, Basrah (Iraq); Mohammad, Sabah M. [Nano-Optoelectronics Research and Technology (NOR) Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Penang (Malaysia); Allam, Nageh K., E-mail: nageh.allam@aucegypt.edu [Energy Materials Laboratory (EML), School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835 (Egypt)

    2016-09-15

    Zinc oxide nanorods (ZnO NRs) were directly grown on p-type polyaniline (PAni)/polyethylene terephthalate (PET) using chemical bath deposition method at low temperature. Field emission scanning electron microscopy and X-ray diffraction techniques were used to study the morphology and structure of the fabricated films. The resulted ZnO NRs are hexagonal and grew vertically on the PAni surface in the (002) direction along the c-axis. The compressive strain, Raman and photoluminescence measurements confirmed the high-quality crystal structure of the formed ZnO NRs with no damage of the PAni surface. The photodetector made using ZnO NRs/PAni junction showed a sensitivity of 85% and a quantum efficiency of 12.3% at 5 V. - Highlights: • ZnO NRs/polyaniline p-n junction photodetectors were fabricated on flexible substrates. • The fabricated ZnO NRs grew along the (002) direction. • The fabricated ZnO NRs have low compressive strain. • The ZnO NRs/PAni junction showed a high sensitivity of 85%. • The photodetectors showed quantum efficiency as high as 12%.

  14. Effect of Zn(NO{sub 3}){sub 2} concentration in hydrothermal–electrochemical deposition on morphology and photoelectrochemical properties of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, Ceren, E-mail: ceryilmaz@ku.edu.tr [Koc University, Department of Chemistry, Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey); Unal, Ugur [Koc University, Department of Chemistry, Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey); Graduate School of Science and Engineering, Koc University, Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey); Koc University Surface Science and Technology Center (KUYTAM), Rumelifeneri yolu, Sariyer 34450, Istanbul (Turkey)

    2016-04-15

    Graphical abstract: - Highlights: • Combined hydrothermal–electrochemical deposition was used to grow ZnO films. • 1-D ZnO NRs are obtained even at high Zn(NO{sub 3}){sub 2} concentrations (1 mM < [Zn{sup 2+}] < 0.1 M). • Aspect ratio and alignment of ZnO NRs can be controlled by initial [Zn(NO{sub 3}){sub 2}]. • [Zn{sup 2+}] dependent structural and photoelectrochemical properties have been studied. • Photocurrent density exhibited by ZnO NRs increases with increasing aspect ratio. - Abstract: Zn(NO{sub 3}){sub 2} concentration had been reported to be significantly influential on electrodeposition of ZnO structures. In this work, this issue is revisited using hydrothermal–electrochemical deposition (HED). Seedless, cathodic electrochemical deposition of ZnO films is carried out on ITO electrode at 130 °C in a closed glass reactor with varying Zn(NO{sub 3}){sub 2} concentration. Regardless of the concentration of Zn{sup 2+} precursor (0.001–0.1 M) in the deposition solution, vertically aligned 1-D ZnO nanorods are obtained as opposed to electrodepositions at lower temperatures (70–80 °C). We also report the effects of high bath temperature and pressure on the photoelectrochemical properties of the ZnO films. Manipulation of precursor concentration in the deposition solution allows adjustment of the aspect ratio of the nanorods and the degree of texturation along the c-axis; hence photoinduced current density. HED is shown to provide a single step synthesis route to prepare ZnO rods with desired aspect ratio specific for the desired application just by controlling the precursor concentration.

  15. H2O2 sensing using HRP modified catalyst-free ZnO nanorods synthesized by RF sputtering

    Science.gov (United States)

    Srivastava, Amit; Kumar, Naresh; Singh, Priti; Singh, Sunil Kumar

    2017-06-01

    Catalyst-free ( 00 l) oriented ZnO nanorods (NRs) -based biosensor for the H2O2 sensing has been reported. The (002) oriented ZnO NRs as confirmed by X-ray diffraction were successfully grown on indium tin oxide (ITO) coated glass substrate by radio frequency (RF) sputtering technique without using any catalyst. Horseradish peroxidase (HRP) enzyme was immobilized on ZnO NRs by physical adsorption technique to prepare the biosensor. In this HRP/ZnO NR/ITO bioelectrode, nafion solution was added to form a tight membrane on surface. The prepared bioelectrode has been used for biosensing measurements by electrochemical analyzer. The electrochemical studies reveal that the prepared HRP/ZnO NR/ITO biosensor is highly sensitive to the detection of H2O2 over a linear range of 0.250-10 μM. The ZnO NR-based biosensor showed lower value of detection limit (0.125 μM) and higher sensitivity (13.40 µA/µM cm2) towards H2O2. The observed value of higher sensitivity attributed to larger surface area of ZnO nanostructure for effective loading of HRP besides its high electron communication capability. In addition, the biosensor also shows lower value of enzyme's kinetic parameter (Michaelis-Menten constant, K m) of 0.262 μM which indicates enhanced enzyme affinity of HRP to H2O2. The reported biosensor may be useful for various applications in biosensing, clinical, food, and beverage industry.

  16. Investigation of the Optimal Parameters in Hydrothermal Method for the Synthesis of ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Ying-Chung Chen

    2014-01-01

    Full Text Available We investigated a two-step method to deposit the ZnO-based nanostructure films, including nanorods and nanoflowers. In the first step, sputtering method was used to deposit the ZnO films on SiO2/Si substrates as the seed layer. In the second step, Zn(NO32–6H2O and C6H12N4 were used as precursors and hydrothermal process was used as the method to synthesize the ZnO films. After that, the ZnO films were measured by an X-ray diffraction pattern and a FESEM to analyze their crystallization and morphology. We had found that the ZnO films had three different morphologies synthesized on ZnO/SiO2/Si substrates, including irregular-plate structure films, nanorod films, and beautiful chrysanthemum-like clusters (nanoflower films. We would prove that the face direction of ZnO/SiO2/Si substrates in the hydrothermal bottle and deposition time were two important factors to influence the synthesized results of the ZnO films.

  17. Preparation of ZnS nanorods by ultrasonic waves

    International Nuclear Information System (INIS)

    Behboudnia, M.; Majlesara, M.H.; Khanbabaee, B.

    2005-01-01

    ZnS nanorods of approximately 1 μm in length and 20 nm in diameter have been prepared by sonicating ethylenediamine solution of elemental S and zinc acetate in presence of 1-decanthiol under air. The nanorods were characterized using techniques such as X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDAX) and UV-vis absorption spectroscopy. The as-prepared nanorods have regular shape, narrow size distribution and high purity, having band gap of 4.56 eV compared to 3.54 eV corresponding to its bulk single-crystal

  18. Selective Thallium (I Ion Sensor Based on Functionalised ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Z. H. Ibupoto

    2012-01-01

    Full Text Available Well controlled in length and highly aligned ZnO nanorods were grown on the gold-coated glass substrate by hydrothermal growth method. ZnO nanorods were functionalised with selective thallium (I ion ionophore dibenzyldiaza-18-crown-6 (DBzDA18C6. The thallium ion sensor showed wide linear potentiometric response to thallium (I ion concentrations ( M to  M with high sensitivity of 36.87 ± 1.49 mV/decade. Moreover, thallium (I ion demonstrated fast response time of less than 5 s, high selectivity, reproducibility, storage stability, and negligible response to common interferents. The proposed thallium (I ion-sensor electrode was also used as an indicator electrode in the potentiometric titration, and it has shown good stoichiometric response for the determination of thallium (I ion.

  19. Effect of growth time to the properties of Al-doped ZnO nanorod arrays

    Science.gov (United States)

    Ismail, A. S.; Mamat, M. H.; Malek, M. F.; Saidi, S. A.; Yusoff, M. M.; Mohamed, R.; Sin, N. D. Md; Suriani, A. B.; Rusop, M.

    2018-05-01

    Aluminum (Al)-doped zinc oxide (ZnO) nanorod array films were successfully deposited at different growth time on zinc oxide (ZnO) seed layer coated glass substrate using sol-gel immersion method. The morphology images of the films showed that the thicknesses of the films were increased parallel with the increment of growth period. The surface topology of the films displayed an increment of roughness as the growth period increased. Optical properties of the samples exposed that the percentage of transmittances reduced at higher growth time. Besides, the Urbach energy of the films slightly increased as the immersion time increased. The current-voltage (I-V) measurement indicated that the resistance increased as the immersion time increased owing to the appearance of intrinsic layer on top of the nanorods.

  20. Synthesis and photoluminescence of a full zinc blende phase ZnO nanorod array

    International Nuclear Information System (INIS)

    Zhou Shaomin; Gong Hechun; Zhang Bin; Du Zuliang; Zhang Xingtang; Wu Sixin

    2008-01-01

    A single-crystalline ZnO nanorod array with rectangular cross-sections has been synthesized, in which the as-obtained products are a complete metastable zinc blende (ZB) phase. X-ray powder diffraction, electron microscopy, and elemental maps have been used to show that the ZB-ZnO samples have a lattice constant a = 4.580 A, and are free from contamination by hexagonal wurtzite (HW) ZnO. Based on our experimental data, the associated growth mechanism is tentatively suggested. In addition, the photoluminescence (PL) spectrum (about 400 nm (3.1 eV)) of the as-fabricated ZB-ZnO products was detected; this is the first experimental report of the optical properties of ZB-ZnO nanorod arrays

  1. Immobilization of uricase on ZnO nanorods for a reagentless uric acid biosensor

    International Nuclear Information System (INIS)

    Zhang Fenfen; Wang Xiaoli; Ai Shiyun; Sun Zhengdong; Wan Qiao; Zhu Ziqiang; Xian Yuezhong; Jin Litong; Yamamoto, Katsunobu

    2004-01-01

    A reagentless uric acid (UA) biosensor based on uricase immobilized on ZnO nanorods was developed. Direct electrochemistry and thermal stability of immobilized uricase were studied. The ZnO nanorods derived electrode retained the enzyme bioactivity and could enhance the electron transfer between the enzyme and the electrode. This sensor showed a high thermal stability up to 85 deg. C and an electrocatalytic activity to the oxidation of uric acid without the presence of an electron mediator. The electrocatalytic response showed a linear dependence on the uric acid concentration ranging from 5.0 x 10 -6 to 1.0 x 10 -3 mol L -1 with a detection limit of 2.0 x 10 -6 mol L -1 at 3σ. The apparent K M app value for the uric acid sensor was estimated to be 0.238 mM, showing a high affinity

  2. Graphene-Tapered ZnO Nanorods Array as a Flexible Antireflection Layer

    Directory of Open Access Journals (Sweden)

    Taeseup Song

    2015-01-01

    Full Text Available Flexible solar cells have drawn a great deal of attention due to their various advantages including deformable and wearable characteristics. In the solar cells, the antireflection layer plays an important role in the improvement in the conversion efficiency by increasing the light transmission and suppressing the Fresnel refraction. For the successful implantation of the antireflection layer into the flexible solar cells, the flexible mechanical property of the antireflection layer is also necessary. However, the study on flexible antireflection layer for the flexible solar cells or optoelectronics is still lacking. In this study, we report the graphene-tapered ZnO nanorods array as a flexible antireflection layer for the application in flexible solar cells. Flexible two-dimensional graphene sheet and the tapered morphology of ZnO nanorods enable conformal coverage on the flexible substrate with curved surface and significant improvements in antireflection properties, respectively.

  3. A template-free sol-gel technique for controlled growth of ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Huang, N.; Zhu, M.W.; Gao, L.J.; Gong, J.; Sun, C.; Jiang, X.

    2011-01-01

    The growth of ZnO nanorod arrays via a template-free sol-gel process was investigated. The nanorod is single-crystalline wurtzite structure with [0 0 0 1] growth direction determined by the transmission electron microscope. The aligned ZnO arrays were obtained directly on the glass substrates by adjusting the temperatures and the withdrawal speeds, without seed-layer or template assistant. A thicker oriented ZnO nanorod arrays was obtained at proper experimental conditions by adding dip-coating layers. Room temperature photoluminescence spectrum exhibits an intensive UV emission with a weak broad green emission as well as a blue double-peak emission located at 451 and 468 nm, respectively. Further investigation results show that the difference in the alignment of nanorods ascribes to the different orientations of the nanoparticles-packed film formed prior to nanorods on the substrate. Well ordered ZnO nanorods are formed from this film with good c-axis orientation. Our study is expected to pave a way for direct growth of oriented nanorods by low-cost solution approaches.

  4. Diameter-dependence of the electronic structures of the ZnO nanorods

    International Nuclear Information System (INIS)

    Chiou, J.W.; Kumar, K.P.K.; Jan, J.C.; Tsai, H.M.; Bao, C.W.; Pong, W.F.; Tsai, M.-H.; Hong, I.-H.; Klauser, R.; Lee, J.F.; Wu, J.J.; Liu, S.C.

    2004-01-01

    Full text: O K-, Zn L3- and K-edges x-ray absorption near-edge structure (XANES) spectra and scanning photoelectron microscopy (SPEM) spectra were measured for the ZnO nanorods with various diameters to study their electronic structures. Analysis of the XANES spectra revealed that charge transfer from the O 2p to Zn 3d states is enhanced with the decrease of the nanorod diameter. The charge transfer due to O 2p-Zn 3d hybridization is found to be compensated by the Zn 4p to O 2p charge transfer due to O 2p-Zn 4p rehybridization in consistence with the Zn 3d SPEM results. The valence-band photoemission spectra show changes in the electronic structures, especially near to the Fermi level, with the decrease of the nanorod diameter due to surface effect and/or local electrostatic polarization

  5. A novel, substrate independent three-step process for the growth of uniform ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Byrne, D.; McGlynn, E.; Henry, M.O.; Kumar, K.; Hughes, G.

    2010-01-01

    We report a three-step deposition process for uniform arrays of ZnO nanorods, involving chemical bath deposition of aligned seed layers followed by nanorod nucleation sites and subsequent vapour phase transport growth of nanorods. This combines chemical bath deposition techniques, which enable substrate independent seeding and nucleation site generation with vapour phase transport growth of high crystalline and optical quality ZnO nanorod arrays. Our data indicate that the three-step process produces uniform nanorod arrays with narrow and rather monodisperse rod diameters (∼ 70 nm) across substrates of centimetre dimensions. X-ray photoelectron spectroscopy, scanning electron microscopy and X-ray diffraction were used to study the growth mechanism and characterise the nanostructures.

  6. Growth of thin film containing high density ZnO nanorods with low temperature calcinated seed layer

    Science.gov (United States)

    Panda, Rudrashish; Samal, Rudranarayan; Khatua, Lizina; Das, Susanta Kumar

    2018-05-01

    In this work we demonstrate the growth of thin film containing high density ZnO nanorods by using drop casting of the seed layer calcinated at a low temperature of 132 °C. Chemical bath deposition (CBD) method is used to grow the nanorods. X-ray diffraction (XRD) analysis and Field Emission Scanning Electron Microscopy (FESEM) are performed for the structural and morphological characterizations of the nanorods. The average diameter and length of nanorods are found to be 33 nm and 270 nm respectively. The bandgap of the material is estimated to be 3.2 eV from the UV-Visible absorption spectroscopy. The reported method is much more cost-effective and can be used for growth of ZnO nanorods for various applications.

  7. Effect of Zn(NO3)2 concentration in hydrothermal-electrochemical deposition on morphology and photoelectrochemical properties of ZnO nanorods

    Science.gov (United States)

    Yilmaz, Ceren; Unal, Ugur

    2016-04-01

    Zn(NO3)2 concentration had been reported to be significantly influential on electrodeposition of ZnO structures. In this work, this issue is revisited using hydrothermal-electrochemical deposition (HED). Seedless, cathodic electrochemical deposition of ZnO films is carried out on ITO electrode at 130 °C in a closed glass reactor with varying Zn(NO3)2 concentration. Regardless of the concentration of Zn2+ precursor (0.001-0.1 M) in the deposition solution, vertically aligned 1-D ZnO nanorods are obtained as opposed to electrodepositions at lower temperatures (70-80 °C). We also report the effects of high bath temperature and pressure on the photoelectrochemical properties of the ZnO films. Manipulation of precursor concentration in the deposition solution allows adjustment of the aspect ratio of the nanorods and the degree of texturation along the c-axis; hence photoinduced current density. HED is shown to provide a single step synthesis route to prepare ZnO rods with desired aspect ratio specific for the desired application just by controlling the precursor concentration.

  8. Electrochemical L-lactic acid sensor based on immobilized ZnO nanorods with lactate oxidase.

    Science.gov (United States)

    Ibupoto, Zafar Hussain; Shah, Syed Muhammad Usman Ali; Khun, Kimleang; Willander, Magnus

    2012-01-01

    In this work, fabrication of gold coated glass substrate, growth of ZnO nanorods and potentiometric response of lactic acid are explained. The biosensor was developed by immobilizing the lactate oxidase on the ZnO nanorods in combination with glutaraldehyde as a cross linker for lactate oxidase enzyme. The potentiometric technique was applied for the measuring the output (EMF) response of l-lactic acid biosensor. We noticed that the present biosensor has wide linear detection range of concentration from 1 × 10(-4)-1 × 10(0) mM with acceptable sensitivity about 41.33 ± 1.58 mV/decade. In addition, the proposed biosensor showed fast response time less than 10 s, a good selectivity towards l-lactic acid in presence of common interfering substances such as ascorbic acid, urea, glucose, galactose, magnesium ions and calcium ions. The present biosensor based on immobilized ZnO nanorods with lactate oxidase sustained its stability for more than three weeks.

  9. Electrochemical L-Lactic Acid Sensor Based on Immobilized ZnO Nanorods with Lactate Oxidase

    Directory of Open Access Journals (Sweden)

    Kimleang Khun

    2012-02-01

    Full Text Available In this work, fabrication of gold coated glass substrate, growth of ZnO nanorods and potentiometric response of lactic acid are explained. The biosensor was developed by immobilizing the lactate oxidase on the ZnO nanorods in combination with glutaraldehyde as a cross linker for lactate oxidase enzyme. The potentiometric technique was applied for the measuring the output (EMF response of L-lactic acid biosensor. We noticed that the present biosensor has wide linear detection range of concentration from 1 × 10−4–1 × 100 mM with acceptable sensitivity about 41.33 ± 1.58 mV/decade. In addition, the proposed biosensor showed fast response time less than 10 s, a good selectivity towards L-lactic acid in presence of common interfering substances such as ascorbic acid, urea, glucose, galactose, magnesium ions and calcium ions. The present biosensor based on immobilized ZnO nanorods with lactate oxidase sustained its stability for more than three weeks.

  10. SILAR controlled CdSe nanoparticles sensitized ZnO nanorods photoanode for solar cell application: Electrolyte effect.

    Science.gov (United States)

    Nikam, Pratibha R; Baviskar, Prashant K; Majumder, Sutripto; Sali, Jaydeep V; Sankapal, Babasaheb R

    2018-08-15

    Controlled growth of different sizes of cadmium selenide (CdSe) nanoparticles over well aligned ZnO nanorods have been performed using successive ionic layer adsorption and reaction (SILAR) technique at room temperature (27 °C) in order to form nano heterostructure solar cells. Deposition of compact layer of zinc oxide (ZnO) by SILAR technique on fluorine doped tin oxide (FTO) coated glass substrate followed by growth of vertically aligned ZnO nanorods array using chemical bath deposition (CBD) at low temperature (SILAR cycles for CdSe and with use of different electrolytes have been recorded as J-V characteristics and the maximum conversion efficiency of 0.63% have been attained with ferro/ferri cyanide electrolyte for 12 cycles CdSe coating over 1-D ZnO nanorods. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Synthesis and characterization of ZnO nanorod films for photocatalytic disinfection of contaminated water

    International Nuclear Information System (INIS)

    Rodriguez, Juan; Paraguay-Delgado, F.; Lopez, Alcides; Alarcon, Julio; Estrada, Walter

    2010-01-01

    The growth of ZnO nanorods on a flat substrate was studied as a function of the main parameters used in their preparation and their ability to photocatalytically eliminate bacteria in water. The seed layer was obtained, by a spray pyrolysis technique, from a zinc acetate solution. Subsequently, to grow the rods, the seeds were immersed in a basic solution of zinc nitrate maintained at 90 o C. The growth parameters, thickness of the seed layer, acidity of the precursor solution used to obtain the seed layer, and the rate of crystal growth on the seed layer during the thermal bath treatment, were studied. The resulting materials were characterized morphologically by scanning electron microscopy and transmission electron microscopy (TEM); X-ray diffraction and TEM were used to study their structure and ultraviolet-visible spectroscopy to determine their absorbance. Most of the obtained materials were textured in the (002) direction perpendicular to the substrate. The rods have a hexagonal cross section between 60 and 150 nm. Using these rods, the photocatalytic degradation of Escherichia coli bacteria in water was studied; a positive influence of the surface area and crystalline growth on the degradation rate was observed.

  12. Synthesis and characterization of ZnO nanorod films for photocatalytic disinfection of contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Juan, E-mail: rodriguezback@gmail.co [Facultad de Ciencias, Universidad Nacional de Ingenieria, P.O. Box 31-139, Av. Tupac Amaru 210, Lima (Peru); Universidad de Tarapaca, Av. General Velasquez 1775, Arica (Chile); Paraguay-Delgado, F. [Centro de Investigacion en Materiales Avanzados S. C. Miguel de Cervantes 120, Chihuahua, Chih, CP 31109 (Mexico); National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Canada T6G 2 M9 (Canada); Lopez, Alcides; Alarcon, Julio; Estrada, Walter [Facultad de Ciencias, Universidad Nacional de Ingenieria, P.O. Box 31-139, Av. Tupac Amaru 210, Lima (Peru)

    2010-11-01

    The growth of ZnO nanorods on a flat substrate was studied as a function of the main parameters used in their preparation and their ability to photocatalytically eliminate bacteria in water. The seed layer was obtained, by a spray pyrolysis technique, from a zinc acetate solution. Subsequently, to grow the rods, the seeds were immersed in a basic solution of zinc nitrate maintained at 90 {sup o}C. The growth parameters, thickness of the seed layer, acidity of the precursor solution used to obtain the seed layer, and the rate of crystal growth on the seed layer during the thermal bath treatment, were studied. The resulting materials were characterized morphologically by scanning electron microscopy and transmission electron microscopy (TEM); X-ray diffraction and TEM were used to study their structure and ultraviolet-visible spectroscopy to determine their absorbance. Most of the obtained materials were textured in the (002) direction perpendicular to the substrate. The rods have a hexagonal cross section between 60 and 150 nm. Using these rods, the photocatalytic degradation of Escherichia coli bacteria in water was studied; a positive influence of the surface area and crystalline growth on the degradation rate was observed.

  13. Synchrotron X-ray Scattering of ZnO Nanorods: Periodic Ordering and Lattice Size

    International Nuclear Information System (INIS)

    Zhu, Z.; Andelman, T.; Yin, M.; Chen, T.; Ehrlich, S.; O'Brien, S.; Osgood, Jr. R.

    2005-01-01

    We demonstrate that synchrotron x-ray powder diffraction (XRD) is a powerful technique for studying the structure and self-organization of zinc-oxide nanostructures. Zinc-oxide nanorods were prepared by a solution-growth method that resulted in uniform nanorods with 2-nm diameter and lengths in the range 10-50 nm. These nanorods were structurally characterized by a combination of small-angle and wide-angle synchrotron XRD and transmission electron microscopy (TEM). Small-angle XRD and TEM were used to investigate nanorod self-assembly and the influence of surfactant/precursor ratio on self-assembly. Wide-angle XRD was used to study the evolution of nanorod growth as a function of synthesis time and surfactant/precursor ratio

  14. Electrochemical properties of TiO{sub 2} encapsulated ZnO nanorod aggregates dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Justin Raj, C.; Karthick, S.N.; Dennyson Savariraj, A.; Hemalatha, K.V.; Park, Song-Ki; Kim, Hee-Je [Pusan National University, Department of Electrical Engineering, San 30, Jangjeong-Dong, Gumjeong-Ku, Busan 609 735 (Korea, Republic of); Prabakar, K., E-mail: prabakar@pusan.ac.kr [Pusan National University, Department of Electrical Engineering, San 30, Jangjeong-Dong, Gumjeong-Ku, Busan 609 735 (Korea, Republic of)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer ZnO nanorod aggregates were synthesized by simple co-precipitation technique. Black-Right-Pointing-Pointer TiO{sub 2} encapsulated ZnO nanorod aggregates photoanode was used for the DSSC. Black-Right-Pointing-Pointer TiO{sub 2} encapsulated ZnO nanorod aggregates shows an enhanced efficiency. Black-Right-Pointing-Pointer The electron recombination and transport properties were studied using EIS method. - Abstract: Dye sensitized solar cells based on TiO{sub 2} encapsulated ZnO nanorod (NR) aggregates were fabricated and electrochemical performance was analyzed using impedance spectroscopy as a function of forward bias voltage. Charge transfer properties such as electron life time ({tau}{sub n}), electron diffusion coefficient (D{sub n}) and electron diffusion length (L{sub n}) were calculated in order to ensure the influence of TiO{sub 2} layer over the ZnO NR aggregates. It is found that the short circuit current density (Jsc = 5.8 mA cm{sup -2}), open circuit potential (V{sub oc} = 0.743 V), fill factor (FF = 0.57) and conversion efficiency are significantly improved by the introduction of TiO{sub 2} layer over ZnO photoanode. A power conversion efficiency of about 2.48% has been achieved for TiO{sub 2}/ZnO cell, which is higher than that of bare ZnO NR aggregate based cells (1.73%). The formation of an inherent energy barrier between TiO{sub 2} and ZnO films and the passivation of surface traps on the ZnO film caused by the introduction of TiO{sub 2} layer increase the dye absorption and favor the electron transport which may be responsible for the enhanced performance of TiO{sub 2}/ZnO cell.

  15. Electrochemical properties of TiO2 encapsulated ZnO nanorod aggregates dye sensitized solar cells

    International Nuclear Information System (INIS)

    Justin Raj, C.; Karthick, S.N.; Dennyson Savariraj, A.; Hemalatha, K.V.; Park, Song-Ki; Kim, Hee-Je; Prabakar, K.

    2012-01-01

    Highlights: ► ZnO nanorod aggregates were synthesized by simple co-precipitation technique. ► TiO 2 encapsulated ZnO nanorod aggregates photoanode was used for the DSSC. ► TiO 2 encapsulated ZnO nanorod aggregates shows an enhanced efficiency. ► The electron recombination and transport properties were studied using EIS method. - Abstract: Dye sensitized solar cells based on TiO 2 encapsulated ZnO nanorod (NR) aggregates were fabricated and electrochemical performance was analyzed using impedance spectroscopy as a function of forward bias voltage. Charge transfer properties such as electron life time (τ n ), electron diffusion coefficient (D n ) and electron diffusion length (L n ) were calculated in order to ensure the influence of TiO 2 layer over the ZnO NR aggregates. It is found that the short circuit current density (Jsc = 5.8 mA cm −2 ), open circuit potential (V oc = 0.743 V), fill factor (FF = 0.57) and conversion efficiency are significantly improved by the introduction of TiO 2 layer over ZnO photoanode. A power conversion efficiency of about 2.48% has been achieved for TiO 2 /ZnO cell, which is higher than that of bare ZnO NR aggregate based cells (1.73%). The formation of an inherent energy barrier between TiO 2 and ZnO films and the passivation of surface traps on the ZnO film caused by the introduction of TiO 2 layer increase the dye absorption and favor the electron transport which may be responsible for the enhanced performance of TiO 2 /ZnO cell.

  16. Inactivation of bacterial biofilms using visible-light-activated unmodified ZnO nanorods

    Science.gov (United States)

    Aponiene, Kristina; Serevičius, Tomas; Luksiene, Zivile; Juršėnas, Saulius

    2017-09-01

    Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possesses a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation, and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible-light absorption. In this work we show that even unmodified ZnO nanorods grown by an aqueous chemical growth technique are found to possess intrinsic defects that can be activated by visible light (λ = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria. Time-resolved fluorescence analysis has revealed that visible-light excitation creates long-lived charge carriers (τ > 1 μs), which might be crucial for destructive biochemical reactions achieving significant bacterial biofilm inactivation. ZnO nanorods covered with bacterial biofilms of Enterococcus faecalis MSCL 302 after illumination by visible light (λ = 405 nm) were inactivated by 2 log, and Listeria monocytogenes ATCL3C 7644 and Escherichia coli O157:H7 biofilms by 4 log. Heterogenic waste-water microbial biofilms, consisting of a mixed population of mesophilic bacteria after illumination with visible light were also completely destroyed.

  17. Performance of natural-dye-sensitized solar cells by ZnO nanorod and nanowall enhanced photoelectrodes

    Directory of Open Access Journals (Sweden)

    Saif Saadaoui

    2017-01-01

    Full Text Available In this work, two natural dyes extracted from henna and mallow plants with a maximum absorbance at 665 nm were studied and used as sensitizers in the fabrication of dye-sensitized solar cells (DSSCs. Fourier transform infrared (FTIR spectra of the extract revealed the presence of anchoring groups and coloring constituents. Two different structures were prepared by chemical bath deposition (CBD using zinc oxide (ZnO layers to obtain ZnO nanowall (NW or nanorod (NR layers employed as a thin film at the photoanode side of the DSSC. The ZnO layers were annealed at different temperatures under various gas sources. Indeed, the forming gas (FG (N2/H2 95:5 was found to enhance the conductivity by a factor of 103 compared to nitrogen (N2 or oxygen (O2 annealing gas. The NR width varied between 40 and 100 nm and the length from 500 to 1000 nm, depending on the growth time. The obtained NWs had a length of 850 nm. The properties of the developed ZnO NW and NR layers with different thicknesses and their effect on the photovoltaic parameters were studied. An internal coverage of the ZnO NWs was also applied by the deposition of a thin TiO2 layer by reactive sputtering to improve the cell performance. The application of this layer increased the overall short circuit current Jsc by seven times from 2.45 × 10−3 mA/cm2 to 1.70 × 10−2 mA /cm2.

  18. Investigations on photoelectrochemical performance of boron doped ZnO nanorods synthesized by facile hydrothermal technique

    Science.gov (United States)

    Sharma, Akash; Chakraborty, Mohua; Thangavel, R.

    2018-05-01

    Undoped and 10% Boron (B)-doped Zinc Oxide nanorods (ZnO NRs) on Tin doped Indium Oxide (ITO) coated glass substrates were synthesized using facile sol-gel, spin coating and hydrothermal method. The impact of adding Boron on the structural, optical properties, surface morphology and photoelectrochemical (PEC) performances of the ZnO NRs have been investigated. The XRD pattern confirmed the formation of pure hexagonal phase with space group P63mc (186). The same can also be clearly observed form the FESEM images. The UV-Vis study shows the narrowing in band gap from 3.22 eV to 3.19 eV with incorporation of Boron in ZnO matrix. The B-doped ZnO NRs sample shows an enhanced photocurrent density of 1.31 mA/cm2 at 0.5 V (vs. Ag/AgCl), which is more than 171% enhancement compared to bare ZnO NRs (0.483 mA/cm2) in 0.1 M Na2SO4 aqueous solution. The results clearly indicates that the boron doped ZnO NRs can be used as an efficient photoelectrode material for photoelectrochemical cell.

  19. Arginine-assisted immobilization of silver nanoparticles on ZnO nanorods: an enhanced and reusable antibacterial substrate without human cell cytotoxicity

    Science.gov (United States)

    Agnihotri, Shekhar; Bajaj, Geetika; Mukherji, Suparna; Mukherji, Soumyo

    2015-04-01

    Silver-based hybrid nanomaterials are gaining interest as potential alternatives for conventional antimicrobial agents. Herein, we present a simple, facile and eco-friendly approach for the deposition of silver nanoparticles (AgNPs) on ZnO nanorods, which act as a nanoreactor for in situ synthesis and as an immobilizing template in the presence of arginine. The presence of arginine enhanced the stability of ZnO deposition on the glass substrate by hindering the dissolution of zinc under alkaline conditions. Various Ag/ZnO hybrid nanorod (HNR) samples were screened to obtain a high amount of silver immobilization on the ZnO substrate. Ag/ZnO HNRs displayed potent antibacterial ability and could achieve 100% kill for both Escherichia coli and Bacillus subtilis strains under various test conditions. The hybrid material mediated its dual mode of antibacterial action through direct contact-killing and release of silver ions/nanoparticles and showed superior bactericidal performance compared to pure ZnO nanorods and colloidal AgNPs. No significant decline in antibacterial efficacy was observed even after the same substrate was repeatedly reused multiple times. Interestingly, the amount of Ag and Zn release was much below their maximal limit in drinking water, thus preventing potential health hazards. Immobilized AgNPs showed no cytotoxic effects on the human hepatocarcinoma cell line (HepG2). Moreover, treating cells with the antibacterial substrate for 24 hours did not lead to significant generation of reactive oxygen species (ROS). The good biocompatibility and bactericidal efficacy would thus make it feasible to utilize this immobilization strategy for preparing new-generation antibacterial coatings.Silver-based hybrid nanomaterials are gaining interest as potential alternatives for conventional antimicrobial agents. Herein, we present a simple, facile and eco-friendly approach for the deposition of silver nanoparticles (AgNPs) on ZnO nanorods, which act as a

  20. Facile synthesis of highly branched jacks-like ZnO nanorods and their applications in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sudhagar, P. [Center for Next Generation Dye-sensitized Solar Cells, WCU Program Department of Energy Engineering, Hanyang University, Seongdong-gu, Seoul- 133 791 (Korea, Republic of); Kumar, R. Saravana [R and D Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, Tamilnadu (India); Jung, June Hyuk; Cho, Woohyung [Center for Next Generation Dye-sensitized Solar Cells, WCU Program Department of Energy Engineering, Hanyang University, Seongdong-gu, Seoul- 133 791 (Korea, Republic of); Sathyamoorthy, R. [R and D Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, Tamilnadu (India); Won, Jongok [Department of Chemistry, Sejong University, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Kang, Yong Soo, E-mail: kangys@hanyang.ac.kr [Center for Next Generation Dye-sensitized Solar Cells, WCU Program Department of Energy Engineering, Hanyang University, Seongdong-gu, Seoul- 133 791 (Korea, Republic of)

    2011-09-15

    Graphical abstract: -- Abstract: Highly branched, jacks-like ZnO nanorods architecture were explored as a photoanode in dye-sensitized solar cells, and their photovoltaic performance was compared with that of branch-free ZnO nanorods photoanodes. The highly branched network and large pores of the jacks-like ZnO nanorods electrodes enhances the charge transport, and electrolyte penetration. Thus, the jacks-like ZnO nanorods DSSCs render a higher conversion efficiency of {eta} = 1.82% (V{sub oc} = 0.59 V, J{sub sc} = 5.52 mA cm{sup -2}) than that of the branch-free ZnO nanorods electrodes ({eta} = 1.08%, V{sub oc} = 0.49 V, J{sub sc} = 4.02 mA cm{sup -2}). The incident photon-to-current conversion efficiency measurements reveal that the jacks-like ZnO nanorods DSSCs exhibit higher internal quantum efficiency ({approx}59.1%) than do the branch-free ZnO nanorods DSSC ({approx}52.5%). The charge transfer resistances at the ZnO/dye/electrolyte interfaces investigated using electrochemical impedance spectroscopy showed that the jacks-like ZnO nanorods DSSC had high charge transfer resistance and a slightly longer electron lifetime, thus improving the solar-cell performance.

  1. Facile synthesis of highly branched jacks-like ZnO nanorods and their applications in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Sudhagar, P.; Kumar, R. Saravana; Jung, June Hyuk; Cho, Woohyung; Sathyamoorthy, R.; Won, Jongok; Kang, Yong Soo

    2011-01-01

    Graphical abstract: -- Abstract: Highly branched, jacks-like ZnO nanorods architecture were explored as a photoanode in dye-sensitized solar cells, and their photovoltaic performance was compared with that of branch-free ZnO nanorods photoanodes. The highly branched network and large pores of the jacks-like ZnO nanorods electrodes enhances the charge transport, and electrolyte penetration. Thus, the jacks-like ZnO nanorods DSSCs render a higher conversion efficiency of η = 1.82% (V oc = 0.59 V, J sc = 5.52 mA cm -2 ) than that of the branch-free ZnO nanorods electrodes (η = 1.08%, V oc = 0.49 V, J sc = 4.02 mA cm -2 ). The incident photon-to-current conversion efficiency measurements reveal that the jacks-like ZnO nanorods DSSCs exhibit higher internal quantum efficiency (∼59.1%) than do the branch-free ZnO nanorods DSSC (∼52.5%). The charge transfer resistances at the ZnO/dye/electrolyte interfaces investigated using electrochemical impedance spectroscopy showed that the jacks-like ZnO nanorods DSSC had high charge transfer resistance and a slightly longer electron lifetime, thus improving the solar-cell performance.

  2. Magnetic and optical properties of Mn-doped ZnO vertically aligned nanorods synthesized by hydrothermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Panda, J.; Sasmal, I.; Nath, T. K., E-mail: tnath@phy.iitkgp.ernet.in, E-mail: tapnath@gmail.com [Department of Physics, Indian Institute Technology Kharagpur, West Bengal, 721302 (India)

    2016-03-15

    In this paper we have reported the synthesis of high quality vertically aligned undoped and Mn-doped ZnO single crystalline nanorods arrays on Si (100) substrates using two steps process, namely, initial slow seed layer formation followed by solution growth employing wet chemical hydrothermal method. The shapes of the as grown single crystalline nanorods are hexagonal. The diameter and length of the as grown undoped ZnO nanorods varies in the range of 80-150 nm and 1.0 - 1.4 μm, respectively. Along with the lattice parameters of the hexagonal crystal structure, the diameter and length of Mn doped ZnO nanorods are found to increase slightly as compared to the undoped ZnO nanorods. The X-ray photoelectron spectroscopy confirms the presence of Mn atoms in Mn{sup 2+} state in the single crystalline ZnO nanorods. The recorded photoluminescence spectrum contains two emissions peaks having UV exciton emissions along with a green-yellow emission. The green-yellow emissions provide the evidence of singly ionized oxygen vacancies. The magnetic field dependent magnetization measurements [M (H)] and zero field cooled (ZFC) and field cooled (FC) magnetization [M(T)] measurements have been carried out at different isothermal conditions in the temperature range of 5-300 K. The Mn doped ZnO nanorods clearly show room temperature ferromagnetic ordering near room temperature down to 5 K. The observed magnetization may be attributed to the long range ferromagnetic interaction between bound magnetic polarons led by singly charged oxygen vacancies.

  3. Probing interaction of Gram-positive and Gram-negative bacterial cells with ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Aanchal; Bhargava, Richa; Poddar, Pankaj, E-mail: p.poddar@ncl.res.in

    2013-04-01

    In the present work, the physiological effects of the ZnO nanorods on the Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Aerobacter aerogenes) bacterial cells have been studied. The analysis of bacterial growth curves for various concentrations of ZnO nanorods indicates that Gram positive and Gram negative bacterial cells show inhibition at concentrations of ∼ 64 and ∼ 256 μg/mL respectively. The marked difference in susceptibility towards nanorods was also validated by spread plate and disk diffusion methods. In addition, the scanning electron micrographs show a clear damage to the cells via changed morphology of the cells from rod to coccoid etc. The confocal optical microscopy images of these cells also demonstrate the reduction in live cell count in the presence of ZnO nanorods. These, results clearly indicate that the antibacterial activity of ZnO nanorods is higher towards Gram positive bacterium than Gram negative bacterium which indicates that the structure of the cell wall might play a major role in the interaction with nanostructured materials and shows high sensitivity to the particle concentration. Highlights: ► Effect of ZnO nanorods on the growth cycles of four bacterial strains. ► A relation has been established between growth rate of bacteria and concentration. ► Serious damage in the morphology of bacterial cells in the presence of ZnO nanorods. ► Microscopic studies to see the time dependent effect on bacterial cells.

