Preparation of nanostructured materials having improved ductility

DOEpatents

Zhao, Yonghao; Zhu, Yuntian T.

2010-04-20

A method for preparing a nanostructured aluminum alloy involves heating an aluminum alloy workpiece at temperature sufficient to produce a single phase coarse grained aluminum alloy, then refining the grain size of the workpiece at a temperature at or below room temperature, and then aging the workpiece to precipitate second phase particles in the nanosized grains of the workpiece that increase the ductility without decreasing the strength of the workpiece.

Uniform β-Co(OH)2 disc-like nanostructures prepared by low-temperature electrochemical rout as an electrode material for supercapacitors

NASA Astrophysics Data System (ADS)

Aghazadeh, Mustafa; Shiri, Hamid Mohammad; Barmi, Abbas-Ali Malek

2013-05-01

Uniform nanostructures of cobalt hydroxide were successfully prepared by a low-temperature electrochemical method via galvanostatically deposition from a 0.005 M Co(NO3)3 bath at 10 °C. The XRD and FT-IR analyses showed that the prepared sample has a single crystalline hexagonal phase of the brucite-like Co(OH)2. Morphological characterization by SEM and TEM revealed that the prepared β-Co(OH)2 was composed of uniform compact disc-like nanostructures with diameters of 40-50 nm. The electrochemical performance of the prepared β-Co(OH)2 was evaluated using cyclic voltammetry and charge-discharge tests. A maximum specific capacitance of 736.5 F g-1 was obtained in aqueous 1 M KOH with the potential range of -0.2-0.5 V (vs. Ag/AgCl) at the scan rate of 10 mV s-1, suggesting the potential application of the prepared nanostructures as an electrode material in electrochemical supercapacitors. The results of this work showed that the low-temperature cathodic electrodeposition method can be recognized as a new and facile route for the synthesis of cobalt hydroxide nanodiscs as a promising candidate for the electrochemical supercapacitors.

Color tuning in neodymium doped dicalcium silicate nanostructures prepared via ultrasound method

NASA Astrophysics Data System (ADS)

Venkataravanappa, M.; Nagabhushana, H.; Basavaraj, R. B.; Venkatachalaiah, K. N.; Prasad, B. Daruka

2017-05-01

Blue light emitting neodymium (Nd) doped dicalcium (Ca2SiO4) silicate nanostructures were prepared for the first time via ultrasound assisted sonochemical synthesis route using cetyltrimethylammonium bromide (CTAB) surfactant. The obtained final product was well characterized. The powder X-ray diffraction (PXRD) profiles confirmed that product was highly crystalline in nature with monoclinic phase. Influence of various reaction parameters such as, the effect of sonication time, concentration of the surfactant and pH of the precursor solution on the morphology was studied in detail. Diffuse reflectance spectroscopy (DRS) was studied to evaluate the band gap energy of the products and the values were found in the range of 5.78 - 6.17 eV. The particle size was estimated by transmission electron microscope (TEM) and it was found in the range of 20-30 nm. Photoluminescence (PL) properties were studied in detail by recording emission spectra of all the Nd doped dicalcium silicate nanostructures at an excitation wavelength of 380 nm. The emission peaks were observed at 469, 520, 545 and 627 nm which corresponds to Nd3+ ion transitions. The 7 mol% Nd3+ doped Ca2SiO4 nanostructures showed maximum intensity. Further photometric measurements were done by evaluating, Commission International De I-Eclairage (CIE) and correlated color temperature (CCT). From CIE it was observed that the color coordinates lies in blue-green region, which slightly shifts to green as the Nd3+ concentration increases. The color purity and quantum efficiency were also estimated and the results indicate that the nanophosphor obtained in this route can be used in preparing light emitting diodes with a blue-green emission as prominent color.

Melt infiltration: an emerging technique for the preparation of novel functional nanostructured materials.

PubMed

de Jongh, Petra E; Eggenhuisen, Tamara M

2013-12-10

The rapidly expanding toolbox for design and preparation is a major driving force for the advances in nanomaterials science and technology. Melt infiltration originates from the field of ceramic nanomaterials and is based on the infiltration of porous matrices with the melt of an active phase or precursor. In recent years, it has become a technique for the preparation of advanced materials: nanocomposites, pore-confined nanoparticles, ordered mesoporous and nanostructured materials. Although certain restrictions apply, mostly related to the melting behavior of the infiltrate and its interaction with the matrix, this review illustrates that it is applicable to a wide range of materials, including metals, polymers, ceramics, and metal hydrides and oxides. Melt infiltration provides an alternative to classical gas-phase and solution-based preparation methods, facilitating in several cases extended control over the nanostructure of the materials. This review starts with a concise discussion on the physical and chemical principles for melt infiltration, and the practical aspects. In the second part of this contribution, specific examples are discussed of nanostructured functional materials with applications in energy storage and conversion, catalysis, and as optical and structural materials and emerging materials with interesting new physical and chemical properties. Melt infiltration is a useful preparation route for material scientists from different fields, and we hope this review may inspire the search and discovery of novel nanostructured materials. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Additive assisted hydrothermal synthesis, characterization and optical properties of one dimensional DyPO4:Ce3+ nanostructures

NASA Astrophysics Data System (ADS)

Khajuria, H.; Kumar, M.; Singh, R.; Ladol, J.; Nawaz Sheikh, H.

2018-05-01

One dimensional nanostructures of cerium doped dysprosium phosphate (DyPO4:Ce3+) were synthesized via hydrothermal route in the presence of different surfactants [sodium dodecyl sulfate (SDS), dodecyl sulfosuccinate (DSS), polyvinyl pyrollidone (PVP)] and solvent [ethylene glycol and water]. The prepared nanostructures were characterized by Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), UV-VIS-NIR absorption spectrophotometer and photoluminescence (PL) studies. The PXRD and FTIR results indicate purity, good crystallinity and effective doping of Ce3+ in nanostructures. SEM and TEM micrographs display nanorods, nanowires and nanobundles like morphology of DyPO4:Ce3+. Energy-dispersive X-ray spectra (EDS) of DyPO4:Ce3+nanostructures confirm the presence of dopant. UV-VIS-NIR absorption spectra of prepared compounds are used to calculate band gap and explore their optical properties. Luminescent properties of DyPO4:Ce3+ was studied by using PL emission spectra. The effect of additives and solvents on the uniformity, morphology and optical properties of the nanostructures were studied in detail.

Preparation and Reactivity of Gasless Nanostructured Energetic Materials

PubMed Central

Manukyan, Khachatur V.; Shuck, Christopher E.; Rogachev, Alexander S.; Mukasyan, Alexander S.

2015-01-01

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites. PMID:25868065

Synthesis, morphology, optical and photocatalytic performance of nanostructured β-Ga{sub 2}O{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Girija, K.; DRDO – BU CLS, Bharathiar University, Coimbatore 641046; Thirumalairajan, S.

2013-06-01

Highlights: ► Nanostructures of β-Ga{sub 2}O{sub 3} were prepared using facile reflux condensation process. ► The pH of the reaction mixture shows evident influence on the size and shape of the nanostructures formed. ► The nanostructures exhibited good photocatalytic activity toward Rhodamine B and was found to be superior for higher pH value. - Abstract: Fine powders of β-Ga{sub 2}O{sub 3} nanostructures were prepared via low temperature reflux condensation method by varying the pH value without using any surfactant. The pH value of reaction mixture had great influence on the morphology of final products. High crystalline single phase β-Ga{sub 2}O{submore » 3} nanostructures were obtained by thermal treatment at 900 °C which was confirmed by X-ray diffraction and Raman spectroscopy. The morphological analysis revealed rod like nanostructures at lower and higher pH values of 6 and 10, while spindle like structures were obtained at pH = 8. The phase purity and presence of vibrational bands were identified using Fourier transform infrared spectroscopy. The optical absorbance spectrum showed intense absorption features in the UV spectral region. A broad blue emission peak centered at 441 nm due to donor–acceptor gallium–oxygen vacancy pair recombination appeared. The photocatalytic activity toward Rhodamine B under visible light irradiation was higher for nanorods at pH 10.« less

Heterojunction Fe2O3-SnO2 Nanostructured Photoanode for Efficient Photoelectrochemical Water Splitting

NASA Astrophysics Data System (ADS)

Han, Hyun Soo; Shin, Sun; Noh, Jun Hong; Cho, In Sun; Hong, Kug Sun

2014-04-01

Hierarchically organized nanostructures were fabricated by growing SnO2 nanoparticles on a fluorine-doped tin oxide/glass substrate via a laser ablation method. Cauliflower-like clusters consisting of agglomerated nanoparticles were deposited and aligned with respect to the substrate with a large internal surface area and open channels of pores. The morphological changes of SnO2 nanostructured films were investigated as a function of the oxygen working pressure in the range of 100-500 mTorr. A nanostructured scaffold prepared at an oxygen working pressure of 100 mTorr exhibited the best photoelectrochemical (PEC) performance. A Ti:Fe2O3-SnO2 nanostructured photoanode showed the photocurrent that was 34% larger than that of a Ti:Fe2O3 flat photoanode when the amount of Ti:Fe2O3 sensitizer was identical for the two photoanodes. The larger surface area and longer electron lifetime of the Ti:Fe2O3-SnO2 nanostructured photoanode explains its improved PEC performance.

Nitrate-assisted photocatalytic efficiency of defective Eu-doped Pr(OH)3 nanostructures.

PubMed

Aškrabić, S; Araújo, V D; Passacantando, M; Bernardi, M I B; Tomić, N; Dojčinović, B; Manojlović, D; Čalija, B; Miletić, M; Dohčević-Mitrović, Z D

2017-12-06

Pr(OH) 3 one-dimensional nanostructures are a less studied member of lanthanide hydroxide nanostructures, which recently demonstrated an excellent adsorption capacity for organic pollutant removal from wastewater. In this study, Pr 1-x Eu x (OH) 3 (x = 0, 0.01, 0.03, and 0.05) defective nanostructures were synthesized by a facile and scalable microwave-assisted hydrothermal method using KOH as an alkaline metal precursor. The phase and surface composition, morphology, vibrational, electronic and optical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, infrared (IR), photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). It was deduced that the incorporation of Eu 3+ ions promoted the formation of oxygen vacancies in the already defective Pr(OH) 3 , subsequently changing the Pr(OH) 3 nanorod morphology. The presence of KNO 3 phase was registered in the Eu-doped samples. The oxygen-deficient Eu-doped Pr(OH) 3 nanostructures displayed an improved photocatalytic activity in the removal of reactive orange (RO16) dye under UV-vis light irradiation. An enhanced photocatalytic activity of the Eu-doped Pr(OH) 3 nanostructures was caused by the synergetic effect of oxygen vacancies and Eu 3+ (NO 3 - ) ions present on the Pr(OH) 3 surface, the charge separation efficiency and the formation of the reactive radicals. In addition, the 3% Eu-doped sample exhibited very good adsorptive properties due to different morphology and higher electrostatic attraction with the anionic dye. Pr 1-x Eu x (OH) 3 nanostructures with the possibility of tuning their adsorption/photocatalytic properties present a great potential for wastewater treatment.

Novel preparation of highly photocatalytically active copper chromite nanostructured material via a simple hydrothermal route

PubMed Central

Beshkar, Farshad; Zinatloo-Ajabshir, Sahar; Bagheri, Samira; Salavati-Niasari, Masoud

2017-01-01

Highly photocatalytically active copper chromite nanostructured material were prepared via a novel simple hydrothermal reaction between [Cu(en)2(H2O)2]Cl2 and [Cr(en)3]Cl3.3H2O at low temperature, without adding any pH regulator or external capping agent. The as-synthesized nanostructured copper chromite was analyzed by transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy, energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Results of the morphological investigation of the as-synthesized products illustrate that the shape and size of the copper chromite depended on the surfactant sort, reaction duration and temperature. Moreover, the photocatalytic behavior of as-obtained copper chromite was evaluated by photodegradation of acid blue 92 (anionic dye) as water pollutant. PMID:28582420

Effect of Eu3+ doping on the structural, morphological and luminescence properties ZnO nanostructures

NASA Astrophysics Data System (ADS)

Vinoditha, U.; Balakrishna, K. M.; Sarojini, B. K.; Narayana, B.; Kumara, K.

2018-05-01

Pure and Eu3+ ions (1, 3, 5 atomic wt%) doped ZnO nanostructures are synthesized by a surfactant assisted hydrothermal method. The effect of doping concentrations on structural, morphological and optical properties of ZnO nanostructures is studied. The XRD analysis shows good crystallinity and the phase purity of the ZnO nanostructures. A shift in the standard Zn-O stretching mode after Eu3+ doping is observed in the FTIR spectra. The images of FESEM demonstrate the morphological variations from hexagonal nanorods to nanoflowers on varying the dopant concentrations. Substitution of Eu3+ ions into Zn2+ sites is confirmed by EDX analysis. The dominance of particle shape over the UV-Visible absorption properties of the prepared samples is noticed. The photoluminescence (PL) emission of undoped and doped ZnO nanostructures show dominant near band edge emission (NBE) in the UV region and minor defect induced deep level emissions in the visible region.

Nano-structured polymer composites and process for preparing same

DOEpatents

Hillmyer, Marc; Chen, Liang

2013-04-16

A process for preparing a polymer composite that includes reacting (a) a multi-functional monomer and (b) a block copolymer comprising (i) a first block and (ii) a second block that includes a functional group capable of reacting with the multi-functional monomer, to form a crosslinked, nano-structured, bi-continuous composite. The composite includes a continuous matrix phase and a second continuous phase comprising the first block of the block copolymer.

3D hierarchical Ag nanostructures formed on poly(acrylic acid) brushes grafted graphene oxide as promising SERS substrates

NASA Astrophysics Data System (ADS)

Xing, Guoke; Wang, Ke; Li, Ping; Wang, Wenqin; Chen, Tao

2018-03-01

In this study, in situ generation of Ag nanostructures with various morphology on poly(acrylic acid) (PAA) brushes grafted onto graphene oxide (GO), for use as substrates for surface-enhanced Raman scattering (SERS), is demonstrated. The overall synthetic strategy involves the loading of Ag precursor ions ((Ag+ and [Ag(NH3)2]+) onto PAA brush-grafted GO, followed by their in situ reduction to Ag nanostructures of various morphology using a reducing agent (NaBH4 or ascorbic acid). Novel 3D hierarchical flowerlike Ag nanostructures were obtained by using AgNO3 as precursor and ascorbic acid as reducing agent. Using 4-aminothiophenol as probe molecules, the as-prepared hierarchical Ag nanostructures exhibited excellent SERS performance, providing enhancement factors of ˜107.

Comparison of the Nanostructure and Mechanical Performance of Highly Exfoliated Epoxy-Clay Nanocomposites Prepared by Three Different Protocols

PubMed Central

Shiravand, Fatemeh; Hutchinson, John M.; Calventus, Yolanda; Ferrando, Francesc

2014-01-01

Three different protocols for the preparation of polymer layered silicate nanocomposites based upon a tri-functional epoxy resin, triglycidyl para-amino phenol (TGAP), have been compared in respect of the cure kinetics, the nanostructure and their mechanical properties. The three preparation procedures involve 2 wt% and 5 wt% of organically modified montmorillonite (MMT), and are: isothermal cure at selected temperatures; pre-conditioning of the resin-clay mixture before isothermal cure; incorporation of an initiator of cationic homopolymerisation, a boron tri-fluoride methyl amine complex, BF3·MEA, within the clay galleries. It was found that features of the cure kinetics and of the nanostructure correlate with the measured impact strength of the cured nanocomposites, which increases as the degree of exfoliation of the MMT is improved. The best protocol for toughening the TGAP/MMT nanocomposites is by the incorporation of 1 wt% BF3·MEA into the clay galleries of nanocomposites containing 2 wt% MMT. PMID:28788672

Solvent-controlled preparation and photocatalytic properties of nanostructured TiO{sub 2} thin films with different morphologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ao, Yanhui, E-mail: andyao@hhu.edu.cn; Gao, Yinyin; Wang, Peifang

2014-01-01

Graphical abstract: Low-temperature growth of nanostructured TiO{sub 2} thin films was presented by a solvent-controlled method. Nanoparticle structured films in anatase phase have been successfully fabricated with some adjustment. The effects of the solvent were investigated and the formation mechanism was proposed. - Highlights: • Nanostructured TiO{sub 2} thin films with different morphologies were obtained at low temperature. • The effects of the solvent on the morphologies of the products were investigated. • The effects of the solvent on the phtocatalytic activity were investigated. - Abstract: A low-temperature growth method of nanostructured TiO{sub 2} thin films with different morphologies wasmore » reported. Rod-like, grass-like and nanosheet structured films have been successfully fabricated just by adjusting the ratio of different solvents. The effects of the solvent on the morphologies of the TiO{sub 2} nanostructures were investigated. The formation mechanism of different morphologies was proposed based on the experiment results. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The photocatalytic activity of as-prepared samples for the degradation of methylene blue (MB) in water was evaluated under UV illumination. Results showed that the solvents exhibited important effect on the morphologies and photocatalytic activity of as-prepared nanostructured titania films.« less

Morphologies, Preparations and Applications of Layered Double Hydroxide Micro-/Nanostructures

PubMed Central

Kuang, Ye; Zhao, Lina; Zhang, Shuai; Zhang, Fazhi; Dong, Mingdong; Xu, Sailong

2010-01-01

Layered double hydroxides (LDHs), also well-known as hydrotalcite-like layered clays, have been widely investigated in the fields of catalysts and catalyst support, anion exchanger, electrical and optical functional materials, flame retardants and nanoadditives. This feature article focuses on the progress in micro-/nanostructured LDHs in terms of morphology, and also on the preparations, applications, and perspectives of the LDHs with different morphologies. PMID:28883378

Structure-Dependent Optical Properties of Self-Organized Bi2Se3 Nanostructures: From Nanocrystals to Nanoflakes.

PubMed

Yang, Shang-Dong; Yang, Liao; Zheng, Yu-Xiang; Zhou, Wen-Jie; Gao, Meng-Yu; Wang, Song-You; Zhang, Rong-Jun; Chen, Liang-Yao

2017-08-30

Bismuth selenide (Bi 2 Se 3 ), with a wide bulk band gap and single massless Dirac cone at the surface, is a promising three-dimensional topological insulator. Bi 2 Se 3 possesses gapless surface states and an insulator-like bulk band gap as a new type of quantum matter. Different Bi 2 Se 3 nanostructures were prepared using electron beam evaporation with high production efficiency. Structural investigations by energy-dispersive X-ray analysis, scanning electron microscopy, and X-ray diffraction revealed the sample stoichiometries and the structural transition mechanism from nanocrystals to nanoflakes. The optical properties systematically probed and analyzed by spectroscopic ellipsometry showed strong dependence on the nanostructures and were also predicted to have structure-modifiable technological prospects. The optical parameters, plasma frequencies, scattering rates of the free electrons, and optical band gaps were related to the topological properties of the Bi 2 Se 3 nanostructures via light-matter interactions, offering new opportunities and approaches for studies on topological insulators and spintronics. The high-quality Bi 2 Se 3 nanostructures provide advantages in exploring novel physics and exploiting prospective applications.

Synthesis and enhanced acetone gas-sensing performance of ZnSnO3/SnO2 hollow urchin nanostructures

NASA Astrophysics Data System (ADS)

Lian, Dandan; Shi, Bing; Dai, Rongrong; Jia, Xiaohua; Wu, Xiangyang

2017-12-01

A kind of novel ZnSnO3/SnO2 hollow urchin nanostructure was synthesized by a facile, eco-friendly two-step liquid-phase process. The structure, morphology, and composition of samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption techniques. The results revealed that many tiny needle-like SnO2 nanowires with the average diameter of 5 nm uniformly grew on the surface of the ZnSnO3 hollow microspheres and the ZnSnO3/SnO2 hollow urchin nanostructures with different SnO2 content also were successfully prepared. In order to comprehend the evolution process of the ZnSnO3/SnO2 hollow urchin nanostructures, the possible growth mechanism of samples was illustrated via several experiments in different reaction conditions. Moreover, the gas-sensing performance of as-prepared samples was investigated. The results showed that ZnSnO3/SnO2 hollow urchin nanostructures with high response to various concentration levels of acetone enhanced selectivity, satisfying repeatability, and good long-term stability for acetone detection. Specially, the 10 wt% ZnSnO3/SnO2 hollow urchin nanostructure exhibited the best gas sensitivity (17.03 for 50 ppm acetone) may be a reliable biomarker for the diabetes patients, which could be ascribed to its large specific surface area, complete pore permeability, and increase of chemisorbed oxygen due to the doping of SnO2.

Nanostructured hybrid hydrogels prepared by a combination of atom transfer radical polymerization and free radical polymerization

PubMed Central

Bencherif, Sidi A.; Siegwart, Daniel J.; Srinivasan, Abiraman; Horkay, Ferenc; Hollinger, Jeffrey O.; Washburn, Newell R.; Matyjaszewski, Krzysztof

2012-01-01

A new method to prepare nanostructured hybrid hydrogels by incorporating well-defined poly(oligo (ethylene oxide) monomethyl ether methacrylate) (POEO300MA) nanogels of sizes 110–120 nm into a larger three-dimensional (3D) matrix was developed for drug delivery scaffolds for tissue engineering applications. Rhodamine B isothiocyanate-labeled dextran (RITC-Dx) or fluorescein isothiocyanate-labeled dextran (FITC-Dx)-loaded POEO300MA nanogels with pendant hydroxyl groups were prepared by activators generated electron transfer atom transfer radical polymerization (AGET ATRP) in cyclohexane inverse miniemulsion. Hydroxyl-containing nanogels were functionalized with methacrylated groups to generate photoreactive nanospheres. 1H NMR spectroscopy confirmed that polymerizable nanogels were successfully incorporated covalently into 3D hyaluronic acid-glycidyl methacrylate (HAGM) hydrogels after free radical photo-polymerization (FRP). The introduction of disulfide moieties into the polymerizable groups resulted in a controlled release of nanogels from cross-linked HAGM hydrogels under a reducing environment. The effect of gel hybridization on the macroscopic properties (swelling and mechanics) was studied. It is shown that swelling and nanogel content are independent of scaffold mechanics. In-vitro assays showed the nanostructured hybrid hydrogels were cytocompatible and the GRGDS (Gly–Arg–Gly–Asp–Ser) contained in the nanogel structure promoted cell–substrate interactions within 4 days of incubation. These nanostructured hydrogels have potential as an artificial extracellular matrix (ECM) impermeable to low molecular weight biomolecules and with controlled pharmaceutical release capability. Moreover, the nanogels can control drug or biomolecule delivery, while hyaluronic acid based-hydrogels can act as a macroscopic scaffold for tissue regeneration and regulator for nanogel release. PMID:19592087

Effect of Fluoride on the Morphology and Electrochemical Property of Co3O4 Nanostructures for Hydrazine Detection

PubMed Central

Gao, Wanlin; Wang, Qiang; Umar, Ahmad

2018-01-01

In this paper, we systematically investigated the influence of fluoride on the morphology and electrochemical property of Co3O4 nanostructures for hydrazine detection. The results showed that with the introduction of NH4F during the synthesis process of Co3O4, both Co(CO3)0.5(OH)·0.11H2O and Co(OH)F precursors would be generated. To understand the influence of F on the morphology and electrochemical property of Co3O4, three Co3O4 nanostructures that were respectively obtained from bare Co(CO3)0.5(OH)·0.11H2O, Co(OH)F and Co(CO3)0.5(OH)·0.11H2O mixtures and bare Co(OH)F were successfully synthesized. The electrochemical tests revealed the sensing performance of prepared Co3O4 nanostructures decreased with the increase in the fluoride contents of precursors. The more that dosages of NH4F were used, the higher crystallinity and smaller specific surface area of Co3O4 was gained. Among these three Co3O4 nanostructures, the Co3O4 that was obtained from bare Co(CO3)0.5(OH)·0.11H2O-based hydrazine sensor displayed the best performances, which exhibited a great sensitivity (32.42 μA·mM−1), a low detection limit (9.7 μΜ), and a wide linear range (0.010–2.380 mM), together with good selectivity, great reproducibility and longtime stability. To the best of our knowledge, it was revealed for the first time that the sensing performance of prepared Co3O4 nanostructures decreased with the increase in fluoride contents of precursors. PMID:29382161

Hydrothermal preparation of silver telluride nanostructures and photo-catalytic investigation in degradation of toxic dyes

NASA Astrophysics Data System (ADS)

Gholamrezaei, Sousan; Salavati-Niasari, Masoud; Ghanbari, Davood; Bagheri, Samira

2016-01-01

Different morphologies of Ag2Te nanostructures were synthesized using TeCl4 as a new precursor and hydrazine hydrate as reducing agent by a hydrothermal method. Various parameters that affect on morphology and purity of nanostructures were optimized. According to our experiments the best time and temperature for preparation of this nanostructure are 12 h and 120 °C. The photo-catalytic behaviour of nanostructures in presence of UV- visible light for degradation of methyl orange was investigated. Results show that the presence of UV light is necessary for an efficient degradation of dye in aqueous solution. On the other hand, as observations propose the Ag2Te reveal a strong photoluminescence peak at room temperature that could be attributed to high level transition in the semiconductor. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) techniques and UV-visible scanning spectrometer (UV-Vis).

A General and Mild Approach to Controllable Preparation of Manganese-Based Micro- and Nanostructured Bars for High Performance Lithium-Ion Batteries.

PubMed

Ma, Guo; Li, Sheng; Zhang, Weixin; Yang, Zeheng; Liu, Shulin; Fan, Xiaoming; Chen, Fei; Tian, Yuan; Zhang, Weibo; Yang, Shihe; Li, Mei

2016-03-07

One-dimensional (1D) micro- and nanostructured electrode materials with controllable phase and composition are appealing materials for use in lithium-ion batteries with high energy and power densities, but they are challenging to prepare. Herein, a novel ethanol-water mediated co-precipitation method by a chimie douce route (synthesis conducted under mild conditions) has been exploited to selectively prepare an extensive series of manganese-based electrode materials, manifesting the considerable generalizability and efficacy of the method. Moreover, by simply tuning the mixed solvent and reagents, transition metal oxide bars with differing aspect ratios and compositions were prepared with an unprecedented uniformity. Application prospects are demonstrated by Li-rich 0.5 Li2 MnO3 ⋅0.5 LiNi1/3 Co1/3 Mn1/3 O2 bars, which demonstrate excellent reversible capacity and rate capability thanks to the steerable nature of the synthesis and material quality. This work opens a new route to 1D micro- and nanostructured materials by customizing the precipitating solvent to orchestrate the crystallization process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of hierarchical β-Ni(OH)2 nanostructures and adsorption characterization of methyl orange dye

NASA Astrophysics Data System (ADS)

Jiao, Shujie; Jin, Yimin; Du, Qian; Zhu, Chunguang; Gao, Shiyong; Wang, Dongbo; Wang, Jinzhong

2018-05-01

The β-Ni(OH)2 nanostructures have been prepared by hydrothermal with ammonia as alkali source. The morphology of β-Ni(OH)2 evolves from hexagon sheets to flower-like hierarchical structure built up from the nanosheets as increasing the amount of ammonia. Hierarchical β-Ni(OH)2 nanostructures have strong adsorption effect on methyl orange dyes. The adsorption mechanism of β-Ni(OH)2 has been investigated, which could be expressed by pseudo-second order kinetic model with best match.

Controllable preparation of flower-like brookite TiO{sub 2} nanostructures via one-step hydrothermal method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou, Yunling; College of Science, Civil Aviation University of China, Tianjin 300300; Tan, Xin

Highlights: • Flower-like brookite TiO{sub 2} structures were prepared by hydrothermal method. • PVP not only acted as a dispersant but also stabilized the layered structure. • The resulted brookite TiO{sub 2} showed high photocatalytic activity under UV irradiation. - Abstract: Flower-like brookite TiO{sub 2} nanostructures were controllable prepared by a one-step hydrothermal method by changing experimental conditions, such as hydrothermal temperature, reaction time and the amount of polyvinylpyrrolidone. The photocatalytic activities of the samples were investigated by degradation of methylene blue (MB) in aqueous solution under UV light irradiation. It was found that the formation of brookite TiO{sub 2}more » nanostructures with various morphologies could be well controlled by the adjustment of hydrothermal temperature, reaction time and the amount of surfactant, and the morphology of the products changed from spindle-like structures to flower-like structures with the increase of hydrothermal temperature, reaction time and the amount of surfactant. The photocatalytic tests indicate that the flower-like brookite TiO{sub 2} nanostructures shows high photocatalytic activity in degradation of methylene blue (MB) under UV light irradiation. The formation mechanism of flower-like brookite TiO{sub 2} nanostructures was also discussed in detail based on the above investigations.« less

3D-nanostructured boron-doped diamond for microelectrode array neural interfacing.

PubMed

Piret, Gaëlle; Hébert, Clément; Mazellier, Jean-Paul; Rousseau, Lionel; Scorsone, Emmanuel; Cottance, Myline; Lissorgues, Gaelle; Heuschkel, Marc O; Picaud, Serge; Bergonzo, Philippe; Yvert, Blaise

2015-06-01

The electrode material is a key element in the design of long-term neural implants and neuroprostheses. To date, the ideal electrode material offering high longevity, biocompatibility, low-noise recording and high stimulation capabilities remains to be found. We show that 3D-nanostructured boron doped diamond (BDD), an innovative material consisting in a chemically stable material with a high aspect ratio structure obtained by encapsulation of a carbon nanotube template within two BDD nanolayers, allows neural cell attachment, survival and neurite extension. Further, we developed arrays of 20-μm-diameter 3D-nanostructured BDD microelectrodes for neural interfacing. These microelectrodes exhibited low impedances and low intrinsic recording noise levels. In particular, they allowed the detection of low amplitude (10-20 μV) local-field potentials, single units and multiunit bursts neural activity in both acute whole embryonic hindbrain-spinal cord preparations and long-term hippocampal cell cultures. Also, cyclic voltammetry measurements showed a wide potential window of about 3 V and a charge storage capacity of 10 mC.cm(-2), showing high potentiality of this material for neural stimulation. These results demonstrate the attractiveness of 3D-nanostructured BDD as a novel material for neural interfacing, with potential applications for the design of biocompatible neural implants for the exploration and rehabilitation of the nervous system. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Lipid nanostructured Hydrogels for Topical Delivery of Anti-inflammatory Drugs: Preparation and Characterization

NASA Astrophysics Data System (ADS)

Acevedo-Robles, Noelia

Diclofenac sodium is a nonsteroidal anti-inflammatory drugs (NSAID) used to treat sign or symptoms of osteoarthritis and rheumatoid arthritis. However, its clinical usage is limited to some extent due to its toxicity and systemic side effects, including gastrointestinal lesions. The development of lipid nanostructured hydrogel for topical application will solve the problems of first pass metabolism minimize systemic side effect of the anti-inflammatory drugs. Two types of nanotechnologies were used: Lipid Nanostructured Lipid carrier (NLC) and Solid Lipid Nanoparticles (SLN). The difference between both nanotechnologies is that NLC carrier contain liquid and solid lipid, however, the SLN contains solid lipid. Both nanostructured lipid carrier is prepared by high pressure micro-fluidizer technology avoiding solvents use. The use of liquid lipid with solid lipid leads us to imperfection in the matrix which can provide more space for the accommodation of the drug, therefore NLC is the more efficient formulation in drug entrapment.

Enhanced photoluminescence of Alq3 via patterned array silver dendritic nanostructures

NASA Astrophysics Data System (ADS)

Hsu, Wei-Hsiu; Hsieh, Ming-Hao; Lo, Shih-Shou

2012-04-01

Various silver nanostructures, semi-ball, jungle, and dendritic, are demonstrated by an electrical deposition process. The formation of silver nanostructures with various morphologies is studied by the mechanism of the diffusion limited aggregation (DLA) model. A array pattern of silver nanostructures can be obtained when the conductive substrate was used in a uniform electrical filed. A thickness 500 nm of Alq3 thin-film was covered on the silver nanostructure by thermal evaporation method. The strongest intensity of Alq3 green emission was observed when the pattern-array dendritic silver nanostructure was covered by Alq3. It can be explained with the plasmonic coupling due to the Alq3 and dendritic nanostructure. The result can help us to further application the patterned-array silver dendritic nanostructure for advanced opto-electronic device.

On the possibility of room temperature ferromagnetism on chunk-shape BaSnO3/ZnO core/shell nanostructures

NASA Astrophysics Data System (ADS)

Rajamanickam, N.; Jayakumar, K.; Ramachandran, K.

2018-04-01

Core/shell BaSnO3/ZnO (BS-ZO) nanostructures were prepared by oxalate precipitation method and wet-chemical method. BaSnO3 (BSO) cubic perovskite structure and ZnO hexagonal wurtzite structure were confirmed by X-ray diffraction (XRD). The crystallite sizes is 23 nm, 29 nm and 27 nm for BSO, ZnO and BS-ZO, respectively. Chunk-shape and cuboids morphology observed from scanning electron microscopy (SEM) analysis. The magnetic properties were studied by VSM for bare and core-shell nano systems and the room temperature ferromagnetism observed for core-shell nanostructures. The BSO/ZnO shows enhanced coercivity and saturated magnetization as compared with BSO and ZnO nanostructures.

Morphology-controllable synthesis of cobalt oxalates and their conversion to mesoporous Co3O4 nanostructures for application in supercapacitors.

PubMed

Wang, Dewei; Wang, Qihua; Wang, Tingmei

2011-07-18

In this work, one-dimensional and layered parallel folding of cobalt oxalate nanostructures have been selectively prepared by a one-step, template-free, water-controlled precipitation approach by simply altering the solvents used at ambient temperature and pressure. Encouragingly, the feeding order of solutions played an extraordinary role in the synthesis of nanorods and nanowires. After calcination in air, the as-prepared cobalt oxalate nanostructures were converted to mesoporous Co(3)O(4) nanostructures while their original frame structures were well maintained. The phase composition, morphology, and structure of the as-obtained products were studied in detail. Electrochemical properties of the Co(3)O(4) electrodes were carried out using cyclic voltammetry (CV) and galvanostatic charge-discharge measurements by a three-electrode system. The electrochemical experiments revealed that the layered parallel folding structure of mesoporous Co(3)O(4) exhibited higher capacitance compared to that of the nanorods and nanowires. A maximum specific capacitance of 202.5 F g (-1) has been obtained in 2 M KOH aqueous electrolyte at a current density of 1 A g(-1) with a voltage window from 0 to 0.40 V. Furthermore, the specific capacitance decay after 1000 continuous charge-discharge cycles was negligible, revealing the excellent stability of the electrode. These characteristics indicate that the mesoporous Co(3)O(4) nanostructures are promising electrode materials for supercapacitors.

Investigation of Ag-TiO2 nanostructures photocatalytic properties prepared by modified dip coating method

NASA Astrophysics Data System (ADS)

AlArfaj, Esam

2016-05-01

In this article, titanium dioxide and silver nanostructures were deposited on glass substrates using modified sol-gel methods and dip-coating technique. The films were characterised chemically and physically using different techniques (TLC, UV-Vis and XRD) and tested for environmental applications regarding degradation of aromatic hydrocarbons. The photocatalytic activity of the TiO2 nanostructures is tested with different small concentrations of phenol in water and reaction mechanisms discussed. Considerable enhancement is observed in the photodegradation activity of Ag-modified (3 wt.%) TiO2 compared to unmodified TiO2 nanostructures for phenol concentrations within the pseudo-first-order Langmuir-Hinshelwood (LH) model for reaction kinetics. The pseudo-first-order global degradation rate constant increased from <0.005 min-1 for TiO2 to 0.013 min-1 for 3 mol% Ag-modified TiO2. The enhancement is attributed to the incorporation of Ag which promotes the generation of reactive oxygen species and increases the carrier recombination life-time. In addition, Ag has been observed to extend the absorption to the visible region by its surface plasmon resonances and to suppress the anatase-rutile phase transformation. Moreover, TiO2 grain size prepared was found to be 10 nm which maximises the active surface area. For phenol initial concentrations as low as 0.0002 M, saturation trend in the degradation process occurred at 0.00014 M and the reaction rate can be fitted with half-order LH kinetics.

Electrical Characteristics and Preparation of Nanostructured Pb(Zr0.5Ti0.5)O3 Films by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Koo, Horng-Show; Chen, Mi; Hotta, Yoichi; Kawai, Tomoji

2007-07-01

Nanostructured thin films of Pb(Zr0.5Ti0.5)O3 on Pt (1000 Å)/Ti (100 Å)/SiO2 (2000 Å)/Si substrates are prepared by spray pyrolysis and subsequently rapid thermal annealing. Lead nitrate, zirconium nitrate and titanium isopropoxide are used as starting material with ethylene glycol as solvent. The crystal structure of the as-sprayed films are transformed from the amorphous, pyrochlore and multiple phases of pyrochlore and perovskite to the single phase of perovskite as the annealing temperature is increased up to 500 °C. For the formation of single phase perovskite, excess lead of 10 mol % is required to compensate the loss of lead during the processing of the primitive films. The physical characteristics of the resultant films show the dielectric constant (\\varepsilonr) of 400, remanent polarization (2Pr) of 30.0 μC/cm2 and coercive field (2Ec) of 70.0 kV/cm, respectively.

Preparation of Salicylic Acid Loaded Nanostructured Lipid Carriers Using Box-Behnken Design: Optimization, Characterization and Physicochemical Stability.

PubMed

Pantub, Ketrawee; Wongtrakul, Paveena; Janwitayanuchit, Wicharn

2017-01-01

Nanostructured lipid carriers loaded salicylic acid (NLCs-SA) were developed and optimized by using the design of experiment (DOE). Box-Behnken experimental design of 3-factor, 3-level was applied for optimization of nanostructured lipid carriers prepared by emulsification method. The independent variables were total lipid concentration (X 1 ), stearic acid to Lexol ® GT-865 ratio (X 2 ) and Tween ® 80 concentration (X 3 ) while the particle size was a dependent variable (Y). Box-Behnken design could create 15 runs by setting response optimizer as minimum particle size. The optimized formulation consists of 10% of total lipid, a mixture of stearic acid and capric/caprylic triglyceride at a 4:1 ratio, and 25% of Tween ® 80 which the formulation was applied in order to prepare in both loaded and unloaded salicylic acid. After preparation for 24 hours, the particle size of loaded and unloaded salicylic acid was 189.62±1.82 nm and 369.00±3.37 nm, respectively. Response surface analysis revealed that the amount of total lipid is a main factor which could affect the particle size of lipid carriers. In addition, the stability studies showed a significant change in particle size by time. Compared to unloaded nanoparticles, the addition of salicylic acid into the particles resulted in physically stable dispersion. After 30 days, sedimentation of unloaded lipid carriers was clearly observed. Absolute values of zeta potential of both systems were in the range of 3 to 18 mV since non-ionic surfactant, Tween ® 80, providing steric barrier was used. Differential thermograms indicated a shift of endothermic peak from 55°C for α-crystal form in freshly prepared samples to 60°C for β´-crystal form in storage samples. It was found that the presence of capric/caprylic triglyceride oil could enhance encapsulation efficiency up to 80% and facilitate stability of the particles.

Facile preparation of SERS and catalytically active Au nanostructures using furfuryl derivatives

NASA Astrophysics Data System (ADS)

Kim, Ki-Jung; Kim, Hyun-Chul; Park, Minsun; Huh, Seong

2017-08-01

Six different types of Au nanostructures with rough surfaces were readily prepared through the redox reactions between Au precursor, AuCl4-, and furfuryl derivatives without extra metal surface capping ligands, in deionized water at room temperature. Furfuryl alcohol (FA) or furfurylamine (FFA) was used as a sole reducing agent for the reduction of Au precursor. Both FA and FFA effectively polymerized during the redox reactions to form polyfuran polymers. These polymers are thought to act as surface capping ligands during the formation of Au nanostructures. Experiments were conducted with three different concentrations of each furfuryl derivative. Interestingly, Au particles prepared from the reaction with varying concentration of FA or FFA showed large differences in size, and revealed that the higher the ratios of [FA]/[AuCl4-] or [FFA]/[AuCl4-], the smaller the size of Au particles. The size of Au particles was in the range of 1 μm to under 30 nm. Among these samples, two nanostructured Au particles, AuFA-4 and AuFFA-1, deposited on a Si wafer by a simple drop-casting method, were revealed as highly active surface-enhanced Raman scattering (SERS) substrates for the detection of methylene blue (MB) and crystal violet (CV). High SERS enhancement factors (EFs) of 106 ∼ 108 for MB and CV were observed. Small size Au nanoparticles (AuFFA-2 and AuFFA-4) were also found to be very active for the catalytic hydrogenation of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 at room temperature. AuFFA-2 could be recycled eight times, without losing its activity.

The Physics and Applications of a 3D Plasmonic Nanostructure

NASA Astrophysics Data System (ADS)

Terranova, Brandon B.

In this work, the dynamics of electromagnetic field interactions with free electrons in a 3D metallic nanostructure is evaluated theoretically. This dissertation starts by reviewing the relevant fundamentals of plasmonics and modern applications of plasmonic systems. Then, motivated by the need to have a simpler way of understanding the surface charge dynamics on complex plasmonic nanostructures, a new plasmon hybridization tree method is introduced. This method provides the plasmonicist with an intuitive way to determine the response of free electrons to incident light in complex nanostructures within the electrostatic regime. Next, a novel 3D plasmonic nanostructure utilizing reflective plasmonic coupling is designed to perform biosensing and plasmonic tweezing applications. By applying analytical and numerical methods, the effectiveness of this nanostructure at performing these applications is determined from the plasmonic response of the nanostructure to an excitation beam of coherent light. During this analysis, it was discovered that under certain conditions, this 3D nanostructure exhibits a plasmonic Fano resonance resulting from the interference of an in-plane dark mode and an out-of-plane bright mode. In evaluating this nanostructure for sensing changes in the local dielectric environment, a figure of merit of 68 is calculated, which is competitive with current localized surface plasmon resonance refractometric sensors. By evaluating the Maxwell stress tensor on a test particle in the vicinity of the nanostructure, it was found that under the right conditions, this plasmonic nanostructure design is capable of imparting forces greater than 10.5 nN on dielectric objects of nanoscale dimensions. The results obtained in these studies provides new routes to the design and engineering of 3D plasmonic nanostructures and Fano resonances in these systems. In addition, the nanostructure presented in this work and the design principles it utilizes have shown

Nanostructured ZnO films with various morphologies prepared by ultrasonic spray pyrolysis and its growing process

NASA Astrophysics Data System (ADS)

Ma, H. L.; Liu, Z. W.; Zeng, D. C.; Zhong, M. L.; Yu, H. Y.; Mikmekova, E.

2013-10-01

Nanostructured ZnO films were prepared by the ultrasonic spray pyrolysis method using Zn(CH3COO)2·2H2O as a precursor. The effects of substrate temperature (Ts) on the morphology and properties were systematically studied. As the Ts increased from 430 °C to 610 °C, the morphology of the film transforms from closed packed nanosheets to dense nanocrystalline film and then to hexagonal nanorod array. The dense film formed at a temperature of 550 °C has the lowest electric resistivity and highest carrier concentration. The optical transmittance for all prepared samples was higher than 90%. The photoluminescence (PL) properties varied with the Ts due to the internal defect difference. The growth mechanism of ZnO film involves island growth and diffusion, which was evident by observing the samples prepared at various times.

Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials

PubMed Central

Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong; Mølhave, Kristian; Liu, Yanguo; Zhao, Yanyan; Wang, Xun; Xu, Shengming; Zhu, Jing

2016-01-01

We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries, the as-prepared Co3O4 hierarchical electrodes delivered high lithium storage properties comparing to the other Co3O4 nanostructures, including a high reversible capacity of 1053.1 mAhg−1 after 50 cycles at a current density of 0.2 C (1 C = 890 mAg−1), good cycling stability and rate capability. PMID:26846434

Binary lipids-based nanostructured lipid carriers for improved oral bioavailability of silymarin.

PubMed

Shangguan, Mingzhu; Lu, Yi; Qi, Jianping; Han, Jin; Tian, Zhiqiang; Xie, Yunchang; Hu, Fuqiang; Yuan, Hailong; Wu, Wei

2014-02-01

The main purpose of this study was to prepare binary lipids-based nanostructured lipid carriers to improve the oral bioavailability of silymarin, a poorly water-soluble liver protectant. Silymarin-loaded nanostructured lipid carriers were prepared by the method of high-pressure homogenization with glycerol distearates (Precirol ATO-5) and oleic acid as the solid and liquid lipids, respectively, and lecithin (Lipoid E 100) and Tween-80 as the emulsifiers. The silymarin-nanostructured lipid carrier prepared under optimum conditions was spherical in shape with mean particle size of ∼78.87 nm, entrapment efficiency of 87.55%, loading capacity of 8.32%, and zeta potential of -65.3 mV, respectively. In vitro release of silymarin-nanostructured lipid carriers was very limited even after 12 h, while in vitro lipolysis showed fast digestion of nanostructured lipid carriers within 1 h. Relative oral bioavailability of silymarin-nanostructured lipid carriers in Beagle dogs was 2.54- and 3.10-fold that of marketed Legalon® and silymarin solid dispersion pellets, respectively. It was concluded that nanostructured lipid carriers were potential drug delivery systems to improve the bioavailability of silymarin. Other than improved dissolution, alternative mechanisms such as facilitated absorption as well as lymphatic transport may contribute to bioavailability enhancement.

Ammonia Vapor-Assisted Synthesis of Cu(OH)2 and CuO Nanostructures: Anionic (Cl-, NO3 -, SO4 2-) Influence on the Product Morphology

NASA Astrophysics Data System (ADS)

Mansournia, Mohammadreza; Arbabi, Akram

2017-01-01

Shape control of inorganic nanostructures generally requires using surfactants or ligands to passivate certain crystallographic planes. This paper describes a novel additive-free synthesis of cupric oxide nanostructures with different morphologies from the aqueous solutions of copper(II) with Cl-, NO3 -, and SO4 2- as counter ions. Through a one-step approach, CuO nanoleaves, nanoparticles and flower-like microspheres were directly synthesized at 80°C upon exposure to ammonia vapor using a cupric solution as a single precursor. Furthermore, during a two-step process, Cu(OH)2 nanofibers and nanorods were prepared under an ammonia atmosphere, then converted to CuO nanostructures with morphology preservation by heat treatment in air. The as-prepared Cu(OH)2 and CuO nanostructures are characterized using x-ray diffraction, scanning electron microscopy and Fourier transformation infrared spectroscopy techniques.

Preparation and characterization of Fe50Co50 nanostructured alloy

NASA Astrophysics Data System (ADS)

Yepes, N.; Orozco, J.; Caamaño, Z.; Mass, J.; Pérez, G.

2014-04-01

Nanostructured Fe50Co50 alloy was prepared by mechanical alloying of Fe and Co powders in a planetary high energy ball milling. The microstructure and structural evolution of the alloy have been investigated as a function of milling time (0 h, 8 h, 20 h and 35 h) by scanning electron microscopy (SEM) and X-Ray diffraction (XRD) characterization techniques. SEM micrographs showed different powder particles morphologies during the mechanical alloying stages. By XRD analysis it could be identified the structural phases of the alloy and the crystallite size was calculated as a function of the milling time.

Synthesis and characterization of nanostructured CaSiO3 biomaterial

NASA Astrophysics Data System (ADS)

Jagadale, Pramod N.; Kulal, Shivaji R.; Joshi, Meghanath G.; Jagtap, Pramod P.; Khetre, Sanjay M.; Bamane, Sambhaji R.

2013-04-01

Here we report a successful preparation of nanostructured calcium silicate by wet chemical approach. The synthesized sample was characterized by various physico-chemical methods. Thermal stability was investigated using thermo-gravimetric and differential thermal analysis (TG-DTA). Structural characterization of the sample was carried out by the X-ray diffraction technique (XRD) which confirmed its single phase hexagonal structure. Transmission electron microscopy (TEM) was used to study the nanostructure of the ceramics while homogeneous grain distribution was revealed by scanning electron microscopy studies (SEM). The elemental analysis data obtained from energy dispersive X-ray spectroscopy (EDAX) were in close agreement with the starting composition used for the synthesis. Superhydrophilic nature of CaSiO3 was investigated at room temperature by sessile drop technique. Effect of porous nanosized CaSiO3 on early adhesion and proliferation of human bone marrow mesenchymal stem cells (BMMSCs) and cord blood mesenchymal stem (CBMSCs) cells was measured in vitro. MTT cytotoxicity test and cell adhesion test showed that the material had good biocompatibility and promoted cell viability and cell proliferation. It has been stated that the cell viability and proliferation are significantly affected by time and concentration of CaSiO3. These findings indicate that the CaSiO3 ceramics has good biocompatibility and that it is promising as a biomaterial.

Preparation and Characterization of Minoxidil Loaded Nanostructured Lipid Carriers.

PubMed

Wang, Wenxi; Chen, Lina; Huang, Xinyan; Shao, Anna

2017-02-01

Nanostructured lipid carriers (NLCs) are interesting delivery systems for enhancing the penetration of an active substance through the skin after topical administration. The present paper described the development of a novel NLCs for minoxidil (MXD) topical delivery. Stearic acid and oleic acid that showed the highest solubility for MXD were selected as solid lipid and liquid lipid, respectively, and the NLCs were prepared by hot high pressure homogenization method. The minoxidil loaded NLCs prepared accordingly to the optimal formulation exhibited spherical shape with a mean diameter of 281.4 ± 7.4 nm, polydispersity of 0.207 ± 0.009, zeta potential of -32.90 ± 1.23 mV, drug entrapment efficiency of 92.48 ± 0.31%, and drug loading of 13.85 ± 0.47%. Storage stability studies demonstrated that the particle size and entrapment efficiency of the MXD-NLCs were not changed during 3 months both at 4°C and room temperature. Moreover, the release of MXD from the NLCs was faster than drug release from SLNs. In vitro skin permeability test demonstrated that MXD-NLCs had a more pronounced permeation and retention profile than MXD-SLNs. Furthermore, no erythema was observed after administration of MXD-NLCs. All these results indicated that the developed MXD-NLCs could be a promising and effective nanocarrier for topical delivery of MXD.

Passivation properties of alumina for multicrystalline silicon nanostructure prepared by spin-coating method

NASA Astrophysics Data System (ADS)

Jiang, Ye; Shen, Honglie; Yang, Wangyang; Zheng, Chaofan; Tang, Quntao; Yao, Hanyu; Raza, Adil; Li, Yufang; Huang, Chunlai

2018-02-01

In this paper, we report passivation properties of inverted pyramidal nanostructure based multi-crystalline silicon (mc-Si) by Al2O3 films with spin-coating method. Precursors AlCl3 and Al(acac)3 for Al2O3 films were chosen for comparison. Al2O3/SiO x stacks were found to be able to passivate the nanostructured surface well. With the number of spin-coating up to five, the Al2O3 films could conformally attach the nanostructure. The weighted average reflectance values (ranging from 400-900 nm) of the passivated silicon surface could be reduced to 10.74% (AlCl3) and 11.12% (Al(acac)3), and the effective carrier lifetime could reach 7.84 and 16.98 μs, respectively. This work presented a potential process to fabricate low cost high efficiency mc-Si solar cells.

3D nanostructured N-doped TiO2 photocatalysts with enhanced visible absorption.

PubMed

Cho, Sumin; Ahn, Changui; Park, Junyong; Jeon, Seokwoo

2018-05-24

Considering the environmental issues, it is essential to develop highly efficient and recyclable photocatalysts in purification systems. Conventional TiO2 nanoparticles have strong intrinsic oxidizing power and high surface area, but are difficult to collect after use and rarely absorb visible light, resulting in low photocatalytic efficiency under sunlight. Here we develop a new type of highly efficient and recyclable photocatalyst made of a three-dimensional (3D) nanostructured N-doped TiO2 monolith with enhanced visible light absorption. To prepare the sample, an ultrathin TiN layer (∼10 nm) was conformally coated using atomic layer deposition (ALD) on 3D nanostructured TiO2. Subsequent thermal annealing at low temperature (550 °C) converted TiN to anatase phase N-doped TiO2. The resulting 3D N-doped TiO2 showed ∼33% enhanced photocatalytic performance compared to pure 3D TiO2 of equivalent thickness under sunlight due to the reduced bandgap, from 3.2 eV to 2.75 eV through N-doping. The 3D N-doped TiO2 monolith could be easily collected and reused at least 5 times without any degradation in photocatalytic performance.

Flexible fabrication of multi-scale integrated 3D periodic nanostructures with phase mask

NASA Astrophysics Data System (ADS)

Yuan, Liang Leon

designed with isotropic properties attractive for generating a complete photonic band gap (PBG). An isolation layer was used between adjacent polymer layers to offer a reversal coating for sample preparation of scanning electron microscopy (SEM) imaging and top surface planarization. Electron beam lithography has been employed to fabricate a multi-level nano-grating phase mask that produces a diamond-like 3D nanostructure via phase mask lithography, promising for creating photonic crystal (PC) templates that can be inverted with high-index materials and form a complete PBG at telecommunication wavelengths. A laser scanning holographic method for 3D exposure in thick photoresist is introduced that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form highly uniform 3D nanostructure with beam size scaled to small 200 microm diameter. Further direct-write holography demonstrates monolithical writing of multi-scale lab-on-a-chip with multiple functionalities including on-chip integrated fluorescence. Various 3D periodic nanostructures are demonstrated over a 15 mmx15 mm area, through full 40 microm photoresist thickness and with uniform structural and optical properties revealed by focused ion beam (FIB) milling, SEM imaging and stopband measures. The lateral and axial periods scale from respective 1500 nm to 570 nm and 9.2 microm to 1.2 microm to offer a Gamma-Z stopband at 1.5 microm. Overall, laser scanning is presented as a facile means to embed 3D PC nanostructure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

Well-ordered large-area arrays of epitaxial ferroelectric (Bi,La)4Ti3O12 nanostructures fabricated by gold nanotube-membrane lithography

NASA Astrophysics Data System (ADS)

Lee, Sung Kyun; Lee, Woo; Alexe, Marin; Nielsch, Kornelius; Hesse, Dietrich; Gösele, Ulrich

2005-04-01

Two-dimensionally well-ordered, large-area arrays of epitaxial, ferroelectric, La-substituted Bi4Ti3O12 (BLT) nanostructures are prepared using gold nanotube membranes as a liftoff mask. Epitaxial nanostructures with a height of about 65nm and a lateral size of about 150nm, with either (001) ("c-axis") orientation, or mixed (118)/(100) ("non-c-axis") orientation, are obtained on (001)- and (011)-oriented SrTiO3 substrates, respectively. The ferroelectric properties are probed by piezoresponse scanning force microscopy. Non-c-axis-oriented BLT nanostructures show an effective piezoresponse coefficient (2dzz) of about 38.0pm /V, whereas c-axis-oriented structures show one of only about 4.9pm/V.

Effects of surface morphology of ZnO seed layers on growth of ZnO nanostructures prepared by hydrothermal method and annealing.

PubMed

Yim, Kwang Gug; Kim, Min Su; Leem, Jae-Young

2013-05-01

ZnO nanostructures were grown on Si (111) substrates by a hydrothermal method. Prior to growing the ZnO nanostructures, ZnO seed layers with different post-heat temperatures were prepared by a spin-coating process. Then, the ZnO nanostructures were annealed at 500 degrees C for 20 min under an Ar atmosphere. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) were carried out at room temperature (RT) to investigate the structural and optical properties of the as-grown and annealed ZnO nanostructures. The surface morphologies of the seed layers changed from a smooth surface to a mountain chain-like structure as the post-heating temperatures increased. The as-grown and annealed ZnO nanostructures exhibited a strong (002) diffraction peak. Compared to the as-grown ZnO nanostructures, the annealed ZnO nanostructures exhibited significantly strong enhancement in the PL intensity ratio by almost a factor of 2.

Large-scale synthesis of a novel tri(8-hydroxyquioline) aluminum nanostructure.

PubMed

Tian, Xike; Fei, Jinbo; Pi, Zhenbang; Yang, Chao; Xiao, Zhidong; Zhang, Lide

2006-08-01

A novel tri(8-hydroxyquioline) aluminum (AlQ3) nanostructure was prepared on large scale at low cost by low-temperature physical vapor deposition (PVD). The morphologies, the chemical bondings, and photoluminescence of the AlQ3 nanostructure were investigated by environmental scanning electronic microscopy (ESEM), Fourier transform infrared spectrum (FT-IR), and photoluminescence (PL) spectra, respectively. The AlQ3 nanostructure was composed of micro-sphere with nanowire-cluster growing on the surface. The diameter of micro-sphere and nanowire were about 5 microm and 80 nm, respectively. FT-IR results indicated that the AlQ3 molecule had a strong thermal stability under research conditions. The growth mechanism of the novel nanostructure was discussed. The novel organic nanostructure would be believed to attractive building field-emission devices and other optical devices.

Optical and structural properties of carbon dots/TiO2 nanostructures prepared via DC arc discharge in liquid

NASA Astrophysics Data System (ADS)

Biazar, Nooshin; Poursalehi, Reza; Delavari, Hamid

2018-01-01

Synthesis and development of visible active catalysts is an important issue in photocatalytic applications of nanomaterials. TiO2 nanostructures coupled with carbon dots demonstrate a considerable photocatalytic activity in visible wavelengths. Extending optical absorption of a wide band gap semiconductor such as TiO2 with carbon dots is the origin of the visible activity of carbon dots modified semiconductor nanostructures. In addition, carbon dots exhibit high photostability, appropriate electron transport and chemical stability without considerable toxicity or environmental footprints. In this study, optical and structural properties of carbon dots/TiO2 nanostructures prepared via (direct current) DC arc discharge in liquid were investigated. Crystal structure, morphology and optical properties of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectroscopy respectively. SEM images show formation of spherical nanoparticles with an average size of 27 nm. In comparison with pristine TiO2, optical transmission spectrum of carbon dots/TiO2 nanostructures demonstrates an absorption edge at longer wavelengths as well a high optical absorption in visible wavelengths which is significant for visible activity of nanostructures as a photocatalyst. Finally, these results can provide a flexible and versatile pathway for synthesis of carbon dots/oxide semiconductor nanostructures with an appropriate activity under visible light.

