bluuebunny/crossref_metadata_2025 huggingface dataset:
The Prospective Two-Dimensional Graphene Nanosheets: Preparation, Functionalization and Applications
Authors: Yang Zhi , Gao Rungang , Hu Nantao , Chai Jing , Cheng Yingwu , Zhang Liying , Wei Hao , Kong Eric Siu-Wai , Zhang Yafei
Published: October 2014

Graphene, as an intermediate phase between fullerene and carbon nanotube, has aroused much interests among the scientific community due to its outstanding electronic, mechanical, and thermal properties. With excellent electrical conductivity of 6000 S/cm, which is independent on chirality, graphene is a promising material for high-performance nanoelectronics, transparent conductor, as well as polymer composites. On account of its Young’s Modulus of 1 TPa and ultimate strength of 130 GPa, isolated graphene sheet is considered to be among the strongest materials ever measured. Comparable with the single-walled carbon nanotube bundle, graphene has a thermal conductivity of 5000 W/(m·K), which suggests a potential application of graphene in polymer matrix for improving thermal properties of the graphene/polymer composite. Furthermore, graphene exhibits a very high surface area, up to a value of 2630 m2/g. All of these outstanding properties suggest a wide application for this nanometer-thick, two-dimensional carbon material. This review article presents an overview of the significant advancement in graphene research: preparation, functionalization as well as the properties of graphene will be discussed. In addition, the feasibility and potential applications of graphene in areas, such as sensors, nanoelectronics and nanocomposites materials, will also be reviewed.
Terahertz Generation Using Implanted InGaAs Photomixers and Multi-wavelength Quantum Dot Lasers
Authors: Hou Y. , Liu J. R. , Buchanan M. , Thorpe A. J. Spring , Poole P. J. , Liu H. C. , Wu Ke , Roorda Sjoerd , Zhang X. P.
Published: October 2014

We report on a study of terahertz (THz) generation using implanted InGaAs photomixers and multi-wavelength quantum dot lasers. We carry out InGaAs materials growth, optical characterization, device design and fabrication, and photomixing experiments. This approach is capable of generating a comb of electromagnetic radiation from microwave to terahertz. For shortening photomixer carrier lifetime, we employ proton implantation into an epitaxial layer of lattice matched InGaAs grown on InP. Under a 1.55 μm multi-mode InGaAs/InGaAsP quantum dot laser excitation, a frequency comb with a constant frequency spacing of 50 GHz generated on the photomixer is measured, which corresponds to the beats of the laser longitudinal modes. The measurement is performed with a Fourier transform infrared spectrometer. This approach affords a convenient method to achieve a broadband multi-peak coherent THz source.
Electrochemical Synthesis and Photocatalytic Property of Zinc Oxide Nanoparticles
Authors: Chandrappa Kodihalli G. , Venkatesha Thimmappa V.
Published: October 2014

Zinc oxide (ZnO) nanoparticles of varying sizes (20, 44 and 73 nm) have been successfully synthesized by a hybrid electrochemical-thermal method using aqueous sodium bicarbonate electrolyte and sacrificial Zn anode and cathode in an undivided cell under galvanostatic mode at room temperature. The as-synthesized product was characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Scanning electron microscopy along with Energy dispersive analysis of X-ray (SEM/EDAX), Transmission electron microscopy (TEM), Ultra Violet - Diffuse reflectance spectroscopic methods (UV-DRS). and UV-DRS spectral methods. The as-synthesized compound were single-crystalline and Rietveld refinement of calcined samples exhibited hexagonal (Wurtzite) structure with space group of P63mc (No.186). The band gaps for synthesized ZnO nanoparticles were 3.07, 3.12 and 3.13 eV, respectively, based on the results of diffuse reflectance spectra (DRS). The electrochemically synthesized ZnO powder was used as photocatalysts for UV-induced degradation of Methylene blue (MB). Photodegradation was also found to be function of exposure time and dye solution pH. It has been found that as-synthesized powder has excellent photocatalytic activity with 92% degradation of MB, indicating ZnO nanoparticles can play an important role as a semiconductor photocatalyst.
Assembling ZnO Nanorods into Microflowers through a Facile Solution Strategy: Morphology Control and Cathodoluminescence Properties
Authors: Lei Ying , Qu Fengyu , Wu Xiang
Published: October 2014

In this work, flowerlike ZnO micro/nanostructures assembled from nanorods are obtained through a facile hydrothermal route. The experimental results indicated that the as-synthesized ZnO microflowers have an average diameter of 2 µm, composed of nanorods of an average diameter of 200 nm and a tapered morphology. ZnO with other morphologies were also obtained by varying the reaction conditions. Systematical condition-dependent experiments were conducted to reveal the growth mechansim of the microflowers. It is suggested that the zinc source types, solution pH value, and reaction temperature, as well as reaction time are responsible for the variations of ZnO morphology. Luminescence properties of ZnO microflowers were investigated through monitoring different parts of nanorods, showing good optical quality.
One-Step Synthesis and Photoluminescence Evaluation of Cadmium-Containing Quantum Dots
Authors: Shukla Nisha , Nigra Michael M. , Ondeck Abigail D.
Published: October 2014

