Nickel nanopowders were synthesized by a chemical reduction of nickel ions with hydrazine hydrate at pH &#x7e;12.5. Sonication of the solutions created a temperature of 54&#x2013;65&#xB0;C to activate the reduction reaction of nickel nanoparticles. The solution pH affected the composition of the resulting nanoparticles. Nickel hydroxide nanoparticles were formed from an alkaline solution (pH&#x7e;10) of nickel-hydrazine complexed by dropwise titration. X-ray diffraction of the powder and the analysis of the resulting Williamson-Hall plots revealed that the particle size of the powders ranged from 12 to 14&#x2009;nm. Addition of polyvinylpyrrolidone into the synthesis decreased the nickel nanoparticle size to approximately 7&#x2009;nm. Dynamic light scattering and scanning electron microscopy confirmed that the particles were in the nanometer range. The structure of the synthesized nickel and nickel hydroxide nanoparticles was identified by X-ray diffraction and Fourier transform infrared spectroscopy.

Jeerapan Tientong

Stephanie Garcia

Casey R. Thurber

Teresa D. Golden

Synthesis of Nickel and Nickel Hydroxide Nanopowders by Simplified Chemical Reduction

A highly sensitive and selective Cr(VI) sensor with  graphene-based nanocomposites film as an enhanced sensing platform is reported. The detection of chromium species is a challenging task because of the different possible oxidation states in which the element can occur. The sensing film was developed by homogenously distributing Au nanoparticles (AuNPs) onto the two-dimensional (2D) graphene nanosheet matrix by electrochemical method. Such nanostructured composite film platforms combine the advantages of AuNPs and graphene nanosheets because of the synergistic effect between them. This effect greatly facilitates the electron-transfer processes and the sensing behavior for Cr(VI) detection, leading to a remarkably improved sensitivity and selectivity. The interference from other heavy metal ions is studied in detail. Such sensing elements are very promising for practical environmental monitoring applications.

Chella Santhosh

Murugan Saranya

Rajendran Ramachandran

Sathiyanathan Felix

Venugopal Velmurugan

Andrews Nirmala Grace

Graphene/Gold Nanocomposites-Based Thin Films as an Enhanced Sensing Platform for Voltammetric Detection of Cr(VI) Ions

The mechanical response of thirteen different helical multi-walled carbon nanocoils to axial compression is reported. Each nanocoil was attached to the apex of a cantilever probe tip; its dimensions and orientation relative to the tip apex were determined with scanning electron microscopy. The atomic force microscope was employed to apply a cyclic axial load on the nanocoil. Its mechanical response was determined by simultaneous collection of the thermal resonance frequency, displacement, and oscillation amplitude of the cantilever-nanotube system in real time. Depending upon compression parameters, each coil underwent buckling, bending, and slip-stick motion. Characteristic features in the thermal resonance spectrum and in the force and oscillation amplitude curves for each of these responses to induced stress are presented. Following compression studies, the structure and morphology of each nanocoil were determined by transmission electron microscopy. The compression stiffness of each nanocoil was estimated from the resonant frequency of the cantilever at the point of contact with the substrate surface. From this value, the elastic modulus of the nanocoil was computed and correlated with the coiled carbon nanotube&#x2019;s morphology.

Jabulani R. Barber

Jeffrey S. Boyles

Aldo A. Ferri

Lawrence A. Bottomley

Empirical Correlation of the Morphology of Coiled Carbon Nanotubes with Their Response to Axial Compression

CuS nanostructures have been successfully synthesized by hydrothermal route using copper nitrate and sodium thiosulphate as copper and sulfur precursors. Investigations were done to probe the effect of cationic surfactant, namely, Cetyltrimethylammonium bromide (CTAB) on the morphology of the products. A further study has been done to know the effect of reaction time on the morphology of CuS nanostructures. The FE-SEM results showed that the CuS products synthesized in CTAB were hexagonal plates and the samples prepared without CTAB were nanoplate like morphology of sizes about 40&#x2013;80&#x2009;nm. Presence of nanoplate-like structure of size about 40&#x2013;80&#x2009;nm was observed for the sample without CTAB. The synthesized CuS nanostructures were characterized by X-ray diffraction (XRD), FE-SEM, DRS-UV-Vis spectroscopy, and FT-IR spectroscopy. A possible growth mechanism has been elucidated for the growth of CuS nanostructures.