Fluorescent Zn-PDC/Tb3+ Coordination Polymer Nanostructure: A Candidate for Highly Selective Detections of Cefixime Antibiotic and Acetone in Aqueous System.

PubMed

Pan, Hong; Wang, Sufan; Dao, Xiaoyao; Ni, Yonghong

2018-02-05

Tb 3+ -doped zinc-based coordination polymer nanospindle bundles (Zn-PDC/Tb 3+ , or [Zn(2,5-PDC)(H 2 O) 2 ]·H 2 O/Tb 3+ ) were synthesized by a simple solution precipitation route at room temperature, employing Zn(NO 3 ) 2 , Tb(NO 3 ) 3 , and 2,5-Na 2 PDC as the initial reactants, and a mixture of water and ethanol with the volume ratio of 10:10 as the solvent. The as-obtained nanostructures presented strong fluorescent emission under the excitation of 298 nm light, which was attributed to the characteristic emission of the Tb 3+ ion. It was found that the above-mentioned strong fluorescence of the nanostructures could be selectively quenched by cefixime (CFX) in aqueous solution. The other common antibiotics hardly interfered. Thus, as-obtained Zn-PDC/Tb 3+ nanostructures could be prepared as a highly sensitive fluorescence probe for selective detection of CFX in an aqueous system. The corresponding detection limit reached 72 ppb. The theoretic calculation and UV-vis absorption experiments confirmed that the fluorescence quenching of Zn-PDC/Tb 3+ nanostructures toward CFX should be attributed to the electron transfer and the fluorescence inner filter effect between the fluorescent matter and the analyte. In addition, the strong fluorescence of the nanostructures could also be selectively quenched by acetone in the water system.

Preparation and Characterization of C60/Graphene Hybrid Nanostructures.

PubMed

Chen, Chuanhui; Mills, Adam; Zheng, Husong; Li, Yanlong; Tao, Chenggang

2018-05-15

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We present methods for depositing and passively manipulating C60 molecules on rippled graphene that advance the pursuit of realizing applications involving 1D C60/graphene hybrid structures. The techniques applied in this exposition are geared towards high vacuum systems with preparation areas capable of supporting molecular deposition as well as thermal annealing of the samples. We focus on C60 deposition at low pressure using a homemade Knudsen cell connected to a scanning tunneling microscopy (STM) system. The number of molecules deposited is regulated by controlling the temperature of the Knudsen cell and the deposition time. One-dimensional (1D) C60 chain structures with widths of two to three molecules can be prepared via tuning of the experimental conditions. The surface mobility of the C60 molecules increases with annealing temperature allowing them to move within the periodic potential of the rippled graphene. Using this mechanism, it is possible to control the transition of 1D C60 chain structures to a hexagonal close packed quasi-1D stripe structure.

Morphology-controlled synthesis of α-Fe 2O 3 nanostructures with magnetic property and excellent electrocatalytic activity for H 2O 2

NASA Astrophysics Data System (ADS)

Li, Xiyan; Lei, Yongqian; Li, Xiaona; Song, Shuyan; Wang, Cheng; Zhang, Hongjie

2011-12-01

α-Fe 2O 3 nanocrystals (NCs) with different morphologies are successfully synthesized via a facile template-free hydrothermal route. By simply changing the volume ratio of ethanol to water, we obtained three different α-Fe 2O 3 nanostructures of rhombohedra, truncated rhombohedra and hexagonal sheet. The morphologies and structures of the as-obtained products have been confirmed by varieties of characterizations such as X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The influences of the experimental conditions, such as the amount of NaOH and reaction temperature on the morphologies of the as-prepared α-Fe 2O 3 NCs, have been well investigated. Additionally, magnetic investigations show that the as-obtained α-Fe 2O 3 nanostructures show structure-dependent magnetic properties. Furthermore, the electrochemical experiments indicate that the as-prepared α-Fe 2O 3 hexagonal sheets exhibit strong electrocatalytic reduction activity for H 2O 2.

3D Printed Block Copolymer Nanostructures

ERIC Educational Resources Information Center

Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

2015-01-01

The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

Field emission properties and strong localization effect in conduction mechanism of nanostructured perovskite LaNiO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamble, Ramesh B., E-mail: rbk.physics@coep.ac.in; Department of Physics, College of Engineering, Pune 411005, Maharashtra; Tanty, Narendra

2016-08-22

We report the potential field emission of highly conducting metallic perovskite lanthanum nickelate (LaNiO{sub 3}) from the nanostructured pyramidal and whisker shaped tips as electron emitters. Nano particles of lanthanum nickelate (LNO) were prepared by sol-gel route. Structural and morphological studies have been carried out. Field emission of LNO exhibited high emission current density, J = 3.37 mA/cm{sup 2} at a low threshold electric field, E{sub th} = 16.91 V/μm, obeying Fowler–Nordheim tunneling. The DC electrical resistivity exhibited upturn at 11.6 K indicating localization of electron at low temperature. Magnetoresistance measurement at different temperatures confirmed strong localization in nanostructured LNO obeying Anderson localization effect at low temperature.

Structural and optical properties of nanostructured CdSe thin films prepared by electrochemical deposition

NASA Astrophysics Data System (ADS)

Bai, Rekha; Chaudhary, Sujeet; Pandya, Dinesh K.

2018-05-01

Cadmium selenide (CdSe) nanostructured thin films have been grown on fluorine doped tin oxide (FTO) coated glass substrates by potentiostatic electrochemical deposition (ECD) technique for use in solar energy conversion devices. The effect of bath temperature on the structural, morphological and optical properties of prepared CdSe films has been explored. X-ray diffraction (XRD) and Raman spectroscopy clearly show that the CdSe films are polycrystalline and exhibit phase transformation from wurtzite to zincblende structure with increase in bath temperature. Optical spectra reveal that the nanostructured CdSe films have high absorbance in visible region and the films show a red shift in direct optical energy band gap from 1.90 to 1.65 eV with increase in bath temperature due to change in phase and bandgap tuning related to quantum confinement effect.

One-dimensional fossil-like γ-Fe2O3@carbon nanostructure: preparation, structural characterization and application as adsorbent for fast and selective recovery of gold ions from aqueous solution

NASA Astrophysics Data System (ADS)

Gunawan, Poernomo; Xiao, Wen; Hao Chua, Marcus Wen; Poh-Choo Tan, Cheryl; Ding, Jun; Zhong, Ziyi

2016-10-01

One-dimensional (1D) magnetic nanostructures with high thermal stability have important industrial applications, but their fabrication remains a big challenge. Herein we demonstrate a scalable approach for the preparation of stable 1D γ-Fe2O3@carbon, which is also applicable for other metal oxide-core and carbon-shell nanostructures, such as 1D TiO2@carbon. One-dimensional ferric oxyhydroxide (α-FeO(OH)) was initially prepared by a hydrothermal method, followed by carbon coating through hydrothermal treatment of the resulting metal oxide in glucose solution. After calcination in N2 gas at 500 °C and subsequent exposure to air, the initial carbon-coated 1D α-Fe2O3 was converted to 1D γ-Fe2O3@carbon, which was very stable without any observed changes even after 1.5 years of storage under ambient conditions. The materials were then used as adsorbents and found to be highly selective towards Au (III) adsorption, of which the maximum adsorption capacity is about 600 mg Au/g sorbent (1132 mg Au/g carbon). The spent sorbent containing Au after adsorption can be readily collected by applying a magnetic field due to the presence of the magnetic core, and the adsorbed Au particles are subsequently recovered after the combustion and dissolution of the sorbent. This work demonstrates not only a facile approach to the fabrication of robust 1D magnetic materials with a stable carbon shell, but also a possible cyanide-free process for the fast and selective recovery of gold from electronic waste and industrial water.

Preparation of multifunctional Al-Mg alloy surface with hierarchical micro/nanostructures by selective chemical etching processes

NASA Astrophysics Data System (ADS)

Shi, Tian; Kong, Jianyi; Wang, Xingdong; Li, Xuewu

2016-12-01

A superamphiphobic aluminum magnesium alloy surface with enhanced anticorrosion behavior has been prepared in this work via a simple and low-cost method. By successively polishing, etching and boiling treatments, the multifunctional hierarchical binary structures composed of the labyrinth-like concave-convex microstructures and twisty nanoflakes have been prepared. Results indicate that a superhydrophobic contact angle of 160.5° and superoleophobic contact angle larger than 150° as well as low adhesive property to liquids are achieved after such structures being modified with fluoroalkyl-silane. Furthermore, the anticorrosion behaviors in seawater of as-prepared samples are characterized by electrochemical tests including the impedance spectroscopies, equivalent circuits fittings and polarization curves. It is found that the hierarchical micro/nanostructures accompanying with the modified coating are proved to possess the maximal coating coverage rate of 90.0% larger than microstructures of 85.9%, nanostructures of 83.8% and bare polished surface of 67.1% suggesting the optimal anticorrosion. Finally, a great potential application in concentrators for surface-enhanced Raman scattering (SERS) analysis of toxic and pollutive ions on the superamphiphobic surface is also confirmed. This work has wider significance in extending further applications of alloys in engineering and environmental detecting fields.

3D vertical nanostructures for enhanced infrared plasmonics.

PubMed

Malerba, Mario; Alabastri, Alessandro; Miele, Ermanno; Zilio, Pierfrancesco; Patrini, Maddalena; Bajoni, Daniele; Messina, Gabriele C; Dipalo, Michele; Toma, Andrea; Proietti Zaccaria, Remo; De Angelis, Francesco

2015-11-10

The exploitation of surface plasmon polaritons has been mostly limited to the visible and near infrared range, due to the low frequency limit for coherent plasmon excitation and the reduction of confinement on the metal surface for lower energies. In this work we show that 3D--out of plane--nanostructures can considerably increase the intrinsic quality of the optical output, light confinement and electric field enhancement factors, also in the near and mid-infrared. We suggest that the physical principle relies on the combination of far field and near field interactions between neighboring antennas, promoted by the 3D out-of-plane geometry. We first analyze the changes in the optical behavior, which occur when passing from a single on-plane nanostructure to a 3D out-of-plane configuration. Then we show that by arranging the nanostructures in periodic arrays, 3D architectures can provide, in the mid-IR, a much stronger plasmonic response, compared to that achievable with the use of 2D configurations, leading to higher energy harvesting properties and improved Q-factors, with bright perspective up to the terahertz range.

Novel flame synthesis of nanostructured α-Fe2O3 electrode as high-performance anode for lithium ion batteries

NASA Astrophysics Data System (ADS)

Wang, Yang; Roller, Justin; Maric, Radenka

2018-02-01

Nanostructured electrodes have significant potential for enhancing the kinetics of lithium storage in secondary batteries. A simple and economical manufacturing approach of these electrodes is crucial to the development and application of the next generation lithium ion (Li-ion) batteries. In this study, nanostructured α-Fe2O3 electrode is fabricated by a novel one-step flame combustion synthesis method, namely Reactive Spray Deposition Technology (RSDT). This process possesses the merits of simplicity and low cost. The structure and morphology of the electrode are investigated with X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical performance of the nanostructured α-Fe2O3 electrodes as the anodes for Li-ion batteries is evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy in coin-type half-cells. The as-prepared electrodes demonstrate superior cyclic performance at high current rate, which delivers a high reversible capacity of 1239.2 mAh g-1 at 1 C after 500 cycles. In addition, a discharge capacity of 513.3 mAh g-1 can be achieved at 10 C.

Hybrid ZnPc@TiO2 nanostructures for targeted photodynamic therapy, bioimaging and doxorubicin delivery.

PubMed

Flak, Dorota; Yate, Luis; Nowaczyk, Grzegorz; Jurga, Stefan

2017-09-01

In this study ZnPc@TiO 2 hybrid nanostructures, both nanoparticles and nanotubes, as potential photosensitizers for the photodynamic therapy, fluorescent bioimaging agents, as well as anti-cancer drug nanocarriers, were prepared via zinc phthalocyanine (ZnPc) deposition on TiO 2 . In order to provide the selectivity of prepared hybrid nanostructures towards cancer cells they were modified with folic acid molecules (FA). The efficient attachment of both ZnPc and FA molecules was confirmed with dynamic light scattering (DLS), zeta potential measurements and X-ray photoelectron spectroscopy (XPS). It was presented that ZnPc and FA attachment has a strong effect on fluorescence emission properties of TiO 2 nanostructures, which can be further used for their simultaneous visualization upon cellular uptake. ZnPc@TiO 2 and FA/ZnPc@TiO 2 hybrid nanotubes were then employed as doxorubicin nanocarriers. It was demonstrated that doxorubicin can be easily loaded on these hybrid nanostructures via an electrostatic interaction and then released. In vitro cytotoxicity and photo-cytotoxic activity studies showed that prepared hybrid nanostructures were selectively targeting to cancer cells. Doxorubicin loaded hybrid nanostructures were significantly more cytotoxic than un-loaded ones and their cytotoxic effect was even more severe upon irradiation. The cellular uptake of prepared hybrid nanostructures and their localization in cells was monitored in vitro in 2D cell culture and tumor-like 3D multicellular culture environment with fluorescent confocal microscopy. These hybrid nanostructures preferentially penetrated into human cervical cancer cells (HeLa) than into normal fibroblasts (MSU-1.1) and were mainly localized within the cell cytoplasm. HeLa cells spheroids were also efficiently labelled by prepared hybrid nanostructures. Fluorescent imaging of Hela cells treated with doxorubicin loaded hybrid nanostructures showed that doxorubicin was effectively delivered into cells

Wetting characteristics of 3-dimensional nanostructured fractal surfaces

NASA Astrophysics Data System (ADS)

Davis, Ethan; Liu, Ying; Jiang, Lijia; Lu, Yongfeng; Ndao, Sidy

2017-01-01

This article reports the fabrication and wetting characteristics of 3-dimensional nanostructured fractal surfaces (3DNFS). Three distinct 3DNFS surfaces, namely cubic, Romanesco broccoli, and sphereflake were fabricated using two-photon direct laser writing. Contact angle measurements were performed on the multiscale fractal surfaces to characterize their wetting properties. Average contact angles ranged from 66.8° for the smooth control surface to 0° for one of the fractal surfaces. The change in wetting behavior was attributed to modification of the interfacial surface properties due to the inclusion of 3-dimensional hierarchical fractal nanostructures. However, this behavior does not exactly obey existing surface wetting models in the literature. Potential applications for these types of surfaces in physical and biological sciences are also discussed.

Particle agglomerated 3-d nanostructures for photon absorption

NASA Astrophysics Data System (ADS)

Sivayoganathan, Mugunthan

The main objective of this thesis is to investigate the photon absorption properties of particle agglomerated 3-D structures that are synthesized through femtosecond laser ablation of solids. The size and morphology of these particle agglomerated 3-D structures, which can be tailored through adjusting laser parameters, determine the photon absorption property. A systematic theoretical and experimental study was performed to identify the effect of lasers on the size of the formed particles. The literature survey showed that the amount of supersaturation influences the growth rate as well as the nucleation rate of vapour condensed nanoparticles. Based on this theory, a mechanism was formed to explain the control of laser parameters over the size of formed particles. Further, a theoretical explanation was proposed from the experimental results for the transition of particle size distribution modals. These proposed mechanisms and explanations show the variation in particle size in the particle agglomerated 3-D nanostructures with laser parameters. The effect of laser parameters on the formed ring size was studied. Based on the previous studies, a mechanism was proposed for the formation of ring nanoclusters. The laser pulse intensity dependent ponderomotive force was the key force to define the formation of ring nanoclusters. Then the effect of laser parameters on ring size was studied. Structures fabricated on several materials such as graphite, aluminosilicate ceramic, zinc ingot, gold, and titanium were analyzed to show the influence of material properties, laser parameters, and the environmental conditions on the size of ring formed. The studies performed on the structures showed a minimum absorption of 0.75 A.U. in the bandwidth from UV to IR. The absorption spectrum is much wider compared to existing nanomaterials, such as silicon nanostructures and titanium dioxide nanostructures. To the best of the author's knowledge, it is a very competitive absorption rate

On the application of nanostructured electrodes prepared by Ti/TiO2/WO3 "template": a case study of removing toxicity of indigo using visible irradiation.

PubMed

Guaraldo, Thais T; Zanoni, Thalita B; de Torresi, Susana I C; Gonçales, Vinicius R; Zocolo, Guilherme J; Oliveira, Danielle P; Zanoni, Maria Valnice B

2013-04-01

New assays with HepG2 cells indicate that Indigo Carmine (IC), a dye that is widely used as additive in many food and pharmaceutical industries exhibited cytotoxic effects. This work describes the development of a bicomponent nanostructured Ti/TiO2/WO3 electrode prepared by "template" method and investigates its efficiency in a photoelectrocatalytic method by using visible light irradiation and applied potential of 1V. After 2h of treatment there are reduction of 97% discoloration, 62% of mineralization and formation of three byproducts assigned as: 2-amine-5-sulfo-benzoic acid, 2,3-dioxo-14-indole-5-sulfonic acid, and 2-amino-α-oxo-5-sulfo-benzeneacetic acid were identified by HPLC-MS/MS. But, cytotoxicity was completely removed after 120 min of treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

The performance of hematite nanostructures in different humidity levels

NASA Astrophysics Data System (ADS)

Ahmad, W. R. W.; Mamat, M. H.; Zoolfakar, A. S.; Khusaimi, Z.; Yusof, M. M.; Ismail, A. S.; Saidi, S. A.; Rusop, M.

2018-05-01

In this study, hematite (α-Fe2O3) nanostructure were prepared in Schott vials on fluorine-doped tin oxide (FTO) coated glass substrate using the sonicated immersion method in aqueous solution with ferric chloride FeCl3ṡ6H2O as a precursor and urea NH2-CONH2 as a stabilizer. The samples were characterized for different level of humidity conditions within range 40% to 90% RH. Based on the results obtained, the hematite nanostructure exhibited good optical properties and virtuous sensor response with high sensitivity. The fabricated hematite nanostructure has revealed a good potential for humidity sensor application based on the results obtained under different levels of humidity.

Antimicrobial activity of TiO2 nanostructures synthesized by hydrothermal method

NASA Astrophysics Data System (ADS)

Surah, Shivani Singh; Sirohi, Siddharth; Nain, Ratyakshi; Kumar, Gulshan

2018-02-01

Titania nanostructures were synthesized by hydrothermal method. Titanium tetrachloride was used as a precursor, sodium hydroxide was used as a solvent. Effect on their morphology by variation of parameters like temperature (110°C, 160°C and 180°C), time (15h,18h, 20h, 22h, 24h) and concentration of the solvent NaOH (5M, 8M, 10 M, 12M) were studied. The obtained TiO2 nanostructures were washed with deionized water. The structure, size, morphology of the prepared nanostructures were analyzed by SEM (scanning electron microscope), DLS (dynamic light scattering), TEM (transmission electron microscope). SEM and TEM revealed the shape, size of the nanostructures. DLS reported the particle size of prepared TiO2 nanoparticles. Polymeric films based on polyvinyl alcohol (PVA) doped with titanium dioxide nanostructures at different weight percentage (0.5, 0.75, 1,2 TiO2/PVA) were prepared using the ultra sonication and solution casting techniques. The appropriate weight of PVA was dissolved in deionized water. The mixture was magnetically stirred continuously and heated (80°C) for 4 hours, until the solution mixture becomes homogenous. Different weight percentage of TiO2 nanostructures were added to deionized water and sonicated for 3 hours to prevent the nanostructures agglomeration. The mixture was mixed with the PVA solution and magnetically stirred for 1 hour to get good dispersion without agglomeration. The final PVA /TiO2 mixture were casted in glass Petridish, were left until dry. Ultrasonication was used as a major factor for preparation in order to get better dispersion. Nanocomposite films were characterized using SEM and were found to exhibit antimicrobial properties when treated with E.coli and pseudomonas.

Crystal nuclei templated nanostructured membranes prepared by solvent crystallization and polymer migration

NASA Astrophysics Data System (ADS)

Wang, Bo; Ji, Jing; Li, Kang

2016-09-01

Currently, production of porous polymeric membranes for filtration is predominated by the phase-separation process. However, this method has reached its technological limit, and there have been no significant breakthrough over the last decade. Here we show, using polyvinylidene fluoride as a sample polymer, a new concept of membrane manufacturing by combining oriented green solvent crystallization and polymer migration is able to obtain high performance membranes with pure water permeation flux substantially higher than those with similar pore size prepared by conventional phase-separation processes. The new manufacturing procedure is governed by fewer operating parameters and is, thus, easier to control with reproducible results. Apart from the high water permeation flux, the prepared membranes also show excellent stable flux after fouling and superior mechanical properties of high pressure load and better abrasion resistance. These findings demonstrate the promise of a new concept for green manufacturing nanostructured polymeric membranes with high performances.

Preparation and characterization of photocatalytic carbon dots-sensitized electrospun titania nanostructured fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Haopeng; Zhu, Yihua, E-mail: yhzhu@ecust.edu.cn; Cao, Huimin

2013-02-15

Graphical abstract: Display Omitted Highlights: ► The TiO{sub 2}-CDs nanostructured fibers are fabricated by using APS combining the electrospinning TiO{sub 2} nanostructured fibers and CDs. ► The CD can work as a photosensitizer in the degradation of rhodamine B under visible light irradiation. ► The TiO{sub 2}-CDs nanostructured fibers exhibit enhanced photocatalytic efficiency and can be easily handled and recycled. -- Abstract: The carbon dots (CDs) are new functional carbon-aceous materials. Compared to conventional dye molecules and semiconductor quantum dots, CDs are superior in chemical inertness and low toxicity. The TiO{sub 2}-CDs nanostructured fibers were fabricated by combining the electrospinningmore » technique and reflux method. Compared with the pure TiO{sub 2} nanostructured fibers and P25, the TiO{sub 2}-CDs nanostructured fibers exhibited enhanced photocatalytic efficiency of photodegradation of rhodamine B (RhB) under visible light irradiation. The enhanced photocatalytic activity of TiO{sub 2}-CDs nanostructured fibers could be attributed to the presence of CDs embedded in TiO{sub 2} nanostructured fibers. The CD can work as a photosensitizer in the degradation. Furthermore, the TiO{sub 2}-CDs nanostructured fibers could be easily handled and recycled due to their one-dimensional nanostructural property.« less

Comparison of the Nanostructure and Mechanical Performance of Highly Exfoliated Epoxy-Clay Nanocomposites Prepared by Three Different Protocols.

PubMed

Shiravand, Fatemeh; Hutchinson, John M; Calventus, Yolanda; Ferrando, Francesc

2014-05-30

Three different protocols for the preparation of polymer layered silicate nanocomposites based upon a tri-functional epoxy resin, triglycidyl para -amino phenol (TGAP), have been compared in respect of the cure kinetics, the nanostructure and their mechanical properties. The three preparation procedures involve 2 wt% and 5 wt% of organically modified montmorillonite (MMT), and are: isothermal cure at selected temperatures; pre-conditioning of the resin-clay mixture before isothermal cure; incorporation of an initiator of cationic homopolymerisation, a boron tri-fluoride methyl amine complex, BF₃·MEA, within the clay galleries. It was found that features of the cure kinetics and of the nanostructure correlate with the measured impact strength of the cured nanocomposites, which increases as the degree of exfoliation of the MMT is improved. The best protocol for toughening the TGAP/MMT nanocomposites is by the incorporation of 1 wt% BF₃·MEA into the clay galleries of nanocomposites containing 2 wt% MMT.

3D printing of biomaterials with mussel-inspired nanostructures for tumor therapy and tissue regeneration.

PubMed

Ma, Hongshi; Luo, Jian; Sun, Zhe; Xia, Lunguo; Shi, Mengchao; Liu, Mingyao; Chang, Jiang; Wu, Chengtie

2016-12-01

Primary bone cancer brings patients great sufferings. To deal with the bone defects resulted from cancer surgery, biomaterials with good bone-forming ability are necessary to repair bone defects. Meanwhile, in order to prevent possible tumor recurrence, it is essential that the remaining tumor cells around bone defects are completely killed. However, there are few biomaterials with the ability of both cancer therapy and bone regeneration until now. Here, we fabricated a 3D-printed bioceramic scaffold with a uniformly self-assembled Ca-P/polydopamine nanolayer surface. Taking advantage of biocompatibility, biodegradability and the excellent photothermal effect of polydopamine, the bifunctional scaffolds with mussel-inspired nanostructures could be used as a satisfactory and controllable photothermal agent, which effectively induced tumor cell death in vitro, and significantly inhibited tumor growth in mice. In addition, owing to the nanostructured surface, the prepared polydopamine-modified bioceramic scaffolds could support the attachment and proliferation of rabbit bone mesenchymal stem cells (rBMSCs), and significantly promoted the formation of new bone tissues in rabbit bone defects even under photothermal treatment. Therefore, the mussel-inspired nanostructures in 3D-printed bioceramic exhibited a remarkable capability for both cancer therapy and bone regeneration, offering a promising strategy to construct bifunctional biomaterials which could be widely used for therapy of tumor-induced tissue defects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis, characterization and photocatalytic activity of magnetically separable hexagonal Ni/ZnO nanostructure

NASA Astrophysics Data System (ADS)

Senapati, Samarpita; Srivastava, Suneel K.; Singh, Shiv B.

2012-09-01

centered cubic Ni and hexagonal wurtzite ZnO without any traces of impurity. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nickel nanoparticles under solvothermal conditions. These nickel nanoparticles, when subjected to reflux, formed the hexagonal zinc oxide coated nickel nanostructure. Fourier transform infrared (FTIR) spectra, photoluminescence (PL) and Raman studies also confirmed the presence of zinc oxide in the hybrid nanostructure. The growth mechanism for the development of the hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure has also been proposed. The appearance of the hysteresis loop, in the as-prepared Ni/ZnO hybrid nanostructure, demonstrated its ferromagnetic character at room temperature. The hexagonal Ni/ZnO nanostructure also acts as an efficient photocatalyst in the degradation of methylene blue under ultraviolet light irradiation. It is observed that the catalytic efficiency of the hybrid nanocatalyst is better compared to pure zinc oxide. Most importantly, the Ni/ZnO catalyst could also be easily separated, simply by applying an external magnetic field, and reused. Electronic supplementary information (ESI) available: Fig. S1 Ni/ZnO hybrid nanostructure prepared using (a) 0.195 and (b) 0.25 M [Zn2+] at 90 °C Fig. S2 FTIR spectra of nickel nanoparticles prepared at 140 °C (a), and Ni/ZnO hybrid nanostructure prepared using (b) 0.063, (c) 0.125, (d) 0.195 and (e) 0.25 M [Zn2+]; Fig. S3 Raman spectra of Ni/ZnO nanostructure prepared using (a) 0.063, (b) 0.125, (c) 0.195 and (d) 0.25 M [Zn2+]; Fig. S4 Room temperature PL spectra of (a) ZnO and (b) Ni/ZnO nanostructure prepared using 0.25 M [Zn2+]. See DOI: 10.1039/c2nr31831h

Nanostructured cerium oxide: preparation, characterization, and application in energy and environmental catalysis

DOE PAGES

Tang, Wen-Xiang; Gao, Pu-Xian

2016-11-10

Nanostructured cerium oxide (CeO 2) with outstanding physical and chemical properties has attracted extensive interests over the past few decades in environment and energy-related applications. With controllable synthesis of nanostructured CeO 2, much more features were technologically brought out from defect chemistry to structure-derived effects. This paper highlights recent progress on the synthesis and characterization of nanostructured ceria-based materials as well as the traditional and new applications. Specifically, several typical applications based on the desired ceria nanostructures are focused to showcase the importance of nanostructure-derived effects. Moreover, some challenges and perspectives on the nanostructured ceria are presented, such as defectsmore » controlling and retainment, scale-up fabrication, and monolithic devices. Hopefully, this paper can provide an improved understanding of nanostructured CeO 2 and offer new opportunities to promote the further research and applications in the future.« less

Structural and optical properties of cobalt doped multiferroics BiFeO3 nanostructure thin films

NASA Astrophysics Data System (ADS)

Prasannakumara, R.; Naik, K. Gopalakrishna

2018-05-01

Bismuth ferrite (BiFeO3) and Cobalt doped BiFeO3 (BiFe1-XCoXO3) nanostructure thin films were deposited on glass substrates by the sol-gel spin coating method. The X-ray diffraction patterns (XRD) of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films showed distorted rhombohedral structure. The shifting of peaks to higher angles was observed in cobalt doped BiFeO3. The surface morphology of the BiFeO3 and BiFe1-XCoXO3 nanostructure thin films were studied using FESEM, an increase in grain size was observed as Co concentration increases. The thickness of the nanostructure thin films was examined using FESEM cross-section. The EDX studies confirmed the elemental composition of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films. The optical characterizations of the grown nanostructure thin films were carried out using FTIR, it confirms the existence of Fe-O and Bi-O bands and UV-Visible spectroscopy shows the increase in optical band gap of the BiFeO3 nanostructure thin films with Co doping by ploting Tauc plot.

PH Tester Gauge Repeatability and Reproducibility Study for WO3 Nanostructure Hydrothermal Growth Process

NASA Astrophysics Data System (ADS)

Abd Rashid, Amirul; Hayati Saad, Nor; Bien Chia Sheng, Daniel; Yee, Lee Wai

2014-06-01

PH value is one of the important variables for tungsten trioxide (WO3) nanostructure hydrothermal synthesis process. The morphology of the synthesized nanostructure can be properly controlled by measuring and controlling the pH value of the solution used in this facile synthesis route. Therefore, it is very crucial to ensure the gauge used for pH measurement is reliable in order to achieve the expected result. In this study, gauge repeatability and reproducibility (GR&R) method was used to assess the repeatability and reproducibility of the pH tester. Based on ANOVA method, the design of experimental metrics as well as the result of the experiment was analyzed using Minitab software. It was found that the initial GR&R value for the tester was at 17.55 % which considered as acceptable. To further improve the GR&R level, a new pH measuring procedure was introduced. With the new procedure, the GR&R value was able to be reduced to 2.05%, which means the tester is statistically very ideal to measure the pH of the solution prepared for WO3 hydrothermal synthesis process.

Complex and oriented ZnO nanostructures.

PubMed

Tian, Zhengrong R; Voigt, James A; Liu, Jun; McKenzie, Bonnie; McDermott, Matthew J; Rodriguez, Mark A; Konishi, Hiromi; Xu, Huifang

2003-12-01

Extended and oriented nanostructures are desirable for many applications, but direct fabrication of complex nanostructures with controlled crystalline morphology, orientation and surface architectures remains a significant challenge. Here we report a low-temperature, environmentally benign, solution-based approach for the preparation of complex and oriented ZnO nanostructures, and the systematic modification of their crystal morphology. Using controlled seeded growth and citrate anions that selectively adsorb on ZnO basal planes as the structure-directing agent, we prepared large arrays of oriented ZnO nanorods with controlled aspect ratios, complex film morphologies made of oriented nanocolumns and nanoplates (remarkably similar to biomineral structures in red abalone shells) and complex bilayers showing in situ column-to-rod morphological transitions. The advantages of some of these ZnO structures for photocatalytic decompositions of volatile organic compounds were demonstrated. The novel ZnO nanostructures are expected to have great potential for sensing, catalysis, optical emission, piezoelectric transduction, and actuations.

Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: Structure, Preparation and Application

PubMed Central

Naseri, Neda; Valizadeh, Hadi; Zakeri-Milani, Parvin

2015-01-01

Lipid nanoparticles (LNPs) have attracted special interest during last few decades. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are two major types of Lipid-based nanoparticles. SLNs were developed to overcome the limitations of other colloidal carriers, such as emulsions, liposomes and polymeric nanoparticles because they have advantages like good release profile and targeted drug delivery with excellent physical stability. In the next generation of the lipid nanoparticle, NLCs are modified SLNs which improve the stability and capacity loading. Three structural models of NLCs have been proposed. These LNPs have potential applications in drug delivery field, research, cosmetics, clinical medicine, etc. This article focuses on features, structure and innovation of LNPs and presents a wide discussion about preparation methods, advantages, disadvantages and applications of LNPs by focusing on SLNs and NLCs. PMID:26504751

Preparation of K-doped TiO2 nanostructures by wet corrosion and their sunlight-driven photocatalytic performance

NASA Astrophysics Data System (ADS)

Shin, Eunhye; Jin, Saera; Kim, Jiyoon; Chang, Sung-Jin; Jun, Byung-Hyuk; Park, Kwang-Won; Hong, Jongin

2016-08-01

K-doped TiO2 nanowire networks were prepared by the corrosion reaction of Ti nanoparticles in an alkaline (potassium hydroxide: KOH) solution. The prepared nanostructures were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD) and photoluminescence (PL) spectra. Their sunlight-driven photocatalytic activity was also investigated with differently charged dye molecules, such as methylene blue, rhodamine B and methyl orange. The adsorption of the dye molecules on the photocatalyst surface would play a critical role in their selective photodegradation under sunlight illumination.

Preparation of Ni3B2O6 nanosheet-based flowerlike architecture by a precursor method and its electrochemical properties in lithium-ion battery

NASA Astrophysics Data System (ADS)

Liang, Pan; Du, Lu; Wang, Xia; Liu, Zhi-Hong

2014-11-01

A novel flower-like nickel borate of Ni3B2O6 nanostructure was prepared through a hydrothermal treatment and sequential thermal decomposition of precursor without employing any template or surfactant. All the samples were characterized by XRD, IR, XPS, TG-DTA, nitrogen adsorption, SEM and TEM. The flower-like Ni3B2O6 nanostructure was self-assembled by nanosheets with the thickness of about 40 nm. The electrochemical properties in lithium-ion battery of flower-like Ni3B2O6 nanostructure were studied by the cyclic voltammetry, galvanostatic cycling test, and electrochemical impedance spectroscopy, which showed it had a high initial discharge capacity and a good reversibility.

A study of 3-dimensionally periodic carbon nanostructures

NASA Astrophysics Data System (ADS)

Yin, Ming; Bleiweiss, Michael; Amirzadeh, Jafar; Datta, Timir; Arammash, Fouzi

2012-02-01

Electronic structures with intricate periodic 3-dimensional arrangements at the submicron scale were investigated. These may be fabricated using artificial porous opal substrates as the templates in which the targeted conducting medium is introduced. In the past these materials were reported to show interesting electronic behaviors. [Michael Bleiweiss, et al ``Localization and Related Phenomena in Multiply Connected Nanostructured,'' BAPS, Z30.011, Nanostructured Materials Session, March 2001, Seattle]. Several materials were studied in particular disordered carbon which has been reported to show quantum transport including fractional hall steps. The results of these measurements, including the observation of localization phenomena, will be discussed. Comparisons will be made with literature data.

The annealing investigation on morphology and photoluminescence properties of In2O3 1-D nanostructures in resistive evaporation mechanism

NASA Astrophysics Data System (ADS)

Shariati, Mohsen; Ghafouri, Vahid

2014-02-01

Synthesis of In2O3 nanostructures grown on Si substrate by the resistive evaporation of metallic indium granules followed by dry oxidation process has been articulated. To prepare nucleation growth sites, selected samples pre-annealed around indium melting point in free-oxygen atmosphere and then to fabricate 1-D nanostructures, they annealed in a horizontal thermal furnace in presence of argon and oxygen. For comparison, one sample, the same origin as initially pre-annealed samples, was excluded in pre-annealing process but presented in annealing step. Characterization of the products with FESEM revealed that the pre-annealed obtained nanostructures are mostly nanorod and nanowire with different morphologies. For the comparative sample, no 1-D structures achieved. X-ray diffraction (XRD) patterns for pre-annealed samples indicated that they are crystalline and the comparative one is polycrystalline. Photoluminescence (PL) measurements carried out at room temperature revealed that emission band shifted to shorter wavelength from pre-annealed samples to comparative one.

Quantitative 3D electromagnetic field determination of 1D nanostructures from single projection

DOE PAGES

Phatak, C.; Knoop, L. de; Houdellier, F.; ...

2016-05-01

One-dimensional (1D) nanostructures have been regarded as the most promising building blocks for nanoelectronics and nanocomposite material systems as well as for alternative energy applications. Although they result in confinement of a material, their properties and interactions with other nanostructures are still very much three-dimensional (3D) in nature. In this work, we present a novel method for quantitative determination of the 3D electromagnetic fields in and around 1D nanostructures using a single electron wave phase image, thereby eliminating the cumbersome acquisition of tomographic data. Using symmetry arguments, we have reconstructed the 3D magnetic field of a nickel nanowire as wellmore » as the 3D electric field around a carbon nanotube field emitter, from one single projection. The accuracy of quantitative values determined here is shown to be a better fit to the physics at play than the value obtained by conventional analysis. Moreover the 3D reconstructions can then directly be visualized and used in the design of functional 3D architectures built using 1D nanostructures.« less

Quantitative 3D electromagnetic field determination of 1D nanostructures from single projection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phatak, C.; Knoop, L. de; Houdellier, F.

One-dimensional (1D) nanostructures have been regarded as the most promising building blocks for nanoelectronics and nanocomposite material systems as well as for alternative energy applications. Although they result in confinement of a material, their properties and interactions with other nanostructures are still very much three-dimensional (3D) in nature. In this work, we present a novel method for quantitative determination of the 3D electromagnetic fields in and around 1D nanostructures using a single electron wave phase image, thereby eliminating the cumbersome acquisition of tomographic data. Using symmetry arguments, we have reconstructed the 3D magnetic field of a nickel nanowire as wellmore » as the 3D electric field around a carbon nanotube field emitter, from one single projection. The accuracy of quantitative values determined here is shown to be a better fit to the physics at play than the value obtained by conventional analysis. Moreover the 3D reconstructions can then directly be visualized and used in the design of functional 3D architectures built using 1D nanostructures.« less

Morphology Dependent Photocatalytic Activity of α-MoO3 Nanostructures Towards Mutagenic Acridine Orange Dye.

PubMed

2015-06-01

The morphological evolutions of orthorhombic molybdenum oxide nanostructures with high crystalline nature have been successfully synthesized by combining low-temperature sol-gel and annealing processes. Strong influence of gelation temperature is a factor facilitated to control the material morphology. Morphological transformations like nanospheres, nanoplatelets, mixtures of hexagonal platelets, and one-dimensional nanobars were obtained. The possible morphological formation mechanism has been proposed as a self-assemble process of nucleation and a mechanism for particle growth by Ostwald ripening. The as-prepared nanostructures were recognized as photocatalysts for the degradation of Acridine Orange under Ultra Violet light. The obtained mixed morphology (hexagonal nanoplatelets and nanobars) showed a high photocatalytic property to degrade mutagenic Acridine Orange dye. Moreover, they could be easily recycled without changing the photocatalytic activity due to their 1-Dimensional and 2-Dimensional nanostructure property.

Electrochemical synthesis and photoelectrochemical properties of grass-like nanostructured α-Fe2O3 photoanodes for use in solar water oxidation

NASA Astrophysics Data System (ADS)

Hanedar, Yesim; Demir, Umit; Oznuluer, Tuba

2016-10-01

Grass-like nanostructured α-Fe2O3 photoelectrodes were prepared for the first time through a simple cathodic electrodeposition method from an oxygenated aqueous solution of Fe3+ at room temperature without using surfactant, capping agents or any other additives. The α-Fe2O3 electrodeposits were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis absorption and photoelectrochemical (PEC) techniques. The SEM and XRD results indicated that the as-deposited α-Fe2O3 are composed of single crystalline nanoleaves. The formation mechanisms of α-Fe2O3 have also been proposed based on a series of cyclic voltammetric and XPS studies. This new electrochemical method is expected to be a useful technique for the fabrication of single crystalline and photoactive α-Fe2O3 nanostructures directly onto the electrode surface, which is required in most applications, such as energy conversion and storage and sensors.

Uniform Fe3O4 coating on flower-like ZnO nanostructures by atomic layer deposition for electromagnetic wave absorption.

PubMed

Wan, Gengping; Wang, Guizhen; Huang, Xianqin; Zhao, Haonan; Li, Xinyue; Wang, Kan; Yu, Lei; Peng, Xiange; Qin, Yong

2015-11-21

An elegant atomic layer deposition (ALD) method has been employed for controllable preparation of a uniform Fe3O4-coated ZnO (ZnO@Fe3O4) core-shell flower-like nanostructure. The Fe3O4 coating thickness of the ZnO@Fe3O4 nanostructure can be tuned by varying the cycle number of ALD Fe2O3. When serving as additives for microwave absorption, the ZnO@Fe3O4-paraffin composites exhibit a higher absorption capacity than the ZnO-paraffin composites. For ZnO@500-Fe3O4, the effective absorption bandwidth below -10 dB can reach 5.2 GHz and the RL values below -20 dB also cover a wide frequency range of 11.6-14.2 GHz when the coating thickness is 2.3 mm, suggesting its potential application in the treatment of the electromagnetic pollution problem. On the basis of experimental observations, a mechanism has been proposed to understand the enhanced microwave absorption properties of the ZnO@Fe3O4 composites.

3D porous and ultralight carbon hybrid nanostructure fabricated from carbon foam covered by monolayer of nitrogen-doped carbon nanotubes for high performance supercapacitors

NASA Astrophysics Data System (ADS)

He, Shuijian; Hou, Haoqing; Chen, Wei

2015-04-01

3D porous and self-supported carbon hybrids are promising electrode materials for supercapacitor application attributed to their prominent properties such as binder-free electrode fabrication process, excellent electric conductivity and high power density etc. We present here a facile chemical vapor deposition method to fabricate a novel 3D flexible carbon hybrid nanostructure by growing a monolayer of nitrogen-doped carbon nanotubes on the skeleton of carbon foam (N-CNTs/CF) with Fe nanoparticle as catalyst. With such 3D porous, flexible and ultralight carbon nanostructure as binder-free electrode material, large surface area is available and fast ionic transport is facilitated. Moreover, the carbon-based network can provide excellent electronic conductivity. The electrochemical studies demonstrate that the supercapacitor constructed from the N-CNTs/CF hybrid exhibit high power density of 69.3 kW kg-1 and good stability with capacitance retention ration above 95% after cycled at 50 A g-1 for 5000 cycles. Therefore, the prepared porous N-CNTs/CF nanostructure is expected to be a type of excellent electrode material for electrical double layer capacitors.

3D-fabrication of tunable and high-density arrays of crystalline silicon nanostructures

NASA Astrophysics Data System (ADS)

Wilbers, J. G. E.; Berenschot, J. W.; Tiggelaar, R. M.; Dogan, T.; Sugimura, K.; van der Wiel, W. G.; Gardeniers, J. G. E.; Tas, N. R.

2018-04-01

In this report, a procedure for the 3D-nanofabrication of ordered, high-density arrays of crystalline silicon nanostructures is described. Two nanolithography methods were utilized for the fabrication of the nanostructure array, viz. displacement Talbot lithography (DTL) and edge lithography (EL). DTL is employed to perform two (orthogonal) resist-patterning steps to pattern a thin Si3N4 layer. The resulting patterned double layer serves as an etch mask for all further etching steps for the fabrication of ordered arrays of silicon nanostructures. The arrays are made by means of anisotropic wet etching of silicon in combination with an isotropic retraction etch step of the etch mask, i.e. EL. The procedure enables fabrication of nanostructures with dimensions below 15 nm and a potential density of 1010 crystals cm-2.

Studies of Nano-structured Se77Sb23- x Ge x Thin Films Prepared by Physical Vapor Condensation Technique

NASA Astrophysics Data System (ADS)

Alvi, M. A.

2017-02-01

Bulk Se77Sb23- x Ge x material with x = 4 and 12 was prepared by employing a melt quench technique. Its amorphous as well as glassy nature was confirmed by x-ray diffraction analysis and nonisothermal differential scanning calorimetry measurements. The physical vapor condensation technique was applied to prepare nanostructured thin films of Se77Sb23- x Ge x material. The surface morphology of the films was examined using field-emission scanning electron microscopy, revealing average particle size between 20 nm and 50 nm. Systematic investigation of optical absorption data indicated that the optical transition was indirect in nature. The dark conductivity (dc conductivity) of nano-structured Se77Sb23- x Ge x thin films was also investigated at temperatures from 313 K to 463 K, revealing that it tended to increase with increasing temperature. Analyses of our experimental data also indicate that the conduction is due to thermally supported tunneling of charge carriers in confined states close to the band edges. The calculated values of activation energy agree well with the optical bandgap.

Outstanding supercapacitive properties of Mn-doped TiO2 micro/nanostructure porous film prepared by anodization method

PubMed Central

Ning, Xuewen; Wang, Xixin; Yu, Xiaofei; Zhao, Jianling; Wang, Mingli; Li, Haoran; Yang, Yang

2016-01-01

Mn-doped TiO2 micro/nanostructure porous film was prepared by anodizing a Ti-Mn alloy. The film annealed at 300 °C yields the highest areal capacitance of 1451.3 mF/cm2 at a current density of 3 mA/cm2 when used as a high-performance supercapacitor electrode. Areal capacitance retention is 63.7% when the current density increases from 3 to 20 mA/cm2, and the capacitance retention is 88.1% after 5,000 cycles. The superior areal capacitance of the porous film is derived from the brush-like metal substrate, which could greatly increase the contact area, improve the charge transport ability at the oxide layer/metal substrate interface, and thereby significantly enhance the electrochemical activities toward high performance energy storage. Additionally, the effects of manganese content and specific surface area of the porous film on the supercapacitive performance were also investigated in this work. PMID:26940546

Controlled Self-Assembly of Low-Dimensional Alq3 Nanostructures from 1D Nanowires to 2D Plates via Intermolecular Interactions

NASA Astrophysics Data System (ADS)

Gu, Jianmin; Yin, Baipeng; Fu, Shaoyan; Jin, Cuihong; Liu, Xin; Bian, Zhenpan; Li, Jianjun; Wang, Lu; Li, Xiaoyu

2018-03-01

Due to the intense influence of the shape and size of the photon building blocks on the limitation and guidance of optical waves, an important strategy is the fabrication of different structures. Herein, organic semiconductor tris-(8-hydroxyquinoline)aluminium (Alq3) nanostructures with controllable morphology, ranging from one-dimensional nanowires to two-dimensional plates, have been prepared through altering intermolecular interactions with employing the anti-solvent diffusion cooperate with solvent-volatilization induced self-assembly method. The morphologies of the formed nanostructures, which are closely related to the stacking modes of the molecules, can be exactly controlled by altering the polarity of anti-solvents that can influence various intermolecular interactions. The synthesis strategy reported here can potentially be extended to other functional organic nanomaterials.

Nanostructured TiO2-based gas sensors with enhanced sensitivity to reducing gases

PubMed Central

Kusior, Anna; Trenczek-Zajac, Anita

2016-01-01

2D TiO2 thin films and 3D flower-like TiO2-based nanostructures, also decorated with SnO2, were prepared by chemical and thermal oxidation of Ti substrates, respectively. The crystal structure, morphology and gas sensing properties of the TiO2-based sensing materials were investigated. 2D TiO2 thin films crystallized mainly in the form of rutile, while the flower-like 3D nanostructures as anatase. The sensor based on the 2D TiO2 showed the best performance for H2 detection, while the flower-like 3D nanostructures exhibited enhanced selectivity to CO(CH3)2 after sensitization by SnO2 nanoparticles. The sensor response time was of the order of several seconds. Their fast response, high sensitivity to selected gas species, improved selectivity and stability suggest that the SnO2-decorated flower-like 3D nanostructures are a promising material for application as an acetone sensor. PMID:28144521

High Curie temperature and coercivity performance of Fe3-xCrxSe4 nanostructures.

PubMed

Li, Shao-jie; Li, Da; Liu, Wei; Zhang, Zhidong

2015-03-12

Monoclinic Fe3-xCrxSe4 nanostructures (0≤x≤2.5) were synthesized using a high-temperature solution chemical method. With increasing the Cr doping, the peak positions in the X-ray diffraction (XRD) patterns of Fe3-xCrxSe4 nanostructures slightly shifted to lower 2θ values due to the changes in lattice parameters. Expansions in the unit cell volumes of Fe3-xCrxSe4 nanostructures (x>0.3) may have been responsible for enhancing the ferromagnetic (FM) interaction between magnetic ions, which resulted in a significant increase in the Curie temperature (TC) from 331 K for Fe3Se4 to 429 K for FeCr2Se4, distinctly differing from the magnetic properties of the corresponding bulk materials. A room-temperature coercivity (HC) analysis showed an obvious increase from 3.2 kOe for Fe3Se4 to 12 kOe for Fe2.3Cr0.7Se4 nanostructure, but gradually decreased upon further increasing the Cr content.

The continuous and persistent periodical growth induced by substrate accommodation in In2O3 nanostructure chains and their photoluminescence properties

NASA Astrophysics Data System (ADS)

Shariati, Mohsen

2015-03-01

The growth of pyramidal and triangular beaded In2O3 nanocrystal chains by using oxygen-assisted thermal evaporation, substrate accommodation and condensation method has been articulated. Self-assembled In2O3 nanocrystal chains have been synthesized by the vapor-solid (VS) and vapor-liquid-solid (VLS) growth mechanism and also through controlling the kinetics factors (saturation ratio). A periodical one-dimensional (1-D) and persistent (0-D) growth was proposed to explain the formation of lateral nanostructures, and this formation aspect was ascribed to the alternate 1-D and 0-D growth. Preparing the needed growth factor, the In2O3 nanocrystal chains extended to several micrometers. The growth mechanism analysis was useful to realize the relation between the kinetics factors and the complex nanostructure. The morphology and size of nanocrystals intensively were changed by oxygen concentration and led to interesting photoluminescence property.

Synthesis and Characterization of Mimosa Pudica Leaves Shaped α-Iron Oxide Nanostructures for Ethanol Chemical Sensor Applications.

PubMed

Kim, S H; Ibrahim, Ahmed A; Kumar, R; Umar, Ahmad; Abaker, M; Hwang, S W; Baskoutas, S

2016-03-01

Herein, the synthesis of mimosa pudica leaves shaped a-iron oxide (α-Fe2O3) nanostructures is reported through simple and facile hydrothermal process. The prepared α-Fe2O3 nanostructures were characterized in terms of their morphological, structural, compositional and optical properties through a variety of characterization techniques such as FESEM, EDS, XRD, FTIR and Raman spectroscopy. The detailed characterizations revealed the well-crystallinity and dense growth of mimosa pudica leaf shaped α-Fe2O3 nanostructures. Further, the prepared nanomaterials were used as efficient electron mediator to fabricate sensitive ethanol chemical sensor. The fabricated sensor exhibited a high sensitivity of -30.37 μAmM(-1) cm(-2) and low detection limit of -0.62 μM. The observed linear dynamic range (LDR) was in the range from 10 μM-0.625 μM.

Thermal behaviour of GdCo1-xMnxO3 cobaltates

NASA Astrophysics Data System (ADS)

Thakur, Rasna; Thakur, Rajesh K.; Gaur, N. K.

2018-05-01

With the objective of exploring the unknown thermodynamic behavior of GdCo1-xMnxO3 family, we present here an investigation of the temperature-dependent (10K≤T≤1000K) thermodynamic properties of GdCo1-xMnxO3 (x=0.1 to 0.8). The specific heat of GdCoO3 with Mn doping in the perovskite structure at B-site has been studied by means of a Modified Rigid Ion Model (MRIM). The cohesive energy, specific heat (C), volume thermal expansion (α) and Gruneisen parameter (γ) of GdCo1-xMnxO3 compounds are also discussed.

Temperature and acidity effects on WO{sub 3} nanostructures and gas-sensing properties of WO{sub 3} nanoplates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Huili; Liu, Zhifang; Yang, Jiaqin

2014-09-15

Graphical abstract: Generally, large acid quantity and high temperature are beneficial to the formation of anhydrous WO3, but the acidity effect on the crystal phase is weaker than that of temperature. Large acid quantity is found helpful to the oriented growth of tungsten oxides, forming a nanoplate-like product. - Highlights: • Large acid quantity is propitious to the oriented growth of a WO{sub 3} nanoplate. • Effect of acid quantity on crystal phases of products is weaker than that of temperature. • One step hydrothermal synthesis of WO{sub 3} is facile and can be easily scaled up. • A WO{submore » 3} nanoplate shows a fast response and distinct sensing selectivity to acetone gas. - Abstract: WO{sub 3} nanostructures were successfully synthesized by a facile hydrothermal method using Na{sub 2}WO{sub 4}·2H{sub 2}O and HNO{sub 3} as raw materials. They are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The specific surface area was obtained from N{sub 2} adsorption–desorption isotherm. The effects of the amount of HNO{sub 3}, hydrothermal temperature and reaction time on the crystal phases and morphologies of the WO{sub 3} nanostructures were investigated in detail, and the reaction mechanism was discussed. Large amount of acid is found for the first time to be helpful to the oriented growth of tungsten oxides, forming nanoplate-like products, while hydrothermal temperature has more influence on the crystal phase of the product. Gas-sensing properties of the series of as-prepared WO{sub 3} nanoplates were tested by means of acetone, ethanol, formaldehyde and ammonia. One of the WO{sub 3} nanoplates with high specific surface area and high crystallinity displays high sensitivity, fast response and distinct sensing selectivity to acetone gas.« less

Synthesis of hierarchical three-dimensional copper oxide nanostructures through a biomineralization-inspired approach

NASA Astrophysics Data System (ADS)

Fei, Xiang; Shao, Zhengzhong; Chen, Xin

2013-08-01

Three-dimensional (3D) copper oxide (CuO) nanostructures were synthesized in a regenerated Bombyx mori silk fibroin aqueous solution at room temperature. In the synthesis process, silk fibroin served as the template and helped to form the hierarchical CuO nanostructures by self-assembly. Cu(OH)2 nanowires were formed initially, and then they transformed into almond-like CuO nanostructures with branched edges and a compact middle. The size of the final CuO nanostructures can be tuned by varying the concentration of silk fibroin in the reaction system. A possible mechanism has been proposed based on various characterization techniques, such as scanning and transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis. The synthesized CuO nanostructured material has been evaluated as an anode material for lithium ion batteries, and the result showed that they had a good electrochemical performance. The straightforward energy-saving method developed in this research may provide a useful preparation strategy for other functional inorganic materials through an environmentally friendly process.Three-dimensional (3D) copper oxide (CuO) nanostructures were synthesized in a regenerated Bombyx mori silk fibroin aqueous solution at room temperature. In the synthesis process, silk fibroin served as the template and helped to form the hierarchical CuO nanostructures by self-assembly. Cu(OH)2 nanowires were formed initially, and then they transformed into almond-like CuO nanostructures with branched edges and a compact middle. The size of the final CuO nanostructures can be tuned by varying the concentration of silk fibroin in the reaction system. A possible mechanism has been proposed based on various characterization techniques, such as scanning and transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis. The synthesized CuO nanostructured material has been evaluated as an anode material for lithium ion batteries, and the result

Domain alignment within ferroelectric/dielectric PbTiO 3 /SrTiO 3 superlattice nanostructures

DOE PAGES

Park, Joonkyu; Mangeri, John; Zhang, Qingteng; ...

2018-01-01

The ferroelectric domain pattern within lithographically defined PbTiO 3/SrTiO 3ferroelectric/dielectric heteroepitaxial superlattice nanostructures is strongly influenced by the edges of the structures.

Nanostructured thick 3D nanofibrous scaffold can induce bone.

PubMed

Eap, Sandy; Morand, David; Clauss, François; Huck, Olivier; Stoltz, Jean-François; Lutz, Jean-Christophe; Gottenberg, Jacques-Eric; Benkirane-Jessel, Nadia; Keller, Laetitia; Fioretti, Florence

2015-01-01

Designing unique nanostructured biomimetic materials is a new challenge in modern regenerative medicine. In order to develop functional substitutes for damaged organs or tissues, several methods have been used to create implants able to regenerate robust and durable bone. Electrospinning produces nonwoven scaffolds based on polymer nanofibers mimicking the fibrillar organization of bone extracellular matrix. Here, we describe a biomimetic 3D thick nanofibrous scaffold obtained by electrospinning of the biodegradable, bioresorbable and FDA-approved polymer, poly(ε-caprolactone). Such scaffold presents a thickness reaching one centimeter. We report here the demonstration that the designed nanostructured implant is able to induce in vivo bone regeneration.

Ultrasound-assisted synthesis of nano-structured Zinc(II)-based metal-organic frameworks as precursors for the synthesis of ZnO nano-structures.