  4. Synthesis of ZnO nanorods by spray pyrolysis for H{sub 2}S gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, S.D.; Patil, G.E. [Materials Research Lab., K.T.H.M. College, Nashik 422 005 (India); Kajale, D.D. [Materials Research Lab., Arts, Commerce and Science College, Nandgaon 423 106 (India); Gaikwad, V.B. [Materials Research Lab., K.T.H.M. College, Nashik 422 005 (India); Jain, G.H., E-mail: gotanjain@rediffmail.com [Materials Research Lab., K.T.H.M. College, Nashik 422 005 (India)

    2012-07-05

    Highlights: Black-Right-Pointing-Pointer Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique. Black-Right-Pointing-Pointer ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H{sub 2}S gas (100 ppm) at 50 Degree-Sign C. Black-Right-Pointing-Pointer This ZnO thin film has potential in application of room temperature H{sub 2}S gas sensing. - Abstract: Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique (SPT). The equal amount of methanol and water is used as a solvent to dissolve the AR grade Zinc acetate for precursor solution. This solution is sprayed on to the glass substrate heated at 350 Degree-Sign C. The films were characterized by ultra-violet spectroscopy (UV), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The deposition of thin films results in a layer comprising well-shaped hexagonal ZnO nanorods with diameter of 90-120 nm and length of up to 200 nm. The gas sensing properties of these films have been investigated for various interfering gases such as CO{sub 2}, CO, ethanol, NH{sub 3} and H{sub 2}S, etc. at operating temperature from 30 Degree-Sign (room temperature) to 450 Degree-Sign C. The results indicate that the ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H{sub 2}S gas (100 ppm) at 50 Degree-Sign C. The hexagonal pillar shaped ZnO nanorods can improve the sensitivity and selectivity of the sensors.

  5. Optical and structural properties of ZnO nanorods grown on graphene oxide and reduced graphene oxide film by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Alver, U., E-mail: alver@ksu.edu.tr [Department of Physics, Kahramanmaras Sutcu Imam University, K. Maras 46100 (Turkey); Zhou, W.; Belay, A.B. [Nanoscience and Technology Center, University of Central Florida, Orlando, FL 32816 (United States); Florida Solar Energy Center, Cocoa, FL 32922 (United States); Krueger, R. [Nanoscience and Technology Center, University of Central Florida, Orlando, FL 32816 (United States); Davis, K.O.; Hickman, N.S. [Nanoscience and Technology Center, University of Central Florida, Orlando, FL 32816 (United States); Florida Solar Energy Center, Cocoa, FL 32922 (United States)

    2012-01-15

    ZnO nanorods were grown on graphene oxide (GO) and reduced graphene oxide (RGO) films with seed layers by using simple hydrothermal method. The GO films were deposited by spray coating and then annealed at 400 Degree-Sign C in argon atmosphere to obtain RGO films. The optical and structural properties of the ZnO nanorods were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet-visible spectroscopy. The XRD patterns and SEM images show that without a seed layer, no ZnO nanorod deposition occurs on GO or RGO films. Transmittance of ZnO nanorods grown on RGO films was measured to be approximately 83% at 550 nm. Furthermore, while transmittance of RGO films increases with ZnO nanorod deposition, transmittance of GO decreases.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-31

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

  7. Performance of inverted polymer solar cells with randomly oriented ZnO nanorods coupled with atomic layer deposited ZnO

    International Nuclear Information System (INIS)

    Zafar, Muhammad; Yun, Ju-Young; Kim, Do-Heyoung

    2017-01-01

    Highlights: • Hydrothermally grown, randomly oriented, and low areal density ZnO nanorods have been successfully adopted as the electron transport layer in inverted organic solar cells. • The addition of atomic layer deposited ZnO on the ZnO nanorods effectively enhance the photovoltaic performances of inverted organic solar cells. • The inverted organic solar cells with 5 nm thick-ALD ZnO showed the highest power conversion efficiency of 3.08%, which is an enhancement of approximately 80% compared to the cells without the ALD ZnO layer (PCE = 1.67%). - Abstract: Nanostructuring of the electron transport layer (ETL) in organic photovoltaic cells (OPV) is of great interest because it increases the surface area of the cell and electron transport. In this work, hydrothermally grown, randomly oriented, and low areal density ZnO nanorods (NRs) have been adopted as the ETL, and the effect of adding atomic layer deposited (ALD) ZnO on the ZnO NRs on the inverted organic solar cell performance has been investigated. The fabricated inverted organic solar cell with 5-nm-thick ALD-ZnO grown on the ZnO NRs showed the highest power conversion efficiency (PCE) of 3.08%, which is an enhancement of 85% from that of the cell without ALD-ZnO (PCE = 1.67%). The ultrathin ALD-ZnO was found to act as a curing layer of the surface defects on the hydrothermally grown ZnO NRs, resulting in an improvement in photovoltaic performance.

  8. Performance of inverted polymer solar cells with randomly oriented ZnO nanorods coupled with atomic layer deposited ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, Muhammad [School of Chemical Engineering, Chonnam National University, 300 Youngbong-dong, Gwangju 500-757 (Korea, Republic of); Yun, Ju-Young [Center for Vacuum, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Daejeon 305-600 (Korea, Republic of); Kim, Do-Heyoung, E-mail: kdhh@chonnam.ac.kr [School of Chemical Engineering, Chonnam National University, 300 Youngbong-dong, Gwangju 500-757 (Korea, Republic of)

    2017-03-15

    Highlights: • Hydrothermally grown, randomly oriented, and low areal density ZnO nanorods have been successfully adopted as the electron transport layer in inverted organic solar cells. • The addition of atomic layer deposited ZnO on the ZnO nanorods effectively enhance the photovoltaic performances of inverted organic solar cells. • The inverted organic solar cells with 5 nm thick-ALD ZnO showed the highest power conversion efficiency of 3.08%, which is an enhancement of approximately 80% compared to the cells without the ALD ZnO layer (PCE = 1.67%). - Abstract: Nanostructuring of the electron transport layer (ETL) in organic photovoltaic cells (OPV) is of great interest because it increases the surface area of the cell and electron transport. In this work, hydrothermally grown, randomly oriented, and low areal density ZnO nanorods (NRs) have been adopted as the ETL, and the effect of adding atomic layer deposited (ALD) ZnO on the ZnO NRs on the inverted organic solar cell performance has been investigated. The fabricated inverted organic solar cell with 5-nm-thick ALD-ZnO grown on the ZnO NRs showed the highest power conversion efficiency (PCE) of 3.08%, which is an enhancement of 85% from that of the cell without ALD-ZnO (PCE = 1.67%). The ultrathin ALD-ZnO was found to act as a curing layer of the surface defects on the hydrothermally grown ZnO NRs, resulting in an improvement in photovoltaic performance.

  9. Cu2ZnSn(S,Se)4 from CuxSnSy nanoparticle precursors on ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Kavalakkatt, Jaison; Lin, Xianzhong; Kornhuber, Kai; Kusch, Patryk; Ennaoui, Ahmed; Reich, Stephanie; Lux-Steiner, Martha Ch.

    2013-01-01

    Solar cells with Cu 2 ZnSnS 4 absorber thin films have a potential for high energy conversion efficiencies with earth-abundant and non-toxic elements. In this work the formation of CZTSSe from Cu x SnS y nanoparticles (NPs) deposited on ZnO nanorod (NR) arrays as precursors for zinc is investigated. The NPs are prepared using a chemical route and are dispersed in toluene. The ZnO NRs are grown on fluorine doped SnO 2 coated glass substrates by electro deposition method. A series of samples are annealed at different temperatures between 300 °C and 550 °C in selenium containing argon atmosphere. To investigate the products of the reaction between the precursors the series is analyzed by means of X-ray diffraction (XRD) and Raman spectroscopy. The morphology is recorded by scanning electron microscopy (SEM) images of broken cross sections. The XRD measurements and the SEM images show the disappearing of ZnO NRs with increasing annealing temperature. Simultaneously the XRD and Raman measurements show the formation of CZTSSe. The formation of secondary phases and the optimum conditions for the preparation of CZTSSe is discussed. - Highlights: ► Cu x SnS y nanoparticles are deposited on ZnO nanorod arrays. ► Samples are annealed at different temperatures (300–550 °C) in Se/Ar-atmosphere. ► Raman spectroscopy, X-ray diffraction and electron microscopy are performed. ► ZnO disappears with increasing annealing temperature. ► With increasing temperature Cu x SnS y and ZnO form Cu 2 ZnSn(S,Se) 4

  10. Enhancement of two photon absorption with Ni doping in the dilute magnetic semiconductor ZnO crystalline nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Amit Kumar; Kumar, Yogendra; Arjunan, M.S.; Sen, Somaditya; Shirage, Parasharam M., E-mail: pmshirage@iiti.ac.in, E-mail: paras.shirage@gmail.com [Department of Physics, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India); Centre of Materials Science and Engineering, Indian Institute of Technology Indore, Simrol Campus, Khandwa Road, Indore 452020 (India); J, Aneesh; Adarsh, K. V. [Department of Physics, Indian Institute of Science Education and Research, Bhopal 462023 (India)

    2015-12-07

    In this letter, we have investigated the third-order optical nonlinearities of high-quality Ni doped ZnO nanorods crystallized in wurtzite lattice, prepared by the wet chemical method. In our experiments, we found that the two photon absorption coefficient (β) increases by as much as 14 times, i.e., 7.6 ± 0.4 to 112 ± 6 cm/GW, when the Ni doping is increased from 0% to 10%. The substantial enhancement in β is discussed in terms of the bandgap scaling and Ni doping. Furthermore, we also show that the optical bandgap measured by UV-Vis and photoluminescence spectroscopies, continuously redshift with increasing Ni doping concentration. We envision that the strong nonlinear optical properties together with their dilute magnetic effects, they form an important class of materials for potential applications in magneto-optical and integrated optical chips.

  11. Enhancement of two photon absorption with Ni doping in the dilute magnetic semiconductor ZnO crystalline nanorods

    International Nuclear Information System (INIS)

    Rana, Amit Kumar; Kumar, Yogendra; Arjunan, M.S.; Sen, Somaditya; Shirage, Parasharam M.; J, Aneesh; Adarsh, K. V.

    2015-01-01

    In this letter, we have investigated the third-order optical nonlinearities of high-quality Ni doped ZnO nanorods crystallized in wurtzite lattice, prepared by the wet chemical method. In our experiments, we found that the two photon absorption coefficient (β) increases by as much as 14 times, i.e., 7.6 ± 0.4 to 112 ± 6 cm/GW, when the Ni doping is increased from 0% to 10%. The substantial enhancement in β is discussed in terms of the bandgap scaling and Ni doping. Furthermore, we also show that the optical bandgap measured by UV-Vis and photoluminescence spectroscopies, continuously redshift with increasing Ni doping concentration. We envision that the strong nonlinear optical properties together with their dilute magnetic effects, they form an important class of materials for potential applications in magneto-optical and integrated optical chips

  12. Single fiber UV detector based on hydrothermally synthesized ZnO nanorods for wearable computing devices

    Science.gov (United States)

    Eom, Tae Hoon; Han, Jeong In

    2018-01-01

    There has been increasing interest in zinc oxide (ZnO) based ultraviolet (UV) sensing devices over the last several decades owing to their diverse range of applications. ZnO has extraordinary properties, such as a wide band gap and high exciton binding energy, which make it a beneficial material for UV sensing device. Herein, we show a ZnO UV sensing device fabricated on a cylindrical Polyethylene terephthalate (PET) monofilament. The ZnO active layer was synthesized by hydrothermal synthesis and the Cu electrodes were deposited by radio frequency (RF) magnetron sputtering. Cu thin film was deposited uniformly on a single PET fiber by rotating it inside the sputtering chamber. Various characteristics were investigated by changing the concentration of the seed solution and the growth solution. The growth of ZnO nanorods was confirmed by Field Emission Scanning Electron Microscopy (FESEM) to see the surface state and structure, followed by X-ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. Also, current-voltage (I-V) curves were obtained to measure photocurrent and conductance. Furthermore, falling response time, rising response time, and responsivity were calculated by analyzing current-time (I-t) curves.

  13. Homogeneous vertical ZnO nanorod arrays with high conductivity on an in situ Gd nanolayer

    KAUST Repository

    Flemban, Tahani H.

    2015-10-30

    We demonstrate a novel, one-step, catalyst-free method for the production of size-controlled vertical highly conductive ZnO nanorod (NR) arrays with highly desirable characteristics by pulsed laser deposition using a Gd-doped ZnO target. Our study shows that an in situ transparent and conductive Gd nanolayer (with a uniform thickness of ∼1 nm) at the interface between a lattice-matched (11-20) a-sapphire substrate and ZnO is formed during the deposition. This nanolayer significantly induces a relaxation mechanism that controls the dislocation distribution along the growth direction; which consequently improves the formation of homogeneous vertically aligned ZnO NRs. We demonstrate that both the lattice orientation of the substrate and the Gd characteristics are important in enhancing the NR synthesis, and we report precise control of the NR density by changing the oxygen partial pressure. We show that these NRs possess high optical and electrical quality, with a mobility of 177 cm2 (V s)-1, which is comparable to the best-reported mobility of ZnO NRs. Therefore, this new and simple method has significant potential for improving the performance of materials used in a wide range of electronic and optoelectronic applications.

  14. Enhanced piezoelectric output voltage and Ohmic behavior in Cr-doped ZnO nanorods

    International Nuclear Information System (INIS)

    Sinha, Nidhi; Ray, Geeta; Godara, Sanjay; Gupta, Manoj K.; Kumar, Binay

    2014-01-01

    Highlights: • Low cost highly crystalline Cr-doped ZnO nanorods were synthesized. • Enhancement in dielectric, piezoelectric and ferroelectric properties were observed. • A high output voltage was obtained in AFM. • Cr-doping resulted in enhanced conductivity and better Ohmic behavior in ZnO/Ag contact. - Abstract: Highly crystalline Cr-doped ZnO nanorods (NRs) were synthesized by solution technique. The size distribution was analyzed by high resolution tunneling electron microscope (HRTEM) and particle size analyzer. In atomic force microscope (AFM) studies, peak to peak 8 mV output voltage was obtained on the application of constant normal force of 25 nN. It showed high dielectric constant (980) with phase transition at 69 °C. Polarization vs. electric field (P–E) loops with remnant polarization (6.18 μC/cm 2 ) and coercive field (0.96 kV/cm) were obtained. In I–V studies, Cr-doping was found to reduce the rectifying behavior in the Ag/ZnO Schottky contact which is useful for field effect transistor (FET) and solar cell applications. With these excellent properties, Cr-doped ZnO NRs can be used in nanopiezoelectronics, charge storage and ferroelectric applications

  15. Synthesis and Characterization of Mg-doped ZnO Nanorods for Biomedical Applications

    Science.gov (United States)

    Gemar, H.; Das, N. C.; Wanekaya, A.; Delong, R.; Ghosh, K.

    2013-03-01

    Nanomaterials research has become a major attraction in the field of advanced materials research in the area of Physics, Chemistry, and Materials Science. Bio-compatible and chemically stable metal nanoparticles have biomedical applications that includes drug delivery, cell and DNA separation, gene cloning, magnetic resonance imaging (MRI). This research is aimed at the fabrication and characterization of Mg-doped ZnO nanorods. Hydrothermal synthesis of undoped ZnO and Mg-doped ZnO nanorods is carried out using aqueous solutions of Zn(NO3)2 .6H2O, MgSO4, and using NH4OH as hydrolytic catalyst. Nanomaterials of different sizes and shapes were synthesized by varying the process parameters such as molarity (0.15M, 0.3M, 0.5M) and pH (8-11) of the precursors, growth temperature (130°C), and annealing time during the hydrothermal Process. Structural, morphological, and optical properties are studied using various techniques such as XRD, SEM, UV-vis and PL spectroscopy. Detailed structural, and optical properties will be discussed in this presentation. This work is partially supported by National Cancer Institute (1 R15 CA139390-01).

  16. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    Energy Technology Data Exchange (ETDEWEB)

    Zirak, M. [Department of Physics, Sharif University of Technology, P.O. Box 11555-9161, Tehran (Iran, Islamic Republic of); Moradlou, O. [Department of Chemistry, Faculty of Sciences, Alzahra University, P.O. Box 1993893973, Tehran (Iran, Islamic Republic of); Bayati, M.R. [Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695-7907 (United States); Nien, Y.T. [Department of Materials Science and Engineering, National Formosa University, Huwei District, Taiwan (China); Moshfegh, A.Z., E-mail: moshfegh@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11555-9161, Tehran (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-8969, Tehran (Iran, Islamic Republic of)

    2013-05-15

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core–shell nanorods where the features were grown through a multistep procedure including sol–gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV–vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min{sup −1} under UV illumination and 0.007 min{sup −1} under visible light. The difference in catalytic activities of the ZnO@CdS core–shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core–shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  17. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    Science.gov (United States)

    Zirak, M.; Moradlou, O.; Bayati, M. R.; Nien, Y. T.; Moshfegh, A. Z.

    2013-05-01

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core-shell nanorods where the features were grown through a multistep procedure including sol-gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV-vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min-1 under UV illumination and 0.007 min-1 under visible light. The difference in catalytic activities of the ZnO@CdS core-shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core-shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  18. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    International Nuclear Information System (INIS)

    Zirak, M.; Moradlou, O.; Bayati, M.R.; Nien, Y.T.; Moshfegh, A.Z.

    2013-01-01

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core–shell nanorods where the features were grown through a multistep procedure including sol–gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV–vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min −1 under UV illumination and 0.007 min −1 under visible light. The difference in catalytic activities of the ZnO@CdS core–shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core–shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

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

    International Nuclear Information System (INIS)

    Dwivedi, Charu; Dutta, V

    2012-01-01

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

  20. Ag nanoparticles-decorated ZnO nanorod array on a mechanical flexible substrate with enhanced optical and antimicrobial properties

    OpenAIRE

    Chen, Yi; Tse, Wai Hei; Chen, Longyan; Zhang, Jin

    2015-01-01

    Heteronanostructured zinc oxide nanorod (ZnO NR) array are vertically grown on polydimethylsiloxane (PDMS) through a hydrothermal method followed by an in situ deposition of silver nanoparticles (Ag NPs) through a photoreduction process. The Ag-ZnO heterostructured nanorods on PDMS are measured with an average diameter of 160?nm and an average length of 2??m. ZnO NRs measured by high-resolution transmission electron microscope (HRTEM) shows highly crystalline with a lattice fringe of 0.255?nm...

  1. Tunable light extraction efficiency of GaN light emitting diodes by ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Chao, C H; Lin, W H; Lin, C F; Chen, C H; Changjean, C H

    2009-01-01

    We report the influence of ZnO nanorod arrays (NRAs) on the light extraction efficiency of GaN light emitting diodes (LEDs). Our investigation indicates that the output light intensity of the device exhibits a periodic oscillation as a function of the rod length. The variation of light extraction efficiency is caused by the Fabry–Perot resonance of the film composed of the nanorods. The theoretical analysis shows a good agreement with the measurement results. Our study reveals a method to control the output light extraction efficiency of GaN LEDs via a simple solution-based synthesized ZnO NRAs

  2. Photoluminescence of Hexagonal ZnO Nanorods Hydrothermally Grown on Zn Foils in KOH Solutions with Different Values of Basicity

    Directory of Open Access Journals (Sweden)

    Nuengruethai Ekthammathat

    2013-01-01

    Full Text Available Aligned hexagonal ZnO nanorods on pure Zn foils were hydrothermally synthesized in 30 mL solutions containing 0.05–0.50 g KOH. The products were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and photoluminescence (PL spectroscopy. In this research, wurtzite hexagonal ZnO nanorods grown along the [002] direction with green light emission at 541 nm caused by singly ionized oxygen vacancies inside were detected.

  3. Nonenzymetic glucose sensing using carbon functionalized carbon doped ZnO nanorod arrays

    Science.gov (United States)

    Chakraborty, Pinak; Majumder, Tanmoy; Dhar, Saurab; Mondal, Suvra Prakash

    2018-04-01

    Fabrication of highly sensitive, long stability and low cost glucose sensors are attractive for biomedical applications and food industries. Most of the commercial glucose sensors are based on enzymatic detection which suffers from problems underlying in enzyme activities. Development of high sensitive, enzyme free sensors is a great challenge for next generation glucose sensing applications. In our study Zinc oxide nanorod sensing electrodes have been grown using low cost hydrothermal route and their nonenzymatic glucose sensing properties have been demonstrated with carbon functionalized, carbon doped ZnO nanorods (C-ZnO NRs) in neutral medium (0.1M PBS, pH 7.4) using cyclic voltammetry and amperometry measurements. The C-ZnO NRs electrodes demonstrated glucose sensitivity˜ 13.66 µAmM-1cm-2 in the concentration range 0.7 - 14 mM.

  4. ZnO Nanorods with Tunable Aspect Ratios Deriving from Oriented-attachment for Enhanced Performance in Quantum-dot Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Wu, Dapeng; Wang, Xiaolu; Cao, Kun; An, Yipeng; Song, Xiaohui; Liu, Ning; Xu, Fang; Gao, Zhiyong; Jiang, Kai

    2017-01-01

    ZnO nanorods consisted of oriented aligned elongated-nanoparticles along the [0001] direction were readily prepared with tunable aspect ratios by a facile solvothermal method. An oriented-attachment growth mechanism was proposed based on time-dependent trails and first principle density function theory calculation. Control experiments indicated that the reaction medium played important roles to influence the oriented-attachment process and the aspect ratio could be tuned from ∼4.6 to ∼16.0 by simply altering the precursor dosages. The as-prepared ZnO nanorods were applied as photoanode materials in quantum-dot sensitized solar cells. The large pore size in the film structure and rough surface of the nanorod could enhance the quantum dots loading amounts and light scattering effect. In addition, the orderly aligned primary ENPs minimized the grain boundaries for suppressed recombination and provided a direct pathway for increased electron diffusion length. Meanwhile, the enhanced film hydrophilicity facilitated the electrolyte penetration and the regeneration of oxidized sensitizers. Therefore, a high power conversion efficiency of ∼4.83% was demonstrated, indicating substantial improvement compared with that of traditional nanoparticle based device (∼3.54%).

  5. A Simple Method for the Preparation of ZnO Prickly Spheres

    Institute of Scientific and Technical Information of China (English)

    Da Zhi LI; Xin Yu SONG; Si Xiu SUN; Jin Xin GUO

    2004-01-01

    The synthesis of ZnO prickly spheres using precipitation followed by heating treatment was investigated. Zn(OH)2 precursor was prepared by precipitation process using Zn(CH3COO)2·2H2O in mixed 1-propanol-water solvent. Sodium dodecyl sulfate (SDS) as the anionic surfactant was added to control the morphology. The size and structure of ZnO prickly spheres were studied using XRD, TEM and SEM. The results showed that the morphologies and size of the spheres strongly depended on the volume ratio of 1-propanol /water and molar ratio of SDS/Zn2+. ZnO prickly spheres composed of nanorods could be obtained, when the volume ratio of 1-propanol/water = 2:3 and the molar ratio of Zn2+/SDS ≈ 450:1.

  6. Preparation of single-crystal copper ferrite nanorods and nanodisks

    International Nuclear Information System (INIS)

    Du Jimin; Liu Zhimin; Wu Weize; Li Zhonghao; Han Buxing; Huang Ying

    2005-01-01

    This article, for the first time, reports the preparation of single-crystal copper ferrite nanorods and nanodisks. Using amorphous copper ferrite nanoparticles synthesized by reverse micelle as reaction precursor, single-crystal copper ferrite nanorods were synthesized via hydrothermal method in the presence of surfactant polyethylene glycol (PEG), however, copper ferrite nanodisks were prepared through the same procedures except the surfactant PEG. The resulting nanomaterials have been characterized by powder X-ray diffraction (XRD), selected electron area diffraction (SEAD), and transmission electron microscopy (TEM). The bulk composition of the samples was determined by means of X-ray photoelectron spectroscopy (XPS)

  7. Fabrication and Characterization of Vertically Aligned ZnO Nanorod Arrays via Inverted Monolayer Colloidal Crystals Mask

    Science.gov (United States)

    Chen, Cheng; Ding, Taotao; Qi, Zhiqiang; Zhang, Wei; Zhang, Jun; Xu, Juan; Chen, Jingwen; Dai, Jiangnan; Chen, Changqing

    2018-04-01

    The periodically ordered ZnO nanorod (NR) arrays have been successfully synthesized via a hydrothermal approach on the silicon substrates by templating of the TiO2 ring deriving from the polystyrene (PS) nanosphere monolayer colloidal crystals (MCC). With the inverted MCC mask, sol-gel-derived ZnO seeds could serve as the periodic nucleation positions for the site-specific growth of ZnO NRs. The large-scale patterned arrays of single ZnO NR with good side-orientation can be readily produced. According to the experimental results, the as-integrated ZnO NR arrays showed an excellent crystal quality and optical property, very suitable for optoelectronic applications such as stimulated emitters and ZnO photonic crystal devices.

  8. Random laser based on Rhodamine 6G (Rh6G doped poly(methyl methacrylate (PMMA films coating on ZnO nanorods synthesized by hydrothermal oxidation

    Directory of Open Access Journals (Sweden)

    Hua Zhang

    Full Text Available Random laser based on Rh6G doped PMMA thin films coating on ZnO nanorods synthesized by a simple hydrothermal oxidation method has been demonstrated. This kind of random laser medium is based on waveguide structure consisting of ZnO nanorods, Rh6G doped PMMA film and air. By controlling the time of hydrothermal oxidation reaction, wheat-like and hexagonal prism ZnO nanorods have been successfully fabricated. The emission spectra of these gain mediums based on different ZnO nanorods are different. The one based on wheat-like ZnO nanorods mainly exhibits amplified spontaneous emission, and the other one based on hexagonal prism ZnO nanorods shows random laser emission. The threshold of the random laser medium is about 73.8 μJ/pulse, and the full width at half maximum (FWHM is around 2.1 nm. The emission spectra measured at different detecting angles reveal that the output direction is strongly confined in ±30° by the waveguide effect. Our experiments demonstrate a promising method to achieve organic random laser medium. Keywords: Random laser, ZnO nanorods, Hydrothermal oxidation, Rhodamine 6G (Rh6G, Poly(methyl methacrylate (PMMA

  9. Amorphous Pd-assisted H 2 detection of ZnO nanorod gas sensor with enhanced sensitivity and stability

    KAUST Repository

    Kim, Hyeonghun

    2018-02-05

    For monitoring H2 concentrations in air, diverse resistive gas sensors have been demonstrated. In particular, Pd-decorated metal oxides have shown remarkable selectivity and sensing response for H2 detection. In this work, H2 sensing behavior of amorphous Pd layer covering ZnO nanorods (am-Pd/ZnO NRs) is investigated. This is the first report on the enhanced gas sensing performance attained by using an amorphous metal layer. The amorphous Pd layer is generated by reduction reaction with a strong reducing agent (NaBH4), and it covers the ZnO nanorods completely with a thickness of 2 ∼ 5 nm. For comparison, crystalline Pd nanoparticles-decorated ZnO nanorods (c-Pd/ZnO NRs) are produced using a milder reducing agent like hydrazine. Comparing the c-Pd/ZnO NRs sensor and other previously reported hydrogen sensors based on the crystalline Pd and metal oxides, the am-Pd/ZnO NRs sensor exhibits a remarkable sensing response (12,400% at 2% H2). The enhancement is attributed to complete cover of the amorphous Pd layer on the ZnO NRs, inducing larger interfaces between the Pd and ZnO. In addition, the amorphous Pd layer prevents surface contamination of the ZnO NRs. Therefore, the am-Pd/ZnO NRs sensor maintains initial sensing performance even after 5 months.

  10. Amorphous Pd-assisted H 2 detection of ZnO nanorod gas sensor with enhanced sensitivity and stability

    KAUST Repository

    Kim, Hyeonghun; Pak, Yusin; Jeong, Yeonggyo; Kim, Woochul; Kim, Jeongnam; Jung, Gun Young

    2018-01-01

    For monitoring H2 concentrations in air, diverse resistive gas sensors have been demonstrated. In particular, Pd-decorated metal oxides have shown remarkable selectivity and sensing response for H2 detection. In this work, H2 sensing behavior of amorphous Pd layer covering ZnO nanorods (am-Pd/ZnO NRs) is investigated. This is the first report on the enhanced gas sensing performance attained by using an amorphous metal layer. The amorphous Pd layer is generated by reduction reaction with a strong reducing agent (NaBH4), and it covers the ZnO nanorods completely with a thickness of 2 ∼ 5 nm. For comparison, crystalline Pd nanoparticles-decorated ZnO nanorods (c-Pd/ZnO NRs) are produced using a milder reducing agent like hydrazine. Comparing the c-Pd/ZnO NRs sensor and other previously reported hydrogen sensors based on the crystalline Pd and metal oxides, the am-Pd/ZnO NRs sensor exhibits a remarkable sensing response (12,400% at 2% H2). The enhancement is attributed to complete cover of the amorphous Pd layer on the ZnO NRs, inducing larger interfaces between the Pd and ZnO. In addition, the amorphous Pd layer prevents surface contamination of the ZnO NRs. Therefore, the am-Pd/ZnO NRs sensor maintains initial sensing performance even after 5 months.

  11. Hydrothermal growth and characterization of vertically well-aligned and dense ZnO nanorods on glass and silicon using a simple optimizer system

    Energy Technology Data Exchange (ETDEWEB)

    Mohammad, Sabah M., E-mail: Sabahaskari14@gmail.com; Ahmed, Naser M.; Abd-Alghafour, Nabeel M. [Institute of Nano-Optoelectronics Research and Technology Laboratory (INOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Hassan, Z., E-mail: zai@usm.my [Institute of Nano-Optoelectronics Research and Technology Laboratory (INOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); CRI Natural Sciences, Universiti Sains Malaysia, Penang 11800 (Malaysia); Talib, Rawnaq A. [Institute of Nano-Optoelectronics Research and Technology Laboratory (INOR), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Polymer Research Center, University of Basra (Iraq); Omar, A. F. [School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia)

    2016-07-06

    Vertically, well-aligned and high density ZnO nanorods were successfully hydrothermally grown on glass and silicon substrates using a simple and low cost system. The mechanism of synthesis of ZnO nanorods, generated with our system under hydrothermal conditions, is investigated in this report. Field-emission scanning electron microscopy indicated that the fabricated ZnO nanorods on both substrates have hexagonal shape with diameters ranging from 20 nm to 70 nm which grew vertically from the substrate. XRD analysis confirms the formation of wurtzite ZnO phase with a preferred orientation along (002) direction perpendicular on the substrate and enhanced crystallinity. The low value of the tensile strain (0.126 %) revealed that ZnO nanorods preferred to grow along the c-axis for both substrates. Photoluminescence spectra exhibited a strong, sharp UV near band edge emission peak with narrow FWHM values for both samples.

  12. Hydrothermal growth and characterization of vertically well-aligned and dense ZnO nanorods on glass and silicon using a simple optimizer system

    International Nuclear Information System (INIS)

    Mohammad, Sabah M.; Ahmed, Naser M.; Abd-Alghafour, Nabeel M.; Hassan, Z.; Talib, Rawnaq A.; Omar, A. F.

    2016-01-01

    Vertically, well-aligned and high density ZnO nanorods were successfully hydrothermally grown on glass and silicon substrates using a simple and low cost system. The mechanism of synthesis of ZnO nanorods, generated with our system under hydrothermal conditions, is investigated in this report. Field-emission scanning electron microscopy indicated that the fabricated ZnO nanorods on both substrates have hexagonal shape with diameters ranging from 20 nm to 70 nm which grew vertically from the substrate. XRD analysis confirms the formation of wurtzite ZnO phase with a preferred orientation along (002) direction perpendicular on the substrate and enhanced crystallinity. The low value of the tensile strain (0.126 %) revealed that ZnO nanorods preferred to grow along the c-axis for both substrates. Photoluminescence spectra exhibited a strong, sharp UV near band edge emission peak with narrow FWHM values for both samples.

  13. Growth of hybrid carbon nanostructures on iron-decorated ZnO nanorods

    Science.gov (United States)

    Mbuyisa, Puleng N.; Rigoni, Federica; Sangaletti, Luigi; Ponzoni, Stefano; Pagliara, Stefania; Goldoni, Andrea; Ndwandwe, Muzi; Cepek, Cinzia

    2016-04-01

    A novel carbon-based nanostructured material, which includes carbon nanotubes (CNTs), porous carbon, nanostructured ZnO and Fe nanoparticles, has been synthetized using catalytic chemical vapour deposition (CVD) of acetylene on vertically aligned ZnO nanorods (NRs). The deposition of Fe before the CVD process induces the presence of dense CNTs in addition to the variety of nanostructures already observed on the process done on the bare NRs, which range from amorphous graphitic carbon up to nanostructured dendritic carbon films, where the NRs are partially or completely etched. The combination of scanning electron microscopy and in situ photoemission spectroscopy indicate that Fe enhances the ZnO etching, and that the CNT synthesis is favoured by the reduced Fe mobility due to the strong interaction between Fe and the NRs, and to the presence of many defects, formed during the CVD process. Our results demonstrate that the resulting new hybrid shows a higher sensitivity to ammonia gas at ambient conditions (∼60 ppb) than the carbon nanostructures obtained without the aid of Fe, the bare ZnO NRs, or other one-dimensional carbon nanostructures, making this system of potential interest for environmental ammonia monitoring. Finally, in view of the possible application in nanoscale optoelectronics, the photoexcited carrier behaviour in these hybrid systems has been characterized by time-resolved reflectivity measurements.

  14. Synthesis of 1-D ZnO nanorods and polypyrrole/1-D ZnO

    Indian Academy of Sciences (India)

    nanoparticles, nanowires, nanorods, etc., has gained increas- ing research ... method with zinc sulphate and sodium hydroxide as starting materials ... also available for detecting ammonia gas. They are: Figaro ... 2.4 Characterization. Degradation .... The temper- ature was tuned by means of varying current through heater.

  15. Preparation and spectroscopic analysis of zinc oxide nanorod thin films of different thicknesses

    Directory of Open Access Journals (Sweden)

    Mia Nasrul Haque

    2017-10-01

    Full Text Available Zinc oxide thin films with different thicknesses were prepared on microscopic glass slides by sol-gel spin coating method, then hydrothermal process was applied to produce zinc oxide nanorod arrays. The nanorod thin films were characterized by various spectroscopic methods of analysis. From the images of field emission scanning electron microscope (FESEM, it was observed that for the film thickness up to 200 nm the formed nanorods with wurtzite hexagonal structure were uniformly distributed over the entire surface substrate. From X-ray diffraction analysis it was revealed that the thin films had good polycrystalline nature with highly preferred c-axis orientation along (0 0 2 plane. The optical characterization done by UV-Vis spectrometer showed that all the films had high transparency of 83 % to 96 % in the visible region and sharp cut off at ultraviolet region of electromagnetic spectrum. The band gap of the films decreased as their thickness increased. Energy dispersive X-ray spectroscopy (EDS showed the presence of zinc and oxygen elements in the films and Fourier transform infrared spectroscopy (FT-IR revealed the chemical composition of ZnO in the film.

  16. ZnO Nanorods Based Enzymatic Biosensor for Selective Determination of Penicillin

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2011-10-01

    Full Text Available In this study, we have successfully demonstrated the fabrication of a biosensor based on well aligned single-crystal zinc oxide (ZnO nanorods which were grown on gold coated glass substrate using a low temperature aqueous chemical growth (ACG method. The ZnO nanorods were immobilized with penicillinase enzyme using the physical adsorption approach in combination with N-5-azido-2-nitrobenzoyloxysuccinimide (ANB-NOS as cross linking molecules. The potentiometric response of the sensor configuration revealed good linearity over a large logarithmic concentration range from 100 µM to 100 mM. During the investigations, the proposed sensor showed a good stability with high sensitivity of ~121 mV/decade for sensing of penicillin. A quick electrochemical response of less than 5 s with a good selectivity, repeatability, reproducibility and a negligible response to common interferents such as Na1+, K1+, d-glucose, l-glucose, ascorbic acid, uric acid, urea, sucrose, lactose, glycine, penicilloic acid and cephalosporins, was observed.

  17. ZnO Nanorods Based Enzymatic Biosensor for Selective Determination of Penicillin.

    Science.gov (United States)

    Ibupoto, Zafar Hussain; Ali, Syed Muhammad Usman; Khun, Kimleang; Chey, Chan Oeurn; Nur, Omer; Willander, Magnus

    2011-10-27

    In this study, we have successfully demonstrated the fabrication of a biosensor based on well aligned single-crystal zinc oxide (ZnO) nanorods which were grown on gold coated glass substrate using a low temperature aqueous chemical growth (ACG) method. The ZnO nanorods were immobilized with penicillinase enzyme using the physical adsorption approach in combination with N-5-azido-2-nitrobenzoyloxysuccinimide (ANB-NOS) as cross linking molecules. The potentiometric response of the sensor configuration revealed good linearity over a large logarithmic concentration range from 100 µM to 100 mM. During the investigations, the proposed sensor showed a good stability with high sensitivity of ~121 mV/decade for sensing of penicillin. A quick electrochemical response of less than 5 s with a good selectivity, repeatability, reproducibility and a negligible response to common interferents such as Na1+, K1+, d-glucose, l-glucose, ascorbic acid, uric acid, urea, sucrose, lactose, glycine, penicilloic acid and cephalosporins, was observed.

  18. Highly sensitive hydrogen detection of catalyst-free ZnO nanorod networks suspended by lithography-assisted growth

    International Nuclear Information System (INIS)

    Huh, Junghwan; Kim, Gyu Tae; Park, Jonghyurk; Park, Jeong Young

    2011-01-01

    We have successfully demonstrated a ZnO nanorod-based 3D nanostructure to show a high sensitivity and very fast response/recovery to hydrogen gas. ZnO nanorods have been synthesized selectively over the pre-defined area at relatively low temperature using a simple self-catalytic solution process assisted by a lithographic method. The conductance of the ZnO nanorod device varies significantly as the concentration of the hydrogen is changed without any additive metal catalyst, revealing a high sensitivity to hydrogen gas. Its superior performance can be explained by the porous structure of its three-dimensional network and the enhanced surface reaction of the hydrogen molecules with the oxygen defects resulting from a high surface-to-volume ratio. It was found that the change of conductance follows a power law depending on the hydrogen concentration. A Langmuir isotherm following an ideal power law and a cross-over behavior of the activation energy with respect to hydrogen concentration were observed. This is a very novel and intriguing phenomenon on nanostructured materials, which suggests competitive surface reactions in ZnO nanorod gas sensors.

  19. Highly sensitive hydrogen detection of catalyst-free ZnO nanorod networks suspended by lithography-assisted growth.

    Science.gov (United States)

    Huh, Junghwan; Park, Jonghyurk; Kim, Gyu Tae; Park, Jeong Young

    2011-02-25

    We have successfully demonstrated a ZnO nanorod-based 3D nanostructure to show a high sensitivity and very fast response/recovery to hydrogen gas. ZnO nanorods have been synthesized selectively over the pre-defined area at relatively low temperature using a simple self-catalytic solution process assisted by a lithographic method. The conductance of the ZnO nanorod device varies significantly as the concentration of the hydrogen is changed without any additive metal catalyst, revealing a high sensitivity to hydrogen gas. Its superior performance can be explained by the porous structure of its three-dimensional network and the enhanced surface reaction of the hydrogen molecules with the oxygen defects resulting from a high surface-to-volume ratio. It was found that the change of conductance follows a power law depending on the hydrogen concentration. A Langmuir isotherm following an ideal power law and a cross-over behavior of the activation energy with respect to hydrogen concentration were observed. This is a very novel and intriguing phenomenon on nanostructured materials, which suggests competitive surface reactions in ZnO nanorod gas sensors.

  20. Iron (III Ion Sensor Based on the Seedless Grown ZnO Nanorods in 3 Dimensions Using Nickel Foam Substrate

    Directory of Open Access Journals (Sweden)

    Mazhar Ali Abbasi

    2013-01-01

    Full Text Available In the present work, the seedless, highly aligned and vertical ZnO nanorods in 3 dimensions (3D were grown on the nickel foam substrate. The seedless grown ZnO nanorods were characterised by field emission scanning electron microscopy (FESEM, high resolution transmission electron microscopy (HRTEM, and X-ray diffraction (XRD techniques. The characterised seedless ZnO nanorods in 3D on nickel foam were highly dense, perpendicular to substrate, grown along the (002 crystal plane, and also composed of single crystal. In addition to this, these seedless ZnO nanorods were functionalized with trans-dinitro-dibenzo-18-6 crown ether, a selective iron (III ion ionophore, along with other components of membrane composition such as polyvinyl chloride (PVC, 2-nitopentylphenyl ether as plasticizer (NPPE, and tetrabutyl ammonium tetraphenylborate (TBATPB as conductivity increaser. The sensor electrode has shown high linearity with a wide range of detection of iron (III ion concentrations from 0.005 mM to 100 mM. The low limit of detection of the proposed ion selective electrode was found to be 0.001 mM. The proposed sensor also described high storage stability, selectivity, reproducibility, and repeatability and a quick response time of less than 10 s.