We have developed a simple one-step process for synthesis of ternary quantum dots (ZnCdSe, MgCdSe) with photoluminescence wavelengths ranging from the red to the blue region of the visible spectrum. The primary aim of this work was to develop a synthesis for the preparation of Cd-containing quantum dots using a Cd precursor with lower toxicity than those used in common syntheses. This synthesis makes use of Cd(acac)2 which is significantly less toxic than precursors such as CdO and CdCl2. We have studied the effect of solvent boiling point, precursors and reaction time on the photoluminescence properties of the ternary quantum dots. Ternary quantum dots synthesized from Cd(acac)2in low boiling point solvents have photoluminescence wavelengths in the blue region, while those synthesized in high boiling point solvents have photoluminescence wavelengths in the red region.
Application of Modified Silica Coated Magnetite Nanoparticles for Removal of Iodine from Water Samples
Authors: Madrakian Tayyebeh , Afkhami Abbas , Zolfigol Mohammad Ali , Ahmadi Mazaher , Koukabi Nadia
Published: October 2014

The adsorption of iodine onto silica coated magnetite nanoparticles (im-SCMNPs) that modified with imidazole was investigated for removal of high concentrations of iodine from wastewater. Modified silica magnetite nanoparticles showed high efficiency in removing iodine from wastewater samples. The optimum pH for iodine removal was 7.0–8.0. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. The size of the produced magnetite nanoparticles was determined by X-ray diffraction analysis and scanning electron microscopy. Synthesized magnetite nanoparticles showed the high adsorption capacity and would be a good method to increase adsorption efficiency for the removal of iodine in a wastewater treatment process. The Langmuir adsorption capacity (qmax) was found to be 140.84 mg/g of the adsorbent.
Synthesis and Characterization of Rare Earth Ion Doped Nano ZnO
Authors: John Rita , Rajakumari Rajaram
Published: October 2014

Zinc oxide (ZnO) doped with erbium at different concentrations was synthesized by solid-state reaction method and characterized by X-ray diffraction (XRD), scanning electron microscopic (SEM), UV-absorption spectroscopy, photoluminescence (PL) study and vibrating sample magnetometer. The XRD studies exhibit the presence of wurtzite crystal structure similar to the parent compound ZnO in 1% Er3+ doped ZnO, suggesting that doped Er3+ ions sit at the regular Zn2+ sites. However, same studies spread over the samples with Er3+ content>1% reveals the occurrence of secondary phase. SEM images of 1% Er3+ doped ZnO show the polycrystalline nature of the synthesized sample. UV-visible absorption spectrum of Er3+ doped ZnO nanocrystals shows a strong absorption peak at 388 nm due to ZnO band to band transition. The PL study exhibits emission in the visible region, due to excitonic as well as defect related transitions. The magnetization-field curve of Er3+ doped ZnO nanocrystals showed ferromagnetic property at room-temperature.
Solid-State Synthesis and Effect of Temperature on Optical Properties of CuO Nanoparticles
Authors: Vidyasagar C. C. , Arthoba Naik Y. , Venkatesha T. G. , Viswanatha R.
Published: October 2014

Modulation of band energies through size control offers new ways to control photoresponse and photoconversion efficiency of the solar cell. The P-type semiconductor of copper oxide is an important functional material used for photovoltaic cells. CuO is attractive as a selective solar absorber since it has high solar absorbance and a low thermal emittance. The present work describes the synthesis and characterization of semiconducting CuO nanoparticles via one-step, solid-state reaction in the presence of Polyethylene glycol 400 as size controlling agent for the preparation of CuO nanoparticles at different temperatures. Solid-state mechanochemical processing, which is not only a physical size reduction process in conventional milling but also a chemical reaction, is mechanically activated at the nanoscale during grinding. The present method is a simple and efficient method of preparing nanoparticles with high yield at low cost. The structural and chemical composition of the nanoparticles were analyzed by X-ray diffraction, field emission scanning electron microscopy and energy-dispersive spectrometer, respectively. Optical properties and band gap of CuO nanoparticles were studied by UV-Vis spectroscopy. These results showed that the band gap energy decreased with increase of annealing temperature, which can be attributed to the improvement in grain size of the samples.
Effect of Synthesis Method on Photoluminescence Properties of Na2Sr2Al2PO4Cl9:Ce3+ Nanophosphor
Authors: Shinde K. N. , Dhoble S. J. , Park K.
Published: October 2014

We have synthesized a series of single-composition emission Na2Sr2Al2PO4Cl9:Ce3+ phosphor by traditional solid state reactions and novel combustion method. Formation of compound was confirmed by X-ray diffraction analysis. The photoluminescence (PL) emission spectra were observed at 376 nm when excited around 322 nm for the various concentrations in both cases. The PL emission spectra of phosphors showed strong Ce3+ emission due to the 5d→4f transition of Ce3+ ions. The Ce3+ emission intensity in Na2Sr2Al2PO4Cl9:Ce3+ prepared by combustion was higher than that of solid state reactions.
Controllable Hydrothermal Synthesis and Properties of ZnO Hierarchical Micro/Nanostructures
Authors: Li Weifei , Sun Yangang , Xu Jingli
Published: October 2014

A simple hydrothermal route has been developed for the fabricating ZnO hierarchical micro/nanostructure with excellent reproducibility. SEM and TEM analysis show that the hierarchical rod is a single-crystal, suggesting that many single-crystal micro/nanorods are assembled into ZnO hierarchical micro/nanostructures. The morphologies of the hierarchical rods can be conveniently tailored by changing the reaction parameters. And we also found citric acid plays a crucial role in the formation process of ZnO micro/nanostructures. Room-temperature photoluminescence spectra reveals that the ZnO hierarchical micro/nanostructures have a strong emission peak at 440 nm and several weak emission peaks at 420, 471 and 541 nm, respectively.
Using Inductance as a Tuning Parameter for RF Meta-atoms
Authors: Langley Derrick , Coutu Ronald A. , Collins Peter J.
Published: October 2014