Growth of CuS Nanostructures by Hydrothermal Route and Its Optical Properties

Very fine nanosized metal oxide, namely, iron oxide (&#x3B1;-Fe2O3) has been synthesized by precipitation method using ammonia as precipitating agent and characterized by using XRD (X-ray diffraction), TGA/DTA, surface area measurement, transmission electron microscopy (TEM), and magnetic measurements techniques. XRD studies show that iron oxide was formed as &#x3B1;-Fe2O3 instead of the commonly formed magnetite nanoparticles (Fe3O4) or a mixture of magnetite (Fe3O4) and maghemite (&#x3B3;-Fe2O3, cubic), and it has rhombohedral structure. Magnetic measurements showed that iron oxide has five unpaired electrons and is ferromagnetic in nature, Ms value being 1.7&#x2009;emu/g. The particle size of the synthesized iron oxide was determined by TEM. TEM images show that the size of particles of Fe2O3 varied from 15&#x2009;nm to 49&#x2009;nm with average crystallite size 35&#x2009;nm.

Avnish Kumar Arora

Mohan Sharma

Ritu Kumari

Vivek Sheel Jaswal

Pankaj Kumar

Synthesis, Characterization, and Magnetic Studies of <svg style="vertical-align:-0.1638pt" height="8.1625004" version="1.1" viewBox="0 0 10.7375 8.1625004" width="10.7375" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.9)"><path id="x1D736" d="M505 450h125l-163 -259q-1 -4 -1 -12q0 -19 1 -23q9 -98 41 -98q36 0 58 76l24 -7q-34 -139 -121 -139q-32 0 -57.5 24t-31.5 55q-72 -77 -181 -77q-73 0 -114 44t-41 124q0 118 79 210q79 93 197 93q51 0 86 -27t50 -71zM369 281q0 141 -62 141q-43 0 -95 -84&#xA;q-52 -82 -52 -195q0 -50 15 -83t42 -33q35 0 79 57q43 58 67 121q6 35 6 76z" /></g></svg>-<svg style="vertical-align:-3.39064pt" height="15.65" version="1.1" viewBox="0 0 41.712502 15.65" width="41.712502" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.362)"><path id="x46" d="M493 503l-29 -4q-13 56 -28 80q-13 22 -35.5 29.5t-78.5 7.5h-76q-22 0 -27.5 -5t-5.5 -27v-238h103q66 0 82.5 12t25.5 62h29v-193h-29q-9 54 -25.5 67t-82.5 13h-103v-181q0 -64 15 -78.5t84 -19.5v-28h-272v28q61 5 74.5 19.5t13.5 78.5v399q0 64 -13 78t-72 19v28&#xA;h440q1 -40 10 -147z" /></g><g transform="matrix(.017,-0,0,-.017,9.055,11.362)"><path id="x65" d="M380 106l15 -22q-42 -52 -87 -74t-76 -22q-89 0 -142 62t-53 151q0 103 66 175q67 73 146 73h1q61 0 105.5 -46.5t44.5 -105.5q0 -16 -4.5 -22.5t-18.5 -9.5q-54 -10 -262 -17q1 -95 46 -143.5t104 -48.5q61 0 115 50zM225 412q-35 0 -64.5 -32.5t-40.5 -90.5q83 0 170 3&#xA;q14 0 19 4.5t5 15.5q1 41 -23.5 70.5t-65.5 29.5z" /></g><g transform="matrix(.012,-0,0,-.012,16.275,15.45)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g><g transform="matrix(.017,-0,0,-.017,22.613,11.362)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g><g transform="matrix(.012,-0,0,-.012,35.312,15.45)"><path id="x33" d="M285 378v-2q65 -13 102 -54.5t37 -97.5q0 -57 -30.5 -104.5t-74 -75t-85.5 -42t-72 -14.5q-31 0 -59.5 11t-40.5 23q-19 18 -16 36q1 16 23 33q13 10 24 0q58 -51 124 -51q55 0 88 40t33 112q0 64 -39 96.5t-88 32.5q-29 0 -64 -11l-6 29q77 25 118 57.5t41 84.5&#xA;q0 45 -26.5 69.5t-68.5 24.5q-67 0 -120 -79l-20 20l43 63q51 56 127 56h1q66 0 107 -37t41 -95q0 -42 -31 -71q-22 -23 -68 -54z" /></g></svg> Nanoparticles

The aim of this research is to improve the sensitivity of ammonia gas sensor (hereafter referred to as sensor) based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by employing the doping dye of bromocresol green (BCG). The doping process was carried out by mixing the BCG and the PEDOT:PSS in a solution with an optimum ratio of 1&#x2009;:&#x2009;1 in volume. The sensor was fabricated by using spin-coating technique followed by annealing process. For comparison, the BCG thin film and the PEDOT:PSS thin film were also deposited with the same method on glass substrates. For optical characterization, a red-light laser diode with a 650&#x2009;nm wavelength was used as light source. Under illumination with the laser diode, the bare glass substrate and BCG film showed no absorption. The sensor exhibited linear response to ammonia gas for the range of 200&#x2009;ppm to 800&#x2009;ppm. It increased the sensitivity of sensor based on PEDOT:PSS with BCG doping  being about twofold higher compared to that of without BCG doping. Furthermore, the response time and the recovery time of the sensor were found very fast. It suggests that the optical sensor based on BCG-doped PEDOT:PSS is promising for application as ammonia gas sensor.