  1. A versatile light-switchable nanorod memory: Wurtzite ZnO on perovskite SrTiO3

    KAUST Repository

    Kumar, Anup Bera; Peng, Haiyang; Lourembam, James; Shen, Youde; Sun, Xiaowei; Wu, Tao

    2013-01-01

    heterojunction memory made of wurtzite ZnO nanorods grown on perovskite Nb-doped SrTiO3 (NSTO) is reported, the electronic properties of which can be drastically reconfigured by applying a voltage and light. Despite of the distinct lattice structures of Zn

  2. A patterned ZnO nanorod array/gas sensor fabricated by mechanoelectrospinning-assisted selective growth.

    Science.gov (United States)

    Wang, Xiaomei; Sun, Fazhe; Huang, Yongan; Duan, Yongqing; Yin, Zhouping

    2015-02-21

    Micropatterned ZnO nanorod arrays were fabricated by the mechanoelectrospinning-assisted direct-writing process and the hydrothermal growth process, and utilized as gas sensors that exhibited excellent Ohmic behavior and sensitivity response to oxidizing gas NO2 at low concentrations (1-100 ppm).

  3. Al-doped ZnO seed layer-dependent crystallographic control of ZnO nanorods by using electrochemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hyo-Soo; Choi, Nak-Jung [Department of Nano-Optical Engineering, Korea Polytechnic University, Siheung 429-793 (Korea, Republic of); Kim, Kyoung-Bo [Department of Metallurgical and Materials Engineering, Inha Technical College, Incheon 402-752 (Korea, Republic of); Kim, Moojin [Department of Renewable Energy, Jungwon University, Goesan-gun, Chungbuk 367-805 (Korea, Republic of); Lee, Sung-Nam, E-mail: snlee@kpu.ac.kr [Department of Nano-Optical Engineering, Korea Polytechnic University, Siheung 429-793 (Korea, Republic of)

    2016-10-15

    Highlights: • Polar and semipolar ZnO NRs were successfully achieved by hydrothermal synthesis. • Semipolar and polar ZnO NRs were grown on ZnO and AZO/m-sapphire, respectively. • Al % of AZO/m-sapphire enhanced the lateral growth rate of polar ZnO NRs. - Abstract: We investigated the effect of an Al-doped ZnO film on the crystallographic direction of ZnO nanorods (NRs) using electrochemical deposition. From high-solution X-ray diffraction measurements, the crystallographic plane of ZnO NRs grown on (1 0 0) ZnO/m-plane sapphire was (1 0 1). The surface grain size of the (100) Al-doped ZnO (AZO) film decreased with increasing Al content in the ZnO seed layer, implying that the Al dopant accelerated the three-dimensional (3D) growth of the AZO film. In addition, it was found that with increasing Al doping concentration of the AZO seed layer, the crystal orientation of the ZnO NRs grown on the AZO seed layer changed from [1 0 1] to [0 0 1]. With increasing Al content of the nonpolar (1 0 0) AZO seed layer, the small surface grains with a few crystallographic planes of the AZO film changed from semipolar (1 0 1) ZnO NRs to polar (0 0 1) ZnO NRs due to the increase of the vertical [0 0 1] growth rate of the ZnO NRs owing to excellent electrical properties.

  4. Effects of annealing on the recombination dynamics of low-temperature grown ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Hilker, B.; Bekeny, C.; Voss, T.; Gutowski, J. [IFP, Universitaet Bremen, 28334 Bremen (Germany); Hauschild, R.; Kalt, H. [Universitaet Karlsruhe, 76128 Karlsruhe (Germany); Postels, B.; Bakin, Andrey; Waag, A. [IHT, TU Braunschweig, 38023 Braunschweig (Germany)

    2007-07-01

    We present systematic temperature and excitation density dependent time-resolved photoluminescence (TRPL) measurements of as-grown and annealed ZnO nanorods fabricated by an aqueous chemical growth (ACG) technique at {proportional_to}90 C. The as-grown nanorods show strong nearband-edge and rather weak deep-level emission indicating their already good optical quality. At 4K, we find a broad emission line at 3.36 eV (line width 30 meV) which we attribute to recombination from a donor band formed through the high donor concentration. After annealing in oxygen and nitrogen atmospheres at 600-800 C well-resolved and sharper excitonic transitions are observed. To understand the recombination dynamics in the nanorods we carried out TRPL measurements using a frequency-doubled femtosecond laser and a streak camera. The as-grown sample shows a very fast monoexponential decay time of {proportional_to}10ps independent of temperature and excitation density. In contrast, the annealed samples exhibit a biexponential decay. Each a fast {tau}1 and a slow {tau}2 time constant have been determined for all annealed samples both of them significantly varying depending on the annealing atmosphere and temperature. This will be discussed on the basis of a phenomenological rate-equation model.

  5. Ultra-Fast Microwave Synthesis of ZnO Nanorods on Cellulose Substrates for UV Sensor Applications

    Directory of Open Access Journals (Sweden)

    Ana Pimentel

    2017-11-01

    Full Text Available In the present work, tracing and Whatman papers were used as substrates to grow zinc oxide (ZnO nanostructures. Cellulose-based substrates are cost-efficient, highly sensitive and environmentally friendly. ZnO nanostructures with hexagonal structure were synthesized by hydrothermal under microwave irradiation using an ultrafast approach, that is, a fixed synthesis time of 10 min. The effect of synthesis temperature on ZnO nanostructures was investigated from 70 to 130 °C. An Ultra Violet (UV/Ozone treatment directly to the ZnO seed layer prior to microwave assisted synthesis revealed expressive differences regarding formation of the ZnO nanostructures. Structural characterization of the microwave synthesized materials was carried out by scanning electron microscopy (SEM and X-ray diffraction (XRD. The optical characterization has also been performed. The time resolved photocurrent of the devices in response to the UV turn on/off was investigated and it has been observed that the ZnO nanorod arrays grown on Whatman paper substrate present a responsivity 3 times superior than the ones grown on tracing paper. By using ZnO nanorods, the surface area-to-volume ratio will increase and will improve the sensor sensibility, making these types of materials good candidates for low cost and disposable UV sensors. The sensors were exposed to bending tests, proving their high stability, flexibility and adaptability to different surfaces.

  6. Performance of Dye-Sensitized Solar Cells (DSSCs) Fabricated with Zinc Oxide (ZnO) Nanpowders and Nanorods

    Science.gov (United States)

    Chatterjee, Suman

    2018-03-01

    Due to their high efficiencies, along with lower production costs, many researchers are working on dye-sensitized solar cells (DSSCs) over last few decades as a substitute technology for nonconventional energy. Nanostructured ZnO has got many interesting properties such as wide band gap, large exciton binding energy, good exciton stability, and high breakdown strength, which are applicable as DSSC electrodes. This present work compares the device properties of DSSC fabricated using ZnO nanorods on a ZnO film and ZnO nanopowders. Different types of ZnO photoanode and dye combinations are used to study the stability and photovoltaic properties of the DSSC cell. The photovoltaic properties of the ZnO-based DSSC samples were systematically investigated. The photovoltaic properties of fabricated cell obtained are discussed in the light of band structure and density of states of different types of ZnO nanolayers. The ZnO nanorods fabricated through the sol-gel route have more uniform thickness resulting in enhanced photovoltaic properties of the fabricated device.

  7. Microstructural, chemical and textural characterization of ZnO nanorods synthesized by aerosol assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Fuentes-Cobas, L.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C. [Centro de Investigación en Materiales Avanzados, S.C., Chihuahua, Chihuahua 31109 (Mexico); Pérez-García, S.A. [Centro de Investigación en Materiales Avanzados, S.C., Unidad Monterrey, Apodaca, Nuevo León 66600 (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx [Centro de Investigación en Materiales Avanzados, S.C., Chihuahua, Chihuahua 31109 (Mexico)

    2014-12-15

    ZnO nanorods were synthesized by aerosol assisted chemical vapor deposition onto TiO{sub 2} covered borosilicate glass substrates. Deposition parameters were optimized and kept constant. Solely the effect of different nozzle velocities on the growth of ZnO nanorods was evaluated in order to develop a dense and uniform structure. The crystalline structure was characterized by conventional X-ray diffraction in grazing incidence and Bragg–Brentano configurations. In addition, two-dimensional grazing incidence synchrotron radiation diffraction was employed to determine the preferred growth direction of the nanorods. Morphology and growth characteristics analyzed by electron microscopy were correlated with diffraction outcomes. Chemical composition was established by X-ray photoelectron spectroscopy. X-ray diffraction results and X-ray photoelectron spectroscopy showed the presence of wurtzite ZnO and anatase TiO{sub 2} phases. Morphological changes noticed when the deposition velocity was lowered to the minimum, indicated the formation of relatively vertically oriented nanorods evenly distributed onto the TiO{sub 2} buffer film. By coupling two-dimensional X-ray diffraction and computational modeling with ANAELU it was proved that a successful texture determination was achieved and confirmed by scanning electron microscopy analysis. Texture analysis led to the conclusion of a preferred growth direction in [001] having a distribution width Ω = 20° ± 2°. - Highlights: • Uniform and pure single-crystal ZnO nanorods were obtained by AACVD technique. • Longitudinal and transversal axis parallel to the [001] and [110] directions, respectively. • Texture was determined by 2D synchrotron diffraction and electron microscopy analysis. • Nanorods have its [001] direction distributed close to the normal of the substrate. • Angular spread about the preferred orientation is 20° ± 2°.

  8. Flexible organic/inorganic hybrid solar cells based on conjugated polymer and ZnO nanorod array

    International Nuclear Information System (INIS)

    Tong, Fei; Kim, Kyusang; Martinez, Daniel; Thapa, Resham; Ahyi, Ayayi; Williams, John; Park, Minseo; Kim, Dong-Joo; Lee, Sungkoo; Lim, Eunhee; Lee, Kyeong K

    2012-01-01

    We report on the photovoltaic characteristics of organic/inorganic hybrid solar cells fabricated on ‘flexible’ transparent substrates. The solar cell device is composed of ZnO nanorod array and the bulk heterojunction structured organic layer which is the blend of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C61 butyric acid methyl ester (PCBM). The ZnO nanorod array was grown on indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates via a low-temperature (85 °C) aqueous solution process. The blend solution consisting of conjugated polymer P3HT and fullerene PCBM was spin coated at a low spinning rate of 400 rpm on top of the ZnO nanorod array structure and then the photoactive layer was slow dried at room temperature in air to promote its infiltration into the nanorod network. As a top electrode, silver was sputtered on top of the photoactive layer. The flexible solar cell with the structure of PET/ITO/ZnO thin film/ZnO nanorods/P3HT:PCBM/Ag exhibited a photovoltaic performance with an open circuit voltage (V OC ) of 0.52 V, a short circuit current density (J SC ) of 9.82 mA cm −2 , a fill factor (FF) of 35% and a power conversion efficiency (η) of 1.78%. All the measurements were performed under 100 mW cm −2 of illumination with an air mass 1.5 G filter. To the best of our knowledge, this is the first presentation of investigation into the fabrication and characterization of organic/inorganic hybrid solar cells based on bulk heterojunction structured conjugated polymer/fullerene photoactive layer and ZnO nanorod array constructed on flexible transparent substrates. (paper)

  9. Properties of In–N codoped p-type ZnO nanorods grown through a two-step chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Duta, M.; Mihaiu, S.; Munteanu, C. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Anastasescu, M., E-mail: manastasescu@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Osiceanu, P.; Marin, A.; Preda, S. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Nicolescu, M., E-mail: mnicolescu2006@yahoo.com [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Modreanu, M. [Tyndall National Institute, University College, Cork (Ireland); Zaharescu, M.; Gartner, M. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania)

    2015-07-30

    Highlights: • p-Type ZnO film codoped with In, N on glass substrate was obtained. • The films were prepared by sol–gel followed by hydrothermal method. • Influence of annealing regimes on opto-electrical properties was studied. • Thin films morphology consists of interconnected, randomly oriented nanorods. • 3.31 × 10{sup 17} cm{sup −3}carrier concentration and 85% transmission were obtained at 500 °C. - Abstract: By codoping with a donor–acceptor pair through a two-step chemical method we have succeed to obtain p-type ZnO thin films on glass. Firstly, a thin undoped ZnO seed layer was deposited by sol–gel method followed by the deposition of In–N codoped ZnO film obtained through the hydrothermal technique. The influence of post-deposition annealing temperature (100 °C, 300 °C and 500 °C) on the samples was investigated from a structural, chemical, morphological and optoelectrical point of view. X-ray diffractometry (XRD), infrared ellipsometry and X-ray photoelectron spectroscopy (XPS) analyses have confirmed the codoped nature of the ZnO thin films. The XRD pattern analysis has established the films have wurtzite nanocrystalline structure, the crystallite sizes varying between 10 nm and 13 nm with the annealing temperature. Continuous and homogenous films with nanorods surface morphology has been obtained, as visualized by scanning electron microscopy measurements. Hall Effect measurements have established that all samples, regardless of annealing temperature, showed p-type conduction due to the successful incorporation of nitrogen in the film, with the highest carrier concentration registered at 500 °C. This is in good correlation with the nitrogen content in the films as revealed from XPS. In all samples, the XPS depth profiling has shown a nitrogen gradient with higher elemental concentration at the surface.

  10. Effects of Doping with Al, Ga, and In on Structural and Optical Properties of ZnO Nanorods Grown by Hydrothermal Method

    International Nuclear Information System (INIS)

    Kim, Soaram; Nam, Giwoong; Park, Hyunggil; Yoon, Hyunsik; Leem, Jaeyoung; Lee, Sangheon; Kim, Jong Su; Kim, Jin Soo; Kim, Do Yeob; Kim, Sungo

    2013-01-01

    The structural and optical properties of the ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO nanorods were investigated using field-emission scanning electron microscopy, X-ray diffraction, photoluminescence (PL) and ultraviolet-visible spectroscopy. All the nanorods grew with good alignment on the ZnO seed layers and the ZnO nanorod dimensions could be controlled by the addition of the various dopants. For instance, the diameter of the nanorods decreased with increasing atomic number of the dopants. The ratio between the near-band-edge emission (NBE) and the deep-level emission (DLE) intensities (I NBE /I DLE ) obtained by PL gradually decreased because the DLE intensity from the nanorods gradually increased with increase in the atomic number of the dopants. We found that the dopants affected the structural and optical properties of the ZnO nanorods including their dimensions, lattice constants, residual stresses, bond lengths, PL properties, transmittance values, optical band gaps, and Urbach energies

  11. Effects of Doping with Al, Ga, and In on Structural and Optical Properties of ZnO Nanorods Grown by Hydrothermal Method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soaram; Nam, Giwoong; Park, Hyunggil; Yoon, Hyunsik; Leem, Jaeyoung [Inje Univ., Gimhae (Korea, Republic of); Lee, Sangheon; Kim, Jong Su [Yeungnam Univ., Gyeongsan (Korea, Republic of); Kim, Jin Soo [Chonbuk National Univ., Jeonju (Korea, Republic of); Kim, Do Yeob; Kim, Sungo [Clemson Univ., Clemson (United States)

    2013-04-15

    The structural and optical properties of the ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO nanorods were investigated using field-emission scanning electron microscopy, X-ray diffraction, photoluminescence (PL) and ultraviolet-visible spectroscopy. All the nanorods grew with good alignment on the ZnO seed layers and the ZnO nanorod dimensions could be controlled by the addition of the various dopants. For instance, the diameter of the nanorods decreased with increasing atomic number of the dopants. The ratio between the near-band-edge emission (NBE) and the deep-level emission (DLE) intensities (I{sub NBE}/I{sub DLE}) obtained by PL gradually decreased because the DLE intensity from the nanorods gradually increased with increase in the atomic number of the dopants. We found that the dopants affected the structural and optical properties of the ZnO nanorods including their dimensions, lattice constants, residual stresses, bond lengths, PL properties, transmittance values, optical band gaps, and Urbach energies.

  12. Effects of growth duration on the structural and optical properties of ZnO nanorods grown on seed-layer ZnO/polyethylene terephthalate substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y.I.; Shin, C.M.; Heo, J.H. [Department of Nano Systems Engineering, Center for Nano Manufacturing Inje University, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, H., E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing Inje University, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, W.J. [Department of Nano Engineering, Dong-Eui University, Busan 614-714 (Korea, Republic of); Chang, J.H. [Major of Nano Semiconductor, Korea Maritime University, Busan 606-791 (Korea, Republic of); Son, C.S. [Department of Electronic Materials Engineering, Silla University, Busan 617-736 (Korea, Republic of); Yun, J. [Department of Nano Science and Engineering, Institute of Advanced Materials Kyungnam University, Changwon, Gyeongnam 631-701 (Korea, Republic of)

    2011-10-01

    Well-aligned single crystalline zinc oxide (ZnO) nanorods were successfully grown, by hydrothermal synthesis at a low temperature, on flexible polyethylene terephthalate (PET) substrates with a seed layer. Photoluminescence (PL), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) measurements were used to analyze the optical and structural properties of ZnO nanorods grown for various durations from 0.5 h to 10 h. Regular and well-aligned ZnO nanorods with diameters ranging from 62 nm to 127 nm and lengths from 0.3 {mu}m to 1.65 {mu}m were formed after almost 5 h of growth. The growth rate of ZnO grown on PET substrates is lower than that grown on Si (1 0 0) substrates. Enlarged TEM images show that the tips of the ZnO nanorods grown for 6 h have a round shape, whereas the tips grown for 10 h are sharpened. The crystal properties of ZnO nanorods can be tuned by using the growth duration as a growth condition. The XRD and PL results indicate that the structural and optical properties of the ZnO nanorods are most improved after 5 h and 6 h of growth, respectively.

  13. Electrosynthesis of ZnO nanorods and nanotowers: Morphology and X-ray Absorption Near Edge Spectroscopy studies

    Science.gov (United States)

    Sigircik, Gokmen; Erken, Ozge; Tuken, Tunc; Gumus, Cebrail; Ozkendir, Osman M.; Ufuktepe, Yuksel

    2015-06-01

    Deposition mechanism of nano-structured ZnO films has been investigated in the absence and presence of chloride ions from aqueous solution. The resulting opto-electronic properties were interpreted extensively, using X-ray diffraction (XRD), X-ray Absorption Near Edge Spectroscopy (XANES), field emission scanning electron microscopy (FE-SEM), UV-Visible spectroscopy and four probe techniques. The ZnO deposition is mass transport controlled process and the interaction of chloride ions with the surface has great influence on diffusion kinetics, considering the substantial species (Zn2+ and OH-) involved in the construction of ZnO film. This effect does not change major lattice parameters, as shown with detailed analysis of XRD data. However, the texture coefficient (Tc) (0 0 2) value is higher in presence of chloride ions containing synthesis solution which gave vertically aligned, well defined and uniformly dispersed nanorods structure. The calculated Eg values are in the range 3.28-3.41 eV and 3.22-3.31 eV for ZnO nanorods and nanotowers synthesized at different deposition periods, respectively. Furthermore, the charge mobility values regarding the deposition periods were measured to be in the ranges from 130.4 to 449.2 cm2 V-1 s-1 and 126.2 to 204.7 cm2 V-1 s-1 for nanorods and nanotowers, respectively. From XANES results, it was shown that the Zn K-edge spectrum is dominated by the transition of Zn 1s core electrons into the unoccupied Zn 4p states of the conduction band. Comparing the rod and tower nano-structured ZnO thin films, the excitation behavior of valence band electrons is different. Moreover, the density states of Zn 4p are higher for ZnO nanorods.

  14. Three-dimensional carbon cloth-supported ZnO nanorod arrays as a binder-free anode for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lanyan; Wang, Xin, E-mail: wangxin@scnu.edu.cn [South China Normal University, Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics (China); Yin, Fuxing [Synergy Innovation Institute of GDUT (China); Zhang, Chengwei [Hebei University of Technology, Research Institute for Energy Equipment Materials, Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology (China); Gao, Jinwei; Liu, Junming [South China Normal University, Institute of Advanced Materials, South China Academy of Advanced Optoelectronics (China); Zhou, Guofu [South China Normal University, Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics (China); Zhang, Yongguang, E-mail: yongguangzhang@hebut.edu.cn; Bakenov, Zhumabay [Synergy Innovation Institute of GDUT (China)

    2017-02-15

    Three-dimensional ZnO nanorod arrays on flexible high surface area carbon cloth were successfully synthesized and directly used as negative electrodes for lithium-ion batteries without using any binder additive. The structure and morphology of the as-prepared hybrid ZnO electrode were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). When tested as anodes in a lithium cell, the hybrid electrode demonstrated a high discharge capacity along with excellent rate capability and good cycling stability, delivering a reversible capacity of 891 mAh g{sup −1} at the second cycle and retaining a capacity of 469 mAh g{sup −1} after 100 cycles.

  15. In situ reduced graphene oxide interlayer for improving electrode performance in ZnO nanorods

    Science.gov (United States)

    Venkatesan, A.; Ramesha, C. K.; Kannan, E. S.

    2016-06-01

    The effect of reduced graphene oxide (RGO) thin film on the transport characteristics of vertically aligned zinc oxide nanorods (ZnO NRs) grown on ITO substrate was studied. GO was uniformly drop casted on ZnO NRs as a passivation layer and then converted into RGO by heating it at 60 °C prior to metal electrode deposition. This low temperature reduction is facilitated by the thermally excited electrons from ZnI interstitial sites (~30 meV). Successful reduction of GO was ascertained from the increased disorder band (D) intensity in the Raman spectra. Temperature (298 K-10 K) dependent transport measurements of RGO-ZnO NRs indicate that the RGO layer not only acts as a short circuiting inhibitor but also reduces the height of the potential barrier for electron tunneling. This is confirmed from the temperature dependent electrical characteristics which revealed a transition of carrier transport from thermionic emission at high temperature (T  >  100 K) to tunneling at low temperature (T  <  100 K) across the interface. Our technique is the most promising approach for making reliable electrical contacts on vertically aligned ZnO NRs and improving the reproducibility of device characteristics.

  16. PDMS-based triboelectric and transparent nanogenerators with ZnO nanorod arrays.

    Science.gov (United States)

    Ko, Yeong Hwan; Nagaraju, Goli; Lee, Soo Hyun; Yu, Jae Su

    2014-05-14

    Vertically-grown ZnO nanorod arrays (NRAs) on indium tin oxide (ITO)-coated polyethylene terephthalate (PET), as a top electrode of nanogenerators, were investigated for the antireflective property as well as an efficient contact surface in bare polydimethysiloxane (PDMS)-based triboelectric nanogenerators. Compared to conventional ITO-coated PET (i.e., ITO/PET), the ZnO NRAs considerably suppressed the reflectance from 20 to 9.7% at wavelengths of 300-1100 nm, creating a highly transparent top electrode, as demonstrated by theoretical analysis. Also, the interval time between the peaks of generated output voltage under external pushing forces was significantly decreased from 1.84 to 0.19 s because the reduced contact area of the PDMS by discrete surfaces of the ZnO NRAs on ITO/PET causes a rapid sequence for triboelectric charge generation process including rubbing and separating. Therefore, the use of this top electrode enabled to operate the transparent PDMS-based triboelectric nanogenerator at high frequency of external pushing force. Under different external forces of 0.3-10 kgf, the output voltage and current were also characterized.

  17. Controlling the conduction band offset for highly efficient ZnO nanorods based perovskite solar cell

    International Nuclear Information System (INIS)

    Dong, Juan; Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2015-01-01

    The mechanism of charge recombination at the interface of n-type electron transport layer (n-ETL) and perovskite absorber on the carrier properties in the perovskite solar cell is theoretically studied. By solving the one dimensional diffusion equation with different boundary conditions, it reveals that the interface charge recombination in the perovskite solar cell can be suppressed by adjusting the conduction band offset (ΔE C ) at ZnO ETL/perovskite absorber interface, thus leading to improvements in cell performance. Furthermore, Mg doped ZnO nanorods ETL has been designed to control the energy band levels. By optimizing the doping amount of Mg, the conduction band minimum of the Mg doped ZnO ETL has been raised up by 0.29 eV and a positive ΔE C of about 0.1 eV is obtained. The photovoltage of the cell is thus significantly increased due to the relatively low charge recombination

  18. Growing vertical ZnO nanorod arrays within graphite: efficient isolation of large size and high quality single-layer graphene.

    Science.gov (United States)

    Ding, Ling; E, Yifeng; Fan, Louzhen; Yang, Shihe

    2013-07-18

    We report a unique strategy for efficiently exfoliating large size and high quality single-layer graphene directly from graphite into DMF dispersions by growing ZnO nanorod arrays between the graphene layers in graphite.

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

    Science.gov (United States)

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

    2018-01-01

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

  20. Electrosynthesis of ZnO nanorods and nanotowers: Morphology and X-ray Absorption Near Edge Spectroscopy studies

    Energy Technology Data Exchange (ETDEWEB)

    Sigircik, Gokmen, E-mail: gsigircik@cu.edu.tr [Chemistry Department, University of Cukurova, 01330 Adana (Turkey); Erken, Ozge [Department of Physics, Faculty Science and Letters, Adiyaman University, 02040 Adiyaman (Turkey); Tuken, Tunc [Chemistry Department, University of Cukurova, 01330 Adana (Turkey); Gumus, Cebrail [Physics Department, University of Cukurova, 01330 Adana (Turkey); Ozkendir, Osman M. [Department of Energy Systems Engineering Tarsus Technology Faculty, Mersin University, 33400 Tarsus (Turkey); Ufuktepe, Yuksel [Physics Department, University of Cukurova, 01330 Adana (Turkey)

    2015-06-15

    Highlights: • Deposition mechanism of nano-structured ZnO films has been investigated in the absence and presence of chloride ions from aqueous solution. • Uniform and well-defined ZnO nano-towers and rods have been obtained via electrochemical deposition. • The presence of chloride ions altered the nucleation rate of ZnO particles on ITO substrates and resulting crystallographic properties. • Comparing the rod and tower nano-structured ZnO thin films, the excitation behavior of valance band electrons is different. - Abstract: Deposition mechanism of nano-structured ZnO films has been investigated in the absence and presence of chloride ions from aqueous solution. The resulting opto-electronic properties were interpreted extensively, using X-ray diffraction (XRD), X-ray Absorption Near Edge Spectroscopy (XANES), field emission scanning electron microscopy (FE-SEM), UV-Visible spectroscopy and four probe techniques. The ZnO deposition is mass transport controlled process and the interaction of chloride ions with the surface has great influence on diffusion kinetics, considering the substantial species (Zn{sup 2+} and OH{sup −}) involved in the construction of ZnO film. This effect does not change major lattice parameters, as shown with detailed analysis of XRD data. However, the texture coefficient (T{sub c}) (0 0 2) value is higher in presence of chloride ions containing synthesis solution which gave vertically aligned, well defined and uniformly dispersed nanorods structure. The calculated E{sub g} values are in the range 3.28–3.41 eV and 3.22–3.31 eV for ZnO nanorods and nanotowers synthesized at different deposition periods, respectively. Furthermore, the charge mobility values regarding the deposition periods were measured to be in the ranges from 130.4 to 449.2 cm{sup 2} V{sup −1} s{sup −1} and 126.2 to 204.7 cm{sup 2} V{sup −1} s{sup −1} for nanorods and nanotowers, respectively. From XANES results, it was shown that the Zn K

  1. Electrosynthesis of ZnO nanorods and nanotowers: Morphology and X-ray Absorption Near Edge Spectroscopy studies

    International Nuclear Information System (INIS)

    Sigircik, Gokmen; Erken, Ozge; Tuken, Tunc; Gumus, Cebrail; Ozkendir, Osman M.; Ufuktepe, Yuksel

    2015-01-01

    Highlights: • Deposition mechanism of nano-structured ZnO films has been investigated in the absence and presence of chloride ions from aqueous solution. • Uniform and well-defined ZnO nano-towers and rods have been obtained via electrochemical deposition. • The presence of chloride ions altered the nucleation rate of ZnO particles on ITO substrates and resulting crystallographic properties. • Comparing the rod and tower nano-structured ZnO thin films, the excitation behavior of valance band electrons is different. - Abstract: Deposition mechanism of nano-structured ZnO films has been investigated in the absence and presence of chloride ions from aqueous solution. The resulting opto-electronic properties were interpreted extensively, using X-ray diffraction (XRD), X-ray Absorption Near Edge Spectroscopy (XANES), field emission scanning electron microscopy (FE-SEM), UV-Visible spectroscopy and four probe techniques. The ZnO deposition is mass transport controlled process and the interaction of chloride ions with the surface has great influence on diffusion kinetics, considering the substantial species (Zn 2+ and OH − ) involved in the construction of ZnO film. This effect does not change major lattice parameters, as shown with detailed analysis of XRD data. However, the texture coefficient (T c ) (0 0 2) value is higher in presence of chloride ions containing synthesis solution which gave vertically aligned, well defined and uniformly dispersed nanorods structure. The calculated E g values are in the range 3.28–3.41 eV and 3.22–3.31 eV for ZnO nanorods and nanotowers synthesized at different deposition periods, respectively. Furthermore, the charge mobility values regarding the deposition periods were measured to be in the ranges from 130.4 to 449.2 cm 2 V −1 s −1 and 126.2 to 204.7 cm 2 V −1 s −1 for nanorods and nanotowers, respectively. From XANES results, it was shown that the Zn K-edge spectrum is dominated by the transition of Zn 1s core

  2. Impact of first-step potential and time on the vertical growth of ZnO nanorods on ITO substrate by two-step electrochemical deposition

    International Nuclear Information System (INIS)

    Kim, Tae Gyoum; Jang, Jin-Tak; Ryu, Hyukhyun; Lee, Won-Jae

    2013-01-01

    Highlights: •We grew vertical ZnO nanorods on ITO substrate using a two-step continuous potential process. •The nucleation for the ZnO nanorods growth was changed by first-step potential and duration. •The vertical ZnO nanorods were well grown when first-step potential was −1.2 V and 10 s. -- Abstract: In this study, we analyzed the growth of ZnO nanorods on an ITO (indium doped tin oxide) substrate by electrochemical deposition using a two-step, continuous potential process. We examined the effect of changing the first-step potential as well as the first-step duration on the morphological, structural and optical properties of ZnO nanorods, measured via using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and photoluminescence (PL), respectively. As a result, vertical ZnO nanorods were grown on ITO substrate without the need for a template when the first-step potential was set to −1.2 V for a duration of 10 s, and the second-step potential was set to −0.7 V for a duration of 1190 s. The ZnO nanorods on this sample showed the highest XRD (0 0 2)/(1 0 0) peak intensity ratio and the highest PL near band edge emission to deep level emission peak intensity ratio (NBE/DLE). In this study, the nucleation for vertical ZnO nanorod growth on an ITO substrate was found to be affected by changes in the first-step potential and first-step duration

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-05

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  5. Nanofabrication and characterization of ZnO nanorod arrays and branched microrods by aqueous solution route and rapid thermal processing

    International Nuclear Information System (INIS)

    Lupan, Oleg; Chow, Lee; Chai, Guangyu; Roldan, Beatriz; Naitabdi, Ahmed; Schulte, Alfons; Heinrich, Helge

    2007-01-01

    This paper presents an inexpensive and fast fabrication method for one-dimensional (1D) ZnO nanorod arrays and branched two-dimensional (2D), three-dimensional (3D) - nanoarchitectures. Our synthesis technique includes the use of an aqueous solution route and post-growth rapid thermal annealing. It permits rapid and controlled growth of ZnO nanorod arrays of 1D - rods, 2D - crosses, and 3D - tetrapods without the use of templates or seeds. The obtained ZnO nanorods are uniformly distributed on the surface of Si substrates and individual or branched nano/microrods can be easily transferred to other substrates. Process parameters such as concentration, temperature and time, type of substrate and the reactor design are critical for the formation of nanorod arrays with thin diameter and transferable nanoarchitectures. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and Micro-Raman spectroscopy have been used to characterize the samples

  6. Controlled synthesis of ZnO branched nanorod arrays by hierarchical solution growth and application in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Fang Xiaoming; Peng Lihua; Shang Xiaoying; Zhang Zhengguo

    2011-01-01

    We demonstrate the controlled synthesis of ZnO branched nanorod arrays on fluorine-doped SnO 2 -coated glass substrates by the hierarchical solution growth method. In the secondary growth, the concentration of Zn(NO 3 ) 2 /hexamethylenetetramine plays an important role in controlling the morphology of the branched nanorod arrays, besides that of diaminopropane used as a structure-directing agent to induce the growth of branches. The population density and morphology of the branched nanorod arrays depend on those of the nanorod arrays obtained from the primary growth, which can be modulated though the concentration of Zn(NO 3 ) 2 /hexamethylenetetramine in the primary growth solution. The dye-sensitized ZnO branched nanorod arrays exhibit much stronger optical absorption as compared with its corresponding primary nanorod arrays, suggesting that the addition of the branches improves light harvesting. The dye-sensitized solar cell based on the optimized ZnO branched nanorod array reaches a conversion efficiency of 1.66% under the light radiation of 1000 W/m 2 . The branched nanorod arrays can also be applied in other application fields of ZnO.

  7. Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO2 Photoanodes

    Directory of Open Access Journals (Sweden)

    Bao-gai Zhai

    2017-01-01

    Full Text Available By increasing the temperature of hydrothermal reactions from 70 to 100°C, vertically aligned ZnO nanorods were grown on the TiO2 thin film in the photoanode of dye-sensitized solar cells (DSSCs as the blocking layer to reduce the electron back recombinations at the TiO2/electrolyte interfaces. The length effects of ZnO nanorods on the photovoltaic performances of TiO2 based DSSCs were investigated by means of scanning electron microscope, X-ray diffractometer, photoluminescence spectrophotometer, and the photocurrent-voltage measurement. Under the illumination of 100 mW/cm2, the power conversion efficiency of DSSC with ZnO nanorods decorated TiO2 thin film as its photoanode can be increased nearly fourfold from 0.27% to 1.30% as the length of ZnO nanorods increases from 300 to 1600 nm. The enhanced efficiency of DSSC with ZnO nanorods decorated TiO2 thin film as the photoanode can be attributed to the larger surface area and the lower defect density in longer ZnO nanorods, which are in favor of more dye adsorption and more efficient transport in the photoanode.

  8. Preparation of ZnO nanocrystals via ultrasonic irradiation

    DEFF Research Database (Denmark)

    Qian, D.; Jiang, Jianzhong; Hansen, P. L.

    2003-01-01

    A simple and rapid process has been developed for the preparation of nanometer-sized ZnO crystals via ultrasonic irradiation, by which pure ZnO nanocrystals with an average size of 6 nm and narrow size distribution can be synthesized in a short time and without using any solvents for the precipit......A simple and rapid process has been developed for the preparation of nanometer-sized ZnO crystals via ultrasonic irradiation, by which pure ZnO nanocrystals with an average size of 6 nm and narrow size distribution can be synthesized in a short time and without using any solvents...

  9. Optical and structural properties of Mn-doped ZnO nanorods grown by aqueous chemical growth for spintronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Strelchuk, V.V. [V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 45 Nauky pr., 03028 Kyiv (Ukraine); Nikolenko, A.S., E-mail: nikolenko_mail@ukr.net [V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 45 Nauky pr., 03028 Kyiv (Ukraine); Kolomys, O.F.; Rarata, S.V.; Avramenko, K.A.; Lytvyn, P.M. [V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 45 Nauky pr., 03028 Kyiv (Ukraine); Tronc, P. [Centre National de la Recherche Scientifique, Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris, 10 rue Vauquelin, 75005 Paris (France); Chey, Chan Oeurn; Nur, Omer; Willander, Magnus [Department of Science and Technology, Linköping University, 601 74 Norrköping (Sweden)

    2016-02-29

    The effect of Mn-doping on the structural, morphological, optical and magnetic properties of the ZnO:Mn nanorods (NRs) synthesized by aqueous chemical process is reported. Grown ZnO:Mn NRs are shown to have hexagonal end facets and the diameters increasing with nominal Mn content. Optical absorption measurements show a decrease in optical band gap with increase of Mn concentration. Raman spectroscopy revealed significant modification of the lattice vibrational properties of the ZnO matrix upon Mn doping. The additional Mn-related vibrational mode, intensity of which increases with amount of Mn can be regarded as an evidence of Mn incorporation into the host lattice of the ZnO. At high Mn concentrations, coexistence of hexagonal Zn{sub 1−x}Mn{sub x}O phase along with the secondary phases of ZnMn{sub 2}O{sub 4} cubic spinel is revealed. Magnetic properties of ZnO:Mn NRs are studied by combinatorial atomic force microscopy and magnetic force microscopy imaging, and obtained clear magnetic contrast at room temperature provides a strong evidence of ferromagnetic behavior. - Highlights: • Synthesis of Mn-doped ZnO nanorods by hydrothermal method is demonstrated. • Doping with Mn significantly changes the morphology of ZnO nanorods. • Additional Mn-induced Raman modes evidence incorporation of Mn into ZnO matrix. • Formation of secondary ZnMn{sub 2}O{sub 4} spinel phase is found at high Mn concentrations. • Contrast MFM images of ZnO:Mn nanorods indicate ferromagnetism at room temperature.

  10. Surface characterization of ZnO nanorods grown by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mbulanga, C.M., E-mail: crispin.mbulanga@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Urgessa, Z.N.; Tankio Djiokap, S.R.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Duvenhage, M.M.; Swart, H.C. [Department of Physics, University of the Free State, P.O Box 77000, Bloemfontein ZA9300 (South Africa)

    2016-01-01

    The surface composition of as-grown and annealed ZnO nanorods (ZNs) grown by a two-step chemical bath deposition method is investigated by the following surface-sensitive techniques: Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The presence of H on the surface and throughout the entire thickness of ZNs is confirmed by TOF-SIMS. Based on TOF-SIMS results, the O2 XPS peak mostly observable at ~531.5 is assigned to O bound to H. Furthermore, it is found that the near surface region of as-grown ZNs is Zn-rich, and annealing at high temperature (~850 °C) removes H-related defects from the surface of ZNs and affect the balance of zinc and oxygen concentrations.

  11. Photoluminescence study of aligned ZnO nanorods grown using chemical bath deposition

    International Nuclear Information System (INIS)

    Urgessa, Z.N.; Oluwafemi, O.S.; Dangbegnon, J.K.; Botha, J.R.

    2012-01-01

    The photoluminescence study of self-assembled ZnO nanorods grown on a pre-treated Si substrate by a simple chemical bath deposition method at a temperature of 80 °C is hereby reported. By annealing in O 2 environment the UV emission is enhanced with diminishing deep level emission suggesting that most of the deep level emission is due to oxygen vacancies. The photoluminescence was investigated from 10 K to room temperature. The low temperature photoluminescence spectrum is dominated by donor-bound exciton. The activation energy and binding energy of shallow donors giving rise to bound exciton emission were calculated to be around 13.2 meV, 46 meV, respectively. Depending on these energy values and nature of growth environment, hydrogen is suggested to be the possible contaminating element acting as a donor.

  12. Photoluminescence study of aligned ZnO nanorods grown using chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Urgessa, Z.N. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Oluwafemi, O.S. [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag XI, 5117 (South Africa); Dangbegnon, J.K. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Botha, J.R., E-mail: Reinhardt.Botha@nmmu.ac.za [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-05-15

    The photoluminescence study of self-assembled ZnO nanorods grown on a pre-treated Si substrate by a simple chemical bath deposition method at a temperature of 80 Degree-Sign C is hereby reported. By annealing in O{sub 2} environment the UV emission is enhanced with diminishing deep level emission suggesting that most of the deep level emission is due to oxygen vacancies. The photoluminescence was investigated from 10 K to room temperature. The low temperature photoluminescence spectrum is dominated by donor-bound exciton. The activation energy and binding energy of shallow donors giving rise to bound exciton emission were calculated to be around 13.2 meV, 46 meV, respectively. Depending on these energy values and nature of growth environment, hydrogen is suggested to be the possible contaminating element acting as a donor.