PubMed

Bigdeli, Fahime; Ghasempour, Hosein; Azhdari Tehrani, Alireza; Morsali, Ali; Hosseini-Monfared, Hassan

2017-07-01

A 3D, porous Zn(II)-based metal-organic framework {[Zn 2 (oba) 2 (4-bpmn)]·(DMF) 1.5 } n (TMU-21), (4-bpmn=N,N'-Bis-pyridin-4-ylmethylene-naphtalene-1,5-diamine, H 2 oba=4,4'-oxybis(benzoic acid)) with nano-rods morphology under ultrasonic irradiation at ambient temperature and atmospheric pressure was prepared and characterized by scanning electron microscopy. Sonication time and concentration of initial reagents effects on the size and morphology of nano-structured MOFs were studied. Also {[Zn 2 (oba) 2 (4-bpmn)] (TMU-21) and {[Zn 2 (oba) 2 (4-bpmb)] (TMU-6), 4-bpmb=N,N'-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) were easily prepared by mechanochemical synthesis. Nanostructures of Zinc(II) oxide were obtained by calcination of these compounds and their de-solvated analogue as activated MOFs, at 550°C under air atmosphere. As a result of that, different Nanostructures of Zinc(II) oxide were obtained. The ZnO nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

Fluorine-doped NiO nanostructures: Structural, morphological and spectroscopic studies

NASA Astrophysics Data System (ADS)

Singh, Kulwinder; Kumar, Manjeet; Singh, Dilpreet; Singh, Manjinder; Singh, Paviter; Singh, Bikramjeet; Kaur, Gurpreet; Bala, Rajni; Thakur, Anup; Kumar, Akshay

2018-05-01

Nanostructured NiO has been prepared by co-precipitation method. In this study, the effect of fluorine doping (1, 3 and 5 wt. %) on the structural, morphological as well as optical properties of NiO nanostructures has been studied. X-ray diffraction (XRD) has employed for studying the structural properties. Cubic crystal structure of NiO was confirmed by the XRD analysis. Crystallite size increased with increase in doping concentration. Nelson-Riley factor (NRF) analysis indicated the presence of defect states in the synthesized samples. Field emission scanning electron microscopy showed the spherical morphology of the synthesized samples and also revealed that the particle size varied with dopant content. The optical properties were studied using UV-Visible Spectroscopy. The results indicated that the band gap energy of the synthesized nanostructures decreased with increase in doping concentration upto 3% but increased as the doping concentration was further raised to 5%. This can be ascribed to the defect states variations in the synthesized samples. The results suggested that the synthesized nanostructures are promising candidate for optoelectronic as well as gas sensing applications.

Effects of annealing temperature on the physicochemical, optical and photoelectrochemical properties of nanostructured hematite thin films prepared via electrodeposition method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phuan, Yi Wen; Chong, Meng Nan, E-mail: Chong.Meng.Nan@monash.edu; Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 46150 Selangor DE

2015-09-15

Highlights: • Nanostructured hematite thin films were synthesized via electrodeposition method. • Effects of annealing on size, grain boundary and PEC properties were examined. • Photocurrents generation was enhanced when the thin films were annealed at 600 °C. • The highest photocurrent density of 1.6 mA/cm{sup 2} at 0.6 V vs Ag/AgCl was achieved. - Abstract: Hematite (α-Fe{sub 2}O{sub 3}) is a promising photoanode material for hydrogen production from photoelectrochemical (PEC) water splitting due to its wide abundance, narrow band-gap energy, efficient light absorption and high chemical stability under aqueous environment. The key challenge to the wider utilisation of nanostructuredmore » hematite-based photoanode in PEC water splitting, however, is limited by its low photo-assisted water oxidation caused by large overpotential in the nominal range of 0.5–0.6 V. The main aim of this study was to enhance the performance of hematite for photo-assisted water oxidation by optimising the annealing temperature used during the synthesis of nanostructured hematite thin films on fluorine-doped tin oxide (FTO)-based photoanodes prepared via the cathodic electrodeposition method. The resultant nanostructured hematite thin films were characterised using field emission-scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR) for their elemental composition, average nanocrystallites size and morphology; phase and crystallinity; UV-absorptivity and band gap energy; and the functional groups, respectively. Results showed that the nanostructured hematite thin films possess good ordered nanocrystallites array and high crystallinity after annealing treatment at 400–600 °C. FE-SEM images illustrated an increase in the average hematite nanocrystallites size from 65 nm to 95 nm when the annealing temperature was varied from 400 �

Development of batch producible hot embossing 3D nanostructured surface-enhanced Raman scattering chip technology

NASA Astrophysics Data System (ADS)

Huang, Chu-Yu; Tsai, Ming-Shiuan

2017-09-01

The main purpose of this study is to develop a batch producible hot embossing 3D nanostructured surface-enhanced Raman chip technology for high sensitivity label-free plasticizer detection. This study utilizing the AAO self-assembled uniform nano-hemispherical array barrier layer as a template to create a durable nanostructured nickel mold. With the hot embossing technique and the durable nanostructured nickel mold, we are able to batch produce the 3D Nanostructured Surface-enhanced Raman Scattering Chip with consistent quality. In addition, because of our SERS chip can be fabricated by batch processing, the fabrication cost is low. Therefore, the developed method is very promising to be widespread and extensively used in rapid chemical and biomolecular detection applications.

Biological activity and photostability of biflorin micellar nanostructures.

PubMed

Santana, Edson R B; Ferreira-Neto, João P; Yara, Ricardo; Sena, Kêsia X F R; Fontes, Adriana; Lima, Cláudia S A

2015-05-13

Capraria biflora L. is a shrub from the Scrophulariaceae family which produces in its roots a compound named biflorin, an o-naphthoquinone that shows activity against Gram-positive bacteria and fungi and also presents antitumor and antimetastatic activities. However, biflorin is hydrophobic and photosensitive. These properties make its application difficult. In this work we prepared biflorin micellar nanostructures looking for a more effective vehiculation and better preservation of the biological activity. Biflorin was obtained, purified and characterized by UV-Vis, infrared (IR) and 1H- and 13C-NMR. Micellar nanostructures of biflorin were then assembled with Tween 80®, Tween 20® and saline (0.9%) and characterized by UV-Vis spectroscopy and dynamic light scattering (DLS). The results showed that the micellar nanostructures were stable and presented an average size of 8.3 nm. Biflorin micellar nanostructures' photodegradation was evaluated in comparison with biflorin in ethanol. Results showed that the biflorin in micellar nanostructures was better protected from light than biflorin dissolved in ethanol, and also indicated that biflorin in micelles were efficient against Gram-positive bacteria and yeast species. In conclusion, the results showed that the micellar nanostructures could ensure the maintenance of the biological activity of biflorin, conferring photoprotection. Moreover, biflorin vehiculation in aqueous media was improved, favoring its applicability in biological systems.

Coherent 3D nanostructure of γ-Al{sub 2}O{sub 3}: Simulation of whole X-ray powder diffraction pattern

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakharukova, V.P., E-mail: verapakh@catalysis.ru; Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk; Research and Educational Center for Energy Efficient Catalysis, Novosibirsk State University, Novosibirsk 630090

2017-02-15

The structure and nanostructure features of nanocrystalline γ-Al{sub 2}O{sub 3} obtained by dehydration of boehmite with anisotropic platelet-shaped particles were investigated. The original models of 3D coherent nanostructure of γ-Al{sub 2}O{sub 3} were constructed. The models of nanostructured γ-Al{sub 2}O{sub 3} particles were first confirmed by a direct simulation of powder X–Ray diffraction (XRD) patterns using the Debye Scattering Equation (DSE) with assistance of high-resolution transmission electron microscopy (HRTEM) study. The average crystal structure of γ-Al{sub 2}O{sub 3} was shown to be tetragonally distorted. The experimental results revealed that thin γ-Al{sub 2}O{sub 3} platelets were heterogeneous on a nanometer scalemore » and nanometer-sized building blocks were separated by partially coherent interfaces. The XRD simulation results showed that a specific packing of the primary crystalline blocks in the nanostructured γ-Al{sub 2}O{sub 3} particles with formation of planar defects on (001), (100), and (101) planes nicely accounted for pronounced diffuse scattering, anisotropic peak broadening and peak shifts in the experimental XRD pattern. The identified planar defects in cation sublattice seem to be described as filling cation non-spinel sites in existing crystallographic models of γ-Al{sub 2}O{sub 3} structure. The overall findings provided an insight into the complex nanostructure, which is intrinsic to the metastable γ-Al{sub 2}O{sub 3} oxide. - Highlights: • Thin plate-like crystallites of γ-Al{sub 2}O{sub 3} were obtained. • Models of 3D coherent nanostructure of γ-Al{sub 2}O{sub 3} were constructed. • Models were verified by simulating XRD patterns using the Debye Scattering Equation. • Specific broadening of XRD peaks was explained in terms of planar defects. • Primary crystalline blocks in γ-Al{sub 2}O{sub 3} are separated by partially coherent interfaces.« less

Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions

DOE PAGES

Ishihara, Hidetaka; Chen, Yen-Chang; De Marco, Nicholas; ...

2016-12-07

The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedralmore » shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape.« less

Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions.

PubMed

Ishihara, Hidetaka; Chen, Yen-Chang; De Marco, Nicholas; Lin, Oliver; Huang, Chih-Meng; Limsakoune, Vipawee; Chou, Yi-Chia; Yang, Yang; Tung, Vincent

2016-12-07

The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedral shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape.

Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions

PubMed Central

Ishihara, Hidetaka; Chen, Yen-Chang; De Marco, Nicholas; Lin, Oliver; Huang, Chih-Meng; Limsakoune, Vipawee; Chou, Yi-Chia; Yang, Yang; Tung, Vincent

2016-01-01

The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedral shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape. PMID:27924857

Interfacing nanostructures to biological cells

DOEpatents

Chen, Xing; Bertozzi, Carolyn R.; Zettl, Alexander K.

2012-09-04

Disclosed herein are methods and materials by which nanostructures such as carbon nanotubes, nanorods, etc. are bound to lectins and/or polysaccharides and prepared for administration to cells. Also disclosed are complexes comprising glycosylated nanostructures, which bind selectively to cells expressing glycosylated surface molecules recognized by the lectin. Exemplified is a complex comprising a carbon nanotube functionalized with a lipid-like alkane, linked to a polymer bearing repeated .alpha.-N-acetylgalactosamine sugar groups. This complex is shown to selectively adhere to the surface of living cells, without toxicity. In the exemplified embodiment, adherence is mediated by a multivalent lectin, which binds both to the cells and the .alpha.-N-acetylgalactosamine groups on the nanostructure.

Temperature-feedback direct laser reshaping of silicon nanostructures

NASA Astrophysics Data System (ADS)

Aouassa, M.; Mitsai, E.; Syubaev, S.; Pavlov, D.; Zhizhchenko, A.; Jadli, I.; Hassayoun, L.; Zograf, G.; Makarov, S.; Kuchmizhak, A.

2017-12-01

Direct laser reshaping of nanostructures is a cost-effective and fast approach to create or tune various designs for nanophotonics. However, the narrow range of required laser parameters along with the lack of in-situ temperature control during the nanostructure reshaping process limits its reproducibility and performance. Here, we present an approach for direct laser nanostructure reshaping with simultaneous temperature control. We employ thermally sensitive Raman spectroscopy during local laser melting of silicon pillar arrays prepared by self-assembly microsphere lithography. Our approach allows establishing the reshaping threshold of an individual nanostructure, resulting in clean laser processing without overheating of the surrounding area.

Reliable contact fabrication on nanostructured Bi2Te3-based thermoelectric materials.

PubMed

Feng, Shien-Ping; Chang, Ya-Huei; Yang, Jian; Poudel, Bed; Yu, Bo; Ren, Zhifeng; Chen, Gang

2013-05-14

A cost-effective and reliable Ni-Au contact on nanostructured Bi2Te3-based alloys for a solar thermoelectric generator (STEG) is reported. The use of MPS SAMs creates a strong covalent binding and more nucleation sites with even distribution for electroplating contact electrodes on nanostructured thermoelectric materials. A reliable high-performance flat-panel STEG can be obtained by using this new method.

Facile synthesis of BiOI in hierarchical nanostructure preparation and its photocatalytic application to organic dye removal and biocidal effect of bacteria.

PubMed

Long, Yang; Wang, Yi; Zhang, Dun; Ju, Peng; Sun, Yan

2016-11-01

Novel BiOI hierarchical nanostructures with porous architecture was prepared at room temperature by an economical, facile and rapid route. The coupling adsorption and degradation efficiency of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) could achieve 98.7%, 43.2%, 76.9% within 180min in the presence of BiOI, respectively. BiOI hierarchical nanostructures also exhibit excellent effective biocidal performances, and the disinfection rate of the typical biofouling bacteria Bacillus sp. and Pseudoalteromonas sp. could reach 99.9% and 99.8% in 60min, respectively. The circulate photocatalytic degradation of RhB experiment verified the good stability and reusability of BiOI hierarchical nanostructures. Based on active specie trapping experiments, the superoxide radicals (O2(-)) and holes (h(+)) were proved to be the main reactive species in the BiOI-based system. The obviously enhanced coupling adsorption and photocatalytic degradation performance of BiOI hierarchical nanostructures could be mainly attributed to the large surface area (64.5m(2)/g), negatively charged surface and the intrinsic electron structure. This study provides a new strategy to develop novel photocatalysts for water treatment and marine antifouling. Copyright © 2016 Elsevier Inc. All rights reserved.

Preparation, characterization and gas sensing performance of BaTiO3 nanostructured thin films

NASA Astrophysics Data System (ADS)

Suryawanshi, Dinesh N.; Pathan, Idris G.; Bari, Anil. R.; Patil, Lalchand A.

2018-05-01

Spray pyrolysis techniques was employed to prepare BaTiO3 thin films. AR grade solutions of Barium chloride (0.05 M) and Titanium chloride (0.05 M) were mixed in the proportion of 30:70, 50:50 and 70:30. The solutions were sprayed on quartz substrate heated at 350°C temperature to obtain the films. These thin films were annealed for a two hours at 600°C in air medium respectively. The prepared thin films were characterized using XRD, FESEM, EDAX, TEM. The electrical and gas sensing properties of these films were investigated. 50:50 film showed better response to Liquid Petroleum Gas (LPG) as compare 30:70 and 70:30 films.

Low temperature nucleation of Griffiths Phase in Co doped LaMnO3 nanostructures

NASA Astrophysics Data System (ADS)

Adeela, N.; Khan, U.; Naz, S.; Iqbal, M.; Irfan, M.; Cheng, Y.

2017-11-01

We have reported magnetic properties of La1-xCoxMnO3 nanostructures synthesized by hydrothermal route. The crystal structure has been characterized by X-ray diffraction (XRD) technique, which shows rhombohedral perovskite structure at room temperature. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) have been used to analyse morphology and chemical composition of prepared nanoparticles. Magnetic hysteresis loops of all the samples exhibit ferromagnetic behaviour at 10 K. Inverse susceptibility graphs as a function of temperature represent deviation from Curie Weiss law. The indication for short range ferromagnetic clusters well above Curie temperature is observed due to the Griffiths Phase (GP). It is proposed that the presence of GP arises from induced size effects of La and Co ions.

Synthesis of porphyrin nanostructures

DOEpatents

Fan, Hongyou; Bai, Feng

2014-10-28

The present disclosure generally relates to self-assembly methods for generating porphyrin nanostructures. For example, in one embodiment a method is provided that includes preparing a porphyrin solution and a surfactant solution. The porphyrin solution is then mixed with the surfactant solution at a concentration sufficient for confinement of the porphyrin molecules by the surfactant molecules. In some embodiments, the concentration of the surfactant is at or above its critical micelle concentration (CMC), which allows the surfactant to template the growth of the nanostructure over time. The size and morphology of the nanostructures may be affected by the type of porphyrin molecules used, the type of surfactant used, the concentration of the porphyrin and surfactant the pH of the mixture of the solutions, and the order of adding the reagents to the mixture, to name a few variables.

Synthesis and properties of graphene oxide/graphene nanostructures

NASA Astrophysics Data System (ADS)

Kapitanova, O. O.; Panin, G. N.; Baranov, A. N.; Kang, T. W.

2012-05-01

We report preparation of graphene oxide (GO)/graphene (G) nanostructures and their structural, optical and electrical properties. GO was synthesized through oxidation of graphite by using the modified Hummer's method, in which a long oxidation time was combined with a highly effective method for purifying the reaction products. The obtained GO was partially reduced (r-GO) by adding ascorbic acid and thermal annealing. An electrical reduction/oxidation process in r-GO under an electric field was used to form and control the GO/G nanostructures and the potential barrier at the interface. After the treatment, the ratio of the intensity of peak G (1578 cm-1) to that of peak D (1357 cm-1) in Raman spectra of the samples is increased, which is attributed to an increase in the ratio between the sp2 and sp3 regions. The electrical and the luminescence characteristics of the GO/G nanostructures were investigated.

Domain alignment within ferroelectric/dielectric PbTiO 3 /SrTiO 3 superlattice nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Joonkyu; Mangeri, John; Zhang, Qingteng

The ferroelectric domain pattern within lithographically defined PbTiO 3/SrTiO 3 ferroelectric/dielectric heteroepitaxial superlattice nanostructures is strongly influenced by the edges of the structures. Synchrotron X-ray nanobeam diffraction reveals that the spontaneously formed 180° ferroelectric stripe domains exhibited by such superlattices adopt a configuration in rectangular nanostructures in which domain walls are aligned with long patterned edges. The angular distribution of X-ray diffuse scattering intensity from nanodomains indicates that domains are aligned within an angular range of approximately 20° with respect to the edges. Computational studies based on a time-dependent Landau–Ginzburg–Devonshire model show that the preferred direction of the alignment resultsmore » from lowering of the bulk and electrostrictive contributions to the free energy of the system due to the release of the lateral mechanical constraint. This unexpected alignment appears to be intrinsic and not a result of distortions or defects caused by the patterning process. Thus, our work demonstrates how nanostructuring and patterning of heteroepitaxial superlattices allow for pathways to create and control ferroelectric structures that may appear counterintuitive.« less

Domain alignment within ferroelectric/dielectric PbTiO 3 /SrTiO 3 superlattice nanostructures

DOE PAGES

Park, Joonkyu; Mangeri, John; Zhang, Qingteng; ...

2018-01-22

The ferroelectric domain pattern within lithographically defined PbTiO 3/SrTiO 3 ferroelectric/dielectric heteroepitaxial superlattice nanostructures is strongly influenced by the edges of the structures. Synchrotron X-ray nanobeam diffraction reveals that the spontaneously formed 180° ferroelectric stripe domains exhibited by such superlattices adopt a configuration in rectangular nanostructures in which domain walls are aligned with long patterned edges. The angular distribution of X-ray diffuse scattering intensity from nanodomains indicates that domains are aligned within an angular range of approximately 20° with respect to the edges. Computational studies based on a time-dependent Landau–Ginzburg–Devonshire model show that the preferred direction of the alignment resultsmore » from lowering of the bulk and electrostrictive contributions to the free energy of the system due to the release of the lateral mechanical constraint. This unexpected alignment appears to be intrinsic and not a result of distortions or defects caused by the patterning process. Thus, our work demonstrates how nanostructuring and patterning of heteroepitaxial superlattices allow for pathways to create and control ferroelectric structures that may appear counterintuitive.« less

Boron-based nanostructures: Synthesis, functionalization, and characterization

NASA Astrophysics Data System (ADS)

Bedasso, Eyrusalam Kifyalew

Boron-based nanostructures have not been explored in detail; however, these structures have the potential to revolutionize many fields including electronics and biomedicine. The research discussed in this dissertation focuses on synthesis, functionalization, and characterization of boron-based zero-dimensional nanostructures (core/shell and nanoparticles) and one-dimensional nanostructures (nanorods). The first project investigates the synthesis and functionalization of boron-based core/shell nanoparticles. Two boron-containing core/shell nanoparticles, namely boron/iron oxide and boron/silica, were synthesized. Initially, boron nanoparticles with a diameter between 10-100 nm were prepared by decomposition of nido-decaborane (B10H14) followed by formation of a core/shell structure. The core/shell structures were prepared using the appropriate precursor, iron source and silica source, for the shell in the presence of boron nanoparticles. The formation of core/shell nanostructures was confirmed using high resolution TEM. Then, the core/shell nanoparticles underwent a surface modification. Boron/iron oxide core/shell nanoparticles were functionalized with oleic acid, citric acid, amine-terminated polyethylene glycol, folic acid, and dopamine, and boron/silica core/shell nanoparticles were modified with 3-(amino propyl) triethoxy silane, 3-(2-aminoethyleamino)propyltrimethoxysilane), citric acid, folic acid, amine-terminated polyethylene glycol, and O-(2-Carboxyethyl)polyethylene glycol. A UV-Vis and ATR-FTIR analysis established the success of surface modification. The cytotoxicity of water-soluble core/shell nanoparticles was studied in triple negative breast cancer cell line MDA-MB-231 and the result showed the compounds are not toxic. The second project highlights optimization of reaction conditions for the synthesis of boron nanorods. This synthesis, done via reduction of boron oxide with molten lithium, was studied to produce boron nanorods without any

Fabrication of tunable plasmonic 3D nanostructures for SERS applications

NASA Astrophysics Data System (ADS)

Ozbay, Ayse; Yuksel, Handan; Solmaz, Ramazan; Kahraman, Mehmet

2016-03-01

Surface-enhanced Raman scattering (SERS) is a powerful technique used for characterization of biological and nonbiological molecules and structures. Since plasmonic properties of the nanomaterials is one of the most important factor influencing SERS activity, tunable plasmonic properties (wavelength of the surface plasmons and magnitude of the electromagnetic field generated on the surface) of SERS substrates are crucial in SERS studies. SERS enhancement can be maximized by controlling of plasmonic properties of the nanomaterials. In this study, a novel approach to fabricate tunable plasmonic 3D nanostructures based on combination of soft lithography and nanosphere lithography is studied. Spherical latex particles having different diameters are uniformly deposited on glass slides with convective assembly method. The experimental parameters for the convective assembly are optimized by changing of latex spheres concentration, stage velocity and latex particles volume placed between to two glass slides that staying with a certain angle to each other. Afterwards, polydimethylsiloxane (PDMS) elastomer is poured on the deposited latex particles and cured to obtain nanovoids on the PDMS surfaces. The diameter and depth of the nanovoids on the PDMS surface are controlled by the size of the latex particles. Finally, fabricated nanovoid template on the PDMS surfaces are filled with the silver coating to obtain plasmonic 3D nanostructures. Characterization of the fabricated surfaces is performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SERS performance of fabricated 3D plasmonic nanostructures will be evaluated using Raman reporter molecules.

3D magnetic nanostructures grown by focused electron and ion beam induced deposition

NASA Astrophysics Data System (ADS)

Fernandez-Pacheco, Amalio

Three-dimensional nanomagnetism is an emerging research area, where magnetic nanostructures extend along the whole space, presenting novel functionalities not limited to the substrate plane. The development of this field could have a revolutionary impact in fields such as electronics, the Internet of Things or bio-applications. In this contribution, I will show our recent work on 3D magnetic nanostructures grown by focused electron and ion beam induced deposition. This 3D nano-printing techniques, based on the local chemical vapor deposition of a gas via the interaction with electrons and ions, makes the fabrication of complex 3D magnetic nanostructures possible. First, I will show how by exploiting different growth regimes, suspended Cobalt nanowires with modulated diameter can be patterned, with potential as domain wall devices. Afterwards, I will show recent results where the synthesis of Iron-Gallium alloys can be exploited in the field of artificial multiferroics. Moreover, we are developing novel methodologies combining physical vapor deposition and 3D nano-printing, creating Permalloy 3D nanostrips with controllable widths and lengths up to a few microns. This approach has been extended to more complex geometries by exploiting advanced simulation growth techniques combining Monte Carlo and continuum model methods. Throughout the talk, I will show the methodology we are following to characterize 3D magnetic nanostructures, by combining magneto-optical Kerr effect, scanning probe microscopy and electron and X-R magnetic imaging, and I will highlight some of the challenges and opportunities when studying these structures. I acknowledge funding from EPSRC and the Winton Foundation.

Short peptide-directed synthesis of one-dimensional platinum nanostructures with controllable morphologies

PubMed Central

Tao, Kai; Wang, Jiqian; Li, Yanpeng; Xia, Daohong; Shan, Honghong; Xu, Hai; Lu, Jian R.

2013-01-01

Although one dimensional (1D) Pt nanostructures with well-defined sizes and shapes have fascinating physiochemical properties, their preparation remains a great challenge. Here we report an easy and novel synthesis of 1D Pt nanostructures with controllable morphologies, through the combination of designer self-assembling I3K and phage-displayed P7A peptides. The nanofibrils formed via I3K self-assembly acted as template. Pt precursors ((PtCl4)2− and (PtCl6)2−) were immobilized by electrostatic interaction on the positively charged template surface and subsequent reduction led to the formation of 1D Pt nanostructures. P7A was applied to tune the continuity of the Pt nanostructures. Here, the electrostatic repulsion between the deprotonated C-terminal carboxyl groups of P7A molecules was demonstrated to play a key role. We finally showed that continuous and ordered 1D Pt morphology had a significantly improved electrochemical performance for the hydrogen and methanol electro-oxidation in comparison with either 1D discrete Pt nanoparticle assemblies or isolated Pt nanoparticles. PMID:23995118

Physics of SrTiO3-based heterostructures and nanostructures: a review.

PubMed

Pai, Yun-Yi; Tylan-Tyler, Anthony; Irvin, Patrick; Levy, Jeremy

2018-02-09

This review provides a summary of the rich physics expressed within SrTiO 3 -based heterostructures and nanostructures. The intended audience is researchers who are working in the field of oxides, but also those with different backgrounds (e.g., semiconductor nanostructures). After reviewing the relevant properties of SrTiO 3 itself, we will then discuss the basics of SrTiO 3 -based heterostructures, how they can be grown, and how devices are typically fabricated. Next, we will cover the physics of these heterostructures, including their phase diagram and coupling between the various degrees of freedom. Finally, we will review the rich landscape of quantum transport phenomena, as well as the devices that elicit them.

Zerumbone-loaded nanostructured lipid carriers: preparation, characterization, and antileukemic effect

PubMed Central

Rahman, Heshu Sulaiman; Rasedee, Abdullah; How, Chee Wun; Abdul, Ahmad Bustamam; Zeenathul, Nazariah Allaudin; Othman, Hemn Hassan; Saeed, Mohamed Ibrahim; Yeap, Swee Keong

2013-01-01

Zerumbone, a natural dietary lipophilic compound with low water solubility (1.296 mg/L at 25°C) was used in this investigation. The zerumbone was loaded into nanostructured lipid carriers using a hot, high-pressure homogenization technique. The physicochemical properties of the zerumbone-loaded nanostructured lipid carriers (ZER-NLC) were determined. The ZER-NLC particles had an average size of 52.68 ± 0.1 nm and a polydispersity index of 0.29 ± 0.004 μm. Transmission electron microscopy showed that the particles were spherical in shape. The zeta potential of the ZER-NLC was −25.03 ± 1.24 mV, entrapment efficiency was 99.03%, and drug loading was 7.92%. In vitro drug release of zerumbone from ZER-NLC was 46.7%, and for a pure zerumbone dispersion was 90.5% over 48 hours, following a zero equation. Using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human T-cell acute lymphoblastic leukemia (Jurkat) cells, the half maximal inhibitory concentration (IC50) of ZER-NLC was 5.64 ± 0.38 μg/mL, and for free zerumbone was 5.39 ± 0.43 μg/mL after 72 hours of treatment. This study strongly suggests that ZER-NLC have potential as a sustained-release drug carrier system for the treatment of leukemia. PMID:23946649

Some aspects of applying nanostructured materials in air filtration, water filtration and electrical engineering

NASA Astrophysics Data System (ADS)

Kimmer, Dusan; Vincent, Ivo; Lovecka, Lenka; Kazda, Tomas; Giurg, Adam; Skorvan, Ondrej

2017-05-01

Nanostructures prepared from nanofibres and nanostructured composites prepared from nanofibres and fillers are gradually becoming increasingly demanded materials for applications in various industrial branches connected with catalysis, environment protection (air filtration, waste water treatment, sound absorption), in biological engineering, electronics (battery separators, electrode materials), etc. Selected applications of these materials prepared in the company SPUR a.s. are summed up in the following presentation.

Homo-endotaxial one-dimensional Si nanostructures

DOE PAGES

Song, Jiaming; Hudak, Bethany M.; Sims, Hunter; ...

2017-11-29

One-dimensional (1D) nanostructures are highly sought after, both for their novel electronic properties as well as for their improved functionality. However, due to their nanoscale dimensions, these properties are significantly affected by the environment in which they are embedded. Here in this paper, we report on the creation of 1D homo-endotaxial Si nanostructures, i.e. 1D Si nanostructures with a lattice structure that is uniquely different from the Si diamond lattice in which they are embedded. We use scanning tunneling microscopy and spectroscopy, scanning transmission electron microscopy, density functional theory, and conductive atomic force microscopy to elucidate their formation and properties.more » Depending on kinetic constraints during growth, they can be prepared as endotaxial 1D Si nanostructures completely embedded in crystalline Si, or underneath a stripe of amorphous Si containing a large concentration of Bi atoms. Lastly, these homo-endotaxial 1D Si nanostructures have the potential to be useful components in nanoelectronic devices based on the technologically mature Si platform.« less

Application of glucose as a green capping agent and reductant to fabricate CuI micro/nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tavakoli, Farnosh; Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir; Ghanbari, Davood

Graphical abstract: - Highlights: • CuI nanostructures were prepared via a simple precipitation method. • Glucose as a green capping agent and reductant was applied. • The effect of glucose concentration on the morphology of CuI was investigated. • According to XRD results, pure cubic phase CuI have been formed by using glucose. - Abstract: In this work, CuI micro/nanostructures have been successfully prepared via a simple precipitation route at room temperature. By using glucose as a clean reducing agent with different concentrations, CuI micro/nanostructures with various morphologies were obtained. Besides glucose, Na{sub 2}SO{sub 3}, KBH{sub 4} and N{sub 2}H{submore » 4}·H{sub 2}O have been applied as reductant. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy, X-ray energy dispersive spectroscopy (EDS) and Fourier transformed infrared (FT-IR) spectroscopy were used to characterize the as-produced CuI micro/nanostructures. According to the XRD results, it was found that pure cubic phase CuI have been formed by using glucose.« less

Porous α-Fe2O3 nanostructures and their lithium storage properties as full cell configuration against LiFePO4

NASA Astrophysics Data System (ADS)

Veluri, P. S.; Shaligram, A.; Mitra, S.

2015-10-01

A two step approach for synthesis of porous α-Fe2O3 nanostructures has been realized via polyol method by complexing iron oxalate with ethylene glycol. Crystalline Fe2O3 samples with different porosities are obtained by calcination of Fe-Ethylene glycol complex at various temperatures. The as-prepared porous Fe2O3 structures exhibit promising lithium storage performance at high current rates. It is observed that the calcination temperature and the resultant porosity have a significant effect on capacity and cycling stability. Samples calcined at high temperature (600 °C) demonstrates stable cycle life with capacity retention of 1077 mAh g-1 at 500 mA g-1 current rate after 50 charge-discharge cycles. Samples calcined at temperatures of 500 and 600 °C display stable cycle life and high rate capability with reversible capacity of 930 mAh g-1 and 688 mAh g-1 at 5 A g-1, respectively. Impregnation of electrodes with electrolyte before cell fabrication shows enhanced electrochemical performance. The viability of Fe2O3 porous nanostructures as prospective anode material examined against commercial LiFePO4 cathode shows promising electrochemical performance.

SrZnO nanostructures grown on templated <0001> Al2O3 substrates by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Labis, Joselito P.; Alanazi, Anwar Q.; Albrithen, Hamad A.; El-Toni, Ahmed Mohamed; Hezam, Mahmoud; Elafifi, Hussein Elsayed; Abaza, Osama M.

2017-09-01

The parameters of pulsed laser deposition (PLD) have been optimized to design different nanostructures of Strontium-alloyed zinc oxide (SrZnO). In this work, SrZnO nanostructures are grown on <0001>Al2O3 substrates via two-step templating/seeding approach. In the temperature range between 300 - 750 oC and O2 background pressures between 0.01 and 10 Torr, the growth conditions have been tailored to grow unique pointed leaf-like- and pitted olive-like nanostructures. Prior to the growth of the nanostructures, a thin SrZnO layer that serves as seed layer/template is first deposited on the Al2O3 substrates at ˜300oC and background oxygen pressure of 10 mTorr. The optical properties of the nanostructures were examined by UV/Vis spectroscopy and photoluminescence (PL), while the structures/morphologies were examined by SEM, TEM, and XRD. The alloyed SrZnO nanostructures, grown by ablating ZnO targets with 5, 10, 25% SrO contents, have in common a single-crystal hexagonal nanostructure with (0002) preferential orientation and have shown remarkable changes in the morphological and optical properties of the materials. To date, this is the only reported work on optimization of laser ablation parameters to design novel SrZnO nanostructures in the 5-25% alloying range, as most related Sr-doped ZnO studies were done below 7% doping. Although the physical properties of ZnO are modified via Sr doping, the mechanism remains unclear. The PLD-grown SrZnO nanostructures were directly grown onto the Al2O3 substrates; thus making these nanomaterials very promising for potential applications in biosensors, love-wave filters, solar cells, and ultrasonic oscillators.

Design, Fabrication, and Characterization of Hematite (α-Fe2O3) Nanostructures

NASA Astrophysics Data System (ADS)

Jansi Rani, B.; Mageswari, R.; Ravi, G.; Ganesh, V.; Yuvakkumar, R.

2017-12-01

The influence of processing parameters on the physicochemical properties of hematite α-Fe2O3 nanostructures was investigated. X-ray diffraction results revealed the hematite phase rhombohedral structure. Scanning electron microscope results explored nanospheres, nanohexagonal platelets, nanoellipsoids, distorted nanocubes, and interconnected platelets nanostructures. Rhombohedral single-phase hematite was confirmed through five Raman active modes. 2 P 3/2 (1) → 2 P 1/2 transition in photoluminescence spectra and Fourier-transform infrared spectroscopy band observed at 555 cm-1 revealed the hematite formation. The highest specific capacitance value of 151.09 F/g for scan rate of 10 mV/s was obtained for the hydrothermal-assisted product using an Fe(NO3)2·9H2O precursor in KOH electrolyte solutions.

Synthesis, characterization, and properties of low-dimensional nanostructured materials

NASA Astrophysics Data System (ADS)

Hu, Xianluo

2007-05-01

Nanometer scale structures represent an exciting and rapidly expanding area of research. Studies on new physical/chemical properties and applications of nanomaterials and nanostructures are possible only when nanostructured materials are made available with desired size, morphology, crystal and microstructure, and composition. Thus, controlled synthesis of nanomaterials is the essential aspect of nanotechnology. This thesis describes the development of simple and versatile solution-based approaches to synthesize low-dimensional nanostructures. The first major goal of this research is to design and fabricate morphology-controlled alpha-Fe 2O3 nanoarchitectures in aqueous solution through a programmed microwave-assisted hydrothermal route, taking advantage of microwave irradiation and hydrothermal effects. Free-standing alpha-Fe2O3 nanorings are prepared by hydrolysis of FeCl3 in the presence of phosphate ions. The as-formed architecture of alpha-Fe2O 3 nanorings is an exciting new member in the family of iron oxide nanostructures. Our preliminary results demonstrate that sensors made of the alpha-Fe 2O3 nanorings exhibit high sensitivity not only for bio-sensing of hydrogen peroxide in a physiological solution but also for gas-sensing of alcohol vapor at room temperature. Moreover, monodisperse alpha-Fe 2O3 nanocrystals with continuous aspect-ratio tuning and fine shape control are achieved by controlling the experimental conditions. The as-formed alpha-Fe2O3 exhibits shape-dependent infrared optical properties. The growth process of colloidal alpha-Fe 2O3 crystals in the presence of phosphate ions is discussed. In addition, through an efficient microwave-assisted hydrothermal process, self-assembled hierarchical alpha-Fe2O3 nanoarchitectures are synthesized on a large scale. The second major goal of this research is to develop convenient microwave-hydrothermal approaches for the fabrication of carbon-based nanocomposites: (1) A one-pot solution-phase route, namely

Controlled Growth of Parallel Oriented ZnO Nanostructural Arrays on Ga2O3 Nanowires

DTIC Science & Technology

2008-11-01

Controlled Growth of Parallel Oriented ZnO Nanostructural Arrays on Ga2O3 Nanowires Lena Mazeina,* Yoosuf N. Picard, and Sharka M. Prokes Electronics...Manuscript ReceiVed NoVember 6, 2008 ABSTRACT: Novel hierarchical ZnO- Ga2O3 nanostructures were fabricated via a two stage growth process. Nanowires of Ga2O3 ...nanobrushes (NBs) with Ga2O3 as the core and ZnO as the branches self-assembling symmetrically in six equiangular directions around the core

Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

PubMed Central

Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

2016-01-01

The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5–20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures. PMID:26902260

Controlling BaZrO3 nanostructure orientation in YBa2Cu3O{}_{7-\\delta } films for a three-dimensional pinning landscape

NASA Astrophysics Data System (ADS)

Wu, J. Z.; Shi, J. J.; Baca, F. J.; Emergo, R.; Wilt, J.; Haugan, T. J.

2015-12-01

The orientation phase diagram of self-assembled BaZrO3 (BZO) nanostructures in c-oriented YBa2Cu3O{}7-δ (YBCO) films on flat and vicinal SrTiO3 substrates was studied experimentally with different dopant concentrations and vicinal angles and theoretically using a micromechanical model based on the theory of elasticity. The organized BZO nanostructure configuration was found to be tunable, between c-axis to ab-plane alignment, by the dopant concentration in the YBCO film matrix strained via lattice mismatched substrates. The correlation between the local strain caused by the BZO doping and the global strain on the matrix provides a unique approach for controllable growth of dopant nanostructure landscapes. In particular, a mixed phase of the c-axis-aligned nanorods and the ab-plane-aligned planar nanostructures can be obtained, leading to a three-dimensional pinning landscape with single impurity doping and much improved J c in almost all directions of applied magnetic field.

Surfactant-assisted hydrothermal crystallization of nanostructured lithium metasilicate (Li{sub 2}SiO{sub 3}) hollow spheres: (I) Synthesis, structural and microstructural characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz-Landeros, J.; Departamento de Ingenieria Metalurgica, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, IPN, UPALM, Av. Instituto Politecnico Nacional s/n, CP 07738, Mexico DF; Contreras-Garcia, M.E.

Lithium metasilicate (Li{sub 2}SiO{sub 3}) was successfully synthesized using a hydrothermal process in the presence of different surfactants with cationic, non-ionic and anionic characters. The samples obtained were compared to a sample prepared by the conventional solid-state reaction method. The structural and microstructural characterizations of different Li{sub 2}SiO{sub 3} powders were performed using various techniques. Diffraction analyses revealed the successful crystallization of pure Li{sub 2}SiO{sub 3} single phase by hydrothermal technique, even without further heat-treatments and independent of the surfactant used. Electron microscopy analyses revealed that Li{sub 2}SiO{sub 3} powders were composed of uniform micrometric particles with a hollow spheremore » morphology and nanostructured walls. Finally, different thermal analyses showed that Li{sub 2}SiO{sub 3} samples preserved their structure and microstructure after further thermal treatments. Specific aspects regarding the formation mechanism of the spherical aggregates under hydrothermal conditions are discussed, and there is a special emphasis on the effect of the synthesis pathway on the morphological characteristics. -- Graphical abstract: Li{sub 2}SiO{sub 3} was synthesized using a hydrothermal process in the presence of different surfactants. Li{sub 2}SiO{sub 3} powders were composed of uniform micrometric particles with a hollow sphere morphology and nanostructured walls. Display Omitted Highlights: {yields} Pure Li{sub 2}SiO{sub 3} was synthesized by the hydrothermal method. {yields} Surfactant addition produced microstructural and morphological variations. {yields} TEM reveled the generation of nanostructured hollow spheres.« less

Hierarchical Co(OH)2 nanostructures/glassy carbon electrode derived from Co(BTC) metal-organic frameworks for glucose sensing

NASA Astrophysics Data System (ADS)

He, Juan; Lu, Xingping; Yu, Jie; Wang, Li; Song, Yonghai

2016-07-01

A novel Co(OH)2/glassy carbon electrode (GCE) has been fabricated via metal-organic framework (MOF)-directed method. In the strategy, the Co(BTC, 1,3,5-benzentricarboxylic acid) MOFs/GCE was firstly prepared by alternately immersing GCE in Co2+ and BTC solution based on a layer-by-layer method. And then, the Co(OH)2 with hierarchical flake nanostructure/GCE was constructed by immersing Co(BTC) MOFs/GCE into 0.1 M NaOH solution at room temperature. Such strategy improves the distribution of hierarchical Co(OH)2 nanostructures on electrode surface greatly, enhances the stability of nanomaterials on the electrode surface, and increases the use efficiency of the Co(OH)2 nanostructures. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and Raman spectra were used to characterize the Co(BTC) MOFs/GCE and Co(OH)2/GCE. Based on the hierarchical Co(OH)2 nanostructures/GCE, a novel and sensitive nonenzymatic glucose sensor was developed. The good performance of the resulted sensor toward the detection of glucose was ascribed to hierarchical flake nanostructures, good mechanical stability, excellent distribution, and large specific surface area of Co(OH)2 nanostructures. The proposed preparation method is simple, efficient, and cheap .

Field Emission and Nanostructure of Carbon Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merkulov, V.I.; Lowndes, D.H.; Baylor, L.R.

1999-11-29

The results of field emission measurements of various forms of carbon films are reported. It is shown that the films nanostructure is a crucial factor determining the field emission properties. In particular, smooth, pulsed-laser deposited amorphous carbon films with both high and low sp3 contents are poor field emitters. This is similar to the results obtained for smooth nanocrystalline, sp2-bonded carbon films. In contrast, carbon films prepared by hot-filament chemical vapor deposition (HE-CVD) exhibit very good field emission properties, including low emission turn-on fields, high emission site density, and excellent durability. HF-CVD carbon films were found to be predominantly sp2-bonded.more » However, surface morphology studies show that these films are thoroughly nanostructured, which is believed to be responsible for their promising field emission properties.« less

Preparation and characterization of Pt loaded WO3 films suitable for gas sensing applications

NASA Astrophysics Data System (ADS)

Jolly Bose, R.; Illyasukutty, Navas; Tan, K. S.; Rawat, R. S.; Vadakke Matham, Murukesan; Kohler, Heinz; Mahadevan Pillai, V. P.

2018-05-01

This paper presents the preparation of nanostructured platinum (Pt) loaded tungsten oxide (WO3) thin films by radio frequency (RF) magnetron sputtering technique. Even though, Pt loading does not produce any phase change in WO3 lattice, it deteriorates the crystalline quality and induces defects on WO3 films. The Pt loading in WO3 has profound impact on structural and optical properties of the films by which the particle size, lattice strain and optical band gap energy are reduced. Nanoporous film with reduced particle size is obtained for 5 wt% Pt loaded WO3 sample which is crucial for gas sensors. Hence the sensing response of 5 wt% Pt loaded sample is tested towards carbon monoxide (CO) gas along with pure WO3 sample. The sensing response of Pt loaded sample is nearly 15 times higher than pure WO3 sample in non-humid ambience at an operating temperature 200 °C. This indicates the suitability of the prepared films for gas sensors. The sensing response of pure WO3 film depends on the humidity while the Pt loaded WO3 film shows stable response in both humid and non-humid ambiences.

Preparation and properties on hollow nano-structured smoke material

NASA Astrophysics Data System (ADS)

Liu, Xiang-cui; Dai, Meng-yan; Fang, Guo-feng; Shi, Wei-dong; Cheng, Xiang; Liu, Hai-feng; Zhang, Tong

2013-09-01

In recent years, the weapon systems of laser guidance and infrared (IR) imaging guidance have been widely used in modern warfare because of their high precision and strong anti-interference. Notwithstanding, military smoke, as a rapid and effective passive jamming means, can effectively counteract the attack of enemy precision-guided weapons by scattering and absorbability. Conventional smoke has good attenuation capability only to visible light (0.4-0.76 μm), but hardly any effect to other electromagnetic wave band. The weapon systems of laser guidance and IR imaging guidance usually work in broad band, including near IR (1-3 μm), middle IR (3-5 μm), far IR (8-14 μm), and so on. Accordingly, exploiting and using new efficient obscurant materials, which is one of the important factors that develop smoke technology, have become a focus and attracted more interests around the world. Then nano-structured materials that are developing very quickly have turned into our new choice. Hollow nano-structured materials (HNSM) have many special properties because of their nano-size wall-thickness and sub-micron grain-size. After a lot of HNSM were synthesized in this paper, their physical and chemical properties, including grain size, phase composition, microstructure, optical properties and resistivity were tested and analysed. Then the experimental results of the optical properties showed that HNSM exhibit excellent wave-absorbing ability in ultraviolet, visible and infrared regions. On the basis of the physicochemmical properties, HNSM are firstly applied in smoke technology field. And the obscuration performance of HNSM smoke was tested in smoke chamber. The testing waveband included 1.06μm and 10.6μm laser, 3-5μm and 8-14μm IR radiation. Then the main parameters were obtained, including the attenuation rate, the transmission rate, the mass extinction coefficient, the efficiency obscuring time, and the sedimentation rate, etc. The main parameters of HNSM smoke were

In2O3-ZnO heterostructure development in electrical and photoluminescence properties of In2O3 1-D nanostructures

NASA Astrophysics Data System (ADS)

Shariati, M.; Ghafouri, V.

2014-05-01

Indium Oxide quasi one-dimensional (1D) nanostructures known as nanowires and nanorods synthesis using the thermal evaporation method, has been articulated. To nucleate growth sites, substrate seeding promoted 1D nanostructures growth. The catalyst-mediated growth mechanism showed more favorable morphologies and physical properties in under vacuum conditions associated with bottom-up technique. Scanning electron microscopy (SEM) results showed that the Zn-doped 1D nanostructures had spherical caps. The X-ray diffraction (XRD) pattern and energy-dispersive X-ray (EDX) spectrum indicated that these caps intensively associated with ZnO. Therefore, it was reasonable that the vapor-liquid-solid mechanism (VLS) was responsible for the growth of the In2O3-ZnO heterostructure nanowires. This technique enhances optical and electrical properties in nanostructures. The photoluminescence (PL) analysis in Zn-doped In2O3 nanowires and nanorods shows that the intensity of the visible and UV-region emissions overwhelmingly increases and resistance measurement professes the improvement of linear conductance in VLS growth mechanism.

In vitro activity of the new water-dispersible Fe3O4@usnic acid nanostructure against planktonic and sessile bacterial cells

NASA Astrophysics Data System (ADS)

Grumezescu, Alexandru Mihai; Cotar, Ani Ioana; Andronescu, Ecaterina; Ficai, Anton; Ghitulica, Cristina Daniela; Grumezescu, Valentina; Vasile, Bogdan Stefan; Chifiriuc, Mariana Carmen

2013-07-01

A new water-dispersible nanostructure based on magnetite (Fe3O4) and usnic acid (UA) was prepared in a well-shaped spherical form by a precipitation method. Nanoparticles were well individualized and homogeneous in size. The presence of Fe3O4@UA was confirmed by transmission electron microscopy, Fourier transform-infrared spectroscopy, and X-ray diffraction. The UA was entrapped in the magnetic nanoparticles during preparation and the amount of entrapped UA was estimated by thermogravimetric analysis. Fabricated nanostructures were tested on planktonic cells growth (minimal inhibitory concentration assay) and biofilm development on Gram-positive Staphylococcus aureus ( S. aureus), Enterococcus faecalis ( E. faecalis) and Gram-negative Escherichia coli ( E. coli), Pseudomonas aeruginosa (P. aeruginosa) reference strains. Concerning the influence of Fe3O4@UA on the planktonic bacterial cells, the functionalized magnetic nanoparticles exhibited a significantly improved antimicrobial activity against E. faecalis and E. coli, as compared with the Fe3O4 control. The UA incorporated into the magnetic nanoparticles exhibited a very significant inhibitory effect on the biofilm formed by the S. aureus and E. faecalis, on a wide range of concentrations, while in case of the Gram-negative microbial strains, the UA-loaded nanoparticles inhibited the E. coli biofilm development, only at high concentrations, while for P. aeruginosa biofilms, no inhibitory effect was observed. The obtained results demonstrate that the new water-dispersible Fe3O4@UA nanosystem, combining the advantages of the intrinsic antimicrobial features of the UA with the higher surface to volume ratio provided by the magnetic nanocarrier dispersible in water, exhibits efficient antimicrobial activity against planktonic and adherent cells, especially on Gram-positive strains.

Directed spatial organization of zinc oxide nanostructures

DOEpatents

Hsu, Julia [Albuquerque, NM; Liu, Jun [Richland, WA

2009-02-17

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

Fine-tunable plasma nano-machining for fabrication of 3D hollow nanostructures: SERS application

NASA Astrophysics Data System (ADS)

Mehrvar, L.; Hajihoseini, H.; Mahmoodi, H.; Tavassoli, S. H.; Fathipour, M.; Mohseni, S. M.

2017-08-01

Novel processing sequences for the fabrication of artificial nanostructures are in high demand for various applications. In this paper, we report on a fine-tunable nano-machining technique for the fabrication of 3D hollow nanostructures. This technique originates from redeposition effects occurring during Ar dry etching of nano-patterns. Different geometries of honeycomb, double ring, nanotube, cone and crescent arrays have been successfully fabricated from various metals such as Au, Ag, Pt and Ti. The geometrical parameters of the 3D hollow nanostructures can be straightforwardly controlled by tuning the discharge plasma pressure and power. The structure and morphology of nanostructures are probed using atomic force microscopy (AFM), scanning electron microscopy (SEM), optical emission spectroscopy (OES) and energy dispersive x-ray spectroscopy (EDS). Finally, a Ag nanotube array was assayed for application in surface enhanced Raman spectroscopy (SERS), resulting in an enhancement factor (EF) of 5.5 × 105, as an experimental validity proof consistent with the presented simulation framework. Furthermore, it was found that the theoretical EF value for the honeycomb array is in the order of 107, a hundred times greater than that found in nanotube array.

Nanostructured silicon ferromagnet collected by a permanent neodymium magnet.

PubMed

Okuno, Takahisa; Thürmer, Stephan; Kanoh, Hirofumi

2017-11-30

Nanostructured silicon (N-Si) was prepared by anodic electroetching of p-type silicon wafers. The obtained magnetic particles were separated by a permanent neodymium magnet as a magnetic nanostructured silicon (mN-Si). The N-Si and mN-Si exhibited different magnetic properties: the N-Si exhibited ferromagnetic-like behaviour, whereas the mN-Si exhibited superparamagnetic-like behaviour.

Layer-by-layer deposition of nanostructured CsPbBr3 perovskite thin films

NASA Astrophysics Data System (ADS)

Reshetnikova, A. A.; Matyushkin, L. B.; Andronov, A. A.; Sokolov, V. S.; Aleksandrova, O. A.; Moshnikov, V. A.

2017-11-01

Layer-by-layer deposition of nanostructured perovskites cesium lead halide thin films is described. The method of deposition is based on alternate immersion of the substrate in the precursor solutions or colloidal solution of nanocrystals and methyl acetate/lead nitrate solution using the device for deposition of films by SILAR and dip-coating techniques. An example of obtaining a photosensitive structure based on nanostructures of ZnO nanowires and layers of CsBbBr3 nanocrystals is also shown.

Fabrication of novel GMO/Eudragit E100 nanostructures for enhancing oral bioavailability of carvedilol.

PubMed

Patil, Sharvil S; Roy, Krishtey; Choudhary, Bhavana; Mahadik, Kakasaheb R

2016-08-01

In the present work, novel nanostructures comprising of glyceryl monooleate (GMO) and Eudragit E100 were prepared using high intensity ultrasonic homogenization. 3(2) Factorial design approach was used for optimization of nanostructures. Results of regression analysis revealed that the amount of GMO and Eudragit E100 had a drastic effect on particle size and percent entrapment efficiency. Optimized carvedilol-loaded nanostructures (Car-NS) were characterized by FTIR, TEM, DSC, in vitro drug release study. Pharmacokinetic parameters such as Cmax, Tmax, Ke, Ka, Vd and AUC were estimated for Car-NS upon its oral administration in Sprague-Dawley rats. Particle size of Car-NS was found to be 183 ± 2.43 nm with an entrapment efficiency of 81.4 ± 0.512%. FTIR studies revealed loading and chemical compatibility of carvedilol with the components of nanostructures. DSC thermograms did not show endothermic peak for melting of carvedilol which could be attributed to solubilization of carvedilol in molten GMO during DSC run. The prepared Car-NS released carvedilol in sustained manner over a period of 10 h as suggested by in vitro drug release study. The pharmacokinetic study of Car-NS showed significant improvement in Cmax (two fold, p < 0.001) and AUC (four folds, p < 0.001) of carvedilol when compared to carvedilol suspension. Car-NS were found to be stable for a period of 3 months. Thus, a stable, floating, multiparticulate GMO/Eudragit E100 nanostructures having ability to release the drug in sustained manner with enhanced oral bioavailability can prove to be a promising carrier system for poorly water soluble drugs.

Facile synthesis of one dimensional ZnO nanostructures for DSSC applications

NASA Astrophysics Data System (ADS)

Marimuthu, T.; Anandhan, N.

2016-05-01

Development of zinc oxide (ZnO) nanostructure based third generation dye sensitized solar cell is interesting compared to conventional silicon solar cells. ZnO nanostructured thin films were electrochemically deposited onto fluorine doped tin oxide (FTO) glass substrate. The effect of ethylene-diamine-tetra-acetic acid (EDTA) on structural, morphological and optical properties is investigated using X-ray diffraction (XRD) meter, field emission scanning electron microscope (FE-SEM) and micro Raman spectroscopy. XRD patterns reveal that the prepared nanostructures are hexagonal wutrzite structures with (101) plane orientation, the nanostructure prepared using EDTA exhibits better crystallinity. FE-SEM images illustrate that the morphological changes are observed from nanorod structure to cauliflower like structure as EDTA is added. Micro Raman spectra predict that cauliflower like structure possesses a higher crystalline nature with less atomic defects compared to nanorod structures. Dye sensitized solar cell (DSSC) is constructed for the optimized cauliflower structure, and open circuit voltage, short circuit density, fill factor and efficiency are estimated from the J-V curve.

Growth and Characterization of Nanostructured Glass Ceramic Scintillators for Miniature High-Energy Radiation Sensors

DTIC Science & Technology

2013-10-01

public release; distribution is unlimited. October 2013 HDTRA1-03-D-0009 Mansoor Sheik- Bahae Prepared by: OVPR...Characterization of Nanostructured Glass Ceramic Scintillators for Miniature High-Energy Radiation Sensors HDTRA01-03-D-0009 Mansoor Sheik- Bahae 26 OVPR...Table of Contents…………………………………………………………….3 I . Synthesis of Nano-Structured Glass Ceramic…..……………………………4 II. Characterize Structure and

Precise 3D printing of micro/nanostructures using highly conductive carbon nanotube-thiol-acrylate composites

NASA Astrophysics Data System (ADS)

Liu, Y.; Xiong, W.; Jiang, L. J.; Zhou, Y. S.; Lu, Y. F.

2016-04-01

Two-photon polymerization (TPP) is of increasing interest due to its unique combination of truly three-dimensional (3D) fabrication capability and ultrahigh spatial resolution of ~40 nm. However, the stringent requirements of non-linear resins seriously limit the material functionality of 3D printing via TPP. Precise fabrication of 3D micro/nanostructures with multi-functionalities such as high electrical conductivity and mechanical strength is still a long-standing challenge. In this work, TPP fabrication of arbitrary 3D micro/nanostructures using multi-walled carbon nanotube (MWNT)-thiolacrylate (MTA) composite resins has been developed. Up to 0.2 wt% MWNTs have been incorporated into thiol-acrylate resins to form highly stable and uniform composite photoresists without obvious degradation for one week at room temperature. Various functional 3D micro/nanostructures including woodpiles, micro-coils, spiral-like photonic crystals, suspended micro-bridges, micro-gears and complex micro-cars have been successfully fabricated. The MTA composite resin offers significant enhancements in electrical conductivity and mechanical strength, and on the same time, preserving high optical transmittance and flexibility. Tightly controlled alignment of MWNTs and the strong anisotropy effect were confirmed. Microelectronic devices including capacitors and resistors made of the MTA composite polymer were demonstrated. The 3D micro/nanofabrication using the MTA composite resins enables the precise 3D printing of micro/nanostructures of high electrical conductivity and mechanical strength, which is expected to lead a wide range of device applications, including micro/nano-electromechanical systems (MEMS/NEMS), integrated photonics and 3D electronics.

3D hollow nanostructures as building blocks for multifunctional plasmonics.

PubMed

De Angelis, Francesco; Malerba, Mario; Patrini, Maddalena; Miele, Ermanno; Das, Gobind; Toma, Andrea; Zaccaria, Remo Proietti; Di Fabrizio, Enzo

2013-08-14

We present an advanced and robust technology to realize 3D hollow plasmonic nanostructures which are tunable in size, shape, and layout. The presented architectures offer new and unconventional properties such as the realization of 3D plasmonic hollow nanocavities with high electric field confinement and enhancement, finely structured extinction profiles, and broad band optical absorption. The 3D nature of the devices can overcome intrinsic difficulties related to conventional architectures in a wide range of multidisciplinary applications.

Preparation of Hollow Fe2O3 Nanorods and Nanospheres by Nanoscale Kirkendall Diffusion, and Their Electrochemical Properties for Use in Lithium-Ion Batteries.

PubMed

Cho, Jung Sang; Park, Jin-Sung; Kang, Yun Chan

2016-12-13

A novel process for the preparation of aggregate-free metal oxide nanopowders with spherical (0D) and non-spherical (1D) hollow nanostructures was introduced. Carbon nanofibers embedded with iron selenide (FeSe) nanopowders with various nanostructures are prepared via the selenization of electrospun nanofibers. Ostwald ripening occurs during the selenization process, resulting in the formation of a FeSe-C composite nanofiber exhibiting a hierarchical structure. These nanofibers transform into aggregate-free hollow Fe 2 O 3 powders via the complete oxidation of FeSe and combustion of carbon. Indeed, the zero- (0D) and one-dimensional (1D) FeSe nanocrystals transform into the hollow-structured Fe 2 O 3 nanopowders via a nanoscale Kirkendall diffusion process, thus conserving their overall morphology. The discharge capacities for the 1000 th cycle of the hollow-structured Fe 2 O 3 nanopowders obtained from the FeSe-C composite nanofibers prepared at selenization temperatures of 500, 800, and 1000 °C at a current density of 1 A g -1 are 932, 767, and 544 mA h g -1 , respectively; and their capacity retentions from the second cycle are 88, 92, and 78%, respectively. The high structural stabilities of these hollow Fe 2 O 3 nanopowders during repeated lithium insertion/desertion processes result in superior lithium-ion storage performances.