The resonant frequency of metamaterials structured with split ring resonator (SRR) meta-atoms is determined primarily through the capacitance and inductance of the individual meta-atoms. Two designs that vary inductance incrementally were modeled, simulated, fabricated, and tested to investigate the role inductance plays in metamaterial designs. The designs consisted of strategically adding sections to the SRR to increase the inductance, but in a manner that minimized capacitance variations. Each design showed a shift in resonant frequency that was proportional to the length of the added section. As the length of each section was increased, the resonant frequency shifted from 2.78 GHz to 2.18 GHz.
Cavity Control of Prefoldin Nano Actuator (PNA) by Temperature and pH
Authors: Shokuhfar Ali , Ghaffari Ali , Ghasemi Reza Hasanzadeh
Published: October 2014

A molecular dynamics study to investigate the cavity control of Prefoldin based bio nano actuator is presented in this paper. Prefoldin is a molecular chaperone with a jellyfish-like structure containing six long coiled-coil tentacles and a large central cavity. We took the temperature and pH of the medium into account, and analyzed the conformational flexibility of the Prefoldin nano actuator in details. Results show that the prefoldin is a very flexible protein, the conformational state of which appears to depend on the temperature and pH values of the medium. In fact, combining these two control parameters, a suitable environment is provided to capture nano cargoes with specific dimensions. These properties of Prefoldin actuator can be used for drug delivery in the body.
Micro and Nanotechnology for Intracellular Delivery Therapy Protein
Authors: Xu Dan , Hu Zhenhua , Su Jing , Wu Fei , Yuan Weien
Published: October 2014

Proteins therapy is of great importance in the treatment of protein deficiency disease. Most human diseases are related to the malfunctioning of one or more proteins. The most effective and direct approach is protein therapy, which delivers the proteins into the target cell to replace the dysfunction protein and maintain the balance of organism. However, clinical application is frequently hampered by various biological barriers to their successful delivery. This review aims to discuss the recent advances about microparticles and nanoparticles fabricated using micro and nanotechnology for intracellular delivery therapy protein and give some suggestions about the promising delivery system.
Development of Inorganic Solar Cells by Nano-technology
Authors: Zhang Yafei , Geng Huijuan , Zhou Zhihua , Wu Jiang , Wang Zhiming , Zhang Yaozhong , Li Zhongli , Zhang Liying , Yang Zhi , Hwang HueyLiang
Published: October 2014

Inorganic solar cells, as durable photovoltaic devices for harvesting electric energy from sun light, have received tremendous attention due to the fear of exhausting the earth’s energy resources and damaging the living environment due to greenhouse gases. Some recent developments in nanotechnology have opened up new avenues for more relevant inorganic solar cells produced by new photovoltaic conversion concepts and effective solar energy harvesting nanostructures. In this review, the multiple exciton generation effect solar cells, hot carrier solar cells, one dimensional material constructed asymmetrical schottky barrier arrays, noble nanoparticle induced plasmonic enhancement, and light trapping nanostructured semiconductor solar cells are highlighted.
Effect of Silver Nanoparticles on Growth of Eukaryotic Green Algae
Authors: Dash Anjali , Singh Anand P. , Chaudhary Bansh R. , Singh Sunil K. , Dash Debabrata
Published: October 2014

Silver nanoparticles, endowed with powerful antimicrobial property, are the most widely used nanomaterial in consumer products, with associated risk of their easy access to environment and freshwater ecosystems by surface runoff. Although toxic effects of nanosilver on bacterial, fungal and mammalian cells have been documented, its impact on algal growth remains unknown. Pithophora oedogonia and Chara vulgaris are predominant members of photosynthetic eukaryotic algae, which form major component of global aquatic ecosystem. Here we report for the first time that nanosilver has significant adverse effects on growth and morphology of these filamentous green algae in a dose-dependent manner. Exposure of algal thalli to increasing concentrations of silver nanoparticles resulted in progressive depletion in algal chlorophyll content, chromosome instability and mitotic disturbance, associated with morphological malformations in algal filaments. SEM micrographs revealed dramatic alterations in cell wall in nanoparticle-treated algae, characterized with cell wall rupture and degradation in Pithophora. Although these observations underscore severe deleterious effects of nanosilver on aquatic environment, the information can also be exploited as a bioengineering strategy to control unwanted and persistent growth of noxious algal weeds that clog the municipal water supply and water channels and produce fouling of water bodies.
Compositionally Graded Microstructure for Ag-Fe Nanoparticles
Authors: Srivastava Chandan , Sushma K. V. L.
Published: October 2014

Ag-Fe nanoparticles with a highly Ag rich average composition were synthesized by the sonochemical route. Silver-iron system exhibits a wide miscibility gap in the bulk materials. Interestingly, a graded compositional profile along the nanoparticle radius was observed. Regions at and near the surface of the nanoparticle contained both Ag and Fe atoms. The composition got relatively deficient Fe towards the center of the particle with particle core made up of pure Ag. Alloying of Ag and Fe is confirmed by the absence of diffraction signal corresponding to pure Fe phase and presence of a paramagnetic phase in nanoparticles containing a diamagnetic (Ag) and ferromagnetic (Fe) elements.
4-Aminothiophenol Strong SERS Signal Enhancement at Electrodeposited Silver Surface
Authors: Škantárová Lenka , Oriňák Andrej , Oriňáková Renáta , Lofaj František
Published: October 2014

Strong surface enhancement Raman spectroscopy signal of 4-aminothiophenol on silver substrate prepared by controlled electrodeposition is documented in this article. Enhancement factor was found to be affected not only by nanoparticle size, shape, orientation and spatial distribution, but also by interaction of Ag nanoparticles with thiol group of testing analyte. Self-assembled monolayers formation was contributed to this unique signal enhancement. The enhancement factor was established of 1.81×1014.
The Influence of Morphology on Photo-catalytic Activity and Optical Properties of Nanocrystalline ZnO Powder
Authors: Moghaddam Javad , Mollaesmail Sara , Karimi Saeed
Published: October 2014