  13. Field emission from carbon nanotube bundle arrays grown on self-aligned ZnO nanorods

    International Nuclear Information System (INIS)

    Li Chun; Fang Guojia; Yuan Longyan; Liu Nishuang; Ai Lei; Xiang Qi; Zhao Dongshan; Pan Chunxu; Zhao Xingzhong

    2007-01-01

    The field emission (FE) properties of carbon nanotube (CNT) bundle arrays grown on vertically self-aligned ZnO nanorods (ZNRs) are reported. The ZNRs were first synthesized on ZnO-seed-coated Si substrate by the vapour phase transport method, and then the radically grown CNTs were grown directly on the surface of the ZNRs from ethanol flames. The CNT/ZNR composite showed a turn-on field of 1.5 V μm -1 (at 0.1 μA cm -2 ), a threshold field of 4.5 V μm -1 (at 1 mA cm -2 ) and a stable emission current with fluctuations of 5%, demonstrating significantly enhanced FE of ZNRs due to the low work function and high aspect ratio of the CNTs, and large surface-to-volume ratio of the underlying ZNRs

  14. IGZO thin film transistor biosensors functionalized with ZnO nanorods and antibodies.

    Science.gov (United States)

    Shen, Yi-Chun; Yang, Chun-Hsu; Chen, Shu-Wen; Wu, Shou-Hao; Yang, Tsung-Lin; Huang, Jian-Jang

    2014-04-15

    We demonstrate a biosensor structure consisting of an IGZO (Indium-Gallium-Zinc-Oxide) TFT (thin film transistor) and an extended sensing pad. The TFT acts as the sensing and readout device, while the sensing pad ensures the isolation of biological solution from the transistor channel layer, and meanwhile increases the sensing area. The biosensor is functionalized by first applying ZnO nanorods to increase the surface area for attracting electrical charges of EGFR (epidermal growth factor receptor) antibodies. The device is able to selectively detect 36.2 fM of EGFR in the total protein solution of 0.1 ng/ml extracted from squamous cell carcinoma (SCC). Furthermore, the conjugation duration of the functionalized device with EGFR can be limited to 3 min, implying that the biosensor has the advantage for real-time detection. © 2013 Elsevier B.V. All rights reserved.

  15. Field enhancement of multiphoton induced luminescence processes in ZnO nanorods

    Science.gov (United States)

    Hyyti, Janne; Perestjuk, Marko; Mahler, Felix; Grunwald, Rüdiger; Güell, Frank; Gray, Ciarán; McGlynn, Enda; Steinmeyer, Günter

    2018-03-01

    The near-ultraviolet photoluminescence of ZnO nanorods induced by multiphoton absorption of unamplified Ti:sapphire pulses is investigated. Power dependence measurements have been conducted with an adaptation of the ultrashort pulse characterization method of interferometric frequency-resolved optical gating. These measurements enable the separation of second harmonic and photoluminescence bands due to their distinct coherence properties. A detailed analysis yields fractional power dependence exponents in the range of 3-4, indicating the presence of multiple nonlinear processes. The range in measured exponents is attributed to differences in local field enhancement, which is supported by independent photoluminescence and structural measurements. Simulations based on Keldysh theory suggest contributions by three- and four-photon absorption as well as avalanche ionization in agreement with experimental findings.

  16. Effect of TiO{sub 2} thickness on nanocomposited aligned ZnO nanorod/TiO{sub 2} for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Saurdi, I., E-mail: saurdy788@gmail.com; Ishak, A. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); UiTM Sarawak Kampus Kota Samarahan Jalan Meranek, Sarawak (Malaysia); Shafura, A. K.; Azhar, N. E. A.; Mamat, M. H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); Malek, M. F.; Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), (Centre for Nano-Science and Nano-Technology), Institute of Science - IOS, Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Alrokayan, A. H. Salman; Khan, Haseeb A. [Department of Biochemistry, College of Science, Bldg. 5, King Saud University (KSU) P.O: 2455 Riyadh 1145 (Saudi Arabia)

    2016-07-06

    The TiO{sub 2} films were deposited on glass substrate at different thicknesses with different deposition frequencies (1, 2, 3 and 4 times) using spin coating technique and their structural properties were investigated. Subsequently, the nanocomposited aligned ZnO nanorods and TiO{sub 2} were formed by deposited the TiO{sub 2} on top of aligned ZnO Nanorod on ITO-coated glass at different thicknesses using the same method of TiO{sub 2} deposited on glass substrate. The nanocomposited aligned ZnO nanorod/TiO{sub 2} were coated with different thicknesses of 900µm, 1815µm, 2710µm, 3620µm and ZnO without TiO{sub 2}. The dye-sensitized solar cells were fabricated from the nanocomposited aligned ZnO nanorod/TiO{sub 2} with thickness of 900µm, 1815µm, 2710µm and 3620µm and ZnO without TiO{sub 2} and their photovoltaic properties of the DSSCs were investigated. From the solar simulator measurement the solar energy conversion efficiency (η) of 2.543% under AM 1.5 was obtained for the ZnO nanorod/TiO{sub 2} photoanode-2710µm Dye-Sensitized solar cell.

  17. Organic solvent wetting properties of UV and plasma treated ZnO nanorods: printed electronics approach

    KAUST Repository

    Sliz, Rafal

    2012-09-13

    Due to low manufacturing costs, printed organic solar cells are on the short-list of renewable and environmentally- friendly energy production technologies of the future. However, electrode materials and each photoactive layer require different techniques and approaches. Printing technologies have attracted considerable attention for organic electronics due to their potentially high volume and low cost processing. A case in point is the interface between the substrate and solution (ink) drop, which is a particularly critical issue for printing quality. In addition, methods such as UV, oxygen and argon plasma treatments have proven suitable to increasing the hydrophilicity of treated surfaces. Among several methods of measuring the ink-substrate interface, the simplest and most reliable is the contact angle method. In terms of nanoscale device applications, zinc oxide (ZnO) has gained popularity, owing to its physical and chemical properties. In particular, there is a growing interest in exploiting the unique properties that the so-called nanorod structure exhibits for future 1-dimensional opto-electronic devices. Applications, such as photodiodes, thin-film transistors, sensors and photo anodes in photovoltaic cells have already been demonstrated. This paper presents the wettability properties of ZnO nanorods treated with UV illumination, oxygen and argon plasma for various periods of time. Since this work concentrates on solar cell applications, four of the most common solutions used in organic solar cell manufacture were tested: P3HT:PCBM DCB, P3HT:PCBM CHB, PEDOT:PSS and water. The achieved results prove that different treatments change the contact angle differently. Moreover, solvent behaviour varied uniquely with the applied treatment. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  18. ZnO nanorod based low turn-on voltage LEDs with wide electroluminescence spectra

    International Nuclear Information System (INIS)

    Jha, S.K.; Kutsay, O.; Bello, I.; Lee, S.T.

    2013-01-01

    Light emitting diodes (LEDs) based on arrays of n-type ZnO Nanorods were fabricated on p-GaN films using a hydrothermal method. The LEDs emit mainly in blue and UV range of the light. Their current–Voltage (I–V) characteristics typically show a low leakage current (7.2 μA) and a high rectification ratio (3 5 5). Devices operate at a low turn-on voltage of ∼4.5 V. Photoluminescence (PL) and electroluminescence (EL) measurements suggest low density of ZnO defects; however, in some aspects density of interfacial defects still might be considerable in the studied devices. The PL emission is deconvoluted to three peaks that are located at wavelengths of 361, 381, and 397 nm, while the wide EL spectra are deconvoluted to five peaks appearing at 368, 385, 427, 474, and 515 nm. Near-band-edge (NBE) emission of p-GaN and n-ZnO was observed in both the PL and EL spectra. Deconvoluted EL spectra consist of a very wide green band with the peak at 515 nm and extending up to 650 nm (red), and a rarely reported EL emission at 474 nm. Origin of these emissions is discussed, herein. The electrical characteristics together with EL characteristics indicate potential to develop and study p-GaN/n-ZnO nanorod LEDs for white emitting applications. - Highlights: ► A low turn-on voltage (4–4.5 V) and low threshold (5 V) electroluminescence from ZnO/GaN heterostructure. ► A wide spectrum EL emission (360–700 nm) suitable for white LED application. ► EL spectra consist of a rarely reported emission band with peak at 474 nm. ► Low-temperature and solution based fabrication, which is scalable and of low cost.

  19. Efficiency Enhancement of Dye-Sensitized Solar Cells’ Performance with ZnO Nanorods Grown by Low-Temperature Hydrothermal Reaction

    Directory of Open Access Journals (Sweden)

    Fang-I Lai

    2015-12-01

    Full Text Available In this study, aligned zinc oxide (ZnO nanorods (NRs with various lengths (1.5–5 µm were deposited on ZnO:Al (AZO-coated glass substrates by using a solution phase deposition method; these NRs were prepared for application as working electrodes to increase the photovoltaic conversion efficiency of solar cells. The results were observed in detail by using X-ray diffraction, field-emission scanning electron microscopy, UV-visible spectrophotometry, electrochemical impedance spectroscopy, incident photo-to-current conversion efficiency, and solar simulation. The results indicated that when the lengths of the ZnO NRs increased, the adsorption of D-719 dyes through the ZnO NRs increased along with enhancing the short-circuit photocurrent and open-circuit voltage of the cell. An optimal power conversion efficiency of 0.64% was obtained in a dye-sensitized solar cell (DSSC containing the ZnO NR with a length of 5 µm. The objective of this study was to facilitate the development of a ZnO-based DSSC.

  20. Photocatalytic paper using zinc oxide nanorods

    International Nuclear Information System (INIS)

    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.

  1. Preparation and characterization of dye-sensitized TiO{sub 2} nanorod solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Lijian, E-mail: ljm@isep.ipp.pt [Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); Centro de Física, Universidade do Minho, 4800-058 Guimarães (Portugal); Chen, Hong [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, fine Mechanics and Physics of Chinese Academy of Science, Changchun 130033 (China); Li, Can [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023,China (China); Santos, M.P. dos [CEFITEC, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Departamento de Física, Escola de Ciências e Tecnologia, Universidade de Évora (Portugal)

    2015-02-27

    TiO{sub 2} nanorods were prepared by DC reactive magnetron sputtering technique and applied to dye-sensitized solar cells (DSSCs). The length of the TiO{sub 2} nanorods was varied from 1 μm to 6 μm. The scanning electron microscopy images show that the nanorods are perpendicular to the substrate. Both the X-ray diffraction patterns and Raman scattering results show that the nanorods have an anatase phase; no other phase has been observed. (101) and the (220) diffraction peaks have been observed for the TiO{sub 2} nanorods. The (101) diffraction peak intensity remained constant despite the increase of nanorod length, while the intensity of the (220) diffraction peak increased almost linearly with the nanorod length. These nanorods were used as the working electrodes in DSSCs and the effect of the nanorod length on the conversion efficiency has been studied. An optimum photoelectric conversion efficiency of 4.8% has been achieved for 4 μm length nanorods. - Highlights: • [110] oriented TiO{sub 2} nanorods were deposited on ITO substrate by dc reactive magnetron sputtering. • The structural properties of these nanorods have been studied. • The (110) texture is dominated by strain energy minimization. • DSSCs were assembled using these nanorods as electrode.

  2. Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition

    Science.gov (United States)

    Barbagiovanni, E. G.; Strano, V.; Franzò, G.; Crupi, I.; Mirabella, S.

    2015-03-01

    Two deep level defects (2.25 and 2.03 eV) associated with oxygen vacancies (Vo) were identified in ZnO nanorods (NRs) grown by low cost chemical bath deposition. A transient behaviour in the photoluminescence (PL) intensity of the two Vo states was found to be sensitive to the ambient environment and to NR post-growth treatment. The largest transient was found in samples dried on a hot plate with a PL intensity decay time, in air only, of 23 and 80 s for the 2.25 and 2.03 eV peaks, respectively. Resistance measurements under UV exposure exhibited a transient behaviour in full agreement with the PL transient, indicating a clear role of atmospheric O2 on the surface defect states. A model for surface defect transient behaviour due to band bending with respect to the Fermi level is proposed. The results have implications for a variety of sensing and photovoltaic applications of ZnO NRs.

  3. Effects of High-Energy Proton-Beam Irradiation on the Magnetic Properties of ZnO Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Kue; Kwon, Hyeok-Jung; Cho, Yong Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    There are still many problem for the application due to its unstable magnetism state and too small magnetization values. Here we investigate magnetic properties of ZnO nanorods after high-energy proton-beam irradiation. Electron spin resonance (ESR) measurement on temperature was made to identify intrinsic or extrinsic defects as well as to observe magnetic ordering after irradiation. Understanding the effects of proton beam irradiation on magnetic behavior may help to shed light on the mechanism responsible for the magnetic ordering in this material. We have investigated proton-beam irradiation effects on the magnetic properties of ZnO nanorods. After irradiation a broad ESR line is observed, indicating emergence of ferromagnetic ordering up to room temperature. In M-H curve, stronger coercive field is observed after irradiation.

  4. Sulfur and Nitrogen co-doped graphene quantum dot decorated ZnO nanorod/polymer hybrid flexible device for photosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Hmar, Jehova Jire L.; Majumder, Tanmoy; Dhar, Saurab; Mondal, Suvra Prakash, E-mail: suvraphy@gmail.com

    2016-08-01

    S and N co-doped graphene quantum dots (S,N-GQDs) have been synthesized by a hydrothermal process. S,N-GQDs are made up of 1–5 monolayer of graphene with average diameter 13.3 nm. The absorption peaks at 336 and 621 nm, are attributed to n → Π{sup ⁎} transitions of electrons in C=O and S=O bonds, respectively. S,N-GQDs are highly luminescent and showed excitation dependent emission behaviors. Hybrid photosensing device has been fabricated with S,N-GQD sensitized ZnO nanorods and a conjugated polymer poly(3-hexylthiophene) (P3HT). S,N-GQD decorated ZnO nanorod demonstrated higher photoresponse compared to pristine ZnO nanorod based device. S,N-GQD/ZnO nanorod hybrid device showed superior incident photon to electron conversion efficiency (IPCE), photoresponsivity and detectivity compared to the control samples. The flexibility study of the samples has been monitored by measuring current-voltage characteristics at different bending angles. - Highlights: • S and N co-doped graphene quantum dots (S,N-GQDs) were synthesized. • ZnO nanorods were grown on ITO coated flexible PET substrates. • S,N-GQDs were attached with ZnO nanorods and used as a green sensitizer. • Photosensing properties of S,N-GQD/ZnO and P3HT polymer hybrid device was studied.

  5. Tuning of deep level emission in highly oriented electrodeposited ZnO nanorods by post growth annealing treatments

    International Nuclear Information System (INIS)

    Simimol, A.; Manikandanath, N. T.; Chowdhury, Prasanta; Barshilia, Harish C.; Anappara, Aji A.

    2014-01-01

    Highly dense and c-axis oriented zinc oxide (ZnO) nanorods with hexagonal wurtzite facets were deposited on fluorine doped tin oxide coated glass substrates by a simple and cost-effective electrodeposition method at low bath temperature (80 °C). The as-grown samples were then annealed at various temperatures (T A  = 100–500 °C) in different environments (e.g., zinc, oxygen, air, and vacuum) to understand their photoluminescence (PL) behavior in the ultra-violet (UV) and the visible regions. The PL results revealed that the as-deposited ZnO nanorods consisted of oxygen vacancy (V O ), zinc interstitial (Zn i ), and oxygen interstitial (O i ) defects and these can be reduced significantly by annealing in different environments at optimal annealing temperatures. However, the intensity of deep level emission increased for T A greater than the optimized values for the respective environments due to the introduction of various defect centers. For example, for T A  ≥ 450 °C in the oxygen and air environments, the density of O i defects increased, whereas, the green emission associated with V O is dominant in the vacuum annealed (T A  = 500 °C) ZnO nanorods. The UV peak red shifted after the post-growth annealing treatments in all the environments and the vacuum annealed sample exhibited highest UV peak intensity. The observations from the PL data are supported by the micro-Raman spectroscopy. The present study gives new insight into the origin of different defects that exist in the electrodeposited ZnO nanorods and how these defects can be precisely controlled in order to get the desired emissions for the opto-electronic applications

  6. Influence Applied Potential on the Formation of Self-Organized ZnO Nanorod Film and Its Photoelectrochemical Response

    Directory of Open Access Journals (Sweden)

    Nur Azimah Abd Samad

    2016-01-01

    Full Text Available The present paper reports on the facile formation of ZnO nanorod photocatalyst electrodeposited on Zn foil in the production of hydrogen gas via water photoelectrolysis. Based on the results, ZnO nanorod films were successfully grown via electrochemical deposition in an optimum electrolyte set of 0.5 mM zinc chloride and 0.1 M potassium chloride at pH level of 5-6 and electrochemical deposition temperature of around 70°C. The study was also conducted at a very low stirring rate with different applied potentials. Applied potential was one of the crucial aspects in the formation of self-organized ZnO nanorod film via control of the field-assisted dissolution and field-assisted deposition rates during the electrochemical deposition process. Interestingly, low applied potentials of 1 V during electrochemical deposition produced a high aspect ratio and density of self-organized ZnO nanorod distribution on the Zn substrate with an average diameter and length of ~37.9 nm and ~249.5 nm, respectively. Therefore, it exhibited a high photocurrent density that reached 17.8 mA/cm2 under ultraviolet illumination and 12.94 mA/cm2 under visible illumination. This behaviour was attributed to the faster transport of photogenerated electron/hole pairs in the nanorod’s one-dimensional wall surface, which prevented backward reactions and further reduced the number of recombination centres.

  7. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Juan [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31, Perú (Peru); Onna, Diego [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Sánchez, Luis [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31, Perú (Peru); Marchi, M. Claudia [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Centro de Microscopias Avanzadas, FCEyN-Universidad ed Buenos Aires, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina); Candal, Roberto, E-mail: rjcandal@gmail.com [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); ECyT, 3iA, Universidad Nacional de San Martín, Martín de Irigoyen No 3100 (1650), San Martín, Pcia de Buenos Aires (Argentina); Ponce, Silvia [Universidad de Lima, Av. Javier Prado Este s/n, Monterrico, Lima 33, Perú (Peru); Bilmes, Sara A. [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina)

    2013-08-15

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  8. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    International Nuclear Information System (INIS)

    Rodríguez, Juan; Onna, Diego; Sánchez, Luis; Marchi, M. Claudia; Candal, Roberto; Ponce, Silvia; Bilmes, Sara A.

    2013-01-01

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  9. Synthesis of Fe-Doped ZnO Nanorods by Rapid Mixing Hydrothermal Method and Its Application for High Performance UV Photodetector

    Directory of Open Access Journals (Sweden)

    Chan Oeurn Chey

    2014-01-01

    Full Text Available We have successfully synthesized Fe-doped ZnO nanorods by a new and simple method in which the adopted approach is by using ammonia as a continuous source of OH- for hydrolysis instead of hexamethylenetetramine (HMT. The energy dispersive X-ray (EDX spectra revealed that the Fe peaks were presented in the grown Fe-doped ZnO nanorods samples and the X-ray photoelectron spectroscopy (XPS results suggested that Fe3+ is incorporated into the ZnO lattice. Structural characterization indicated that the Fe-doped ZnO nanorods grow along the c-axis with a hexagonal wurtzite structure and have single crystalline nature without any secondary phases or clusters of FeO or Fe3O4 observed in the samples. The Fe-doped ZnO nanorods showed room temperature (300 K ferromagnetic magnetization versus field (M-H hysteresis and the magnetization increases from 2.5 μemu to 9.1 μemu for Zn0.99Fe0.01O and Zn0.95Fe0.05O, respectively. Moreover, the fabricated Au/Fe-doped ZnO Schottky diode based UV photodetector achieved 2.33 A/W of responsivity and 5 s of time response. Compared to other Au/ZnO nanorods Schottky devices, the presented responsivity is an improvement by a factor of 3.9.

  10. Modulating the size of ZnO nanorods on SiO2 substrates by incorporating reduced graphene oxide into the seed layer solution

    Directory of Open Access Journals (Sweden)

    Tzu-Yi Yu

    2017-06-01

    Full Text Available In this research, reduced graphene oxide was incorporated into the ZnO seed layer to modulate the rod diameter of ZnO nanorods (NRs during solgel/hydrothermal growth. To characterize the reduced graphene oxide incorporated ZnO NRs, multiple material analysis techniques including field-emission scanning electron microscopy, surface contact angle measurements, X-ray diffraction, and photoluminescence were used to explore distinct properties of these size modulatable NRs. Results indicate ZnO NRs with smaller diameters could be observed with more reduced graphene oxide added into the ZnO seed layer. Furthermore, better crystallinity, higher hydrophobicity and lower defect concentration could be obtained with more amount of reduced graphene oxide added into the ZnO seed layer. The modulatable reduced graphene oxide-incorporated ZnO NRs growth is promising for future ZnO NRs based nanodevice applications.

  11. Cu2O-tipped ZnO nanorods with enhanced photoelectrochemical performance for CO2 photoreduction

    Science.gov (United States)

    Iqbal, Muzaffar; Wang, Yanjie; Hu, Haifeng; He, Meng; Hassan Shah, Aamir; Lin, Lin; Li, Pan; Shao, Kunjuan; Reda Woldu, Abebe; He, Tao

    2018-06-01

    The design of Cu2O-tipped ZnO nanorods is proposed here aiming at enhanced photoelectrochemical properties. The tip-selective deposition of Cu2O is confirmed by scanning transmission electron microscopy (STEM). The photoinduced charge behavior like charge generation, separation and transport has been thoroughly studied by UV-vis absorption analysis and different photoelectrochemical characterizations, including transient photocurrent, incident photon-to-current efficiency (IPCE), electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS), and Mott-Schottky measurements. The photoelectrochemical characterizations clearly indicate that ZnO/Cu2O structures exhibit much higher performance than pristine ZnO, due to the formation of p-n junction, as well as the tip selective growth of Cu2O on ZnO. Photocatalytic CO2 reduction in aqueous solution under UV-visible light illumination shows that CO is the main product, and with the increase of the Cu2O content in the heterostructure, the CO yield increases. This work shows that Cu2O-tipped ZnO nanorods possess improved behavior of charge generation, separation and transport, which may work as a potential candidate for photocatalytic CO2 reduction.

  12. Falling Leaves Inspired ZnO Nanorods-Nanoslices Hierarchical Structure for Implant Surface Modification with Two Stage Releasing Features.

    Science.gov (United States)

    Liao, Hang; Miao, Xinxin; Ye, Jing; Wu, Tianlong; Deng, Zhongbo; Li, Chen; Jia, Jingyu; Cheng, Xigao; Wang, Xiaolei

    2017-04-19

    Inspired from falling leaves, ZnO nanorods-nanoslices hierarchical structure (NHS) was constructed to modify the surfaces of two widely used implant materials: titanium (Ti) and tantalum (Ta), respectively. By which means, two-stage release of antibacterial active substances were realized to address the clinical importance of long-term broad-spectrum antibacterial activity. At early stages (within 48 h), the NHS exhibited a rapid releasing to kill the bacteria around the implant immediately. At a second stage (over 2 weeks), the NHS exhibited a slow releasing to realize long-term inhibition. The excellent antibacterial activity of ZnO NHS was confirmed once again by animal test in vivo. According to the subsequent experiments, the ZnO NHS coating exhibited the great advantage of high efficiency, low toxicity, and long-term durability, which could be a feasible manner to prevent the abuse of antibiotics on implant-related surgery.

  13. Influence of ZnO seed layer precursor molar ratio on the density of interface defects in low temperature aqueous chemically synthesized ZnO nanorods/GaN light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Alnoor, Hatim, E-mail: hatim.alnoor@liu.se; Iandolo, Donata; Willander, Magnus; Nur, Omer [Department of Science and Technology (ITN), Linköping University, SE-601 74 Norrköping (Sweden); Pozina, Galia; Khranovskyy, Volodymyr; Liu, Xianjie [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-583 81 Linköping (Sweden)

    2016-04-28

    Low temperature aqueous chemical synthesis (LT-ACS) of zinc oxide (ZnO) nanorods (NRs) has been attracting considerable research interest due to its great potential in the development of light-emitting diodes (LEDs). The influence of the molar ratio of the zinc acetate (ZnAc): KOH as a ZnO seed layer precursor on the density of interface defects and hence the presence of non-radiative recombination centers in LT-ACS of ZnO NRs/GaN LEDs has been systematically investigated. The material quality of the as-prepared seed layer as quantitatively deduced by the X-ray photoelectron spectroscopy is found to be influenced by the molar ratio. It is revealed by spatially resolved cathodoluminescence that the seed layer molar ratio plays a significant role in the formation and the density of defects at the n-ZnO NRs/p-GaN heterostructure interface. Consequently, LED devices processed using ZnO NRs synthesized with molar ratio of 1:5 M exhibit stronger yellow emission (∼575 nm) compared to those based on 1:1 and 1:3 M ratios as measured by the electroluminescence. Furthermore, seed layer molar ratio shows a quantitative dependence of the non-radiative defect densities as deduced from light-output current characteristics analysis. These results have implications on the development of high-efficiency ZnO-based LEDs and may also be helpful in understanding the effects of the ZnO seed layer on defect-related non-radiative recombination.

  14. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    International Nuclear Information System (INIS)

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Salleh, Muhamad Mat

    2013-01-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification. (paper)

  15. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    Science.gov (United States)

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Mat Salleh, Muhamad

    2013-04-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification.

  16. A novel fabrication methodology for sulfur-doped ZnO nanorods as an active photoanode for improved water oxidation in visible-light regime

    Science.gov (United States)

    Khan, A.; Ahmed, M. I.; Adam, A.; Azad, A.-M.; Qamar, M.

    2017-02-01

    Incorporation of foreign moiety in the lattice of semiconductors significantly alters their optoelectronic behavior and opens a plethora of new applications. In this paper, we report the synthesis of sulfur-doped zinc oxide (S-doped ZnO) nanorods by reacting ZnO nanorods with diammonium sulfide in vapor phase. Microscopic investigation revealed that the morphological features, such as, the length (2-4 μm) and width (100-250 nm) of the original hexagonal ZnO nanorods remained intact post-sulfidation. X-ray photoelectron spectroscopy analysis of the sulfide sample confirmed the incorporation of sulfur into ZnO lattice. The optical measurements suggested the extension of absorption threshold into visible region upon sulfidation. Photoelectrochemical (PEC) activities of pure and S-doped ZnO nanorods were compared for water oxidation in visible light (λ > 420 nm), which showed several-fold increment in the performance of S-doped ZnO sample; the observed amelioration in the PEC activity was rationalized in terms of preferred visible light absorption and low resistance of sulfide sample, as evidenced by optical and electrochemical impedance spectroscopy.

  17. Temperature-dependent Photoluminescence of Boron-doped ZnO Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soaram; Park, Hyunggil; Nam, Giwoong; Yoon, Hyunsik; Leem, Jaeyoung [Inje Univ., Gimhae (Korea, Republic of); Kim, Jong Su; Lee, Sangheon [Yeungnam Univ., Gyeongsan (Korea, Republic of); Kim, Jin Soo [Chonbuk National Univ., Jeonju (Korea, Republic of); Son, Jeongsik [Kyungwoon Univ., Gumi (Korea, Republic of)

    2013-11-15

    Boron-doped ZnO (BZO) nanorods were grown on quartz substrates using hydrothermal synthesis, and the temperature-dependence of their photoluminescence (PL) was measured in order to investigate the origins of their PL properties. In the UV range, near-band-edge emission (NBE) was observed from 3.1 to 3.4 eV; this was attributed to various transitions including recombination of free excitons and their longitudinal optical (LO) phonon replicas, and donor-acceptor pair (DAP) recombination, depending on the local lattice configuration and the presence of defects. At a temperature of 12 K, the NBE produces seven peaks at 3.386, 3.368, 3.337, 3.296, 3.258, 3.184, and 3.106 eV. These peaks are, respectively, assigned to free excitons (FX), neutral-donor bound excitons (D{sup o}X), and the first LO phonon replicas of D{sup o}X, DAP, DAP-1LO, DAP-2LO, and DAP-3LO. The peak position of the FX and DAP were also fitted to Varshni's empirical formula for the variation in the band gap energy with temperature. The activation energy of FX was about ∼70 meV, while that of DAP was about ∼38 meV. We also discuss the low temperature PL near 2.251 eV, related to structural defects.

  18. Cu{sub 2}ZnSn(S,Se){sub 4} from Cu{sub x}SnS{sub y} nanoparticle precursors on ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kavalakkatt, Jaison, E-mail: jai.k@web.de [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universitaet Berlin, Berlin (Germany); Lin, Xianzhong; Kornhuber, Kai [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Kusch, Patryk [Freie Universitaet Berlin, Berlin (Germany); Ennaoui, Ahmed [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Reich, Stephanie [Freie Universitaet Berlin, Berlin (Germany); Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universitaet Berlin, Berlin (Germany)

    2013-05-01

    Solar cells with Cu{sub 2}ZnSnS{sub 4} absorber thin films have a potential for high energy conversion efficiencies with earth-abundant and non-toxic elements. In this work the formation of CZTSSe from Cu{sub x}SnS{sub y} nanoparticles (NPs) deposited on ZnO nanorod (NR) arrays as precursors for zinc is investigated. The NPs are prepared using a chemical route and are dispersed in toluene. The ZnO NRs are grown on fluorine doped SnO{sub 2} coated glass substrates by electro deposition method. A series of samples are annealed at different temperatures between 300 °C and 550 °C in selenium containing argon atmosphere. To investigate the products of the reaction between the precursors the series is analyzed by means of X-ray diffraction (XRD) and Raman spectroscopy. The morphology is recorded by scanning electron microscopy (SEM) images of broken cross sections. The XRD measurements and the SEM images show the disappearing of ZnO NRs with increasing annealing temperature. Simultaneously the XRD and Raman measurements show the formation of CZTSSe. The formation of secondary phases and the optimum conditions for the preparation of CZTSSe is discussed. - Highlights: ► Cu{sub x}SnS{sub y} nanoparticles are deposited on ZnO nanorod arrays. ► Samples are annealed at different temperatures (300–550 °C) in Se/Ar-atmosphere. ► Raman spectroscopy, X-ray diffraction and electron microscopy are performed. ► ZnO disappears with increasing annealing temperature. ► With increasing temperature Cu{sub x}SnS{sub y} and ZnO form Cu{sub 2}ZnSn(S,Se){sub 4}.

  19. A comparative study of pure and copper (Cu)-doped ZnO nanorods for antibacterial and photocatalytic applications with their mechanism of action

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, Tamanna [Amity University, Uttar Pradesh, Amity Institute of Microbial Technology (India); Khanuja, Manika, E-mail: manikakhanuja@gmail.com; Sharma, R.; Patel, S.; Reddy, M. R.; Anand, S. [Amity University, Uttar Pradesh, Amity Institute of Nanotechnology (India); Varma, A. [Amity University, Uttar Pradesh, Amity Institute of Microbial Technology (India)

    2015-07-15

    The present study reports the synthesis of pure and Cu-doped ZnO nanorods for antibacterial and photocatalytic applications. The samples were synthesized by simple, low cost mechanical-assisted thermal decomposition process. The synthesized materials were characterized by scanning electron microscopy, UV–Visible spectroscopy, and photoluminescence studies. The antibacterial activity of characterized samples was determined against Gram-positive bacteria such as Staphylococcus aureus and Streptococcus pyogenes and Gram-negative bacteria such as Escherichia coli using shake flask method with respect to time. The significant antibacterial activity was perceived from scanning electron micrographs that clearly revealed bacterial cell lysis resulting in the release of cytoplasmic content followed by cell death. The degradation of methylene blue was used as a model organic dye for photocatalytic activity. The present study demonstrates the superior photocatalytic and antibacterial activity of Cu-doped ZnO nanorods with respect to pure ZnO nanorods.

  20. Bias-polarity-dependent UV/visible transferable electroluminescence from ZnO nanorod array LED with graphene oxide electrode supporting layer

    Science.gov (United States)

    Liu, Weizhen; Wang, Wei; Xu, Haiyang; Li, Xinghua; Yang, Liu; Ma, Jiangang; Liu, Yichun

    2015-09-01

    A simple top electrode preparation process, employing continuous graphene oxide films as electrode supporting layers, was adopted to fabricate a ZnO nanorod array/p-GaN heterojunction LED. The achieved LED demonstrated different electroluminescence behaviors under forward and reverse biases: a yellow-red emission band was observed under forward bias, whereas a blue-UV emission peak was obtained under reverse bias. Electroluminescence spectra under different currents and temperatures, as well as heterojunction energy-band alignments, reveal that the yellow-red emission under forward bias originates from recombinations related to heterointerface defects, whereas the blue-UV electroluminescence under reverse bias is ascribed to transitions from near-band-edge and Mg-acceptor levels in p-GaN.

  1. UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction prepared by a simple process

    International Nuclear Information System (INIS)

    Echresh, Ahmad; Chey, Chan Oeurn; Zargar Shoushtari, Morteza; Khranovskyy, Volodymyr; Nur, Omer; Willander, Magnus

    2015-01-01

    Highlights: • The p-NiO/n-ZnO heterojunction showed an obvious rectifying behavior and the response of the diode was excellent in generating photocurrent upon UV illumination. • Diode electrical performance presented here were superior to those achieved from similar heterojunction prepared by different methods. • The XPS results show that the heterojunction has a type-II band alignment with a valence band offset of 1.50 eV and conduction band offset of 1.83 eV. - Abstract: A UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction was fabricated using a simple two-step fabrication process. The aqueous chemical hydrothermal and thermal evaporation methods were combined to grow the ZnO nanorods and the NiO thin film, respectively. Structural investigation indicated that well aligned ZnO nanorods with hexagonal face having a preferential orientation along the c-axis (0 0 2) have been achieved and that the NiO thin film is covering all the ZnO nanorods. X-ray photoelectron spectroscopy (XPS) was used to investigate the band alignment of the heterojunction and the valence and the conduction band offsets were determined to be 1.50 eV and 1.83 eV, respectively. The current–voltage characteristics of the p-NiO thin film/ZnO nanorods heterojunction showed a clear rectifying behavior under both dark and UV illumination conditions. The response of the heterojunction diode was excellent regarding the photocurrent generation. Although other similar heterojunction diodes demonstrated lower threshold voltage, the rectification ratio and the sensitivity of the fabricated diode were superior in comparison to other similar heterojunctions reported recently, implying the vitality of the presented two-step process

  2. A study of the effects of aligned vertically growth time on ZnO nanorods deposited for the first time on Teflon substrate

    Science.gov (United States)

    Farhat, O. F.; Halim, M. M.; Ahmed, Naser M.; Oglat, Ammar A.; Abuelsamen, A. A.; Bououdina, M.; Qaeed, M. A.

    2017-12-01

    In this study, ZnO nanorods (NRs) were well deposited on Teflon substrates (PTFE) via a chemical bath deposition (CBD) method at low temperature. The consequences of growth time (1 h-4 h) on the structural and optical properties of the aligned ZnO (NRs) were investigated through X-ray diffraction, field-emission scanning electron microscopy (FESEM), and photoluminescence (PL) analyses. The results show that the ZnO (NRs) were preferred to grew aligned along the c-axis as hexagonal wurtzite structure as proved by the sharp and strong ZnO (002) peaks of the ZnO (NRs). Irrespective of the growth continuation, FESEM photos confirmed that the ZnO nanorods arrays were fit to be aligned along the c-axis and perpendicular to (PTFE) substrates. The ZnO nanorods that exhibited the sharper stand most intense PL peaks among the sample were grown for 3hs as demonstrated by PL spectra. The device further showed a sensitivity of 4068 to low-power (1.25 mW/cm2) 375 nm light pulses without an external bias. The measurements of photoresponse demonstrated the highly reproducible characteristics of the fabricated UV detector with rapid response and baseline recovery times of 48.05 ms. Thus, this work introduced a simple, low-cost method of fabricating rapid-response, and highly photosensitive UV detectors with zero power consumption on Teflon substrates.

  3. White electroluminescence from ZnO nanorods/p-GaN heterojunction light-emitting diodes under reverse bias

    International Nuclear Information System (INIS)

    Zhang, Lichun; Li, Qingshan; Qu, Chong; Zhang, Zhongjun; Huang, Ruizhi; Zhao, Fengzhou

    2013-01-01

    Heterojunction light-emitting diodes (LEDs) based on arrays of ZnO nanorods were fabricated on p-GaN films by the hydrothermal method. Without any phosphors, white-light electroluminescence (EL) from ZnO nanorods/p-GaN heterojunction LEDs operated at reverse breakdown bias was observed. The EL spectra are composed of an ultraviolet (UV) emission centered at 382 nm, a blue light located at 431 nm and a broadband yellow–green light at around 547 nm, which originated from band-edge emission in ZnO, the Mg acceptor levels in p-GaN and the deep-level states near the ZnO/GaN interface, respectively. The chromaticity coordinates of EL spectrum are very close to the (0.333, 0.333) of standard white light. The origin of these emissions has been discussed and the tunneling effect in the interface is probably the mechanism to explain EL emission. (paper)

  4. Different defect levels configurations between double layers of nanorods and film in ZnO grown on c-Al2O3 by MOCVD

    International Nuclear Information System (INIS)

    Wu, Bin; Zhang, Yuantao; Shi, Zhifeng; Li, Xiang; Cui, Xijun; Zhuang, Shiwei; Zhang, Baolin; Du, Guotong

    2014-01-01

    Epitaxial ZnO structures with inherent two layers of nanorods layer on film layer were fabricated on c-Al 2 O 3 by metal-organic chemical vapor deposition (MOCVD) and studied by photoluminescence. Specially, photoluminescence spectra for the film layer were obtained by rendering the excitation from the substrate side. Different defect levels configurations between nanorods and film were revealed. Zinc vacancies tend to form in top nanorods layer, whereas abundant zinc–oxygen divacancies accumulate in bottom film layer. An acceptor state with activation energy of ∼200 meV is exclusive to the film layer. The stacking fault related acceptor and Al introduced donor are present in both layers. Besides, two other defect related donors contained in the nanorods layer perhaps also exist within the film layer. - Highlights: • Inherent double layer ZnO of nanorods on film layer were studied by PL. • V Zn tend to form in the nanorods layer, and V ZnO accumulate in the film layer. • An acceptor with activation energy of ∼200 meV is exclusive to the film layer. • Pure NBE emission without DLE in RT PL spectrum does not mean good crystallinity

  5. WO{sub 3} nanorods prepared by low-temperature seeded growth hydrothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@eng.usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2014-03-05

    Highlights: • WO{sub 3} nanorods with 5–10 nm diameter were grown directly on seeded tungsten foil. • WO{sub 3} nanorods were successfully grown at low temperature of 80 °C. • WO{sub 3} nanorods were grown on the entire surface of the seed layer after 24 h. • Annealed nanorods showed better electrochromic properties than as-made nanorods. -- Abstract: This work describes the first tungsten oxide (WO{sub 3}) nanorods hydrothermally grown on W foil. WO{sub 3} nanorods were successfully grown at low hydrothermal temperature of 80 °C by seeded growth hydrothermal reaction. The seed layer was prepared by thermally oxidized the W foil at 400 °C for 0.5 h. This work discusses the effect of hydrothermal reaction and annealing period on the morphological, structural, and electrochromic properties of WO{sub 3} nanorods. Various hydrothermal reaction periods (8–24 h) were studied. Monoclinic WO{sub 3} nanorods with 5–10 nm diameter were obtained after hydrothermal reaction for 24 h. These 24 h WO{sub 3} nanorods were also annealed at 400 °C with varying dwelling periods (0.5–4 h). Electrochromic properties of WO{sub 3} nanorods in an acidic electrolyte were analyzed using cyclic voltammetry and UV–vis spectrophotometry. WO{sub 3} nanorods annealed at 400 °C for 1 h showed the highest charge capacity and the largest optical contrast among the 24 h WO{sub 3} films. The sample also showed good cycling stability without significant degradation. Based on the results, the reaction mechanism of WO{sub 3} nanorod formation on W foil was proposed.

  6. Octadecyltrimethoxysilane functionalized ZnO nanorods as a novel coating for solid-phase microextraction with strong hydrophobic surface.