Graphite nanoplatelets/multiwalled carbon nanotubes hybrid nanostructure for electrochemical capacitor.

PubMed

Mishra, Ashish Kumar; Ramaprabhu, S

2012-08-01

Recently, the focus on carbon based nanostructures for various applications has been due to their novel properties such as high electrical conductivity, high mechanical strength and high surface area. In the present work, we have investigated the charge storage capacity of modified graphite nanoplatelets and hybrid structure of graphite nanoplatelets-multiwalled carbon nanotubes (MWNTs). These MWNTs can be used as spacers to reduce the possibility of restacking of graphite nanoplatelets and hence increases the surface area of the hybrid carbon nanostructure thereby high degree of metal oxide decoration is achieved over the hybrid structure. MWNTs were prepared by catalytic chemical vapor deposition technique and further purified with air oxidation and acid treatment. Graphite was treated with conc. nitric acid and sulphuric acid in the volumetric ratio of 1:3 for 3 days and these modified graphite nanoplatelets were further stirred with MWNTs in equal weight ratio to form hybrid nanostructure. Further, ruthenium oxide (RuO2) nanoparticles were decorated on this hybrid structure using chemical route followed by calcination. RuO2 decorated hybrid carbon nanostructure was characterized by using X-ray diffraction, Electron microscopy and Raman spectroscopy. The performance of the hybrid structure based nanocomposite as electrochemical capacitor electrodes was analyzed by studing its capacitive and charge-discharge behaviours using cyclic voltammetry and chronopotentiometry techniques and the results have been discussed.

Insights into the enhanced photoelectrochemical performance of hydrothermally controlled hematite nanostructures for proficient solar water oxidation.

PubMed

Park, Jin Woo; Subramanian, Arunprabaharan; Mahadik, Mahadeo A; Lee, Su Yong; Choi, Sun Hee; Jang, Jum Suk

2018-03-28

In this paper, we focus on the controlled growth mechanism of α-Fe 2 O 3 nanostructures via the hydrothermal method. The field emission scanning electron microscopy (FESEM) results reveal that at a lower hydrothermal time, the initial nucleation involves the formation of short and thin β-FeOOH nanorods. The subsequent increase in the hydrothermal time leads β-FeOOH to form thicker and longer nanorods. However, high-temperature quenching (HTQ) at 800 °C for 10 min causes the conversion of akaganeite to the hematite phase and activation of hematite by Sn 4+ diffusion from a FTO substrate. Sn 4+ diffusion from the FTO substrate to the hematite nanostructure was elaborated by X-ray photoelectron spectroscopy (XPS). An α-Fe 2 O 3 nanorod photoanode prepared by a hydrothermal reaction for 3 h and HTQ exhibits the highest photocurrent density of 1.04 mA cm -2 . The excellent photoelectrochemical performance could be ascribed to the synergistic effect of the optimum growth of α-Fe 2 O 3 nanorod arrays and Sn 4+ diffusion. Intensity modulated photovoltage spectroscopy (IMVS) studies revealed that the α-Fe 2 O 3 photoanodes prepared at 3 h and HTQ exhibited a long electron lifetime (132.69 ms), and contribute to the enhanced PEC performance. The results confirmed that the controlled growth of the β-FeOOH nanorods, as well as Sn 4+ diffusion, played a key role in charge transfer during the photoelectrochemical application. The charge transfer mechanisms in α-Fe 2 O 3 nanostructure photoanodes prepared at different hydrothermal times and high-temperature quenching are also investigated.

Incredible antibacterial activity of noble metal functionalized magnetic core-zeolitic shell nanostructures.

PubMed

Padervand, M; Janatrostami, S; Karanji, A Kiani; Gholami, M R

2014-02-01

Functionalized magnetic core-zeolitic shell nanostructures were prepared by hydrothermal and coprecipitation methods. The products were characterized by Vibrating Sample Magnetometer (VSM), X-ray powder diffraction (XRD), Fourier Transform Infrared (FTIR) spectra, nitrogen adsorption-desorption isotherms, and Transmission Electron Microscopy (TEM). The growth of mordenite nanoparticles on the surface of silica coated nickel ferrite nanoparticles in the presence of organic templates was also confirmed. Antibacterial activity of the prepared nanostructures was investigated by the inactivation of Escherichia coli as a gram negative bacterium. A new mechanism was proposed for inactivation of E. coli over the prepared samples. In addition, the Minimum Inhibitory Concentration (MIC) and reuse ability were studied. TEM images of the destroyed cell wall after the treatment time were performed to illustrate the inactivation mechanism. According to the experimental results, the core-shell nanostructures which were modified by organic agents and then functionalized with noble metal nanoparticles were the most active. The interaction of the noble metals with the organic components on the surface of nanostructures was studied theoretically and the obtained results were used to interpret the experimental results. © 2013. Published by Elsevier B.V. All rights reserved.

Thermogravimetric and Magnetic Studies of the Oxidation and Reduction Reaction of SmCoO3 to Nanostructured Sm2O3 and Co

NASA Astrophysics Data System (ADS)

Kelly, Brian; Cichocki, Ronald; Poirier, Gerald; Unruh, Karl

The SmCoO3 to nanostructured Sm2O3 and Co oxidation and reduction reaction has been studied by thermogravimetric analysis (TGA) measurements in forming gas (FG) and inert N2 atmospheres, x-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The TGA measurements showed two clearly resolvable reduction processes when heating in FG, from the initial SmCoO3 phase through an intermediate nanostructured mixture of Sm2O3 and CoO when heated to 330°C for several minutes, and then the conversion of CoO to metallic Co when heated above 500°C. These phases were confirmed by XRD and VSM. Similar measurements in N2 yielded little mass change below 900°C and coupled reduction processes at higher temperatures. Isoconversional measurements of the CoO to Co reduction reaction in FG yielded activation energies above 2eV/atom in the nanostructured system. This value is several times larger than those reported in the literature or obtained by similar measurements of bulk mixtures of Sm2O3 and CoO, suggesting the nanostructuring was the source of the large increase in activation energy.

The role of cobalt doping on magnetic and optical properties of indium oxide nanostructured thin film prepared by sol–gel method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baqiah, H.; Ibrahim, N.B., E-mail: baayah@ukm.my; Halim, S.A.

2015-03-15

Highlights: • Cobalt doped indium oxide thin films have been prepared by a sol–gel method. • The films have a thickness less than 100 nm and grain size less than 10 nm. • The lattice parameters and grain size of films decrease as Co content increase. • The optical band gap of films increases as the grain size decrease. • The films' magnetic behaviour is sensitive to ratio of oxygen defects per Co ions. - Abstract: The effect of Co doping concentration, (x = 0.025–0.2), in In{sub 2−x}Co{sub x}O{sub 3} thin film was investigated by X-rays diffraction (XRD), transmission electronmore » microscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet visible spectrophotometer (UV–vis) and vibrating sample magnetometer (VSM). All films were prepared by sol–gel technique followed by spin coating process. The XRD and XPS measurements indicate that Co{sup +2} has been successfully substituted in In{sup +3} site. The TEM measurement shows nanostructure morphology of the films. The doping of Co in indium oxide resulted in a decrease in the lattice parameters and grain size while the band gap increased with increasing Co concentration. Further, by comparing VSM and XPS results, the magnetic behaviour of the films were found to be sensitive to Co concentrations, oxygen vacancies and ratio of oxygen defects to Co concentrations. The magnetic behaviour of the prepared films was explained using bound magnetic polaron (BMP) model.« less

Tapered Optical Fiber Probe Assembled with Plasmonic Nanostructures for Surface-Enhanced Raman Scattering Application.

PubMed

Huang, Zhulin; Lei, Xing; Liu, Ye; Wang, Zhiwei; Wang, Xiujuan; Wang, Zhaoming; Mao, Qinghe; Meng, Guowen

2015-08-12

Optical fiber-Raman devices integrated with plasmonic nanostructures have promising potentials for in situ probing remote liquid samples and biological samples. In this system, the fiber probe is required to simultaneously demonstrate stable surface enhanced Raman scattering (SERS) signals and high sensitivity toward the target species. Here we demonstrate a generic approach to integrate presynthesized plasmonic nanostructures with tapered fiber probes that are prepared by a dipping-etching method, through reversed electrostatic attraction between the silane couple agent modified silica fiber probe and the nanostructures. Using this approach, both negatively and positively charged plasmonic nanostructures with various morphologies (such as Au nanosphere, Ag nanocube, Au nanorod, Au@Ag core-shell nanorod) can be stably assembled on the tapered silica fiber probes. Attributed to the electrostatic force between the plasmonic units and the fiber surface, the nanostructures do not disperse in liquid samples easily, making the relative standard deviation of SERS signals as low as 2% in analyte solution. Importantly, the detection sensitivity of the system can be optimized by adjusting the cone angle (from 3.6° to 22°) and the morphology of nanostructures assembled on the fiber. Thus, the nanostructures-sensitized optical fiber-Raman probes show great potentials in the applications of SERS-based environmental detection of liquid samples.

Facile and Chemically Pure Preparation of YVO4:Eu3+ Colloid with Novel Nanostructure via Laser Ablation in Water

PubMed Central

Wang, Haohao; Odawara, Osamu; Wada, Hiroyuki

2016-01-01

A YVO4:Eu3+ colloid with an interesting nanostructure was formed by pulsed laser ablation in deionized water without any additives or surfactants. Analyses of particle morphology, composition and optical properties were accomplished by SEM, TEM, EDS PL and UV-vis. Ovoid-like particles formed by the agglomeration of numerous nanocrystals were observed by SEM and TEM, while EDS with area-mode analysis revealed that the content of dopant ion was well retained within the nanoparticles. In addition, the formation mechanism is deduced and discussed for the first time in this research. The findings of this study could provide new insights into the understanding of laser-induced oxide materials and offer an opportunity for other research groups to pursue red emitting nanophosphors with outstandingly purity. PMID:26842419

Thermal replacement reaction: a novel route for synthesizing eco-friendly ZnO@γ-In2Se3 hetero-nanostructures by replacing cadmium with indium and their photoelectrochemical and photocatalytic performances

NASA Astrophysics Data System (ADS)

Zhang, Zhuo; Choi, Mingi; Baek, Minki; Yong, Kijung

2015-05-01

A novel route called thermal replacement reaction was demonstrated for synthesizing eco-friendly ZnO@γ-In2Se3 hetero-structural nanowires on FTO glass by replacing the element cadmium with indium for the first time. The indium layer was coated on the surface of the ZnO nanowires beforehand, then CdSe quantum dots were deposited onto the coated indium layer, and finally the CdSe quantum dots were converted to γ-In2Se3 quantum dots by annealing under vacuum at 350 °C for one hour. The prepared ZnO@γ-In2Se3 hetero-nanostructures exhibit stable photoelectrochemical properties that can be ascribed to the protection of the In2O3 layer between the ZnO nanowire and γ-In2Se3 quantum dots and better photocatalytic performance in the wide wavelength region from 400 nm to nearly 750 nm. This strategy for preparing the ZnO@γ-In2Se3 hetero-nanostructures not only enriches our understanding of the single replacement reaction where the active element cadmium can be replaced with indium, but also opens a new way for the in situ conversion of cadmium-based to eco-friendly indium-based nano-devices.

Thermal replacement reaction: a novel route for synthesizing eco-friendly ZnO@γ-In2Se3 hetero-nanostructures by replacing cadmium with indium and their photoelectrochemical and photocatalytic performances.

PubMed

Zhang, Zhuo; Choi, Mingi; Baek, Minki; Yong, Kijung

2015-05-21

A novel route called thermal replacement reaction was demonstrated for synthesizing eco-friendly ZnO@γ-In2Se3 hetero-structural nanowires on FTO glass by replacing the element cadmium with indium for the first time. The indium layer was coated on the surface of the ZnO nanowires beforehand, then CdSe quantum dots were deposited onto the coated indium layer, and finally the CdSe quantum dots were converted to γ-In2Se3 quantum dots by annealing under vacuum at 350 °C for one hour. The prepared ZnO@γ-In2Se3 hetero-nanostructures exhibit stable photoelectrochemical properties that can be ascribed to the protection of the In2O3 layer between the ZnO nanowire and γ-In2Se3 quantum dots and better photocatalytic performance in the wide wavelength region from 400 nm to nearly 750 nm. This strategy for preparing the ZnO@γ-In2Se3 hetero-nanostructures not only enriches our understanding of the single replacement reaction where the active element cadmium can be replaced with indium, but also opens a new way for the in situ conversion of cadmium-based to eco-friendly indium-based nano-devices.

ZnO Nanostructures for Tissue Engineering Applications

PubMed Central

Laurenti, Marco; Cauda, Valentina

2017-01-01

This review focuses on the most recent applications of zinc oxide (ZnO) nanostructures for tissue engineering. ZnO is one of the most investigated metal oxides, thanks to its multifunctional properties coupled with the ease of preparing various morphologies, such as nanowires, nanorods, and nanoparticles. Most ZnO applications are based on its semiconducting, catalytic and piezoelectric properties. However, several works have highlighted that ZnO nanostructures may successfully promote the growth, proliferation and differentiation of several cell lines, in combination with the rise of promising antibacterial activities. In particular, osteogenesis and angiogenesis have been effectively demonstrated in numerous cases. Such peculiarities have been observed both for pure nanostructured ZnO scaffolds as well as for three-dimensional ZnO-based hybrid composite scaffolds, fabricated by additive manufacturing technologies. Therefore, all these findings suggest that ZnO nanostructures represent a powerful tool in promoting the acceleration of diverse biological processes, finally leading to the formation of new living tissue useful for organ repair. PMID:29113133

Intense ultraviolet emission from needle-like WO3 nanostructures synthesized by noncatalytic thermal evaporation

PubMed Central

2011-01-01

Photoluminescence measurements showed that needle-like tungsten oxide nanostructures synthesized at 590°C to 750°C by the thermal evaporation of WO3 nanopowders without the use of a catalyst had an intense near-ultraviolet (NUV) emission band that was different from that of the tungsten oxide nanostructures obtained in other temperature ranges. The intense NUV emission might be due to the localized states associated with oxygen vacancies and surface states. PMID:21752275

3D interconnected hierarchical porous N-doped carbon constructed by flake-like nanostructure with Fe/Fe3C for efficient oxygen reduction reaction and supercapacitor.

PubMed

Li, Guoning; Zhang, Jiajun; Li, Weisong; Fan, Kai; Xu, Chunjian

2018-05-17

Hierarchical porous N-doped carbon with Fe/Fe3C nanoparticles, high content of N dopants (10.51 wt%), and a 3D interconnected porous architecture constructed by flake-like nanostructure was facilely prepared by carbonization of a zeolitic imidazolate framework-8 (ZIF-8) as a self-sacrificing template and potassium ferricyanide (PF) as a multifunctional iron precursor. The unique porous structure can offer a continuous pathway for electron transfer and shorten the mass transfer pathway, which contribute to both an oxygen reduction reaction (ORR) and a supercapacitor. The influence of the carbonization temperature and iron content on the performance of ORR and supercapacitor was investigated. The as-prepared composites carbonized at 800 °C (Fe-CZIF-800-10) displayed comparable ORR activity with Pt/C in alkaline media as well as excellent long-term stability, superb methanol tolerance, and appreciable onset potential in acid media. Moreover, Fe-CZIF-800-10 exhibited excellent capacity of 246 F g-1 at a current density of 0.5 A g-1 and stability in 6 M KOH. This report provides a facile approach to prepare hierarchical porous Fe/N-doped carbon as a promising electrode material for both fuel cell and supercapacitor applications.

Chemistry and Processing of Nanostructured Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, G A; Baumann, T F; Hope-Weeks, L J

2002-01-18

Nanostructured materials can be formed through the sol-gel polymerization of inorganic or organic monomer systems. For example, a two step polymerization of tetramethoxysilane (TMOS) was developed such that silica aerogels with densities as low as 3 kg/m{sup 3} ({approx} two times the density of air) could be achieved. Organic aerogels based upon resorcinol-formaldehyde and melamine-formaldehyde can also be prepared using the sol-gel process. Materials of this type have received significant attention at LLNL due to their ultrafine cell sizes, continuous porosity, high surface area and low mass density. For both types of aerogels, sol-gel polymerization depends upon the transformation ofmore » these monomers into nanometer-sized clusters followed by cross-linking into a 3-dimensional gel network. While sol-gel chemistry provides the opportunity to synthesize new material compositions, it suffers from the inability to separate the process of cluster formation from gelation. This limitation results in structural deficiencies in the gel that impact the physical properties of the aerogel, xerogel or nanocomposite. In order to control the properties of the resultant gel, one should be able to regulate the formation of the clusters and their subsequent cross-linking. Towards this goal, we are utilizing dendrimer chemistry to separate the cluster formation from the gelation so that new nanostructured materials can be produced. Dendrimers are three-dimensional, highly branched macromolecules that are prepared in such a way that their size, shape and surface functionality are readily controlled. The dendrimers will be used as pre-formed clusters of known size that can be cross-linked to form an ordered gel network.« less

Effect of starting powders on the sintering of nanostructured ZrO2 ceramics by colloidal processing

NASA Astrophysics Data System (ADS)

Suárez, Gustavo; Sakka, Yoshio; Suzuki, Tohru S.; Uchikoshi, Tetsuo; Zhu, Xinwen; Aglietti, Esteban F.

2009-04-01

The effect of starting powders on the sintering of nanostructured tetragonal zirconia was evaluated. Suspensions were prepared with a concentration of 10 vol.% by mixing a bicomponent mixture of commercial powders (97 mol.% monoclinic zirconia with 3 mol.% yttria) and by dispersing commercially available tetragonal zirconia (3YTZ, Tosoh). The preparation of the slurry by bead-milling was optimized. Colloidal processing using 50 μm zirconia beads at 4000 rpm generated a fully deagglomerated suspension leading to the formation of high-density consolidated compacts (62% of the theoretical density (TD) for the bicomponent suspension). Optimum colloidal processing of the bicomponent suspension followed by the sintering of yttria and zirconia allowed us to obtain nanostructured tetragonal zirconia. Three different sintering techniques were investigated: normal sintering, two-step sintering and spark plasma sintering. The inhibition of grain growth in the bicomponent mixed powders in comparison with 3YTZ was demonstrated. The inhibition of the grain growth may have been caused by inter-diffusion of cations during the sintering.

Orienting proteins by nanostructured surfaces: evidence of a curvature-driven geometrical resonance.

PubMed

Messina, Grazia M L; Bocchinfuso, Gianfranco; Giamblanco, Nicoletta; Mazzuca, Claudia; Palleschi, Antonio; Marletta, Giovanni

2018-04-26

Experimental and theoretical reports have shown that nanostructured surfaces have a dramatic effect on the amount of protein adsorbed and the conformational state and, in turn, on the performances of the related devices in tissue engineering strategies. Here we report an innovative method to prepare silica-based nanostructured surfaces with a reproducible, well-defined local curvature, consisting of ordered hexagonally packed arrays of curved hemispheres, from nanoparticles of different diameters (respectively 147 nm, 235 nm and 403 nm). The nanostructured surfaces have been made chemically homogeneous by partially embedding silica nanoparticles in poly(hydroxymethylsiloxane) films, further modified by means of UV-O3 treatments. This paper has been focused on the experimental and theoretical study of laminin, taken as a model protein, to study the nanocurvature effects on the protein configuration at nanostructured surfaces. A simple model, based on the interplay of electrostatic interactions between the charged terminal domains of laminin and the nanocurved charged surfaces, closely reproduces the experimental findings. In particular, the model suggests that nanocurvature drives the orientation of rigid proteins by means of a "geometrical resonance" effect, involving the matching of dimensions, charge distribution and spatial arrangement of both adsorbed molecules and adsorbent nanostructures. Overall, the results pave the way to unravel the nanostructured surface effects on the intra- and inter-molecular organization processes of proteins.

Nanostructured Lipid Carriers Loaded with Baicalin: An Efficient Carrier for Enhanced Antidiabetic Effects.

PubMed

Shi, Feng; Wei, Zheng; Zhao, Yingying; Xu, Ximing

2016-01-01

Recent studies have demonstrated that baicalin has antihyperglycemic effects by inhibiting lipid peroxidation. Baicalin is low hydrophilic and poorly absorbed after oral administration. Thus, a suitable formulation is highly desired to overcome the disadvantages of baicalin. The objective of this work was to prepare baicalin-loaded nanostructured lipid carriers (B-NLCs) for enhanced antidiabetic effects. B-NLCs were prepared by high-pressure homogenization method using Precirol as the solid lipid and Miglyol as the liquid lipid. The properties of the NLCs, such as particle size, zeta potential (ZP), and drug encapsulation efficiency (EE), were investigated. The morphology of NLCs was observed by transmission electron microscopy. In addition, drug release and antidiabetic activity were also studied. The results revealed that B-NLCs particles were uniformly in the nanosize range and of spherical morphology with a mean size of 92 ± 3.1 nm, a ZP of -31.35 ± 3.08 mV, and an EE of 85.29 ± 3.42%. Baicalin was released from NLCs in a sustained manner. In addition, B-NLCs showed a significantly higher antidiabetic efficacy compared with baicalin. B-NLCs described in this study are well-suited for the delivery of baicalin. Currently, herbal medicines have attracted increasing attention as a complementary approach for type 2 diabetesBaicalin has antihyperglycemic effects by inhibiting lipid peroxidationA suitable formulation is highly desired to overcome the disadvantages (poor solubility and low bioavailability) of baicalinNanostructured lipid carriers could enhance the antidiabetic effects of baicalin. Abbreviations used: B-NLCs: Baicalin-Loaded Nanostructured Lipid Carriers, B-SUS: Baicalin Water Suspension, EE: Encapsulation Efficiency, FBG: Fasting Blood Glucose, HbAlc: Glycosylated Hemoglobin, HPLC: High-performance Liquid Chromatography; NLCs: Nanostructured Lipid Carriers, PI: Polydispersity Index, SD: Sprague-Dawley, SLNs: Solid lipid nanoparticles, STZ

A biotemplated nickel nanostructure: Synthesis, characterization and antibacterial activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashtari, Khadijeh; Fasihi, Javad; Mollania, Nasrin

Highlights: • Nickel nanostructure-encapsulated bacteria were prepared using electroless deposition. • Bacterium surface was activated by red-ox reaction of its surface amino acids. • Interfacial changes at cell surfaces were investigated using fluorescence spectroscopy. • TEM and AFM depicted morphological changes. • Antibacterial activity of nanostructure was examined against different bacteria strains. - Abstract: Nickel nanostructure-encapsulated bacteria were prepared using the electroless deposition procedure and activation of bacterium cell surface by red-ox reaction of surface amino acids. The electroless deposition step occurred in the presence of Ni(II) and dimethyl amine boran (DMAB). Interfacial changes at bacteria cell surfaces during themore » coating process were investigated using fluorescence spectroscopy. Fluorescence of tryptophan residues was completely quenched after the deposition of nickel onto bacteria surfaces. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) depicted morphological changes on the surface of the bacterium. It was found that the Ni coated nanostructure was mechanically stable after ultrasonication for 20 min. Significant increase in surface roughness of bacteria was also observed after deposition of Ni clusters. The amount of coated Ni on the bacteria surface was calculated as 36% w/w. The antibacterial activity of fabricated nanostructure in culture media was examined against three different bacteria strains; Escherichia coli, Bacillus subtilis and Xantomonas campestris. The minimum inhibitory concentrations (MIC) were determined as 500 mg/L, 350 mg/L and 200 mg/L against bacteria, respectively.« less

Temperature dependence of Ni3S2 nanostructures with high electrochemical performance

NASA Astrophysics Data System (ADS)

Wang, Y. L.; Wei, X. Q.; Li, M. B.; Hou, P. Y.; Xu, X. J.

2018-04-01

Different Ni3S2 nanostructures have been successfully synthesized at different temperatures by a facile and efficient solvothermal method. The Ni3S2 nanostructures with three-dimensional (3D) nanosheets array and silkworm eggs-like morphologies were obtained by adjusting the reaction temperature. A large number of 3D nanosheets are interconnected to form an open network structure with porous of Ni3S2 at 180 °C, and electrochemical tests showed that the special structure exhibited the outstanding specific capacitance (1357 F g -1 at 1 A g-1) and excellent cycling stability (maintained 91% after 3000 cycles). In comparison, the performance of Ni3S2 silkworm eggs-like structure is not very perfect. This may be due to the fact that the 3D nanosheets with porous structure can improve the electrochemical performance by shortening effectively the diffusion path of electrolyte ions and increasing the active sites during charging and discharging. Among them, the reaction temperature is the main factor to control the formation of the 3D nanosheets array. These results indicated the Ni3S2 nanosheets promising applications as high-performance supercapacitor electrode materials.

Tellurium nano-structure based NO gas sensor.

PubMed

Kumar, Vivek; Sen, Shashwati; Sharma, M; Muthe, K P; Jagannath; Gaur, N K; Gupta, S K

2009-09-01

Tellurium nanotubes were grown on bare and silver/gold nanoparticle (nucleation centers) deposited silicon substrates by vacuum deposition technique at a substrate temperature of 100 degrees C under high vacuum conditions. Silver and gold nanoparticles prepared on (111) oriented silicon substrates were found to act as nucleation centers for growth of Tellurium nanostructures. Density of nanotubes was found to increase while their diameter reduced when grown using metallic nanoparticle template. These Te nanostructures were investigated for their gas sensitivity. Tellurium nanotubes on Ag templates showed better response to NO in comparison to H2S and NH3 gases. Selectivity in response to NO was improved in comparison to Te thin film sensors reported earlier. The gas sensing mechanism was investigated using Raman and X-ray photoelectron spectroscopy techniques. The interaction of NO is seen to yield increased adsorption of oxygen that in turn increases hole density and conductivity in the material.

Dopant concentration dependent growth of Fe:ZnO nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahai, Anshuman; Goswami, Navendu, E-mail: navendugoswami@gmail.com

2016-05-23

Systematic investigations of structural properties of 1-10% Fe doped ZnO nanostructure (Fe:ZnO NS) prepared via chemical precipitation method have been reported. Structural properties were probed thoroughly employing scanning electron microscope (SEM) and transmission electron microscope (TEM), energy dispersive X-ray (EDAX) analysis and X-ray diffraction (XRD). Morphological transformation of nanostructures (NS) with Fe incorporation is evident in SEM/TEM images. Nanoparticles (NP) obtained with 1% Fe, evolve to nanorods (NR) for 3% Fe; NR transform to nanocones (NC) (for 5% and 7% Fe) and finally NC transform to nanoflakes (NF) at 10% Fe. Morover, primary phase of Zn{sub 1-x}Fe{sub x}O along withmore » secondary phases of ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3} were also revealed through XRD measurements. Based on collective XRD, SEM, TEM, and EDAX interpretations, a model for morphological evolution of NS was proposed and the pivotal role of Fe dopant was deciphered.« less

Preparation of cauliflower-like CdS/ZnS/ZnO nanostructure and its photoelectric properties

NASA Astrophysics Data System (ADS)

Liu, Zhifeng; Guo, Keying; Wang, Yun; Zheng, Xuerong; Ya, Jing; Li, Junwei; Han, Li; Liu, Zhichao; Han, Jianhua

2014-06-01

Cauliflower-like CdS/ZnS/ZnO nanostructure is fabricated via a simple hydrothermal method. Factors such as concentration of reaction solution, reaction temperature, as well as reaction time in the synthetic process are investigated, and the working mechanism of the nanostructure is suggested. Hydrogen generation efficiency of 4.69 % at 0.29 V versus saturated calomel electrode is achieved using synthesized nanostructure as electrode due to the improved absorption and appropriate energy gap structure, which is confirmed by enhanced absorption spectrum. The expected products have potential application in photoelectrochemical water splitting.

Photoelectrochemical Water Splitting Properties of Ti-Ni-Si-O Nanostructures on Ti-Ni-Si Alloy

PubMed Central

Dong, Zhenbiao; Ning, Congqin

2017-01-01

Ti-Ni-Si-O nanostructures were successfully prepared on Ti-1Ni-5Si alloy foils via electrochemical anodization in ethylene glycol/glycerol solutions containing a small amount of water. The Ti-Ni-Si-O nanostructures were characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and diffuse reflectance absorption spectra. Furthermore, the photoelectrochemical water splitting properties of the Ti-Ni-Si-O nanostructure films were investigated. It was found that, after anodization, three different kinds of Ti-Ni-Si-O nanostructures formed in the α-Ti phase region, Ti2Ni phase region, and Ti5Si3 phase region of the alloy surface. Both the anatase and rutile phases of Ti-Ni-Si-O oxide appeared after annealing at 500 °C for 2 h. The photocurrent density obtained from the Ti-Ni-Si-O nanostructure photoanodes was 0.45 mA/cm2 at 0 V (vs. Ag/AgCl) in 1 M KOH solution. The above findings make it feasible to further explore excellent photoelectrochemical properties of the nanostructure-modified surface of Ti-Ni-Si ternary alloys. PMID:29088083

Mesoporous wormholelike carbon with controllable nanostructure for lithium ion batteries application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xiaoqing, E-mail: yxq-886@163.com; Li, Xinxi; Li, Zhenghui

2015-06-15

Highlights: • Wormholelike carbon (WMC) with controllable nanostructure is prepared by sol–gel method. • The reversible capacity of WMC is much higher than that of many other reported nanocarbons. • The effect of pore diameter on Li storage capacity is investigated. - Abstract: A class of mesoporous wormholelike carbon (WMC) with controllable nanostructure was prepared by sol–gel method and then used as the anode material of lithium-ion batteries. Based on the experimental results, it is found that the nanostructure of the as-prepared WMC plays an important role in the electrochemical performances. A suitable mesopore size is necessary for a highmore » performance carbon-based anode material since it can not only guarantee effective mass transport channels but also provide large surface area. As a result, F30 with a mesopore size of 4.4 nm coupled with high surface area of 1077 m{sup 2} g{sup −1} shows a reversible capacity of 630 mAh g{sup −1}, much higher than commercial graphite and many other reported nanocarbons.« less

Fabrication of nanostructured ZnO film as a hole-conducting layer of organic photovoltaic cell

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Kwon, Yiseul; Choe, Youngson

2013-05-01

We have investigated the effect of fibrous nanostructured ZnO film as a hole-conducting layer on the performance of polymer photovoltaic cells. By increasing the concentration of zinc acetate dihydrate, the changes of performance characteristics were evaluated. Fibrous nanostructured ZnO film was prepared by sol-gel process and annealed on a hot plate. As the concentration of zinc acetate dihydrate increased, ZnO fibrous nanostructure grew from 300 to 600 nm. The obtained ZnO nanostructured fibrous films have taken the shape of a maze-like structure and were characterized by UV-visible absorption, scanning electron microscopy, and X-ray diffraction techniques. The intensity of absorption bands in the ultraviolet region was increased with increasing precursor concentration. The X-ray diffraction studies show that the ZnO fibrous nanostructures became strongly (002)-oriented with increasing concentration of precursor. The bulk heterojunction photovoltaic cells were fabricated using poly(3-hexylthiophene-2,5-diyl) and indene-C60 bisadduct as active layer, and their electrical properties were investigated. The external quantum efficiency of the fabricated device increased with increasing precursor concentration.

Fabrication of nanostructured ZnO film as a hole-conducting layer of organic photovoltaic cell

PubMed Central

2013-01-01

We have investigated the effect of fibrous nanostructured ZnO film as a hole-conducting layer on the performance of polymer photovoltaic cells. By increasing the concentration of zinc acetate dihydrate, the changes of performance characteristics were evaluated. Fibrous nanostructured ZnO film was prepared by sol-gel process and annealed on a hot plate. As the concentration of zinc acetate dihydrate increased, ZnO fibrous nanostructure grew from 300 to 600 nm. The obtained ZnO nanostructured fibrous films have taken the shape of a maze-like structure and were characterized by UV-visible absorption, scanning electron microscopy, and X-ray diffraction techniques. The intensity of absorption bands in the ultraviolet region was increased with increasing precursor concentration. The X-ray diffraction studies show that the ZnO fibrous nanostructures became strongly (002)-oriented with increasing concentration of precursor. The bulk heterojunction photovoltaic cells were fabricated using poly(3-hexylthiophene-2,5-diyl) and indene-C60 bisadduct as active layer, and their electrical properties were investigated. The external quantum efficiency of the fabricated device increased with increasing precursor concentration. PMID:23680100

Cathodoluminescence of rare earth implanted Ga2O3 and GeO2 nanostructures.

PubMed

Nogales, E; Hidalgo, P; Lorenz, K; Méndez, B; Piqueras, J; Alves, E

2011-07-15

Rare earth (RE) doped gallium oxide and germanium oxide micro- and nanostructures, mostly nanowires, have been obtained and their morphological and optical properties have been characterized. Undoped oxide micro- and nanostructures were grown by a thermal evaporation method and were subsequently doped with gadolinium or europium ions by ion implantation. No significant changes in the morphologies of the nanostructures were observed after ion implantation and thermal annealing. The luminescence emission properties have been studied with cathodoluminescence (CL) in a scanning electron microscope (SEM). Both β-Ga(2)O(3) and GeO(2) structures implanted with Eu show the characteristic red luminescence peak centered at around 610 nm, due to the (5)D(0)-(7)F(2) Eu(3+) intraionic transition. Sharpening of the luminescence peaks after thermal annealing is observed in Eu implanted β-Ga(2)O(3), which is assigned to the lattice recovery. Gd(3+) as-implanted samples do not show rare earth related luminescence. After annealing, optical activation of Gd(3+) is obtained in both matrices and a sharp ultraviolet peak centered at around 315 nm, associated with the Gd(3+) (6)P(7/2)-(8)S(7/2) intraionic transition, is observed. The influence of the Gd ion implantation and the annealing temperature on the gallium oxide broad intrinsic defect band has been analyzed.

A 3D insight on the catalytic nanostructuration of few-layer graphene

NASA Astrophysics Data System (ADS)

Melinte, G.; Florea, I.; Moldovan, S.; Janowska, I.; Baaziz, W.; Arenal, R.; Wisnet, A.; Scheu, C.; Begin-Colin, S.; Begin, D.; Pham-Huu, C.; Ersen, O.

2014-06-01

The catalytic cutting of few-layer graphene is nowadays a hot topic in materials research due to its potential applications in the catalysis field and the graphene nanoribbons fabrication. We show here a 3D analysis of the nanostructuration of few-layer graphene by iron-based nanoparticles under hydrogen flow. The nanoparticles located at the edges or attached to the steps on the FLG sheets create trenches and tunnels with orientations, lengths and morphologies defined by the crystallography and the topography of the carbon substrate. The cross-sectional analysis of the 3D volumes highlights the role of the active nanoparticle identity on the trench size and shape, with emphasis on the topographical stability of the basal planes within the resulting trenches and channels, no matter the obstacle encountered. The actual study gives a deep insight on the impact of nanoparticles morphology and support topography on the 3D character of nanostructures built up by catalytic cutting.

Effect of Ga incorporation on morphology and defect structures evolution in VLS grown 1D In2O3 nanostructures

NASA Astrophysics Data System (ADS)

Ramos-Ramón, Jesús Alberto; Pal, Umapada; Cremades, Ana; Maestre, David

2018-05-01

Fabrication of 1D metal oxide nanostructures of controlled morphology and defect structure is of immense importance for their application in optoelectronics. While the morphology of these nanostructures depends primarily on growth parameters utilized in physical deposition processes, incorporation of foreign elements or dopants not only affects their morphology, but also affects their crystallinity and defect structure, which are the most important parameters for their device applications. Herein we report on the growth of highly crystalline 1D In2O3 nanostructures through vapor-liquid-solid process at relatively low temperature, and the effect of Ga incorporation on their morphology and defect structures. Through electron microscopy, Raman spectroscopy and cathodoluminescence spectroscopy techniques, we demonstrate that incorporation of Ga in In2O3 nanostructures not only strongly affects their morphology, but also generates new defect levels in the band gap of In2O3, shifting the overall emission of the nanostructures towards visible spectral range.

Photochemical decoration of magnetic composites with silver nanostructures for determination of creatinine in urine by surface-enhanced Raman spectroscopy.

PubMed

Alula, Melisew Tadele; Yang, Jyisy

2014-12-01

In this study, silver nanostructures decorated magnetic nanoparticles for surface-enhanced Raman scattering (SERS) measurements were prepared via photoreduction utilizing the catalytic activity of ZnO nanostructure. The ZnO/Fe3O4 composite was first prepared by dispersing pre-formed magnetic nanoparticles into alkaline zinc nitrate solutions. After annealing of the precipitates, the formed ZnO/Fe3O4 composites were successfully decorated with silver nanostructures by soaking the composites into silver nitrate/ethylene glycol solution following UV irradiations. To find the optimal condition when preparing Ag@ZnO/Fe3O4 composites for SERS measurements, factors such as the reaction conditions, photoreduction time, concentration of zinc nitrate and silver nitrate were studied. Results indicated that the photoreduction efficiency was significantly improved with the assistance of ZnO but the amount of ZnO in the composite is not critical. The concentration of silver nitrate and UV irradiation time affected the morphologies of the formed composites and optimal condition in preparation of the composites for SERS measurement was found using 20mM of silver nitrate with an irradiation time of 90 min. Under the optimized condition, the obtained SERS intensities were highly reproducible with a SERS enhancement factor in the order of 7. Quantitative analyses showed that a linear range up to 1 µM with a detection limit lower than 0.1 µM in the detection of creatinine in aqueous solution could be obtained. Successful applying of these prepared composites to determine creatinine in urine sample was obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

Simple method for preparation of nanostructurally organized spines of sand dollar Scaphechinus mirabilis (Agassiz, 1863).

PubMed

Ehrlich, Herman; Elkin, Yury N; Artoukov, Alexandr A; Stonik, Valentin A; Safronov, Peter P; Bazhenov, Vasily V; Kurek, Denis V; Varlamov, Valery P; Born, René; Meissner, Heike; Richter, Gert

2011-06-01

Unique skeletal formations of marine invertebrates, including representatives of Echinodermata, have the unique potential to serve as templates for bio-inspired materials chemistry, biomimetics, and materials science. The sand dollar Scaphechinus mirabilis (Agassiz, 1983) is widely distributed in the northwest of the Pacific Ocean from southern Japan to the Aleutian Islands. This animal is the main source of naphtochinone-based substances. These compounds have recently drawn medical attention for their use as cardiological and ophthalmological drugs. Unfortunately, after extraction of the naphtochinones, the residual skeletons and spines of the sand dollars were usually discarded. Here, we report the first method for the preparation of nanostructurally organized spines of S. mirabilis, using a simple enzymatic and hydrogen peroxide-based treatment. Application of this method opens the way for development of non-wasteful environmentally clean technology of sand dollars as well-known industrial marine invertebrates.

Studies on structural and electrical properties of nanostructured RMnO3 (R = Gd & Ho)

NASA Astrophysics Data System (ADS)

Sapana, Solanki; Dhruv, Davit; Joshi, Zalak; Gadani, Keval; Rathod, K. N.; Boricha, Hetal; Shrimali, V. G.; Trivedi, R. K.; Joshi, A. D.; Pandya, D. D.; Solanki, P. S.; Shah, N. A.

2017-05-01

We report the results of the studies on the structural and electrical properties of multiferroic GdMnO3 and HoMnO3 materials synthesized by sol-gel route. Structural analysis of the results of X-ray diffraction (XRD) measurement shows that materials are found to be crystallized in orthorhombic and hexagonal symmetry, respectively for GdMnO3 and HoMnO3. Frequency dependent dielectric properties of nanostructured GdMnO3 and HoMnO3 were carried out using LCR meter in the frequency range of 100Hz to 2MHz at room temperature. Dielectric constant decreases with increasing frequency for both the nanostructured multiferroics which can be attributed to the dipole relaxation process. AC conductivity (σAC) has been measured for both the samples and fitted theoretically by using power law equation.

Comparison of structural and optical properties of TeO2 nanostructures synthesized using various substrate conditions

NASA Astrophysics Data System (ADS)

Jung, Taek-Kyun; Ryou, Min; Lee, Ji-Woon; Hyun, Soong-Keun; Na, Han Gil; Jin, Changhyun

2017-11-01

Several TeO2 low-dimensional nanostructures were prepared by thermal evaporation using four substrate conditions: (1) a bare substrate, (2) a scratched substrate, (3) a Au-catalyst-assisted substrate, and (4) a multi-walled carbon nanotube (MWCNT)-assisted substrate. Scanning electron microscopy and transmission electron microscopy analysis reveals that the morphologies of the nanostructures synthesized using these methods gradually changed from nanoparticles to ultra-thin nanowires with single tetragonal-type TeO2. Photoluminescence (PL) spectra reveal that the PL intensities of the TeO2 nanomaterials obtained using methods (1) and (2) are slightly increased, whereas the intensities of the TeO2 nanostructures obtained using methods (3) and (4) differ significantly depending on the initial substrate conditions. The emission peak is also blue-shifted from 440 nm to 430 nm for the scratched surface condition due to an excitonic transition. The increase in the blue emission for the MWCNT-assisted condition is attributed to the degree and type of excitons and defects in the TeO2 nanostructures.

Enzymatic Synthesis of Self-assembled Dicer Substrate RNA Nanostructures for Programmable Gene Silencing.

PubMed

Jang, Bora; Kim, Boyoung; Kim, Hyunsook; Kwon, Hyokyoung; Kim, Minjeong; Seo, Yunmi; Colas, Marion; Jeong, Hansaem; Jeong, Eun Hye; Lee, Kyuri; Lee, Hyukjin

2018-06-08

Enzymatic synthesis of RNA nanostructures is achieved by isothermal rolling circle transcription (RCT). Each arm of RNA nanostructures provides a functional role of Dicer substrate RNA inducing sequence specific RNA interference (RNAi). Three different RNAi sequences (GFP, RFP, and BFP) are incorporated within the three-arm junction RNA nanostructures (Y-RNA). The template and helper DNA strands are designed for the large-scale in vitro synthesis of RNA strands to prepare self-assembled Y-RNA. Interestingly, Dicer processing of Y-RNA is highly influenced by its physical structure and different gene silencing activity is achieved depending on its arm length and overhang. In addition, enzymatic synthesis allows the preparation of various Y-RNA structures using a single DNA template offering on demand regulation of multiple target genes.

Fabrication of three-dimensional hybrid nanostructure-embedded ITO and its application as a transparent electrode for high-efficiency solution processable organic photovoltaic devices.

PubMed

Kim, Jeong Won; Jeon, Hwan-Jin; Lee, Chang-Lyoul; Ahn, Chi Won

2017-03-02

Well-aligned, high-resolution (10 nm), three-dimensional (3D) hybrid nanostructures consisting of patterned cylinders and Au islands were fabricated on ITO substrates using an ion bombardment process and a tilted deposition process. The fabricated 3D hybrid nanostructure-embedded ITO maintained its excellent electrical and optical properties after applying a surface-structuring process. The solution processable organic photovoltaic device (SP-OPV) employing a 3D hybrid nanostructure-embedded ITO as the anode displayed a 10% enhancement in the photovoltaic performance compared to the photovoltaic device prepared using a flat ITO electrode, due to the improved charge collection (extraction and transport) efficiency as well as light absorbance by the photo-active layer.

Influence of Doping and Nanostructuration on n-Type Bi2(Te0.8Se0.2)3 Alloys Synthesized by Arc Melting

NASA Astrophysics Data System (ADS)

Gharsallah, Mouna; Serrano-Sanchez, Federico; Nemes, Norbert M.; Martinez, Jose Luis; Alonso, Jose Antonio

2017-01-01

In competitive thermoelectric devices for energy conversion and generation, high-efficiency materials of both n-type and p-type are required. For this, Bi2Te3-based alloys have the best thermoelectric properties in room temperature applications. Partial replacement of tellurium by selenium is expected to introduce new donor states in the band gap, which would alter electrical conductivity and thermopower. We report on the preparation of n-type Bi2(Te1-xSex)3 solid solutions by a straightforward arc-melting technique, yielding nanostructured polycrystalline pellets. X-ray and neutron powder diffraction was used to assess Se inclusion, also indicating that the interactions between quintuple layers constituting this material are weakened upon Se doping, while the covalency of intralayer bonds is augmented. Moreover, scanning electron microscopy shows large surfaces perpendicular to the c crystallographic axis assembled as stacked sheets. Grain boundaries related to this 2D nanostructuration affect the thermal conductivity reducing it below 0.8 Wm-1K-1 at room temperature. Furthermore, Se doping increases the absolute Seebeck coefficient up to -140 μV K-1 at 400 K, which is also beneficial for improved thermoelectric efficiency.

Characterisation of 3D-GaN/InGaN nanostructured Light Emitting Diodes by Transmission Electron Microscopy

NASA Astrophysics Data System (ADS)

Griffiths, I. J.; Cherns, D.; Wang, X.; Waag, A.; Wehmann, H.-H.

2013-11-01

Transmission and scanning electron microscopy have been used to characterise GaN/InGaN 3D nanostructures grown on patterned GaN/sapphire substrates by MOVPE. It has been found that the growth of well ordered arrays of such nanostructures, containing multiple quantum wells on non-polar side-facets, can be achieved with a low density of defects. Growth changes and surface morphology play a major role in the nucleation of any defects present. The nanostructure morphology has been investigated and non-uniform growth on adjacent facets studied.

Nanostructural Tailoring to Induce Flexibility in Thermoelectric Ca3Co4O9 Thin Films

PubMed Central

2017-01-01

Because of their inherent rigidity and brittleness, inorganic materials have seen limited use in flexible thermoelectric applications. On the other hand, for high output power density and stability, the use of inorganic materials is required. Here, we demonstrate a concept of fully inorganic flexible thermoelectric thin films with Ca3Co4O9-on-mica. Ca3Co4O9 is promising not only because of its high Seebeck coefficient and good electrical conductivity but also because of the abundance, low cost, and nontoxicity of its constituent raw materials. We show a promising nanostructural tailoring approach to induce flexibility in inorganic thin-film materials, achieving flexibility in nanostructured Ca3Co4O9 thin films. The films were grown by thermally induced phase transformation from CaO–CoO thin films deposited by reactive rf-magnetron cosputtering from metallic targets of Ca and Co to the final phase of Ca3Co4O9 on a mica substrate. The pattern of nanostructural evolution during the solid-state phase transformation is determined by the surface energy and strain energy contributions, whereas different distributions of CaO and CoO phases in the as-deposited films promote different nanostructuring during the phase transformation. Another interesting fact is that the Ca3Co4O9 film is transferable onto an arbitrary flexible platform from the parent mica substrate by etch-free dry transfer. The highest thermoelectric power factor obtained is above 1 × 10–4 W m–1 K–2 in a wide temperature range, thus showing low-temperature applicability of this class of materials. PMID:28699345

Synthesis of In2O3 nanostructures with different morphologies as potential supercapacitor electrode materials

NASA Astrophysics Data System (ADS)

Tuzluca, Fatma Nur; Yesilbag, Yasar Ozkan; Ertugrul, Mehmet

2018-01-01

In this study performed using a chemical vapor deposition (CVD) system, one-dimensional (1-D) single crystal indium oxide (In2O3) nanotowers, nanobouqets, nanocones, and nanowires were investigated as a candidate for a supercapacitor electrode material. These nanostructures were grown via Vapor-Liquid-Solid (VLS) and Vapor-Solid (VS) mechanisms according to temperature differences (1000-600 °C). The morphologies, growth mechanisms and crystal structures of these 1-D single crystal In2O3 nanostructures were defined by Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HR-TEM), X-Ray Diffraction (XRD) and Raman Spectroscopy analyses. The elemental analyses of the nanostructures were carried out by energy dispersive X-Ray Spectroscopy (EDS); they gave photoluminescence (PL) spectra with 3.39, 2.65, and 1.95 eV band gap values, corresponding to 365 nm, 467 nm, and 633 wavelengths, respectively. The electrochemical performances of these 1-D single crystal In2O3 nanostructures in an aqueous electrolyte solution (1 M Na2SO4) were determined by Cyclic Voltammetry (CV), Galvanostatic Charge Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) analyses. According to GCD measurements at 0.04 mA cm-2 current density, areal capacitance values were 10.1 mF cm-2 and 6.7 mF cm-2 for nanotowers, 12.5 mF cm-2 for nanobouquets, 4.9 mF cm-2 for nanocones, and 16.6 mF cm-2 for nanowires. The highest areal capacitance value was observed in In2O3 nanowires, which retained 66.8% of their initial areal capacitance after a 10000 charge-discharge cycle, indicating excellent cycle stability.

Controlled synthesis of different metal oxide nanostructures by direct current arc discharge.

PubMed

Su, Yanjie; Zhang, Jing; Zhang, Liling; Zhang, Yafei

2013-02-01

Direct current (DC) arc discharge method gives high temperature in a short time, which has been widely used to prepare carbon nanotubes. We use this simple approach to synthesize metal oxide nanostructures (MgO, SnO2) without any catalyst. Different morphologies (nanowires, nanobelts, nanocubes, and nanodisks) of metal oxide nanostructures can be controllably synthesized by changing the content of air in buffer gas. The growth mechanisms for these nanostructures are discussed in detail. Oxygen partial pressure is supposed to be one of the most important key factors. The methodology might be used to synthesize similar nanostructures of other functional oxide materials and non-oxide materials.

Synthesis and antimicrobial activity of gold/silver-tellurium nanostructures.

PubMed

Chang, Hsiang-Yu; Cang, Jinshun; Roy, Prathik; Chang, Huan-Tsung; Huang, Yi-Cheng; Huang, Chih-Ching

2014-06-11

Gold-tellurium nanostructures (Au-Te NSs), silver-tellurium nanostructures (Ag-Te NSs), and gold/silver-tellurium nanostructures (Au/Ag-Te NSs) have been prepared through galvanic reactions of tellurium nanotubes (Te NTs) with Au(3+), Ag(+), and both ions, respectively. Unlike the use of less environmentally friendly hydrazine, fructose as a reducing agent has been used to prepare Te NTs from TeO2 powders under alkaline conditions. The Au/Ag-Te NSs have highly catlaytic activity to convert nonfluorescent Amplex Red to form fluorescent product, revealing their great strength of generating reactive oxygen species (ROS). Au/Ag-Te NSs relative to the other two NSs exhibit greater antimicrobial activity toward the growth of E. coli, S. enteritidis, and S. aureus; the minimal inhibitory concentration (MIC) values of Au/Ag-Te NSs were much lower (>10-fold) than that of Ag-Te NSs and Au-Te NSs. The antibacterial activity of Au/Ag-Te NSs is mainly due to the release of Ag(+) ions and Te-related ions and also may be due to the generated ROS which destroys the bacteria membrane. In vitro cytotoxicity and hemolysis analyses have revealed their low toxicity in selected human cell lines and insignificant hemolysis in red blood cells. In addition, inhibition zone measurements using a Au/Ag-Te NSs-loaded konjac jelly film have suggested that it has great potential in practial application such as wound dressing for reducing bacterial wound infection. Having great antibacterial activitiy and excellent biocompatibility, the low-cost Au/Ag-Te NSs hold great potential as effective antimicrobial drugs.

Fabrication of 3D nano-structures using reverse imprint lithography

NASA Astrophysics Data System (ADS)

Han, Kang-Soo; Hong, Sung-Hoon; Kim, Kang-In; Cho, Joong-Yeon; Choi, Kyung-woo; Lee, Heon

2013-02-01

In spite of the fact that the fabrication process of three-dimensional nano-structures is complicated and expensive, it can be applied to a range of devices to increase their efficiency and sensitivity. Simple and inexpensive fabrication of three-dimensional nano-structures is necessary. In this study, reverse imprint lithography (RIL) with UV-curable benzylmethacrylate, methacryloxypropyl terminated poly-dimethylsiloxane (M-PDMS) resin and ZnO-nano-particle-dispersed resin was used to fabricate three-dimensional nano-structures. UV-curable resins were placed between a silicon stamp and a PVA transfer template, followed by a UV curing process. Then, the silicon stamp was detached and a 2D pattern layer was transferred to the substrate using diluted UV-curable glue. Consequently, three-dimensional nano-structures were formed by stacking the two-dimensional nano-patterned layers. RIL was applied to a light-emitting diode (LED) to evaluate the optical effects of a nano-patterned layer. As a result, the light extraction of the patterned LED was increased by about 12% compared to an unpatterned LED.

Synthesis of Co3O4 Cotton-Like Nanostructures for Cholesterol Biosensor

PubMed Central

Elhag, Sami; Ibupoto, Zafar Hussain; Nour, Omer; Willander, Magnus

2014-01-01

The use of templates to assist and possess a control over the synthesis of nanomaterials has been an attractive option to achieve this goal. Here we have used sodium dodecyl sulfate (SDS) to act as a template for the low temperature synthesis of cobalt oxide (Co3O4) nanostructures. The use of SDS has led to tune the morphology, and the product was in the form of “cotton-like” nanostructures instead of connected nanowires. Moreover, the variation of the amount of the SDS used was found to affect the charge transfer process in the Co3O4. Using Co3O4 synthesized using the SDS for sensing of cholesterol was investigated. The use of the Co3O4 synthesized using the SDS was found to yield an improved cholesterol biosensor compared to Co3O4 synthesized without the SDS. The improvement of the cholesterol sensing properties upon using the SDS as a template was manifested in increasing the sensitivity and the dynamic range of detection. The results achieved in this study indicate the potential of using template assisted synthesis of nanomaterials in improving some properties, e.g., cholesterol sensing. PMID:28787929

Synthesis of porous carbon/silica nanostructured microfiber with ultrahigh surface area

NASA Astrophysics Data System (ADS)

Zhou, Dan; Dong, Yan; Cui, Liru; Lin, Huiming; Qu, Fengyu

2014-12-01

Carbon/silica-nanostructured microfibers were synthesized via electrospinning method using phenol-formaldehyde resin and tetraethyl orthosilicate as carbon and silica precursor with triblock copolymer Pluronic P123 as soft template. The prepared samples show uniform microfiber structure with 1 μm in diameter and dozens of microns in length. Additionally, the mesopores in the material is about 2-6 nm. When the silica component was removed by HF, the porous carbon microfibers (PCMFs) were obtained. In addition, after the carbon/silica composites were calcined in air, the porous silica microfibers (PSiMFs) were obtained, revealing the converse porous nanostructure as PCMFs. It is a simple way to prepare PCMFs and PSiMFs with silica and carbon as the template to each other. Additionally, PCMFs possess an ultrahigh specific surface area (2,092 m2 g-1) and large pore volume. The electrochemical performance of the prepared PCMF material was investigated in 6.0 M KOH electrolyte. The PCMF electrode exhibits a high specific capacitance (252 F g-1 at 0.5 A g-1). Then, superior cycling stability (97 % retention after 4,000 cycles) mainly is due to its unique nanostructure.

Fabrication of Flower-like ZnO Micro/Nanostructures for Photodegradation of Pre-treated Palm Oil Mill Effluent

NASA Astrophysics Data System (ADS)

Lam, Sze-Mun; Wong, Kok-Ann; Sin, Jin-Chung

2018-01-01

Flower-like ZnO micro/nanostructures were fabricated by a simple and surfactant-free reflux method. X-ray diffraction findings showed that the prepared ZnO product was highly crystallite with hexagonal wurtzite structure. The band gap energy of ZnO sample was measured to be 3.18 eV via an optical reflectance spectrum. The flower-like morphological features of ZnO micro/nanostructures were witnessed through field-emission scanning electron microscopy. Such micro/nanoparticles could be used in the photodegradation of pre-treated palm oil mil effluent (POME) under UV irradiation.

Controlled growth of novel hyper-branched nanostructures in nanoporous alumina membrane.

PubMed

Zhang, Junping; Day, Cynthia S; Carroll, David L

2009-12-07

This paper proposes a novel approach to fabricate hyper-branched anodic aluminium oxide (AAO) nanostructures with different branches on the vertically-aligned trunk and at the trunk terminal. Silver nanowires with different dimensional and multifunctional complexity have been prepared from this hyper-branched AAO template by varying the electrodeposition time. These kinds of novel nanostructure may be used to build blocks for nanoelectronic and nanophotonic devices.

A Comprehensive Review of Glucose Biosensors Based on Nanostructured Metal-Oxides

PubMed Central

Rahman, Md. Mahbubur; Saleh Ahammad, A. J.; Jin, Joon-Hyung; Ahn, Sang Jung; Lee, Jae-Joon

2010-01-01

Nanotechnology has opened new and exhilarating opportunities for exploring glucose biosensing applications of the newly prepared nanostructured materials. Nanostructured metal-oxides have been extensively explored to develop biosensors with high sensitivity, fast response times, and stability for the determination of glucose by electrochemical oxidation. This article concentrates mainly on the development of different nanostructured metal-oxide [such as ZnO, Cu(I)/(II) oxides, MnO2, TiO2, CeO2, SiO2, ZrO2, and other metal-oxides] based glucose biosensors. Additionally, we devote our attention to the operating principles (i.e., potentiometric, amperometric, impedimetric and conductometric) of these nanostructured metal-oxide based glucose sensors. Finally, this review concludes with a personal prospective and some challenges of these nanoscaled sensors. PMID:22399911

Elastic anomalies and acoustic dissipation associated with spin state transitions in LnCoO3 (Ln=La, Nd, Gd) and Co3O4: analogue behaviour for spin state transitions in minerals

NASA Astrophysics Data System (ADS)

Zhang, Z.; Carpenter, M. A.; Koppensteiner, J.; Schranz, W.