ZnO nano-particles were synthesized via an ammonical ammonium carbonate solution by precipitation method in presence of some additives such as urea, oleic and stearic acid. The morphology and crystallinity of the obtained zinc oxide particles depend critically on the type of additive which was used. Additives also affected the crystal orientation of precipitate nano-particles. SEM, XRD, BET and UV-visible were used to characterize morphology, microstructure, specific surface area and optical properties of the products. Photo-catalysis properties of the as-prepared ZnO powders were evaluated by degradation of methyl red (acid red) in aqueous solution exposed to UV-light. Results suggested a close relationship among the morphology, size and surface area on photo-catalysis and optical properties of the particles. The widest Eg value (3.56 eV), highest degradation and decolorization efficiency (99%) were obtained from a sample with the smallest grain size (largest surface area) which were used urea as an additive.
Controlling the Properties of Solvent-free Fe3O4 Nanofluids by Corona Structure
Authors: Tan Yumo , Zheng Yaping , Wang Nan , Zhang Aibo
Published: October 2014

We studied the relationship between corona structure and properties of solvent-free Fe3O4 nanofluids. We proposed a series of corona structures with different branched chains and synthesize different solvent-free nanofluids in order to show the effect of corona structure on the phase behavior, dispersion, as well as rheology properties. Results demonstrate novel liquid-like behaviors without solvent at room temperature. Fe3O4 magnetic nanoparticles content is bigger than 8% and its size is about 2∼3 nm. For the solvent-free nanofluids, the long chain corona has the internal plasticization, which can decrease the loss modulus of system, while the short chain of corona results in the high viscosity of nanofluids. Long alkyl chains of modifiers lead to lower viscosity and better flowability of nanofluids. The rheology and viscosity of the nanofluids are correlated to the microscopic structure of the corona, which provide an in-depth insight into the preparing nanofluids with promising applications based on their tunable and controllable physical properties.
Assembling SnO Nanosheets into Microhydrangeas: Gas Phase Synthesis and Their Optical Property
Authors: Zhang Zhenglin , Wang Jing , Yu Zhou , Qu Fengyu , Wu Xiang
Published: October 2014

Large scale SnO microhydrangeas are obtained successfully through thermally evaporating of SnO2 powder wrapped by a filter paper at 1050°C and using gold coated Si wafer as the substrate. The as-obtained SnO microhydrangeas are consisted of many thin nanosheets with the thicknesses of 30–60 nm and the diameters of 500–600 nm. A vapor-liquid-solid (VLS) growth mechanism for the as-synthesized SnO microhydrangeas was proposed based on experimental results. Photoluminescence spectrum (PL) shows that there is a strong sharp ultraviolet emission peak at 390 nm, revealing that these three-dimensional SnO microhydrangeas may have potential applications in optoelectronic fields.
Nanobiocomposite Electrochemical Biosensor Utilizing Synergic Action of Neutral Red Functionalized Carbon Nanotubes
Authors: Jeykumari D. R. Shobha , Kalaivani R. , Narayanan S. Sriman
Published: October 2014

An amperometric hydrogen peroxide biosensor using a nanobiocomposite based on neutral red modified carbon nanotubes and co-immobilized glucose oxidase and horseradish peroxidase is reported. Modification of the nanobiocomposite electrode with neutral red resulted in a sensitive, low-cost and reliable H2O2 sensor. The use of carbon nanotubes, as the conductive part of the composite, facilitated fast electron transfer rates. The biosensor was characterized for the influence of pH, potential and temperature. A remarkable feature of the biosensor is the detection of H2O2 at low applied potentials where the noise level and interferences are minimal. The sensor has a fast steady-state measuring time of 10 s with a quick response (2 s). The biosensor showed a linear range from 15 nM to 45 mM of H2O2 and a detection limit of 5 nM. Nafion, which is used as a binder, makes the determination free from other electroactive substances. The repeatability, reproducibility, stability and analytical performance of the sensor are very good.
Shell-driven Fine Structure Transition of Core Materials in Co@Au Core-shell Nanoparticles
Authors: Song Yujun , Wang Yinghui , Ji Shaoxia , Ding Jie
Published: October 2014

Co@Au core shell nanoparticles (NPs) of different shell thicknesses were fabricated by a combination of the displacement process and the reduction-deposition process in a microfluidic reactor. The effect of the shell thickness on the fine structures (local atom arrangement) of core materials was investigated by X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS). The results indicate that the shell thickness affects the fine structure of the core materials by causing atomic re-arrangement between the hexagonal close pack (hcp) and the face centered cubic (fcc) structure, and forming Co-Au bonds in the core-shell interface.
Ordered SrTiO3 Nanoripples Induced by Focused Ion Beam
Authors: Wu Jiang , Chen Gang , Zeng Zhaoquan , Li Shibin , Xu Xingliang , Wang Zhiming M. , Salamo Gregory J.
Published: October 2014

Ordered nanoripples on the niobium-doped SrTiO3 surfaces were fabricated through focused ion beam bombardment. The surface morphology of the SrTiO3 nanoripples was characterized using in situ focused ion beam/scanning electron microscopy. The well-aligned SrTiO3 nanostructures were obtained under optimized ion irradiation conditions. The characteristic wavelength was measured as about 210 nm for different ion beam currents. The relationship between the ion irradiation time and current and SrTiO3 surface morphology was analyzed. The presented method will be an effective supplement for fabrication of SrTiO3 nanostructures that can be used for ferroelectric and electronic applications.
Electrophoretic Carbon Nanotube Field Emission Layer for Plasma Display Panels
Authors: Liu Qifa , Yang Zhuoqing , Wang Yan , Ding Guifu
Published: October 2014