    Science.gov (United States)

    Zeng, Jingbin; Liu, Haihong; Chen, Jinmei; Huang, Jianli; Yu, Jianfeng; Wang, Yiru; Chen, Xi

    2012-09-21

    In this paper, we have, for the first time, proposed an approach by combining self-assembled monolayers (SAMs) and nanomaterials (NMs) for the preparation of novel solid-phase microextraction (SPME) coatings. The self-assembly of octadecyltrimethoxysilane (OTMS) on the surface of ZnO nanorods (ZNRs) was selected as a model system to demonstrate the feasibility of this approach. The functionalization of OTMS on the surface of ZNRs was characterized and confirmed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The OTMS-ZNRs coated fiber exhibited stronger hydrophobicity after functionalization, and its extraction efficiency for non-polar benzene homologues was increased by a factor of 1.5-3.6 when compared to a ZNRs fiber with almost identical thickness and façade. In contrast, the extraction efficiency of the OTMS-ZNRs coated fiber for polar aldehydes was 1.6-4.0-fold lower than that of the ZNRs coated fiber, further indicating its enhanced surface hydrophobicity. The OTMS-ZNRs coated fiber revealed a much higher capacity upon increasing the OTMS layer thickness to 5 μm, leading to a factor of 12.0-13.4 and 1.8-2.5 increase in extraction efficiency for the benzene homologues relative to a ZNRs coated fiber and a commercial PDMS fiber, respectively. The developed HS-SPME-GC method using the OTMS-ZNRs coated fiber was successfully applied to the determination of the benzene homologues in limnetic water samples with recovery ranging from 83 to 113% and relative standard deviations (RSDs) of less than 8%.

  7. Catalyst-free vapor-phase transport growth of vertically aligned ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mofor, A.C.; Bakin, A.S.; Elshaer, A.; Waag, A. [Inst. of Semiconductor Technology, Technical Univ. Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Inst. of Applied Physics, Technical Univ. Braunschweig (Germany); Bertram, F.; Christen, J. [Dept. of Solid State Physics, Univ. of Magdeburg (Germany)

    2006-03-15

    ZnO nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Fabrication methods, especially for nanorods have been based mostly on catalyst-assisted growth methods that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on the growth of ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3} using purely elemental sources, without catalysis and at relatively low temperatures and growth pressure in a specially designed vapor-phase transport system. ZnO nanorods with widths of 80-900 nm and lengths of 4-12 {mu}m were obtained. Nanorod concentrations of up to 10{sup 9} cm{sup -2} with homogenous luminescence and high purity were noted. (orig.)

  8. Effect of Sn doping on structural, mechanical, optical and electrical properties of ZnO nanoarrays prepared by sol-gel and hydrothermal process

    Science.gov (United States)

    Agarwal, Manish Baboo; Sharma, Akash; Malaidurai, M.; Thangavel, R.

    2018-05-01

    Undoped and Sn doped Zinc oxide nanorods were prepared by two step process: initially growth of seed layers by sol-gel spin coating technique and then zinc oxide nanorods by hydrothermal process using the precursors zinc nitrate hexahydrate, hexamine and tin chloride. The effects on the electrical, optical, mechanical and structural properties for various Sn concentrations were studied. The crystalline phase determination from X-ray diffraction (XRD) confirms that Sn doped ZnO nanorods have hexagonal wurtzite structure. The variations of stress and strain with different doping concentration of Sn in ZnO nanorods were studied. The doping effect on electrical properties and optical bandgap is estimated by current voltage characteristics and absorbance spectra respectively. The surface morphology was studied with field emission scanning electron microscope (FESEM), which shows that the formation of hexagonal nanorods arrays with increasing Sn concentration. The calculated value of Young's modulus of elasticity (Y) for all the samples remains same. These results can be used in optoelectronic devices.

  9. 16.1% Efficient Hysteresis-Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays

    KAUST Repository

    Mahmood, Khalid

    2015-06-01

    Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low-temperature solution-processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density, and substantially reduced work function than conventional ZnO NRs. These features synergistically result in hysteresis-free, scan-independent, and stabilized devices with an efficiency of 16.1%. Electron-rich, nitrogen-doped ZnO (N:ZnO) NR-based electron transporting materials (ETMs) with enhanced electron mobility produced using ammonium acetate show consistently higher efficiencies by one to three power points than undoped ZnO NRs. Additionally, the preferential electrostatic interaction between the -nonpolar facets of N:ZnO and the conjugated polyelectrolyte polyethylenimine (PEI) has been relied on to promote the hydrothermal growth of high aspect ratio NR arrays and substantially improve the infiltration of the perovskite light absorber into the ETM. Using the same interactions, a conformal PEI coating on the electron-rich high aspect ratio N:ZnO NR arrays is -successfully applied, resulting in a favorable work function shift and altogether leading to the significant boost in efficiency from <10% up to >16%. These results largely surpass the state-of-the-art PCE of ZnO-based perovskite solar cells and highlight the benefits of synergistically combining mesoscale control with doping and surface modification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Construction of 3D Arrays of Cylindrically Hierarchical Structures with ZnO Nanorods Hydrothermally Synthesized on Optical Fiber Cores

    Directory of Open Access Journals (Sweden)

    Weixuan Jing

    2014-01-01

    Full Text Available With ZnO nanorods hydrothermally synthesized on manually assembled arrays of optical fiber cores, 3D arrays of ZnO nanorod-based cylindrically hierarchical structures with nominal pitch 250 μm or 375 μm were constructed. Based on micrographs of scanning electron microscopy and image processing operators of MATLAB software, the 3D arrays of cylindrically hierarchical structures were quantitatively characterized. The values of the actual diameters, the actual pitches, and the parallelism errors suggest that the process capability of the manual assembling is sufficient and the quality of the 3D arrays of cylindrically hierarchical structures is acceptable. The values of the characteristic parameters such as roughness, skewness, kurtosis, correlation length, and power spectrum density show that the surface morphologies of the cylindrically hierarchical structures not only were affected significantly by Zn2+ concentration of the growth solution but also were anisotropic due to different curvature radii of the optical fiber core at side and front view.

  11. Voids, nanochannels and formation of nanotubes with mobile Sn fillings in Sn doped ZnO nanorods

    International Nuclear Information System (INIS)

    Ortega, Y; Dieker, Ch; Jaeger, W; Piqueras, J; Fernandez, P

    2010-01-01

    ZnO nanorods containing different hollow structures have been grown by a thermal evaporation-deposition method with a mixture of ZnS and SnO 2 powders as precursor. Transmission electron microscopy shows rods with rows of voids as well as rods with empty channels along the growth axis. The presence of Sn nanoprecipitates associated with the empty regions indicates, in addition, that these are generated by diffusion processes during growth, probably due to an inhomogeneous distribution of Sn. The mechanism of forming voids and precipitates appears to be based on diffusion processes similar to the Kirkendall effect, which can lead to void formation at interfaces of bulk materials or in core-shell nanostructures. In some cases the nanorods are ZnO tubes partially filled with Sn that has been found to melt and expand by heating the nanotubes under the microscope electron beam. Such metal-semiconductor nanostructures have potential applications as thermal nanosensors or as electrical nanocomponents.

  12. RETRACTED: Growth behavior and microstructure evolution of ZnO nanorods grown on Si in aqueous solution

    Science.gov (United States)

    Liou, Sz-Chian; Hsiao, Chi-Sheng; Chen, San-Yuan

    2005-02-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal. This article has been retracted at the request of the Editor-in-Chief. Two papers published in the Journal of Crystal Growth are being retracted due to a case of misrepresentation and reuse of data. A reader of the Journal has brought to our attention the reuse of data within two published papers: Growth behavior and microstructure evolution of ZnO nanorods grown on Si in aqueous solution, Sz-Chian Liou, Chi-Sheng Hsiao, San-Yuan Chen, Journal of Crystal Growth 274 (2005) 438-446. Nucleation and growth behavior of well-aligned ZnO nanorods on organic substrates in aqueous solutions, Chin-Ching Lin, San-Yuan Chen, and Syh-Yuh Cheng, Journal of Crystal Growth 283 (2005) 141-146. In these papers the same transmission electron micrograph was used to describe two different experimental situations and results bringing into question the content of these papers. The reuse of data without proper attribution is not acceptable within the scientific publishing community. In the present case, this is compounded by the attribution of the micrograph to a different experimental situation and drawing, as a result, new conclusions from data obtained from different samples. Such behavior undermines the integrity of the scientific publishing endeavor and is not acceptable. The authors are responsible for the content of their papers.

  13. Preparation and characterization of bionanocomposite film based ontapioca starch/bovine gelatin/nanorod zinc oxide

    DEFF Research Database (Denmark)

    Mehdi Marvizadeh, Mohammad; Oladzadabbasabadi, Nazila; Mohammadi Nafchi, Abdorreza

    2017-01-01

    , as well as the barrier properties of bionanocomposite films were investigated. X-ray diffraction analysis showed that the bionanocomposite film incorporated with ZnOsingle bondN at a concentration of 3.5% w/w exhibited high intensity peaks compared with control samples. Results of UV–vis spectra analysis......To exploring a nano-packaging materials for using as coating or edible films, tapioca starch/gelatin/nanorod ZnO (ZnOsingle bondN) bionanocomposites were prepared via solution casting technique. The effects of nanofiller addition on the mechanical, physicochemical, and crystalline structures...... showed that incorporation of ZnOsingle bondN into the films can absorb the whole UV light. Tensile strength of the films was increased from 14 to 18 MPa whereas elongation at breaks decreased from 18 to 8 percent and oxygen permeability decreased from 151.03 to 91.52 cm3 μm/(m2–day) by incorporation of 3...

  14. Functionalized vertically aligned ZnO nanorods for application in electrolyte-insulator-semiconductor based pH sensors and label-free immuno-sensors

    International Nuclear Information System (INIS)

    Kumar, Narendra; Senapati, Sujata; Kumar, Jitendra; Panda, Siddhartha; Kumar, Satyendra

    2016-01-01

    Vertically aligned ZnO nanorods were grown on a SiO 2 /Si surface by optimization of the temperature and atmosphere for annealing of the seed. The seed layer annealed at 500 °C in vacuum provided well separated and uniform seeds which also provided the best condition to get densely packed, uniformly distributed, and vertically aligned nanorods. These nanorods grown on the substrates were used to fabricate electrolyte-insulator-semiconductor (EIS) devices for pH sensing. Etching of ZnO at acidic pH prevents the direct use of nanorods for pH sensing. Therefore, the nanorods functionalised with 3-aminopropyltriethoxysilane (APTES) were utilized for pH sensing and showed the pH sensitivity of 50.1 mV/pH. APTES is also known to be used as a linker to immobilize biomolecules (such as antibodies). The EIS device with APTES functionalized nanorods was used for the label free detection of prostate-specific antigen (PSA). Finally, voltage shifts of 23 mV and 35 mV were observed with PSA concentrations of 1 ng/ml and 100 ng/ml, respectively. (paper)

  15. Room temperature ferromagnetism in ZnO prepared by microemulsion

    Directory of Open Access Journals (Sweden)

    Qingyu Xu

    2011-09-01

    Full Text Available Clear room temperature ferromagnetism has been observed in ZnO powders prepared by microemulsion. The O vacancy (VO clusters mediated by the VO with one electron (F center contributed to the ferromagnetism, while the isolated F centers contributed to the low temperature paramagnetism. Annealing in H2 incorporated interstitial H (Hi in ZnO, and removed the isolated F centers, leading to the suppression of the paramagnetism. The ferromagnetism has been considered to originate from the VO clusters mediated by the Hi, leading to the enhancement of the coercivity. The ferromagnetism disappeared after annealing in air due to the reduction of Hi.

  16. Facile formation of ZIF-8 thin films on ZnO nanorods

    NARCIS (Netherlands)

    Al-Kutubi, H.; Dikhtiarenko, A.; Zafarani, H.R.; Sudhölter, E.J.R.; Gascon, J.; Rassaei, L.

    2015-01-01

    In this work, thin films of the well-known metal–organic framework ZIF-8 were formed on zinc oxide nanorods through the reaction with 2-methyl-imidazole solution (Hmim). Deposition of a thin film of the linker solution allows the underlying zinc oxide nanorod morphology to be preserved, resulting in

  17. Selective tuning of enhancement in near band edge emission in hydrothermally grown ZnO nanorods coated with gold

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, Tejendra, E-mail: phd12110211@iiti.ac.in [Molecular and Nanoelectronics Research Group (MNRG), Department of Electrical Engineering, IIT Indore, Indore, Madhya Pradesh (India); Palani, I.A., E-mail: palaniia@iiti.ac.in [Mechatronics and Instrumentation Lab, Department of Mechanical Engineering, IIT Indore, Indore, Madhya Pradesh (India); Centre of Material Science and Engineering, IIT Indore, Indore, Madhya Pradesh (India); Singh, Vipul, E-mail: vipul@iiti.ac.in [Molecular and Nanoelectronics Research Group (MNRG), Department of Electrical Engineering, IIT Indore, Indore, Madhya Pradesh (India); Centre of Material Science and Engineering, IIT Indore, Indore, Madhya Pradesh (India)

    2016-02-15

    The room-temperature photoluminescence (PL) spectra of hydrothermally grown ZnO nanorods (NRs) coated with Au using dc sputtering and thermal evaporation were systematically investigated. Au coated (via dc sputtering) ZnO NRs were found to exhibit very large near band edge emission enhancement, on the contrary Au coated (via thermal evaporation) ZnO NRs showed suppression in the near band edge emission peak. These observed results were further confirmed by excitation intensity (EI) dependent PL spectra of different samples. Further using Raman spectra it has been observed that the longitudinal optical (LO) phonons exhibit an enhancement and a weakening by the Au coatings, using dc sputtering and thermal evaporation respectively. Finally by controlling the concentration of KMnO{sub 4} as an additive during the hydrothermal growth, selective tuning in the defect density was carried out, which was later utilized to probe the effect of defect density of the Au–ZnO plasmonic coupling. Moreover, our results strongly suggest that the EI dependent PL has a strong dependence on the metal coating technique. The findings presented in this article clearly indicate the dependence of Au–ZnO plasmonic coupling on the overall defect density and the process of Au deposition.

  18. Assessment of the out-plane and in-plane ordering of high quality ZnO nanorods by X-ray multiple diffraction

    International Nuclear Information System (INIS)

    Martínez-Tomás, M.C.; Montenegro, D.N.; Agouram, S.; Sallet, V.; Muñoz-Sanjosé, V.

    2013-01-01

    ZnO nanorods grown on buffered and non buffered sapphire substrates have been investigated by X-ray multiple diffraction using Renninger scans of the ZnO(0001) and ZnO(0003) forbidden reflections. In this technique the diffracted X-ray beam is simultaneously diffracted by several sets of planes, providing information on the broadening in different directions, as well as from nanorods, and from the layer on which they grow. The intensities and angular widths of peaks obtained by azimuthal and omega scans have been analyzed, making a direct comparison with conventional measurements of the full width at half-maximum of symmetric and asymmetric reflections. The analysis leads to establish that the peaks of the Renninger scan are highly sensitive to structural characteristics, providing information related with both the out-plane and in-plane ordering of nanostructured samples with a single scan. - Highlights: ► Structural characteristics of ZnO nanorods have been analyzed by X-ray multiple diffraction. ► X-ray multiple diffraction can provide mosaic structure characteristics from a single scan. ► Peaks of Renninger scan result to be very sensitive to structural characteristics. ► X-ray multiple diffraction can be an alternative analysis method to X-ray diffraction

  19. Assessment of the out-plane and in-plane ordering of high quality ZnO nanorods by X-ray multiple diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Tomás, M.C., E-mail: Carmen.Martinez-tomas@uv.es [Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot (Spain); Montenegro, D.N.; Agouram, S. [Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot (Spain); Sallet, V. [Groupe d' Etude de la Matière Condensée (GEMAC), CNRS-Université de Versailles St-Quentin, 45 avenue des Etats-Unis, 78035 Versailles Cedex (France); Muñoz-Sanjosé, V. [Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, Dr. Moliner 50, 46100 Burjassot (Spain)

    2013-08-31

    ZnO nanorods grown on buffered and non buffered sapphire substrates have been investigated by X-ray multiple diffraction using Renninger scans of the ZnO(0001) and ZnO(0003) forbidden reflections. In this technique the diffracted X-ray beam is simultaneously diffracted by several sets of planes, providing information on the broadening in different directions, as well as from nanorods, and from the layer on which they grow. The intensities and angular widths of peaks obtained by azimuthal and omega scans have been analyzed, making a direct comparison with conventional measurements of the full width at half-maximum of symmetric and asymmetric reflections. The analysis leads to establish that the peaks of the Renninger scan are highly sensitive to structural characteristics, providing information related with both the out-plane and in-plane ordering of nanostructured samples with a single scan. - Highlights: ► Structural characteristics of ZnO nanorods have been analyzed by X-ray multiple diffraction. ► X-ray multiple diffraction can provide mosaic structure characteristics from a single scan. ► Peaks of Renninger scan result to be very sensitive to structural characteristics. ► X-ray multiple diffraction can be an alternative analysis method to X-ray diffraction.

  20. Low temperature preparation of Ag-doped ZnO nanowire arrays for sensor and light-emitting diode applications

    Science.gov (United States)

    Lupan, O.; Viana, B.; Cretu, V.; Postica, V.; Adelung, R.; Pauporté, T.

    2016-02-01

    Transition metal doped-oxide semiconductor nanostructures are important to achieve enhanced and new properties for advanced applications. We describe the low temperature preparation of ZnO:Ag nanowire/nanorod (NW/NR) arrays by electrodeposition at 90 °C. The NWs have been characterized by SEM, EDX, transmittance and photoluminescence (PL) measurements. The integration of Ag in the crystal is shown. Single nanowire/nanorod of ZnO:Ag was integrated in a nanosensor structure leading to new and enhanced properties. The ultraviolet (UV) response of the nanosensor was investigated at room temperature. Experimental results indicate that ZnO:Ag (0.75 μM) nanosensor possesses faster response/recovery time and better response to UV light than those reported in literature. The sensor structure has been also shown to give a fast response for the hydrogen detection with improved performances compared to pristine ZnO NWs. ZnO:Ag nanowire/nanorod arrays electrochemically grown on p-type GaN single crystal layer is also shown to act as light emitter in LED structures. The emission wavelength is red-shifted compared to pristine ZnO NW array. At low Ag concentration a single UV-blue emission is found whereas at higher concentration of dopant the emission is broadened and extends up to the red wavelength range. Our study indicates that high quality ZnO:Ag NW/NR prepared at low temperature by electrodeposition can serve as building nanomaterials for new sensors and light emitting diodes (LEDs) structures with low-power consumption.

  1. The defect passivation effect of hydrogen on the optical properties of solution-grown ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Urgessa, Z.N., E-mail: zelalem.urgessa@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Mbulanga, C.M.; Tankio Djiokap, S.R.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Duvenhage, M.M.; Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)

    2016-01-01

    In this study the effect of annealing environment on both low temperature and room temperature photoluminescence (PL) characteristics of ZnO nanorods, grown in solution, is presented. Particular attention is given to the effect of hydrogen defect passivation and its PL related line. It is shown that, irrespective of annealing ambient, an optimum annealing temperature of 300 °C suppresses the defect related emission and significantly improves the UV emission. By considering the stability of hydrogen impurities, the observed results in the PL spectra are analyzed. There is an observed asymmetric broadening on the low energy side of the bound exciton luminescence in the low temperature annealed samples which is explained by a high concentration of ionized impurities related to hydrogen. This has been attributed primarily to the conversion of hydrogen molecule to substitutional hydrogen on the oxygen site (H{sub O}) as a result of annealing.

  2. The defect passivation effect of hydrogen on the optical properties of solution-grown ZnO nanorods

    International Nuclear Information System (INIS)

    Urgessa, Z.N.; Mbulanga, C.M.; Tankio Djiokap, S.R.; Botha, J.R.; Duvenhage, M.M.; Swart, H.C.

    2016-01-01

    In this study the effect of annealing environment on both low temperature and room temperature photoluminescence (PL) characteristics of ZnO nanorods, grown in solution, is presented. Particular attention is given to the effect of hydrogen defect passivation and its PL related line. It is shown that, irrespective of annealing ambient, an optimum annealing temperature of 300 °C suppresses the defect related emission and significantly improves the UV emission. By considering the stability of hydrogen impurities, the observed results in the PL spectra are analyzed. There is an observed asymmetric broadening on the low energy side of the bound exciton luminescence in the low temperature annealed samples which is explained by a high concentration of ionized impurities related to hydrogen. This has been attributed primarily to the conversion of hydrogen molecule to substitutional hydrogen on the oxygen site (H_O) as a result of annealing.

  3. Fabrication of PbS quantum dots and their applications in solar cells based on ZnO nanorod arrays

    Science.gov (United States)

    Kumar, Dinesh; Chaudhary, Sujeet; Pandya, Dinesh K.

    2018-05-01

    An efficient, inexpensive and large area scalable approach based on sol-gel technique is presented to fabricate quantum dots (QDs) of PbS. Size of the QDs is tuned by the varying the bath concentrations in the range of 50-200 mM. Transmission electron microscopy (TEM) studies confirm the growth of spherically shaped ˜5.6 nm QDs at 50 mM bath concentration. The optical bandgap of the QDs is found to be ˜0.9 eV and corresponds to the size obtained from TEM studies. ZnO/PbS solar cells are fabricated by sensitizing the ZnO nanorods with PbS QDs. The fabricated solar cells demonstrate the highest open circuit voltage ˜200 mV and short circuit current density ˜0.81 µA/cm2.

  4. Influence of the local absorber layer thickness on the performance of ZnO nanorod solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Belaidi, Abdelhak; Dittrich, Thomas; Kieven, David; Tornow, Julian; Schwarzburg, Klaus; Lux-Steiner, Martha [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany)

    2008-08-15

    The local absorber layer thickness (d{sub local}) of solar cells with extremely thin absorber was changed between 10 nm and 70 nm. As a model system, ZnO nanorod arrays (electron conductor) with fixed internal surface area coated with In{sub 2}S{sub 3} (absorber) and impregnated with CuSCN (transparent hole conductor) were applied. The performance of the small area solar cells depended critically on d{sub local}. The highest short circuit current density was reached for the lowest d{sub local}. In contrast, the highest open circuit voltage was obtained for the highest d{sub local}. A maximum energy conversion efficiency of 3.4% at AM1.5 was achieved. Limiting factors are discussed.(copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. RETRACTED: Nucleation and growth behavior of well-aligned ZnO nanorods on organic substrates in aqueous solutions

    Science.gov (United States)

    Lin, Chin-Ching; Chen, San-Yuan; Cheng, Syh-Yuh

    2005-09-01

    Available online : 21 July 2005 This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Two papers published in the Journal of Crystal Growth are being retracted due to a case of misrepresentation and reuse of data. A reader of the Journal has brought to our attention the reuse of data within two published papers: Growth behavior and microstructure evolution of ZnO nanorods grown on Si in aqueous solution, Sz-Chian Liou, Chi-Sheng Hsiao, San-Yuan Chen, Journal of Crystal Growth 274 (2005) 438-446. DOI: 10.1016/j.jcrysgro.2004.10.025 Nucleation and growth behavior of well-aligned ZnO nanorods on organic substrates in aqueous solutions, Chin-Ching Lin, San-Yuan Chen, and Syh-Yuh Cheng, Journal of Crystal Growth 283 (2005) 141-146. DOI: 10.1016/j.jcrysgro.2005.05.065 In these papers the same transmission electron micrograph was used to describe two different experimental situations and results bringing into question the content of these papers. The reuse of data without proper attribution is not acceptable within the scientific publishing community. In the present case, this is compounded by the attribution of the micrograph to a different experimental situation and drawing , as a result, new conclusions from data obtained from different samples. Such behavior undermines the integrity of the scientific publishing endeavor and is not acceptable. The authors are responsible for the content of their papers.

  6. Template-based preparation of free-standing semiconducting polymeric nanorod arrays on conductive substrates.

    Science.gov (United States)

    Haberkorn, Niko; Weber, Stefan A L; Berger, Rüdiger; Theato, Patrick

    2010-06-01

    We describe the synthesis and characterization of a cross-linkable siloxane-derivatized tetraphenylbenzidine (DTMS-TPD), which was used for the fabrication of semiconducting highly ordered nanorod arrays on conductive indium tin oxide or Pt-coated substrates. The stepwise process allow fabricating of macroscopic areas of well-ordered free-standing nanorod arrays, which feature a high resistance against organic solvents, semiconducting properties and a good adhesion to the substrate. Thin films of the TPD derivate with good hole-conducting properties could be prepared by cross-linking and covalently attaching to hydroxylated substrates utilizing an initiator-free thermal curing at 160 degrees C. The nanorod arrays composed of cross-linked DTMS-TPD were fabricated by an anodic aluminum oxide (AAO) template approach. Furthermore, the nanorod arrays were investigated by a recently introduced method allowing to probe local conductivity on fragile structures. It revealed that more than 98% of the nanorods exhibit electrical conductance and consequently feature a good electrical contact to the substrate. The prepared nanorod arrays have the potential to find application in the fabrication of multilayered device architectures for building well-ordered bulk-heterojunction solar cells.

  7. Preparation and photocatalytic property of a novel dumbbell-shaped ZnO microcrystal photocatalyst

    DEFF Research Database (Denmark)

    Sun, Jian-Hui; Dong, Shu-Ying; Wang, Yong-Kui

    2009-01-01

    achieved 68.0%, 99.0% and 98.5%, the TOC removal efficiencies achieved 43.2%, 59.4% and 70.6%, respectively. Compared to commercial ZnO, 16-22% higher TOC removal efficiency was obtained by the dumbbell-shaped ZnO. The results indicated that the prepared dumbbell-shaped ZnO microcrystal photocatalyst...

  8. Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties

    Directory of Open Access Journals (Sweden)

    Sami Elhag

    2016-02-01

    Full Text Available In this paper, we show that the possibility of using polyethylene glycol (EG as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs. EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10−6 M to 10−3 M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

  9. Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties.

    Science.gov (United States)

    Elhag, Sami; Khun, Kimleang; Khranovskyy, Volodymyr; Liu, Xianjie; Willander, Magnus; Nur, Omer

    2016-02-06

    In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10(-6) M to 10(-3) M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

  10. Influence of aspect ratio and surface defect density on hydrothermally grown ZnO nanorods towards amperometric glucose biosensing applications

    Science.gov (United States)

    Shukla, Mayoorika; Pramila; Dixit, Tejendra; Prakash, Rajiv; Palani, I. A.; Singh, Vipul

    2017-11-01

    In this work, hydrothermally grown ZnO Nanorods Array (ZNA) has been synthesized over Platinum (Pt) coated glass substrate, for biosensing applications. In-situ addition of strong oxidizing agent viz KMnO4 during hydrothermal growth was found to have profound effect on the physical properties of ZNA. Glucose oxidase (GOx) was later immobilized over ZNA by means of physical adsorption process. Further influence of varying aspect ratio, enzyme loading and surface defects on amperometric glucose biosensor has been analyzed. Significant variation in biosensor performance was observed by varying the amount of KMnO4 addition during the growth. Moreover, investigations revealed that the suppression of surface defects and aspect ratio variation of the ZNA played key role towards the observed improvement in the biosensor performance, thereby significantly affecting the sensitivity and response time of the fabricated biosensor. Among different biosensors fabricated having varied aspect ratio and surface defect density of ZNA, the best electrode resulted into sensitivity and response time to be 18.7 mA cm-2 M-1 and <5 s respectively. The observed results revealed that apart from high aspect ratio nanostructures and the extent of enzyme loading, surface defect density also hold a key towards ZnO nanostructures based bio-sensing applications.

  11. A versatile light-switchable nanorod memory: Wurtzite ZnO on perovskite SrTiO3

    KAUST Repository

    Kumar, Anup Bera

    2013-04-25

    Integrating materials with distinct lattice symmetries and dimensions is an effective design strategy toward realizing novel devices with unprecedented functionalities, but many challenges remain in synthesis and device design. Here, a heterojunction memory made of wurtzite ZnO nanorods grown on perovskite Nb-doped SrTiO3 (NSTO) is reported, the electronic properties of which can be drastically reconfigured by applying a voltage and light. Despite of the distinct lattice structures of ZnO and NSTO, a consistent nature of single crystallinity is achieved in the heterojunctions via the low-temperature solution-based hydrothermal growth. In addition to a high and persistent photoconductivity, the ZnO/NSTO heterojunction diode can be turned into a versatile light-switchable resistive switching memory with highly tunable ON and OFF states. The reversible modification of the effective interfacial energy barrier in the concurrent electronic and ionic processes most likely gives rise to the high susceptibility of the ZnO/NSTO heterojunction to external electric and optical stimuli. Furthermore, this facile synthesis route is promising to be generalized to other novel functional nanodevices integrating materials with diverse structures and properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of Different HTM Layers and Electrical Parameters on ZnO Nanorod-Based Lead-Free Perovskite Solar Cell for High-Efficiency Performance

    Directory of Open Access Journals (Sweden)

    Farhana Anwar

    2017-01-01

    Full Text Available Simulation has been done using SCAPS-1D to examine the efficiency of CH3NH3SnI3-based solar cells including various HTM layers such as spiro-OMeTAD, Cu2O, and CuSCN. ZnO nanorod array has been considered as an ETM layer. Device parameters such as thickness of the CH3NH3SnI3 layer, defect density of interfaces, density of states, and metal work function were studied. For optimum parameters of all three structures, efficiency of 20.21%, 20.23%, and 18.34% has been achieved for spiro-OMeTAD, Cu2O, and CuSCN, respectively. From the simulations, an alternative lead-free perovskite solar cell is introduced with the CH3NH3SnI3 absorber layer, ZnO nanorod ETM layer, and Cu2O HTM layer.

  13. Bulk Heterojunction Solar Cell Devices Prepared with Composites of Conjugated Polymer and Zinc Oxide Nanorods

    Directory of Open Access Journals (Sweden)

    Nguyen Tam Nguyen Truong

    2017-01-01

    Full Text Available ZnO nanorods (Nrods with ~20–50 nm lengths were synthesized using an aqueous solution of zinc acetate and glacial acetic acid. Bulk heterojunction solar cells were fabricated with the structure of indium tin oxide (ITO/polyethylenedioxythiophene doped with polystyrene-sulfonic acid (PEDOT:PSS/ZnO-Nrods + polymer/electron transport layer (ETL/Al. Current density-voltage characterization of the resulting cells showed that, by adding an ETL and using polymers with a low band gap energy, the photoactive layer surface morphology and the device performance can be dramatically improved.

  14. Encapsulating Quantum Dots into ZnO Nanorods for Advanced photonics and Laser Applications

    Science.gov (United States)

    2016-10-12

    axis of a hexagonal ZnO NMR is confined by total- internal reflections according to previous theoretical and experimental studies20,21. The use of QDs...monolayer of PMMA microspheres self-assembled on the GaN substrate, (b) Microporous TiO2 ring template obtained after removing PMMA microspheres. (c...TEM allows us to qualitatively probe the internal structure of the ZnO NMRs and composite QDs and to determine QDs distribution in ZnO NMRs surface

  15. Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fazhe; Zhao, Zengdian [Analysis and Testing Center, Shandong University of Technology, Zibo 255100 (China); Qiao, Xueliang, E-mail: xuelqiao@163.com [State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Tan, Fatang; Wang, Wei [State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China)

    2016-02-15

    Highlights: • We synthesized linked ZnO nanorods by a facile microwave method. • The effect of reaction parameters on ZnO was investigated. • ZnO bipods with different aspect ratios were prepared. • The photocatalytic performance of ZnO bipods was evaluated. - Abstract: Linked ZnO nanorods have been successfully prepared via a facile microwave method without any post-synthesis treatment. The X-ray diffraction (XRD) patterns indicated the precursor had completely transformed into the pure ZnO crystal. The images of field emitting scanning electron microscope (FESEM) and transmission electron microscope (TEM) showed that linked ZnO nanorods consisted predominantly of ZnO bipods. The formation process of the ZnO bipods was clearly discussed. ZnO bipods with different aspect ratios have been obtained by tuning the concentrations of reagents and microwave power. Moreover, the photocatalytic performance of ZnO bipods with different aspect ratios for degradation of methylene blue was systematically evaluated. The results of photocatalytic experiments showed that the photocatalytic activity increased with the aspect ratios of ZnO bipods increased. The reason is that ZnO bipods with larger aspect ratio have higher surface area, which can absorb more MB molecules to react with ·OH radicals.

  16. Sodium titanate nanorods: Preparation, microstructure characterization and photocatalytic activity

    Czech Academy of Sciences Publication Activity Database

    Štengl, Václav; Bakardjieva, Snejana; Šubrt, Jan; Večerníková, Eva; Szatmáry, Lórant; Klementová, Mariana; Balek, Vladimír

    2006-01-01

    Roč. 63, 1-2 (2006), s. 20-30 ISSN 0926-3373 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40320502 Keywords : sodium titanate * nanorods * ethylene glycol Subject RIV: CA - Inorganic Chemistry Impact factor: 3.942, year: 2006

  17. Time of Growth Dependent of ZnO-Nanorods by Self-Assembly Methods and its Structural Properties

    Science.gov (United States)

    Aprilia, A.; Bahtiar, A.; Safriani, L.; Ayunita, C. C.; Afifah, N.; Syakir, N.; Risdiana; Saragi, T.; Hidayat, S.; Fitrilawati; Siregar, R. E.

    2017-05-01

    ZnO-nanorods (ZnO-Nrs) have been successfully prepared on glass substrate using self-assembly method by varying deposition time. Zn acetate dehydrate and 2-methoxyethanol was used as raw material and solvent respectively (for ZnO seed layer preparation), meanwhile Zn nitrate hexahydrate and hexametylenetetramine (HMTA) dissolved in deionized water used as solution growth of ZnO-Nanorods (ZnO-Nrs). In this work, deposition times of ZnO-Nrs were varied by 120 min, 150 min, 180 min and 210 minutes at 100°C of annealing temperature. In order to investigate the physical properties of resulting ZnO, several measurements such as x-ray diffraction (XRD), ultra-violet visible spectroscopy and scanning electron microscopy (SEM) were carried out. Based on ZnO nanorods SEM image with varying time depositions, seems that increasing deposition time the nanorod size decrease but when the time reach 210 min, the average size of nanorods turned back increase. From XRD measurement, the average grain size and lattice constant (c) which is assemble the nanorod structure and lattice constant (c) was determined by Debye-Scherrer formula and Bragg law’s respectively. The growth process of ZnO nanorod by 180 min time deposition was known as an appropriate time to produce ZnO nanorods with high crystal quality due to sharp peak intensity of XRD spectrum.

  18. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jeng

    2013-01-01

    Full Text Available The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films prepared by TiO2 nanorods exhibited larger surface roughness than those prepared by the commercial TiO2 particles. It was found that a pure anatase phase of TiO2 nanorods can be obtained from the hydrothermal method. The dye-sensitized solar cells fabricated with TiO2 nanorods exhibited a higher solar efficiency than those fabricated with commercial TiO2 nanoparticles directly. Further, triple-layer structures of TiO2 thin films with different particle sizes were investigated to improve the solar efficiency.

  19. In-Doped ZnO Hexagonal Stepped Nanorods and Nanodisks as Potential Scaffold for Highly-Sensitive Phenyl Hydrazine Chemical Sensors.

    Science.gov (United States)

    Umar, Ahmad; Kim, Sang Hoon; Kumar, Rajesh; Al-Assiri, Mohammad S; Al-Salami, A E; Ibrahim, Ahmed A; Baskoutas, Sotirios

    2017-11-21

    Herein, we report the growth of In-doped ZnO (IZO) nanomaterials, i.e., stepped hexagonal nanorods and nanodisks by the thermal evaporation process using metallic zinc and indium powders in the presence of oxygen. The as-grown IZO nanomaterials were investigated by several techniques in order to examine their morphological, structural, compositional and optical properties. The detailed investigations confirmed that the grown nanomaterials, i.e., nanorods and nanodisks possess well-crystallinity with wurtzite hexagonal phase and grown in high density. The room-temperature PL spectra exhibited a suppressed UV emissions with strong green emissions for both In-doped ZnO nanomaterials, i.e., nanorods and nanodisks. From an application point of view, the grown IZO nanomaterials were used as a potential scaffold to fabricate sensitive phenyl hydrazine chemical sensors based on the I-V technique. The observed sensitivities of the fabricated sensors based on IZO nanorods and nanodisks were 70.43 μA·mM -1 cm -2 and 130.18 μA·mM -1 cm -2 , respectively. For both the fabricated sensors, the experimental detection limit was 0.5 μM, while the linear range was 0.5 μM-5.0 mM. The observed results revealed that the simply grown IZO nanomaterials could efficiently be used to fabricate highly sensitive chemical sensors.

  20. Active Layer Spin Coating Speed Dependence of Inverted Organic Solar Cell Based on Eosin-Y-Coated ZnO Nanorod Arrays

    Science.gov (United States)

    Ginting, R. T.; Yap, C. C.; Yahaya, M.; Fauzia, V.; Salleh, M. M.

    2013-04-01

    The active layer spin coating speed dependence of the performance of inverted organic solar cells (OSCs) based on Eosin-Y-coated ZnOnanorods has been investigated. An active layer consisted of poly(2-methoxy-5-(2'-ethyl)-hexyloxy-p-phenylenevinylene) (MEH-PPV) as donor and phenyl-c61-butyric acid methyl ester (PCBM) as acceptor was employed, whereas ZnO nanorods were utilized as electron transporting layer. The active layer was deposited on top of Eosin-Y-coated ZnO nanorods with various spin coating speeds (1000-4000 rpm). Inverted OSCs with a structure of FTO/Eosin-Y-coated ZnO nanorods/MEH-PPV:PCBM /Ag were characterized through the current density-voltage (J-V) measurement under illumination intensity of 100 mW/cm2. Based on the investigation, the short circuit current density (Jsc) and the power conversion efficiency (PCE) enhanced significantly, where as fill factor slightly increased with spin coating speed. The two-diode equivalent model was found to fit the experimental J-V curves very well. The optimum PCE of 1.18 ± 0.07% was achieved at the highest spin coating speed of 4000 rpm, as a result of the decrement of diffusion current density (Jdiff), recombination current density (Jrec), and ideality factor, thus further confirms the strong built-in electric field in thinner photoactive layer.

  1. ZnO nanorods/ZnS·(1,6-hexanediamine)(0.5) hybrid nanoplates hierarchical heteroarchitecture with improved electrochemical catalytic properties for hydrazine.

    Science.gov (United States)

    Wu, Zhengcui; Wu, Yaqin; Pei, Tonghui; Wang, Huan; Geng, Baoyou

    2014-03-07

    Novel hierarchical heteronanostructures of ZnO nanorods/ZnS·(HDA)0.5 (HDA = 1,6-hexanediamine) hybrid nanoplates on a zinc substrate are successfully synthesized on a large scale by combining hydrothermal growth (for ZnO nanorods) and liquid chemical conversion (for ZnS·(HDA)0.5 nanoplates) techniques. The formation of ZnS·(HDA)0.5 hybrid nanoplates branches takes advantage of the preferential binding of 1,6-hexanediamine on specific facets of ZnS, which makes the thickening rate much lower than the lateral growth rate. The ZnS·(HDA)0.5 hybrid nanoplates have a layered structure with 1,6-hexanediamine inserted into interlayers of wurtzite ZnS through the bonding of nitrogen. The number density and thickness of the secondary ZnS·(HDA)0.5 nanoplates can be conveniently engineered by variation of the sulfur source and straightforward adjustment of reactant concentrations such as 1,6-hexanediamine and the sulfur source. The fabricated ZnO/ZnS·(HDA)0.5 heteronanostructures show improved electrochemical catalytic properties for hydrazine compared with the primary ZnO nanorods. Due to its simplicity and efficiency, this approach could be similarly used to fabricate varieties of hybrid heterostructures made of materials with an intrinsic large lattice mismatch.