2010-12-01

Iron ions in lower mantle minerals magnesiowüstitue (Mg,Fe)O, perovskite (Mg,Fe)(Si,Al)O3 and post-perovskite phases undergo electronic spin state transitions from high spin (HS) to low spin (LS) or intermediate spin (IS) at high pressures and high temperatures. These spin state transitions give rise to changes in bulk and shear moduli which have significant implications for the physical and chemical properties of the lower mantle. However, the possibility of increased attenuation does not appear to have been considered yet. Co3+ is isoelectronic with Fe2+ and shows analogous HS/LS behaviour at ambient pressure in a temperature range which is easily accessible for in-situ investigations. We have studied spin state transitions in cobalt perovskites LaCoO3, NdCoO3, GdCoO3 and in Co3O4 using resonant ultrasound spectroscopy (RUS) at high frequencies 0.1-1.5 MHz, and dynamic mechanical analysis (DMA) at low frequencies 0.1-50 Hz, in the temperature range 10-1200 K. The specific objectives were to characterize anomalies in the shear moduli and in acoustic attenuation accompanying changes in the spin state of Co3+. Anomalies in shear moduli have been observed at ~110 K and ~590 K for LaCoO3, ~325 K and ~695 K for NdCoO3, ~720 K for GdCoO3, and ~30 K for Co3O4. For LaCoO3, a spin order parameter qspin is expected to couple with volume strain ea as λeaqspin and with shear strain es as λes2qspin. As a consequence of linear/quadratic coupling with es, the shear modulus is expected to vary linearly with qspin. This appears to be approximately the case for LaCoO3. Changes in spin state do not appear to give rise to acoustic attenuation at either DMA frequencies (~1 Hz) or RUS frequencies (~1 MHz), consistent with the expectation that spin/lattice relaxation is rapid in comparison with the time scale of applied stress in each case. On the other hand, for LaCoO3 there is a peak in dissipation near 590 K at low frequencies, which is attributed to freezing of ferroelastic twin

Controlling of ZnO nanostructures by solute concentration and its effect on growth, structural and optical properties

NASA Astrophysics Data System (ADS)

Kumar, Yogendra; Rana, Amit Kumar; Bhojane, Prateek; Pusty, Manojit; Bagwe, Vivas; Sen, Somaditya; Shirage, Parasharam M.

2015-10-01

ZnO nanostructured films were prepared by a chemical bath deposition method on glass substrates without any assistance of either microwave or high pressure autoclaves. The effect of solute concentration on the pure wurtzite ZnO nanostructure morphologies is studied. The control of the solute concentration helps to control the nanostructure to form nano-needles, and -rods. X-ray diffraction (XRD) studies revealed highly c-axis oriented thin films. Scanning electron microscopy (SEM) confirms the modification of the nanostructure dependent on the concentration. Transmission electron microscopy (TEM) results show the single crystalline electron diffraction pattern, indicating high quality nano-material. UV-vis results show the variation in the band gap from 3.20 eV to 3.14 eV with increasing concentration as the nanostructures change from needle- to rod-like. Photoluminescence (PL) data indicate the existence of defects in the nanomaterials emitting light in the yellow-green region, with broad UV and visible spectra. A sharp and strong peak is observed at ˜438 cm-1 by Raman spectroscopy, assigned to the {{{{E}}}2}{{high}} optical mode of ZnO, the characteristic peak for the highly-crystalline wurtzite hexagonal phase. The solute concentration significantly affects the formation of defect states in the nanostructured films, and as a result, it alters the structural and optical properties. Current-voltage characteristics alter with the measurement environment, indicating potential sensor applications.

Aggregate nanostructures of organic molecular materials.

PubMed

Liu, Huibiao; Xu, Jialiang; Li, Yongjun; Li, Yuliang

2010-12-21

Conjugated organic molecules are interesting materials because of their structures and their electronic, electrical, magnetic, optical, biological, and chemical properties. However, researchers continue to face great challenges in the construction of well-defined organic compounds that aggregate into larger molecular materials such as nanowires, tubes, rods, particles, walls, films, and other structural arrays. Such nanoscale materials could serve as direct device components. In this Account, we describe our recent progress in the construction of nanostructures formed through the aggregation of organic conjugated molecules and in the investigation of the optical, electrical, and electronic properties that depend on the size or morphology of these nanostructures. We have designed and synthesized functional conjugated organic molecules with structural features that favor assembly into aggregate nanostructures via weak intermolecular interactions. These large-area ordered molecular aggregate nanostructures are based on a variety of simpler structures such as fullerenes, perylenes, anthracenes, porphyrins, polydiacetylenes, and their derivatives. We have developed new methods to construct these larger structures including organic vapor-solid phase reaction, natural growth, association via self-polymerization and self-organization, and a combination of self-assembly and electrochemical growth. These methods are both facile and reliable, allowing us to produce ordered and aligned aggregate nanostructures, such as large-area arrays of nanowires, nanorods, and nanotubes. In addition, we can synthesize nanoscale materials with controlled properties. Large-area ordered aggregate nanostructures exhibit interesting electrical, optical, and optoelectronic properties. We also describe the preparation of large-area aggregate nanostructures of charge transfer (CT) complexes using an organic solid-phase reaction technique. By this process, we can finely control the morphologies and

Electronic properties of one-dimensional nanostructures of the Bi2Se3 topological insulator

NASA Astrophysics Data System (ADS)

Virk, Naunidh; Autès, Gabriel; Yazyev, Oleg V.

2018-04-01

We theoretically study the electronic structure and spin properties of one-dimensional nanostructures of the prototypical bulk topological insulator Bi2Se3 . Realistic models of experimentally observed Bi2Se3 nanowires and nanoribbons are considered using the tight-binding method. At low energies, the band structures are composed of a series of evenly spaced degenerate subbands resulting from circumferential confinement of the topological surface states. The direct band gaps due to the nontrivial π Berry phase show a clear dependence on the circumference. The spin-momentum locking of the topological surface states results in a pronounced 2 π spin rotation around the circumference with the degree of spin polarization dependent on the momentum along the nanostructure. Overall, the band structures and spin textures are more complicated for nanoribbons, which expose two distinct facets. The effects of reduced dimensionality are rationalized with the help of a simple model that considers circumferential quantization of the topological surface states. Furthermore, the surface spin density induced by an electric current along the nanostructure shows a pronounced oscillatory dependence on the charge-carrier energy, which can be exploited in spintronics applications.

Synthesis and Plasmonic Understanding of Core/Satellite and Core Shell Nanostructures

NASA Astrophysics Data System (ADS)

Ruan, Qifeng

Localized surface plasmon resonance, which stems from the collective oscillations of conduction-band electrons, endows Au nanocrystals with unique optical properties. Au nanocrystals possess extremely large scattering/absorption cross-sections and enhanced local electromagnetic field, both of which are synthetically tunable. Moreover, when Au nanocrystals are closely placed or hybridized with semiconductors, the coupling and interaction between the individual components bring about more fascinating phenomena and promising applications, including plasmon-enhanced spectroscopies, solar energy harvesting, and cancer therapy. The continuous development in the field of plasmonics calls for further advancements in the preparation of high-quality plasmonic nanocrystals, the facile construction of hybrid plasmonic nanostructures with desired functionalities, as well as deeper understanding and efficient utilization of the interaction between plasmonic nanocrystals and semiconductor components. In this thesis, I developed a seed-mediated growth method for producing size-controlled Au nanospheres with high monodispersity and assembled Au nanospheres of different sizes into core/satellite nanostructures for enhancing Raman signals. For investigating the interactions between Au nanocrystals and semiconductors, I first prepared (Au core) (TiO2 shell) nanostructures, and then studied their synthetically controlled plasmonic properties and light-harvesting applications. Au nanocrystals with spherical shapes are desirable in plasmon-coupled systems owing to their high geometrical symmetry, which facilitates the analysis of electrodynamic responses in a classical electromagnetic framework and the investigation of quantum tunneling and nonlocal effects. I prepared remarkably uniform Au nanospheres with diameters ranging from 20 nm to 220 nm using a simple seed-mediated growth method associated with mild oxidation. Core/satellite nanostructures were assembled out of differently sized

Synthesis and photocatalytic properties of TiO{sub 2} nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xia, X.H.; Liang, Y.; Wang, Z.

2008-08-04

TiO{sub 2} particles, rods, flowers and sheets were prepared by hydrothermal method via adjusting the temperature, the pressure and the concentration of TiCl{sub 4}. The as-prepared TiO{sub 2} powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra and N{sub 2} adsorption-desorption measurements. It was found that pressure is the most important factor influencing the morphology of TiO{sub 2}. The photocatalytic activity of the products was evaluated by the photodegradation of aqueous brilliant red X-3B solution under UV light. Among the as-prepared nanostructures, the flower-like TiO{sub 2}more » exhibited the highest photocatalytic activity.« less

Hybrid nanostructures of metal/two-dimensional nanomaterials for plasmon-enhanced applications.

PubMed

Li, Xuanhua; Zhu, Jinmeng; Wei, Bingqing

2016-06-07

Hybrid nanostructures composed of graphene or other two-dimensional (2D) nanomaterials and plasmonic metal components have been extensively studied. The unusual properties of 2D materials are associated with their atomically thin thickness and 2D morphology, and many impressive structures enable the metal nanomaterials to establish various interesting hybrid nanostructures with outstanding plasmonic properties. In addition, the hybrid nanostructures display unique optical characteristics that are derived from the close conjunction of plasmonic optical effects and the unique physicochemical properties of 2D materials. More importantly, the hybrid nanostructures show several plasmonic electrical effects including an improved photogeneration rate, efficient carrier transfer, and a plasmon-induced "hot carrier", playing a significant role in enhancing device performance. They have been widely studied for plasmon-enhanced optical signals, photocatalysis, photodetectors (PDs), and solar cells. In this review, the developments in the field of metal/2D hybrid nanostructures are comprehensively described. Preparation of hybrid nanostructures is first presented according to the 2D material type, as well as the metal nanomaterial morphology. The plasmonic properties and the enabled applications of the hybrid nanostructures are then described. Lastly, possible future research in this promising field is discussed.

High Strength and Thermally Stable Nanostructured Magnesium Alloys and Nanocomposites

NASA Astrophysics Data System (ADS)

Chang, Yuan-Wei

Magnesium and its alloys are currently in the spotlight of global research because of the need to limit energy consumption and reduce the environmental impact. In particular, their low densities compared to other structural metals make them a very attractive alternative in the automobile and aerospace industries. However, their low strength compared to other structural materials (e.g. Al and steels) has limited their widespread application. This dissertation presents the results of developing and investigation of a high strength nanostructured magnesium-aluminum alloy and composite. The nanostructured magnesium alloy is prepared by cryomilling and consolidated by spark-plasma-sintering. Focused ion beam is used to prepare micropillars with different diameters ranging from 1.5 to 8 mum and micro-compression test is conducted by nanoindenter in order to evaluate the mechanical properties. The yield strength obtained in the present study is around three times higher than conventional magnesium alloys (120 MPa vs. 370 MPa). The yield strength of the nanostructured magnesium alloy is further improved through hot extrusion, resulting in a yield strength of 550 MPa and an ultimate strength of 580 MPa. The nanostructured magnesium alloy exhibits a strong size-dependence, and a significant improvement in strength is observed when the pillar diameter is reduced to below 3.5 mum. The deformation mechanisms of the compressed pillars were characterized using transmission electron microscopy. The size-induced strengthening is attributed to a less number of dislocation sources along with a higher activity of non-basal deformation mechanisms. We have also developed a high strength and thermally stable nanostructured magnesium composite by adding diamantane. A yield strength of 500 MPa is achieved, moreover, excellent thermal stability is demonstrated in the magnesium alloy containing diamantanes. The strength and grain size are thermally stable after annealing at 400°C for 100

New nanostructured ceramics from baddeleyite with improved mechanical properties for biomedical applications

NASA Astrophysics Data System (ADS)

Tyurin, Alexander I.; Zhigachev, Andrey O.; Umrikhin, Alexey V.; Rodaev, Vyacheslav V.; Korenkov, Viktor V.; Pirozhkova, Tatyana S.

2017-12-01

A method for the preparation of novel nanostructured zirconia ceramics from natural zirconia mineral—baddeleyite—using CaO as the stabilizer is described in the present work. Optimal synthesis conditions, including calcia content, planetary mill treatment regime, sintering time and temperature, corresponding to the highest values of hardness H, Young modulus E, and fracture toughness KC are found. The values of the mechanical properties H = 10.8 GPa, E = 200 GPa, and KC = 13.3 MPa m1/2 are comparable with or exceed the corresponding properties of commercial yttria-stabilized ceramics prepared from chemically precipitated zirconia.

Nanostructured Lipid Carriers Loaded with Baicalin: An Efficient Carrier for Enhanced Antidiabetic Effects

PubMed Central

Shi, Feng; Wei, Zheng; Zhao, Yingying; Xu, Ximing

2016-01-01

Context: Recent studies have demonstrated that baicalin has antihyperglycemic effects by inhibiting lipid peroxidation. Baicalin is low hydrophilic and poorly absorbed after oral administration. Thus, a suitable formulation is highly desired to overcome the disadvantages of baicalin. Objective: The objective of this work was to prepare baicalin-loaded nanostructured lipid carriers (B-NLCs) for enhanced antidiabetic effects. Materials and Methods: B-NLCs were prepared by high-pressure homogenization method using Precirol as the solid lipid and Miglyol as the liquid lipid. The properties of the NLCs, such as particle size, zeta potential (ZP), and drug encapsulation efficiency (EE), were investigated. The morphology of NLCs was observed by transmission electron microscopy. In addition, drug release and antidiabetic activity were also studied. Results: The results revealed that B-NLCs particles were uniformly in the nanosize range and of spherical morphology with a mean size of 92 ± 3.1 nm, a ZP of −31.35 ± 3.08 mV, and an EE of 85.29 ± 3.42%. Baicalin was released from NLCs in a sustained manner. In addition, B-NLCs showed a significantly higher antidiabetic efficacy compared with baicalin. Conclusion: B-NLCs described in this study are well-suited for the delivery of baicalin. SUMMARY Currently, herbal medicines have attracted increasing attention as a complementary approach for type 2 diabetesBaicalin has antihyperglycemic effects by inhibiting lipid peroxidationA suitable formulation is highly desired to overcome the disadvantages (poor solubility and low bioavailability) of baicalinNanostructured lipid carriers could enhance the antidiabetic effects of baicalin. Abbreviations used: B-NLCs: Baicalin-Loaded Nanostructured Lipid Carriers, B-SUS: Baicalin Water Suspension, EE: Encapsulation Efficiency, FBG: Fasting Blood Glucose, HbAlc: Glycosylated Hemoglobin, HPLC: High-performance Liquid Chromatography; NLCs: Nanostructured Lipid Carriers, PI: Polydispersity

Structural Engineering of Carbon and Metal Nanostructures for Antibacterial Applications

NASA Astrophysics Data System (ADS)

Rojas-Andrade, Mauricio D.

Cu alloy nanoparticles is presented. A comprehensive characterization of Ag, Cu, and AgCu alloy nanoparticle structures is first presented, followed by a thorough analysis of their antibacterial activities. AgCu alloy nanoparticles with an average size of 5 nm and an equal composition of Ag and Cu were found to be the most effective at inhibiting bacterial growth. The mechanisms of Ag, Cu, and AgCu alloy nanoparticles cytotoxicity is then further investigated using fluorescence microscopy and electron paramagnetic resonance (EPR) experiments. AgCu alloy nanoparticles are concluded to exhibit their marked activity due to enhanced reactive oxygen species (ROS) generation resulting from increased Fenton reactions catalyzed by copper species stabilized in the homogenous bimetallic alloy structure. Finally, in chapter 3, the antibacterial activity of graphene oxide quantum dots (GOQD) is reported. The as-prepared structures were synthesized through an established top-down approach, and a sodium borohydride-reduced derivative (rGOQD) was synthesized using these as the precursor. Using a variety of spectroscopic techniques, the structural properties are characterized and differences between as-prepared and reduced GOQD established. Their cytotoxicity toward bacterial cells with and without light irradiation is presented, with GOQDs demonstrating apparent activity under dark conditions, and rGOQD only under light irradiation. A mechanism of cytotoxicity and phototoxicty is proposed, which can be used to establish a foundation by which the cytotoxicity of all carbon nanostructures can be understood.

Nanostructured core-shell electrode materials for electrochemical capacitors

NASA Astrophysics Data System (ADS)

Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

2016-11-01

Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

Nanostructured Metal Oxides for Stoichiometric Degradation of Chemical Warfare Agents.

PubMed

Štengl, Václav; Henych, Jiří; Janoš, Pavel; Skoumal, Miroslav

2016-01-01

Metal oxides have very important applications in many areas of chemistry, physics and materials science; their properties are dependent on the method of preparation, the morphology and texture. Nanostructured metal oxides can exhibit unique characteristics unlike those of the bulk form depending on their morphology, with a high density of edges, corners and defect surfaces. In recent years, methods have been developed for the preparation of metal oxide powders with tunable control of the primary particle size as well as of a secondary particle size: the size of agglomerates of crystallites. One of the many ways to take advantage of unique properties of nanostructured oxide materials is stoichiometric degradation of chemical warfare agents (CWAs) and volatile organic compounds (VOC) pollutants on their surfaces.

Preparation of Deep Sea Fish Oil-Based Nanostructured Lipid Carriers with Enhanced Cellular Uptake.

PubMed

Zhu, Qiu-Yun; Guissi, Fida; Yang, Ru-Ya; Wang, Qian; Wang, Ke; Chen, Dan; Han, Zhi-Hao; Ma, Yi; Zhang, Min; Gu, Yue-Qing

2015-12-01

Nanostructured lipid carriers (NLC) are a promising pharmaceutical delivery system with mean diameter less than 200 nm which are dispersed in an aqueous phase containing emulsifier(s), to increase the water solubility, stability and bioavailability of oil compounds. Herein we prepared a promising NLC with glyceryl monostearate (GMS) as the solid lipid template and deep sea fish oil as the liquid lipid template using melted-ultrasonic method. Fish oil-NLC had a mean size of 84.7 ± 2.6 nm and a zeta potential that ranged from -17.87 mV to -32.91 mV. The nanoparticles exhibited good stability for four weeks with a high encapsulation efficiency of 87.5 ± 5.2%. Afterwards, confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) were used to investigate the contribution of Fish oil-NLC in enhancing fluorescein isothiocyanate (FITC) cellular uptake in comparison with free FITC. The results of this study indicated the possibility of this carrier to overcome the shortcomings of deep sea fish oil and to provide a novel bifunctional carrier with nutritional potential and drug delivery ability.

Interface-mediated ferroelectric patterning and Mn valency in nano-structured PbTiO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krug, Ingo P.; Institut für Optik and Atomare Physik; Helmholtzzentrum für Materialien und Energie

2016-09-07

We employed a multitechnique approach using piezo-force response microscopy and photoemission microscopy to investigate a self-organizing polarization domain pattern in PbTiO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (PTO/LSMO) nanostructures. The polarization is correlated with the nanostructure morphology as well as with the thickness and Mn valence of the LSMO template layer. On the LSMO dots, the PTO is upwards polarized, whereas outside the nanodots, the polarization appears both strain and interface roughness dependent. The results suggest that the electronic structure and strain of the PTO/LSMO interface contribute to determining the internal bias of the ferroelectric layer.

Hydrogen peroxide-assisted synthesis of novel three-dimensional octagonal-like CuO nanostructures with enhanced visible-light-driven photocatalytic activity

NASA Astrophysics Data System (ADS)

Chen, Xiangyu; Chu, Deqing; Wang, Limin; Hu, Wenhui; Yang, Huifang; Sun, Jingjing; Zhu, Shaopeng; Wang, Guowei; Tao, Jian; Zhang, Songsong

2018-04-01

Novel three-dimensional octagonal-like CuO micro-/nanostructures with diameters ranging from 10 to 15 μm have been successfully prepared by hydrogen peroxide-assisted hydrothermal method and subsequent calcination. The product morphology can be changed by simply ordering the amount of hydrogen peroxide (H2O2). When the amounts of H2O2 is increased, the length of the corner portion is increased and the width is narrower. The obtained octagonal CuO nanostructures were evaluated for their ability for the degradation of hazardous organic contaminants in water under visible-light irradiation. Comparing with commercial CuO and other CuO products, the CuO octagonal nanostructures exhibit excellent performance for photocatalytic decomposition of RhB (Rhodamine B). It is well established that effective photocatalytic performance results from its unique 3D octagonal nanostructures. We believe that the present work will provide some ideas for further fabrication of other novel nanostructures and exploration of their applications.

Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

PubMed Central

Yuan, Liang (Leon); Herman, Peter R.

2016-01-01

Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

Composite materials formed with anchored nanostructures

DOEpatents

Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

2015-03-10

A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

Thymoquinone-loaded nanostructured lipid carriers: preparation, gastroprotection, in vitro toxicity, and pharmacokinetic properties after extravascular administration

PubMed Central

Abdelwahab, Siddig Ibrahim; Sheikh, Bassem Yousef; Taha, Manal Mohamed Elhassan; How, Chee Wun; Abdullah, Rasedee; Yagoub, Umar; El-Sunousi, Rashad; Eid, Eltayeb EM

2013-01-01

Background Nanostructured lipid carriers (NLCs), composed of solid and liquid lipids, and surfactants are potentially good colloidal drug carriers. Thymoquinone is the main bioactive compound of Nigella sativa. In this study, the preparation, gastroprotective effects, and pharmacokinetic (PK) properties of thymoquinone (TQ)-loaded NLCs (TQNLCs) were evaluated. Method TQNLCs were prepared using hydrogenated palm oil (Softisan® 154), olive oil, and phosphatidylcholine for the lipid phase and sorbitol, polysorbate 80, thimerosal, and double distilled water for the liquid lipid material. A morphological assessment of TQNLCs was performed using various methods. Analysis of the ulcer index, hydrogen concentration, mucus content, and biochemical and histochemical studies confirmed that the loading of TQ into the NLCs significantly improved the gastroprotective activity of this natural compound against the formation of ethanol-induced ulcers. The safety of TQNLC was tested on WRL68 liver normal cells with cisplatin as a positive control. Results The average diameter of the TQNLCs was 75 ± 2.4 nm. The particles had negative zeta potential values of −31 ± 0.1 mV and a single melting peak of 55.85°C. Immunohistochemical methods revealed that TQNLCs inhibited the formation of ethanol-induced ulcers through the modulation of heat shock protein-70 (Hsp70). Acute hepatotoxic effects of the TQNLCs were not observed in rats or normal human liver cells (WRL-68). After validation, PK studies in rabbits showed that the PK properties of TQ were improved and indicated that the drug behaves linearly. The Tmax, Cmax, and elimination half-life of TQ were found to be 3.96 ± 0.19 hours, 4811.33 ± 55.52 ng/mL, and 4.4933 ± 0.015 hours, respectively, indicating that TQ is suitable for extravascular administration. Conclusion NLCs could be a promising vehicle for the oral delivery of TQ and improve its gastroprotective properties. PMID:23818776

Rapid growth and photoluminescence properties of doped ZnS one-dimensional nanostructures

NASA Astrophysics Data System (ADS)

Zhuo, R. F.; Feng, H. T.; Yan, D.; Chen, J. T.; Feng, J. J.; Liu, J. Z.; Yan, P. X.

2008-06-01

In this paper we report the synthesis of doped ZnS one-dimensional (1D) nanostructures by well-established technique of chemical vapor deposition using Zn and S powder as precursors. The ZnS 1D nanostructures were grown on the surface of Au particle-filled anodic aluminum oxide templates, catalyst-free graphite sheets and silicon substrates. ZnS 1D nanostructures with Mn, Cu and Fe as dopants were prepared via a rapid process of 15-20 min. The morphologies of ZnS nanostructures synthesized on different substrates and at different growth temperatures have distinct dissimilarities. The size of ZnS nanowires originated from the Au catalysts could be varied by altering the size of membrane nanopores as well as the embedded Au particles. Room-temperature photoluminescence measurements reveal strong blue, green and yellow-orange light emissions from the doped ZnS 1D nanostructures.

A Strategy for Fabricating Porous PdNi@Pt Core-shell Nanostructures and Their Enhanced Activity and Durability for the Methanol Electrooxidation

PubMed Central

Liu, Xinyu; Xu, Guangrui; Chen, Yu; Lu, Tianhong; Tang, Yawen; Xing, Wei

2015-01-01

Three-dimensionally (3D) porous morphology of nanostructures can effectively improve their electrocatalytic activity and durability for various electrochemical reactions owing to big surface area and interconnected structure. Cyanogel, a jelly-like inorganic polymer, can be used to synthesize various three-dimensionally (3D) porous alloy nanomaterials owing to its double-metal property and particular 3D backbone. Here, 3D porous PdNi@Pt core-shell nanostructures (CSNSs) are facilely synthesized by first preparing the Pd-Ni alloy networks (Pd-Ni ANWs) core via cyanogel-reduction method followed by a galvanic displacement reaction to generate the Pt-rich shell. The as-synthesized PdNi@Pt CSNSs exhibit a much improved catalytic activity and durability for the methanol oxidation reaction (MOR) in the acidic media compared to the commercial used Pt black because of their specific structural characteristics. The facile and mild method described herein is highly attractive for the synthisis of 3D porous core-shell nanostructures. PMID:25557190

Preparation and characterization of dutasteride-loaded nanostructured lipid carriers coated with stearic acid-chitosan oligomer for topical delivery.

PubMed

Noor, Norhayati Mohamed; Sheikh, Khalid; Somavarapu, Satyanarayana; Taylor, Kevin M G

2017-08-01

Dutasteride, used for treating benign prostate hyperplasia (BPH), promotes hair growth. To enhance delivery to the hair follicles and reduce systemic effects, in this study dutasteride has been formulated for topical application, in a nanostructured lipid carrier (NLC) coated with chitosan oligomer-stearic acid (CSO-SA). CSO-SA has been successfully synthesized, as confirmed using 1 H NMR and FTIR. Formulation of dutasteride-loaded nanostructured lipid carriers (DST-NLCs) was optimized using a 2 3 full factorial design. This formulation was coated with different concentrations of stearic acid-chitosan solution. Coating DST-NLCs with 5% SA-CSO increased mean size from 187.6±7.0nm to 220.1±11.9nm, and modified surface charge, with zeta potentials being -18.3±0.9mV and +25.8±1.1mV for uncoated and coated DST-NLCs respectively. Transmission electron microscopy showed all formulations comprised approximately spherical particles. DST-NLCs, coated and uncoated with CSO-SA, exhibited particle size stability over 60days, when stored at 4-8°C. However, NLCs coated with CSO (without conjugation) showed aggregation when stored at 4-8°C after 30days. The measured particle size for all formulations stored at 25°C suggested aggregation, which was greatest for DST-NLCs coated with 10% CSO-SA and 5% CSO. All nanoparticle formulations exhibited rapid release in an in vitro release study, with uncoated NLCs exhibiting the fastest release rate. Using a Franz diffusion cell, no dutasteride permeated through pig ear skin after 48h, such that it was not detected in the receptor chamber for all samples. The amount of dutasteride in the skin was significantly different (p<0.05) for DST-NLCs (6.09±1.09μg/cm 2 ) without coating and those coated with 5% CSO-SA (2.82±0.40μg/cm 2 ), 10% CSO-SA (2.70±0.35μg/cm 2 ) and CSO (2.11±0.64μg/cm 2) . There was a significant difference (p<0.05) in the cytotoxicity (IC 50 ) between dutasteride alone and in the nanoparticles. DST-NLCs coated

Rambutan-like FeCO3 hollow microspheres: facile preparation and superior lithium storage performances.

PubMed

Zhong, Yiren; Su, Liwei; Yang, Mei; Wei, Jinping; Zhou, Zhen

2013-11-13

Rambutan-like FeCO3 hollow microspheres were prepared via a facile and economic one-step hydrothermal method. The structure and morphology evolution mechanism was disclosed through time-dependent experiments. After undergoing the symmetric inside-out Ostwald ripening, the resultants formed microporous/nanoporous constructions composed of numerous one-dimensional (1D) nanofiber building blocks. Tested as anode materials of Li-ion batteries, FeCO3 hollow microspheres presented attractive electrochemical performances. The capacities were over 1000 mAh g(-1) for initial charge, ~880 mAh g(-1) after 100 cycles at 50 mA g(-1), and ~710 mAh g(-1) after 200 cycles at 200 mA g(-1). The 1D nanofiber assembly and hollow interior endow this material efficient contact with electrolyte, short Li(+) diffusion paths, and sufficient void spaces to accommodate large volume variation. The cost-efficient FeCO3 with rationally designed nanostructures is a promising anode candidate for Li-ion batteries.

Facile fabrication of homogeneous 3D silver nanostructures on gold-supported polyaniline membranes as promising SERS substrates.

PubMed

Xu, Ping; Mack, Nathan H; Jeon, Sea-Ho; Doorn, Stephen K; Han, Xijiang; Wang, Hsing-Lin

2010-06-01

We report a facile synthesis of large-area homogeneous three-dimensional (3D) Ag nanostructures on Au-supported polyaniline (PANI) membranes through a direct chemical reduction of metal ions by PANI. The citric acid absorbed on the Au nuclei that are prefabricated on PANI membranes directs Ag nanoaprticles (AgNPs) to self-assemble into 3D Ag nanosheet structures. The fabricated hybrid metal nanostructures display uniform surface-enhanced Raman scattering (SERS) responses throughout the whole surface area, with an average enhancement factor of 10(6)-10(7). The nanocavities formed by the stereotypical stacking of these Ag nanosheets and the junctions and gaps between two neighboring AgNPs are believed to be responsible for the strong SERS response upon plasmon absorption. These homogeneous metal nanostructure decorated PANI membranes can be used as highly efficient SERS substrates for sensitive detection of chemical and biological analytes.

A general and high-yield galvanic displacement approach to Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells and enhanced electrocatalytic performances.

PubMed

Kuai, Long; Geng, Baoyou; Wang, Shaozhen; Sang, Yan

2012-07-23

In this work, we utilize the galvanic displacement synthesis and make it a general and efficient method for the preparation of Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells, which consist of multilayer nanoparticles. The method is generally applicable to the preparation of Au-Au, Au-Pd, and Au-Pt core-shell nanostructures with typical porous shells. Moreover, the Au-Au isomeric core-shell nanostructure is reported for the first time. The lower oxidation states of Au(I), Pd(II), and Pt(II) are supposed to contribute to the formation of porous core-shell nanostructures instead of yolk-shell nanostructures. The electrocatalytic ethanol oxidation and oxygen reduction reaction (ORR) performance of porous Au-Pd core-shell nanostructures are assessed as a typical example for the investigation of the advantages of the obtained core-shell nanostructures. As expected, the Au-Pd core-shell nanostructure indeed exhibits a significantly reduced overpotential (the peak potential is shifted in the positive direction by 44 mV and 32 mV), a much improved CO tolerance (I(f)/I(b) is 3.6 and 1.63 times higher), and an enhanced catalytic stability in comparison with Pd nanoparticles and Pt/C catalysts. Thus, porous Au-M (M = Au, Pd, and Pt) core-shell nanostructures may provide many opportunities in the fields of organic catalysis, direct alcohol fuel cells, surface-enhanced Raman scattering, and so forth. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding the effect models of ionic liquids in the synthesis of NH4-Dw and γ-AlOOH nanostructures and their conversion into porous γ-Al2O3.

PubMed

Duan, Xiaochuan; Kim, Tongil; Li, Di; Ma, Jianmin; Zheng, Wenjun

2013-05-03

Well-dispersed ammonium aluminum carbonate hydroxide (NH4-Dw) and γ-AlOOH nanostructures with controlled morphologies have been synthesized by employing an ionic-liquid-assisted hydrothermal process. The basic strategies that were used in this work were: 1) A controllable phase transition from NH4-Dw to γ-AlOOH could be realized by increasing the reaction temperature and 2) the morphological evolution of NH4-Dw and γ-AlOOH nanostructures could be influenced by the concentration of the ionic liquid. Based on these experimental results, the main objective of this work was to clarify the effect models of the ionic liquids on the synthesis of NH4-Dw and γ-AlOOH nanostructures, which could be divided into cationic- or anionic-dominant effect models, as determined by the different surface structures of the targets. Specifically, under the cationic-dominant regime, the ionic liquids mainly showed dispersion effects for the NH4-Dw nanostructures, whereas the anionic-dominant model could induce the self-assembly of the γ-AlOOH particles to form hierarchical structures. Under the guidance of the proposed models, the effect of the ionic liquids would be optimized by an appropriate choice of cations or anions, as well as by considering the different effect models with the substrate surface. We expect that such effect models between ionic liquids and the target products will be helpful for understanding and designing rational ionic liquids that contain specific functional groups, thus open up new opportunities for the synthesis of inorganic nanomaterials with new morphologies and improved properties. In addition, these as-prepared NH4-Dw and γ-AlOOH nanostructures were converted into porous γ-Al2O3 nanostructures by thermal decomposition, whilst preserving the same morphology. By using HRTEM and nitrogen-adsorption analysis, the obtained γ-Al2O3 samples were found to have excellent porous properties and, hence, may have applications in catalysis and adsorption

Synthesis and characterization of nanostructured bismuth selenide thin films.

PubMed

Sun, Zhengliang; Liufu, Shengcong; Chen, Lidong

2010-12-07

Nanostructured bismuth selenide thin films have been successfully fabricated on a silicon substrate at low temperature by rational design of the precursor solution. Bi(2)Se(3) thin films were constructed of coalesced lamella in the thickness of 50-80 nm. The nucleation and growth process of Bi(2)Se(3) thin films, as well as the influence of solution chemistry on the film structure were investigated in detail. As one of the most promising thermoelectric materials, the thermoelectric properties of the prepared Bi(2)Se(3) thin films were also investigated. The power factor increased with increasing carrier mobility, coming from the enlarged crystallites and enhanced coalesced structure, and reached 1 μW cm(-1) K(-1).

One-pot ultrasonic-assisted method for preparation of Ag/AgCl sensitized ZnO nanostructures as visible-light-driven photocatalysts

NASA Astrophysics Data System (ADS)

Naghizadeh-Alamdari, Sara; Habibi-Yangjeh, Aziz; Pirhashemi, Mahsa

2015-02-01

Ultrasonic-assisted method was applied for preparation of Ag/AgCl sensitized ZnO nanostructures by one-pot procedure in water without using any post preparation treatments. The resultant nanocomposites were characterized by XRD, EDX, SEM, DRS, XPS, BET, and PL techniques. In the nanocomposites, ZnO and AgCl have wurtzite hexagonal and cubic crystalline phases, respectively and their surface morphologies remarkably change with increasing mole fraction of silver chloride. The EDX and XPS techniques show that the prepared samples are extremely pure. Ability of the nanocomposites for absorption of visible-light irradiation enhanced with increasing AgCl content. Photocatalytic examination of the nanocomposites was carried out using aqueous solution of methylene blue under visible-light irradiation. The degradation rate constant on the nancomposite rapidly increases with mole fraction of silver chloride up to 0.237. Enhancing activity of the nanocomposite was attributed to its ability for absorbing visible light and separation of electron-hole pairs. Furthermore, influence of ultrasonic irradiation time, calcination temperature, catalyst weight, pH of solution, and scavengers of reactive species on the degradation activity was investigated and the results were discussed. Finally, the photocatalyst has good activity after five successive cycles.

Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles.

PubMed

Villani, M; Rimoldi, T; Calestani, D; Lazzarini, L; Chiesi, V; Casoli, F; Albertini, F; Zappettini, A

2013-04-05

A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis.

Mechanical design of DNA nanostructures

NASA Astrophysics Data System (ADS)

Castro, Carlos E.; Su, Hai-Jun; Marras, Alexander E.; Zhou, Lifeng; Johnson, Joshua

2015-03-01

Structural DNA nanotechnology is a rapidly emerging field that has demonstrated great potential for applications such as single molecule sensing, drug delivery, and templating molecular components. As the applications of DNA nanotechnology expand, a consideration of their mechanical behavior is becoming essential to understand how these structures will respond to physical interactions. This review considers three major avenues of recent progress in this area: (1) measuring and designing mechanical properties of DNA nanostructures, (2) designing complex nanostructures based on imposed mechanical stresses, and (3) designing and controlling structurally dynamic nanostructures. This work has laid the foundation for mechanically active nanomachines that can generate, transmit, and respond to physical cues in molecular systems.Structural DNA nanotechnology is a rapidly emerging field that has demonstrated great potential for applications such as single molecule sensing, drug delivery, and templating molecular components. As the applications of DNA nanotechnology expand, a consideration of their mechanical behavior is becoming essential to understand how these structures will respond to physical interactions. This review considers three major avenues of recent progress in this area: (1) measuring and designing mechanical properties of DNA nanostructures, (2) designing complex nanostructures based on imposed mechanical stresses, and (3) designing and controlling structurally dynamic nanostructures. This work has laid the foundation for mechanically active nanomachines that can generate, transmit, and respond to physical cues in molecular systems. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07153k

In situ deformation and mechanical properties of bismuth telluride prepared via zone melting

NASA Astrophysics Data System (ADS)

Lai, Tang-Yu; Hsiao, Yu-Jen; Fang, Te-Hua

2018-03-01

In this study, we prepared Bi2Te3 nanostructures via zone melting and characterized their mechanical properties by nanoindentation and in situ transmission electron microscopy (TEM). The nanoindentation results revealed that a significant ‘pop-in’ phenomenon occurs under high-loading conditions with multiple dislocations and phase transitions in the material structure. Young’s modulus of the nanostructures was found to be 42.7 ± 2.56 GPa from nanoindentation measurements and 12.3 ± 0.1 GPa from in situ TEM measurements. The results of this study may be useful for the future development of Bi2Te3 thermoelectric devices via printing processes.

Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

PubMed

Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

2016-09-10

In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of nanostructured electrodes and interfaces using combustion CVD

NASA Astrophysics Data System (ADS)

Liu, Ying

Reducing fabrication and operation costs while maintaining high performance is a major consideration for the design of a new generation of solid-state ionic devices such as fuel cells, batteries, and sensors. The objective of this research is to fabricate nanostructured materials for energy storage and conversion, particularly porous electrodes with nanostructured features for solid oxide fuel cells (SOFCs) and high surface area films for gas sensing using a combustion CVD process. This research started with the evaluation of the most important deposition parameters: deposition temperature, deposition time, precursor concentration, and substrate. With the optimum deposition parameters, highly porous and nanostructured electrodes for low-temperature SOFCs have been then fabricated. Further, nanostructured and functionally graded La0.8Sr0.2MnO2-La 0.8SrCoO3-Gd0.1Ce0.9O2 composite cathodes were fabricated on YSZ electrolyte supports. Extremely low interfacial polarization resistances (i.e. 0.43 Ocm2 at 700°C) and high power densities (i.e. 481 mW/cm2 at 800°C) were generated at operating temperature range of 600°C--850°C. The original combustion CVD process is modified to directly employ solid ceramic powder instead of clear solution for fabrication of porous electrodes for solid oxide fuel cells. Solid particles of SOFC electrode materials suspended in an organic solvent were burned in a combustion flame, depositing a porous cathode on an anode supported electrolyte. Combustion CVD was also employed to fabricate highly porous and nanostructured SnO2 thin film gas sensors with Pt interdigitated electrodes. The as-prepared SnO2 gas sensors were tested for ethanol vapor sensing behavior in the temperature range of 200--500°C and showed excellent sensitivity, selectivity, and speed of response. Moreover, several novel nanostructures were synthesized using a combustion CVD process, including SnO2 nanotubes with square-shaped or rectangular cross sections, well

High-Yield Synthesis of Stoichiometric Boron Nitride Nanostructures

DOE PAGES

Nocua, José E.; Piazza, Fabrice; Weiner, Brad R.; ...

2009-01-01

Boron nimore » tride (BN) nanostructures are structural analogues of carbon nanostructures but have completely different bonding character and structural defects. They are chemically inert, electrically insulating, and potentially important in mechanical applications that include the strengthening of light structural materials. These applications require the reliable production of bulk amounts of pure BN nanostructures in order to be able to reinforce large quantities of structural materials, hence the need for the development of high-yield synthesis methods of pure BN nanostructures. Using borazine ( B 3 N 3 H 6 ) as chemical precursor and the hot-filament chemical vapor deposition (HFCVD) technique, pure BN nanostructures with cross-sectional sizes ranging between 20 and 50 nm were obtained, including nanoparticles and nanofibers. Their crystalline structure was characterized by (XRD), their morphology and nanostructure was examined by (SEM) and (TEM), while their chemical composition was studied by (EDS), (FTIR), (EELS), and (XPS). Taken altogether, the results indicate that all the material obtained is stoichiometric nanostructured BN with hexagonal and rhombohedral crystalline structure.« less

One-step direct-laser metal writing of sub-100 nm 3D silver nanostructures in a gelatin matrix

NASA Astrophysics Data System (ADS)

Kang, SeungYeon; Vora, Kevin; Mazur, Eric

2015-03-01

Developing an ability to fabricate high-resolution, 3D metal nanostructures in a stretchable 3D matrix is a critical step to realizing novel optoelectronic devices such as tunable bulk metal-dielectric optical devices and THz metamaterial devices that are not feasible with alternative techniques. We report a new chemistry method to fabricate high-resolution, 3D silver nanostructures using a femtosecond-laser direct metal writing technique. Previously, only fabrication of 3D polymeric structures or single-/few-layer metal structures was possible. Our method takes advantage of unique gelatin properties to overcome such previous limitations as limited freedom in 3D material design and short sample lifetime. We fabricate more than 15 layers of 3D silver nanostructures with a resolution of less than 100 nm in a stable dielectric matrix that is flexible and has high large transparency that is well-matched for potential applications in the optical and THz metamaterial regimes. This is a single-step process that does not require any further processing. This work will be of interest to those interested in fabrication methods that utilize nonlinear light-matter interactions and the realization of future metamaterials.

A Resumable Fluorescent Probe BHN-Fe3O4@SiO2 Hybrid Nanostructure for Fe3+ and its Application in Bioimaging

NASA Astrophysics Data System (ADS)

Zhou, Xi; Wang, Yujiao; Peng, Qi; Liu, Weisheng

2017-12-01

A multifunctional fluorescent probe BHN-Fe3O4@SiO2 nanostructure for Fe3+ was designed and developed. It has a good selective response to Fe3+ with fluorescence quenching and can be recycled using an external magnetic field. With adding EDTA (2.5 × 10-5 M) to the consequent product Fe3+-BHN-Fe3O4@SiO2, Fe3+ can be removed from the complex, and its fluorescence probing ability recovers, which means that this constituted on-off type fluorescence probe could be reversed and reused. At the same time, the probe has been successfully applied for quantitatively detecting Fe3+ in a linear mode with a low limit of detection 1.25 × 10-8 M. Furthermore, the BHN-Fe3O4@SiO2 nanostructure probe is successfully used to detect Fe3+ in living HeLa cells, which shows its great potential in bioimaging detection.

Facile hydrothermal synthesis and characterization of cesium-doped PbI2 nanostructures for optoelectronic, radiation detection and photocatalytic applications

NASA Astrophysics Data System (ADS)

Shkir, Mohd; AlFaify, S.; Yahia, I. S.; Hamdy, Mohamed S.; Ganesh, V.; Algarni, H.

2017-10-01

Low-temperature hydrothermal-assisted synthesis of pure and cesium (Cs) (1, 3, 5, 7 and 10 wt%) doped lead iodide (PbI2) nanorods and nanosheets have been achieved successfully for the first time. The structural and vibrational studies confirm the formation of a 2H-polytypic PbI2 predominantly. Scanning electron microscope analysis confirms the formation of well-aligned nanorods of average size 100 nm at low concentration and nanosheets of average thicknesses in the range of 20-40 nm at higher concentrations of Cs doping. The presence of Cs doping was confirmed by energy dispersive X-ray study. Ultra-violet-visible absorbance spectra were recorded, and energy gap was calculated in the range of 3.33 to 3.45 eV for pure and Cs-doped PbI2 nanostructures which is higher than the bulk value (i.e., 2.27 eV) due to quantum confinement effect. Dielectric constant, loss, and AC conductivity studies have been done. Enhancement in Gamma linear absorption coefficient due to Cs doping confirms the suitability of prepared nanostructures for radiation detection applications. Furthermore, the photocatalytic performance of the synthesized nanostructures was evaluated in the decolorization of methyl green (MG) and methyl orange (MO) under the illumination of visible light (λ > 420 nm). The observed photocatalytic activity for 5 and 7 wt% Cs-doped PbI2 was observed to be more than pure PbI2 and also > 10 times higher than the commercially available photocatalysts. The results suggest that the prepared nanostructures are highly applicable in optoelectronic, radiation detection and many other applications. [Figure not available: see fulltext.

A promising tritium breeding material: Nanostructured 2Li2TiO3-Li4SiO4 biphasic ceramic pebbles

NASA Astrophysics Data System (ADS)

Dang, Chen; Yang, Mao; Gong, Yichao; Feng, Lan; Wang, Hailiang; Shi, Yanli; Shi, Qiwu; Qi, Jianqi; Lu, Tiecheng

2018-03-01

As an advanced tritium breeder material for the fusion reactor blanket of the International Thermonuclear Experimental Reactor (ITER), Li2TiO3-Li4SiO4 biphasic ceramic has attracted widely attention due to its merits. In this paper, the uniform precursor powders were prepared by hydrothermal method, and nanostructured 2Li2TiO3-Li4SiO4 biphasic ceramic pebbles were fabricated by an indirect wet method at the first time. In addition, the composition dependence (x/y) of their microstructure characteristics and mechanical properties were investigated. The results indicated that the crush load of biphasic ceramic pebbles was better than that of single phase ceramic pebbles under identical conditions. The 2Li2TiO3-Li4SiO4 ceramic pebbles have good morphology, small grain size (90 nm), satisfactory crush load (37.8 N) and relative density (81.8 %T.D.), which could be a promising breeding material in the future fusion reactor.

Growth process and magnetic properties of α-FeSe nanostructures

NASA Astrophysics Data System (ADS)

Li, S. J.; Li, D.; Jiang, J. J.; Liu, G. B.; Ma, S.; Liu, W.; Zhang, Z. D.

2014-05-01

Growth process and magnetic properties of PbO-type α-FexSe nanostructures with shape changing from nanocacti to nanopetals and then to nanosheets are investigated. With iron acetylacetonate [Fe(acac)3] and Se powder as raw materials, the diffusion process of Fe atoms dominates the synthesis of α-FexSe nanocacti following phase transitions from FeSe2 to Fe3Se4 and finally to α-FexSe. When a mixed solution containing Se precursor and Fe(acac)3 was used as the raw material, the formation of FeSe2 and Fe3Se4 can be avoided and, bended α-FexSe nanopetals can be prepared at 345 °C, which became flat nanosheets with a [001] preferred orientation as extending the reaction time from 1 to 4 h. No superconducting transition occurs in the α-FexSe (0.84 ≤ x ≤ 1.05) nanostructures due to composition heterogeneity or size effect. Magnetic measurements indicate that an antiferromagnetic component with a Néel point at about 45 K dominates the magnetic properties of the α-Fe0.87Se nanosheets.

Supramolecular Differentiation for Construction of Anisotropic Fullerene Nanostructures by Time-Programmed Control of Interfacial Growth.

PubMed

Bairi, Partha; Minami, Kosuke; Hill, Jonathan P; Nakanishi, Waka; Shrestha, Lok Kumar; Liu, Chao; Harano, Koji; Nakamura, Eiichi; Ariga, Katsuhiko

2016-09-27

Supramolecular assembly can be used to construct a wide variety of ordered structures by exploiting the cumulative effects of multiple noncovalent interactions. However, the construction of anisotropic nanostructures remains subject to some limitations. Here, we demonstrate the preparation of anisotropic fullerene-based nanostructures by supramolecular differentiation, which is the programmed control of multiple assembly strategies. We have carefully combined interfacial assembly and local phase separation phenomena. Two fullerene derivatives, PhH and C12H, were together formed into self-assembled anisotropic nanostructures by using this approach. This technique is applicable for the construction of anisotropic nanostructures without requiring complex molecular design or complicated methodology.

Microwave-assisted green synthesis of silver nanostructures.

PubMed

Nadagouda, Mallikarjuna N; Speth, Thomas F; Varma, Rajender S

2011-07-19

Over the past 25 years, microwave (MW) chemistry has moved from a laboratory curiosity to a well-established synthetic technique used in many academic and industrial laboratories around the world. Although the overwhelming number of MW-assisted applications today are still performed on a laboratory (mL) scale, we expect that this enabling technology may be used on a larger, perhaps even production, scale in conjunction with radio frequency or conventional heating. Microwave chemistry is based on two main principles, the dipolar mechanism and the electrical conductor mechanism. The dipolar mechanism occurs when, under a very high frequency electric field, a polar molecule attempts to follow the field in the same alignment. When this happens, the molecules release enough heat to drive the reaction forward. In the second mechanism, the irradiated sample is an electrical conductor and the charge carriers, ions and electrons, move through the material under the influence of the electric field and lead to polarization within the sample. These induced currents and any electrical resistance will heat the sample. This Account summarizes a microwave (MW)-assisted synthetic approach for producing silver nanostructures. MW heating has received considerable attention as a promising new method for the one-pot synthesis of metallic nanostructures in solutions. Researchers have successfully demonstrated the application of this method in the preparation of silver (Ag), gold (Au), platinum (Pt), and gold-palladium (Au-Pd) nanostructures. MW heating conditions allow not only for the preparation of spherical nanoparticles within a few minutes but also for the formation of single crystalline polygonal plates, sheets, rods, wires, tubes, and dendrites. The morphologies and sizes of the nanostructures can be controlled by changing various experimental parameters, such as the concentration of metallic salt precursors, the surfactant polymers, the chain length of the surfactant polymers

Hydrothermal preparation of hierarchical ZIF-L nanostructures for enhanced CO2 capture.

PubMed

Ding, Bing; Wang, Xianbiao; Xu, Yongfei; Feng, Shaojie; Ding, Yi; Pan, Yang; Xu, Weifan; Wang, Huanting

2018-06-01

A zeolitic imidazolate framework (ZIF-L) with hierarchical morphology was synthesized through hydrothermal method. The hierarchical product consists of ZIF-L leaves with length of several micrometers, width of 1 ∼ 2 μm and thickness of ∼300 nm cross connected symmetrically. It was found that the hydrothermal temperature is crucial for the formation of such hierarchical nanostructure. The formation mechanism was investigated to be a secondary crystal growth process. The hierarchical ZIF-L has larger surface area compared with the two-dimensional (2D) ZIF-L leaves. Subsequently, the hierarchical ZIF-L exhibited enhanced CO 2 adsorption capacity (1.56 mmol·g -1 ) as compared with that of the reported two-dimensional ZIF-L leaves (0.94 mmol·g -1 ). This work not only reveals a new strategy for the formation of hierarchical ZIF-L nanostructures, but also supplies a potential material for CO 2 capture. Copyright © 2018 Elsevier Inc. All rights reserved.

Engineering of high performance supercapacitor electrode based on Fe-Ni/Fe{sub 2}O{sub 3}-NiO core/shell hybrid nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Ashutosh K., E-mail: ashuvishen@gmail.com, E-mail: aksingh@bose.res.in; Mandal, Kalyan

The present work reports on fabrication and supercapacitor applications of a core/shell Fe-Ni/Fe{sub 2}O{sub 3}-NiO hybrid nanostructures (HNs) electrode. The core/shell Fe-Ni/Fe{sub 2}O{sub 3}-NiO hybrid nanostructures have been fabricated through a two step method (nanowire fabrication and their controlled oxidation). The 1D hybrid nanostructure consists of highly porous shell layer (redox active materials NiO and Fe{sub 2}O{sub 3}) and the conductive core (FeNi nanowire). Thus, the highly porous shell layer allows facile electrolyte diffusion as well as faster redox reaction kinetics; whereas the conductive FeNi nanowire core provides the proficient express way for electrons to travel to the current collector,more » which helps in the superior electrochemical performance. The core/shell Fe-Ni/Fe{sub 2}O{sub 3}-NiO hybrid nanostructures electrode based supercapacitor shows very good electrochemical performances in terms of high specific capacitance nearly 1415 F g{sup −1} at a current density of 2.5 A g{sup −1}, excellent cycling stability and rate capability. The high quality electrochemical performance of core/shell hybrid nanostructures electrode shows its potential as an alternative electrode for forthcoming supercapacitor devices.« less

Enhanced blue responses in nanostructured Si solar cells by shallow doping

NASA Astrophysics Data System (ADS)

Cheon, Sieun; Jeong, Doo Seok; Park, Jong-Keuk; Kim, Won Mok; Lee, Taek Sung; Lee, Heon; Kim, Inho

2018-03-01

Optimally designed Si nanostructures are very effective for light trapping in crystalline silicon (c-Si) solar cells. However, when the lateral feature size of Si nanostructures is comparable to the junction depth of the emitter, dopant diffusion in the lateral direction leads to excessive doping in the nanostructured emitter whereby poor blue responses arise in the external quantum efficiency (EQE). The primary goal of this study is to find the correlation of emitter junction depth and carrier collection efficiency in nanostructured c-Si solar cells in order to enhance the blue responses. We prepared Si nanostructures of nanocone shape by colloidal lithography, with silica beads of 520 nm in diameter, followed by a reactive ion etching process. c-Si solar cells with a standard cell architecture of an Al back surface field were fabricated varying the emitter junction depth. We varied the emitter junction depth by adjusting the doping level from heavy doping to moderate doping to light doping and achieved greatly enhanced blue responses in EQE from 47%-92% at a wavelength of 400 nm. The junction depth analysis by secondary ion mass-spectroscopy profiling and the scanning electron microscopy measurements provided us with the design guide of the doping level depending on the nanostructure feature size for high efficiency nanostructured c-Si solar cells. Optical simulations showed us that Si nanostructures can serve as an optical resonator to amplify the incident light field, which needs to be considered in the design of nanostructured c-Si solar cells.

Aptamer-integrated DNA nanostructures for biosensing, bioimaging and cancer therapy.

PubMed

Meng, Hong-Min; Liu, Hui; Kuai, Hailan; Peng, Ruizi; Mo, Liuting; Zhang, Xiao-Bing

2016-05-03

The combination of nanostructures with biomolecules leading to the generation of functional nanosystems holds great promise for biotechnological and biomedical applications. As a naturally occurring biomacromolecule, DNA exhibits excellent biocompatibility and programmability. Also, scalable synthesis can be readily realized through automated instruments. Such unique properties, together with Watson-Crick base-pairing interactions, make DNA a particularly promising candidate to be used as a building block material for a wide variety of nanostructures. In the past few decades, various DNA nanostructures have been developed, including one-, two- and three-dimensional nanomaterials. Aptamers are single-stranded DNA or RNA molecules selected by Systematic Evolution of Ligands by Exponential Enrichment (SELEX), with specific recognition abilities to their targets. Therefore, integrating aptamers into DNA nanostructures results in powerful tools for biosensing and bioimaging applications. Furthermore, owing to their high loading capability, aptamer-modified DNA nanostructures have also been altered to play the role of drug nanocarriers for in vivo applications and targeted cancer therapy. In this review, we summarize recent progress in the design of aptamers and related DNA molecule-integrated DNA nanostructures as well as their applications in biosensing, bioimaging and cancer therapy. To begin with, we first introduce the SELEX technology. Subsequently, the methodologies for the preparation of aptamer-integrated DNA nanostructures are presented. Then, we highlight their applications in biosensing and bioimaging for various targets, as well as targeted cancer therapy applications. Finally, we discuss several challenges and further opportunities in this emerging field.

Shape-Controlled Synthesis of Au Nanostructures Using EDTA Tetrasodium Salt and Their Photothermal Therapy Applications

PubMed Central

Jang, Youngjin; Lee, Nohyun; Kim, Jeong Hyun; Piao, Yuanzhe

2018-01-01

Tuning the optical properties of Au nanostructures is of paramount importance for scientific interest and has a wide variety of applications. Since the surface plasmon resonance properties of Au nanostructures can be readily adjusted by changing their shape, many approaches for preparing Au nanostructures with various shapes have been reported to date. However, complicated steps or the addition of several reagents would be required to achieve shape control of Au nanostructures. The present work describes a facile and effective shape-controlled synthesis of Au nanostructures and their photothermal therapy applications. The preparation procedure involved the reaction of HAuCl4 and ethylenediaminetetraacetic acid (EDTA) tetrasodium salt, which acted as a reducing agent and ligand, at room temperature without the need for any toxic reagent or additives. The morphology control from spheres to branched forms and nanowire networks was easily achieved by varying the EDTA concentration. Detailed investigations revealed that the four carboxylic groups of the EDTA tetrasodium salt are essential for effective growth and stabilization. The produced Au nanowire networks exhibited a broad absorption band in the near-infrared (NIR) region, thereby showing efficient cancer therapeutic performance by inducing the selective photothermal destruction of cancerous glioblastoma cells (U87MG) under NIR irradiation. PMID:29670020

Effective load transfer by a chromium carbide nanostructure in a multi-walled carbon nanotube/copper matrix composite

NASA Astrophysics Data System (ADS)

Cho, Seungchan; Kikuchi, Keiko; Kawasaki, Akira; Kwon, Hansang; Kim, Yangdo

2012-08-01

Multi-walled carbon nanotube (MWCNT) reinforced copper (Cu) matrix composites, which exhibit chromium (Cr) carbide nanostructures at the MWCNT/Cu interface, were prepared through a carbide formation using CuCr alloy powder. The fully densified and oriented MWCNTs dispersed throughout the composites were prepared using spark plasma sintering (SPS) followed by hot extrusion. The tensile strengths of the MWCNT/CuCr composites increased with increasing MWCNTs content, while the tensile strength of MWCNT/Cu composite decreased from that of monolithic Cu. The enhanced tensile strength of the MWCNT/CuCr composites is a result of possible load-transfer mechanisms of the interfacial Cr carbide nanostructures. The multi-wall failure of MWCNTs observed in the fracture surface of the MWCNT/CuCr composites indicates an improvement in the load-bearing capacity of the MWCNTs. This result shows that the Cr carbide nanostructures effectively transferred the tensile load to the MWCNTs during fracture through carbide nanostructure formation in the MWCNT/Cu composite.