A carbon-nanotube (CNT) electrophoretic deposition (EPD) process has been developed to prepare a field emission layer in plasma display panels (PDP) for discharge voltage reduction. The CNT layer as a source of discharge priming electrons has been fabricated on the PDP front panel. The balling grinding, mix-acid treatment and EPD parameters have been investigated in order to obtain good uniformity and excellent field emission capability of CNT layer, in order to meet the specifications of CNTs in PDP cell. The measured turn-on field was around 1.1 V/μm in the field emission testing while the minimum sustaining voltage was decreased by 30∼40 V with the use of CNT layer in the discharge testing.
Synthesis, Optical Properties and Photovoltaic Application of the SnS Quasi-one-dimensional Nanostructures
Authors: Wang M. X. , Yue G. H. , Lin Y. D. , Wen X. , Peng D. L. , Geng Z. R.
Published: October 2014

Low-toxicity single crystal SnS nanowires had been successfully synthesized by the catalyst-assistant chemical vapor deposition. Au nanoparticles were applied on the ITO surface as the catalysis, using SnS powder and S powder as forerunners. The structure, morphology and optical properties of the prepared SnS nanowires were characterized. The experimental results show the as-synthesized nanowires are single crystalline with a preferential orientation. The synthesized SnS nanowires show strong absorption in the visible and near-infrared spectral region, and the direct energy band gap of SnS nanowires is 1.46 eV.
Large-scale Patterning of Hydrophobic Silicon Nanostructure Arrays Fabricated by Dual Lithography and Deep Reactive Ion Etching
Authors: Ma Zhibo , Jiang Chengyu , Yuan Weizheng , He Yang
Published: October 2014

We describe a simple but efficient technique to fabricate large-scale arrays of highly ordered silicon nanostructures. By coupling dual lithography using light of 351.1 nm wavelength with deep reactive ion etching (DRIE), silicon nanostructures of excellent regularity and uniform coverage were achieved. The proposed nanofabrication method not only simplified the nanofabrication process but also produced high-aspect-ratio (higher than 15) nanostructures. The scalloping problem was also controlled by regulating DRIE parameters. The process is rapid, cheap, examined to optimize the fabrication process, and has the potential to be scaled up to large areas. The contact angle of a water droplet atop the surface is larger than 15°. Moreover, by coupling black silicon process with DRIE-based microfabrication, three-dimensional nano/nano dual-scale structures which show robust and stable hydrophobicity have been achieved. This process opens new application possibilities in optical, photoelectric, microelectronic, catalytic and biomedical applications.
Influence of an Electronic Field on the GMI Effect of Fe-based Nanocrystalline Microwire
Authors: Zhang Q. , Chen D. L. , Li X. , Yang P. X. , Chu J. H. , Zhao Z. J.
Published: October 2014

In this work, a Fe-based nanocrystalline microwire of 20 mm in length and 25 μm in diameter was placed in the center of a 316 stainless steel pipe. The pipe was 500 μm in diameter and a little shorter than the microwire. A series of voltages were applied on the pipe to study the influence of the electrical field on the Giant-Magneto-Impedance (GMI) effect of the microwire. Experimental results showed that the electronic field between the wire and the pipe reduced the hysteresis of the GMI effect. The results were explained based on equivalent circuit and eddy current consumptions analysis.
Synthesis of Nanostructured Copper-doped Titania and Its Properties
Authors: Zuas Oman , Budiman Harry
Published: October 2014

Nanostructured pure-TiO2and Cu3%-TiO2were successfully synthesized via co-precipitation method. The X-ray diffraction (XRD) result proves that the synthesized sample were predominantly in anatase phase with size in the range of 8∼16 nm, which are in good agreement with the transmission electron microscopy data. Owing to doping of copper, not only did the thermal stability of the TiO2decrease, but also a significant decrease in its particle size and a shift of the adsorption edge to a higher wavelength region appear. The activity of both pure-TiO2and Cu3%-doped TiO2was tested to study their ability to decolorize congo red (CR) dye in aqueous solution. We observed that the CR dye was decolorized faster by Cu3%-TiO2than pure-TiO2. Results of this study demonstrate a potential application of the synthesized sample for decolorizing dye pollutants from aqueous waste.
Semiconductor Type Dependent Comparison of Electrical Characteristics of Pt/InP Structures Fabricated by Magnetron Sputtering Technique in the Range of 20–400 K
Authors: Korkut H.
Published: October 2014

The paper describes how electrical properties of Pt/InP Schottky diode were affected by semiconductor type. We fabricated Pt/p-InP and Pt/n-InP Schottky diodes and measured electrical characteristics from 20 K to 400 K. Thicknesses of less than 30 nm of platinum were deposited on the two types of indium phosphide substrates using magnetron sputtering technique after the creation of Zn-Au ohmic back contact. We discussed basic diode parameters of idealiy factors, barrier heights and serries resistances of the two type of contacts. Additionly, unusual temperature characteristics of the the diodes were highlighted. These results were evaluated in terms of semiconductor type comparision of Pt/InP Schottky structures.
Vapor Phase Polymerization Deposition Conducting Polymer Nanocomposites on Porous Dielectric Surface as High Performance Electrode Materials
Authors: Yang Yajie , Zhang Luning , Li Shibin , Wang Zhiming , Xu Jianhua , Yang Wenyao , Jiang Yadong
Published: October 2014

