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Synthesis of Single Crystalline Titanium Oxide and Sodium Titanate Nanorods via Salt-Assisted Ultrasonic Spray Pyrolysis

Hwangbo Y., Yoo J.-H., Lee Y.-I.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 2B

1411--1414

EN

The simple and continuous synthesis of single crystalline anatase titanium dioxide and sodium titanate nanorods by a saltassisted ultrasonic spray pyrolysis method is demonstrated. This method does not require expensive precursors, long reaction time, and physical templates or surfactant. In addition, its continuous nature makes it a suitable method for the large-scale preparation. Moreover, the effect of a salt concentration in a starting solution on material properties, including morphology and phase of the synthesized products was systematically investigated. The synthesized nanorods had one-dimensionality, a single crystalline and the average diameter of 12.3 nm with dual phases of titanium dioxide and sodium titanate by FE-SEM, XRD, HR-TEM as well as FFT-converted SAED pattern analysis.

2

Synthesis and characterization of CdS nanorods by combined sonochemical-solvothermal method

Bozkurt P. A., Derkuş B.

Materials Science Poland

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2016

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Vol. 34, No. 3

684--690

EN

Cadmium sulfide (CdS) nanorods with a diameter of 50 nm and length of approximately 200 nm have been synthesized using combined sonochemical-solvothermal method. Structural properties of CdS nanoparticles synthesized by this method have been compared with the CdS nanoparticles synthesized by sonochemical method alone. The synthesized CdS nanostructures have been characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) methods. In addition, the factors affecting the formation of the structures, including reaction time, different type and ratio of precursors, such as sulphur source, have been investigated. Comparison of the results obtained by both the synthesis methods revealed CdS nanoparticles synthesized by the combined sonochemical-solvothermal method to be of high morphological homogeneity compared to the sonochemical method alone. It is interesting to note that ethylenediamine has been found to be prevented from agglomeration by using the combined sonochemical-solvothermal method as the synthesis method. A modified growth mechanism under the inducement of ethylenediamine solutions for the CdS nanorods has been suggested.

3

Si/ZnO nanorods with Ag nanoparticles/AZO heterostructures in PV applications

Gwóźdź K., Płaczek-Popko E., Gumienny Z., Zielony E., Pietruszka R., Witkowski B. S., Wachnicki Ł., Gierałtowska S., Godlewski M., Chang L. B.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 3

529--533

EN

Our studies focus on test structures for photovoltaic applications based on zinc oxide nanorods grown using a low-temperature hydrothermal method on a p-type silicon substrate. The nanorods were covered with silver nanoparticles of two diameters – 20–30 nm and 50–60 nm – using a sputtering method. Scanning electron microscopy (SEM) micrographs showed that the deposited nanoparticles had the same diameters. The densities of the nanorods were obtained by means of atomic force microscope (AFM) images. SEM images and Raman spectroscopy confirmed the hexagonal wurtzite structure of the nanorods. Photoluminescence measurements proved the good quality of the samples. Afterwards an atomic layer deposition (ALD) method was used to grow ZnO:Al (AZO) layer on top of the nanorods as a transparent electrode and ohmic Au contacts were deposited onto the silicon substrate. For the solar cells prepared in that manner the current-voltage (I-V) characteristics before and after the illumination were measured and their basic performance parameters were determined. It was found that the spectral characteristics of a quantum efficiency exhibit an increase for short wavelengths and this behavior has been linked with the plasmonic effect.

4

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

Singh A., Vishwakarma H. L.

Materials Science Poland

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2015

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Vol. 33, No. 4

751--759

EN

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 mu m to 1.61 mu m and the length is about 4.89 mu m. 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.

5

Catalyst free growth of single-crystalline bismuth nanorods by closed space sublimation technique

Usman W., Maqsood A.

Materials Science Poland

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2015

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Vol. 33, No. 2

381--390

EN

In the present study, bismuth (Bi) thin films having thickness of 335 nm have been deposited onto a glass substrate by closed space sublimation (CSS) technique. Besides this, spontaneous growth of Bi nanorods has also been investigated for the first time, without template and catalyst assistance in a substrate temperature range of 380 to 430 degrees C using CSS technique. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate microstructure, morphology and roughness of the Bi nanorods. The diameter and length ranges of Bi nanorods were 80 to 400 nm and 3 to 5 mu m, respectively. Moreover, they exhibited a rhombohedral structure with a dominant peak indexed at (012), (104), and (110). The mass percentage of Bi, determined by energy dispersive X-ray (EDX), was 99.93 %. The studies of electrical resistivity, Hall coefficient, magnetoresistivity, hole mobility and carrier concentration of Bi thin films were performed at 300 to 350 K and the electrical properties were found to be a function of temperature. The basic aim was to investigate the spectacular evolution of Bi nanostructures on as-deposited thin films and effects of thickness on their structural, electrical and dielectric properties. Detailed examination of SEM micrographs eliminated all other growth modes except self-catalytic tip growth by Vapor-Solid (VS) growth process which is believed to provide the driving force for spontaneous nanorod growth at high substrate temperature. Deposition of thinner Bi films provided a new possibility for fabrication of Bi nanorods of high quality.