La Aba

Yusril Yusuf

Mitrayana

Dwi Siswanta

Junaidi

Kuwat Triyana

Sensitivity Improvement of Ammonia Gas Sensor Based on Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) by Employing Doping of Bromocresol Green

Nanoparticles (NPs) have been introduced as a suitable alternative in many in vivo bioapplications. The risks of utilizing nanoparticles continue to be an ongoing research. Furthermore, the various chemicals used in their synthesis influence the cytotoxic effects of nanoparticles. We have investigated the cytotoxicity of Porous Hollow Au Nanoparticles (PHAuNPs) on cancer cell lines PC-3, PC-3ML, and MDA-MB-231 and the normal cell line PNT1A. Cell proliferation for the different cells in the presence of different concentrations of the PHAuNPs was assessed after 24 hours and 72 hours of incubation using MTT assay. The study also included the cytotoxic evaluation of pegylated PHAuNPs. Identical cell seeding densities, particle concentrations, and incubation times were employed for these two types of Au nanoparticles. Our results indicated that (1) impact on cell proliferation was concentration dependent and was different for the different cell types without cellular necrosis and (b) cellular proliferation might be impacted more based on the cell line.

Smitha Rao

Chienwen Huang

Uday Tata

Peter Wu

Nikhil Arora

Jinsung Ahn

Victor K. Lin

Yaowu Hao

J.-C. Chiao

Evaluation of Cytotoxic Effects of Different Concentrations of Porous Hollow Au Nanoparticles (PHAuNPs) on Cells

Nanosilver was synthesized using the aqueous solution of solvent extracts of leaf and stem of Kedrostis foetidissima. Three different methods of formation of silver nanoparticles such as reaction at (i) room temperature, (ii) higher temperature, and (iii) sonication were employed in the present study. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, X-ray diffractometer, Scherrer&#x2019;s formula, scanning electron microscopy, and FTIR analysis.

M. Amutha

P. Lalitha

M. Jannathul Firdhouse

Biosynthesis of Silver Nanoparticles Using Kedrostis foetidissima (Jacq.) Cogn.

Efficient silicon-based light emitters continue to be a challenge. A great effort has been made in photonics to modify silicon in order to enhance its light emission properties. In this aspect silicon nanocrystals (Si-NCs) have become the main building block of silicon photonic (modulators, waveguide, source, and detectors). In this work, we present an approach based on implantation of Ag (or Au) ions and a proper thermal annealing in order to improve the photoluminescence (PL) emission of Si-NCs embedded in SiO2. The Si-NCs are obtained by ion implantation at MeV energy and nucleated at high depth into the silica matrix (1-2&#x2009;&#x3bc;m under surface). Once Si-NCs are formed inside the SiO2 we implant metal ions at energies that do not damage the Si-NCs. We have observed by, PL and time-resolved PL, that ion metal implantation and a subsequent thermal annealing in a hydrogen-containing atmosphere could significantly increase the emission properties of Si-NCs. Elastic Recoil Detection measurements show that the samples with an enhanced luminescence emission present a higher hydrogen concentration. This suggests that ion metal implantation enhances the hydrogen diffusion into silica matrix allowing a better passivation of surface defects on Si NCs.

J. Bornacelli

J. A. Reyes-Esqueda

L. Rodr&#xed;guez-Fern&#xe1;ndez

J. L. Ruvalcaba-Sil

F. J. Jaimes

A. Oliver

Enhancing Hydrogen Diffusion in Silica Matrix by Using Metal Ion Implantation to Improve the Emission Properties of Silicon Nanocrystals

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Journal of Nanotechnology publishes papers related to the science and technology of nanosized and nanostructured materials, with emphasis on their design, characterization, functionality, and preparation for implementation in systems and devices.

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Journal of Nanotechnology - Table of contents 2014

title

Journal of Nanotechnology publishes papers related to the science and technology of nanosized and nanostructured materials, with emphasis on their design, characterization, functionality, and preparation for implementation in systems and devices.

Journal of Nanotechnology