Enhanced exchange bias and improved ferromagnetic properties in Permalloy-BiFe0.95Co0.05O3 core-shell nanostructures.

PubMed

Javed, K; Li, W J; Ali, S S; Shi, D W; Khan, U; Riaz, S; Han, X F

2015-12-14

Hybrid core-shell nanostructures consisting of permalloy (Ni80Fe20) and multiferroic(BiFeO3, BFO/BiFe0.95Co0.05O3, BFC) materials were synthesized by a two-step method, based on wet chemical impregnation and subsequent electrodeposition within porous alumina membranes. Structural and magnetic characterizations have been done to investigate doping effect on magnetic properties and exchange bias. The magnetometry analysis revealed significant enhancements of the exchange bias and coercivity in NiFe-BFC core-shell nanostructures as compared with NiFe-BFO core-shell nanostructures. The enhancements can be attributed to the effective reduction of ferromagnet domain sizes between adjacent layers of core-shell structure. It indicates that it is possible to improve properties of multiferroic composites by site-engineering method. Our approach opens a pathway to obtain optimized nanostructured multiferroic composites exhibiting tunable magnetic properties.

Enhanced exchange bias and improved ferromagnetic properties in Permalloy–BiFe0.95Co0.05O3 core–shell nanostructures

PubMed Central

Javed, K.; Li, W. J.; Ali, S. S.; Shi, D. W.; Khan, U.; Riaz, S.; Han, X. F.

2015-01-01

Hybrid core–shell nanostructures consisting of permalloy (Ni80Fe20) and multiferroic(BiFeO3, BFO/BiFe0.95Co0.05O3, BFC) materials were synthesized by a two-step method, based on wet chemical impregnation and subsequent electrodeposition within porous alumina membranes. Structural and magnetic characterizations have been done to investigate doping effect on magnetic properties and exchange bias. The magnetometry analysis revealed significant enhancements of the exchange bias and coercivity in NiFe-BFC core-shell nanostructures as compared with NiFe-BFO core-shell nanostructures. The enhancements can be attributed to the effective reduction of ferromagnet domain sizes between adjacent layers of core-shell structure. It indicates that it is possible to improve properties of multiferroic composites by site-engineering method. Our approach opens a pathway to obtain optimized nanostructured multiferroic composites exhibiting tunable magnetic properties. PMID:26658956

Vitamin D3-Loaded Nanostructured Lipid Carriers as a Potential Approach for Fortifying Food Beverages; in Vitro and in Vivo Evaluation.

PubMed

Mohammadi, Maryam; Pezeshki, Akram; Mesgari Abbasi, Mehran; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2017-04-01

Purpose: Nanostructured lipid carriers (NLCs) composed of solid lipid and oil are a new generation of lipid nanoparticles which have exhibited some merits over traditional used lipid nanoparticles in fortifying food and beverages and nutraceuticals delivery systems such as liposomes and solid lipid nanoparticles. Methods: In this study, Precirol and Compritol as solid lipids, Miglyol and Octyloctanoat as liquid lipids, Tween80, Tween20 and Poloxamer407 as surfactants were used to prepare vitamin D 3 -loaded NLC dispersion using hot homogenization method. The particle size and size distribution for all formulations were evaluated by immediately after production and during a storage period of 60 days. Results: The Precirol-based NLC showed superiority over Compritol-based NLC in the point of physical stability. Results clearly suggested that an optimum concentration of 3% of Poloxamer407 or 2% of Tween20 was sufficient to cover the surface of nanoparticles effectively and prevent agglomeration during the homogenization process. Octyloctanoat was introduced for the first time as a good substituent for Miglyol in the preparation of NLC formulations. The vitamin D 3 Intestinal absorption enhanced by the incorporating in NLCs. Conclusion: It was concluded that NLC showed a promising approach for fortifying beverages by lipophilic nutraceuticals such as vitamin D.

Vitamin D3-Loaded Nanostructured Lipid Carriers as a Potential Approach for Fortifying Food Beverages; in Vitro and in Vivo Evaluation

PubMed Central

Mohammadi, Maryam; Pezeshki, Akram; Mesgari Abbasi, Mehran; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2017-01-01

Purpose: Nanostructured lipid carriers (NLCs) composed of solid lipid and oil are a new generation of lipid nanoparticles which have exhibited some merits over traditional used lipid nanoparticles in fortifying food and beverages and nutraceuticals delivery systems such as liposomes and solid lipid nanoparticles. Methods: In this study, Precirol and Compritol as solid lipids, Miglyol and Octyloctanoat as liquid lipids, Tween80, Tween20 and Poloxamer407 as surfactants were used to prepare vitamin D3-loaded NLC dispersion using hot homogenization method. The particle size and size distribution for all formulations were evaluated by immediately after production and during a storage period of 60 days. Results: The Precirol-based NLC showed superiority over Compritol-based NLC in the point of physical stability. Results clearly suggested that an optimum concentration of 3% of Poloxamer407 or 2% of Tween20 was sufficient to cover the surface of nanoparticles effectively and prevent agglomeration during the homogenization process. Octyloctanoat was introduced for the first time as a good substituent for Miglyol in the preparation of NLC formulations. The vitamin D3 Intestinal absorption enhanced by the incorporating in NLCs. Conclusion: It was concluded that NLC showed a promising approach for fortifying beverages by lipophilic nutraceuticals such as vitamin D. PMID:28507938

Plasmonic nanostructures for bioanalytical applications of SERS

NASA Astrophysics Data System (ADS)

Kahraman, Mehmet; Wachsmann-Hogiu, Sebastian

2016-03-01

Surface-enhanced Raman scattering (SERS) is a potential analytical technique for the detection and identification of chemicals and biological molecules and structures in the close vicinity of metallic nanostructures. We present a novel method to fabricate tunable plasmonic nanostructures and perform a comprehensive structural and optical characterization of the structures. Spherical latex particles are uniformly deposited on glass slides and used as templates to obtain nanovoid structures on polydimethylsiloxane surfaces. The diameter and depth of the nanovoids are controlled by the size of the latex particles. The nanovoids are coated with a thin Ag layer for fabrication of uniform plasmonic nanostructures. Structural characterization of the surfaces is performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Optical properties of these plasmonic nanostructures are evaluated via UV/Vis spectroscopy, and SERS. The sample preparation step is the key point to obtain strong and reproducible SERS spectra from the biological structures. When the colloidal suspension is used as a SERS substrate for the protein detection, the electrostatic interaction of the proteins with the nanoparticles is described by the nature of their charge status, which influences the aggregation properties such as the size and shape of the aggregates, which is critical for the SERS experiment. However, when the solid SERS substrates are fabricated, SERS signal of the proteins that are background free and independent of the protein charge. Pros and cons of using plasmonic nano colloids and nanostructures as SERS substrate will be discussed for label-free detection of proteins using SERS.

Fabrication of 3D nano-structures using reverse imprint lithography.

PubMed

Han, Kang-Soo; Hong, Sung-Hoon; Kim, Kang-In; Cho, Joong-Yeon; Choi, Kyung-Woo; Lee, Heon

2013-02-01

In spite of the fact that the fabrication process of three-dimensional nano-structures is complicated and expensive, it can be applied to a range of devices to increase their efficiency and sensitivity. Simple and inexpensive fabrication of three-dimensional nano-structures is necessary. In this study, reverse imprint lithography (RIL) with UV-curable benzylmethacrylate, methacryloxypropyl terminated poly-dimethylsiloxane (M-PDMS) resin and ZnO-nano-particle-dispersed resin was used to fabricate three-dimensional nano-structures.UV-curable resins were placed between a silicon stamp and a PVA transfer template, followed by a UV curing process. Then, the silicon stamp was detached and a 2D pattern layer was transferred to the substrate using diluted UV-curable glue. Consequently, three-dimensional nano-structures were formed by stacking the two-dimensional nano-patterned layers. RIL was applied to a light-emitting diode (LED) to evaluate the optical effects of a nano-patterned layer. As a result, the light extraction of the patterned LED was increased by about 12% compared to an unpatterned LED.

On-chip surface modified nanostructured ZnO as functional pH sensors

NASA Astrophysics Data System (ADS)

Zhang, Qing; Liu, Wenpeng; Sun, Chongling; Zhang, Hao; Pang, Wei; Zhang, Daihua; Duan, Xuexin

2015-09-01

Zinc oxide (ZnO) nanostructures are promising candidates as electronic components for biological and chemical applications. In this study, ZnO ultra-fine nanowire (NW) and nanoflake (NF) hybrid structures have been prepared by Au-assisted chemical vapor deposition (CVD) under ambient pressure. Their surface morphology, lattice structures, and crystal orientation were investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). Two types of ZnO nanostructures were successfully integrated as gate electrodes in extended-gate field-effect transistors (EGFETs). Due to the amphoteric properties of ZnO, such devices function as pH sensors. We found that the ultra-fine NWs, which were more than 50 μm in length and less than 100 nm in diameter, performed better in the pH sensing process than NW-NF hybrid structures because of their higher surface-to-volume ratio, considering the Nernst equation and the Gouy-Chapman-Stern model. Furthermore, the surface coating of (3-Aminopropyl)triethoxysilane (APTES) protects ZnO nanostructures in both acidic and alkaline environments, thus enhancing the device stability and extending its pH sensing dynamic range.

The effect of thermal oxidation on the luminescence properties of nanostructured silicon.

PubMed

Liu, Lijia; Sham, Tsun-Kong

2012-08-06

Herein is reported a detailed study of the luminescence properties of nanostructured Si using X-ray excited optical luminescence (XEOL) in combination with X-ray absorption near-edge structures (XANES). P-type Si nanowires synthesized via electroless chemical etching from Si wafers of different doping levels and porous Si synthesized using electrochemical method are examined under X-ray excitation across the Si K-, L(3,2) -, and O K-edges. It is found that while as-prepared Si nanostructures are weak light emitters, intense visible luminescence is observed from thermally oxidized Si nanowires and porous Si. The luminescence mechanism of Si upon oxidation is investigated by oxidizing nanostructured Si at different temperatures. Interestingly, the two luminescence bands observed show different response with the variation of absorption coefficient upon Si and O core-electron excitation in elemental silicon and silicon oxide. A correlation between luminescence properties and electronic structures is thus established. The implications of the finding are discussed in terms of the behavior of the oxygen deficient center (OCD) and non-bridging oxygen hole center (NBOHC). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of electrospun nanofibers alignment on the synthesis of one-dimensional silicon carbide nanostructure

NASA Astrophysics Data System (ADS)

Hooshyar, Ali; Kokabi, Mehrdad

2018-01-01

One-dimensional silicon carbide (1D SiC) nanostructure has shown unusual properties such as extremely high strength, good flexibility, fracture toughness, wide band gap ( 3.2eV), large breakdown electric field strength (>2 MV cm-1, 10 times that of silicon), and inverse Hall-Petch effect. Because of these advantages, 1D SiC nanomaterial has gained extensive attention on the wide range of applications in microelectronics, optoelectronics, nanocomposites, and catalyst supports. Many methods have been used for the synthesis of 1D SiC nanostructures such as chemical vapor deposition, carbon nanotube-confined reaction, laser ablation, high-frequency induction heating, and arc discharge. However, these methods have also some shortcomings such as using catalyst, high-cost, low yield, irregular geometry and impurity. In this work, electrospinning was used to prepare aligned PVA/SiO2 composite nanofibers and the effect of fiber alignment on the production efficiency and quality of 1D SiC nanostructure was investigated. For this purpose, aligned electrospun nanofibers, as the desirable precursor, were put in a tube furnace and heated up to 1250°C under a controlled program in an inert atmosphere. Finally, the grown 1D SiC nanostructure product was characterized using SEM, XRD, and FTIR. The results confirmed the successful synthesis of pure crystalline1D β-SiC nanostructure with high yield, more regular, and metal catalyst-free.

Electrodes synthesized from carbon nanostructures coated with a smooth and conformal metal adlayer

DOEpatents

Adzic, Radoslav; Harris, Alexander

2014-04-15

High-surface-area carbon nanostructures coated with a smooth and conformal submonolayer-to-multilayer thin metal films and their method of manufacture are described. The preferred manufacturing process involves the initial oxidation of the carbon nanostructures followed by a surface preparation process involving immersion in a solution with the desired pH to create negative surface dipoles. The nanostructures are subsequently immersed in an alkaline solution containing a suitable quantity of non-noble metal ions which adsorb at surface reaction sites. The metal ions are then reduced via chemical or electrical means. The nanostructures are exposed to a solution containing a salt of one or more noble metals which replace adsorbed non-noble surface metal atoms by galvanic displacement. The process can be controlled and repeated to obtain a desired film coverage. The resulting coated nanostructures may be used, for example, as high-performance electrodes in supercapacitors, batteries, or other electric storage devices.

La 1-x Ca x MnO 3 semiconducting nanostructures: morphology and thermoelectric properties.

PubMed

Culebras, Mario; Torán, Raquel; Gómez, Clara M; Cantarero, Andrés

2014-01-01

Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1-x Ca x MnO 3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content.

A study on photoelectrochemical properties of ZnO@ZnS nanostructures synthesized via facile ion-exchange approach

NASA Astrophysics Data System (ADS)

Sharma, Akash; Sahoo, Pooja; Thangavel, R.

2018-05-01

In this work, ZnO nanorods (NRs) were fabricated, on cleaned ITO substrates by using sol-gel spin coating followed by hydrothermal technique. In order to coat zinc sulphide (ZnS) layers on the earlier prepared NRs a facile ion-exchange approach was adopted. The ZnO@ZnS nanostructures so prepared were characterised by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-visible spectroscopy and photoelectrochemical study. XRD spectra confirmed the hexagonal wurtzite structure of all the samples along with preferential c-axis orientation. Further it was also observed from the FESEM images that sulfidation process doesn't affect the structure of ZnO NRs arrays. From the absorption spectra it can be clearly observed that the light absorbing property has increased in within the visible range due to the formation of ZnS layer on the ZnO nanostructures, which is not possible for either of the material individually. The cyclic voltammetry results indicates the enhancement in photocurrent density after illumination for the synthesized nanostructures. The electrocatalytic behaviour of ZnO@ZnS electrodes have been studied using a 3-electrode system in presence of 0.1M NaOH electrolyte solution with respect to an Ag/AgCl reference electrode.

Metallic nanospheres embedded in nanowires initiated on nanostructures and methods for synthesis thereof

DOEpatents

Zaidi, Saleem [Albuquerque, NM; Tringe, Joseph W [Walnut Creek, CA; Vanamu, Ganesh [Sunnyvale, CA; Prinja, Rajiv [Albuquerque, NM

2012-01-10

A nanostructure includes a nanowire having metallic spheres formed therein, the spheres being characterized as having at least one of about a uniform diameter and about a uniform spacing there between. A nanostructure in another embodiment includes a substrate having an area with a nanofeature; and a nanowire extending from the nanofeature, the nanowire having metallic spheres formed therein, the spheres being characterized as having at least one of about a uniform diameter and about a uniform spacing there between. A method for forming a nanostructure is also presented. A method for reading and writing data is also presented. A method for preparing nanoparticles is also presented.

Chemical Sensors Based on Metal Oxide Nanostructures

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

2006-01-01

This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

Copper, gold, and silver decorated magnetic core-polymeric shell nanostructures for destruction of pathogenic bacteria

NASA Astrophysics Data System (ADS)

Padervand, Mohsen; Karanji, Ahmad Kiani; Elahifard, Mohammad Reza

2017-05-01

Fe3O4 magnetic nanoparticles (MNPs) were prepared by co-precipitation method. The nanoparticles were silica coated using TEOS, and then modified by the polymeric layers of polypropylene glycol (PPG) and polyethylene glycol (PEG). Finally, the core-shell samples were decorated with Ag, Au, and Cu nanoparticles. The products were characterized by vibrating sample magnetometry (VSM), TGA, SEM, XRD, and FTIR methods. The antibacterial activity of the prepared samples was evaluated in inactivation of E. coli and S. aureus microorganisms, representing the Gram-negative and Gram-positive species, respectively. The effect of solid dosage, bacteria concentration and type of polymeric modifier on the antibacterial activity was investigated. TEM images of the bacteria were recorded after the treatment time and according to the observed changes in the cell wall, the mechanism of antibacterial action was discussed. The prepared nanostructures showed high antibacterial activity against both Gram-negative and Gram-positive bacteria. This was due to the leaching of metal ions which subsequently led to the lysis of bacteria. A theoretical investigation was also done by studying the interaction of loaded metals with the nucleotide components of the microorganism DNA, and the obtained results were used to explain the experimental data. Finally, based on the observed inactivation curves, we explain the antibacterial behavior of the prepared nanostructures mathematically.

A hierarchical nanostructure consisting of amorphous MnO 2, Mn 3O 4 nanocrystallites, and single-crystalline MnOOH nanowires for supercapacitors

NASA Astrophysics Data System (ADS)

Hu, Chi-Chang; Hung, Ching-Yun; Chang, Kuo-Hsin; Yang, Yi-Lin

In this communication, a porous hierarchical nanostructure consisting of amorphous MnO 2 (a-MnO 2), Mn 3O 4 nanocrystals, and single-crystalline MnOOH nanowires is designed for the supercapacitor application, which is prepared by a simple two-step electrochemical deposition process. Because of the gradual co-transformation of Mn 3O 4 nanocrystals and a-MnO 2 nanorods into an amorphous manganese oxide, the cycle stability of a-MnO 2 is obviously enhanced by adding Mn 3O 4. This unique ternary oxide nanocomposite with 100-cycle CV activation exhibits excellent capacitive performances, i.e., excellent reversibility, high specific capacitances (470 F g -1 in CaCl 2), high power property, and outstanding cycle stability. The highly porous microstructures of this composite before and after the 10,000-cycle CV test are examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Hetero-metal cation control of CuO nanostructures and their high catalytic performance for CO oxidation

NASA Astrophysics Data System (ADS)

Huang, Hongwen; Zhang, Liqiang; Wu, Kewei; Yu, Qing; Chen, Ru; Yang, Hangsheng; Peng, Xinsheng; Ye, Zhizhen

2012-11-01

A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous CuO quasi-monocrystalline nanosheets prepared at 25 °C with a thickness of ca. 10 nm and large specific surface area of 80.32 m2 g-1 is investigated intensively. These CuO nanosheets demonstrate a superior catalytic activity for CO oxidation, with features of high CO conversion efficiency (47.77 mmolCO g-1CuO h-1 at 200 °C), which is close to that reported for previously investigated supported-CuO catalysts, and a low apparent activation energy Ea (53.3 kJ mol-1).A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous Cu

Reusable three-dimensional nanostructured substrates for surface-enhanced Raman scattering.

PubMed

Zhu, Zhendong; Li, Qunqing; Bai, Benfeng; Fan, Shoushan

2014-01-13

To date, fabricating three-dimensional (3D) nanostructured substrate with small nanogap was a laborious challenge by conventional fabrication techniques. In this article, we address a simple, low-cost, large-area, and spatially controllable method to fabricate 3D nanostructures, involving hemisphere, hemiellipsoid, and pyramidal pits based on nanosphere lithography (NSL). These 3D nanostructures were used as surface-enhanced Raman scattering (SERS) substrates of single Rhodamine 6G (R6G) molecule. The average SERS enhancement factor achieved up to 1011. The inevitably negative influence of the adhesion-promoting intermediate layer of Cr or Ti was resolved by using such kind of 3D nanostructures. The nanostructured quartz substrate is a free platform as a SERS substrate and is nondestructive when altering with different metal films and is recyclable, which avoids the laborious and complicated fabricating procedures.

Reusable three-dimensional nanostructured substrates for surface-enhanced Raman scattering

PubMed Central

2014-01-01

To date, fabricating three-dimensional (3D) nanostructured substrate with small nanogap was a laborious challenge by conventional fabrication techniques. In this article, we address a simple, low-cost, large-area, and spatially controllable method to fabricate 3D nanostructures, involving hemisphere, hemiellipsoid, and pyramidal pits based on nanosphere lithography (NSL). These 3D nanostructures were used as surface-enhanced Raman scattering (SERS) substrates of single Rhodamine 6G (R6G) molecule. The average SERS enhancement factor achieved up to 1011. The inevitably negative influence of the adhesion-promoting intermediate layer of Cr or Ti was resolved by using such kind of 3D nanostructures. The nanostructured quartz substrate is a free platform as a SERS substrate and is nondestructive when altering with different metal films and is recyclable, which avoids the laborious and complicated fabricating procedures. PMID:24417892

Soot Combustion over Nanostructured Ceria with Different Morphologies

PubMed Central

Zhang, Wen; Niu, Xiaoyu; Chen, Liqiang; Yuan, Fulong; Zhu, Yujun

2016-01-01

In this study, nano-structure ceria with three different morphologies (nanorod, nanoparticle and flake) have been prepared by hydrothermal and solvothermal methods. The ceria samples were deeply characterized by XRD, SEM, TEM, H2-TPR, XPS and in-situ DRIFTS, and tested for soot combustion in absence/presence NO atmospheres under loose and tight contact conditions. The prepared ceria samples exhibit excellent catalytic activities, especially, the CeO2 with nanorod (Ce-R) shows the best catalytic activity, for which the peak temperature of soot combustion (Tm) is about 500 and 368 °C in loose and tight contact conditions, respectively. The catalytic activity for Ce-R is higher than that of the reported CeO2 catalysts and reaches a level that of precious metals. The characterization results reveal that the maximal amounts of adsorbed oxygen species on the surface of the nanostructure Ce-R catalyst should be the crucial role to decide the catalytic soot performance. High BET surface area may also be a positive effect on soot oxidation activity under loose contact conditions. PMID:27353143

Detection of gain enhancement in laser-induced fluorescence of rhodamine B lasing dye by silicon dioxide nanostructures-coated cavity

NASA Astrophysics Data System (ADS)

Al-Tameemi, Mohammed N. A.

2018-03-01

In this work, nanostructured silicon dioxide films are deposited by closed-field unbalanced direct-current (DC) reactive magnetron sputtering technique on two sides of quartz cells containing rhodamine B dye dissolved in ethanol with 10‒5 M concentration as a random gain medium. The preparation conditions are optimized to prepare highly pure SiO2 nanostructures with a minimum particle size of about 20 nm. The effect of SiO2 films as external cavity for the random gain medium is determined by the laser-induced fluorescence of this medium, and an increase of about 200% in intensity is observed after the deposition of nanostructured SiO2 thin films on two sides of the dye cell.

Fabrication of hollow boron-doped diamond nanostructure via electrochemical corrosion of a tungsten oxide template.

PubMed

Lim, Young-Kyun; Lee, Eung-Seok; Lee, Choong-Hyun; Lim, Dae-Soon

2018-08-10

In the study, a hollow boron-doped diamond (BDD) nanostructure electrode is fabricated to increase the reactive surface area for electrochemical applications. Tungsten oxide nanorods are deposited on the silicon substrate as a template by the hot filament chemical vapor deposition (HFCVD) method. The template is coated with a 100 nm BDD layer deposited by HFCVD to form a core-shell nanostructure. The WO x core is finally electrochemically dissolved to form hollow BDD nanostructure. The fabricated hollow BDD nanostructure electrode is investigated via scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The specific surface areas of the electrodes were analyzed and compared by using Brunauer-Emmett-Teller method. Furthermore, cyclic voltammetry and chronocoulometry are used to investigate the electrochemical characteristics and the reactive surface area of the as-prepared hollow BDD nanostructure electrode. A hollow BDD nanostructure electrode exhibits a reactive area that is 15 times that of a planar BDD thin electrode.

Tetrazole amphiphile inducing growth of conducting polymers hierarchical nanostructures and their electromagnetic absorption properties

NASA Astrophysics Data System (ADS)

Xie, Aming; Sun, Mengxiao; Zhang, Kun; Xia, Yilu; Wu, Fan

2018-05-01

Conducting polymers (CPs) at nano scales endow materials with special optical, electrical, and magnetic properties. The crucial factor to construct and regulate the micro-structures of CPs is the inducing reagent, particular in its chemical structure, such active sites, self-assembling properties. In this paper, we design and synthesize an amphiphile bearing tetrazole moiety on its skeleton, and use this amphiphile as an inducing reagent to prepare and regulate the micro-structures of a series of CPs including polypyrrole, polyaniline, poly(3,4-ethylenedioxythiophene) and poly(p-phenylenediamine). Because of the unique electric properties of CPs and size effect, we next explored the electromagnetic absorption performances of these CPs nanostructures. A synergetic combination of electric loss and magnetic loss is used to explain the absorption mechanism of these CPs nano-structures.

Importance of polypyrrole in constructing 3D hierarchical carbon nanotube@MnO2 perfect core-shell nanostructures for high-performance flexible supercapacitors

NASA Astrophysics Data System (ADS)

Zhou, Jinyuan; Zhao, Hao; Mu, Xuemei; Chen, Jiayi; Zhang, Peng; Wang, Yaling; He, Yongmin; Zhang, Zhenxing; Pan, Xiaojun; Xie, Erqing

2015-08-01

This study reports the preparation of 3D hierarchical carbon nanotube (CNT) @MnO2 core-shell nanostructures under the assistance of polypyrrole (PPy). The as-prepared CNT@PPy@MnO2 core-shell structures show a perfect coating of MnO2 on each CNT and, more importantly, a robust bush-like pseudocapacitive shell to effectively increase the specific surface area and enhance the ion accessibility. As expected, a high specific capacity of 490-530 F g-1 has been achieved from CNT@PPy@MnO2 single electrodes. And about 98.5% of the capacity is retained after 1000 charge/discharge cycles at a current density of 5 A g-1. Furthermore, the assembled asymmetric CNT@PPy@MnO2//AC capacitors show the maximum energy density of 38.42 W h kg-1 (2.24 mW h cm-3) at a power density of 100 W kg-1 (5.83 mW cm-3), and they maintain 59.52% of the initial value at 10 000 W kg-1 (0.583 W cm-3). In addition, the assembled devices show high cycling stabilities (89.7% after 2000 cycles for asymmetric and 87.2% for symmetric), and a high bending stability (64.74% after 200 bending tests). This ability to obtain high energy densities at high power rates while maintaining high cycling stability demonstrates that this well-designed structure could be a promising electrode material for high-performance supercapacitors.This study reports the preparation of 3D hierarchical carbon nanotube (CNT) @MnO2 core-shell nanostructures under the assistance of polypyrrole (PPy). The as-prepared CNT@PPy@MnO2 core-shell structures show a perfect coating of MnO2 on each CNT and, more importantly, a robust bush-like pseudocapacitive shell to effectively increase the specific surface area and enhance the ion accessibility. As expected, a high specific capacity of 490-530 F g-1 has been achieved from CNT@PPy@MnO2 single electrodes. And about 98.5% of the capacity is retained after 1000 charge/discharge cycles at a current density of 5 A g-1. Furthermore, the assembled asymmetric CNT@PPy@MnO2//AC capacitors show the

Synthesis of nanostructured materials in inverse miniemulsions and their applications.

PubMed

Cao, Zhihai; Ziener, Ulrich

2013-11-07

Polymeric nanogels, inorganic nanoparticles, and organic-inorganic hybrid nanoparticles can be prepared via the inverse miniemulsion technique. Hydrophilic functional cargos, such as proteins, DNA, and macromolecular fluoresceins, may be conveniently encapsulated in these nanostructured materials. In this review, the progress of inverse miniemulsions since 2000 is summarized on the basis of the types of reactions carried out in inverse miniemulsions, including conventional free radical polymerization, controlled/living radical polymerization, polycondensation, polyaddition, anionic polymerization, catalytic oxidation reaction, sol-gel process, and precipitation reaction of inorganic precursors. In addition, the applications of the nanostructured materials synthesized in inverse miniemulsions are also reviewed.

The Development of Metal Oxide Chemical Sensing Nanostructures

NASA Technical Reports Server (NTRS)

Hunter, G. W.; VanderWal,R. L.; Xu, J. C.; Evans, L. J.; Berger, G. M.; Kulis, M. J.

2008-01-01

This paper discusses sensor development based on metal oxide nanostructures and microsystems technology. While nanostructures such as nanowires show significant potential as enabling materials for chemical sensors, a number of significant technical challenges remain. This paper discusses development to address each of these technical barriers: 1) Improved contact and integration of the nanostructured materials with microsystems in a sensor structure; 2) Control of nanostructure crystallinity to allow control of the detection mechanism; and 3) Widening the range of gases that can be detected by fabricating multiple nanostructured materials. A sensor structure composed of three nanostructured oxides aligned on a single microsensor has been fabricated and tested. Results of this testing are discussed and future development approaches are suggested. It is concluded that while this work lays the foundation for further development, these are the beginning steps towards realization of repeatable, controlled sensor systems using oxide based nanostructures.

Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films.

PubMed

He, Ziming; Xu, Qingchi; Tan, Timothy Thatt Yang

2011-12-01

TiO(2)-InVO(4) nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO(2)-InVO(4) nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO(4) and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO(2) film, the current TiO(2)-InVO(4) films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell "photo-fixation" was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.

Nanopatterning of magnetic domains: Fe coverage of self-assembled alumina nanostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Qibin; Wang, Bo -Yao; Lin, Wen -Chin

2015-08-19

Nanosized ultrathin magnetic films were prepared by controlling the deposition of Fe onto an oxidized NiAl(001) surface with an alumina nanostructure on it. Because the ultrathin ferromagnetic Fe films on the bare NiAl(001) surface are separated by paramagnetic Fe nanoparticles on the alumina stripes, as determined by scanning electron microscopy with spin analysis, they form rectangular domains with sizes ranging from tens of nanometer to larger than a micrometer. Furthermore, magnetic domain patterning can thus be achieved by controlling the Fe coverage and nanostructured template.

25th anniversary article: hybrid nanostructures based on two-dimensional nanomaterials.

PubMed

Huang, Xiao; Tan, Chaoliang; Yin, Zongyou; Zhang, Hua

2014-04-09

Two-dimensional (2D) nanomaterials, such as graphene and transition metal dichalcogenides (TMDs), receive a lot of attention, because of their intriguing properties and wide applications in catalysis, energy-storage devices, electronics, optoelectronics, and so on. To further enhance the performance of their application, these 2D nanomaterials are hybridized with other functional nanostructures. In this review, the latest studies of 2D nanomaterial-based hybrid nanostructures are discussed, focusing on their preparation methods, properties, and applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanostructures and hydrophilicity influence osseointegration: a biomechanical study in the rabbit tibia.

PubMed

Wennerberg, Ann; Jimbo, Ryo; Stübinger, Stefan; Obrecht, Marcel; Dard, Michel; Berner, Simon

2014-09-01

Implant surface properties have long been identified as an important factor to promote osseointegration. The importance of nanostructures and hydrophilicity has recently been discussed. The aim of this study was to investigate how nanostructures and wettability influence osseointegration and to identify whether the wettability, the nanostructure or both in combination play the key role in improved osseointegration. Twenty-six adult rabbits each received two Ti grade 4 discs in each tibia. Four different types of surface modifications with different wettability and nanostructures were prepared: hydrophobic without nanostructures (SLA), with nanostructures (SLAnano); hydrophilic with two different nanostructure densities (low density: pmodSLA, high density: SLActive). All four groups were intended to have similar chemistry and microroughness. The surfaces were evaluated with contact angle measurements, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and interferometry. After 4 and 8 weeks healing time, pull-out tests were performed. SLA and SLAnano were hydrophobic, whereas SLActive and pmodSLA were super-hydrophilic. No nanostructures were present on the SLA surface, but the three other surface modifications clearly showed the presence of nanostructures, although more sparsely distributed on pmodSLA. The hydrophobic samples showed higher carbon contamination levels compared with the hydrophilic samples. After 4 weeks healing time, SLActive implants showed the highest pull-out values, with significantly higher pull-out force than SLA and SLAnano. After 8 weeks, the SLActive implants had the highest pull-out force, significantly higher than SLAnano and SLA. The strongest bone response was achieved with a combination of wettability and the presence of nanostructures (SLActive). © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Silicon nanostructure arrays prepared by single step metal assisted chemical etching from single crystal wafer

NASA Astrophysics Data System (ADS)

Sarkar, Kalyan; Das, Debajyoti

2018-04-01

Arrays of silicon nanostructures have been produced by single step Metal Assisted Chemical Etching (MACE) of single crystal Si-wafers at room temp and normal atmospheric condition. By studying optical and structural properties of the silicon nanowire like structures synthesized by Ag catalyst assisted chemical etching, a significant change in the reflectance spectra has been obtained leading to a gross reduction in reflectance from ˜31% to less than 1%. In comparison with bulk c-Si, the surface areas of the nanostructured samples have been increased significantly with the etching time, leading to an efficient absorption of light, favorable for photovoltaic applications.

Tailoring Co(OH)2 hollow nanostructures via Cu2O template etching for high performance supercapacitors.

PubMed

Yang, Huan; Xie, Jiale; Bao, Shu juan; Li, Chang Ming

2015-11-01

Co(OH)2 hollow nanostructures including cube, octahedron and flower are delicately tailored via a simple and fast one-step Cu2O template etching method. The as-prepared materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscope (FESEM), N2 adsorption-desorption and electrochemical methods and X-ray photoelectron spectroscopy (XPS). In particular, the supercapacitive behaviors of the as-prepared materials were investigated to explore relation of capacitance versus nanostructure. Results indicate that the as-prepared Co(OH)2 samples inherit the size and shape of the Cu2O templates but with an inside hollow, and the differently nanostructured Co(OH)2 exhibits different capacitive behaviors. Among various morphologies, the flower Co(OH)2 has the largest specific capacitance of 1350 F/g, while octahedron Co(OH)2 has the smallest one of 986.4 F/g. This is mainly because the flower Co(OH)2 not only has the largest available surface area, but also offers the fast interfacial electron transfer for higher pseudocapacitance and enhanced electrolyte ion diffusion rate for high power density, which is supported by both theoretical calculation, measured BET data and ac impedance measurements. This work may provide a vivid example to rationally design a nanostructure and further explore its fundamental insights for high performance supercapacitors. Copyright © 2015 Elsevier Inc. All rights reserved.

Polymer Self-Assembly into Unique Fractal Nanostructures in Solution by a One-Shot Synthetic Procedure.

PubMed

Shin, Suyong; Gu, Ming-Long; Yu, Chin-Yang; Jeon, Jongseol; Lee, Eunji; Choi, Tae-Lim

2018-01-10

A fractal nanostructure having a high surface area is potentially useful in sensors, catalysts, functional coatings, and biomedical and electronic applications. Preparation of fractal nanostructures on solid substrates has been reported using various inorganic or organic compounds. However, achieving such a process using polymers in solution has been extremely challenging. Here, we report a simple one-shot preparation of polymer fractal nanostructures in solution via an unprecedented assembly mechanism controlled by polymerization and self-assembly kinetics. This was possible only because one monomer was significantly more reactive than the other, thereby easily forming a diblock copolymer microstructure. Then, the second insoluble block containing poly(p-phenylenevinylene) (PPV) without any side chains spontaneously underwent self-assembly during polymerization by an in situ nanoparticlization of conjugated polymers (INCP) method. The formation of fractal structures in solution was confirmed by various imaging techniques such as atomic force microscopy, transmission electron microscopy (TEM), and cryogenic TEM. The diffusion-limited aggregation theory was adopted to explain the branching patterns of the fractal nanostructures according to the changes in polymerization conditions such as the monomer concentration and the presence of additives. Finally, after detailed kinetic analyses, we proposed a plausible mechanism for the formation of unique fractal nanostructures, where the gradual formation and continuous growth of micelles in a chain-growth-like manner were accounted for.

Preparation of micro/nanostructure TiO2 spheres by controlling pollen as hard template and soft template.

PubMed

Yang, Xiaohui; Xu, Bin; Zhang, Xuehong; Song, Xiuqin; Chen, Rufen

2014-09-01

In this paper, micro/nanostructure TiO2 spheres were synthesized by a sunflower pollen induced and self-assembly mineralization process, in which a titania precursor and pollen reacted in one-pot at normal pressure. In this paper, the bio-template advantage, as hard and soft template is fully demonstrated. The superiority of our synthesis is that we not only can control pollen as hard template, but also can control it as soft template only by changing reactions temperature. Under 80 degrees C of water bath, TiO2 microspheres which replicated the morphology of pollen were prepared by controlling pollen as hard template. Under 100 degrees C, hierarchical TiO2 spheres with complicated morphology, different from pollen template, were synthesized by using pollen as soft template. At the same time, judicious choice of the amount of pollen affords the synthesis of hierarchical structures spheres with adjustable morphology and crystal structure. The morphology can be tuned from microspheres constructed from TiO2 nanorods to nanospheres constructed from TiO2 nanoparticles, and the crystal structure can be tuned from rutile to anatase. More over this anatase phase can be keep better even at high temperature of 1000 degrees C. The as-prepared micro/nano structure photocatalysts not only have high photocatalytic activities, but also have good separability and reuse performance.

Novel ascorbic acid based ionic liquids for the in situ synthesis of quasi-spherical and anisotropic gold nanostructures in aqueous medium.

PubMed

Dinda, Enakshi; Si, Satyabrata; Kotal, Atanu; Mandal, Tarun K

2008-01-01

A series of newly designed ascorbic acid based room temperature ionic liquids were successfully used to prepare quasi-spherical and anisotropic gold nanostructures in an aqueous medium at ambient temperature. The synthesis of these room temperature ionic liquids involves, first, the preparation of a 1-alkyl (such as methyl, ethyl, butyl, hexyl, octyl, and decyl) derivative of 3-methylimidazolium hydroxide followed by the neutralization of the derivatised product with ascorbic acid. These ionic liquids show significantly better thermal stability and their glass transition temperature (Tg) decreases with increasing alkyl chain length. The ascorbate counter anion of these ionic liquids acts as a reducing agent for HAuCl4 to produce metallic gold and the alkylated imidazolium counter cation acts as a capping/shape-directing agent. It has been found that the nature of the ionic liquids and the mole ratio of ionic liquid to HAuCl4 has a significant effect on the morphology of the formed gold nanostructures. If an equimolar mixture of ionic liquid and HAuCl4 is used, predominantly anisotropic gold nanostructures are formed and by varying the alkyl chain length attached to imidazolium cation of the ionic liquids, various particle morphologies can formed, such as quasispherical, raspberry-like, flakes or dendritic. A probable formation mechanism for such anisotropic gold nanostructures has been proposed, which is based on the results of some control experiments.

Development of nanostructured ZnO thin film via electrohydrodynamic atomization technique and its photoconductivity characteristics.

PubMed

Duraisamy, Navaneethan; Kwon, Ki Rin; Jo, Jeongdai; Choi, Kyung-Hyun

2014-08-01

This article presents the non-vacuum technique for the preparation of nanostructured zinc oxide (ZnO) thin film on glass substrate through electrohydrodynamic atomization (EHDA) technique. The detailed process parameters for achieving homogeneous ZnO thin films are clearly discussed. The crystallinity and surface morphology of ZnO thin film are investigated by X-ray diffraction and field emission scanning electron microscopy. The result shows that the deposited ZnO thin film is oriented in the wurtzite phase with void free surface morphology. The surface roughness of deposited ZnO thin film is found to be ~17.8 nm. The optical properties of nanostructured ZnO thin films show the average transmittance is about 90% in the visible region and the energy band gap is found to be 3.17 eV. The surface chemistry and purity of deposited ZnO thin films are analyzed by fourier transform infrared and X-ray photoelectron spectroscopy, conforming the presence of Zn-O in the deposited thin films without any organic moiety. The photocurrent measurement of nanostructured ZnO thin film is examined in the presence of UV light illumination with wavelength of 365 nm. These results suggest that the deposited nanostructured ZnO thin film through EHDA technique possess promising applications in the near future.

Superhydrophilic nanostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Samuel S; Zormpa, Vasileia; Chen, Xiaobo

2015-05-12

An embodiment of a superhydrophilic nanostructure includes nanoparticles. The nanoparticles are formed into porous clusters. The porous clusters are formed into aggregate clusters. An embodiment of an article of manufacture includes the superhydrophilic nanostructure on a substrate. An embodiment of a method of fabricating a superhydrophilic nanostructure includes applying a solution that includes nanoparticles to a substrate. The substrate is heated to form aggregate clusters of porous clusters of the nanoparticles.

Mechanical design of DNA nanostructures.

PubMed

Castro, Carlos E; Su, Hai-Jun; Marras, Alexander E; Zhou, Lifeng; Johnson, Joshua

2015-04-14

Structural DNA nanotechnology is a rapidly emerging field that has demonstrated great potential for applications such as single molecule sensing, drug delivery, and templating molecular components. As the applications of DNA nanotechnology expand, a consideration of their mechanical behavior is becoming essential to understand how these structures will respond to physical interactions. This review considers three major avenues of recent progress in this area: (1) measuring and designing mechanical properties of DNA nanostructures, (2) designing complex nanostructures based on imposed mechanical stresses, and (3) designing and controlling structurally dynamic nanostructures. This work has laid the foundation for mechanically active nanomachines that can generate, transmit, and respond to physical cues in molecular systems.

Luminescence studies of laser MBE grown GaN on ZnO nanostructures

NASA Astrophysics Data System (ADS)

Dewan, Sheetal; Tomar, Monika; Kapoor, Ashok K.; Tandon, R. P.; Gupta, Vinay

2017-08-01

GaN films have been successfully fabricated using Laser Molecular Beam Epitaxy (LMBE) technique on bare c-plane sapphire substrate and ZnO nanostructures (NS) decorated Si (100) substrates. The ZnO nanostructures were grown on Si (100) substrate using high pressure assisted Pulsed laser deposition technique in inert gas ambience. Discrete nanostructured morphology of ZnO was obtained using the PLD growth on Si substrates. Photoluminescence studies performed on the prepared GaN/Sapphire and GaN/ZnO-NS/Si systems, revealed a significant PL enhancement in case of GaN/ZnO-NS/Si system compared to the former. The hexagonal nucleation sites provided by the ZnO nanostructures strategically enhanced the emission of GaN film grown by Laser MBE Technique at relatively lower temperature of 700°C. The obtained results are attractive for the realization of highly luminescent GaN films on Si substrate for photonic devices.

Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gomez, A.; Villanueva, R.; Vie, D.

2013-01-15

Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 10-15 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and themore » nature of the dopant. In addition, Rietveld refinement of the XRD profiles of selected samples allows detecting the coexistence of the tetragonal and the cubic phases for high doping concentration and high thermal treatment temperatures. Raman experiments suggest the presence of both phases also at relatively low treatment temperatures. - Graphical abstract: Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders by thermal decomposition of precursors obtained by freeze-drying, and this synthetic procedure has been scaled up to the 100 g scale. Highlights: Black-Right-Pointing-Pointer Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders. Black-Right-Pointing-Pointer The synthetic method involves the thermal decomposition of precursors obtained by freeze-drying. Black-Right-Pointing-Pointer The temperature of the thermal treatment controls particle sizes. Black-Right-Pointing-Pointer The preparation procedure has been scaled up to the 100 g scale. Black-Right-Pointing-Pointer This method is appropriate for the large-scale industrial preparation of multimetallic systems.« less

Rapid and solvent-free solid-state synthesis and characterization of Zn3V2O8 nanostructures and their phenol red aqueous solution photodegradation

NASA Astrophysics Data System (ADS)

Mazloom, Fatemeh; Masjedi-Arani, Maryam; Salavati-Niasari, Masoud

2017-08-01

Zinc vanadate (Zn3V2O8) nanostructures have been successfully synthesized via simple, rapid and solvent-free solid-state method by using different complex precursors of Zn and NH4VO3 as novel starting materials. Effects of various zinc (II) Schiff base complex precursors and calcination temperatures were investigated to reach optimum condition. It was found that particle size and optical property of the as-prepared products could be greatly influenced via these parameters. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Photoluminescence and ultraviolet-visible (UV-Vis) spectroscopy. The photocatalytic activity of zinc vanadate nano and bulk structures were compared by degradation of phenol red aqueous solution.

Investigation of structural, optical, catalytic, fluorescence studies of eco-friendly synthesized Bi2S3 nanostructures

NASA Astrophysics Data System (ADS)

Ayodhya, Dasari; Veerabhadram, Guttena

2017-02-01

A simple solution phase method has been developed for the synthesis of ribonucleosides capped Bi2S3 nanostructures (NSs) with an average diameter of 15 nm and length of below 100 nm. Transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD) studies revealed that these NSs were grown from a colloidal dispersion of amorphous Bi2S3 particles, which was first formed through a thermal reaction at a temperature of 60 °C. The phase and structure of the Bi2S3 NSs have been identified by using X-ray powder diffraction. The crystal structure had orthorhombic structure. The surface properties and morphology have been investigated using scanning electron microscope (SEM) technique. The N2 sorption-desorption experiments showed that the surface area of the NSs was 6.35 m2 g-1 by Brunauer-Emmett-Teller (BET). The experiments showed that the Bi2S3 NSs prepared in the present work could be used as catalyst for the reduction of SO dye using a reducing agent. It was found that the as-obtained Bi2S3 NSs contributed to the best catalytic activity. Photoluminescence experiments showed a quenching of the Bi2S3 fluorescence with increasing L-cysteine (Cys) content in the solution. Furthermore, the proposed NSs as sensor were employed for the determination of metal ions with satisfactory results.

Morphology dependent catalytic activity of TiO{sub 2} nanostructures towards photodegradation of Rose Bengal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malik, Ritu; Kumar, Ashok; Rana, Pawan S., E-mail: drpawansrana.phy@dcrustm.org

2015-08-28

This work deals with the synthesis of TiO{sub 2} nanostructures using sol-gel and hydrothermal method for evaluating their photodegradation performance towards decolorization of Rose Bengal (RB). A combination of characterization techniques including X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and UV–Vis spectroscopy were utilized to evaluate the structural, morphological and optical properties of the obtained nanostructures. It was observed that the TiO{sub 2} nanoparticles prepared using hydrothermal method were highly crystalline and possess higher band gap value, even when same conditions of temperature, pressure, precursor ratios and solvent amount was kept constant while synthesizing TiO{sub 2} nanostructures viamore » sol-gel method. The obvious effect of porous morphology exhibited by TiO{sub 2} nanoparticles prepared using hydrothermal route is reflected in its decolorization performance whereby 92.5% of the RB dye solution was degraded in 70 min of irradiation time.« less

Solvothermal synthesis of Fe{sub 7}C{sub 3} and Fe{sub 3}C nanostructures with phase and morphology control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Brent; Clifford, Dustin; Carpenter, Everett E., E-mail: aelgendy@vcu.edu, E-mail: ecarpenter2@vcu.edu

A phase transition, from orthorhombic Fe{sub 3}C to hexagonal Fe{sub 7}C{sub 3}, was observed using a wet synthesis mediated by hexadecyltrimethylammonium chloride (CTAC). In this study, CTAC has been shown to control carbide phase, morphology, and size of the iron carbide nanostructures. Fe{sub 7}C{sub 3} hexagonal prisms were formed with an average diameter of 960 nm, the thickness of 150 nm, and Fe{sub 3}C nanostructures with an approximate size of 50 nm. Magnetic studies show ferromagnetic behavior with M{sub s} of 126 emu/g, and H{sub c} of 170 Oe with respect to Fe{sub 7}C{sub 3} and 95 emu/g and 590 Oe with respect to Fe{sub 3}C. Themore » thermal studies using high temperature x-ray diffraction show stability of Fe{sub 7}C{sub 3} up to 500 °C. Upon slow cooling, the Fe{sub 7}C{sub 3} phase is recovered with an intermediate oxide phase occurring around 300 °C. This study has demonstrated a simple route in synthesizing iron carbides for an in depth magnetic study and crystal phase transition study of Fe{sub 7}C{sub 3} at elevated temperatures.« less

A facile approach for the fabrication of 3D flower-like Cu2S nanostructures on brass mesh with temperature-induced wetting transition for efficient oil-water separation

NASA Astrophysics Data System (ADS)

Niu, Lei; Kang, Zhixin

2017-11-01

3D flower-like Cu2S nanostructures on brass meshes have been fabricated for the first time, with a reversible wetting transition and excellent durability. In the present work, we demonstrated a simple and environmentally-benign method to fabricate the nanostructures utilizing an electrolyte containing CuSO4·5H2O, EDTA-2Na and CH3CSNH2. The superhydrophobicity was achieved by drying thoroughly at 200 °C, instead of using low surface energy materials. After annealing at 300 °C for 6 min, the superhydrophobic surface was oxidized and became superhydrophilic. However, the superhydrophobicity can be restored by heating at 200 °C for several hours. In simpler terms, the reversible wetting transition is responded to the temperature. Scanning electron microscopy, X-ray diffractometer, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize the surfaces and analyze the wetting transition mechanism. Furthermore, different kinds of oily sewages were separated by as-prepared mesh with high separation efficiency. It is believed that this method should have a promising future in expanding the applications of copper alloys.

Tailoring the structure of metal oxide nanostructures towards enhanced sensing properties for environmental applications.

PubMed

Yang, Mingqing; He, Junhui

2012-02-15

The present article reviews recent works in our laboratory about the sensing properties to toxic gases using nanostructured WO(3), TiO(2), FTiO(2), and CuO functionalized quartz crystal microbalance (QCM) sensors. WO(3) and TiO(2) functionalized QCM sensors have much shorter response time than those functionalized by conventional hydrogen-bond acidic branched copolymers for detection of dimethyl methylphosphonate (DMMP). FTiO(2) functionalized QCM sensors can improve the gas sensing characteristics by shortening the response time but at the price of partial irreversibility. The sensing mechanism was examined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Varied CuO nanostructures were synthesized by simple modulation of reaction conditions. All the as-prepared CuO was applied on QCM resonators and explored for HCN sensing. Surprisingly, responses of all the sensors to HCN were found to be in an opposite direction as compared with other common volatile substances, offering excellent selectivity for HCN detection. The sensitivity was very high, and the response and recovery were very fast. Comparison of the specific surface areas of CuO nanostructures showed that CuO of higher surface area is more sensitive than that of lower surface area, indicating that the specific surface area of these CuO nanostructures plays an important role in the sensitivity of related sensors. Based on experimental results, a sensing mechanism was proposed in which a surface redox reaction occurs between CuO and Cu(2)O on the CuO nanostructures reversibly upon contact with HCN and air, respectively. The CuO functionalized QCM sensors are considered to be a promising candidate for trace HCN gas detection in practical applications. Copyright © 2011 Elsevier Inc. All rights reserved.

Nanostructured superhydrophobic substrates trigger the development of 3D neuronal networks.

PubMed

Limongi, Tania; Cesca, Fabrizia; Gentile, Francesco; Marotta, Roberto; Ruffilli, Roberta; Barberis, Andrea; Dal Maschio, Marco; Petrini, Enrica Maria; Santoriello, Stefania; Benfenati, Fabio; Di Fabrizio, Enzo

2013-02-11

The generation of 3D networks of primary neurons is a big challenge in neuroscience. Here, a novel method is presented for a 3D neuronal culture on superhydrophobic (SH) substrates. How nano-patterned SH devices stimulate neurons to build 3D networks is investigated. Scanning electron microscopy and confocal imaging show that soon after plating neurites adhere to the nanopatterned pillar sidewalls and they are subsequently pulled between pillars in a suspended position. These neurons display an enhanced survival rate compared to standard cultures and develop mature networks with physiological excitability. These findings underline the importance of using nanostructured SH surfaces for directing 3D neuronal growth, as well as for the design of biomaterials for neuronal regeneration. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrathin Carbon Film Protected Silver Nanostructures for Surface-Enhanced Raman Scattering.

PubMed

Peng, Yinshan; Zheng, Xianliang; Tian, Hongwei; Cui, Xiaoqiang; Chen, Hong; Zheng, Weitao

2016-06-23

In this article, ultrathin carbon film protected silver substrate (Ag/C) was prepared via a plasma-enhanced chemical vapor deposition (PECVD) method. The morphological evolution of silver nanostructures underneath, as well as the surface-enhanced Raman scattering (SERS) activity of Ag/C hybrid can be tuned by controlling the deposition time. The stability and reproducibility of the as-prepared hybrid were also studied. © The Author(s) 2016.

Fabrication of Acrylonitrile-Butadiene-Styrene Nanostructures with Anodic Alumina Oxide Templates, Characterization and Biofilm Development Test for Staphylococcus epidermidis

PubMed Central

Desrousseaux, Camille; Cueff, Régis; Aumeran, Claire; Garrait, Ghislain; Mailhot-Jensen, Bénédicte; Traoré, Ousmane; Sautou, Valérie

2015-01-01

Medical devices can be contaminated by microbial biofilm which causes nosocomial infections. One of the strategies for the prevention of such microbial adhesion is to modify the biomaterials by creating micro or nanofeatures on their surface. This study aimed (1) to nanostructure acrylonitrile-butadiene-styrene (ABS), a polymer composing connectors in perfusion devices, using Anodic Alumina Oxide templates, and to control the reproducibility of this process; (2) to characterize the physico-chemical properties of the nanostructured surfaces such as wettability using captive-bubble contact angle measurement technique; (3) to test the impact of nanostructures on Staphylococcus epidermidis biofilm development. Fabrication of Anodic Alumina Oxide molds was realized by double anodization in oxalic acid. This process was reproducible. The obtained molds present hexagonally arranged 50 nm diameter pores, with a 100 nm interpore distance and a length of 100 nm. Acrylonitrile-butadiene-styrene nanostructures were successfully prepared using a polymer solution and two melt wetting methods. For all methods, the nanopicots were obtained but inside each sample their length was different. One method was selected essentially for industrial purposes and for better reproducibility results. The flat ABS surface presents a slightly hydrophilic character, which remains roughly unchanged after nanostructuration, the increasing apparent wettability observed in that case being explained by roughness effects. Also, the nanostructuration of the polymer surface does not induce any significant effect on Staphylococcus epidermidis adhesion. PMID:26284922

Preparation and Photocatalytic Activity of Potassium-Incorporated Titanium Oxide Nanostructures Produced by the Wet Corrosion Process Using Various Titanium Alloys

PubMed Central

Lee, So Yoon; Lee, Choong Hyun; Kim, Do Yun; Locquet, Jean-Pierre; Seo, Jin Won

2015-01-01

Nanostructured potassium-incorporated Ti-based oxides have attracted much attention because the incorporated potassium can influence their structural and physico-chemical properties. With the aim of tuning the structural and physical properties, we have demonstrated the wet corrosion process (WCP) as a simple method for nanostructure fabrication using various Ti-based materials, namely Ti–6Al–4V alloy (TAV), Ti–Ni (TN) alloy and pure Ti, which have 90%, 50% and 100% initial Ti content, respectively. We have systematically investigated the relationship between the Ti content in the initial metal and the precise condition of WCP to control the structural and physical properties of the resulting nanostructures. The WCP treatment involved various concentrations of KOH solutions. The precise conditions for producing K-incorporated nanostructured titanium oxide films (nTOFs) were strongly dependent on the Ti content of the initial metal. Ti and TAV yielded one-dimensional nanowires of K-incorporated nTOFs after treatment with 10 mol/L-KOH solution, whereas TN required a higher concentration (20 mol/L-KOH solution) to produce comparable nanostructures. The obtained nanostructures revealed a blue-shift in UV absorption spectra due to the quantum confinement effects. A significant enhancement of the photocatalytic activity was observed via the chromomeric change and the intermediate formation of methylene blue molecules under UV irradiation. This study demonstrates the WCP as a simple, versatile and scalable method for the production of nanostructured K-incorporated nTOFs to be used as high-performance photocatalysts for environmental and energy applications. PMID:28347071

Self-assembly and hierarchical organization of Ga2O3/In2O3 nanostructures.

PubMed

Xu, Liang; Su, Yong; Li, Sen; Chen, Yiqing; Zhou, Qingtao; Yin, Song; Feng, Yi

2007-02-01

We report on the realization of novel 3-D hierarchical heterostructures with 6-and 4-fold symmetries by a transport and condensation technique. It was found that the major core nanowires or nanobelts are single-crystalline In2O3, and the secondary nanorods are single-crystalline monoclinic beta-Ga2O3 and grow either perpendicular on or slanted to all the facets of the core In2O3 nanobelts. Depending on the diameter of the core In2O3 nanostructures, the secondary Ga2O3 nanorods grow either as a single row or multiple rows. The one-step growth of the unique Ga2O3/In2O3 heteronanostructures is a spontaneous and self-organized process. The simultaneous control of nanocrystal size and shape together with the possibility of growing heterostructures on certain nanocrystal facets opens up novel routes to the synthesis of more sophisticated heterostructures as building blocks for opto- and nanoelectronics.

La 1−x Ca x MnO3 semiconducting nanostructures: morphology and thermoelectric properties

PubMed Central

2014-01-01

Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1−x Ca x MnO3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content. PMID:25206315

RISK REDUCTION VIA GREENER SYNTHESIS OF NOBLE METAL NANOSTRUCTURES AND NANOCOMPOSITES

EPA Science Inventory

Aqueous preparation of nanoparticles using vitamins B2 and C which can function both as reducing and capping agents are described. Bulk and shape-controlled synthesis of noble nanostructures via microwave (MW)-assisted spontaneous reduction of noble metal salts using a-D-glucose,...

Ultrasonic-assisted synthesis of nano lead(II) coordination polymer as precursors for preparation of lead(II) oxide nano-structures: Thermal, optical properties and XRD studies.