6

Large-Area Sodium Titanate Nanorods Formed On Titanium Surface Via NaOH Alkali Treatment

Lee K., Yoo D.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1371--1374

EN

Ti surfaces covered with large sodium titanate nanorods act as efficient electrodes for energy conversion and environmental applications. In this study, sodium titanate nanorod films were prepared on a Ti substrate in a 5M NaOH aqueous solution followed by heat treatment. The morphological characterization and the crystal structures of the sodium titanate nanorods were investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Thin amorphous sodium titanate layers formed during the alkali-treatment, and sodium titanate nanorods were obtained after heat treatment at a temperature of 700°C. The sodium titanate nanorods obtained at this temperature had a thickness of about 80 nm and a length of 1 μm. The crystal structure of the sodium titanate was identified with the use of Na2Ti5O11. The nanorods were agglomerated at a temperature above 900°C, and large-scale nanorods formed on the Ti surface, which may be used for electrodes for energy conversion applications.

7

Nanomechanical Properties of Metallic fcc Nanorods from Molecular Simulations with the Sutton-Chen Force Field

Białoskorski M., Rybicki J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2012

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Vol. 16, No 1-2

97-133

EN

Basic elastic constants (Young’s modulus, Poisson’s ratio, shear modulus) were determined for several monocrystalline, metallic (Ni, Cu, Pt, Au) nanorods using molecular dynamics with the Sutton-Chen force field. Stress-strain curves were also calculated and discussed.

8

Surfactant-assisted synthesis and characterization of hydroxyapatite nanorods under hydrothermal conditions

Salarian M., Solati-Hashjin M., Sara Shafiei S., Goudarzi A., Salarian R., Nemati A.

Materials Science Poland

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2009

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Vol. 27, No. 4/1

961--971

EN

Hydroxyapatite (HAp) nanorods with uniform morphology and controllable size were successfully synthesized by precipitating Ca(NO3)2o4H2O and (NH4)2HPO4 in the presence of cetyltrimethylammonium bromide (CTAB) and polyethylene glycol 400 (PEG 400) as cationic surfactant and non-ionic cosurfactant, respectively, under hydrothermal conditions. The effect of hydrothermal temperature on the composition, morphology and size of HAp particles was studied using X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM). Results revealed that the morphology and size of HAp particles can be effectively controlled by the presence of CTAB and PEG surfactants. In addition, the temperature of the hydrothermal treatment plays an important role in controlling the morphology and size of HAp particles. The aspect ratio of rod-like particles increases with the increase in the hydrothermal temperature. Moreover, the crystallinity of HAp powders increases with the increase in the hydrothermal temperature. The template action of CTAB and the co-template action of PEG 400 used to regulate the nucleation and crystal growth are also discussed.

9

Eco-friendly Synthesis of ZnO Nanorods in Water Using Acetylacetone as Template

Farzaneh F., Faal Hamedan N.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 8

1513--1517

EN

Nanocrystals of ZnO were prepared by microwave irradiation in water using Zn(II) acetate and acetylacetone (acac) as template. The ZnO obtained nanorods with hexagonal (wurtzite) structure were characterized by X-ray power diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV-vis absorption and FTIR spectroscopy.

10

Synthesis and characterization of SiO2 and SiC micro/nanostructures

Zhu G., Zou X. P., Cheng J., Su Y.

Archives of Metallurgy and Materials

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2008

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Vol. 53, iss. 3

727-734

EN

Silica-based nanowires, straight nanorods, straight Y-shaped słlica nanorods, flower-like microstructures, and SiC/Si02 core-shell coaxial nanocables have been generated through a simple thermal evaporation method. The synthesized samples were characterized by means ot" scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectrum. Generated silica nanowires with a diameter of about lOOnm and length of up to several tens of micrometers, straight silica nanorods and Y-shaped nanorods with a diameter about 50-200nm, and novel flower-like silica microstructures all are amorphous and consist only of silicon oxide, and have a neat smooth surface. Generated SiC/SiO? core-shell coaxial nanocables have a crystalline core and a surrounding amorphous layer. The results show that the present method should be possible to synthesis various micro/nanostructures under appropriate experimental conditions. These nanostructures may find applications as building blocks in nanomechanical or nanoelectronic devices.

PL

Nanodruty na podłożu Si02, proste (straight) nanopręty, krzemionkowe nanopręty w kształcie litery Y, mikrostruktury kwiatowe, SiC/Si02 rdzeniowo-powłokowe kable koncentryczne zostały wytworzone przy zastosowaniu prostej metody odparowania cieplnego. Poddane syntezie próbki scharakteryzowano przy pomocy skaningowej mikroskopii elektronowej, transmisyjnej mikroskopii elektonowej, wysoko rozdzielczej transmisyjnej mikroskopii elektronowej, rentgenospektroskopii z dyspresją energii widma oraz widmaRaman'a. Wytworzone krzemionkowe mikrodruty o średnicy około lOOnm oraz długości dochodzącej do kilkudziesięciu mikrometyrów, proste (straight) krzeminokowe nanopręty oraz nanopręty w kształcie litery Y o średnicy około 50-200nm jak również krzemionkowe mikrostruktury kwiatowe są wszystkie amorficzne i składają się jedynie z tlenku krzemowego wykazując uporządkowaną, gładką powierzchnię. Wytworzone SiC/SiOi rdzeniowo-powłokowe kable koncentryczne posiadają rdzeń krystaliczny oraz otaczają go warstwa amorficzną. Wyniki wykazują, że metoda o której mowa może być zastosowana do syntezy różnych mikro/nanostruktur przy zachowaniu odpowiednich reżimów eksperymentalnych. Nanostruktury, o których mowa, mogą znaleźć zastosowanie jako bloki konstrukcyjne w urządzeniach mechanicznych i nanoelektrycznych.