We report chemical vapor phase polymerization (VPP) deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) and PEDOT/graphene on porous dielectric tantalum pentoxide (Ta2O5) surface as cathode films for solid tantalum electrolyte capacitors. The modified oxidant/oxidant-graphene films were first deposited on Ta2O5 by dip-coating, and VPP process was subsequently utilized to transfer oxidant/oxidant-graphene into PEDOT/PEDOT-graphene films. The SEM images showed PEDOT/PEDOT-graphene films was successfully constructed on porous Ta2O5 surface through VPP deposition, and a solid tantalum electrolyte capacitor with conducting polymer-graphene nano-composites as cathode films was constructed. The high conductivity nature of PEDOT-graphene leads to resistance decrease of cathode films and lower contact resistance between PEDOT/graphene and carbon paste. This nano-composite cathode films based capacitor showed ultralow equivalent series resistance (ESR) ca. 12Ω and exhibited excellent capacitance-frequency performance, which can keep 82% of initial capacitance at 500 KHz. The investigation on leakage current revealed that the device encapsulation process has no influence on capacitor leakage current, indicating the excellent mechanical strength of PEDOT/PEDOT-gaphene films. This high conductivity and mechanical strength of graphene-based polymer films shows promising future for electrode materials such as capacitors, organic solar cells and electrochemical energy storage devices.
Recent Progress in Ferroelectric Diodes: Explorations in Switchable Diode Effect
Authors: Ge Chen , Wang Can , Jin Kui-juan , Lu Hui-bin , Yang Guo-zhen
Published: October 2014

Switchable diode effect in ferroelectric diodes has attracted much attention for its potential applications in novel nonvolatile memories. We briefly review recent investigations on the switchable diode effect in ferroelectric diodes both experimentally and theoretically. Many recent studies demonstrate that the interfacial barrier between the metal-ferroelectrics could be modulated by the polarization charges, and the ferroelectric polarization that can be reversed by an external electric field plays a dominant role in the switchable diode effect. Moreover, we review a self-consistent numerical model, which can well describe the switchable diode effect in ferroelectric diodes. Based on this model, it can be predicted that it is a better choice to select metals with a smaller permittivity, such as noble metals, to obtain a more pronounced switchable diode effect in ferroelectric diodes.
Nano Brazing of Pt-Ag Nanoparticles under Femtosecond Laser Irradiation
Authors: Liu L. , Huang H. , Hu A. , Zou G. , Quintino L. , Zhou Y.
Published: October 2014

Nano brazing of Pt-Ag nanoparticles with nano Ag filler metal is reported in this letter, which presents an effective way to join nanoobjects by femtosecond laser irradiation. The nano brazed interface between Pt-Ag and Ag showed good lattice matching along (111)Ag//(111)Ag-Pt. Lattice mismatch can hardly be observed at the interface between the filler metal and Pt-Ag nanoparticle, which is important for the joint strength and normally does not occur during joining. The very low mismatch also suggested that melting and solidification occurred during nano brazing by femtosecond laser. The role of Brownian motion on the nano joining process is also discussed in this paper.
Synthesis and Growth Mechanism of Net-like Titanate Nanowire Films via Low-temperature and Low-alkali-concentration Route
Authors: Huang Xinwen , Liu Zongjian
Published: October 2014

Net-like titanate nanowire films can be grown on Ti substrates by non-hydrothermal treatment of Ti foils in alkali-H2O2 aqueous solutions with a low alkali concentration of 2 M at 60–80°C. The growth mechanism of such films has been investigated by identifying the role of both H2O2 and alkali in the nanowire formation and capturing the film morphology at early growth stages. It is found that the presence of H2O2 is necessary for the nanowire growth, and sufficient amount of H2O2 is needed to produce well-shaped nanowires. The nanowire growth is also strongly dependant on the alkali used, and nanowire films are formed only when metal hydroxides which can react with TiO2 to form layer-structured titanates are chosen. Our results have also revealed that the heterogeneous deposition of titanate on Ti substrate results in the growth of titanate sheets, and the nanowire formation is via a splitting process by which each titanate sheet gradually evolves into nanowire thin layer. Based on the experimental results, a detailed mechanism is proposed for the growth of titanate nanowire films in alkali-H2O2 aqueous solutions at low temperature.
Electrochemical Generation of Cubic Shaped Nano Zn2SnO4 Photocatalysts
Authors: Govindappa Chandrappa K. , Venkatarangaiah Venkatesha T. , Hamid Sharifah B. Abd
Published: October 2014

In this contribution, an efficient and simple two-step hybrid electrochemical-thermal route was developed for the synthesis of cubic shaped Zn2SnO4 (ZTO) nanoparticles using aqueous sodium bicarbonate (NaHCO3) and sodium stannate (Na2SnO3) electrolyte. The sacrificial Zn was used as anode and cathode in an undivided cell under galvanostatic mode at room temperature. The bath concentration and current density were respectively varied from 30 to 120 mmol and 0.05 to 1.5 A/dm2. The electrochemically generated precursor was calcined for an hour at different range of temperature from 60 to 600°C. The crystallite sizes in the range of 24-53 nm were calculated based on Debye-Scherrer equation. Scanning electron microscope and transmission electron microscopy results reveal that all the particles have cubic morphology with diameter of 40–50 nm. The as-prepared ZTO samples showed higher catalytic activity towards the degradation of methylene blue (MB) dye, and 90% degradation was found for the sample calcined at 600°C, which is greater than that of commercial TiO2-P25 photocatalysts. The photodegradation efficiency of ZTO samples was found to be a function of exposure time and the dye solution pH value. These results indicate that the ZTO nanoparticles may be employed to remove dyes from wastewater.
Synthesis and Luminescence Properties of (Y, Gd) (P, V)O4:Eu3+, Bi3+Red Nano-phosphors with Enhanced Photoluminescence by Bi3+, Gd3+ Doping
Authors: Pu Yong , Tang Ke , Zhu Da-Chuan , Han Tao , Zhao Cong , Peng Ling-Ling
Published: October 2014