PubMed

Ghavidelaghdam, Elham; Shahverdizadeh, Gholam Hossein; Motameni Tabatabai, Javad; Mirtamizdoust, Babak

2018-04-01

Nano structure of a lead (II) coordination polymer [Pb 2 (C 2 Cl 3 O 2 ) 2 (NO 3 ) 2 (C l2 H 8 N 2 ) 2 ] n (1), has been synthesized by a sonochemical method in different concentrations. The nano particles were characterized by scanning electron microscopy (SEM) X-ray powder diffraction (XRD), FT-IR spectroscopy and elemental analyses. The thermal stability of nano structure is closely investigated via thermal gravimetric (TGA), and compared with crystalline structure. The compounds are then heated to 600 °C to produce PbO nano particles. The resulting PbO is characterized through XRD and SEM analyses. Concentration of initial reagents effects on size and morphology of nano-structured compound 1 have been studied and show that low concentrations of initial reagents decreased particles size and leaded to uniform nano particles morphology. The photoluminescence properties of the prepared compound, as crystalline and as nanoparticles, have been investigated. The result showed a good correlation between the size and emission wavelength. Copyright © 2017. Published by Elsevier B.V.

Forging Colloidal Nanostructures via Cation Exchange Reactions

PubMed Central

2016-01-01

Among the various postsynthesis treatments of colloidal nanocrystals that have been developed to date, transformations by cation exchange have recently emerged as an extremely versatile tool that has given access to a wide variety of materials and nanostructures. One notable example in this direction is represented by partial cation exchange, by which preformed nanocrystals can be either transformed to alloy nanocrystals or to various types of nanoheterostructures possessing core/shell, segmented, or striped architectures. In this review, we provide an up to date overview of the complex colloidal nanostructures that could be prepared so far by cation exchange. At the same time, the review gives an account of the fundamental thermodynamic and kinetic parameters governing these types of reactions, as they are currently understood, and outlines the main open issues and possible future developments in the field. PMID:26891471

Forging Colloidal Nanostructures via Cation Exchange Reactions.

PubMed

De Trizio, Luca; Manna, Liberato

2016-09-28

Among the various postsynthesis treatments of colloidal nanocrystals that have been developed to date, transformations by cation exchange have recently emerged as an extremely versatile tool that has given access to a wide variety of materials and nanostructures. One notable example in this direction is represented by partial cation exchange, by which preformed nanocrystals can be either transformed to alloy nanocrystals or to various types of nanoheterostructures possessing core/shell, segmented, or striped architectures. In this review, we provide an up to date overview of the complex colloidal nanostructures that could be prepared so far by cation exchange. At the same time, the review gives an account of the fundamental thermodynamic and kinetic parameters governing these types of reactions, as they are currently understood, and outlines the main open issues and possible future developments in the field.

Mechanically Robust 3D Nanostructure Chitosan-Based Hydrogels with Autonomic Self-Healing Properties.

PubMed

Karimi, Ali Reza; Khodadadi, Azam

2016-10-12

Fabrication of hydrogels based on chitosan (CS) with superb self-healing behavior and high mechanical and electrical properties has become a challenging and fascinating topic. Most of the conventional hydrogels lack these properties at the same time. Our objectives in this research were to synthesize, characterize, and evaluate the general properties of chitosan covalently cross-linked with zinc phthalocyanine tetra-aldehyde (ZnPcTa) framework. Our hope was to access an unprecedented self-healable three-dimensional (3D) nanostructure that would harvest the superior mechanical and electrical properties associated with chitosan. The properties of cross-linker such as the structure, steric effect, and rigidity of the molecule played important roles in determining the microstructure and properties of the resulting hydrogels. The tetra-functionalized phthalocyanines favor a dynamic Schiff-base linkage with chitosan to form a 3D porous nanostructure. Based on this strategy, the self-healing ability, as demonstrated by rheological recovery and macroscopic and microscopic observations, is introduced through dynamic covalent Schiff-base linkage between NH 2 groups in CS and benzaldehyde groups at cross-linker ends. The hydrogel was characterized using FT-IR, NMR, UV/vis, and rheological measurements. In addition, cryogenic scanning electron microscopy (cryo-SEM) was employed as a technique to visualize the internal morphology of the hydrogels. Study of the surface morphology of the hydrogel showed a 3D porous nanostructure with uniform morphology. Furthermore, incorporating the conductive nanofillers, such as carbon nanotubes (CNTs), into the structure can modulate the mechanical and electrical properties of the obtained hydrogels. Interestingly, these hydrogel nanocomposites proved to have very good film-forming properties, high modulus and strength, acceptable electrical conductivity, and excellent self-healing properties at neutral pH. Such properties can be finely tuned

An electrochemical immunosensor for brain natriuretic peptide prepared with screen-printed carbon electrodes nanostructured with gold nanoparticles grafted through aryl diazonium salt chemistry.

PubMed

Serafín, V; Torrente-Rodríguez, R M; González-Cortés, A; García de Frutos, P; Sabaté, M; Campuzano, S; Yáñez-Sedeño, P; Pingarrón, J M

2018-03-01

A sensitive amperometric immunosensor has been prepared by immobilization of capture antibodies onto gold nanoparticles (AuNPs) grafted on a screen-printed carbon electrode (SPCE) through aryl diazonium salt chemistry using 4-aminothiophenol (AuNPs-S-Phe-SPCE). The immunosensor was designed for the accurate determination of clinically relevant levels of B-type natriuretic peptide (BNP) in human serum samples. The nanostructured electrochemical platform resulted in an ordered layer of AuNPs onto SPCEs which combined the advantages of high conductivity and improved stability of immobilized biomolecules. The resulting disposable immunosensor used a sandwich type immunoassay involving a peroxidase-labeled detector antibody. The amperometric transduction was carried out at -0.20V (vs the Ag pseudo-reference electrode) upon the addition of hydroquinone (HQ) as electron transfer mediator and H 2 O 2 as the enzyme substrate. The nanostructured immunosensors show a storage stability of at least 25 days, a linear range between 0.014 and 15ngmL -1 , and a LOD of 4pgmL -1 , which is 100 times lower than the established cut-off value for heart failure (HF) diagnosis. The performance of the immunosensor is advantageously compared with that provided with immunosensors prepared by grafting SPCE with p-phenylendiamine (H 2 N-Phe-SPCE) and attaching AuNPs by immersion into an AuNPs suspension or by electrochemical deposition, as well as with immunosensors constructed using commercial AuNPs-modified SPCEs. The developed immunosensor was applied to the successful analysis of human serum from heart failure (HF) patients upon just a 10-times dilution as sample treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Antireflective nanostructures for CPV

NASA Astrophysics Data System (ADS)

Buencuerpo, Jeronimo; Torne, Lorena; Alvaro, Raquel; Llorens, Jose Manuel; Dotor, María Luisa; Ripalda, Jose Maria

2017-09-01

We have optimized a periodic antireflective nanostructure. The optimal design has a theoretical broadband reflectivity of 0.54% on top of GaInP with an AlInP window layer. Preliminary fabrication attempts have been carried out on top of GaAs substrates. Due to the lack of a window layer, and the need to fine tune the fabrication process, the fabricated nanostructures have a reflectivity of 3.1%, but this is already significantly lower than the theoretical broadband reflectance of standard MgF2/ZnS bilayers (4.5%).

Synthesis of ZnGa2O4 Hierarchical Nanostructure by Au Catalysts Induced Thermal Evaporation

PubMed Central

2010-01-01

In this paper, ZnGa2O4 hierarchical nanostructures with comb-like morphology are fabricated by a simple two-step chemical vapor deposition (CVD) method: first, the Ga2O3 nanowires were synthesized and employed as templates for the growth of ZnGa2O4 nanocombs; then, the as-prepared Ga2O3 nanowires were reacted with ZnO vapor to form ZnGa2O4 nanocombs. Before the reaction, the Au nanoparticles were deposited on the surfaces of Ga2O3 nanowires and used as catalysts to control the teeth growth of ZnGa2O4 nanocombs. The as-prepared ZnGa2O4 nanocombs were highly crystallized with cubic spinel structure. From the photoluminescence (PL) spectrum, a broad band emission in the visible light region was observed of as-prepared ZnGa2O4 nanocombs, which make it promising application as an optical material. PMID:20802787

Self-assembled mirror DNA nanostructures for tumor-specific delivery of anticancer drugs.

PubMed

Kim, Kyoung-Ran; Kim, Hyo Young; Lee, Yong-Deok; Ha, Jong Seong; Kang, Ji Hee; Jeong, Hansaem; Bang, Duhee; Ko, Young Tag; Kim, Sehoon; Lee, Hyukjin; Ahn, Dae-Ro

2016-12-10

Nanoparticle delivery systems have been extensively investigated for targeted delivery of anticancer drugs over the past decades. However, it is still a great challenge to overcome the drawbacks of conventional nanoparticle systems such as liposomes and micelles. Various novel nanomaterials consist of natural polymers are proposed to enhance the therapeutic efficacy of anticancer drugs. Among them, deoxyribonucleic acid (DNA) has received much attention as an emerging material for preparation of self-assembled nanostructures with precise control of size and shape for tailored uses. In this study, self-assembled mirror DNA tetrahedron nanostructures is developed for tumor-specific delivery of anticancer drugs. l-DNA, a mirror form of natural d-DNA, is utilized for resolving a poor serum stability of natural d-DNA. The mirror DNA nanostructures show identical thermodynamic properties to that of natural d-DNA, while possessing far enhanced serum stability. This unique characteristic results in a significant effect on the pharmacokinetics and biodistribution of DNA nanostructures. It is demonstrated that the mirror DNA nanostructures can deliver anticancer drugs selectively to tumors with enhanced cellular and tissue penetration. Furthermore, the mirror DNA nanostructures show greater anticancer effects as compared to that of conventional PEGylated liposomes. Our new approach provides an alternative strategy for tumor-specific delivery of anticancer drugs and highlights the promising potential of the mirror DNA nanostructures as a novel drug delivery platform. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrospinning: A versatile technique for making of 1D growth of nanostructured nanofibers and its applications: An experimental approach

NASA Astrophysics Data System (ADS)

Patil, Jyoti V.; Mali, Sawanta S.; Kamble, Archana S.; Hong, Chang K.; Kim, Jin H.; Patil, Pramod S.

2017-11-01

One dimensional (1D) metal oxide nanostructures (1D-MONS) play a key role in the development of functional devices including energy conversion, energy storage and environmental devices. They are also used for some important biomedical products like wound dressings, filter media, drug delivery and tissue engineering. The electrospinning (ES) is the versatile technique for making of 1D growth of nanostructured nanofibers, an experimental approach and its applications. The present review is focused on the 1D growth of nanostructured nanofibers in different applications like dye sensitized solar cells, perovskite solar cells, fuel cells, lithium ion batteries, redox flow batteries, supercapacitor, photocatalytic, and gas sensors based on ZnO, TiO2, MnO2, WO3, V2O5, NiO, SnO2, Fe2O3 etc. metal oxides, their composites and carbon. This review article presents an introduction to various types of ES techniques and their technical details. Also, the advantages and disadvantages of each ES technique are summarized. The various technical details such as preparative parameters, post-deposition methods, applied electric field, solution feed rate and a distance between a tip to the collector are the key factors in order to obtain exotic 1D nanostructured materials. Also, the lucid literature survey on the growth of nanostructures of various metal oxides and application in different fields are covered in this review. Further, the future perspectives has also been discussed.

Application of Nanostructures in Electrochromic Materials and Devices: Recent Progress

PubMed Central

Wang, Jinmin; Sun, Xiao Wei; Jiao, Zhihui

2010-01-01

The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO3, crystalline WO3 nanoparticles and nanorods, mesoporous WO3 and TiO2, poly(3,4-ethylenedioxythiophene) nanotubes, Prussian blue nanoinks and nanostructures in switchable mirrors are reviewed. The electrochromic properties were significantly enhanced by applying nanostructures, resulting in faster switching responses, higher stability and higher optical contrast. A perspective on the development trends in electrochromic materials and devices is also proposed. PMID:28883368

Fabrication and characterization of nanostructured Mg-doped CdS/AAO nanoporous membrane for sensing applications

NASA Astrophysics Data System (ADS)

Shaban, Mohamed; Mustafa, Mona; Hamdy, Hany

2016-04-01

In this study, Mg-doped CdS nanostructure was deposited onto anodic aluminum oxide (AAO) membrane substrate using sol-gel spin coating method. The AAO membrane was prepared by a two-step anodization process combined with pore widening process. The morphology, chemical composition, and structure of the spin- coated CdS nanostructure have been studied. The morphology of the fabricated AAO membrane and the deposited Mg-doped CdS nanostructure was investigated using scanning electron microscopy (SEM). The SEM of AAO illustrates a typical hexagonal and smooth nanoporous alumina membrane with interpore distance of ~ 100 nm, the pore diameter of ~ 60 nm. SEM of Mgdoped CdS shows porous nanostructured film of CdS nanoparticles. This film well adherents and covers the AAO substrate. The energy dispersive X-ray (EDX) pattern exhibits the signals of Al, O from AAO membrane and Mg, Cd, and S from the deposited CdS. This indicates the high purity of the fabricated membrane and the deposited Mg-doped CdS nanostructure. Using X-ray diffraction (XRD) pattern, Scherrer equation was used to calculate the average crystallite size. Additionally, the texture coefficients and density of dislocations were calculated. The fabricated CdS/AAO was applied to detect glucose of different concentrations. The proposed method has some advantages such as simple technology, low cost of processing, and high throughput. All of these factors facilitate the use of the prepared films in sensing applications.

Formation mechanism of self-assembled polarization-dependent periodic nanostructures in β-Ga2O3

NASA Astrophysics Data System (ADS)

Nakanishi, Y.; Shimotsuma, Y.; Sakakura, M.; Shimizu, M.; Miura, K.

2018-02-01

We have successfully observed self-assembled periodic nanostructures inside Si single crystal and GaP crystal, by the femtosecond double-pulse irradiation. These results experimentally indicate that the self-assembly of the periodic nanostructures inside semiconductors triggered by ultrashort pulses irradiation are possibly associated with a direct or an indirect band gap. More recently we have also empirically classified the photoinduced bulk nanogratings into the following three types: (1) structural deficiency, (2) compressed structure, (3) partial crystallization. We have still a big question about what material properties are involved in the bulk nanograting structure formation. In this study, to expand the selectivity of the material for bulk nanograting formation, we have employed β-Ga2O3 crystals (indirect bandgap Eg 4.8 eV) as a sample for femtosecond laser irradiation. The nanograting structure inside β-Ga2O3 crystal was aligned perpendicular to the laser polarization direction. Such phenomenon is similar to the nanograting in SiO2 glass (Eg 9 eV). Moreover, to clarify the band structure, we have also investigate the photoinduced structure in Sn doped β-Ga2O3 crystals, which exhibit direct bandgap according to the first principle calculation.

Fabrication of solution processed 3D nanostructured CuInGaS₂ thin film solar cells.

PubMed

Chu, Van Ben; Cho, Jin Woo; Park, Se Jin; Hwang, Yun Jeong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

2014-03-28

In this study we demonstrate the fabrication of CuInGaS₂ (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions.

Nano-structured manganese oxide as a cathodic catalyst for enhanced oxygen reduction in a microbial fuel cell fed with a synthetic wastewater.

PubMed

Liu, Xian-Wei; Sun, Xue-Fei; Huang, Yu-Xi; Sheng, Guo-Ping; Zhou, Kang; Zeng, Raymond J; Dong, Fang; Wang, Shu-Guang; Xu, An-Wu; Tong, Zhong-Hua; Yu, Han-Qing

2010-10-01

Microbial fuel cells (MFCs) provide new opportunities for the simultaneous wastewater treatment and electricity generation. Enhanced oxygen reduction capacity of cost-effective metal-based catalysts in an air cathode is essential for the scale-up and commercialization of MFCs in the field of wastewater treatment. We demonstrated that a nano-structured MnO(x) material, prepared by an electrochemically deposition method, could be an effective catalyst for oxygen reduction in an MFC to generate electricity with the maximum power density of 772.8 mW/m(3) and remove organics when the MFC was fed with an acetate-laden synthetic wastewater. The nano-structured MnO(x) with the controllable size and morphology could be readily obtained with the electrochemical deposition method. Both morphology and manganese oxidation state of the nano-scale catalyst were largely dependent on the electrochemical preparation process, and they governed its catalytic activity and the cathodic oxygen reduction performance of the MFC accordingly. Furthermore, cyclic voltammetry (CV) performed on each nano-structured material suggests that the MnO(x) nanorods had an electrochemical activity towards oxygen reduction reaction via a four-electron pathway in a neutral pH solution. This work provides useful information on the facile preparation of cost-effective cathodic catalysts in a controllable way for the single-chamber air-cathode MFC for wastewater treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Nanostructured layers of thermoelectric materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Urban, Jeffrey J.; Lynch, Jared; Coates, Nelson

This disclosure provides systems, methods, and apparatus related to thermoelectric materials. In one aspect, a method includes providing a plurality of nanostructures. The plurality of nanostructures comprise a thermoelectric material, with each nanostructure of the plurality of nanostructures having first ligands disposed on a surface of the nanostructure. The plurality of nanostructures is mixed with a solution containing second ligands and a ligand exchange process occurs in which the first ligands disposed on the plurality of nanostructures are replaced with the second ligands. The plurality of nanostructures is deposited on a substrate to form a layer. The layer is thermallymore » annealed.« less

Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

PubMed Central

Vukovic, Ivana; Punzhin, Sergey; Voet, Vincent S. D.; Vukovic, Zorica; de Hosson, Jeff Th. M.; ten Brinke, Gerrit; Loos, Katja

2014-01-01

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, have high porosity, high surface-to-volume and strength-to-weight ratio. Unfortunately, common approaches for preparation of metallic nanostructures render materials with highly disordered architecture, which might have an adverse effect on their mechanical properties. Block copolymers have the ability to self-assemble into ordered nanostructures and can be applied as templates for the preparation of well-ordered metal nanofoams. Here we describe the application of a block copolymer-based supramolecular complex - polystyrene-block-poly(4-vinylpyridine)(pentadecylphenol) PS-b-P4VP(PDP) - as a precursor for well-ordered nickel nanofoam. The supramolecular complexes exhibit a phase behavior similar to conventional block copolymers and can self-assemble into the bicontinuous gyroid morphology with two PS networks placed in a P4VP(PDP) matrix. PDP can be dissolved in ethanol leading to the formation of a porous structure that can be backfilled with metal. Using electroless plating technique, nickel can be inserted into the template's channels. Finally, the remaining polymer can be removed via pyrolysis from the polymer/inorganic nanohybrid resulting in nanoporous nickel foam with inverse gyroid morphology. PMID:24797367

Gyroid nickel nanostructures from diblock copolymer supramolecules.

PubMed

Vukovic, Ivana; Punzhin, Sergey; Voet, Vincent S D; Vukovic, Zorica; de Hosson, Jeff Th M; ten Brinke, Gerrit; Loos, Katja

2014-04-28

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, have high porosity, high surface-to-volume and strength-to-weight ratio. Unfortunately, common approaches for preparation of metallic nanostructures render materials with highly disordered architecture, which might have an adverse effect on their mechanical properties. Block copolymers have the ability to self-assemble into ordered nanostructures and can be applied as templates for the preparation of well-ordered metal nanofoams. Here we describe the application of a block copolymer-based supramolecular complex - polystyrene-block-poly(4-vinylpyridine)(pentadecylphenol) PS-b-P4VP(PDP) - as a precursor for well-ordered nickel nanofoam. The supramolecular complexes exhibit a phase behavior similar to conventional block copolymers and can self-assemble into the bicontinuous gyroid morphology with two PS networks placed in a P4VP(PDP) matrix. PDP can be dissolved in ethanol leading to the formation of a porous structure that can be backfilled with metal. Using electroless plating technique, nickel can be inserted into the template's channels. Finally, the remaining polymer can be removed via pyrolysis from the polymer/inorganic nanohybrid resulting in nanoporous nickel foam with inverse gyroid morphology.

Synthesis of nano-structured tin oxide thin films with faster response to LPG and ammonia by spray pyrolysis

NASA Astrophysics Data System (ADS)

PrasannaKumari, K.; Thomas, Boben

2018-01-01

Nanostructured SnO2 thin film have been efficiently fabricated by spray pyrolysis using atomizers of different types. The structure and morphology of as-prepared samples are investigated by techniques such as x-ray diffraction, and field-emission scanning electron microscopy. Significant morphological changes are observed in films by modifying the precursor atomization as a result of change of spray device. The optical characterization indicates that change in atomization, affects the absorbance and the band gap, following the varied crystallite size. Gas sensing investigations on ultrasonically prepared tin oxide films show NH3 response at operating temperatures lower down to 50 °C. For 1000 ppm of LPG the response at 350 °C for air blast atomizer film is about 99%, with short response and recovery times. The photoluminescence emmision spectra reveal the correlation between atomization process and the quantity of oxygen vacancies present in the samples. The favorable size reduction in microstructure with good crystallinity with slight change in lattice properties suggest their scope in gas sensing applications. On the basis of these characterizations, the mechanism of LPG and NH3 gas sensing of nanostructured SnO2 thin films has been proposed.

Recent developments in the fabrication of ordered nanostructure arrays based on nanosphere lithography.

PubMed

Wei, Xueyong

2010-11-01

Since it was invented two decades ago, Nanosphere Lithography (NSL) has been widely studied as a low cost and flexible technique to fabricate nanostructures. Based on the registered patents and some selected papers, this review will discuss recent developments of different NSL strategies for the fabrication of ordered nanostructure arrays. The mechanism of self-assembly process and the techniques for preparing the self-assembled nanosphere template are first briefly introduced. The nanosphere templates are used either as shadow masks or as moulds for pattern transfer. Much more work now combines NSL with other lithographic techniques and material growth methods to form novel nanostructures of complex shape or various materials. Hence, this review finally gives a discussion on some future directions in NSL study.

Optical and magnetic properties of Co-doped CuO flower/plates/particles-like nanostructures.

PubMed

Basith, N Mohamed; Vijaya, J Judith; Kennedy, L John; Bououdina, M; Hussain, Shamima

2014-03-01

In this study, pure and Co-doped CuO nanostructures (0.5, 1.0, 1.5, and 2.0 at wt% of Co) were synthesized by microwave combustion method. The prepared samples were characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). Powder X-ray diffraction patterns refined by the Rietveld method indicated the formation of single-phase monoclinic structure. The surface morphology and elemental analysis of Co-doped CuO nanostructures were studied by using HR-SEM and EDX. Interestingly, the morphology was found to change considerably from nanoflowers to nanoplates then to nanoparticles with the variation of Co concentration. The optical band gap calculated using DRS was found to be 2.1 eV for pure CuO and increases up to 3.4 eV with increasing cobalt content. Photoluminescence measurements also confirm these results. The magnetic measurements indicated that the obtained nanostructures were ferromagnetic at room temperature with an optimum value of saturation magnetization at 1.0 wt.% of Co-doped CuO, i.e., 970 micro emu/g.

Physicochemical and Electrophysical Properties of Metal/Semiconductor Containing Nanostructured Composites

NASA Astrophysics Data System (ADS)

Gerasimov, G. N.; Gromov, V. F.; Trakhtenberg, L. I.

2018-06-01

The properties of nanostructured composites based on metal oxides and metal-polymer materials are analyzed, along with ways of preparing them. The effect the interaction between metal and semiconductor nanoparticles has on the conductivity, photoconductivity, catalytic activity, and magnetic, dielectric, and sensor properties of nanocomposites is discussed. It is shown that as a result of this interaction, a material can acquire properties that do not exist in systems of isolated particles. The transfer of electrons between metal particles of different sizes in polymeric matrices leads to specific dielectric losses, and to an increase in the rate and a change in the direction of chemical reactions catalyzed by these particles. The interaction between metal-oxide semiconductor particles results in the electronic and chemical sensitization of sensor effects in nanostructured composite materials. Studies on creating molecular machines (Brownian motors), devices for magnetic recording of information, and high-temperature superconductors based on nanostructured systems are reviewed.

Pulsed photonic fabrication of nanostructured metal oxide thin films

NASA Astrophysics Data System (ADS)

Bourgeois, Briley B.; Luo, Sijun; Riggs, Brian C.; Adireddy, Shiva; Chrisey, Douglas B.

2017-09-01

Nanostructured metal oxide thin films with a large specific surface area are preferable for practical device applications in energy conversion and storage. Herein, we report instantaneous (milliseconds) photonic synthesis of three-dimensional (3-D) nanostructured metal oxide thin films through the pulsed photoinitiated pyrolysis of organometallic precursor films made by chemical solution deposition. High wall-plug efficiency-pulsed photonic irradiation (xenon flash lamp, pulse width of 1.93 ms, fluence of 7.7 J/cm2 and frequency of 1.2 Hz) is used for scalable photonic processing. The photothermal effect of subsequent pulses rapidly improves the crystalline quality of nanocrystalline metal oxide thin films in minutes. The following paper highlights pulsed photonic fabrication of 3-D nanostructured TiO2, Co3O4, and Fe2O3 thin films, exemplifying a promising new method for the low-cost and high-throughput manufacturing of nanostructured metal oxide thin films for energy applications.

LPG ammonia and nitrogen dioxide gas sensing properties of nanostructured polypyrrole thin film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagul, Sagar B., E-mail: nano.sbbagul@gmail.com; Upadhye, Deepak S.; Sharma, Ramphal, E-mail: rps.phy@gmail.com

Nanostructured Polypyrrole thin film was synthesized by easy and economic chemical oxidative polymerization technique on glass at room temperature. The prepared thin film of Polypyrrole was characterized by optical absorbance study by UV-visible spectroscopy and electrical study by I-V measurement system. The optical absorbance spectrum of Polypyrrole shows two fundamental peaks in region of 420 and 890 nm, which confirms the formation of Polypyrrole on glass substrate. The I-V graph of nanostructured Polypyrrole represents the Ohmic nature. Furthermore, the thin film of Polypyrrole was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents spherical nanostructured morphology ofmore » Polypyrrole on glass substrate. In order to investigate gas sensing properties, 100 ppm of LPG, Ammonia and Nitrogen Dioxide were injected in the gas chamber and magnitude of resistance has been recorded as a function of time in second. It was observed that nanostructured Polypyrrole thin film shows good sensing behavior at room temperature.« less

LPG ammonia and nitrogen dioxide gas sensing properties of nanostructured polypyrrole thin film

NASA Astrophysics Data System (ADS)

Bagul, Sagar B.; Upadhye, Deepak S.; Sharma, Ramphal

2016-05-01

Nanostructured Polypyrrole thin film was synthesized by easy and economic chemical oxidative polymerization technique on glass at room temperature. The prepared thin film of Polypyrrole was characterized by optical absorbance study by UV-visible spectroscopy and electrical study by I-V measurement system. The optical absorbance spectrum of Polypyrrole shows two fundamental peaks in region of 420 and 890 nm, which confirms the formation of Polypyrrole on glass substrate. The I-V graph of nanostructured Polypyrrole represents the Ohmic nature. Furthermore, the thin film of Polypyrrole was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents spherical nanostructured morphology of Polypyrrole on glass substrate. In order to investigate gas sensing properties, 100 ppm of LPG, Ammonia and Nitrogen Dioxide were injected in the gas chamber and magnitude of resistance has been recorded as a function of time in second. It was observed that nanostructured Polypyrrole thin film shows good sensing behavior at room temperature.

Oil-Impregnated Oxide Nanostructures for Aluminum Corrosion Prevention

DTIC Science & Technology

2017-12-18

and self- healing capability. Figure 1 illustrates the key idea proposed in this research , i.e., employing oil instead of air for the interfacial...the preparation of polyaniline nanostructures and their applications in anticorrosive coatings. RSC Advances 2014, 4 (54), 28195-28208. 23. Solomon ...2), 263-269. 38. Maroo, S. C.; Chung, J., Negative pressure characteristics of an evaporating meniscus at nanoscale. Nanoscale Research Letters

In-vitro antibacterial study of zinc oxide nanostructures on Streptococcus sobrinus

NASA Astrophysics Data System (ADS)

Bakhori, Siti Khadijah Mohd; Mahmud, Shahrom; Ann, Ling Chuo; Sirelkhatim, Amna; Hasan, Habsah; Mohamad, Dasmawati; Masudi, Sam'an Malik; Seeni, Azman; Rahman, Rosliza Abd

2014-10-01

Zinc oxide nanostructures were prepared using a pilot plant of zinc oxide boiling furnace. Generally, it produced two types of nanostructures different in morphology; one is rod-like shaped (ZnO-1) and a plate-like shape (ZnO-2). The properties of ZnO were studied by structural, optical and morphological using XRD, PL and FESEM respectively. The XRD patterns confirmed the wurtzite structures of ZnO with the calculated crystallite size of 41 nm (ZnO-1) and 42 nm (ZnO-2) using Scherrer formula. The NBE peaks were determined by photoluminescence spectra which reveal peak at 3.25 eV and 3.23 eV for ZnO-1 and ZnO-2 respectively. Prior to that, the morphologies for both ZnO-1 and ZnO-2 were demonstrated from FESEM micrographs. Subsequently the antibacterial study was conducted using in-vitro broth dilution technique towards a gram positive bacterium Streptococcus sobrinus (ATCC 33478) to investigate the level of antibacterial effect of zinc oxide nanostructures as antibacterial agent. Gradual increment of ZnO concentrations from 10-20 mM affected the inhibition level after twenty four hours of incubation. In conjunction with concentration increment of ZnO, the percentage inhibition towards Streptococcus sobrinus was also increased accordingly. The highest inhibition occurred at 20 mM of ZnO-1 and ZnO-2 for 98% and 77% respectively. It showed that ZnO has good properties as antibacterial agent and relevancy with data presented by XRD, PL and FESEM were determined.

Growth of nanostructures with controlled diameter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pfefferle, Lisa; Haller, Gary; Ciuparu, Dragos

2009-02-03

Transition metal-substituted MCM-41 framework structures with a high degree of structural order and a narrow pore diameter distribution were reproducibly synthesized by a hydrothermal method using a surfactant and an anti-foaming agent. The pore size and the mesoporous volume depend linearly on the surfactant chain length. The transition metals, such as cobalt, are incorporated substitutionally and highly dispersed in the silica framework. Single wall carbon nanotubes with a narrow diameter distribution that correlates with the pore diameter of the catalytic framework structure were prepared by a Boudouard reaction. Nanostructures with a specified diameter or cross-sectional area can therefore be predictablymore » prepared by selecting a suitable pore size of the framework structure.« less

A Comprehensive Review of One-Dimensional Metal-Oxide Nanostructure Photodetectors

PubMed Central

Zhai, Tianyou; Fang, Xiaosheng; Liao, Meiyong; Xu, Xijin; Zeng, Haibo; Yoshio, Bando; Golberg, Dmitri

2009-01-01

One-dimensional (1D) metal-oxide nanostructures are ideal systems for exploring a large number of novel phenomena at the nanoscale and investigating size and dimensionality dependence of nanostructure properties for potential applications. The construction and integration of photodetectors or optical switches based on such nanostructures with tailored geometries have rapidly advanced in recent years. Active 1D nanostructure photodetector elements can be configured either as resistors whose conductions are altered by a charge-transfer process or as field-effect transistors (FET) whose properties can be controlled by applying appropriate potentials onto the gates. Functionalizing the structure surfaces offers another avenue for expanding the sensor capabilities. This article provides a comprehensive review on the state-of-the-art research activities in the photodetector field. It mainly focuses on the metal oxide 1D nanostructures such as ZnO, SnO2, Cu2O, Ga2O3, Fe2O3, In2O3, CdO, CeO2, and their photoresponses. The review begins with a survey of quasi 1D metal-oxide semiconductor nanostructures and the photodetector principle, then shows the recent progresses on several kinds of important metal-oxide nanostructures and their photoresponses and briefly presents some additional prospective metal-oxide 1D nanomaterials. Finally, the review is concluded with some perspectives and outlook on the future developments in this area. PMID:22454597

Formation of Different Si3N4 Nanostructures by Salt-Assisted Nitridation.

PubMed

Liu, Xiongzhang; Guo, Ran; Zhang, Sengjing; Li, Qingda; Saito, Genki; Yi, Xuemei; Nomura, Takahiro

2018-04-11

Silicon nitride (Si 3 N 4 ) products with different nanostructure morphologies and different phases for Si 3 N 4 ceramic with high thermal conductivity were synthesized by a direct nitriding method. NaCl and NH 4 Cl were added to raw Si powders, and the reaction was carried out under a nitrogen gas flow of 100 mL/min. The phase composition and morphologies of the products were systemically characterized by X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. At 1450 °C, the NaCl content was 30 wt %, the NH 4 Cl content was 3 wt %, and the maximum α-Si 3 N 4 content was 96 wt %. The process of Si nitridation can be divided into three stages by analyzing the reaction schemes: in the first stage (25-900 °C), NH 4 Cl decomposition and the generation of stacked amorphous Si 3 N 4 occurs; in the second stage (900-1450 °C), NaCl melts and Si 3 N 4 generates; and in the third stage (>1450 °C), α-Si 3 N 4 → β-Si 3 N 4 phase change and the evaporation of NaCl occurs. The products are made of two layers: a thin upper layer of nanowires containing different nanostructures and a lower layer mainly comprising fluffy, blocky, and short needlelike products. The introduction of NaCl and NH 4 Cl facilitated the evaporation of Si powders and the decomposition of Al 2 O 3 from porcelain boat and furnace tube, which resulted in the mixing of N 2 , O 2 , Al 2 O, and Si vapors and generated Al x Si y O z nanowires with rough surfaces and lead to thin Si 3 N 4 nanowires, nanobranches by the vapor-solid (VS), vapor-liquid-solid (VLS), and the double-stage VLS base and VS tip growth mechanisms.

On-site chemical pre-lithiation of S cathode at room temperature on a 3D nano-structured current collector

NASA Astrophysics Data System (ADS)

Wu, Yunwen; Momma, Toshiyuki; Ahn, Seongki; Yokoshima, Tokihiko; Nara, Hiroki; Osaka, Tetsuya

2017-10-01

This work reports a new chemical pre-lithiation method to fabricate lithium sulfide (Li2S) cathode. This pre-lithiation process is taken place simply by dropping the organolithium reagent lithium naphthalenide (Li+Naph-) on the prepared sulfur cathode. It is the first time realizing the room temperature chemical pre-lithaition reaction attributed by the 3D nanostructured carbon nanotube (CNT) current collector. It is confirmed that the Li2S cathode fabricated at room temperature showing higher capacity and lower hysteresis than the Li2S cathode fabricated at high temperature pre-lithiation. The pre-lithiated Li2S cathode at room temperature shows stable cycling performance with a 600 mAh g-1 capacity after 100 cycles at 0.1 C-rate and high capacity of 500 mAh g-1 at 2 C-rate. This simple on-site pre-lithiation method at room temperature is demonstrated to be applicable for the in-situ pre-lithiation in a Li metal free battery.

Nanostructured composite reinforced material

DOEpatents

Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

2012-07-31

A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

The design, fabrication, and photocatalytic utility of nanostructured semiconductors: focus on TiO2-based nanostructures

PubMed Central

Banerjee, Arghya Narayan

2011-01-01

Recent advances in basic fabrication techniques of TiO2-based nanomaterials such as nanoparticles, nanowires, nanoplatelets, and both physical- and solution-based techniques have been adopted by various research groups around the world. Our research focus has been mainly on various deposition parameters used for fabricating nanostructured materials, including TiO2-organic/inorganic nanocomposite materials. Technically, TiO2 shows relatively high reactivity under ultraviolet light, the energy of which exceeds the band gap of TiO2. The development of photocatalysts exhibiting high reactivity under visible light allows the main part of the solar spectrum to be used. Visible light-activated TiO2 could be prepared by doping or sensitizing. As far as doping of TiO2 is concerned, in obtaining tailored material with improved properties, metal and nonmetal doping has been performed in the context of improved photoactivity. Nonmetal doping seems to be more promising than metal doping. TiO2 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. Additionally, it can be used as an antibacterial agent because of its strong oxidation activity and superhydrophilicity. Therefore, applications of TiO2 in terms of photocatalytic activities are discussed here. The basic mechanisms of the photoactivities of TiO2 and nanostructures are considered alongside band structure engineering and surface modification in nanostructured TiO2 in the context of doping. The article reviews the basic structural, optical, and electrical properties of TiO2, followed by detailed fabrication techniques of 0-, 1-, and quasi-2-dimensional TiO2 nanomaterials. Applications and future directions of nanostructured TiO2 are considered in the context of various photoinduced phenomena such as hydrogen production, electricity generation via dye-sensitized solar cells, photokilling and self-cleaning effect, photo-oxidation of organic pollutant, wastewater management, and

Impedimetric detection of alcohol vapours using nanostructured zinc ferrite.

PubMed

Kannan, Padmanathan Karthick; Saraswathi, Ramiah

2014-11-01

A comparative study on the sensing characteristics of nanostructured zinc ferrite to three primary alcohols viz. methanol, ethanol and propanol has been carried out. The zinc ferrite has been prepared by a combustion method and characterized by XRD, FTIR, AFM and SEM. Impedance studies in the alcohol concentration range varying from 100 to 1000 ppm show definite variations in response to both the nature of the alcohol and its concentration. The nanostructured zinc ferrite shows the highest sensor response to methanol and least to propanol. Equivalent circuit modelling and calibration have been made for all the three alcohol sensors. The material shows a better selectivity to the alcohols compared to formaldehyde, ammonia and acetone vapours. Copyright © 2014 Elsevier B.V. All rights reserved.

Studies of surface morphology and optical properties of ZnO nanostructures grown on different molarities of TiO{sub 2} seed layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asib, N. A. M., E-mail: amierahasib@yahoo.com; Afaah, A. N.; Aadila, A.

Titanium dioxide (TiO{sub 2}) seed layer was prepared by using sol-gel spin-coating technique, followed by growth of 0.01 M of Zinc oxide (ZnO) nanostructures by solution-immersion. The molarities of TiO{sub 2} seed layer were varied from 1.1 M to 0.100 M on glass substrates. The nanostructures thin films were characterized by Field Emission Scanning Electrons Microscope (FESEM), Photoluminescence (PL) spectroscopy and Ultraviolet-Visible (UV-Vis) spectroscopy. FESEM images demonstrate that needle-like ZnO nanostructures are formed on all TiO{sub 2} seed layer. The smallest diameter of needle-like ZnO nanostructures (90.3 nm) were deposited on TiO{sub 2} seed layer of 0.100 M. PL spectramore » of the TiO{sub 2}: ZnO nanostructures thin films show the blue shifted emissions in the UV regions compared to the ZnO thin film. Meanwhile, UV-vis spectra of films display high absorption in the UV region and high trasparency in the visible region. The highest absorbance at UV region was recorded for sample which has 0.100 M of TiO{sub 2} seed layer.« less

Facile preparation of dendritic Ag-Pd bimetallic nanostructures on the surface of Cu foil for application as a SERS-substrate

NASA Astrophysics Data System (ADS)

Yi, Zao; Tan, Xiulan; Niu, Gao; Xu, Xibin; Li, Xibo; Ye, Xin; Luo, Jiangshan; Luo, Binchi; Wu, Weidong; Tang, Yongjian; Yi, Yougen

2012-05-01

Dendritic Ag-Pd bimetallic nanostructures have been synthesized on the surface of Cu foil via a multi-stage galvanic replacement reaction (MGRR) of Ag dendrites in a Na2PdCl4 solution. After five stages of replacement reaction, one obtained structures with protruding Ag-Pd flakes; these will mature into many porous structures with a few Ag atoms that are left over dendrites. The dendritic Ag-Pd bimetallic nanostructures were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), selected area electron diffraction (SAED) and X-ray photoelectron spectroscopy (XPS). The morphology of the products strongly depended on the stage of galvanic replacement reaction and reaction temperature. The morphology and composition-dependent surface-enhanced Raman scattering (SERS) of the as-synthesized Ag-Pd bimetallic nanostructures were investigated. The effectiveness of these dendritic Ag-Pd bimetallic nanostructures on the surface of Cu foil as substrates toward SERS detection was evaluated by using rhodamine 6G (R6G) as a probe molecule. The results indicate that as-synthesized dendritic Ag-Pd bimetallic nanostructures are good candidates for SERS spectroscopy.

Self-Assembled Hierarchical Formation of Conjugated 3D Cobalt Oxide Nanobead-CNT-Graphene Nanostructure Using Microwaves for High-Performance Supercapacitor Electrode.

PubMed

Kumar, Rajesh; Singh, Rajesh Kumar; Dubey, Pawan Kumar; Singh, Dinesh Pratap; Yadav, Ram Manohar

2015-07-15

Here we report the electrochemical performance of a interesting three-dimensional (3D) structures comprised of zero-dimensional (0D) cobalt oxide nanobeads, one-dimensional (1D) carbon nanotubes and two-dimensional (2D) graphene, stacked hierarchically. We have synthesized 3D self-assembled hierarchical nanostructure comprised of cobalt oxide nanobeads (Co-nb), carbon nanotubes (CNTs), and graphene nanosheets (GNSs) for high-performance supercapacitor electrode application. This 3D self-assembled hierarchical nanostructure Co3O4 nanobeads-CNTs-GNSs (3D:Co-nb@CG) is grown at a large scale (gram) through simple, facile, and ultrafast microwave irradiation (MWI). In 3D:Co-nb@CG nanostructure, Co3O4 nanobeads are attached to the CNT surfaces grown on GNSs. Our ultrafast, one-step approach not only renders simultaneous growth of cobalt oxide and CNTs on graphene nanosheets but also institutes the intrinsic dispersion of carbon nanotubes and cobalt oxide within a highly conductive scaffold. The 3D:Co-nb@CG electrode shows better electrochemical performance with a maximum specific capacitance of 600 F/g at the charge/discharge current density of 0.7A/g in KOH electrolyte, which is 1.56 times higher than that of Co3O4-decorated graphene (Co-np@G) nanostructure. This electrode also shows a long cyclic life, excellent rate capability, and high specific capacitance. It also shows high stability after few cycles (550 cycles) and exhibits high capacitance retention behavior. It was observed that the supercapacitor retained 94.5% of its initial capacitance even after 5000 cycles, indicating its excellent cyclic stability. The synergistic effect of the 3D:Co-nb@CG appears to contribute to the enhanced electrochemical performances.

Enhanced photoluminescence intensity by modifying the surface nanostructure of Nd3+-doped (Pb, La)(Zr, Ti)O3 ceramics.

PubMed

Xu, Long; Zhang, Jingwen; Zhao, Hua; Sun, Haibin; Xu, Caixia

2017-09-01

Quasi-period cylindrical nanostructures with both diameters and intervals of about 100 nm are manufactured on the surfaces of Nd 3+ -doped lanthanum lead zirconate titanate ceramics by femtosecond laser irradiation under SF 6 atmosphere. A light-emission enhancement of more than 20 times is investigated, accompanied by an extremely long trailing-off time of light emission and lower threshold. A specific polarization state of the light emission is achieved and tuned by changing the incident regions of the pumping source. The increased absorption coefficient of the specimen is discussed based on multiple scattering and weak localization of light. In addition, both the scatterers provided by the laser-machined nanostructure and the recurrent photoinduced trapping and re-excitation process participated in the enhancement of the light emission. This Letter offers new insight to improve the luminescence property of laser materials, as well as to broaden the range of exploring the weak localization of light and random lasers.

Liquid exfoliation of mechanochemically nanostructured tungsten disulfide to a graphene-like state

NASA Astrophysics Data System (ADS)

Posudievsky, Oleg Yu; Khazieieva, Oleksandra A.; Kondratyuk, Andrii S.; Cherepanov, Vsevolod V.; Dovbeshko, Galina I.; Koshechko, Vyacheslav G.; Pokhodenko, Vitaly D.

2018-02-01

The possibility of the efficient preparation of graphene-like 1H-WS2 by the primary solventless nanostructuration of bulk 2H-WS2 by means of its mechanochemical treatment in the presence of a chemically inert agent (NaCl) and the subsequent liquid exfoliation of the nanostructured 2H-WS2 in an organic solvent is shown for the first time. The shear stresses generated during the grinding of the WS2/NaCl mixture caused the formation of WS2 particles with a reduced number of layers, while the stresses normal to their surface led to their cracking and a significant reduction in lateral size. The graphene-like morphology of the 1H-WS2 nanoparticles in the prepared dispersions is confirmed by atomic force microscopy and Raman spectroscopy. The semiconducting character of 1Н-WS2 is supported by electron absorption and x-ray photoelectron spectroscopy data.

An inorganic capping strategy for the seeded growth of versatile bimetallic nanostructures

DOE PAGES

Pei, Yuchen; Maligal-Ganesh, Raghu V.; Xiao, Chaoxian; ...

2015-09-11

Metal nanostructures have attracted great attention in various fields due to their tunable properties through precisely tailored sizes, compositions and structures. Using mesoporous silica (mSiO 2) as the inorganic capping agent and encapsulated Pt nanoparticles as the seeds, we developed a robust seeded growth method to prepare uniform bimetallic nanoparticles encapsulated in mesoporous silica shells (PtM@mSiO 2, M = Pd, Rh, Ni and Cu). Unexpectedly, we found that the inorganic silica shell is able to accommodate an eight-fold volume increase in the metallic core by reducing its thickness. The bimetallic nanoparticles encapsulated in mesoporous silica shells showed enhanced catalytic propertiesmore » and thermal stabilities compared with those prepared with organic capping agents. As a result, this inorganic capping strategy could find a broad application in the synthesis of versatile bimetallic nanostructures with exceptional structural control and enhanced catalytic properties.« less

Photoelectrochemical Water Splitting Properties of Ti-Ni-Si-O Nanostructures on Ti-Ni-Si Alloy.

PubMed

Li, Ting; Ding, Dongyan; Dong, Zhenbiao; Ning, Congqin

2017-10-31

Ti-Ni-Si-O nanostructures were successfully prepared on Ti-1Ni-5Si alloy foils via electrochemical anodization in ethylene glycol/glycerol solutions containing a small amount of water. The Ti-Ni-Si-O nanostructures were characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and diffuse reflectance absorption spectra. Furthermore, the photoelectrochemical water splitting properties of the Ti-Ni-Si-O nanostructure films were investigated. It was found that, after anodization, three different kinds of Ti-Ni-Si-O nanostructures formed in the α-Ti phase region, Ti₂Ni phase region, and Ti₅Si₃ phase region of the alloy surface. Both the anatase and rutile phases of Ti-Ni-Si-O oxide appeared after annealing at 500 °C for 2 h. The photocurrent density obtained from the Ti-Ni-Si-O nanostructure photoanodes was 0.45 mA/cm² at 0 V (vs. Ag/AgCl) in 1 M KOH solution. The above findings make it feasible to further explore excellent photoelectrochemical properties of the nanostructure-modified surface of Ti-Ni-Si ternary alloys.

3D Nanostructured materials: TiO2 nanoparticles incorporated gellan gum scaffold for photocatalyst and biomedical Applications

NASA Astrophysics Data System (ADS)

Hasmizam Razali, Mohd; Arifah Ismail, Nur; Zulkafli, Mohd Farhan Azly Mohd; Anuar Mat Amin, Khairul

2018-03-01

A unique three-dimensional (3D) nanostructured gellan gum (GG) is fabricated by incorporating TiO2 nanoparticles (GG + TiO2NPs) scaffold by freeze-drying. The fabricated GG + TiO2NPs were characterized using Fourier transform infrared (FTIR), x-ray diffraction (XRD), and scanning electron microscopy (SEM) to study their physiochemical properties. FTIR was used to investigate the intermolecular interactions in the scaffolds. The crystal structure was determined by bulk analysis using XRD and SEM for microstructure observation of scaffold surfaces. The performance of synthesized GG + TiO2NPs scaffold 3D nanostructured materials was evaluated as a photocatalyst for methyl orange (MO) degradation and for biomedical applications. The results showed that the scaffold possessed good photocatalytic activity for removal of methyl orange with 88.24% degradation after 3 h of UV irradiation. The scaffold also induces the cell growth, thus offering a good candidate for biomedical applications.

Synthesis, Structural and Morphological Property of BaSnO3 Nanopowder Prepared by Solid State Ceramic Method

NASA Astrophysics Data System (ADS)

John, Jibi; Mahadevan Pillai, V. P.; Thomas, Anitta Rose; Philip, Reji; Joseph, Jaison; Muthunatesan, S.; Ragavendran, V.; Prabhu, Radhakrishna

2017-05-01

BaSnO3 is a cubic perovskite-type oxide that behaves as an n-type semiconductor with a wide band gap of 3.4 eV and remains stable at temperatures up to 1000°C. It has wide applications such as thermally stable capacitors, humidity sensors, gas sensors, etc. Barium stannate has also been used in optical applications, in capacitors and ceramic boundary layers, and as a promising material to produce gas phase sensors for the detection of carbon monoxide and carbon dioxide. BaSnO3 powder was prepared by solid state ceramic method. X-ray diffraction pattern of the prepared sample presents all the characteristic peaks of cubic phase of BaSnO3 (JCPDScard no: 15 -0780). The lattice constant for the compound was calculated and found to be 4.101A0 which is in agreement with the reported value (4.112A0). The average size of the crystallites estimated by Debye Scherrer’s formula was found to be 49 nm shows the nanostructured nature. The Raman bands observed ~ 139, 833 and 1122 cm-1 can be assigned on the basis of the fundamental vibrations of SnO6 octahedron which has Oh symmetry, in the distorted perovskite structure. The SEM image shows a porous surface morphology with grains of cuboidal structure with well-defined grain boundaries. UV-Visible spectra shows BaSnO3powder exhibit high reflectance in the 400-700 nm range.

Reconfigurable Three-Dimensional Gold Nanorod Plasmonic Nanostructures Organized on DNA Origami Tripod.

PubMed

Zhan, Pengfei; Dutta, Palash K; Wang, Pengfei; Song, Gang; Dai, Mingjie; Zhao, Shu-Xia; Wang, Zhen-Gang; Yin, Peng; Zhang, Wei; Ding, Baoquan; Ke, Yonggang

2017-02-28

Distinct electromagnetic properties can emerge from the three-dimensional (3D) configuration of a plasmonic nanostructure. Furthermore, the reconfiguration of a dynamic plasmonic nanostructure, driven by physical or chemical stimuli, may generate a tailored plasmonic response. In this work, we constructed a 3D reconfigurable plasmonic nanostructure with controllable, reversible conformational transformation using bottom-up DNA self-assembly. Three gold nanorods (AuNRs) were positioned onto a reconfigurable DNA origami tripod. The internanorod angle and distance were precisely tuned through operating the origami tripod by toehold-mediated strand displacement. The transduction of conformational change manifested into a controlled shift of the plasmonic resonance peak, which was studied by dark-field microscopy, and agrees well with electrodynamic calculations. This new 3D plasmonic nanostructure not only provides a method to study the plasmonic resonance of AuNRs at prescribed 3D conformations but also demonstrates that DNA origami can serve as a general self-assembly platform for constructing various 3D reconfigurable plasmonic nanostructures with customized optical properties.

A comparative study on omnidirectional anti-reflection SiO2 nanostructure films coating by glancing angle deposition

NASA Astrophysics Data System (ADS)

Prachachet, R.; Samransuksamer, B.; Horprathum, M.; Eiamchai, P.; Limwichean, S.; Chananonnawathorn, C.; Lertvanithphol, T.; Muthitamongkol, P.; Boonruang, S.; Buranasiri, P.

2018-02-01

Fabricated omnidirectional anti-reflection nanostructure films as a one of the promising alternative solar cell applications have attracted enormous scientific and industrial research benefits to their broadband, effective over a wide range of incident angles, lithography-free and high-throughput process. Recently, the nanostructure SiO2 film was the most inclusive study on anti-reflection with omnidirectional and broadband characteristics. In this work, the three-dimensional silicon dioxide (SiO2) nanostructured thin film with different morphologies including vertical align, slant, spiral and thin films were fabricated by electron beam evaporation with glancing angle deposition (GLAD) on the glass slide and silicon wafer substrate. The morphological of the prepared samples were characterized by field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HRTEM). The transmission, omnidirectional and birefringence property of the nanostructure SiO2 films were investigated by UV-Vis-NIR spectrophotometer and variable angle spectroscopic ellipsometer (VASE). The spectrophotometer measurement was performed at normal incident angle and a full spectral range of 200 - 2000 nm. The angle dependent transmission measurements were investigated by rotating the specimen, with incidence angle defined relative to the surface normal of the prepared samples. This study demonstrates that the obtained SiO2 nanostructure film coated on glass slide substrate exhibits a higher transmission was 93% at normal incident angle. In addition, transmission measurement in visible wavelength and wide incident angles -80 to 80 were increased in comparison with the SiO2 thin film and glass slide substrate due to the transition in the refractive index profile from air to the nanostructure layer that improve the antireflection characteristics. The results clearly showed the enhanced omnidirectional and broadband characteristic of the three dimensional Si

Particle size and shape modification of hydroxyapatite nanostructures synthesized via a complexing agent-assisted route.

PubMed

Mohandes, Fatemeh; Salavati-Niasari, Masoud

2014-07-01

In this work, hydroxyapatite (HAP), Ca10(PO4)6(OH)2, nanostructures including nanorods, nanobundles and nanoparticles have been prepared via a simple precipitation method. In the present method, Ca(NO3)2·4H2O and (NH4)2HPO4 were used as calcium and phosphorus precursors, respectively. Besides, the Schiff bases derived from 2-hydroxyacetophenone and different diamines were used as complexing agents for the in situ formation of Ca(2+) complexes. The formation mechanism of 0-D and 1-D nanostructures of HAP was also considered. When the complexing agents could coordinate to the Ca(2+) ions through N and O atoms to form the [CaN2O2](2+) complexes, HAP nanoparticles were generated. On the other hand, nanorods and nanobundles of HAP were obtained by forming the [CaN2](2+) as well as [CaO2](2+) complexes in the reaction solution. This work is the first successful synthesis of pure HAP nanostructures in the presence of Schiff bases instead of using the common surfactants. Copyright © 2014 Elsevier B.V. All rights reserved.

Importance of polypyrrole in constructing 3D hierarchical carbon nanotube@MnO2 perfect core-shell nanostructures for high-performance flexible supercapacitors.

PubMed

Zhou, Jinyuan; Zhao, Hao; Mu, Xuemei; Chen, Jiayi; Zhang, Peng; Wang, Yaling; He, Yongmin; Zhang, Zhenxing; Pan, Xiaojun; Xie, Erqing

2015-09-21

This study reports the preparation of 3D hierarchical carbon nanotube (CNT) @MnO2 core-shell nanostructures under the assistance of polypyrrole (PPy). The as-prepared CNT@PPy@MnO2 core-shell structures show a perfect coating of MnO2 on each CNT and, more importantly, a robust bush-like pseudocapacitive shell to effectively increase the specific surface area and enhance the ion accessibility. As expected, a high specific capacity of 490-530 F g(-1) has been achieved from CNT@PPy@MnO2 single electrodes. And about 98.5% of the capacity is retained after 1000 charge/discharge cycles at a current density of 5 A g(-1). Furthermore, the assembled asymmetric CNT@PPy@MnO2//AC capacitors show the maximum energy density of 38.42 W h kg(-1) (2.24 mW h cm(-3)) at a power density of 100 W kg(-1) (5.83 mW cm(-3)), and they maintain 59.52% of the initial value at 10,000 W kg(-1) (0.583 W cm(-3)). In addition, the assembled devices show high cycling stabilities (89.7% after 2000 cycles for asymmetric and 87.2% for symmetric), and a high bending stability (64.74% after 200 bending tests). This ability to obtain high energy densities at high power rates while maintaining high cycling stability demonstrates that this well-designed structure could be a promising electrode material for high-performance supercapacitors.

Ultrasensitive electrochemical cocaine biosensor based on reversible DNA nanostructure.

PubMed

Sheng, Qinglin; Liu, Ruixiao; Zhang, Sai; Zheng, Jianbin

2014-01-15

We proposed an ultrasensitive electrochemical cocaine biosensor based on the three-dimensional (3D) DNA structure conversion of nanostructure from Triangular Pyramid Frustum (TPFDNA) to Equilateral Triangle (ETDNA). The presence of cocaine triggered the aptamer-composed DNA nanostructure change from "Close" to "Open", leading to obvious faradaic impedance changes. The unique properties with excellent stability and specific rigid structure of the 3D DNA nanostructure made the biosensing functions stable, sensitive, and regenerable. The Faradaic impedance responses were linearly related to cocaine concentration between 1.0 nM and 2.0 μM with a correlation coefficient of 0.993. The limit of detection was calculated to be 0.21 nM following IUPAC recommendations (3Sb/b). It is expected that the distinctive features of DNA nanostructure would make it potentially advantageous for a broad range of biosensing, bionanoelectronics, and therapeutic applications. Copyright © 2013 Elsevier B.V. All rights reserved.

nanostructures for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Rashad, M. M.; Shalan, A. E.

2014-08-01

Hierarchical architectures consisting of one-dimensional (1D) nanostructures are of great interest for potential use in energy and environmental applications in recent years. In this work, hierarchical tungsten oxide (WO3) has been synthesized via a facile hydrothermal route from ammonium metatungstate hydrate and implemented as photoelectrode for dye-sensitized solar cells. The urchin-like WO3 micro-patterns are constructed by self-organized nanoscale length 1D building blocks, which are single crystalline in nature, grown along (001) direction and confirm an orthorhombic crystal phase. The obtained powders were investigated by XRD, SEM, TEM and UV-Vis Spectroscopy. The photovoltaic performance of dye-sensitized solar cells based on WO3 photoanodes was investigated. With increasing the calcination temperature of the prepared nanopowders, the light-electricity conversion efficiency ( η) was increased. The results were attributed to increase the crystallinity of the particles and ease of electron movement. The DSSC based on hierarchical WO3 showed a short-circuit current, an open-circuit voltage, a fill factor, and a conversion efficiency of 4.241 mA/cm2, 0.656 V, 66.74, and 1.85 %, respectively.

Boehmite nanostructures preparation by hydrothermal method from anodic aluminium oxide membrane.