  2. Full coverage of perovskite layer onto ZnO nanorods via a modified sequential two-step deposition method for efficiency enhancement in perovskite solar cells

    Science.gov (United States)

    Ruankham, Pipat; Wongratanaphisan, Duangmanee; Gardchareon, Atcharawon; Phadungdhitidhada, Surachet; Choopun, Supab; Sagawa, Takashi

    2017-07-01

    Full coverage of perovskite layer onto ZnO nanorod substrates with less pinholes is crucial for achieving high-efficiency perovskite solar cells. In this work, a two-step sequential deposition method is modified to achieve an appropriate property of perovskite (MAPbI3) film. Surface treatment of perovskite layer and its precursor have been systematically performed and their morphologies have been investigated. By pre-wetting of lead iodide (PbI2) and letting it dry before reacting with methylammonium iodide (MAI) provide better coverage of perovskite film onto ZnO nanorod substrate than one without any treatment. An additional MAI deposition followed with toluene drop-casting technique on the perovskite film is also found to increase the coverage and enhance the transformation of PbI2 to MAPbI3. These lead to longer charge carrier lifetime, resulting in an enhanced power conversion efficiency (PCE) from 1.21% to 3.05%. The modified method could been applied to a complex ZnO nanorods/TiO2 nanoparticles substrate. The enhancement in PCE to 3.41% is observed. These imply that our introduced method provides a simple way to obtain the full coverage and better transformation to MAPbI3 phase for enhancement in performances of perovskite solar cells.

  3. Enhancement of UV photodetector properties of ZnO nanorods/PEDOT:PSS Schottky junction by NGQD sensitization along with conductivity improvement of PEDOT:PSS by DMSO additive

    Science.gov (United States)

    Dhar, Saurab; Majumder, Tanmoy; Chakraborty, Pinak; Mondal, Suvra Prakash

    2018-04-01

    Schottky junction ultraviolet (UV) photodetector was fabricated by spin coating a hole conducting polymer, poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS) on hydrothermally grown zinc oxide (ZnO) nanorod arrays. The UV detector performance was significantly improved two step process. Firstly, ZnO nanorods were modified by sensitizing N doped grapheme quantum dots (NGQDs) for better photoresponce behavior. Afterwards, the junction properties as well as photoresponse was enhanced by modifying electrical conductivity of PEDOT:PSS layer with organic solvent (DMSO). Our NGQD decorated ZnO NRs/DMSO-PEDOT:PSS Schottky junction device demonstrated superior external quantum efficiency (EQE ˜ 90063 %) and responsivity (Rλ˜247 A/W) at 340 nm wavelength and -1V external bias. The response and recovery times of the final photodetector device was very fast compared to GQD as well as NGQD modified and pristine ZnO nanorod based detectors.

  4. A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A

    International Nuclear Information System (INIS)

    Liu, Anran; Yin, Kaifei; Mi, Li; Ma, Mengyao; Liu, Yuanjian; Li, Ying; Wei, Wei; Zhang, Yuanjian; Liu, Songqin

    2017-01-01

    Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn 2+ displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL −1 and a wide linear range from 0.5 pg mL −1 to 10 μg mL −1 . The R 2 of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A. - Highlights: • A photoelectrochemical immunosensor based on ZnO NAs and NBs was fabricated. • Cosensitized structure of ZnO NAs, CdS and Mn improved the photocurrent response. • An excellent sensitivity and selectivity of NDPK-A detection was obtained.

  5. A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Anran, E-mail: liuar@seu.edu.cn; Yin, Kaifei; Mi, Li; Ma, Mengyao; Liu, Yuanjian; Li, Ying; Wei, Wei; Zhang, Yuanjian; Liu, Songqin

    2017-06-22

    Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn{sup 2+} displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL{sup −1} and a wide linear range from 0.5 pg mL{sup −1} to 10 μg mL{sup −1}. The R{sup 2} of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A. - Highlights: • A photoelectrochemical immunosensor based on ZnO NAs and NBs was fabricated. • Cosensitized structure of ZnO NAs, CdS and Mn improved the photocurrent response. • An excellent sensitivity and selectivity of NDPK-A detection was obtained.

  6. ZnO layers prepared by spray pyrolysis

    Science.gov (United States)

    Messaoudi, C.; Abd-Lefdil, S.; Sayah, D.; Cadene, M.

    1998-02-01

    Highly transparent undoped and indium doped ZnO thin films have been grown on glass substrates by using the spray pyrolysis process. Conditions of preparation have been optimized to get good quality and reproducible films with required properties. Polycrystalline films with an hexagonal Wurtzite-type structure were easily obtained under the optimum spraying conditions. Both of samples have shown high transmission coefficient in the visible and infrared wavelength range with sharp absorption edge around 380 nm which closely corresponds to the intrinsic band-gap of ZnO (3.2 eV). Orientation and crystallites size were remarkably modified by deposition temperature and indium doping. Des couches minces de ZnO, hautement transparentes, non dopées et dopées à l'indium ont été élaborées sur un substrat en verre par le procédé de pulvérisation chimique réactive spray. Les conditions de préparation ont été optimisées pour l'obtention de couches reproductibles, de bonne qualité et ayant les propriétés requises. Des films polycristallins, présentant une structure hexagonale de type Wurtzite, ont été aisément obtenus dans les conditions optimales de pulvérisation. Tous les échantillons ont présenté un coefficient de transmission élevé dans le domaine du visible et du proche infrarouge, avec une absorption brutale au voisinage de 380 nm, correspondant au gap optique du ZnO (3,2 eV). L'orientation et la taille des cristallites ont été remarquablement modifiées par la température du dépôt et par le dopage à l'indium.

  7. Oriented ZnO nanostructures and their application in photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Man, Minh Tan [Department of Physics, Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 54896 (Korea, Republic of); Kim, Ji-Hee [Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419 (Korea, Republic of); Sungkyunkwan University (SKKU), Suwon, 16419 (Korea, Republic of); Jeong, Mun Seok [Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon, 16419 (Korea, Republic of); Do, Anh-Thu Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Caugiay, Hanoi (Viet Nam); Lee, Hong Seok, E-mail: hslee1@jbnu.ac.kr [Department of Physics, Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 54896 (Korea, Republic of)

    2017-05-15

    We report a chemical bath deposition approach for the preparation of large arrays of oriented ZnO nanostructures by activated substrate processes, and precipitated ZnO nanorods by passive occupation of the crystal surface. Photoluminescence dynamics showed that various visible emission characteristics associated with defects such as oxygen vacancy, zinc interstitial or their complexes. In addition, the precipitated ZnO nanorods exhibited excellent performance in the adsorption and photocatalytic decomposition of organic dyes, achieving 95% photodegradation of Rhodamine 6B. Moreover, oxygen defects function as trap sites with strong adsorption abilities towards organic dyes and showed high performance in the photocatalytic degradation of the dye molecules.

  8. Photoelectrochemical water splitting under visible light over anti-photocorrosive In2O3-coupling ZnO nanorod arrays photoanode

    International Nuclear Information System (INIS)

    Zhang, Yan; Zhang, Jinqiu; Nie, Mengyan; Sun, Kai; Li, Chunhu; Yu, Jianqiang

    2015-01-01

    In 2 O 3 quantum dots with a high crystallinity were deposited on the surface of ZnO nanorods through a chemistry bath method. The resulting In 2 O 3 -sensitizing ZnO nanorod arrays not only exhibited enhanced photoelectrochemical activity for water splitting under visible-light irradiation, but also possessed anti-photocorrosion property. The photo-induced charge-transfer property of In 2 O 3 could be improved greatly by coupling with ZnO. This observation demonstrated that the heterojunction at the interface between In 2 O 3 and ZnO could efficiently reduce the recombination of photo-induced electron–hole pairs and increase the lifetime of charge carriers and therefore enhance the photo-to-current efficiency of the In 2 O 3 –ZnO nanocrystalline arrays. It reveals that the heterojunction construction between two different semiconductors plays a very important role in determining the dynamic properties of their photogenerated charge carriers and their photo-to-current conversion efficiency

  9. Photoelectrochemical water splitting under visible light over anti-photocorrosive In{sub 2}O{sub 3}-coupling ZnO nanorod arrays photoanode

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan, E-mail: zhangyanchem@qdu.edu.cn [Oceanology University of China, College of Chemistry and Chemical Engineering (China); Zhang, Jinqiu [Qingdao University, Faculty of Chemical Science and Engineering (China); Nie, Mengyan [University of Southampton, National Centre for Advanced Tribology at Southampton, School of Engineering Sciences (United Kingdom); Sun, Kai [Qingdao University, Faculty of Chemical Science and Engineering (China); Li, Chunhu [Oceanology University of China, College of Chemistry and Chemical Engineering (China); Yu, Jianqiang [Qingdao University, Faculty of Chemical Science and Engineering (China)

    2015-07-15

    In{sub 2}O{sub 3} quantum dots with a high crystallinity were deposited on the surface of ZnO nanorods through a chemistry bath method. The resulting In{sub 2}O{sub 3}-sensitizing ZnO nanorod arrays not only exhibited enhanced photoelectrochemical activity for water splitting under visible-light irradiation, but also possessed anti-photocorrosion property. The photo-induced charge-transfer property of In{sub 2}O{sub 3} could be improved greatly by coupling with ZnO. This observation demonstrated that the heterojunction at the interface between In{sub 2}O{sub 3} and ZnO could efficiently reduce the recombination of photo-induced electron–hole pairs and increase the lifetime of charge carriers and therefore enhance the photo-to-current efficiency of the In{sub 2}O{sub 3}–ZnO nanocrystalline arrays. It reveals that the heterojunction construction between two different semiconductors plays a very important role in determining the dynamic properties of their photogenerated charge carriers and their photo-to-current conversion efficiency.

  10. Spatially Correlated, Single Nanomaterial-Level Structural and Optical Profiling of Cu-Doped ZnO Nanorods Synthesized via Multifunctional Silicides

    Directory of Open Access Journals (Sweden)

    Johnson Truong

    2018-04-01

    Full Text Available We demonstrate a straightforward and effective method to synthesize vertically oriented, Cu-doped ZnO nanorods (NRs using a novel multipurpose platform of copper silicide nanoblocks (Cu3Si NBs preformed laterally in well-defined directions on Si. The use of the surface-organized Cu3Si NBs for ZnO NR growth successfully results in densely assembled Cu-doped ZnO NRs on each NB platform, whose overall structures resemble thick bristles on a brush head. We show that Cu3Si NBs can uniquely serve as a catalyst for ZnO NRs, a local dopant source of Cu, and a prepatterned guide to aid the local assembly of the NRs on the growth substrate. We also ascertain the crystalline structures, optical properties, and spectroscopic signatures of the Cu-doped ZnO NRs produced on the NBs, both at each module of NRs/NB and at their ensemble level. Subsequently, we determine their augmented properties relative to the pristine form of undoped ZnO NRs and the source material of Cu3Si NBs. We provide spatially correlated structural and optical data for individual modules of Cu-doped ZnO NRs assembled on a Cu3Si NB by resolving them along the different positions on the NB. Ensemble-averaged versus individual behaviors of Cu-doped ZnO NRs on Cu3Si NBs are then compared. We further discuss the potential impact of such ZnO-derived NRs on their relatively unexplored biological and biomedical applications. Our efforts will be particularly useful when exploiting each integrated module of self-aligned, Cu-doped ZnO NRs on a NB as a discretely addressable, active element in solid-state sensors and miniaturized luminescent bioprobes.

  11. Decoration of ZnO Nanorods with Coral Reefs like NiO Nanostructures by the Hydrothermal Growth Method and Their Luminescence Study

    Directory of Open Access Journals (Sweden)

    Mazhar Ali Abbasi

    2014-01-01

    Full Text Available Composite nanostructures of coral reefs like p-type NiO/n-type ZnO were synthesized on fluorine-doped tin oxide glass substrates by hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction techniques. This investigation shows that the adopted synthesis leads to high crystalline quality nanostructures. The morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL spectra for the synthesized composite nanostructures are dominated mainly by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence of the decorated ZnO nanostructures is enhanced by the presence of the NiO.

  12. MOF-5 decorated hierarchical ZnO nanorod arrays and its photoluminescence

    Science.gov (United States)

    Zhang, Yinmin; Lan, Ding; Wang, Yuren; Cao, He; Jiang, Heng

    2011-04-01

    The strategy to manipulate nanoscale materials into well-organized hierarchical architectures is very important to both material synthesis and nanodevice applications. Here, nanoscale MOF-5 crystallites were successfully fabricated onto ordered hierarchical ZnO arrays based on aqueous chemical synthesis and molecule self-assembly technology guided room temperature diffusion method, which has the advantages of energy saving and simple operation. The structures and morphologies of the samples were performed by X-ray powder diffraction and field emission scanning electronic microscopy. The MOF-5 crystallites have good quality and bind well to the hexagonal-patterned ZnO arrays. The photoluminescence spectrum shows that the emission of hybrid MOF-5-ZnO films displays a blue shift in green emission and intensity reduction in UV emission. This ordered hybrid semiconductor material is expected to exploit the great potentiality in sensors, micro/nanodevices, and screen displays.

  13. Growth of ZnS-coated ZnO nanorod arrays on (1 0 0) silicon substrate by two-step chemical synthesis

    International Nuclear Information System (INIS)

    Kumarakuru, Haridas; Urgessa, Zelalem N.; Olivier, Ezra J.; Botha, Johannes R.; Venter, Andre; Neethling, Johannes H.

    2014-01-01

    Highlights: • ZnS coated ZnO nanorods were synthesized using a simple two-step chemical method. • The uniform ZnS coating exhibits a polycrystalline face centered cubic structure. • Initial ZnS deposit exhibits a partial epitaxial relationship with ZnO. • An ion-exchange reaction was deduced for this sulphidation process. • Detailed microscopy results are complemented by room temperature photoluminescence. - Abstract: In this study, ZnS coated ZnO nanorods were synthesized using a simple, cost effective two-step chemical method. A continuous coating of ZnS on a ZnO nanorod, having a uniform thickness, is demonstrated using high resolution transmission electron microscopy, electron energy loss spectroscopy and selected area diffraction (SAD). These core–shell structures can be produced at relatively low temperatures (75 °C) and within relatively short times (3 h). The ZnS coating exhibits a polycrystalline structure with a lattice parameter of 5.35 Å, which is 1.1% smaller than the unstrained cubic zinc-blende structure. The SAD pattern taken at the ZnO–ZnS interface exhibits a partial epitaxial relationship, where (1 0 –1 0) ZnO//(1 1 1) ZnS. Our detailed analysis shows that the ZnS shell comprises two different regions: a ZnS rich inner shell region is produced via the first sulphidation process, followed by a mixture of ZnO and ZnS in the outer shell region during the second treatment. From the detailed microscopy results a growth mechanism is proposed for each step of the sulphidation process. The results are complemented by room temperature photoluminescence spectroscopy. Strong emission from free excitons in ZnO is observed at 3.27 eV before ZnS coating, while a composite band peaking at 2.9 eV is measured after sulphidation. The origin of the latter will be discussed

  14. Growth of ZnS-coated ZnO nanorod arrays on (1 0 0) silicon substrate by two-step chemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kumarakuru, Haridas, E-mail: haridas.kumarakuru@nmmu.ac.za [Centre for High Resolution Transmission Electron Microscopy (CHRTEM), Department of Physics, P.O.Box 77000, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth 6031 (South Africa); Urgessa, Zelalem N. [Department of Physics, Nelson Mandela Metropolitan University (NMMU), P.O. Box 77000, Port Elizabeth 6031 (South Africa); Olivier, Ezra J. [Centre for High Resolution Transmission Electron Microscopy (CHRTEM), Department of Physics, P.O.Box 77000, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth 6031 (South Africa); Botha, Johannes R.; Venter, Andre [Department of Physics, Nelson Mandela Metropolitan University (NMMU), P.O. Box 77000, Port Elizabeth 6031 (South Africa); Neethling, Johannes H. [Centre for High Resolution Transmission Electron Microscopy (CHRTEM), Department of Physics, P.O.Box 77000, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth 6031 (South Africa); Department of Physics, Nelson Mandela Metropolitan University (NMMU), P.O. Box 77000, Port Elizabeth 6031 (South Africa)

    2014-11-05

    Highlights: • ZnS coated ZnO nanorods were synthesized using a simple two-step chemical method. • The uniform ZnS coating exhibits a polycrystalline face centered cubic structure. • Initial ZnS deposit exhibits a partial epitaxial relationship with ZnO. • An ion-exchange reaction was deduced for this sulphidation process. • Detailed microscopy results are complemented by room temperature photoluminescence. - Abstract: In this study, ZnS coated ZnO nanorods were synthesized using a simple, cost effective two-step chemical method. A continuous coating of ZnS on a ZnO nanorod, having a uniform thickness, is demonstrated using high resolution transmission electron microscopy, electron energy loss spectroscopy and selected area diffraction (SAD). These core–shell structures can be produced at relatively low temperatures (75 °C) and within relatively short times (3 h). The ZnS coating exhibits a polycrystalline structure with a lattice parameter of 5.35 Å, which is 1.1% smaller than the unstrained cubic zinc-blende structure. The SAD pattern taken at the ZnO–ZnS interface exhibits a partial epitaxial relationship, where (1 0 –1 0) ZnO//(1 1 1) ZnS. Our detailed analysis shows that the ZnS shell comprises two different regions: a ZnS rich inner shell region is produced via the first sulphidation process, followed by a mixture of ZnO and ZnS in the outer shell region during the second treatment. From the detailed microscopy results a growth mechanism is proposed for each step of the sulphidation process. The results are complemented by room temperature photoluminescence spectroscopy. Strong emission from free excitons in ZnO is observed at 3.27 eV before ZnS coating, while a composite band peaking at 2.9 eV is measured after sulphidation. The origin of the latter will be discussed.

  15. Low-temperature growth of well-aligned zinc oxide nanorod arrays on silicon substrate and their photocatalytic application

    Directory of Open Access Journals (Sweden)

    Azam A

    2014-04-01

    Full Text Available Ameer Azam,1 Saeed Salem Babkair21Center of Nanotechnology, King Abdulaziz University, Jeddah, Saudi Arabia; 2Center of Nanotechnology, Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi ArabiaAbstract: Well-aligned and single-crystalline zinc oxide (ZnO nanorod arrays were grown on silicon (Si substrate using a wet chemical route for the photodegradation of organic dyes. Structural analysis using X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction confirmed the formation of ZnO nanorods grown preferentially oriented in the (001 direction and with a single phase nature with a wurtzite structure. Field emission scanning electron microscopy and transmission electron microscopy micrographs showed that the length and diameter of the well-aligned rods were about ~350–400 nm and ~80–90 nm, respectively. Raman scattering spectra of ZnO nanorod arrays revealed the characteristic E2 (high mode that is related to the vibration of oxygen atoms in the wurtzite ZnO. The photodegradation of methylene blue (MB using ZnO nanorod arrays was performed under ultraviolet light irradiation. The results of photodegradation showed that ZnO nanorod arrays were capable of degrading ~80% of MB within 60 minutes of irradiation, whereas ~92% of degradation was achieved in 120 minutes. Complete degradation of MB was observed after 270 minutes of irradiation time. Owing to enhanced photocatalytic degradation efficiency and low-temperature growth method, prepared ZnO nanorod arrays may open up the possibility for the successful utilization of ZnO nanorod arrays as a future photocatalyst for environmental remediation.Keywords: ZnO, nanorods, XRD, photodegradation

  16. Evolution of Structural and Optical Properties of ZnO Nanorods Grown on Vacuum Annealed Seed Crystallites

    Directory of Open Access Journals (Sweden)

    Waqar Khan

    2018-01-01

    Full Text Available In this study, the ambient condition for the as-coated seed layer (SL annealing at 350 °C is varied from air or nitrogen to vacuum to examine the evolution of structural and optical properties of ZnO nanorods (NRs. The NR crystals of high surface density (~240 rods/μm2 and aspect ratio (~20.3 show greatly enhanced (002 degree of orientation and crystalline quality, when grown on the SLs annealed in vacuum, compared to those annealed in air or nitrogen ambient. This is due to the vacuum-annealed SL crystals of a highly preferred orientation toward (002 and large grain sizes. X-ray photoelectron spectroscopy also reveals that the highest O/Zn atomic ratio of 0.89 is obtained in the case of vacuum-annealed SL crystals, which is due to the effective desorption of hydroxyl groups and other contaminants adsorbed on the surface formed during aqueous solution-based growth process. Near band edge emission (ultra violet range of 360–400 nm of the vacuum-annealed SLs is also enhanced by 44% and 33% as compared to those annealed in air and nitrogen ambient, respectively, in photoluminescence with significant suppression of visible light emission associated with deep level transition. Due to this improvement of SL optical crystalline quality, the NR crystals grown on the vacuum-annealed SLs produce ~3 times higher ultra violet emission intensity than the other samples. In summary, it is shown that the ZnO NRs preferentially grow along the wurtzite c-axis direction, thereby producing the high crystalline quality of nanostructures when they grow on the vacuum-annealed SLs of high crystalline quality with minimized impurities and excellent preferred orientation. The ZnO nanostructures of high crystalline quality achieved in this study can be utilized for a wide range of potential device applications such as laser diodes, light-emitting diodes, piezoelectric transducers and generators, gas sensors, and ultraviolet detectors.

  17. Synthesis of Highly Concentrated ZnO Nanorod Sol by Sol-gel Method and their Applications for Inverted Organic Solar Cells

    International Nuclear Information System (INIS)

    Kim, Solee; Kim, Young Chai; Oh, Seong-Geun

    2015-01-01

    The effects of the zinc oxide (ZnO) preparing process on the performance of inverted organic photovoltaic cells (OPVs) were explored. The morphology and size of ZnO nanoparticles were controlled, leading to more efficient charge collection from device and higher electron mobility compared with nanospheres. Nanosized ZnO particles were synthesized by using zinc acetate dihydrate and potassium hydroxide in methanol. Also, water was added into the reaction medium to control the morphology of ZnO nanocrystals from spherical particles to rods, and NH 4 OH was used to prevent the gelation of dispersion. Solution-processed ZnO thin films were deposited onto the ITO/glass substrate by using spin coating process and then ZnO films were used as an electron transport layer in inverted organic photovoltaic cells. The analyses were carried out by using TEM, FE-SEM, AFM, DLS, UV-Vis spectroscopy, current density-voltage characteristics and solar simulator

  18. Photoelectrochemical properties of hierarchical ZnO micro-nanostructure sensitized with Sb2S3 nanoparticles

    Directory of Open Access Journals (Sweden)

    Zhimin GUO

    2016-02-01

    Full Text Available By using electrochemical deposition method, and assisted with additions of PEG-400 and EDA, well-aligned ZnO nanorods and hierarchical ZnO micro-nanostructure are fabricated directly on indium doped tin oxide coated conducting glass (ITO substrate. The shell-core Sb2S3/ZnO nanorod structure and the shell-core hierarchical Sb2S3/ZnO micro-nanostructure are prepared by chemical bath deposition method. SEM, XRD, UV-Vis and photocurrent test are used to characterize the morphology, nanostructures and their photoelectrochemical properties. The studies show that the photocurrent on the array membranes with shell-core hierarchical Sb2S3/ZnO micro-nanostructure is apparently higher than that with shell-core Sb2S3/ZnO nanorods array.

  19. Preparation and characterization of Ce-doped ZnO nanofibers by an electrospinning method

    Directory of Open Access Journals (Sweden)

    Jong-Pil Kim

    2011-02-01

    Full Text Available ZnO and Ce-doped ZnO Nanofibers on (111 Pt/SiO2/Si substrates were produced using an electrospinning technique. The as-prepared composite fibres were subjected to high-temperature calcination to produce inorganic fibers. After calcining at a temperature of 500 °C, the average diameter of the ZnO and Ce-doped ZnO nanofibers were determined to be 170 nm and 225 nm, respectively. The average grain size of the ZnO and Ce-doped ZnO nanofibers were about 50 nm and 57 nm, respectively. The microstructure, chemical bonding state and photoluminescence of the produced ZnO and Ce-doped ZnO nanofibers were investigated. The Ce-doped ZnO nanofiber can be assigned to the presence of Ce ions on substitutional sites of Zn ions and the Ce3+ state from X-ray photoelectron spectra. Compared with PL spectra of ZnO nanofibers, the peak position of the UV emission of the Ce-doped ZnO nanofibers is sharply suppressed while the green emission band is highly enhanced.

  20. ZnO nanorods/ZnS.(1,6-hexanediamine)0.5 hybrid nanoplates hierarchical heteroarchitecture with improved electrochemical catalytic properties for hydrazine

    Science.gov (United States)

    Wu, Zhengcui; Wu, Yaqin; Pei, Tonghui; Wang, Huan; Geng, Baoyou

    2014-02-01

    Novel hierarchical heteronanostructures of ZnO nanorods/ZnS.(HDA)0.5 (HDA = 1,6-hexanediamine) hybrid nanoplates on a zinc substrate are successfully synthesized on a large scale by combining hydrothermal growth (for ZnO nanorods) and liquid chemical conversion (for ZnS.(HDA)0.5 nanoplates) techniques. The formation of ZnS.(HDA)0.5 hybrid nanoplates branches takes advantage of the preferential binding of 1,6-hexanediamine on specific facets of ZnS, which makes the thickening rate much lower than the lateral growth rate. The ZnS.(HDA)0.5 hybrid nanoplates have a layered structure with 1,6-hexanediamine inserted into interlayers of wurtzite ZnS through the bonding of nitrogen. The number density and thickness of the secondary ZnS.(HDA)0.5 nanoplates can be conveniently engineered by variation of the sulfur source and straightforward adjustment of reactant concentrations such as 1,6-hexanediamine and the sulfur source. The fabricated ZnO/ZnS.(HDA)0.5 heteronanostructures show improved electrochemical catalytic properties for hydrazine compared with the primary ZnO nanorods. Due to its simplicity and efficiency, this approach could be similarly used to fabricate varieties of hybrid heterostructures made of materials with an intrinsic large lattice mismatch.Novel hierarchical heteronanostructures of ZnO nanorods/ZnS.(HDA)0.5 (HDA = 1,6-hexanediamine) hybrid nanoplates on a zinc substrate are successfully synthesized on a large scale by combining hydrothermal growth (for ZnO nanorods) and liquid chemical conversion (for ZnS.(HDA)0.5 nanoplates) techniques. The formation of ZnS.(HDA)0.5 hybrid nanoplates branches takes advantage of the preferential binding of 1,6-hexanediamine on specific facets of ZnS, which makes the thickening rate much lower than the lateral growth rate. The ZnS.(HDA)0.5 hybrid nanoplates have a layered structure with 1,6-hexanediamine inserted into interlayers of wurtzite ZnS through the bonding of nitrogen. The number density and thickness of the

  1. Influence of the spray pyrolysis seeding and growth parameters on the structure and optical properties of ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Juan, E-mail: jrodriguez@uni.edu.pe [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31 (Peru); Feuillet, Guy [CEA Grenoble/LETI, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Donatini, Fabrice [Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Onna, Diego [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Sanchez, Luis [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31 (Peru); Candal, Roberto [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); ECyT, 3iA, Universidad Nacional de San Martín, Martín de Irigoyen N° 3100 (1650), San Martín, Pcia de Buenos Aires (Argentina); Marchi, M. Claudia [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); CMA, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina); Bilmes, Sara A. [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Chandezon, Frédéric [University Grenoble Alpes, INAC-SPRAM, F-38000 Grenoble (France); CNRS, INAC-SPRAM, F-38000 Grenoble (France); CEA, INAC-SPRAM, F-38000 Grenoble (France)

    2015-02-01

    ZnO nanorods (NRs) were grown on fluorine doped tin oxide (FTO) substrates at low temperatures (90 °C) from Zn{sup 2+} precursors in alkaline media previously seeded with ZnO nanoparticles. These were deposited onto the FTO substrate heated at 350 °C by spray pyrolysis of a Zn acetate solution in a water ethanol mixture. The structure of seeds was tuned by the ethanol to water ratio, Γ, which controls the solvent evaporation rate of drops impinging the substrate. From a detailed characterization using a combination of scanning electron microscopy, X-ray diffraction, UV–visible absorption and cathodoluminescence spectroscopies, the dependence of the morphology and optical properties of the ZnO NRs on the seeding conditions was demonstrated. NRs grown on seeds deposited from solutions with Γ in the 0.03–0.06 range – i.e. when the surface excess of ethanol in the water–ethanol mixture has a maximum – show thinner average diameters and stacking faults due to the presence of zinc blende domains embedded into an overall wurtzite NR. They furthermore exhibit blue-shifted near band edge emission peak and a high deep level emission in cathodoluminescence. All these findings support the use of spray pyrolysis as a simple and reproducible way to control the seeds deposition, influencing the growth, the structure and the optical properties of the final ZnO NRs. - Highlights: • ZnO pyrolytic seeds tuned by the rate of solvent evaporation. • ZnO NRs grown from tuned pyrolytic seed's structure shows diameter dependence. • ZnO NRs show stacking faults due to the presence of zinc blende domains.

  2. Preparation and characterization of VOx nanorods using pulsed laser deposition technique

    International Nuclear Information System (INIS)

    Rama, N.; Senthil Kumar, E.; Ramachandra Rao, M.S.

    2009-01-01

    Full text: Vanadium oxide (VO x ) is one of the most functional oxides of the transition metal oxide family. This versatility comes because of the ability of Vanadium to exist as both monovalent and multivalent in these oxides. These oxides find potential usage in the field of thermochromism electrochromism catalysts, electrochemistry etc. especially in their nano-form because of their increased sensitivity to these applications. These nano-forms are usually prepared using conventional techniques such as solgel techniques, vapour phase transport, hydrothermal synthesis etc. In this work we have used pulsed laser deposition technique to fabricate vanadium oxide nanorods for the first time. The grown nanorods has a predominant VO 2 phase with a secondary phase of V 3 O 7 . The diameters of the rods were around 300 nm with Raman spectra showing all the group vibrations corresponding to VO x phase. The nanorods exhibited photoluminescence in the visible range due to the presence of oxygen defects. These results, including the mechanism of growth of these nanorods, will be discussed in detail. The existence of multivalence in these rods finds potential applications in electrochemistry while the visible photoluminescence in optical applications

  3. Void Structures in Regularly Patterned ZnO Nanorods Grown with the Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yu-Feng Yao

    2014-01-01

    Full Text Available The void structures and related optical properties after thermal annealing with ambient oxygen in regularly patterned ZnO nanrorod (NR arrays grown with the hydrothermal method are studied. In increasing the thermal annealing temperature, void distribution starts from the bottom and extends to the top of an NR in the vertical (c-axis growth region. When the annealing temperature is higher than 400°C, void distribution spreads into the lateral (m-axis growth region. Photoluminescence measurement shows that the ZnO band-edge emission, in contrast to defect emission in the yellow-red range, is the strongest under the n-ZnO NR process conditions of 0.003 M in Ga-doping concentration and 300°C in thermal annealing temperature with ambient oxygen. Energy dispersive X-ray spectroscopy data indicate that the concentration of hydroxyl groups in the vertical growth region is significantly higher than that in the lateral growth region. During thermal annealing, hydroxyl groups are desorbed from the NR leaving anion vacancies for reacting with cation vacancies to form voids.

  4. An efficient way to prepare silver nanorods in high concentration by polyol method without adding other metal or salt

    International Nuclear Information System (INIS)

    Chen Yong; Guan Jianguo; Xie Hongquan

    2012-01-01

    Using ethylene glycol as solvent and reductant, polyvinyl pyrrolidone(PVP) as capping agent under the action of appropriately preformed silver crystal seeds and controlled addition rates of silver nitrate and PVP solution, silver nanorods with length of 2–15 μm and diameter of 200–880 nm can be obtained in high concentration of AgNO 3 as 0.50 M. In the absence of the preformed seeds, nanorods cannot be obtained as the main product, if the AgNO 3 concentration is over 0.10 M. It is necessary to use the appropriately preformed silver crystal seeds for the high concentration preparation of silver nanorods. Transmission Electron Microscopy images showed that Ag seeds preformed at appropriate silver nitrate concentrations exhibited the multiply twinned particles of decahedral shape(MTPs), which formed Ag nanorods in the presence of PVP. Through study of the effects of various factors on the nanostructure of silver, the favorable conditions are: appropriately preformed seeds concentration at 6.54–9.81 mM, addition rate of AgNO 3 solution at 0.30–0.43 mL min −1 and molar ratio of PVP/AgNO 3 at 1.1–1.4, in order to control the crystal growth rate of silver matching the reduction rate of AgNO 3 by ethylene glycol. The nanorods obtained were characterized by Scanning Electron Microscopy, EDX, XRD, Raman spectrometry, Infrared Spectrophotometry and Ultraviolet Spectrophotometry. On the base of the above results, the mechanism of rates matching for obtaining silver nanorods was briefly discussed. This method is a simple, facile and economical method using high concentration with high yield without using other metal or salt to massively synthesize silver nanorods through adding preformed silver seeds to control the reduction rate of silver nitrate and the crystal growth rate of silver nanorods. As compared to the conventional polyol method using lower silver nitrate concentration, this method can save ethylene glycol used and time of operation and the as-prepared

  5. Synthesis of reduced graphene oxide/ZnO nanorods composites on graphene coated PET flexible substrates

    International Nuclear Information System (INIS)

    Huang, Lei; Guo, Guilue; Liu, Yang; Chang, Quanhong; Shi, Wangzhou

    2013-01-01

    Graphical abstract: - Highlights: • ZnO nanorods synthesized on CVD-graphene and rGO surfaces, respectively. • ZnO/CVD-graphene and ZnO/rGO form a distinctive porous 3D structure. • rGO/ZnO nanostructures possibility in energy storage devices. - Abstract: In this work, reduced graphene oxide (rGO)/ZnO nanorods composites were synthesized on graphene coated PET flexible substrates. Both chemical vapor deposition (CVD) graphene and reduced graphene oxide (rGO) films were prepared following by hydrothermal growth of vertical aligned ZnO nanorods. Reduced graphene sheets were then spun coated on the ZnO materials to form a three dimensional (3D) porous nanostructure. The morphologies of the ZnO/CVD graphene and ZnO/rGO were investigated by SEM, which shows that the ZnO nanorods grown on rGO are larger in diameters and have lower density compared with those grown on CVD graphene substrate. As a result of fact, the rough surface of nano-scale ZnO on rGO film allows rGO droplets to seep into the large voids of ZnO nanorods, then to form the rGO/ZnO hierarchical structure. By comparison of the different results, we conclude that rGO/ZnO 3D nanostructure is more desirable for the application of energy storage devices

  6. Decoration of PbS nanoparticles on Al-doped ZnO nanorod array thin film with hydrogen treatment as a photoelectrode for solar water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Chih-Hsiung; Chen, Chao-Hong [Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Chen, Dong-Hwang, E-mail: chendh@mail.ncku.edu.tw [Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

    2013-03-25

    Highlights: ► AZO nanorod array thin film is used as a photoanode for solar water splitting. ► Hydrogen treatment and sensitization by PbS nanoparticles enhance photocurrent. ► A novel ITO/FTO-free composite photoelectrode is developed. ► The pre-fabrication and use of an extra TCO thin film substrate is unnecessary. -- Abstract: Al-doped ZnO (AZO) nanorod arrays thin film with hydrogen treatment is directly used as a photoelectrode for solar water splitting without an extra transparent conducting oxide (TCO) thin film because it possesses the functions of TCO thin film and photoactive 1-dimensional nanostructured semiconductor simultaneously. To enhance the absorption in the visible region, PbS nanoparticles decorated the AZO nanorods via successive ionic layer adsorption and reaction route. The PbS nanoparticles have a face-centered cubic structure and their decoration does not destroy the 1-dimensional morphology of AZO nanorod arrays. With increasing the cycle number of PbS nanoparticles decoration, the grain size and loading of PbS nanoparticles become larger gradually which leads to lower energy bandgap and stronger absorption. A maximum photocurrent density of 1.65 mW cm{sup −2} is obtained when the cycle number is 20, which is much higher than those without PbS nanoparticles sensitization or hydrogen treatment. This demonstrates that the AZO nanorod array thin film with hydrogen treatment can be directly used as a photoelectrode without an extra TCO thin film. Because the use of expensive metals can be avoided and the pre-fabrication of TCO thin film substrate is necessary no more, the fabrication of such a composite photoelectrode becomes simple and low-cost. So, it has great potentials in solar water splitting after sensitization by quantum dots capable of visible light absorption.

  7. Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2012-11-01

    Full Text Available A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD on ZnO nanorods (ZnO-NRs has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS. The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 × 10−6 mM to 0.5 × 10−4 mM, and from 0.5 × 10−4 mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10−3 mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

  8. Indirect determination of mercury ion by inhibition of a glucose biosensor based on ZnO nanorods.

    Science.gov (United States)

    Chey, Chan Oeurn; Ibupoto, Zafar Hussain; Khun, Kimleang; Nur, Omer; Willander, Magnus

    2012-11-06

    A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 × 10(-6) mM to 0.5 × 10(-4) mM, and from 0.5 × 10(-4) mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10(-3) mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

  9. Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes

    Science.gov (United States)

    Zaman, Saima; Zainelabdin, Ahmed; Amin, Gul; Nur, Omer; Willander, Magnus

    2012-09-01

    The effects of the polymer concentration on the performance of hybrid light emitting diodes (LEDs) based on zinc oxide nanorods (ZnO NRs) and poly(9,9-dioctylfluorene) (PFO) were investigated. Various characterization techniques were applied to study the performance of the PFO/ZnO NR hybrid LEDs fabricated with various PFO concentrations. The fabricated hybrid LEDs demonstrated stable rectifying diode behavior, and it was observed that the turn-on voltage of the LEDs is concentration dependent. The measured room temperature electroluminescence (EL) showed that the PFO concentration plays a critical role in the emission spectra of the hybrid LEDs. At lower PFO concentrations of 2-6 mg/ml, the EL spectra are dominated by blue emission. However, by increasing the concentration to more than 8 mg/ml, the blue emission was completely suppressed while the green emission was dominant. This EL behavior was explained by a double trap system of excitons that were trapped in the β-phase and/or in the fluorenone defects in the PFO side. The effects of current injection on the hybrid LEDs and on the EL emission were also investigated. Under a high injection current, a new blue peak was observed in the EL spectrum, which was correlated to the creation of a new chemical species on the PFO chain. The green emission peak was also enhanced with increasing injection current because of the fluorenone defects. These results indicate that the emission spectra of the hybrid LEDs can be tuned by using different polymer concentrations and by varying the current injected into the device.

  10. Piezoelectric coupling in a field-effect transistor with a nanohybrid channel of ZnO nanorods grown vertically on graphene.

    Science.gov (United States)

    Quang Dang, Vinh; Kim, Do-Il; Thai Duy, Le; Kim, Bo-Yeong; Hwang, Byeong-Ung; Jang, Mi; Shin, Kyung-Sik; Kim, Sang-Woo; Lee, Nae-Eung

    2014-12-21

    Piezoelectric coupling phenomena in a graphene field-effect transistor (GFET) with a nano-hybrid channel of chemical-vapor-deposited Gr (CVD Gr) and vertically aligned ZnO nanorods (NRs) under mechanical pressurization were investigated. Transfer characteristics of the hybrid channel GFET clearly indicated that the piezoelectric effect of ZnO NRs under static or dynamic pressure modulated the channel conductivity (σ) and caused a positive shift of 0.25% per kPa in the Dirac point. However, the GFET without ZnO NRs showed no change in either σ or the Dirac point. Analysis of the Dirac point shifts indicated transfer of electrons from the CVD Gr to ZnO NRs due to modulation of their interfacial barrier height under pressure. High responsiveness of the hybrid channel device with fast response and recovery times was evident in the time-dependent behavior at a small gate bias. In addition, the hybrid channel FET could be gated by mechanical pressurization only. Therefore, a piezoelectric-coupled hybrid channel GFET can be used as a pressure-sensing device with low power consumption and a fast response time. Hybridization of piezoelectric 1D nanomaterials with a 2D semiconducting channel in FETs enables a new design for future nanodevices.

  11. Contact light-emitting diodes based on vertical ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Panin, G. N. [Dongguk University, Seoul (Korea, Republic of); Russian Academy of Sciences, Chernogolovka, Moscow district (Russian Federation); Cho, H. D.; Lee, S. W.; Kang, T. W. [Dongguk University, Seoul (Korea, Republic of)

    2014-05-15

    We report vertical contact light-emitting diodes (VCLEDs), that are based on heterojunctions formed by using the point contacts of n-ZnO nanorods (NRs) to the p-type semiconductor substrate and that are fabricated using a new approach to the formation of LEDs (Appl. Phys. Lett. 98, 093110 (2011)). A p-type GaN film grown on a sapphire substrate was used to form n-ZnO NRs/pGaN VCLEDs on a large area of about 4 cm{sup 2}. The VCLEDs emitted a pure blue electroluminescence with high efficiency. Electroluminescence at 470 nm, which is visible to the naked eye, started at small current of about 50 μA and is attributed to the good optical properties of the structurally perfect heterojunctions in the point contacts. The VCLED configuration allows the creation of ZnO/p-GaN nano-LEDs of high density and high-quality with a greatly reduced concentration of nonradiative defects in the active regions. The VCLEDs showed the high brightness of light required for active matrix displays and general solid-state lighting.