A series of (Y1−y
, Gd
y
)0.95−x
(P
y
, V1−y
)O4:0.05Eu3+, xBi3+ phosphors have been successfully prepared by a subsection method. The crystal structure, surface morphology and luminescence properties were investigated. It was found that the sintered samples crystallized in a tetragonal crystal system with space group I41/amd(a = b = 0.7119 nm, c = 0.6290 nm). The products presented rod-like morphology with length of 100–150 nm and width of 50–100 nm. A maximum peak at 619 nm (5D0 →7F2) was observed in emission spectrum of the phosphors. It was also found that co-doping of Bi3+, P5+ and Gd3+ions into YVO4:Eu3+ can not only made the right edge of the excitation band shift to the long-wavelength region, but also increased the emission intensity at 619 nm sharply and decreased the lifetime of fluorescence decay. These results may expand the application scope of the phosphors.
Growth and Formation Mechanism of Branched Carbon Nanotubes by Pyrolysis of Iron(II) Phthalocyanine
Authors: Wei Qiong , Liu Yunyun , Zhang Lijie , Huang Shaoming
Published: October 2014

In this letter, a route for synthesizing vertically aligned multi-walled carbon nanotubes (MWCNTs) with branched nanotubes in large area was reported. The branched MWCNTs up to about 30% can be generated by the pyrolysis of iron(II) phthalocyanine in presence of thiol under Ar/H2 at 800∼900°C. The growth mechanism of the branched nanotubes was proposed and the possible reason that thiol enhanced branched nanotubes growth is discussed. The as-prepared samples provide a suitable candidate to investigate the special electrical or thermal properties of CNTs with branched structures further.
Thermal Evaporation Deposition of Few-layer MoS2 Films
Authors: Ma Xiying , Shi Miaoyuan
Published: October 2014

We present a study of the fabrication of monolayer MoS2 on n-Si (111) substrates by modified thermal evaporation deposition and the optoelectrical properties of the resulting film. The as-grown MoS2 ultrathin film is about 10 nm thick, or about a few atomic layers of MoS2. The film has a large optical absorption range of 300–700 nm and strong luminescence emission at 682 nm. The optical absorption range covered almost the entire ultraviolet to visible light range, which is very useful for making high-efficiency solar cells. Moreover, the MoS2/Si heterojunction exhibited good rectification characteristics and excellent photovoltaic effects. The power conversion efficiency of the heterojunction device is about 1.79% under white light illumination of 10 mW/cm2. The results show that the monolayer MoS2 film will find many applications in high-efficiency optoelectronic devices.
Indocyanine Green Nanoparticles for Theranostic Applications
Authors: Sheng Zonghai , Hu Dehong , Xue Miaomiao , He Meng , Gong Ping , Cai Lintao
Published: October 2014

Theranostics is a concept that integrated imaging and therapy. As an emerging field, it embraces multiple techniques to arrive at an individualized treatment purpose. Indocyanine green (ICG) is a near infrared dye that has been approved by Food and Drug Administration (FDA) in USA for the use in indicator-dilution studies in humans. ICG nanoparticles (NPs) have attracted much attention for its potential applications in cancer theranostics. This review focuses on the preparation, application of ICG NPs for in vivo imaging (fluorescent imaging and photoacoustic imaging) and therapeutics (photothermal therapy, photodynamic therapy and photoacoustic therapy), and future directions based on recent developments in these areas. It is hoped that this review might provide new impetus to understand ICG NPs for cancer theranostics.
A Cu/ZnO Nanowire/Cu Resistive Switching Device
Authors: Li Lijie , Zhang Yan , Chew Zhengjun
Published: October 2014

A new device has been realized using flip-chip joining two printed circuit boards (PCBs) on which zinc oxide (ZnO) nanowires were synthesized. Energy dispersive X-ray measurement has been conducted for the ZnO nanowires, confirming that Cu elements have been diffused into the nanowires during the chemical growth process. From I–V measurements, this Cu/ZnO nanowire/Cu structure exhibits a resistive tuning behaviour, which varies greatly with the frequency of the applied sinusoidal source.
Algebraic Current-voltage and Voltage Dependent Resistance Expressions for Ballistic Nano Conductors and Their Low Voltage Nonlinearity
Authors: Yamacli Serhan
Published: October 2014

In this study, an algebraic current-voltage (I–V) equation suitable for the hand-calculation of ballistic nano conductors is derived from Landauer’s formulation. A voltage and temperature dependent resistance expression is also obtained. It is shown that the presented algebraic I–V expression and the original Landauer’s formula give the same characteristics as expected. Moreover, the I–V characteristics of ballistic nano conductors are investigated and it is concluded that there is an inescapable nonlinearity originating from the curvature of Fermi-Dirac distribution function in low voltage range. Finally, the total harmonic distortion (THD) of a sample ballistic nano conductor caused from its low voltage nonlinearity is computed via HSPICE simulations.
A Novel Immunosensor Based on Au Nanoparticles and Polyaniline/Multiwall Carbon Nanotubes/Chitosan Nanocomposite Film Functionalized Interface
Authors: Sun Xia , Qiao Lu , Wang Xiangyou
Published: October 2014