PubMed

Yang, X; Wang, J Y; Pan, H Y

2009-02-01

Boehmite nanostructures were successfully synthesized from porous anodic aluminium oxide (AAO) membrane by a simple and efficient hydro-thermal method. The experiment used high purity alumina as raw material, and the whole reaction process avoided superfluous impurities to be introduced. Thus, the purity of Boehmite products was ensured. The examinations of the morphology and structure were carried out by atomic force microscope (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Composition of the specimens was analyzed using energy dispersive X-ray spectroscope (EDX) and X-ray diffraction (XRD). Based on these observations the growth process was analyzed.

Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel.

PubMed

Gund, Girish S; Dubal, Deepak P; Chodankar, Nilesh R; Cho, Jun Y; Gomez-Romero, Pedro; Park, Chan; Lokhande, Chandrakant D

2015-07-24

The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg(-1), about 2-fold of higher energy density (41.8 Wh kg(-1)) than symmetric SC and excellent mechanical flexibility. Furthermore, the "real-life" demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel

PubMed Central

Gund, Girish S.; Dubal, Deepak P.; Chodankar, Nilesh R.; Cho, Jun Y.; Gomez-Romero, Pedro; Park, Chan; Lokhande, Chandrakant D.

2015-01-01

The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0–1 V and 0–2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg−1, about 2-fold of higher energy density (41.8 Wh kg−1) than symmetric SC and excellent mechanical flexibility. Furthermore, the “real-life” demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC. PMID:26208144

Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel

NASA Astrophysics Data System (ADS)

Gund, Girish S.; Dubal, Deepak P.; Chodankar, Nilesh R.; Cho, Jun Y.; Gomez-Romero, Pedro; Park, Chan; Lokhande, Chandrakant D.

2015-07-01

The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg-1, about 2-fold of higher energy density (41.8 Wh kg-1) than symmetric SC and excellent mechanical flexibility. Furthermore, the “real-life” demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

Realizing a facile and environmental-friendly fabrication of high-performance multi-crystalline silicon solar cells by employing ZnO nanostructures and an Al2O3 passivation layer

PubMed Central

Chen, Hong-Yan; Lu, Hong-Liang; Sun, Long; Ren, Qing-Hua; Zhang, Hao; Ji, Xin-Ming; Liu, Wen-Jun; Ding, Shi-Jin; Yang, Xiao-Feng; Zhang, David Wei

2016-01-01

Nowadays, the multi-crystalline silicon (mc-Si) solar cells dominate the photovoltaic industry. However, the current acid etching method on mc-Si surface used by firms can hardly suppress the average reflectance value below 25% in the visible light spectrum. Meanwhile, the nitric acid and the hydrofluoric contained in the etching solution is both environmental unfriendly and highly toxic to human. Here, a mc-Si solar cell based on ZnO nanostructures and an Al2O3 spacer layer is demonstrated. The eco-friendly fabrication is realized by low temperature atomic layer deposition of Al2O3 layer as well as ZnO seed layer. Moreover, the ZnO nanostructures are prepared by nontoxic and low cost hydro-thermal growth process. Results show that the best passivation quality of the n+ -type mc-Si surface can be achieved by balancing the Si dangling bond saturation level and the negative charge concentration in the Al2O3 film. Moreover, the average reflectance on cell surface can be suppressed to 8.2% in 400–900 nm range by controlling the thickness of ZnO seed layer. With these two combined refinements, a maximum solar cell efficiency of 15.8% is obtained eventually. This work offer a facile way to realize the environmental friendly fabrication of high performance mc-Si solar cells. PMID:27924911

Realizing a facile and environmental-friendly fabrication of high-performance multi-crystalline silicon solar cells by employing ZnO nanostructures and an Al2O3 passivation layer

NASA Astrophysics Data System (ADS)

Chen, Hong-Yan; Lu, Hong-Liang; Sun, Long; Ren, Qing-Hua; Zhang, Hao; Ji, Xin-Ming; Liu, Wen-Jun; Ding, Shi-Jin; Yang, Xiao-Feng; Zhang, David Wei

2016-12-01

Nowadays, the multi-crystalline silicon (mc-Si) solar cells dominate the photovoltaic industry. However, the current acid etching method on mc-Si surface used by firms can hardly suppress the average reflectance value below 25% in the visible light spectrum. Meanwhile, the nitric acid and the hydrofluoric contained in the etching solution is both environmental unfriendly and highly toxic to human. Here, a mc-Si solar cell based on ZnO nanostructures and an Al2O3 spacer layer is demonstrated. The eco-friendly fabrication is realized by low temperature atomic layer deposition of Al2O3 layer as well as ZnO seed layer. Moreover, the ZnO nanostructures are prepared by nontoxic and low cost hydro-thermal growth process. Results show that the best passivation quality of the n+ -type mc-Si surface can be achieved by balancing the Si dangling bond saturation level and the negative charge concentration in the Al2O3 film. Moreover, the average reflectance on cell surface can be suppressed to 8.2% in 400-900 nm range by controlling the thickness of ZnO seed layer. With these two combined refinements, a maximum solar cell efficiency of 15.8% is obtained eventually. This work offer a facile way to realize the environmental friendly fabrication of high performance mc-Si solar cells.

DNA-nanostructure-assembly by sequential spotting

PubMed Central

2011-01-01

Background The ability to create nanostructures with biomolecules is one of the key elements in nanobiotechnology. One of the problems is the expensive and mostly custom made equipment which is needed for their development. We intended to reduce material costs and aimed at miniaturization of the necessary tools that are essential for nanofabrication. Thus we combined the capabilities of molecular ink lithography with DNA-self-assembling capabilities to arrange DNA in an independent array which allows addressing molecules in nanoscale dimensions. Results For the construction of DNA based nanostructures a method is presented that allows an arrangement of DNA strands in such a way that they can form a grid that only depends on the spotted pattern of the anchor molecules. An atomic force microscope (AFM) has been used for molecular ink lithography to generate small spots. The sequential spotting process allows the immobilization of several different functional biomolecules with a single AFM-tip. This grid which delivers specific addresses for the prepared DNA-strand serves as a two-dimensional anchor to arrange the sequence according to the pattern. Once the DNA-nanoarray has been formed, it can be functionalized by PNA (peptide nucleic acid) to incorporate advanced structures. Conclusions The production of DNA-nanoarrays is a promising task for nanobiotechnology. The described method allows convenient and low cost preparation of nanoarrays. PNA can be used for complex functionalization purposes as well as a structural element. PMID:22099392

Nanostructures having high performance thermoelectric properties

DOEpatents

Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I.; Chen, Renkun; Delgado, Raul Diaz

2015-12-22

The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

Nanostructures having high performance thermoelectric properties

DOEpatents

Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I; Chen, Renkun; Delgado, Raul Diaz

2014-05-20

The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

Tunable Electromagnetic Coupling in Plasmonic Nanostructures Mediated by Thermoresponsive Polymer Brushes.

PubMed

Nguyen, Mai; Kanaev, Andrei; Sun, Xiaonan; Lacaze, Emmanuelle; Lau-Truong, Stéphanie; Lamouri, Aazdine; Aubard, Jean; Felidj, Nordin; Mangeney, Claire

2015-11-24

A smart and highly SERS-active plasmonic platform was designed by coupling regular arrays of nanotriangles to colloidal gold nanorods via a thermoresponsive polymer spacer (poly(N-isopropylacrylamide), PNIPAM). The substrates were prepared by combining a top-down and a bottom-up approach based on nanosphere lithography, surface-initiated controlled radical polymerization, and colloidal assembly. This multistep strategy provided regular hexagonal arrays of nanotriangles functionalized by polymer brushes and colloidal gold nanorods, confined exclusively on the nanotriangle surface. Interestingly, one could finely tune the gold nanorod impregnation on the polymer-coated nanostructures by adjusting the polymer layer thickness, leading to highly coupled plasmonic systems for intense SERS signal. Moreover, the thermoresponsive properties of the PNIPAM brushes could be wisely handled in order to monitor the SERS activity of the nanostructures coupled via this polymer spacer. The coupled hybrid plasmonic nanostructures designed in this work are therefore very promising smart platforms for the sensitive detection of analytes by SERS.

Controlled synthesis of nanostructured molybdenum oxide electrodes for high performance supercapacitor devices

NASA Astrophysics Data System (ADS)

Maheswari, Nallappan; Muralidharan, Gopalan

2017-09-01

Well defined crystallographic and one dimensional morphological structure of molybdenum oxide were successfully synthesized by adjusting the duration of hydrothermal treatment. The prepared molybdenum oxide was examined through XRD, SEM, FTIR, TEM, BET and electrochemical studies. The XRD patterns illustrate that MoOx prepared by variying the hydrothermal reaction time are in different crystallographic structure of MoyOx (Mo8O23 and MoO3). SEM studies reveal the different morphological structures ranging from flake like morphology to nanorods. TEM images confirm the excellent nanorod structure. The nanorod structure ensures good cyclic behaviour with maximum capacitance of 1080 F g-1 at a current density of 2 A g-1. This large capacity of the MoO3 nanostructures enabled fabrication of symmetric and asymmertic supercapacitor devices. The asymmertic device exhibits a maximum specific capacitance of 145 F g-1 at 2 mV s-1 with highest energy density of 38.6 W h kg-1 at 374.7 W kg-1 power density.

Extrinsic contributions to the dielectric response in sintered BaTiO3 nanostructures in paraelectric and ferroelectric regimes

NASA Astrophysics Data System (ADS)

Jaffari, G. Hassnain; Rehman, Atiq ur; Iqbal, Asad M.; Awan, M. S.; Saleemi, Mohsin

2017-11-01

Post sintering studies of BaTiO3 (BTO) nanoparticles are presented in detail. Bulk nanostructures were prepared via three different compaction processes, namely, uniaxial cold pressing (UCP), Cold Isostatic Pressing (CIP) and Spark Plasma Sintering (SPS). Effect of compaction technique on microstructures have been investigated and correlated with electrical response for each sample. In addition to the transport properties, temperature and frequency dependent dielectric response of variously sintered samples and bulk counterpart was recorded. Several aspects have been identified that are essential to be taken into account in order to completely understand physical processes. Drastically distinct features were observed in paraelectric (PE) regime well above ferroelectric (FE)-PE transition temperature. These features include intra grain conduction with a reduction in the magnitude of PE to FE peak dielectric constant magnitude. Role of strain, grain boundary conduction associated with observation of Maxwell Wagner relaxation and hopping conduction in dielectric and ferroelectric response have been observed and discussed. Densification with presence of oxygen vacancies, significantly enhances conductivity associated with the hopping of the carriers, in turn deteriorated ferroelectric response.

Three-Dimensional ZnO Hierarchical Nanostructures: Solution Phase Synthesis and Applications

PubMed Central

Wang, Xiaoliang; Ahmad, Mashkoor

2017-01-01

Zinc oxide (ZnO) nanostructures have been studied extensively in the past 20 years due to their novel electronic, photonic, mechanical and electrochemical properties. Recently, more attention has been paid to assemble nanoscale building blocks into three-dimensional (3D) complex hierarchical structures, which not only inherit the excellent properties of the single building blocks but also provide potential applications in the bottom-up fabrication of functional devices. This review article focuses on 3D ZnO hierarchical nanostructures, and summarizes major advances in the solution phase synthesis, applications in environment, and electrical/electrochemical devices. We present the principles and growth mechanisms of ZnO nanostructures via different solution methods, with an emphasis on rational control of the morphology and assembly. We then discuss the applications of 3D ZnO hierarchical nanostructures in photocatalysis, field emission, electrochemical sensor, and lithium ion batteries. Throughout the discussion, the relationship between the device performance and the microstructures of 3D ZnO hierarchical nanostructures will be highlighted. This review concludes with a personal perspective on the current challenges and future research. PMID:29137195

Chemistry of surface nanostructures in lead precursor-rich PbZr0.52Ti0.48O3 sol-gel films

NASA Astrophysics Data System (ADS)

Gueye, I.; Le Rhun, G.; Gergaud, P.; Renault, O.; Defay, E.; Barrett, N.

2016-02-01

We present a study of the chemistry of the nanostructured phase at the surface of lead zirconium titanate PbZr0.52Ti0.48O3 (PZT) films synthesized by sol-gel method. In sol-gel synthesis, excess lead precursor is used to maintain the target stoichiometry. Surface nanostructures appear at 10% excess whereas 30% excess inhibits their formation. Using the surface-sensitive, quantitative X-ray photoelectron spectroscopy and glancing angle X-ray diffraction we have shown that the chemical composition of the nanostructures is ZrO1.82-1.89 rather than pyrochlore often described in the literature. The presence of a possibly discontinuous layer of wide band gap ZrO1.82-1.89 could be of importance in determining the electrical properties of PZT-based metal-insulator-metal heterostructures.

Modification of nanostructured calcium carbonate for efficient gene delivery.

PubMed

Zhao, Dong; Wang, Chao-Qun; Zhuo, Ren-Xi; Cheng, Si-Xue

2014-06-01

In this study, a facile method to modify nanostructured calcium carbonate (CaCO3) gene delivery systems by adding calcium phosphate (CaP) component was developed. CaCO3/CaP/DNA nanoparticles were prepared by the co-precipitation of Ca(2+) ions with plasmid DNA in the presence of carbonate and phosphate ions. For comparison, CaCO3/DNA nanoparticles and CaP/DNA co-precipitates were also prepared. The effects of carbonate ion/phosphate ion (CO3(2-)/PO4(3-)) ratio on the particle size and gene delivery efficiency were investigated. With an appropriate CO3(2-)/PO4(3-) ratio, the co-existence of carbonate and phosphate ions could control the size of co-precipitates effectively, and CaCO3/CaP/DNA nanoparticles with a decreased size and improved stability could be obtained. The in vitro gene transfections mediated by different nanoparticles in 293T cells and HeLa cells were carried out, using pGL3-Luc as a reporter plasmid. The gene transfection efficiency of CaCO3/CaP/DNA nanoparticles could be significantly improved as compared with CaCO3/DNA nanoparticles and CaP/DNA co-precipitates. The confocal microscopy study indicated that the cellular uptake and nuclear localization of CaCO3/CaP/DNA nanoparticles were significantly enhanced as compared with unmodified CaCO3/DNA nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

Epitaxial graphene growth on FIB patterned 3C-SiC nanostructures on Si (111): reducing milling damage.

PubMed

Amjadipour, Mojtaba; MacLeod, Jennifer; Lipton-Duffin, Josh; Iacopi, Francesca; Motta, Nunzio

2017-08-25

Epitaxial growth of graphene on SiC is a scalable procedure that does not require any further transfer step, making this an ideal platform for graphene nanostructure fabrication. Focused ion beam (FIB) is a very promising tool for exploring the reduction of the lateral dimension of graphene on SiC to the nanometre scale. However, exposure of graphene to the Ga + beam causes significant surface damage through amorphisation and contamination, preventing epitaxial graphene growth. In this paper we demonstrate that combining a protective silicon layer with FIB patterning implemented prior to graphene growth can significantly reduce the damage associated with FIB milling. Using this approach, we successfully achieved graphene growth over 3C-SiC/Si FIB patterned nanostructures.

Enhanced photovoltaic performance of inverted pyramid-based nanostructured black-silicon solar cells passivated by an atomic-layer-deposited Al2O3 layer.

PubMed

Chen, Hong-Yan; Lu, Hong-Liang; Ren, Qing-Hua; Zhang, Yuan; Yang, Xiao-Feng; Ding, Shi-Jin; Zhang, David Wei

2015-10-07

Inverted pyramid-based nanostructured black-silicon (BS) solar cells with an Al2O3 passivation layer grown by atomic layer deposition (ALD) have been demonstrated. A multi-scale textured BS surface combining silicon nanowires (SiNWs) and inverted pyramids was obtained for the first time by lithography and metal catalyzed wet etching. The reflectance of the as-prepared BS surface was about 2% lower than that of the more commonly reported upright pyramid-based SiNW BS surface over the whole of the visible light spectrum, which led to a 1.7 mA cm(-2) increase in short circuit current density. Moreover, the as-prepared solar cells were further passivated by an ALD-Al2O3 layer. The effect of annealing temperature on the photovoltaic performance of the solar cells was investigated. It was found that the values of all solar cell parameters including short circuit current, open circuit voltage, and fill factor exhibit a further increase under an optimized annealing temperature. Minority carrier lifetime measurements indicate that the enhanced cell performance is due to the improved passivation quality of the Al2O3 layer after thermal annealing treatments. By combining these two refinements, the optimized SiNW BS solar cells achieved a maximum conversion efficiency enhancement of 7.6% compared to the cells with an upright pyramid-based SiNWs surface and conventional SiNx passivation.

Hybridized boron-carbon nitride fibrous nanostructures on Ni substrates

NASA Astrophysics Data System (ADS)

Yap, Yoke Khin; Yoshimura, Masashi; Mori, Yusuke; Sasaki, Takatomo

2002-04-01

Stoichiometric BC2N films can be deposited on Si (100) at 800 °C, however, they are phase separated as pure carbon and BN phases. Likewise, hybridized boron-carbon nitride (BCN) films can be synthesized on Ni substrates. On Ni, the carbon and BN phases are hybridized through carbon nitride and boron carbide bonds. These films appeared as fibrous nanostructures. Evidence indicates that the Ni substrate acts as a sink for the carbon and forces the carbon composites to grow on top of the B and N atoms. However, as these films are grown thicker, phase separation occurs again. These results indicate that hybridized BCN phases should now be regarded as semiconducting or superhard nanostructures. High-temperature deposition on Ni substrates might be a solution to the obstacle of preparing hybridized BCN phases.

Composite WO 3/TiO 2 nanostructures for high electrochromic activity

DOE PAGES

Reyes-Gil, Karla R.; Stephens, Zachary D.; Stavila, Vitalie; ...

2015-01-06

A composite material consisting of TiO 2 nanotubes (NT) with WO 3 electrodeposited on its surface has been fabricated, detached from its Ti substrate, and attached to a fluorine-doped tin oxide (FTO) film on glass for application to electrochromic (EC) reactions. Several adhesion layers were tested, finding that a paste of TiO 2 made from commercially available TiO 2 nanoparticles creates an interface for the TiO 2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length and WOmore » 3 concentration on the EC performance were studied. As a result, the composite WO 3/TiO 2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast, and longer memory time compared with the pure WO 3 and TiO 2 materials« less

Facile synthesis of hierarchical gold nanostructures and their catalytic application

NASA Astrophysics Data System (ADS)

Ma, Ying; Siang Yi, Edward Ng

2016-08-01

We demonstrate a one-step, surfactant-free method to prepare gold (Au) nanostructures using a synthesized aniline (ANI) derivative N-(3-amidino)-aniline (NAAN) as a reducing agent. By simply mixing NAAN with a Au precursor, raspberry-like Au particles (RSPs) were formed. The presence of Ag+ resulted in the formation of Au nanoflowers (AuNFs). The size and shape of the AuNFs can be tuned by the reaction conditions such as the NAAN/HAuCl4 ratio, the temperature and the solvent composition. Under the same reaction conditions, bowling-pin-like particles (BPLPs) were reported for the first time using commercial ANI as a reducing agent. The AuNFs exhibited good ability to oxidize peroxidase substrate 3, 3‧, 5, 5‧-tetramethylbenzidine (TMB) by H2O2, allowing them as a peroxidase mimetic.

From thermoelectric bulk to nanomaterials: Current progress for Bi 2 Te 3 and CoSb 3: From thermoelectric bulk to nanomaterials

DOE PAGES

Peranio, N.; Eibl, O.; Bäßler, S.; ...

2015-10-29

We synthesized Bi 2Te 3 and CoSb 3 based nanomaterials and their thermoelectric, structural, and vibrational properties analyzed to assess and reduce ZT-limiting mechanisms. The same preparation and/or characterization methods were applied in the different materials systems. Single-crystalline, ternary p-type Bi 15Sb 29Te 56, and n-type Bi 38Te 55Se 7 nanowires with power factors comparable to nanostructured bulkmaterialswere prepared by potential-pulsed electrochemical deposition in a nanostructured Al 2O 3 matrix. p-type Sb 2Te 3, n-type Bi 2Te 3, and n-type CoSb 3 thin films were grown at room temperature using molecular beam epitaxy and were subsequently annealed at elevated temperatures.more » It yielded polycrystalline, single phase thin films with optimized charge carrier densities. In CoSb 3 thin films the speed of sound could be reduced by filling the cage structure with Yb and alloying with Fe yielded p-type material. Bi 2(Te 0.91Se 0.09) 3/SiC and (Bi 0.26Sb 0.74) 2Te 3/SiC nanocomposites with low thermal conductivities and ZT values larger than 1 were prepared by spark plasma sintering. Nanostructure, texture, chemical composition, as well as electronic and phononic excitations were investigated by X-ray diffraction, nuclear resonance scattering, inelastic neutron scattering, M ossbauer spectroscopy, and transmission electron microscopy. Furthermore, for Bi 2Te 3 materials, ab-initio calculations together with equilibrium and non-equilibrium molecular dynamics simulations for point defects yielded their formation energies and their effect on lattice thermal conductivity, respectively. Current advances in thermoelectric Bi 2Te 3 and CoSb 3 based nanomaterials are summarized. Advanced synthesis and characterization methods and theoreticalmodelingwere combined to assess and reduce ZT-limiting mechanisms in these materials.« less

The Process of Nanostructuring of Metal (Iron) Matrix in Composite Materials for Directional Control of the Mechanical Properties

PubMed Central

Zemtsova, Elena

2014-01-01

We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1–50 nm. This material can be represented as the material type “frame in the frame” that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology. PMID:24695459

The process of nanostructuring of metal (iron) matrix in composite materials for directional control of the mechanical properties.

PubMed

Zemtsova, Elena; Yurchuk, Denis; Smirnov, Vladimir

2014-01-01

We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1-50 nm. This material can be represented as the material type "frame in the frame" that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology.

Effects of Silica Nanostructures in Poly(ethylene oxide)-Based Composite Polymer Electrolytes.

PubMed

Mohanta, Jagdeep; Anwar, Shahid; Si, Satyabrata

2016-06-01

The present work describes the synthesis of some poly(ethylene oxide)-based nanocomposite polymer electrolyte films using various silica nanostructures as the inorganic filler by simple solution mixing technique, in which the nature of the silica nanostructures play a vital role in modulating their electrochemical performances at room temperature. The silica nanostructures are prepared by ammonical hydrolysis of tetraethyl orthosilicate following the modified St6ber method. The resulting films are characterized by X-ray diffraction and differential scanning calorimeter to study their crystallinity. Room temperature AC impedance spectroscopy is utilized to determine the Li+ ion conductivity of the resulting films. The observed conductivity values of various NCPE films depend on the nature of silica filling as well as on their surface characteristics and also on the varying PEO-Li+ ratio, which is observed to be in the order of 10(-7)-10(-6) S cm(-1).

Synthesis of belt-like BiOBr hierarchical nanostructure with high photocatalytic performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Haiping; Liu, Jingyi; Hu, Tingxia

2016-05-15

Highlights: • BiOBr hierarchical nanobelts (NBs) were solvothermally prepared. • NBs show higher specific surface area and photoabsorption than BiOBr nanosheets. • NBs exhibit higher photoactivity than the nanosheets. - Abstract: One-dimensional (1D) bismuth oxyhalide (BiOX) hierarchical nanostructures are always difficult to prepare. Herein, we report, for the first time, a simple synthesis of BiOBr nanobelts (NBs) via a facile solvothermal route, using bismuth subsalicylate as the template and bismuth source. The BiOBr nanobelts are composed of irregular single crystal nanoparticles with highly exposed (0 1 0) facets. Compared with the BiOBr nanosheets (NSs) with dominant exposed (0 0 1)more » facets, they exhibit higher photocatalytic activity toward degradation of Rhodamine B and Methylene Blue under visible light irradiation. The higher photocatalytic performance of BiOBr NBs arises from their larger specific surface area and higher photoabsorption capability. This study provides a simple route for synthesis of belt-like Bi-based hierarchical nanostructures.« less

TiO{sub 2} flower-like nanostructures decorated with CdS/PbS nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trenczek-Zajac, Anita, E-mail: anita.trenczek-zajac@agh.edu.pl; Kusior, Anna; Lacz, Agnieszka

Highlights: • TiO{sub 2} flower-like nanostructures were prepared with the use of Ti foil and 30% H{sub 2}O{sub 2}. • QDs of CdS and PbS were deposited using the SILAR method. • The SILAR method makes it possible to control the size of QDs. • Band gap energy of CdS was found to be 2.35 eV. • Sensitization of TiO{sub 2} with CdS or PbS improves the photoelectrochemical properties. - Abstract: Flower-like nanostructures of TiO{sub 2} were prepared by immersing Ti foil in 30% H{sub 2}O{sub 2} at 80 °C for times varying from 15 to 240 min. Upon annealingmore » at 450 °C in an Ar atmosphere, the received amorphous samples crystallized in an anatase structure with rutile as a minority phase. SEM images revealed that partially formed flowers were present at the surface of the prepared samples as early as after 15 min of immersion. The size of the individual flowers increased from 400–800 nm after 15 min of reaction to 2.5–6.0 μm after 240 min. It was also found that surface is very rough and surface development is considerable. After 45 min of immersion, the nanoflowers were sensitized with CdS and PbS quantum dots (QDs-CdS/QDs-PbS) deposited using the SILAR method from water- and methanol-based precursor solutions at different concentrations (0.001–0.1 M). QDs-CdS crystallized in the hawleyite structure, while QDs-PbS in the galena form. SEM analysis showed the tendency of quantum dots to agglomerate at high concentrations of the precursor in water-based solutions. QDs obtained from methanol-based solutions were uniformly distributed. The produced QDs-PbS were smaller than QDs-CdS. Based on the optical reflectance spectra, the band-gap energies of TiO{sub 2} nanostructures with and without QDs were calculated to be 3.32 eV for flower-like TiO{sub 2} nanostructures and 2.35 eV for QDs-CdS. The photoelectrochemical behaviour of nanoflowers was found to improve significantly after the deposition of QDs-CdS.« less

Fabrication and characterization of the noble metal nanostructures on the GaAs surface

NASA Astrophysics Data System (ADS)

Gladskikh, Polina V.; Gladskikh, Igor A.; Toropov, Nikita A.; Vartanyan, Tigran A.

2016-04-01

Self-assembled silver, gold, and copper nanostructures on the monocrystalline GaAs (100) wafer surface were obtained via physical vapor deposition and characterized by optical reflection spectroscopy, scanning electron microscopy, and current-voltage curve measurements. Reflection spectra of the samples with Ag equivalent thicknesses of 2, 5, 7.5, and 10 nm demonstrated wide plasmonic bands in the visible range of spectra. Thermal annealing of the nanostructures led to narrowing of the plasmonic bands of Au and Ag nanostructures caused by major transformations of the film morphology. While the as prepared films predominantly had a small scale labyrinth structure, after annealing well-separated nanoislands are formed on the gallium arsenide surface. A clear correlation between films morphology and their optical and electrical properties is elucidated. Annealing of the GaAs substrate with Ag nanostructures at 100 °C under control of the resistivity allowed us to obtain and fix the structure at the percolation threshold. It is established that the samples at the percolation threshold possess the properties of resistance switching and hysteresis.

Nanostructuring of thin Au films deposited on ordered Ti templates for applications in SERS

NASA Astrophysics Data System (ADS)

Grochowska, Katarzyna; Siuzdak, Katarzyna; Macewicz, Łukasz; Skiba, Franciszek; Szkoda, Mariusz; Karczewski, Jakub; Burczyk, Łukasz; Śliwiński, Gerard

2017-10-01

In this work the results on thermal nanostructuring of the Au films on Ti templates as well as morphology and optical properties of the obtained structures are reported. The bimetal nanostructures are fabricated in a multi-step process. First, the titania nanotubes are produced on the surface of Ti foil by anodization in an ethylene glycol-water solution containing fluoride ions. This is followed by chemical etching in oxalic acid and results in a highly ordered dimpled surface. Subsequently, thin gold films (5-20 nm) are deposited onto prepared Ti substrates by magnetron sputtering. The as-prepared layers are then dewetted by the UV nanosecond laser pulses or alternatively in the furnace (temperature < 500 °C). The SEM inspection reveals formation of honeycomb nanostructures (cavity diameter: ∼100 nm) covered with Au nanoparticles (NPs). It is observed that both the laser annealing and continuous thermal treatment in furnace can lead to the creation of NPs inside every Ti dimple and result in uniform coating of the whole area of structured templates. The size and localization of NPs obtained via both dewetting processes as well as their shape can be tuned by the annealing time and the laser processing parameters and also by initial thickness of Au layer and presence of the dimples themselves in the substrate. Results confirm that the prepared material can be used as substrate for SERS (Surface Enhanced Raman Spectroscopy).

Nanostructured giant magneto-impedance multilayers deposited onto flexible substrates for low pressure sensing

PubMed Central

2012-01-01

Nanostructured FeNi-based multilayers are very suitable for use as magnetic sensors using the giant magneto-impedance effect. New fields of application can be opened with these materials deposited onto flexible substrates. In this work, we compare the performance of samples prepared onto a rigid glass substrate and onto a cyclo olefin copolymer flexible one. Although a significant reduction of the field sensitivity is found due to the increased effect of the stresses generated during preparation, the results are still satisfactory for use as magnetic field sensors in special applications. Moreover, we take advantage of the flexible nature of the substrate to evaluate the pressure dependence of the giant magneto-impedance effect. Sensitivities up to 1 Ω/Pa are found for pressures in the range of 0 to 1 Pa, demostrating the suitability of these nanostructured materials deposited onto flexible substrates to build sensitive pressure sensors. PMID:22525096

Double NIR laser stimulation and enhancing the thermal sensitivity of Er3+/Tm3+/Nd3+ doped multilayer core-shell nanoparticles.

PubMed

Ba, Zhaojing; Hu, Min; Zhao, Yiming; Wang, Yiqing; Wang, Jing; Zhang, Zhenxi

2018-08-31

Non-contact thermal sensors are important devices to study cellular processes and monitor temperature in vivo. Herein, a novel highly sensitive nanothermometer based on NaYF 4 :Yb,Er@ NaYF 4 @NaYF 4 :Yb,Tm@ NaYF 4 :Nd (denoted as Er@Y@Tm@Nd) was prepared by a facile solvothermal method. When excited by the near-infrared (NIR) light of 808 and 980 nm, the as-prepared Er@Y@Tm@Nd nanoparticles could emit both blue and green light, respectively, since the lanthanide cations responsible for these emissions are gathered inside this nanostructure. The green and blue light intensity ratio exhibits obvious temperature dependence in the range of the physiological temperature. Additionally, the fluorescence intensity of Er 3+ and Tm 3+ are also greatly enhanced due to the multilayer structure that implies avoiding the Er 3+ and Tm 3+ energy cross-relaxation by introduction of a NaYF 4 wall between them. The as-prepared core-shell-shell-shell structure with Er 3+ and Tm 3+ in different layers improves dozens of times of the thermal sensitivity based on the non-thermal coupling levels of the probe: the maximum values for the sensitivity are 2.95% K -1 (I Er-521 /I Tm-450 ) and 6.30% K -1 (I Tm-474 /I Er-541 ) when excited by 980 and 808 nm laser sources, respectively. These values are well above those previously reported (<0.7% K -1 ), indicating that the prepared nanostructures are temperature sensors with excellent thermal sensitivity and sensitive to NIR wavelength excitation that makes them highly preferred for thermal detection.

Bond topography and nanostructure of hydrogenated fullerene-like carbon films: A comparative study

NASA Astrophysics Data System (ADS)

Wang, Yongfu; Gao, Kaixiong; Shi, Jing; Zhang, Junyan

2016-09-01

Fullerene-like nanostructural hydrogenated amorphous carbon (FL-C:H) films were prepared by dc- and pulse- plasma enhanced chemical vapor deposition technique (PECVD). Both the films exhibit relatively stresses (0.63 GPa) in spite of their FL features and nanostructural bonding configurations, especially the pentagonal carbon rings. The creation of pentagonal rings is not fully driven by thermodynamics, but is closely related to compressive stress determined by the ion bombardment at the discharged state of the pulse- and dc- discharged plasmas methods. The dc method leads to FL's basal planes which contain less cross-linkages, and causes amorphous strongly hydrogenated structures.

Formation of superhydrophobic/superhydrophilic patterns by combination of nanostructure-imprinted perfluoropolymer and nanostructured silicon oxide for biological droplet generation

NASA Astrophysics Data System (ADS)

Kobayashi, Taizo; Shimizu, Kazunori; Kaizuma, Yoshihiro; Konishi, Satoshi

2011-03-01

In this letter, we report a technology for fabricating superhydrophobic/superhydrophilic patterns using a combination of a nanostructure-imprinted perfluoropolymer and nanostructured silicon oxide. In our previous study, we used a combination of hydrophobic and superhydrophilic materials. However, it was difficult to split low-surface-tension liquids such as biological liquids into droplets solely using hydrophobic/hydrophilic patterns. In this study, the contact angle of the hydrophobic region was enhanced from 109.3° to 155.6° by performing nanostructure imprinting on a damage-reduced perfluoropolymer. The developed superhydrophobic/superhydrophilic patterns allowed the splitting of even those media that contained fetal bovine serum into droplets of a desired shape.

Tailoring galvanic replacement reaction for the preparation of Pt/Ag bimetallic hollow nanostructures with controlled number of voids.

PubMed

Zhang, Weiqing; Yang, Jizheng; Lu, Xianmao

2012-08-28

Here we report the synthesis of Pt/Ag bimetallic nanostructures with controlled number of void spaces via a tailored galvanic replacement reaction (GRR). Ag nanocubes (NCs) were employed as the template to react with Pt ions in the presence of HCl. The use of HCl in the GRR caused rapid precipitation of AgCl, which grew on the surface of Ag NCs and acted as a removable secondary template for the deposition of Pt. The number of nucleation sites for AgCl was tailored by controlling the amount of HCl added to the Ag NCs or by introducing PVP to the reaction. This strategy led to the formation of Pt/Ag hollow nanoboxes, dimers, multimers, or popcorn-shaped nanostructures consisting of one, two, or multiple hollow domains. Due to the presence of large void space and porous walls, these nanostructures exhibited high surface area and improved catalytic activity for methanol oxidation reaction.

Nanostructured 3D constructs based on chitosan and chondroitin sulphate multilayers for cartilage tissue engineering.

PubMed

Silva, Joana M; Georgi, Nicole; Costa, Rui; Sher, Praveen; Reis, Rui L; Van Blitterswijk, Clemens A; Karperien, Marcel; Mano, João F

2013-01-01

Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and chondroitin sulphate (CS) on either bidimensional glass surfaces or 3D packet of paraffin spheres. 2D CHT/CS multi-layered constructs proved to support the attachment and proliferation of bovine chondrocytes (BCH). The technology was transposed to 3D level and CHT/CS multi-layered hierarchical scaffolds were retrieved after paraffin leaching. The obtained nanostructured 3D constructs had a high porosity and water uptake capacity of about 300%. Dynamical mechanical analysis (DMA) showed the viscoelastic nature of the scaffolds. Cellular tests were performed with the culture of BCH and multipotent bone marrow derived stromal cells (hMSCs) up to 21 days in chondrogenic differentiation media. Together with scanning electronic microscopy analysis, viability tests and DNA quantification, our results clearly showed that cells attached, proliferated and were metabolically active over the entire scaffold. Cartilaginous extracellular matrix (ECM) formation was further assessed and results showed that GAG secretion occurred indicating the maintenance of the chondrogenic phenotype and the chondrogenic differentiation of hMSCs.

Nanostructure of highly aromatic graphene nanosheets -- From optoelectronics to electrochemical energy storage applications

NASA Astrophysics Data System (ADS)

Biswas, Sanjib

The exceptional electrical properties along with intriguing physical and chemical aspects of graphene nanosheets can only be realized by nanostructuring these materials through the homogeneous and orderly distribution of these nanosheets without compromising the aromaticity of the native basal plane. Graphene nanosheets prepared by direct exfoliation as opposed to the graphene oxide route are necessary in order to preserve the native chemical properties of graphene basal planes. This research has been directed at optimally combining the diverse physical and chemical aspects of graphene nanosheets such as particle size, surface area and edge chemistry to fabricate nanostructured architectures for optoelectronics and high power electrochemical energy storage applications. In the first nanostructuring effort, a monolayer of these ultrathin, highly hydrophobic graphene nanosheets was prepared on a large area substrate via self-assembly at the liquid-liquid interface. Driven by the minimization of interfacial energy these planar graphene nanosheets produce a close packed monolayer structure at the liquid-liquid interface. The resulting monolayer film exhibits high electrical conductivity of more than 1000 S/cm and an optical transmission of more than 70-80% between wavelengths of 550 nm and 2000 nm making it an ideal candidate for optoelectronic applications. In the second part of this research, nanostructuring was used to create a configuration suitable for supercapacitor applications. A free standing, 100% binder free multilayer, flexible film consisting of monolayers of graphene nanosheets was prepared by utilizing the van der Waals forces of attraction between the basal plans of the graphene nanosheets coupled with capillary driven and drying-induced collapse. A major benefit in this approach is that the graphene nanosheet's attractive physical and chemical characteristics can be synthesized into an architecture consisting of large and small nanosheets to create an

Segmented metallic nanostructures, homogeneous metallic nanostructures and methods for producing same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Stanislaus; Koenigsmann, Christopher

The present invention includes a method of producing a segmented 1D nanostructure. The method includes providing a vessel containing a template wherein on one side of the template is a first metal reagent solution and on the other side of the template is a reducing agent solution, wherein the template comprises at least one pore; allowing a first segment of a 1D nanostructure to grow within a pore of the template until a desired length is reached; replacing the first metal reagent solution with a second metal reagent solution; allowing a second segment of a 1D nanostructure to grow frommore » the first segment until a desired length is reached, wherein a segmented 1D nanostructure is produced.« less

Variation in the structure and optical properties of gamma-irradiated Vanadyl 2,3-naphthalocyanine (VONc) nanostructure films

NASA Astrophysics Data System (ADS)

Darwish, A. A. A.; Issa, Shams A. M.

2018-07-01

Naphthalocyanines have an important optical and electrical property, made it eligible to be a key utilitarian materials for a couple of special applications. Therefore, this study focused on the influence of gamma rays irradiation on the structure and optical properties of Vanadyl 2,3-naphthalocyanine (VONc) films. The VONc films have been prepared using the thermal evaporating technique. The investigated films were irradiated with gamma-rays 20, 40 and 60 kGy doses. X-ray diffraction exhibited that the as-deposited VONc films have nanostructure nature, which changed to the amorphous structure with gamma-rays radiation dosage. The optical results indicate that the optical absorption mechanism complied with the indirect allowed transition. It was observed also, there were no prominent changes found in the energy gap values when VONc films were exposed to gamma radiation. However, the optical conductivity rises with additional amounts of gamma-ray dose. This behavior may be attributed to the addition of electrons which freed by the incident photon energy because of a few changes in the film structure caused by the gamma-ray radiation. These outcomes illustrated that VONc films own the characteristics to be utilized in the field of optoelectronic applications.

Low Temperature Annealed Zinc Oxide Nanostructured Thin Film-Based Transducers: Characterization for Sensing Applications

PubMed Central

Haarindraprasad, R.; Hashim, U.; Gopinath, Subash C. B.; Kashif, Mohd; Veeradasan, P.; Balakrishnan, S. R.; Foo, K. L.; Poopalan, P.

2015-01-01

The performance of sensing surfaces highly relies on nanostructures to enhance their sensitivity and specificity. Herein, nanostructured zinc oxide (ZnO) thin films of various thicknesses were coated on glass and p-type silicon substrates using a sol-gel spin-coating technique. The deposited films were characterized for morphological, structural, and optoelectronic properties by high-resolution measurements. X-ray diffraction analyses revealed that the deposited films have a c-axis orientation and display peaks that refer to ZnO, which exhibits a hexagonal structure with a preferable plane orientation (002). The thicknesses of ZnO thin films prepared using 1, 3, 5, and 7 cycles were measured to be 40, 60, 100, and 200 nm, respectively. The increment in grain size of the thin film from 21 to 52 nm was noticed, when its thickness was increased from 40 to 200 nm, whereas the band gap value decreased from 3.282 to 3.268 eV. Band gap value of ZnO thin film with thickness of 200 nm at pH ranging from 2 to 10 reduces from 3.263eV to 3.200 eV. Furthermore, to evaluate the transducing capacity of the ZnO nanostructure, the refractive index, optoelectric constant, and bulk modulus were analyzed and correlated. The highest thickness (200 nm) of ZnO film, embedded with an interdigitated electrode that behaves as a pH-sensing electrode, could sense pH variations in the range of 2-10. It showed a highly sensitive response of 444 μAmM-1cm-2 with a linear regression of R2 =0.9304. The measured sensitivity of the developed device for pH per unit is 3.72μA/pH. PMID:26167853

Nanostructured Origami (Trademark) 3D Fabrication and Self Assembly Process for Soldier Combat Systems

DTIC Science & Technology

2004-12-01

the Japanese art of “ origami ”) involves patterning adjacent 2D membranes that can be lifted off (using methods we have developed) of a silicon...innovative process holds immense potential for the Army’s Objective Force Warrior. Nanostructured Origami enables many practical and promising...Nanostructured Origami allows such devices to be formed from a single, micro/nanofabricated layer. In addition, nanoarchitecture can be added

One-dimensional ZnO nanostructures.

PubMed

Jayadevan, K P; Tseng, T Y

2012-06-01

The wide-gap semiconductor ZnO with nanostructures such as nanoparticle, nanorod, nanowire, nanobelt, nanotube has high potential for a variety of applications. This article reviews the fundamentals of one-dimensional ZnO nanostructures, including processing, structure, property, application and their processing-microstructure-property correlation. Various fabrication methods of the ZnO nanostructures including vapor-liquid-solid process, vapor-solid growth, solution growth, solvothermal growth, template-assisted growth and self-assembly are introduced. The characterization and properties of the ZnO nanostructures are described. The possible applications of these nanostructures are also discussed.

Contribution of tin in electrochemical properties of zinc antimonate nanostructures: An electrode material for supercapacitors

NASA Astrophysics Data System (ADS)

Balasubramaniam, M.; Balakumar, S.

2018-04-01

Tin (Sn) doped ZnSb2O6 nanostructures was synthesized by chemical precipitation method and was used as an electrode material for supercapacitors to explore its electrochemical stability and potentiality as energy storage materials. Their characteristic structural, morphological and compositional features were investigated through XRD, FESEM and XPS analysis. Results showed that the nanostructures have well ordered crystalline features with spherical particle morphology. As the size and morphology are the vital parameters in exhibiting better electrochemical properties, the prepared nanostructures exhibited a significant specific capacitance of 222 F/g at a current density of 0.5 A/g respectively. While charging and discharging for 1000 cycles, the capacitance retention was enhanced to 105.0% which depicts the stability and activeness of electrochemical sites present in the Sn doped ZnSb2O6 nanostructures even after cycling. Hence, the inclusion of Sn into ZnSb2O6 has contributed in improving the electrochemical properties thereby it represents itself as a potential electrode material for supercapacitors.

Synthesis, characterization and biological studies of copper oxide nanostructures

NASA Astrophysics Data System (ADS)

Jillani, Saquf; Jelani, Mohsan; Hassan, Najam Ul; Ahmad, Shahbaz; Hafeez, Muhammad

2018-04-01

The development of synthetic methods has been broadly accepted as an area of fundamental importance to the understanding and application of nanoscale materials. It allows the individual to modulate basic parameters such as morphology, particle size, size distributions, and composition. Several methods have been developed to synthesize CuO nanostructures with diverse morphologies, sizes, and dimensions using different chemical and physical based approaches. In this work, CuO nanostructures have been synthesized by aqueous precipitation method and simple chemical deposition method. The characterization of these products has been carried out by the x-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) and UV–vis spectroscopy. Biological activity such as antibacterial nature of synthesized CuO is also explored. XRD peaks analysis revealed the monoclinic crystalline phase of copper oxide nanostructures. While the rod-like and particle-like morphologies have been observed in SEM results. FTIR spectra have confirmed the formation of CuO nanoparticles by exhibiting its characteristic peaks corresponding to 494 cm‑1 and 604 cm‑1. The energy band gap of the as-prepared CuO nanostructures determined from UV–vis spectra is found to be 2.18 eV and 2.0 eV for precipitation and chemically deposited samples respectively. The antibacterial activity results described that the synthesized CuO nanoparticles showed better activity against Staphylococcus aureus. The investigated results suggested the synthesis of highly stable CuO nanoparticles with significant antibacterial activities.

Osteointegration of PLGA implants with nanostructured or microsized β-TCP particles in a minipig model.

PubMed

Kulkova, Julia; Moritz, Niko; Suokas, Esa O; Strandberg, Niko; Leino, Kari A; Laitio, Timo T; Aro, Hannu T

2014-12-01

Bioresorbable suture anchors and interference screws have certain benefits over equivalent titanium-alloy implants. However, there is a need for compositional improvement of currently used bioresorbable implants. We hypothesized that implants made of poly(l-lactide-co-glycolide) (PLGA) compounded with nanostructured particles of beta-tricalcium phosphate (β-TCP) would induce stronger osteointegration than implants made of PLGA compounded with microsized β-TCP particles. The experimental nanostructured self-reinforced PLGA (85L:15G)/β-TCP composite was made by high-energy ball-milling. Self-reinforced microsized PLGA (95L:5G)/β-TCP composite was prepared by melt-compounding. The composites were characterized by gas chromatography, Ubbelohde viscometry, scanning electron microscopy, laser diffractometry, and standard mechanical tests. Four groups of implants were prepared for the controlled laboratory study employing a minipig animal model. Implants in the first two groups were prepared from nanostructured and microsized PLGA/β-TCP composites respectively. Microroughened titanium-alloy (Ti6Al4V) implants served as positive intra-animal control, and pure PLGA implants as negative control. Cone-shaped implants were inserted in a random order unilaterally in the anterior cortex of the femoral shaft. Eight weeks after surgery, the mechanical strength of osteointegration of the implants was measured by a push-out test. The quality of new bone surrounding the implant was assessed by microcomputed tomography and histology. Implants made of nanostructured PLGA/β-TCP composite did not show improved mechanical osteointegration compared with the implants made of microsized PLGA/β-TCP composite. In the intra-animal comparison, the push-out force of two PLGA/β-TCP composites was 35-60% of that obtained with Ti6Al4V implants. The implant materials did not result in distinct differences in quality of new bone surrounding the implant. Copyright © 2014 Elsevier Ltd. All

Emerging advances in nanomedicine with engineered gold nanostructures.

PubMed

Webb, Joseph A; Bardhan, Rizia

2014-03-07

Gold nanostructures possess unique characteristics that enable their use as contrast agents, as therapeutic entities, and as scaffolds to adhere functional molecules, therapeutic cargo, and targeting ligands. Due to their ease of synthesis, straightforward surface functionalization, and non-toxicity, gold nanostructures have emerged as powerful nanoagents for cancer detection and treatment. This comprehensive review summarizes the progress made in nanomedicine with gold nanostructures (1) as probes for various bioimaging techniques including dark-field, one-photon and two-photon fluorescence, photothermal optical coherence tomography, photoacoustic tomography, positron emission tomography, and surface-enhanced Raman scattering based imaging, (2) as therapeutic components for photothermal therapy, gene and drug delivery, and radiofrequency ablation, and (3) as a theranostic platform to simultaneously achieve both cancer detection and treatment. Distinct from other published reviews, this article also discusses the recent advances of gold nanostructures as contrast agents and therapeutic actuators for inflammatory diseases including atherosclerotic plaque and arthritis. For each of the topics discussed above, the fundamental principles and progress made in the past five years are discussed. The review concludes with a detailed future outlook discussing the challenges in using gold nanostructures, cellular trafficking, and translational considerations that are imperative for rapid clinical viability of plasmonic nanostructures, as well as the significance of emerging technologies such as Fano resonant gold nanostructures in nanomedicine.

Emerging advances in nanomedicine with engineered gold nanostructures

NASA Astrophysics Data System (ADS)

Webb, Joseph A.; Bardhan, Rizia

2014-02-01

Gold nanostructures possess unique characteristics that enable their use as contrast agents, as therapeutic entities, and as scaffolds to adhere functional molecules, therapeutic cargo, and targeting ligands. Due to their ease of synthesis, straightforward surface functionalization, and non-toxicity, gold nanostructures have emerged as powerful nanoagents for cancer detection and treatment. This comprehensive review summarizes the progress made in nanomedicine with gold nanostructures (1) as probes for various bioimaging techniques including dark-field, one-photon and two-photon fluorescence, photothermal optical coherence tomography, photoacoustic tomography, positron emission tomography, and surface-enhanced Raman scattering based imaging, (2) as therapeutic components for photothermal therapy, gene and drug delivery, and radiofrequency ablation, and (3) as a theranostic platform to simultaneously achieve both cancer detection and treatment. Distinct from other published reviews, this article also discusses the recent advances of gold nanostructures as contrast agents and therapeutic actuators for inflammatory diseases including atherosclerotic plaque and arthritis. For each of the topics discussed above, the fundamental principles and progress made in the past five years are discussed. The review concludes with a detailed future outlook discussing the challenges in using gold nanostructures, cellular trafficking, and translational considerations that are imperative for rapid clinical viability of plasmonic nanostructures, as well as the significance of emerging technologies such as Fano resonant gold nanostructures in nanomedicine.

On the design and fabrication of nanostructures and devices

NASA Astrophysics Data System (ADS)

Wei, Wei

Nanotechnology is emerging into a new frontier in science and technology with potential impact on every aspect of human life. One of the major breakthroughs in today's nanotechnology is the discovery and preparation of new classes of nanomaterials and nanostructures. A large number of nanomaterials and nanostructures are synthesized and characterized with either new or profoundly enhanced properties or phenomena. However, there are several major challenges ahead need to be overcome before any substantial benefits can be brought to the market. One of the challenges that we need to address today is how to effectively integrate useful nanomaterials and nanostrucrures into functional devices and systems. Our mother nature gives us a classic example of how living organisms are built. Starting from a single cell, through its division and growth, it can self-assemble and become functional tissues and organs. Similar self-assemble approach has been adopted as a nano-fabrication technique to assemble nanomaterials and nanostructures into functional nanodevices. This technique has advantages of high precision and nanometer scale resolution. However, it requires a lot of effort to construct a single device and since the properties of individual nanostructures can be different, the fabricated devices may have different properties. In this dissertation, we design and fabricate nanostructures and devices using novel microfabrication techniques. In the first part of the dissertation, the design and fabrication of a variety of nanostructures, such as metal nanowires array, polymer nanowells, and nanostructured surfaces are discussed. In the second part, carbon nanotubes as a novel material has been explored as an example to demonstrate the integration of nanomaterials with novel microfabrication techniques to form a functional device. First, a resistive heating technique is developed to grow carbon nanotubes in localized regions, such as a nichrome heating coil. Then, MEMS micro

Effect of Surfactant on the Morphology of ZnO/Al:ZnO Nanostructures and Their Ethanol Sensing Applications at Room Temperature

NASA Astrophysics Data System (ADS)

Chitra, M.; Uthayarani, K.; Rajasekaran, N.; Neelakandeswari, N.; Girija, E. K.; Padiyan, D. Pathinettam

2016-11-01

Zinc oxide (ZnO) and aluminum (Al) doped ZnO nanostructures with and without surfactant have been successfully prepared via sol-gel route. The effect of the surfactant glyoxalic acid and various concentration of Al on the structural property of ZnO was analyzed by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The morphology of the samples was recorded using field emission scanning electron microscopy. The uniform distribution of ZnO nanostructures with hexagonal facets is facilitated by the surfactant and the grain growth is further inhibited by the increase in concentration of Al. The ethanol (0-300ppm) sensing characteristics of the as-prepared samples were systematically investigated at room temperature. Surfactant-assisted ZnO/Al:ZnO nanostructures show higher sensitivity of 94% at room temperature than ZnO/Al:ZnO nanostructures without surfactant. Faster response at 68s and recovery at 50s is also achieved by the samples. The surfactant-assisted ZnO nanostructures exhibit sharp selective detection towards ethanol when compared to the samples without surfactant. The enhanced ethanol sensing property may be ascribed to the larger surface area which is due to uniform and smaller crystallite size of the surfactant-assisted sample.

User-Friendly End Station at the ALS for Nanostructure Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

F. J. Himpsel; P. Alivisatos; T. Callcott

2006-07-05

This is a construction project for an end station at the ALS, which is optimized for measuring NEXAFS of nanostructures with fluorescence detection. Compared to the usual electron yield detection, fluorescence is able to probe buried structures and is sensitive to dilute species, such as nanostructures supported on a substrate. Since the quantum yield for fluorescence is 10{sup -4}-10{sup -5} times smaller than for electrons in the soft x-ray regime, such an end station requires bright undulator beamlines at the ALS. In order to optimize the setup for a wide range of applications, two end stations were built: (1) Amore » simple, mobile chamber with efficient photon detection (>10{sup 4} times the solid angle collection of fluorescence spectrographs) and a built-in magnet for MCD measurements at EPU beamlines (Fig. 1 left). It allows rapid mapping the electronic states of nanostructures (nanocrystals, nanowires, tailored magnetic materials, buried interfaces, biologically-functionalized surfaces). It was used with BL 8.0 (linear polarized undulator) and BL 4.0 (variable polarization). (2) A sophisticated, stationary end station operating at Beamline 8.0 (Fig. 1 right). It contains an array of surface characterization instruments and a micro-focus capability for scanning across graded samples (wedges for thickness variation, stoichiometry gradients, and general variations of the sample preparation conditions for optimizing nanostructures).« less

Protein Bricks: 2D and 3D Bio-Nanostructures with Shape and Function on Demand.

PubMed

Jiang, Jianjuan; Zhang, Shaoqing; Qian, Zhigang; Qin, Nan; Song, Wenwen; Sun, Long; Zhou, Zhitao; Shi, Zhifeng; Chen, Liang; Li, Xinxin; Mao, Ying; Kaplan, David L; Gilbert Corder, Stephanie N; Chen, Xinzhong; Liu, Mengkun; Omenetto, Fiorenzo G; Xia, Xiaoxia; Tao, Tiger H

2018-05-01

Precise patterning of polymer-based biomaterials for functional bio-nanostructures has extensive applications including biosensing, tissue engineering, and regenerative medicine. Remarkable progress is made in both top-down (based on lithographic methods) and bottom-up (via self-assembly) approaches with natural and synthetic biopolymers. However, most methods only yield 2D and pseudo-3D structures with restricted geometries and functionalities. Here, it is reported that precise nanostructuring on genetically engineered spider silk by accurately directing ion and electron beam interactions with the protein's matrix at the nanoscale to create well-defined 2D bionanopatterns and further assemble 3D bionanoarchitectures with shape and function on demand, termed "Protein Bricks." The added control over protein sequence and molecular weight of recombinant spider silk via genetic engineering provides unprecedented lithographic resolution (approaching the molecular limit), sharpness, and biological functions compared to natural proteins. This approach provides a facile method for patterning and immobilizing functional molecules within nanoscopic, hierarchical protein structures, which sheds light on a wide range of biomedical applications such as structure-enhanced fluorescence and biomimetic microenvironments for controlling cell fate. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Epitaxial growth of hybrid nanostructures

NASA Astrophysics Data System (ADS)

Tan, Chaoliang; Chen, Junze; Wu, Xue-Jun; Zhang, Hua

2018-02-01

Hybrid nanostructures are a class of materials that are typically composed of two or more different components, in which each component has at least one dimension on the nanoscale. The rational design and controlled synthesis of hybrid nanostructures are of great importance in enabling the fine tuning of their properties and functions. Epitaxial growth is a promising approach to the controlled synthesis of hybrid nanostructures with desired structures, crystal phases, exposed facets and/or interfaces. This Review provides a critical summary of the state of the art in the field of epitaxial growth of hybrid nanostructures. We discuss the historical development, architectures and compositions, epitaxy methods, characterization techniques and advantages of epitaxial hybrid nanostructures. Finally, we provide insight into future research directions in this area, which include the epitaxial growth of hybrid nanostructures from a wider range of materials, the study of the underlying mechanism and determining the role of epitaxial growth in influencing the properties and application performance of hybrid nanostructures.

Acoustoelectric Effect on the Responses of SAW Sensors Coated with Electrospun ZnO Nanostructured Thin Film

PubMed Central

Tasaltin, Cihat; Ebeoglu, Mehmet Ali; Ozturk, Zafer Ziya

2012-01-01

In this study, zinc oxide (ZnO) was a very good candidate for improving the sensitivity of gas sensor technology. The preparation of an electrospun ZnO nanostructured thin film on a 433 MHz Rayleigh wave based Surface Acoustic Wave (SAW) sensor and the investigation of the acoustoelectric effect on the responses of the SAW sensor are reported. We prepared an electrospun ZnO nanostructured thin film on the SAW devices by using an electrospray technique. To investigate the dependency of the sensor response on the structure and the number of the ZnO nanoparticles, SAW sensors were prepared with different coating loads. The coating frequency shifts were adjusted to fall between 100 kHz and 2.4 MHz. The sensor measurements were performed against VOCs such as acetone, trichloroethylene, chloroform, ethanol, n-propanol and methanol vapor. The sensor responses of n-propanol have opposite characteristics to the other VOCs, and we attributed these characteristics to the elastic effect/acoustoelectric effect.

Dendrimer-magnetic nanostructure: a Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Jabar, A.; Masrour, R.

2017-11-01

In this paper, the magnetic properties of ternary mixed spins (σ,S,q) Ising model on a dendrimer nanostructure are studied using Monte Carlo simulations. The ground state phase diagrams of dendrimer nanostructure with ternary mixed spins σ = 1/2, S = 1 and q = 3/2 Ising model are found. The variation of the thermal total and partial magnetizations with the different exchange interactions, the external magnetic fields and the crystal fields have been also studied. The reduced critical temperatures have been deduced. The magnetic hysteresis cycles have been discussed. In particular, the corresponding magnetic coercive filed values have been deduced. The multiples hysteresis cycles are found. The dendrimer nanostructure has several applications in the medicine.