  12. Hierarchical core-shell structure of ZnO nanorod@NiO/MoO₂ composite nanosheet arrays for high-performance supercapacitors.

    Science.gov (United States)

    Hou, Sucheng; Zhang, Guanhua; Zeng, Wei; Zhu, Jian; Gong, Feilong; Li, Feng; Duan, Huigao

    2014-08-27

    A hierarchical core-shell structure of ZnO nanorod@NiO/MoO2 composite nanosheet arrays on nickel foam substrate for high-performance supercapacitors was constructed by a two-step solution-based method involving two hydrothermal processes followed by a calcination treatment. Compared to one composed of pure NiO/MoO2 composite nanosheets, the hierarchical core-shell structure electrode displays better pseudocapacitive behaviors in 2 M KOH, including high areal specific capacitance values of 1.18 F cm(-2) at 5 mA cm(-2) and 0.6 F cm(-2) at 30 mA cm(-2) as well as relatively good rate capability at high current densities. Furthermore, it also shows remarkable cycle stability, remaining at 91.7% of the initial value even after 4000 cycles at a current density of 10 mA cm(-2). The enhanced pseudocapacitive behaviors are mainly due to the unique hierarchical core-shell structure and the synergistic effect of combining ZnO nanorod arrays and NiO/MoO2 composite nanosheets. This novel hierarchical core-shell structure shows promise for use in next-generation supercapacitors.

  13. Influence of helium-ion bombardment on the optical properties of ZnO nanorods/p-GaN light-emitting diodes

    Science.gov (United States)

    Alvi, Naveed Ul Hassan; Hussain, Sajjad; Jensen, Jen; Nur, Omer; Willander, Magnus

    2011-12-01

    Light-emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods grown by vapor-liquid-solid catalytic growth method were irradiated with 2-MeV helium (He+) ions. The fabricated LEDs were irradiated with fluencies of approximately 2 × 1013 ions/cm2 and approximately 4 × 1013 ions/cm2. Scanning electron microscopy images showed that the morphology of the irradiated samples is not changed. The as-grown and He+-irradiated LEDs showed rectifying behavior with the same I-V characteristics. Photoluminescence (PL) measurements showed that there is a blue shift of approximately 0.0347 and 0.082 eV in the near-band emission (free exciton) and green emission of the irradiated ZnO nanorods, respectively. It was also observed that the PL intensity of the near-band emission was decreased after irradiation of the samples. The electroluminescence (EL) measurements of the fabricated LEDs showed that there is a blue shift of 0.125 eV in the broad green emission after irradiation and the EL intensity of violet emission approximately centered at 398 nm nearly disappeared after irradiations. The color-rendering properties show a small decrease in the color-rendering indices of 3% after 2 MeV He+ ions irradiation.

  14. Effect of Nb-doped TiO{sub 2} on nanocomposited aligned ZnO nanorod/TiO{sub 2}:Nb for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Saurdi, I., E-mail: saurdy788@gmail.com; Ishak, A. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); UiTM Sarawak Kampus Kota Samarahan Jalan Meranek, Sarawak (Malaysia); Shafura, A. K.; Azhar, N. E. A.; Mamat, M. H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); Malek, M. F.; Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM),40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), (Centre for Nano-Science and Nano-Technology), Institute of Science, Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Alrokayan, A. H. Salman; Khan, Haseeb A. [Department of Biochemistry, College of Science, Bldg. 5, King Saud University (KSU) P.O: 2455 Riyadh 1145 (Saudi Arabia)

    2016-07-06

    The Nb-doped TiO{sub 2} films were deposited on glass substrate at different Nb concentrations of 0 at.%, 1 at.%, 3 at.%, 5 at.% and 7 at.%, respectively and their electrical and structural properties were investigated. Subsequently, the Nb-doped TiO{sub 2} films were deposited on top of aligned ZnO Nanorod on ITO glass substrates using spin coating technique. The nanocomposited aligned ZnO nanorod/Nb-doped TiO{sub 2} (TiO{sub 2}:Nb) were coated with different Nb concentrations of 0 at.%, 1 at.%, 3 at.%, 5 at.% and 7 at.%, respectively. The Dye-sensitized solar cells were fabricated from the nanocomposited aligned ZnO nanorod/TiO{sub 2}:Nb photoanodes and their effects on the performance of the DSSCs were investigated. From the solar simulator measurement of DSSC the solar energy conversion efficiency (η) of 5.376% under AM 1.5 was obtained for the ZnO nanorod/TiO{sub 2}:Nb-5at.%.

  15. Origin of the near-band-edge photoluminescence in ZnO nanorods realised by vapour phase epitaxy and aqueous chemical growth

    Energy Technology Data Exchange (ETDEWEB)

    Bekeny, C.; Hilker, B.; Wischmeier, L.; Voss, T. [IFP, University of Bremen, P.O Box 330440, 28334 Bremen (Germany); Postels, B.; Mofor, A.; Bakin, Andrey; Waag, A. [IHT, TU Braunschweig, P.O Box 3329, 38023 Braunschweig (Germany)

    2007-07-01

    Well established high temperature growth techniques like the vapourliquid-solid (VLS: 1100 C) and vapour-phase-epitaxy (VPE: 800 C) have been successfully optimized while the low-temperature aqueous chemical growth (ACG: 90 C) is being extended to yield large-scale high quality ZnO nanorods. Here, a detailed and systematic photoluminescence (PL) study is presented to understand the microscopic processes responsible for the near-band-edge (NBE) emission in nanorods obtained from these processes. For the ACG samples, the as-grown nanorods show relatively broad NBE emission (15 meV) attributed to the presence of large donor densities. After annealing in various atmospheres at {proportional_to}800 C, a significant reduction of the linewidth ({proportional_to}4 meV) and even the appearance of relatively sharp excitonic transitions is explained by the drastic reduction of the donor density. In contrast, the as-grown VPE and VLS samples exhibit well-resolved and sharp peaks resulting from exciton-related transitions. There is a shift in the room-temperature PL peak for VLS and VPE samples and is shown to result from contributions of the free exciton peak, its first and second order phonon replicas and not due to quantum confinement and or laser heating as assumed in literature.

  16. Investigation of photocalalytic activity of ZnO prepared by spray pyrolis with various precursors

    International Nuclear Information System (INIS)

    Bourfaa, F; Lamri Zeggar, M; A, A; Aida, M S; Attaf, N

    2016-01-01

    Semiconductor photocatalysts such as ZnO has attracted much attention in recent years due to their various applications for the degradation of organic pollutants in water, air and in dye sensitized photovoltaic solar cell. In the present work, ZnO thin films were prepared by ultrasonic spray pyrolysis by using different precursors namely: acetate, chloride and zinc nitrate in order to investigate their influence on ZnO photocatalytic activity. The films crystalline structure was studied by mean of X- ray diffraction measurements (XRD) and the films surface morphology by Scanning Electron Microscopy (SEM). The films optical properties were studied by mean of UV-visible spectroscopy. The prepared films were tested for the degradation of the red reactive dye largely used in textile industry. As a result, we found that the zinc nitrate is the best precursor to prepare ZnO thin films suitable for a good photocatalytic activity. (paper)

  17. Water-repellent coatings prepared by modification of ZnO nanoparticles

    Science.gov (United States)

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

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

  18. Nonenzymatic flexible field-effect transistor based glucose sensor fabricated using NiO quantum dots modified ZnO nanorods.

    Science.gov (United States)

    Jung, Da-Un-Jin; Ahmad, Rafiq; Hahn, Yoon-Bong

    2018-02-15

    Herein, we fabricated nonenzymatic flexible field-effect transistor (f-FET) based glucose sensor using nickel oxide quantum dots (NiO QDs) modified zinc oxide nanorods (ZnO NRs). The ZnO NRs surfaces were coated with NiO QDs using radio frequency (RF) magnetron sputtering to enhance the electrocatalytic feature and the surface area of ZnO NRs. Under physiological conditions (pH 7.4), the nonenzymatic f-FET glucose sensor shows two linear ranges of 0.001-10mM and 10-50mM with the high sensitivity of 13.14μAcm -2 mM -1 and 7.31μAcm -2 mM -1 , respectively, along with good selectivity, stability and repeatability during glucose detection. The examination of human whole blood and serum samples reveal that the nonenzymatic f-FET based glucose sensor is capable of measuring glucose concentration efficiently in the presence of interfering species and thus can be offered as a promising device for further applications in clinical and non-clinical fields. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Passivating ZnO Surface States by C60 Pyrrolidine Tris-Acid for Hybrid Solar Cells Based on Poly(3-hexylthiophene/ZnO Nanorod Arrays

    Directory of Open Access Journals (Sweden)

    Peng Zhong

    2017-12-01

    Full Text Available Construction of ordered electron acceptors is a feasible way to solve the issue of phase separation in polymer solar cells by using vertically-aligned ZnO nanorod arrays (NRAs. However, the inert charge transfer between conducting polymer and ZnO limits the performance enhancement of this type of hybrid solar cells. In this work, a fullerene derivative named C60 pyrrolidine tris-acid is used to modify the interface of ZnO/poly(3-hexylthiophene (P3HT. Results indicate that the C60 modification passivates the surface defects of ZnO and improves its intrinsic fluorescence. The quenching efficiency of P3HT photoluminescence is enhanced upon C60 functionalization, suggesting a more efficient charge transfer occurs across the modified P3HT/ZnO interface. Furthermore, the fullerene modified hybrid solar cell based on P3HT/ZnO NRAs displays substantially-enhanced performance as compared to the unmodified one and the devices with other modifiers, which is contributed to retarded recombination and enhanced exciton separation as evidenced by electrochemical impedance spectra. Therefore, fullerene passivation is a promising method to ameliorate the connection between conjugated polymers and metal oxides, and is applicable in diverse areas, such as solar cells, transistors, and light-emitting dioxides.

  20. MEH-PPV and PCBM Solution Concentration Dependence of Inverted-Type Organic Solar Cells Based on Eosin-Y-Coated ZnO Nanorod Arrays

    Directory of Open Access Journals (Sweden)

    Riski Titian Ginting

    2013-01-01

    Full Text Available The influence of polymer solution concentration on the performance of chlorobenzene- (CB- and chloroform- (CF- based inverted-type organic solar cells has been investigated. The organic photoactive layers consisted of poly(2-methoxy-5-(2-ethyl hexyloxy-1,4-phenylenevinylene (MEH-PPV and (6,6-phenyl C61 butyric acid methyl ester (PCBM were spin coated from CF with concentrations of 4, 6, and 8 mg/mL and from CB with concentrations of 6, 8, and 10 mg/mL onto Eosin-Y-coated ZnO nanorod arrays (NRAs. Fluorine doped tin oxide (FTO and silver (Ag were used as electron collecting electrode and hole collecting electrode, respectively. Experimental results showed that the short circuit current density and power conversion efficiency increased with decrease of solution concentration for both CB and CF devices, which could be attributed to reducing charge recombination in thinner photoactive layer and larger contact area between the rougher photoactive layer and Ag contact. However, the open circuit voltage decreased with decreasing solution concentration due to increase of leakage current from ZnO NRAs to Ag as the ZnO NRAs were not fully covered by the polymer blend. The highest power conversion efficiencies of 0.54 ± 0.10% and 0.87 ± 0.15% were achieved at the respective lowest solution concentrations of CB and CF.

  1. Piezoelectric and opto-electrical properties of silver-doped ZnO nanorods synthesized by low temperature aqueous chemical method

    Directory of Open Access Journals (Sweden)

    E. S. Nour

    2015-07-01

    Full Text Available In this paper, we have synthesized Zn1−xAgxO (x = 0, 0.03, 0.06, and 0.09 nanorods (NRs via the hydrothermal method at low temperature on silicon substrate. The characterization and comparison between the different Zn1−xAgxO samples, indicated that an increasing Ag concentration from x = 0 to a maximum of x = 0.09; All samples show a preferred orientation of (002 direction with no observable change of morphology. As the quantity of the Ag dopant was changed, the transmittances, as well as the optical band gap were decreased. X-ray photoelectron spectroscopy data clearly indicate the presence of Ag in ZnO crystal lattice. A nanoindentation-based technique was used to measure the effective piezo-response of different concentrations of Ag for both direct and converse effects. The value of the piezoelectric coefficient (d33 as well as the piezo potential generated from the ZnO NRs and Zn1−xAgxO NRs was found to decrease with the increase of Ag fraction. The finding in this investigation reveals that Ag doped ZnO is not suitable for piezoelectric energy harvesting devices.

  2. A novel low-temperature chemical solution route for straight and dendrite-like ZnO nanostructures

    International Nuclear Information System (INIS)

    Zhang Hui; Du Ning; Wu Jianbo; Ma, Xiangyang; Yang Deren; Zhang Xiaobin; Yang Zhiqing

    2007-01-01

    The straight and dendrite-like growths of ZnO have been completely and simply controlled by the status of ZnO seed instead of surfactant, template, oriented attachment, and ZnO buffer layer on the substrate in the chemical reaction synthesis of ZnO nanostructures. The monodisperse ZnO seeds, which are prepared by in situ quickly injecting the cool mixed zinc acetate and potassium hydrate ethanol solution into the hot matrix aqueous solution of zinc nitrate hydrate and diethylenetriamine at 95 deg. C, improve the straight growth and lots of uniform, straight, and single-crystalline ZnO nanorods with about 20-30 nm in diameter and 300 nm in length are achieved. While, the aggregated ZnO seeds, which are prepared by dropwise adding potassium hydrate ethanol solution into zinc acetate ethanol solution at 60 deg. C for 3 h, result in the dendrite-like growth and the bur-like ZnO nanostructures consisting of hundreds of nanorods with about 30-50 nm in diameter and several micrometers in length are formed. Furthermore, the approach presented here provides a simple, low-cost, environmental-friendly and high efficiency route to synthesize the high quality ZnO nanorods and bur-like ZnO nanostructures

  3. Synthesis of ZnO nanorod–nanosheet composite via facile hydrothermal method and their photocatalytic activities under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Wai Kian [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Abdul Razak, Khairunisak; Lockman, Zainovia [School of Materials and Mineral Resources, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Kawamura, Go; Muto, Hiroyuki [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@ee.tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan)

    2014-03-15

    ZnO composite films consisting of ZnO nanorods and nanosheets were prepared by low-temperature hydrothermal processing at 80 °C on seeded glass substrates. The seed layer was coated on glass substrates by sol–gel dip-coating and pre-heated at 300 °C for 10 min prior to hydrothermal growth. The size of the grain formed after pre-heat treatment was ∼40 nm. A preferred orientation seed layer at the c-axis was obtained, which promoted vertical growth of the ZnO nanorod arrays and formation of the ZnO nanosheets. X-ray diffraction patterns and high-resolution transmission electron microscope (HR-TEM) images confirmed that the ZnO nanorods and nanosheets consist of single crystalline and polycrystalline structures, respectively. Room temperature photoluminescence spectra of the ZnO nanorod–nanosheet composite films exhibited band-edge ultraviolet (UV) and visible emission (blue and green) indicating the formation of ZnO crystals with good crystallinity and are supported by Raman scattering results. The formation of one-dimensional (1D) ZnO nanorod arrays and two-dimensional (2D) ZnO nanosheet films using seeded substrates in a single low-temperature hydrothermal step would be beneficial for realization of device applications that utilize substrates with limited temperature stability. The ZnO nanorods and nanosheets composite structure demonstrated higher photocatalytic activity during degradation of aqueous methylene blue under visible-light irradiation. -- Graphical abstract: Schematic illustration of ZnO nanorod–nanosheet composite structure formation by hydrothermal at low-temperature of 80 °C against time. Highlights: • Novel simultaneous formation of ZnO nanorods and nanosheets composite structure. • Facile single hydrothermal step formation at low-temperature. • Photoluminescence showed ultraviolet and visible emission. • Feasible application on substrates with low temperature stability. • Improved photocatalytic activity under visible

  4. Effect of indium on photovoltaic property of n-ZnO/p-Si heterojunction device prepared using solution-synthesized ZnO nanowire film

    Science.gov (United States)

    Kathalingam, Adaikalam; Kim, Hyun-Seok; Park, Hyung-Moo; Valanarasu, Santiyagu; Mahalingam, Thaiyan

    2015-01-01

    Preparation of n-ZnO/p-Si heterostructures using solution-synthesized ZnO nanowire films and their photovoltaic characterization is reported. The solution-grown ZnO nanowire film is characterized using scanning electron microscope, electron dispersive x-ray, and optical absorption studies. Electrical and photovoltaic properties of the fabricated heterostructures are studied using e-beam-evaporated aluminum as metal contacts. In order to use transparent contact and to simultaneously collect the photogenerated carriers, sandwich-type solar cells were fabricated using ZnO nanorod films grown on p-silicon and indium tin oxide (ITO) coated glass as ITO/n-ZnO NR/p-Si. The electrical properties of these structures are analyzed from current-voltage (I-V) characteristics. ZnO nanowire film thickness-dependent photovoltaic properties are also studied. Indium metal was also deposited over the ZnO nanowires and its effects on the photovoltaic response of the devices were studied. The results demonstrated that all the samples exhibit a strong rectifying behavior indicating the diode nature of the devices. The sandwich-type ITO/n-ZnO NR/p-Si solar cells exhibit improved photovoltaic performance over the Al-metal-coated n-ZnO/p-Si structures. The indium deposition is found to show enhancement in photovoltaic behavior with a maximum open-circuit voltage (Voc) of 0.3 V and short-circuit current (Isc) of 70×10-6 A under ultraviolet light excitation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-28

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

  6. A sol-gel method for preparing ZnO quantum dots with strong blue emission

    International Nuclear Information System (INIS)

    Chen Zhong; Li Xiaoxia; Du Guoping; Chen Nan; Suen, Andy Y.M.

    2011-01-01

    ZnO quantum dots (QDs) with strong blue emission have been successfully synthesized by sol-gel method, and their crystal structures, sizes, and photoluminescence properties were characterized by X-ray diffractometer, scanning electron microscope, and ultraviolet-visible spectroscopy. It has been found that ZnO QDs had a hexagonal wurtzite crystal structure, and their average diameter was about 16.0-32.2 nm. Both the reaction time and temperature were found to have a strong influence on the average size and photoluminescence properties of ZnO QDs. Longer reaction time and higher reaction temperature resulted in larger average size for ZnO QDs. It has been shown that at reaction temperature 60 deg. C the emission intensity for ZnO QDs increased first with reaction time before 7 h and then decreased after 7 h. For the same reaction time 7 h, ZnO QDs synthesized at 60 deg. C showed the strongest emission intensity. It was found that annealing in nitrogen, vacuum, and air all resulted in an increase of the size of ZnO QDs and a reduction in their photoluminescence. The dependence of the size and properties of ZnO QDs on the reaction parameters as well as the annealing conditions has been discussed. - Highlights: → ZnO quantum dots (QDs) with strong blue emission were prepared by sol-gel method. → ZnO QDs had a pure spectral blue with the chromaticity coordinates (0.166, 0.215). → Optimal reaction time and temperature were 7 h and 60 deg. C, respectively.

  7. Facile preparation of MnO2 nanorods and evaluation of their supercapacitive characteristics

    Science.gov (United States)

    Aghazadeh, Mustafa; Asadi, Maryam; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

    2016-02-01

    The first time pulsed base (OH-) electrogeneration to the cathodic electrodeposition of MnO2 in nitrate bath was applied and MnO2 nanorods were obtained. The deposition experiments were performed under a pulse current mode with typical on-times and off-times (ton = 10 ms and toff = 50 ms) and a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterization with XRD and FTIR revealed that the prepared MnO2 is composed of both α and γ phases. Morphological evaluations through SEM and TEM revealed that the prepared MnO2 contains nanorods of relative uniform structures (with an average diameter of 50 nm). The electrochemical measurements through cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures reveal an excellent capacitive behavior with specific capacitance values of 242, 167 and 98 F g-1 under the applied current densities of 2, 5 and 10 A g-1, respectively. Also, excellent long-term cycling stabilities of 94.8%, 89.1%, and 76.5% were observed after 1000 charge-discharge cycles at the current densities of 2, 5 and 10 A g-1.

  8. Natural Biowaste-Cocoon-Derived Granular Activated Carbon-Coated ZnO Nanorods: A Simple Route To Synthesizing a Core-Shell Structure and Its Highly Enhanced UV and Hydrogen Sensing Properties.

    Science.gov (United States)

    Saravanan, Adhimoorthy; Huang, Bohr-Ran; Kathiravan, Deepa; Prasannan, Adhimoorthy

    2017-11-15

    Granular activated carbon (GAC) materials were prepared via simple gas activation of silkworm cocoons and were coated on ZnO nanorods (ZNRs) by the facile hydrothermal method. The present combination of GAC and ZNRs shows a core-shell structure (where the GAC is coated on the surface of ZNRs) and is exposed by systematic material analysis. The as-prepared samples were then fabricated as dual-functional sensors and, most fascinatingly, the as-fabricated core-shell structure exhibits better UV and H 2 sensing properties than those of as-fabricated ZNRs and GAC. Thus, the present core-shell structure-based H 2 sensor exhibits fast responses of 11% (10 ppm) and 23.2% (200 ppm) with ultrafast response and recovery. However, the UV sensor offers an ultrahigh photoresponsivity of 57.9 A W -1 , which is superior to that of as-grown ZNRs (0.6 A W -1 ). Besides this, switching photoresponse of GAC/ZNR core-shell structures exhibits a higher switching ratio (between dark and photocurrent) of 1585, with ultrafast response and recovery, than that of as-grown ZNRs (40). Because of the fast adsorption ability of GAC, it was observed that the finest distribution of GAC on ZNRs results in rapid electron transportation between the conduction bands of GAC and ZNRs while sensing H 2 and UV. Furthermore, the present core-shell structure-based UV and H 2 sensors also well-retained excellent sensitivity, repeatability, and long-term stability. Thus, the salient feature of this combination is that it provides a dual-functional sensor with biowaste cocoon and ZnO, which is ecological and inexpensive.

  9. ZnO Nanorods on a LaAlO 3 -SrTiO 3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties

    KAUST Repository

    Bera, Ashok

    2015-12-28

    Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The influence of annealing temperature on the interface and photovoltaic properties of CdS/CdSe quantum dots sensitized ZnO nanorods solar cells.

    Science.gov (United States)

    Qiu, Xiaofeng; Chen, Ling; Gong, Haibo; Zhu, Min; Han, Jun; Zi, Min; Yang, Xiaopeng; Ji, Changjian; Cao, Bingqiang

    2014-09-15

    Arrays of ZnO/CdS/CdSe core/shell nanocables with different annealing temperatures have been investigated for CdS/CdSe quantum dots sensitized solar cells (QDSSCs). CdS/CdSe quantum dots were synthesized on the surface of ZnO nanorods that serve as the scaffold via a simple ion-exchange approach. The uniform microstructure was verified by scanning electron microscope and transmission electron microscope. UV-Visible absorption spectrum and Raman spectroscopy analysis indicated noticeable influence of annealing temperature on the interface structural and optical properties of the CdS/CdSe layers. Particularly, the relationship between annealing temperatures and photovoltaic performance of the corresponding QDSSCs was investigated employing photovoltaic conversion, quantum efficiency and electrochemical impedance spectra. It is demonstrated that higher cell efficiency can be obtained by optimizing the annealing temperature through extending the photoresponse range and improving QD layer crystal quality. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Central composite design and genetic algorithm applied for the optimization of ultrasonic-assisted removal of malachite green by ZnO Nanorod-loaded activated carbon

    Science.gov (United States)

    Ghaedi, M.; Azad, F. Nasiri; Dashtian, K.; Hajati, S.; Goudarzi, A.; Soylak, M.

    2016-10-01

    Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20 mg g- 1) is sufficient for the rapid removal of high amount of MG dye in short time (3.99 min).

  12. High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M=Ag, Cd and Ni) heterojunction based ultraviolet photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Echresh, Ahmad, E-mail: ahmadechresh@gmail.com [Department of Science and Technology, Physical Electronics and Nanotechnology Division, Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden); Echresh, Mohammad [Department of Physics, Sanati Hoveizeh University, Ahvaz (Iran, Islamic Republic of); Khranovskyy, Volodymyr [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-5818358183 Linköping (Sweden); Nur, Omer; Willander, Magnus [Department of Science and Technology, Physical Electronics and Nanotechnology Division, Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden)

    2016-10-15

    The thermal evaporation method has been used to deposit p-type NiO thin film, which was combined with hydrothermally grown n-type pure and M-doped ZnO nanorods (M=Ag, Cd and Ni) to fabricate a high performance p-n heterojunction ultraviolet photodiodes. The fabricated photodiodes show high rectification ratio and relatively low leakage current. The p-NiO/n-Zn{sub 0.94}Ag{sub 0.06}O heterojunction photodiode displays the highest photocurrent gain (~1.52×10{sup 4}), a photoresponsivity of ~4.48×10{sup 3} AW{sup −1} and a photosensitivity of ~13.56 compared with the other fabricated photodiodes. The predominated transport mechanisms of the p-n heterojunction ultraviolet photodiodes at low and high applied forward bias may be recombination-tunneling and space charge limited current, respectively.

  13. ZnO Nanorods on a LaAlO 3 -SrTiO 3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties

    KAUST Repository

    Bera, Ashok; Lin, Weinan; Yao, Yingbang; Ding, Junfeng; Lourembam, James; Wu, Tao

    2015-01-01

    Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. MOVPE gallium-nitride nanostructures fabricated on ZnO nanorod templates grown from aqueous chemical solution

    Energy Technology Data Exchange (ETDEWEB)

    Fuendling, Soenke; Li Shunfeng; Postels, Bianca; Al-Suleiman, Mohamed; Wehmann, Hergo-Heinrich; Bakin, Andrey; Waag, Andreas, E-mail: s.fuendling@tu-bs.de [Institut fuer Halbleitertechnik, Technische Universitaet Braunschweig, 38096 Braunschweig (Germany)

    2009-11-15

    Concerning optoelectronic devices fabricated by epitaxial methods, the combination of ZnO and GaN has promising aspects regarding their good optical properties and a relatively good lattice matching between both as compared to other foreign substrates like sapphire or silicon. Moreover ZnO nanopillar arrays may serve as a template for GaN nanopillar fabrication or for high quality GaN layers by lateral overgrowth of the ZnO nanopillars. In this work, we investigate the combination of two very different growth methods - aqueous chemical low temperature growth (ACG) for the ZnO nanopillar templates on silicon substrates and metalorganic vapor phase epitaxy (MOVPE) for the GaN overgrowth - in order to show to which extent the very cost efficient ZnO templates suit the high demands of GaN MOVPE. By a combination of annealing and photoluminescence experiments we show that the properties of the heterostructures change significantly with temperature.

  15. Structural and optical properties of Co-doped ZnO nanocrystallites prepared by a one-step solution route

    International Nuclear Information System (INIS)

    Li Ping; Wang Sha; Li Jibiao; Wei Yu

    2012-01-01

    Zinc oxide (ZnO) nanocrystallites with different Co-doping levels were successfully synthesized by a simple one-step solution route at low temperature (95 deg. C) in this study. The structure and morphology of the samples thus obtained were characterized by XRD, EDS, XPS and FESEM. Results show that cobalt ions, in the oxidation state of Co 2+ , replace Zn 2+ ions in the ZnO lattice without changing its wurtzite structure. The dopant content varies from 0.59% to 5.39%, based on Co-doping levels. The pure ZnO particles exhibit well-defined 3D flower-like morphology with an average size of 550 nm, while the particles obtained after Co-doping are mostly cauliflower-like nanoclusters with an average size of 120 nm. Both the flower-like pure ZnO and the cauliflower-like Co:ZnO nanoclusters are composed of densely arrayed nanorods. The optical properties of the ZnO nanocrystallites following Co-doping were also investigated by UV-Visible absorption and Photoluminescence spectra. Our results indicate that Co-doping can change the energy-band structure and effectively adjust the luminescence properties of ZnO nanocrystallites. - Highlights: → Co-doped ZnO nanocrystallites were synthesized via a simple one-step solution route. → Co 2+ ions incorporated into the ZnO lattice without changing its wurtzite structure. → Co-doping changed the energy band structure of ZnO. → Co-doping effectively adjusted the luminescence properties of ZnO nanocrystallites.

  16. Structural and optical properties of Co-doped ZnO nanocrystallites prepared by a one-step solution route

    Energy Technology Data Exchange (ETDEWEB)

    Li Ping, E-mail: lipingchina@yahoo.com.cn [Provincial Key Laboratory of Inorganic Nanomaterials, School of Chemistry and Materials Science, Hebei Normal University, 113 Yuhua Road, Shijiazhuang 050016, Hebei (China); Wang Sha; Li Jibiao; Wei Yu [Provincial Key Laboratory of Inorganic Nanomaterials, School of Chemistry and Materials Science, Hebei Normal University, 113 Yuhua Road, Shijiazhuang 050016, Hebei (China)

    2012-01-15

    Zinc oxide (ZnO) nanocrystallites with different Co-doping levels were successfully synthesized by a simple one-step solution route at low temperature (95 deg. C) in this study. The structure and morphology of the samples thus obtained were characterized by XRD, EDS, XPS and FESEM. Results show that cobalt ions, in the oxidation state of Co{sup 2+}, replace Zn{sup 2+} ions in the ZnO lattice without changing its wurtzite structure. The dopant content varies from 0.59% to 5.39%, based on Co-doping levels. The pure ZnO particles exhibit well-defined 3D flower-like morphology with an average size of 550 nm, while the particles obtained after Co-doping are mostly cauliflower-like nanoclusters with an average size of 120 nm. Both the flower-like pure ZnO and the cauliflower-like Co:ZnO nanoclusters are composed of densely arrayed nanorods. The optical properties of the ZnO nanocrystallites following Co-doping were also investigated by UV-Visible absorption and Photoluminescence spectra. Our results indicate that Co-doping can change the energy-band structure and effectively adjust the luminescence properties of ZnO nanocrystallites. - Highlights: > Co-doped ZnO nanocrystallites were synthesized via a simple one-step solution route. > Co{sup 2+} ions incorporated into the ZnO lattice without changing its wurtzite structure. > Co-doping changed the energy band structure of ZnO. > Co-doping effectively adjusted the luminescence properties of ZnO nanocrystallites.

  17. All-solid, flexible solar textiles based on dye-sensitized solar cells with ZnO nanorod arrays on stainless steel wires

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Youngjin [Department of Clothing and Textiles, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Park, Jung Tae; Koh, Jong Kwan [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Jong Hak, E-mail: jonghak@yonsei.ac.kr [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Eunae, E-mail: eakim@yonsei.ac.kr [Department of Clothing and Textiles, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

    2013-10-01

    Highlights: • All-solid, flexible solar textile fabricated with DSSCs is demonstrated. • DSSCs woven into a satin structure and transparent PET film are used. • Solar textile showed a high efficiency of 2.57%. -- Abstract: An all-solid, flexible solar textile fabricated with dye-sensitized solar cells (DSSCs) woven into a satin structure and transparent poly(ethylene terephthalate) (PET) film was demonstrated. A ZnO nanorod (NR) vertically grown from fiber-type conductive stainless steel (SS) wire was utilized as a photoelectrode, and a Pt-coated SS wire was used as a counter electrode. A graft copolymer, i.e. poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) was synthesized via atom transfer radical polymerization (ATRP) and used as a solid electrolyte. The conditions for the growth of ZnO NR and sufficient dye loading were investigated to improve cell performance. The adhesion of PET films to DSSCs resulted in physical stability improvements without cell performance loss. The solar textile with 10 × 10 wires exhibited an energy conversion efficiency of 2.57% with a short circuit current density of 20.2 mA/cm{sup 2} at 100 mW/cm{sup 2} illumination, which is the greatest account of an all-solid, ZnO-based flexible solar textile. DSSC textiles with woven structures are applicable to large-area, roll-to-roll processes.

  18. Annealing effects on the optical and morphological properties of ZnO nanorods on AZO substrate by using aqueous solution method at low temperature.

    Science.gov (United States)

    Hang, Da-Ren; Islam, Sk Emdadul; Sharma, Krishna Hari; Kuo, Shiao-Wei; Zhang, Cheng-Zu; Wang, Jun-Jie

    2014-01-01

    Vertically aligned ZnO nanorods (NRs) on aluminum-doped zinc oxide (AZO) substrates were fabricated by a single-step aqueous solution method at low temperature. In order to optimize optical quality, the effects of annealing on optical and structural properties were investigated by scanning electron microscopy, X-ray diffraction, photoluminescence (PL), and Raman spectroscopy. We found that the annealing temperature strongly affects both the near-band-edge (NBE) and visible (defect-related) emissions. The best characteristics have been obtained by employing annealing at 400°C in air for 2 h, bringing about a sharp and intense NBE emission. The defect-related recombinations were also suppressed effectively. However, the enhancement decreases with higher annealing temperature and prolonged annealing. PL study indicates that the NBE emission is dominated by radiative recombination associated with hydrogen donors. Thus, the enhancement of NBE is due to the activation of radiative recombinations associated with hydrogen donors. On the other hand, the reduction of visible emission is mainly attributed to the annihilation of OH groups. Our results provide insight to comprehend annealing effects and an effective way to improve optical properties of low-temperature-grown ZnO NRs for future facile device applications.

  19. Preparation of Gelatin coated hydroxyapatite nanorods and the stability of its aqueous colloidal

    International Nuclear Information System (INIS)

    Chen Minfang; Tan Junjun; Lian Yuying; Liu Debao

    2008-01-01

    This paper describes a novel process for preparing Gelatin coated hydroxyapatite (HAp) nanorods to improve the stability of its aqueous colloid. As Gelatin is a typical protein with abundant hydroxyls, carboxys and imines, it is a very effective functional group to attach onto the surfaces of the HAp particles. Our data show that the Gelatin layer firmly coated on the hydroxyapatite nanorods, and their structure and interfacial chemical bonding have been studied using various techniques, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HRTEM), differential thermal analysis (DTA) and thermal gravimetric analysis (TGA). The reaction temperature, pH, amount of Gelatin, and Ca/P molar ratio in the material determine the quality of Gelatin coating and the stability of the HAp in aqueous solution. Moreover, an interesting phenomenon was found that the Gelatin coated HAp sediment separated by centrifugal was easily dispersed in water and forms HAp aqueous suspension. The suspension was stable for more than 24 h

  20. Investigation of the Influence of the As-Grown ZnO Nanorods and Applied Potentials on an Electrochemical Sensor for In-Vitro Glucose Monitoring

    Directory of Open Access Journals (Sweden)

    Mohammed Marie

    2017-01-01

    Full Text Available The influence of the as-grown zinc oxide nanorods (ZnO NRs on the fabricated electrochemical sensor for in vitro glucose monitoring were investigated. A direct growth of ZnO NRs was performed on the Si/SiO2/Au electrode, using hydrothermal and sol-gel techniques at low temperatures. The structure, consisting of a Si/SiO2/Au/GOx/Nafion membrane, was considered as a baseline, and it was tested under several applied potential 0.1–0.8 V. The immobilized working electrode, with GOx and a nafion membrane, was characterized amperometrically using a source meter Keithely 2410, and an electrochemical impedance Gamry potentiostat. The sensor exhibited the following: a high sensitivity of ~0.468 mA/cm2 mM, a low detection limit in the order of 166.6 µM, and a fast and sharp response time of around 2 s. The highest sensitivity and the lowest limit of detection were obtained at 0.4 volt, after the growth of ZnO NRs. The highest net sensitivity was obtained after subtracting the sensitivity of the baseline, and it was in the order of 0.315 mA/cm2·mM. The device was tested with a range of glucose concentrations from 1–10 mM, showing a linear line from 3–8 mM, and the device was saturated after exceeding high concentrations of glucose. Such devices can be used for in vitro glucose monitoring, since glucose changes can be accurately detected.

  1. Monolithic Au/CeO2 nanorod framework catalyst prepared by dealloying for low-temperature CO oxidation

    Science.gov (United States)

    Zhang, Xiaolong; Duan, Dong; Li, Guijing; Feng, Wenjie; Yang, Sen; Sun, Zhanbo

    2018-03-01

    Monolithic Au/CeO2 nanorod frameworks (NFs) with porous structure were prepared by dealloying melt-spun Al89.7Ce10Au0.3 ribbons. After calcination in O2, a 3D Au/CeO2 NF catalyst with large surface area was obtained and used for low-temperature CO oxidation. The small Au clusters/nanoparticles (NPs) were in situ supported and highly dispersed on the nanorod surface, creating many nanoscale contact interfaces. XPS results demonstrated that high-concentration oxygen vacancy and Au δ+/Au0 co-existed in the calcined sample. The Au/CeO2 nanorod catalyst calcined at 400 °C exhibited much higher catalytic activity for CO oxidation compared with the dealloyed sample and bare CeO2 nanorods. Moreover, its complete reaction temperature was as low as 91 °C. The designed Au/CeO2 NF catalyst not only possessed extreme sintering resistance but also exhibited high performance owing to the enhanced interaction between the Au clusters/NPs and CeO2 nanorod during calcination.

  2. Sims Characterisation of ZnO Layer Prepared By Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Andrej Vincze

    2005-01-01

    Full Text Available New material development requires new technologies to create and prepare basic material for semiconductor industry and device applications. Materials have given properties, which exhibit particulary small tolerances. One of the most important and promising material is recently ZnO. ZnO has specific properties for near UV emission and absorption optical devices. The pulsed laser deposition (PLD is one of the methods to prepare this type of material. The aim of this paper is to compare properties of ZnO layers deposited from pure Zn target in oxygen atmosphere and the analysis of their surface properties by secondary ion mass spectroscopy (SIMS, atomic force microscopy (AFM and scanning electron microscopy (SEM.

  3. Synthesis and in-depth analysis of highly ordered yttrium doped hydroxyapatite nanorods prepared by hydrothermal method and its mechanical analysis

    International Nuclear Information System (INIS)

    Nathanael, A. Joseph; Mangalaraj, D.; Hong, S.I.; Masuda, Y.

    2011-01-01

    In this study, undoped and yttrium (Y) doped nanocrystalline hydroxyapatite crystals were synthesized by the hydrothermal method at 180 °C for 24 h. Highly ordered and oriented hydroxyapatite (HAp) nanorods were prepared by yttrium doping and their nanostructure and physical properties were compared with those of undoped HAp rods. FESEM images showed that the doping with Y ions reduced the diameter (from 25 nm to 15 nm) and increased the length (from 95 nm to 115 nm) of the synthesized rods. The aspect ratio of the undoped and Y-doped nanorods were calculated to be 4.303 (SD = 0.0959) and 7.61 (SD = 0.0355), respectively. Specific surface area (SSA) analysis showed that SSA also increased from 66.74 m 2 /g to 68.57 m 2 /g with the addition of yttrium. Y-doped HAp nanorod reinforced HMWPE composites displayed the better mechanical performance than those reinforced with pure HAp nanorods. The possible strengthening of nanorods and the increase of SSA due to the reduction in the size of nanorods in the presence of yttrium may have contributed to the strengthening of Y-doped HAp/HMWPE composites. - Graphical Abstract: Highly ordered and oriented yttrium doped hydroxyapatite (HAp) nanorods were prepared by hydrothermal method. For undoped HAp the average length of the nanorod is 95 nm with mean diameter of 24 nm and for a Y doped nanorod the average length is ∼ 115 nm and the mean diameter is 15 nm. Mechanical analysis was carried out by polymer/nanoparticle composite method. Highlights: ► Yttrium doped hydroxyapatite nanorods were prepared by hydrothermal method. ► The nanorods have highly uniform size distribution. ► Yttrium substitution and nanostructure formation was confirmed by careful analysis. ► Mechanical strength was analyzed by polymer nanoparticle reinforcement method.