A novel multilayer film based on Au nanoparticles (AuNPs) and polyaniline/carboxylated multiwall carbon nanotubes-chitosan nanocomposite (PANI/MWCNTs/CS) was exploited to fabricate a highly sensitive immunosensor for detecting chlorpyrifos. PANI-coated MWCNTs were prepared by in situ chemical polymerization and carboxylated MWCNTs played an important role in obtaining the thin and uniform coating of PANI resulting in the improved immunosensor response. AuNPs were used as a linker to immobilize chlorpyrifos antibody. The performance of the immunosensor was characterized by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM), respectively. All variables involved in the preparation process and analytical performance of the immunosensor were optimized. Under optimal conditions (antibody concentration: 5 μg/ml, working buffer pH: 6.5, incubation time: 40 min, incubation temperature: 25°C), the immunosensor exhibited a wide linear range from 0.1 to 40×10−6 mg/ml and from 40×10−6 mg/ml to 500×10−6 mg/ml, and with a detection limit of 0.06×10−6 mg/ml, which provided a valuable tool for the chlorpyrifos detection in real samples.
Palladium Nanoparticles Loaded on Carbon Modified TiO2 Nanobelts for Enhanced Methanol Electrooxidation
Authors: Liang Robert , Hu Anming , Persic John , Zhou Y. Norman
Published: October 2014

Carbon modified TiO2nanobelts (TiO2-C) were synthesized using a hydrothermal growth method, as a support material for palladium (Pd) nanoparticles (Pd/TiO2-C) to improve the electrocatalytic performance for methanol electrooxidation by comparison to Pd nanoparticles on bare TiO2nanobelts (Pd/TiO2) and activated carbon (Pd/AC). Cyclic voltammetry characterization was conducted with respect to saturated calomel electrode (SCE) in an alkaline methanol solution, and the results indicate that the specific activity of Pd/TiO2-C is 2.2 times that of Pd/AC and 1.5 times that of Pd/TiO2. Chronoamperometry results revealed that the TiO2-C support was comparable in stability to activated carbon, but possesses an enhanced current density for methanol oxidation at a potential of −0.2 V vs. SCE. The current study demonstrates the potential of Pd nanoparticle loaded on hierarchical TiO2-C nanobelts for electrocatalytic applications such as fuel cells and batteries.
One Step Quick Detection of Cancer Cell Surface Marker by Integrated NiFe-based Magnetic Biosensing Cell Cultural Chip
Authors: Bao Chenchen , Chen Lei , Wang Tao , Lei Chong , Tian Furong , Cui Daxiang , Zhou Yong
Published: October 2014

RGD peptides has been used to detect cell surface integrin and direct clinical effective therapeutic drug selection. Herein we report that a quick one step detection of cell surface marker that was realized by a specially designed NiFe-based magnetic biosensing cell chip combined with functionalized magnetic nanoparticles. Magnetic nanoparticles with 20-30 nm in diameter were prepared by coprecipitation and modified with RGD-4C, and the resultant RGD-functionalized magnetic nanoparticles were used for targeting cancer cells cultured on the NiFe-based magnetic biosensing chip and distinguish the amount of cell surface receptor-integrin. Cell lines such as Calu3, Hela, A549, CaFbr, HEK293 and HUVEC exhibiting different integrin expression were chosen as test samples. Calu3, Hela, HEK293 and HUVEC cells were successfully identified. This approach has advantages in the qualitative screening test. Compared with traditional method, it is fast, sensitive, low cost, easy-operative, and needs very little human intervention. The novel method has great potential in applications such as fast clinical cell surface marker detection, and diagnosis of early cancer, and can be easily extended to other biomedical applications based on molecular recognition.
Structure and Magnetic Properties of Monodisperse Fe3+-doped CeO2 Nanospheres
Authors: Phokha Sumalin , Pinitsoontorn Supree , Maensiri Santi
Published: October 2014

This work reports the study concerning the structure and magnetic properties of undoped CeO2 and Fe-doped CeO2 (Ce1−x
Fe
x
O2, 0.01 ≤ x ≤ 0.07) nanospheres with diameters of 100∼200 nm prepared by hydrothermal method using polyvinylpyrrolidone (PVP) as surfactant. The prepared samples were studied by using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray absorption near-edge structure (XANES), and vibrating sample magnetometry (VSM). The XRD results showed that Fe-doped CeO2 was single-phased with a cubic structure, and with Fe3+ successfully substituting in Ce4+ sites. Raman spectra showed a redshift of F2g
mode that caused by the Fe doping. The samples of both undoped CeO2 and Fe-doped CeO2 exhibited room temperature ferromagnetism, and the saturated magnetization (M

s
) increased with increasing Fe content until x = 0.05, and then the samples displayed ferromagnetic loops as well as paramagnetic behavior. The roles of Ce3+ and Fe3+ spin electrons are discussed for the ferromagnetism in the Fe-doped CeO2.
Hierarchical Semiconductor Oxide Photocatalyst: A Case of the SnO2 Microflower
Authors: Liu Yang , Jiao Yang , Yin Bosi , Zhang Siwen , Qu Fengyu , Wu Xiang
Published: October 2014

Hierarchically assembled SnO2 microflowers were synthesized by a facile hydrothermal process. Field emission scanning electron microscope results showed these hierarchical nanostructures were built from two dimensional nanosheets with the thicknesses of about 50 nm. Photoluminescence spectrum of the as-obtained products demonstrated a strong visual emission peak at 564 nm. The photochemical measurement results indicated that the as-prepared sample exhibits excellent photocatalytic performance. These three dimensional SnO2 hierarchical nanostructures may have potential applications in waste water purification.