  4. Growth of novel ZnO nanostructures by soft chemical routes

    International Nuclear Information System (INIS)

    Saravana Kumar, R.; Sathyamoorthy, R.; Matheswaran, P.; Sudhagar, P.; Kang, Yong Soo

    2010-01-01

    Research highlights: Fabrication of diverse ZnO nanostructures through soft chemical routes is both fundamentally interesting and technologically important. Accordingly, in the present work novel ZnO nanostructures namely nanorods/nanospines were grown on glass substrate by integrating SILAR and CBD techniques. This simple approach not only would lead to the development of an effective and commercial growth process for diverse ZnO nanostructures, but also lead to the large-scale preparation of other nanomaterials for many important applications in nanotechnology. - Abstract: We explore a facile route to prepare one-dimensional (1D) ZnO nanostructures including nanorods/nanospines on glass substrates by integrating inexpensive successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) methods. The effect of seed layer on the growth and morphology of the ZnO nanostructures was investigated. Accordingly, the surface modification of the seed layer prepared by SILAR was carried out by employing two different drying processes namely (a) allowing the hot substrate to cool for certain period of time before immersing in the ion-exchange bath, and (b) immediate immersion of the hot substrate into the ion-exchange bath. X-ray diffraction (XRD) analysis of the ZnO films revealed hexagonal wurtzite structure with preferential orientation along c-axis, while the scanning electron microscopy (SEM) revealed the dart-like and spherical shaped ZnO seed particles. ZnO nanostructures grown by CBD over the dart-like and spherical shaped ZnO seed particles resulted in the hierarchical and aligned ZnO nanospines/nanorods respectively. Room temperature photoluminescence (PL) study exhibited highly intense UV emission with weak visible emissions in the visible region. The growth mechanism and the role of seed layer morphology on the formation of ZnO nanostructures were discussed.

  5. Growth of novel ZnO nanostructures by soft chemical routes

    Energy Technology Data Exchange (ETDEWEB)

    Saravana Kumar, R. [PG and Research, Department of Physics, Kongunadu Arts and Science College (Autonomous), Coimbatore 641 029, Tamil Nadu (India); Sathyamoorthy, R., E-mail: rsathya59@gmail.co [PG and Research, Department of Physics, Kongunadu Arts and Science College (Autonomous), Coimbatore 641 029, Tamil Nadu (India); Matheswaran, P. [PG and Research, Department of Physics, Kongunadu Arts and Science College (Autonomous), Coimbatore 641 029, Tamil Nadu (India); Sudhagar, P.; Kang, Yong Soo [Energy Materials Laboratory, WCU Program Department of Energy Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2010-09-10

    Research highlights: Fabrication of diverse ZnO nanostructures through soft chemical routes is both fundamentally interesting and technologically important. Accordingly, in the present work novel ZnO nanostructures namely nanorods/nanospines were grown on glass substrate by integrating SILAR and CBD techniques. This simple approach not only would lead to the development of an effective and commercial growth process for diverse ZnO nanostructures, but also lead to the large-scale preparation of other nanomaterials for many important applications in nanotechnology. - Abstract: We explore a facile route to prepare one-dimensional (1D) ZnO nanostructures including nanorods/nanospines on glass substrates by integrating inexpensive successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) methods. The effect of seed layer on the growth and morphology of the ZnO nanostructures was investigated. Accordingly, the surface modification of the seed layer prepared by SILAR was carried out by employing two different drying processes namely (a) allowing the hot substrate to cool for certain period of time before immersing in the ion-exchange bath, and (b) immediate immersion of the hot substrate into the ion-exchange bath. X-ray diffraction (XRD) analysis of the ZnO films revealed hexagonal wurtzite structure with preferential orientation along c-axis, while the scanning electron microscopy (SEM) revealed the dart-like and spherical shaped ZnO seed particles. ZnO nanostructures grown by CBD over the dart-like and spherical shaped ZnO seed particles resulted in the hierarchical and aligned ZnO nanospines/nanorods respectively. Room temperature photoluminescence (PL) study exhibited highly intense UV emission with weak visible emissions in the visible region. The growth mechanism and the role of seed layer morphology on the formation of ZnO nanostructures were discussed.

  6. Excimer laser processing of ZnO thin films prepared by the sol-gel process

    International Nuclear Information System (INIS)

    Winfield, R.J.; Koh, L.H.K.; O'Brien, Shane; Crean, Gabriel M.

    2007-01-01

    ZnO thin films were prepared on soda-lime glass from a single spin-coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C 2 H 3 O 2 ) 2 ], monoethanolamine [H 2 NC 2 H 4 OH] and isopropanol. The deposited films were dried at 50 and 300 deg. C. X-ray analysis showed that the films were amorphous. Laser annealing was performed using an excimer laser. The laser pulse repetition rate was 25 Hz with a pulse energy of 5.9 mJ, giving a fluence of 225 mJ cm -2 on the ZnO film. Typically, five laser pulses per unit area of the film were used. After laser processing, the hexagonal wurtzite phase of zinc oxide was observed from X-ray diffraction pattern analysis. The thin films had a transparency of greater than 70% in the visible region. The optical band-gap energy was 3.454 eV. Scanning electron microscopy and profilometry analysis highlighted the change in morphology that occurred as a result of laser processing. This comparative study shows that our sol-gel processing route differs significantly from ZnO sol-gel films prepared by conventional furnace annealing which requires temperatures above 450 deg. C for the formation of crystalline ZnO

  7. (0 0 2-oriented growth and morphologies of ZnO thin films prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    Guo Dongyun

    2016-09-01

    Full Text Available Zinc acetate was used as a starting material to prepare Zn-solutions from solvents and ligands with different boiling temperature. The ZnO thin films were prepared on Si(1 0 0 substrates by spin-coating method. The effect of baking temperature and boiling temperature of the solvents and ligands on their morphologies and orientation was investigated. The solvents and ligands with high boiling temperature were favorable for relaxation of mechanical stress to form the smooth ZnO thin films. As the solvents and ligands with low boiling temperature were used to prepare Zn-solutions, the prepared ZnO thin films showed (0 0 2 preferred orientation. As n-propanol, 2-methoxyethanol, 2-(methylaminoethanol and monoethanolamine were used to prepare Zn-solutions, highly (0 0 2-oriented ZnO thin films were formed by adjusting the baking temperature.

  8. Fast light-induced reversible wettability of a zinc oxide nanorod array coated with a thin gold layer

    Science.gov (United States)

    Wei, Yuefan; Du, Hejun; Kong, Junhua; Tran, Van-Thai; Koh, Jia Kai; Zhao, Chenyang; He, Chaobin

    2017-11-01

    Zinc oxide (ZnO) has gained much attention recently due to its excellent physical and chemical properties, and has been extensively studied in energy harvesting applications such as photovoltaic and piezoelectric devices. In recent years, its reversible wettability has also attracted increasing interest. The wettability of ZnO nanostructures with various morphologies has been studied. However, to the best of our knowledge, there is still a lack of investigations on further modifications on ZnO to provide more benefits than pristine ZnO. Comprehensive studies on the reversible wettability are still needed. In this study, a ZnO nanorod array was prepared via a hydrothermal process and subsequently coated with thin gold layers with varied thickness. The morphologies and structures, optical properties and wettability were investigated. It is revealed that the ZnO-Au system possesses recoverable wettability upon switching between visible-ultraviolet light and a dark environment, which is verified by the contact angle change. The introduction of the thin gold layer to the ZnO nanorod array effectively increases the recovery rate of the wettability. The improvements are attributed to the hierarchical structures, which are formed by depositing thin gold layers onto the ZnO nanorod array, the visible light sensitivity due to the plasmonic effect of the deposited gold, as well as the fast charge-induced surface status change upon light illumination or dark storage. The improvement is beneficial to applications in environmental purification, energy harvesting, micro-lenses, and smart devices.

  9. Hierarchical ZnO particles grafting by fluorocarbon polymer derivative: Preparation and superhydrophobic behavior

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Dahai; Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn

    2015-07-15

    Graphical abstract: - Highlights: • The hierarchical particles were prepared by a simple, mild hydrothermal process. • The obtained “chestnut” ZnO particles show dual-scale morphology with high roughness. • FEVE derivative was creatively imported to graft onto hierarchical particles. • Superhydrophobic surfaces were obtained, on which the contact angles surpass 150°. • A special model was proposed to explain the wetting state in this work. - Abstract: Superhydrophobic surfaces on the basis of hierarchical ZnO particles grafted by fluoroethylene-vinylether (FEVE) polymer derivative were prepared using a facile, mild and low-cost method. X-ray diffraction (XRD) and scanning electron microscope (SEM) revealed that the resulting ZnO particles via hydrothermal process exhibit micro–nano dual-scale morphology with high purity under a suitable surfactant amount and alkali concentration. The grafting of FEVE derivative was confirmed by Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectrometer (EDS), suggesting that hierarchical surface of ZnO particles was an imported monomolecular layer of fluorocarbon polymer. The obtained surface fabricated by drop-casting shows considerably high contact angle and good resistance to water immersion. The wetting behavior in this work was furthermore analyzed by theoretical wetting model. This work demonstrates that the sufficient low-wettable surface and high roughness both take a vital role in the superhydrophobic behavior.

  10. Properties and characterization of bionanocomposite films prepared with various biopolymers and ZnO nanoparticles.

    Science.gov (United States)

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-06-15

    This study was aimed to develop biopolymer based antimicrobial films for active food packaging and to reduce environmental pollution caused by accumulation of synthetic packaging. The ZnO NPs were incorporated as antimicrobials into different biopolymers such as agar, carrageenan and CMC. Solvent casting method was performed to prepare active nanocomposite films. Methods such as FE-SEM, FT-IR and XRD were used to characterize resulting films. Physical, mechanical, thermal and antimicrobial properties were also examined. Remarkable surface morphological differences were observed between control and nanocomposite films. The crystallinity of ZnO was confirmed by XRD analysis. The addition of ZnO NPs increased color, UV barrier, moisture content, hydrophobicity, elongation and thermal stability of the films, while decreased WVP, tensile strength and elastic modulus. ZnO NPs impregnated films inhibited growth of L. monocytogenes and E. coli. So these newly prepared nanocomposite films can be used as active packaging film to extend shelf-life of food. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Properties of Semiconductors: Synthesis of Oriented ZnO for Photoelectrochemistry and Photoremediation

    Science.gov (United States)

    Koenig, Emma; Jacobs, Ari; Lisensky, George

    2017-01-01

    Semiconductors are an important class of materials; preparing ZnO nanorods allows semiconducting properties to be easily observed. The week before lab, groups of four students take 15 min to setup two fluorine-doped tin oxide glass (FTO) slides in a zinc nitrate and hexamethylenetetramine solution stored at 90°C until the next lab. Hexagonal ZnO…

  12. Photovoltaic properties of undoped ZnO thin films prepared by the spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Ikhmayies, S.J. [Applied Science Private Univ., Amman (Jordan). Dept. of Physics; Abu El-Haija, N.M.; Ahmad-Bitar, R.N. [Jordan Univ., Amman (Jordan). Dept. of Physics

    2009-07-01

    Zinc oxide (ZnO) can be used as a window material, transparent electrode and active layer in different types of solar cells, UV emitters, and UV sensors. In addition to being low cost, ZnO is more abundant than indium tin oxide. ZnO is non toxic and has a high chemical stability in reduction environments. When ZnO films are made without any intentional doping, they exhibit n-type conductivity. ZnO thin films can be prepared by reactive sputtering, laser ablation, chemical-vapour deposition, laser molecular-beam epitaxy, thermal evaporation, sol-gel, atomic layer deposition and spray pyrolysis, with the latter being simple, inexpensive and adaptable to large area depositions. In this work ZnCl{sub 2} was used as a source of Zn where it was dissolved in distilled water. The structural, electrical and optical properties of the films were investigated due to their important characteristic for solar cell applications. Polycrystalline ZnO thin films were deposited on glass substrate by spray pyrolysis using a home-made spraying system at substrate temperature of 450 degrees C. The films were characterized by recording and analyzing their I-V plots, their transmittance, X-ray diffraction and SEM micrographs. There resistivity was found to be about 200 ohms per cm and their bandgap energy about 3.27 eV. X-ray diffraction patterns revealed that the films have a hexagonal wurtzite structure and are highly ordered with a preferential orientation (002). SEM images revealed that the substrates are continuously covered and the surface of the film is uniform. 16 refs., 4 figs.

  13. Characterization of LPD-TiO2 compact layer in ZnO nano-rods photoelectrode for dye-sensitized solar cell

    Science.gov (United States)

    Huang, Jung-Jie; Wu, Chih-Kan; Hsu, Chun-Fa

    2017-12-01

    A titanium oxide (TiO2) compact layer was used to enhance the performance of a dye-sensitized solar cell (DSSC) by reducing the electrical loss from recombination at the indium tin oxide (ITO)/electrolyte interface and by improving the electrical contact between ITO and the zinc oxide (ZnO) nano-rod photoelectrode. The TiO2 compact layer was deposited on ITO glass using the liquid phase deposition (LPD) method. DSSCs fabricated with and without the LPD-TiO2 compact layer were compared. In addition, various thicknesses of the LPD-TiO2 compact layer were evaluated. The light-to-electricity conversion efficiency of the DSSC increased from 0.43 to 0.75% by incorporating the LPD-TiO2 compact layer. Experimental results demonstrated that the LPD method is a promising alternative to the conventional TiO2 compact layer technology for the production of high-performance DSSCs.

  14. Enhanced local piezoelectric response in the erbium-doped ZnO nanostructures prepared by wet chemical synthesis

    Directory of Open Access Journals (Sweden)

    Reza Zamiri

    2017-03-01

    Full Text Available Pure and erbium (Er doped ZnO nanostructures were prepared by simple and cost effective wet chemical precipitation method. The successful doping with phase purity of prepared ZnO nanostructure was confirmed by X-ray diffraction (XRD and their Rietveld analysis. The change in structural morphology of nanoscale features of prepared ZnO nanopowders on Er doping was observed from their scanning electron microscopy (SEM images. The presence of Er in prepared ZnO nanopowder was further confirmed from corresponding energy dispersive X-ray spectroscopy (EDX spectra of scanned SEM images. Piezoelectric properties of before (green samples and after sintering of consolidated compact of synthesized nanopowders were successfully measured. The out-of-plane (effective longitudinal and in-plane (effective shear coefficients of the samples were estimated from the local piezoresponse.

  15. Electrochemical characterization of silver nanorod electrodes prepared by oblique angle deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tang, X-J [Department of Physics and Astronomy, Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 (United States); Zhang, G [Department of Biological and Agriculture Engineering, Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 (United States); Zhao, Y-P [Department of Physics and Astronomy, Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602 (United States)

    2006-09-14

    Ag nanorod electrodes with different nanorod lengths are fabricated by a simple vacuum deposition technique, oblique angle deposition (OAD). The as-grown Ag nanorods are aligned on the substrate and have a diameter of {approx}60-70 nm, a density of {approx}200-300 x 10{sup 7} cm{sup -2}, and a tilting angle of {approx}70 deg. -80 deg. with respect to the surface normal. The electrochemical behaviours of the Ag nanorod electrode are characterized by cyclic voltammetry at various scan rates with comparison to an Ag thin-film electrode. The capacitive current is found to be proportional to the actual surface area, and the faradic redox current also increases monotonically with the surface area of the nanorod electrodes, but the increase is not as significant as that of the capacitive current due to the diffusion layer overlapping for the highly compacted nanorods. This indicates that the Ag nanorod electrode could improve the electrolytic sensor for amperometric response measurements, especially for the bimolecular measurements due to the biocompatibility of Ag. The high capacitance also suggests a promising usage of the developed nanostructures for battery and energy storage applications.

  16. Applying RF Magnetron sputtering to prepare ZnO thin films and their characterization

    International Nuclear Information System (INIS)

    Saad, M.; Kassis, A.

    2009-05-01

    ZnO thin films were prepared using Rf magnetron sputtering under several preparation conditions (different values of deposition pressure, Rf power, substrate temperature). The optical properties of these films were investigated by measuring their transmission in the spectral range (300-1000 nm), and the electrical properties were investigated by measuring their electrical resistance. Results have been discussed in terms of the modified Thornton model for sputtered thin metal oxide films. Preparation conditions for depositing the highly resistive transparent i-ZnO buffer layer and the highly conducting transparent n-ZnO window layer for solar cells were proposed. (author)

  17. Synthesis and Photocatalytic Performance of RGO/ZnO Nanorod Composites

    Directory of Open Access Journals (Sweden)

    LU Jia

    2016-12-01

    Full Text Available ZnO nanorods and RGO/ZnO nanorods composites were prepared by hydrothermal method. The influence of RGO content on the photocatalytic activity of RGO/ZnO nanorods composites was studied. ZnO nanorods and RGO/ZnO nanocomposites were characterized by X-ray diffraction (XRD, field emission electron microscopy (FESEM, X-ray photoelectron spectroscopy (XPS and diffuse reflectance UV-visible absorption spectroscopy techniques. The results show that RGO/ZnO samples are synthesized successfully. With different additions of GO, the RGO/ZnO samples obtained exhibit different absorption characteristics in visible light region. The photocatalytic results of using methyl orange (MO as the simulated pollutant show that RGO/ZnO nanorods composites exhibit high degradation efficiency under UV-Vis light illumination. The highest photocatalytic performance is obtained for RGO/ZnO composites when the mass ratio of RGO to ZnO is 3%. MO is almost completely degraded in 120min. RGO/ZnO also shows the visible-light-driven photocatalytic activity under visible light illumination (λ>400nm, and the maximum MO degradation efficiency in 180min can reach 26.2%, meanwhile, RGO/ZnO samples exhibit good photostability.

  18. Comparative study of ZnO thin films prepared by different sol-gel route

    Directory of Open Access Journals (Sweden)

    F Esmaieli Ghodsi

    2012-03-01

    Full Text Available   Retraction Notice    The paper "Comparative study of ZnO thin films prepared by different sol-gel route" by H. Absalan and F. E. Ghodsi, which appeared in Iranian Journal of Physics Research, Vol. 11, No. 4, 423-428 (in Farsi is translation of the paper "Comparative Study of ZnO Thin Films Prepared by Different Sol-Gel Route" by F. E. Ghodsi and H. Absalan, which appeared in ACTA PHYSICA POLONICA A, Vol 118 (2010 (in English and for this reason is retracted from this journal.The corresponding author  (and also the first author is the only responsible person for this action.   

  19. Nanostructured ZnO thin films prepared by sol–gel spin-coating

    Energy Technology Data Exchange (ETDEWEB)

    Heredia, E., E-mail: heredia.edu@gmail.com [UNIDEF (CONICET-MINDEF), J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Bojorge, C.; Casanova, J.; Cánepa, H. [UNIDEF (CONICET-MINDEF), J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Craievich, A. [Instituto de Física, Universidade de São Paulo, Cidade Universitária, 66318 São Paulo, SP (Brazil); Kellermann, G. [Universidade Federal do Paraná, 19044 Paraná (Brazil)

    2014-10-30

    Highlights: • ZnO films synthesized by sol–gel were deposited by spin-coating on flat substrates. • Structural features of ZnO films with several thicknesses were characterized by means of different techniques. • The thicknesses of different ZnO thin films were determined by means of FESEM and AFM. • The nanoporous structures of ZnO thin films were characterized by GISAXS using IsGISAXS software. • The average densities of ZnO thin films were derived from (i) the critical angle in 1D XR patterns, (ii) the angle of Yoneda peak in 2D GISAXS images, (iii) minimization of chi2 using IsGISAXS best fitting procedure. - Abstract: ZnO thin films deposited on silica flat plates were prepared by spin-coating and studied by applying several techniques for structural characterization. The films were prepared by depositing different numbers of layers, each deposition being followed by a thermal treatment at 200 °C to dry and consolidate the successive layers. After depositing all layers, a final thermal treatment at 450 °C during 3 h was also applied in order to eliminate organic components and to promote the crystallization of the thin films. The total thickness of the multilayered films – ranging from 40 nm up to 150 nm – was determined by AFM and FESEM. The analysis by GIXD showed that the thin films are composed of ZnO crystallites with an average diameter of 25 nm circa. XR results demonstrated that the thin films also exhibit a large volume fraction of nanoporosity, typically 30–40 vol.% in thin films having thicknesses larger than ∼70 nm. GISAXS measurements showed that the experimental scattering intensity is well described by a structural model composed of nanopores with shape of oblate spheroids, height/diameter aspect ratio within the 0.8–0.9 range and average diameter along the sample surface plane in the 5–7 nm range.

  20. Detailed investigations of ZnO photoelectrodes preparation for dye sensitized solar cells.

    Science.gov (United States)

    Marczak, Renata; Werner, Fabian; Ahmad, Rameez; Lobaz, Volodymyr; Guldi, Dirk M; Peukert, Wolfgang

    2011-04-05

    Wurtzite ZnO hexagonal nanopyramids were successfully synthesized in the liquid phase from homogeneous methanolic solutions of zinc acetate and tetramethylammonium hydroxide at an excess of zinc ions. The formation and properties of the nanocrystals were examined as a function of synthesis conditions. No significant influence of the [Zn(2+)]/[OH(-)] ratio was noticed on the final particle size, in spite of increased amounts of OH(-) ions, which tend to accelerate the particle nucleation and growth. Nevertheless, the reactant concentration ratio influences the surface properties of the ZnO nanocrystals. Mesoporous ZnO films were prepared by doctor blading ethanolic pastes containing ZnO nanoparticles and ethyl cellulose onto FTO conductive glass substrate followed by calcination. Additionally, the influence of a plasticizer (triacetin)-used during the paste preparation-on the film quality was investigated. A higher content of ZnO nanoparticles and plasticizer in the pastes improved the film quality. Four different temperatures (i.e., 400, 425, 450, and 475 °C) were used for the film calcination and their influence on the structural properties of the films was characterized. In principle, increasing the calcination temperature goes hand in hand with an increase of particle size, as well as the pore diameter and reduction of the surface area. Suitable mesoporous films were employed as photoanodes in dye sensitized solar cells (DSSCs). In order to assess the effect of the varied parameters on complete DSSC devices-using cis-diisothiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium(II)bis(tetrabutylammonium (N719) as a sensitizer-incident photon to current efficiency (IPCE) and current voltage measurements were carried out. The IPCE measurements confirmed photoinduced electron injection from the dye, reaching IPCE values up to 76%. Furthermore, current-voltage characteristics of complete cells emphasized the importance of the proper preparation methods and

  1. Electroluminescence dependence on the organic thickness in ZnO nano rods/Alq3 heterostructure devices.

    Science.gov (United States)

    Kan, Pengzhi; Wang, Yongsheng; Zhao, Suling; Xu, Zheng; Wang, Dawei

    2011-04-01

    ZnO nanorods are synthesised by a hydrothermal method on ITO glass. Their crystallization and morphology are detected by XRD and SEM, respectively. The results show that the ZnO nanorod array has grown primarily along a direction aligned perpendicular to the ITO substrate. The average height and diameter of the nanorods is about 130 nm and 30 nm, respectively. Then ZnO nano rods/Alq3 heterostructure LEDs are prepared by thermal evaporation of Alq3 molecules. The thicknesses of the Alq3 layers are 130 nm, 150 nm, 170 nm and 190 nm, respectively. The electroluminescence of the devices is detected under different DC bias voltages. The exciton emission of Alq3 is detected in all devices. When the thickness of Alq3 is 130 nm, the UV electroluminescence of ZnO is around 382 nm, and defect emissions around 670 nm and 740 nm are detected. Defect emissions of ZnO nanorods are prominent. When the thickness of Alq3 increases to over 170 nm, it is difficult to observe defect emissions from the ZnO nano rods. In such devices, the exciton emission of Alq3 is more prominent than other emissions under different bias voltage.

  2. ZnO THIN FILMS PREPARED BY SPRAY-PYROLYSIS TECHNIQUE FROM ORGANO-METALLIC PRECURSOR

    Directory of Open Access Journals (Sweden)

    Martin Mikulics

    2012-07-01

    Full Text Available Presented experiments utilize methanolic solution of zinc acetyl-acetonate as a precursor and sapphire (001 as a substrate for deposition of thin films of ZnO. The X-ray diffraction analysis revealed polycrystalline character of prepared films with preferential growth orientation along c-axis. The roughness of prepared films was assessed by AFM microscopy and represented by roughness root mean square (RMS value in range of 1.8 - 433 nm. The surface morphology was mapped by scanning electron microscopy showing periodical structure with several local defects. The optical transmittance spectrum of ZnO films was measured in wavelength range of 200-1000 nm. Prepared films are transparent in visible range with sharp ultra-violet cut-off at approximately 370 nm. Raman spectroscopy confirmed wurtzite structure and the presence of compressive stress within its structure as well as the occurrence of oxygen vacancies. The four-point Van der Pauw method was used to study the transport prosperities. The resistivity of presented ZnO films was found 8 × 10–2 Ω cm with carrier density of 1.3 × 1018 cm–3 and electron mobility of 40 cm2 V–1 s–1.

  3. Synthesis, characterization and charge transport mechanism of CdZnO nanorods

    International Nuclear Information System (INIS)

    Mahmoud, Waleed E.; Al-Ghamdi, A.A.; El-Tantawy, F.; Al-Heniti, S.

    2009-01-01

    ZnO and Cd-doped ZnO nanostructures were prepared by new facile method at 80 deg. C. XRD measurement indicated that both samples had typical hexagonal wurtzite structures. Transmission electron microscopy (TEM) measurement shows that rod-like crystals have been formed. EDX measurement confirms the incorporation of the cadmium ion into the crystalline lattice of ZnO and indicated that cadmium ions uniformly distributed on the surface of the rods. The doping with cadmium ions has a great influence on the optical properties of the ZnO. The electrical measurements of Cd-doped ZnO nanorod were measured. The current-voltage (I-V) characteristic curve revealed that the charge transport above 4 V is mainly non-linear due to grain boundary contribution. The complex impedance spectroscopy was confirmed that the grain boundary effect controls the charge transport mechanism through CdZnO ceramic material.

  4. Influence of Zr doping on structure and morphology of TiO2 nanorods prepared using hydrothermal method

    Science.gov (United States)

    Muslimin, Masliana; Jumali, Mohammad Hafizuddin; Tee, Tan Sin; Beng, Lee Hock; Hui, Tan Chun; Chin, Yap Chi

    2018-04-01

    The aim of this work is to investigate the effect of Zr doping on TiO2 nanostructure. TiO2 nanorods thin films with different Zr-doping concentrations (6 × 10-3 M, 13 × 10-3 M and 25 × 10-3 M) were successfully prepared using a simple hydrothermal method. The structural and morphological properties of the samples were evaluated using XRD and FESEM respectively. The XRD results revealed that the TiO2 in all samples stabilized as rutile phase. The FESEM micrographs confirmed that TiO2 exist as square like nanorods with blunt tips. Although the crystallographic nature remains unchanged, the introduction of Zr has altered the surface density, structure and morphology of TiO2 which subsequently will have significant effect on its properties.

  5. Preparation and surface modification of hierarchical nanosheets-based ZnO microstructures for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Yongming; Lin, Yu, E-mail: linyuyrr@163.com; Lin, Yibing; Yang, Jiyuan

    2014-02-15

    This paper reports a simple one-step hydrothermal route for the preparation of hierarchical nanosheets-based ZnO microstructures and their application to dye-sensitized solar cells. The morphologies of the products were controlled by the dosage of the reactants. Their physical characteristics were detected by X-ray diffraction, a field-emission scanning electron microscope and a surface analyzer. It is proved that the sample of ZnO microspheres with larger surface area and stronger light-trapping capacity since the superiority of their entirely spherical structures exhibits better photoelectrochemical properties than the mixtures of ZnO microspheres and ZnO microflowers. A dye-sensitized solar cell assembled by the ZnO microspheres as photoanode shows an energy conversion efficiency of 2.94% after surface modification by tetrabutyl titanate solution at 90 {sup °}C. This result is over 1.6 times higher than the non-modified cell fabricated by the ZnO microspheres on the basis of the external improvement and the stability enhancement for the dye-sensitized ZnO photoanode. - Graphical abstract: Influences on energy conversion efficiency of the dye-sensitized solar cells assembled by decorating hierarchical nanosheets-based ZnO microstructures with tetrabutyl titanate solution at different temperatures. Display Omitted - Highlights: • Hierarchical nanosheets-based ZnO microstructures were controllably synthesized. • The ZnO microspheres show good optical and electrochemical properties. • The ZnO microspheres were modified by C{sub 16}H{sub 36}O{sub 4}Ti solution. • Remarkable increase of conversion efficiency is observed after surface modification.

  6. The role of annealing temperature variation on ZnO nanorods array deposited on TiO2 seed layer

    Science.gov (United States)

    Asib, N. A. M.; Aadila, A.; Afaah, A. N.; Rusop, M.; Khusaimi, Z.

    2018-05-01

    Seed layer of Titanium dioxide (TiO2) by sol-gel spin coating technique were coated on glass substrate to grow Zinc oxide nanorods (ZNR) by solution-immersion method. The fabricated ZNR were annealed at various temperatures ranged from 400 to 600° C. FESEM images revealed that smaller ZNR were densely grown at optimum temperature of 450 and 500°C. Meanwhile, for all samples a dominant (0 0 2) diffraction peak of ZNR recorded by XRD patterns was at 34.4° which corresponding to hexagonal ZNR with a wurtzite structure. UV-Vis absorbance spectra showed the maximum absorption properties at UV region were detected at 450 and 500°C. The samples also showed high absorbance values at visible region.

  7. Zinc oxide nanorod clusters deposited seaweed cellulose sheet for antimicrobial activity.

    Science.gov (United States)

    Bhutiya, Priyank L; Mahajan, Mayur S; Abdul Rasheed, M; Pandey, Manoj; Zaheer Hasan, S; Misra, Nirendra

    2018-06-01

    Seaweed cellulose was isolated from green seaweed Ulva fasciata using a common bleaching agent. Sheet containing porous mesh was prepared from the extracted seaweed crystalline cellulose along with zinc oxide (ZnO) nanorod clusters grown over the sheet by single step hydrothermal method. Seaweed cellulose and zinc oxide nanorod clusters deposited seaweed cellulose sheet was characterized by FT-IR, XRD, TGA, and SEM-EDX. Morphology showed that the diameter of zinc oxide nanorods were around 70nm. Zinc oxide nanorod clusters deposited on seaweed cellulose sheet gave remarkable antibacterial activity towards gram-positive (Staphylococcus aureus, Bacillus ceresus, Streptococcus thermophilis) and gram-negative (Escherichia coli, Pseudomonas aeruginous) microbes. Such deposited sheet has potential applications in pharmaceutical, biomedical, food packaging, water treatment and biotechnological industries. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Methodology for sample preparation and size measurement of commercial ZnO nanoparticles

    Directory of Open Access Journals (Sweden)

    Pei-Jia Lu

    2018-04-01

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

  9. Aggregation and growth of ZnO quantum dots prepared from sol-gel chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Santilli, C.V.; Pulcinelli, S.H.; Caetano, B.L. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil); Briois, V.B [Synchrotron SOLEIL, Saint-Aubin (France)

    2016-07-01

    Full text: Herein we discuss in depth the mechanisms of growth control of ZnO quantum dots (Q-dot) prepared from the zinc oxy-acetate ethanolic solution by the addition of LiOH. Through in situ monitoring of Q-dot radii and of aggregation index calculated from UV-Vis absorption spectra and small-angle X-ray scattering (SAXS) the aggregation and growth of ZnO nanocrystal was well described from two kinetic models: during the first step (t< 50 min) the structural evolution is controlled by the coalescence caused by the oriented attachment between the nanocrystal aggregates while at the advanced time (t> 50 min) the Q-dot coarsening follows the Ostwald ripening (OR) mechanism. From the higher oriented attachment efficiency observed here as compared with early reported synthesis using NaOH and KOH, we propose an universal mechanism to control coalescence and coarsening of ZnO nanocrystal provided from the shield caused by the adsorption of the alkali cation. From X-ray diffraction and transmission electron microscopy results we demonstrate that this mechanism is also useful to prepare Q-dot powders with controlled size. (author)

  10. Work-Function and Surface Energy Tunable Cyanoacrylic Acid Small-Molecule Derivative Interlayer on Planar ZnO Nanorods for Improved Organic Photovoltaic Performance.

    Science.gov (United States)

    Ambade, Swapnil B; Ambade, Rohan B; Bagde, Sushil S; Lee, Soo-Hyoung

    2016-12-28

    The issue of work-function and surface energy is fundamental to "decode" the critical inorganic/organic interface in hybrid organic photovoltaics, which influences important photovoltaic events like exciton dissociation, charge transfer, photocurrent (J sc ), open-circuit voltage (V oc ), etc. We demonstrate that by incorporating an interlayer of cyanoacrylic acid small molecular layer (SML) on solution-processed, spin-coated, planar ZnO nanorods (P-ZnO NRs), higher photovoltaic (PV) performances were achieved in both inverted organic photovoltaic (iOPV) and hybrid organic photovoltaic (HOPV) devices, where ZnO acts as an "electron-transporting layer" and as an "electron acceptor", respectively. For the tuned range of surface energy from 52.5 to 33 mN/m, the power conversion efficiency (PCE) in bulk heterojunction (BHJ) iOPVs based on poly(3-hexylthiophene) (P3HT) and phenyl-C 60 -butyric acid methyl ester (PC 60 BM) increases from 3.16% to 3.68%, and that based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene)-2-carboxylate-2-6-diyl)] (PTB7:Th):[6,6]-phenyl C 71 butyric acid methyl ester (PC 71 BM) photoactive BHJ increases from 6.55% to 8.0%, respectively. The improved PV performance in iOPV devices is majorly attributed to enhanced photocurrents achieved as a result of reduced surface energy and greater electron affinity from the covalent attachment of the strong electron-withdrawing cyano moiety, while that in HOPV devices, where PCE increases from 0.21% to 0.79% for SML-modified devices, is ascribed to a large increase in V oc benefitted due to reduced work function effected from the presence of strong dipole moment in SML that points away from P-ZnO NRs.

  11. Synthesis and characterization of ZnO nanostructures on noble-metal coated substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dikovska, A.Og. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Sofia 1784 (Bulgaria); Atanasova, G.B. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 11, 1113 Sofia (Bulgaria); Avdeev, G.V. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 11, 1113 Sofia (Bulgaria); Nedyalkov, N.N. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Sofia 1784 (Bulgaria)

    2016-06-30

    Highlights: • ZnO nanostructures were fabricated on Au–Ag alloy coated silicon substrates by applying pulsed laser deposition. • Morphology of the ZnO nanostructures was related to the Au–Ag alloy content in the catalyst layer. • Increasing the Ag content in Au–Ag catalyst layer changes the morphology of the ZnO nanostructures from nanorods to nanobelts. - Abstract: In this work, ZnO nanostructures were fabricated on noble-metal (Au, Ag and Au–Ag alloys) coated silicon substrates by applying pulsed laser deposition. The samples were prepared at a substrate temperature of 550 °C, an oxygen pressure of 5 Pa, and a laser fluence of 2 J cm{sup −2} – process parameters usually used for deposition of smooth and dense thin films. The metal layer's role is substantial for the preparation of nanostructures. Heating of the substrate changed the morphology of the metal layer and, subsequently, nanoparticles were formed. The use of different metal particles resulted in different morphologies and properties of the ZnO nanostructures synthesized. The morphology of the ZnO nanostructures was related to the Au–Ag alloy's content of the catalyst layer. It was found that the morphology of the ZnO nanostructures evolved from nanorods to nanobelts as the ratio of Au/Ag in the alloy catalyst was varied. The use of a small quantity of Ag in the Au–Ag catalyst (Au{sub 3}Ag) layer resulted predominantly in the deposition of ZnO nanorods. A higher Ag content in the catalyst alloy (AuAg{sub 2}) layer resulted in the growth of a dense structure of ZnO nanobelts.

  12. ZnO and copper indium chalcogenide heterojunctions prepared by inexpensive methods

    International Nuclear Information System (INIS)

    Berruet, M.; Di Iorio, Y.; Troviano, M.; Vázquez, M.

    2014-01-01

    Solution-based techniques were used to prepare ZnO/CuIn(Se, S) 2 heterojunctions that serve as solar cell prototypes. A duplex layer of ZnO (compact + porous) was electrodeposited. Chalcogenide thin films were deposited using successive ionic layer adsorption and reaction method (SILAR). By subsequent thermal treatments in two different atmospheres, CuInSe 2 (CISe) and CuInSe 2−x S x (CISeS) were obtained. The composition and morphology of the annealed films were characterized by GXRD, micro-Raman spectroscopy and SEM. Devices prepared with CISe and CISeS show a clear photo-response. The introduction of a buffer layer of TiO 2 into the ZnO/chalcogenide interface was necessary to detect photocurrent. The presence of CISeS improves the response of the cell, with higher values of short circuit current density, open circuit potential and fill factor. These promising results show that it is possible to prepare photovoltaic heterojunctions by depositing chalcogenides onto porous ZnO substrates using low-cost solution-based techniques. - Highlights: • Heterojunctions that serve as solar cell prototypes were prepared using solution-based techniques. • The devices comprised a double layer of ZnO and CuInSe 2 or CuInSe 0.4 S 1.6 . • A TiO 2 buffer layer in the ZnO/chalcogenide interface is necessary to detect photocurrent. • The incorporation of S improved the response of the photovoltaic heterojunction

  13. ZnO and copper indium chalcogenide heterojunctions prepared by inexpensive methods

    Energy Technology Data Exchange (ETDEWEB)

    Berruet, M., E-mail: berruetm@gmail.com [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Di Iorio, Y. [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Troviano, M. [Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas (PROBIEN, CONICET-UNCo), Buenos Aires 1400, Q8300IBX Neuquén (Argentina); Vázquez, M. [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina)

    2014-12-15

    Solution-based techniques were used to prepare ZnO/CuIn(Se, S){sub 2} heterojunctions that serve as solar cell prototypes. A duplex layer of ZnO (compact + porous) was electrodeposited. Chalcogenide thin films were deposited using successive ionic layer adsorption and reaction method (SILAR). By subsequent thermal treatments in two different atmospheres, CuInSe{sub 2} (CISe) and CuInSe{sub 2−x}S{sub x} (CISeS) were obtained. The composition and morphology of the annealed films were characterized by GXRD, micro-Raman spectroscopy and SEM. Devices prepared with CISe and CISeS show a clear photo-response. The introduction of a buffer layer of TiO{sub 2} into the ZnO/chalcogenide interface was necessary to detect photocurrent. The presence of CISeS improves the response of the cell, with higher values of short circuit current density, open circuit potential and fill factor. These promising results show that it is possible to prepare photovoltaic heterojunctions by depositing chalcogenides onto porous ZnO substrates using low-cost solution-based techniques. - Highlights: • Heterojunctions that serve as solar cell prototypes were prepared using solution-based techniques. • The devices comprised a double layer of ZnO and CuInSe{sub 2} or CuInSe{sub 0.4}S{sub 1.6}. • A TiO{sub 2} buffer layer in the ZnO/chalcogenide interface is necessary to detect photocurrent. • The incorporation of S improved the response of the photovoltaic heterojunction.

  14. Nanostructured gold microelectrodes for SERS and EIS measurements by incorporating ZnO nanorod growth with electroplating

    Science.gov (United States)

    Zong, Xianli; Zhu, Rong; Guo, Xiaoliang

    2015-01-01

    In this paper, a fine gold nanostructure synthesized on selective planar microelectrodes in micro-chip is realized by using an advanced hybrid fabrication approach incorporating growth of nanorods (NRs) with gold electroplating. By this developed nanostructure, integration of in-situ surface-enhanced Raman spectroscopy (SERS) detection with electrochemical impedance spectroscopy (EIS) measurement for label-free, nondestructive, real-time and rapid monitoring on a single cell has been achieved. Moreover, parameters of Au nanostructures such as size of nanoholes/nanogaps can be controllably adjusted in the fabrication. We have demonstrated a SERS enhancement factor of up to ~2.24 × 106 and double-layer impedance decrease ratio of 90% ~ 95% at low frequency range below 200 kHz by using nanostructured microelectrodes. SERS detection and in-situ EIS measurement of a trapped single cell by using planar microelectrodes are realized to demonstrate the compatibility, multi-functions, high-sensitivity and simplicity of the micro-chip system. This dual function platform integrating SERS and EIS is of great significance in biological, biochemical and biomedical applications. PMID:26558325

  15. Preparation, characterization, and nonlinear optical properties of hyb