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Nanorods
Kinds of Nanorods Terms modified by Nanorods Selected AbstractsA One-Step Method for the Growth of Ga2O3 -Nanorod-Based White-Light-Emitting PhosphorsADVANCED MATERIALS, Issue 35 2009Sampathkumar Chrisolite Vanithakumari A one-step synthesis of Ga2O3 nanorods by heating molten gallium in ambient air at high temperatures is presented. The high-temperature synthesis creates oxygen vacancies and incorporates nitrogen from the environment. The oxygen vacancy in Ga2O3 is responsible for the emission in the blue,green region, while nitrogen in Ga2O3 is responsible for red emission. [source] Nanorod-Based Dye-Sensitized Solar Cells with Improved Charge Collection Efficiency,ADVANCED MATERIALS, Issue 1 2008H. Kang Dye-sensitized solar cells (DSSCs) comprising chemically synthesized nanorods and nanoparticles are investigated. In identical circumstances, except for the charge-collection efficiency, nanorod-based DSSCs show improved photovoltaic properties (6.2 % versus 4.3 % for NP-based DSSCs) owing to the characteristics of slightly enhanced electron transport and predominantly degraded charge recombination, compared with nanoparticle-based DSSC. [source] Template Deformation-Tailored ZnO Nanorod/Nanowire Arrays: Full Growth Control and Optimization of Field-EmissionADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Haibo Zeng Abstract Here, a facile and effective route toward full control of vertical ZnO nanorod (NR)/nanowire (NW) arrays in centimeter-scale areas and considerable improvement of field-emission (FE) performance is reported. Controlled deformation of colloidal crystal monolayer templates is introduced by heating near glass-transition temperature. The NR/NW density, uniformity, and tapering were all adjusted through selection of template size and deformation, and electrolyte composition. In line with the adjustments, the field-emission performance of the arrays is significantly improved. A low turn-on electric field of 1.8,V µm,1, a field-enhancement factor of up to 5,750, and an emitting current density of up to 2.5,mA cm,2 were obtained. These improved parameters would benefit their potential application in cold-cathode-based electronics. [source] Nanoparticle Arrays on Surfaces Fabricated Using Anodic Alumina Films as Templates,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2003M.S. Sander Abstract High density nanoparticle arrays on surfaces have been created using a template-assisted approach. Templates were produced by evaporating aluminum onto substrates and subsequently anodizing the aluminum to produce nanoporous alumina films. The resulting templates have a narrow distribution of pore sizes tunable from ,,25 to ,,70 nm. To demonstrate the flexibility of this approach for producing nanoparticle arrays on various substrates, templates have been fabricated on silicon oxide, silicon, and gold surfaces. In all cases, a final chemical etching step yielded pores that extended completely through the template to the underlying substrate. Because the templates remain in intimate contact with the substrate throughout processing, they may be used with either vacuum-based or wet chemical deposition methods to direct the deposition of nanoparticles onto the underlying substrates. Here we have produced gold nanodot arrays using evaporation and gold nanorod arrays by electrodeposition. In each case, the diameter and height of the nanoparticles can be controlled using the confining dimensions of the templates, resulting in high density (,,1010,cm,2) arrays of nanoparticles over large areas (>,1 cm2). [source] Mechanically Powered Transparent Flexible Charge-Generating Nanodevices with Piezoelectric ZnO NanorodsADVANCED MATERIALS, Issue 21 2009Min-Yeol Choi Transparent flexible charge-generating piezoelectric nanodevices are developed. The resulting integrated nanodevice generates a noticeable current when it is pushed by application of an external load. Piezoelectric ZnO nanorod-based nanodevices with embossed PdAu top electrodes produce the highest output current density of approximately 10 ,A cm,2 at a load of 0.9 kgf. [source] Plasmon Coupling in Dimers of Au Nanorods,ADVANCED MATERIALS, Issue 22 2008Padmanabhan Pramod The coupled plasmon absorption of Au nanorod dimers is investigated as a function of the orientation between the long-axes of the nanorod by linking them with rigid and flexible molecules. As the angle between the Au nanorods increases, the coupled plasmon band shifts to longer wavelength confirming the role of effective dipolar overlap. [source] Nanorod-Based Dye-Sensitized Solar Cells with Improved Charge Collection Efficiency,ADVANCED MATERIALS, Issue 1 2008H. Kang Dye-sensitized solar cells (DSSCs) comprising chemically synthesized nanorods and nanoparticles are investigated. In identical circumstances, except for the charge-collection efficiency, nanorod-based DSSCs show improved photovoltaic properties (6.2 % versus 4.3 % for NP-based DSSCs) owing to the characteristics of slightly enhanced electron transport and predominantly degraded charge recombination, compared with nanoparticle-based DSSC. [source] Low-Temperature Growth of Rutile Nanorod Thin Films and their Photon-Induced PropertyJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2008Jin-Ming Wu Thin films of well-crystallized pure rutile nanorods were deposited on Ti substrates through a simple solution approach at a low temperature of 353 K. Field emission scanning electron microscopic and atomic force microscopic investigations revealed topographies of both quasi-aligned and less-aligned nanorod arrays, depending on Ti grain facets. X-ray diffraction and Raman spectra analysis verified that the deposited nanorod thin film was phase-pure rutile. This rutile nanorod was identified to be single crystalline growing along the [001] direction by high-resolution transmission electron microscopy. UV-Vis diffuse reflectance spectra estimated a remarkable red shift in responsive light for the nanorods when compared with that of bulk rutile. Under illumination of artificial solar light, the ability of the rutile nanorod film to aid photodegradation of rhodamine B in water was argued to be superior to the rutile nanoparticles isolated from commercial Degussa P25, which was attributed to the unique rod-like nanostructure. [source] Orientation of Syndiotactic Polystyrene Crystallized in Cylindrical NanoporesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2009Hui Wu Abstract Syndiotactic polystyrene (sPS) nanorods with different diameters have been prepared by using anodic aluminum oxide templates, and the orientation of the sPS crystals in the nanorods has been investigated by FT-IR spectroscopy. It is found that the c axis of the ,, crystals preferentially oriented perpendicular to the axis of the nanorod, and the degree of orientation is lower as the diameter of the nanorod decreases. This unexpected result is attributed to nuclei formed at the surface of the nanopores and their subsequent growth, in addition to the preferential growth compatible with the pore direction by the nuclei formed in the bulk film and in the nanorods. [source] Synthesis and characterization of ,-Al2O3 nanorodsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2006W. F. Li Abstract One-dimensional nanorods of cubic aluminum oxide (,-Al2O3) have been synthesized by DC electric arc discharge of Fe and Al powders. It is seen that the diameters of the ,-Al2O3 nanorods are relatively uniform, ranging from 20 to 30 nm. On the basis of detailed transmission electron microscopic observation, it is proposed that the growth of a ,-Al2O3 nanorod follows the vapor,liquid,solid (VLS) process assisted by a two-dimensional vapor,solid (VS) nucleation and growth mechanism. The features of heavy twinning in the nanorod imply that twins might contribute to the growth of the nanorod and serve as the nucleus of the nanorod. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] FIB fabrication of ZnO nanotetrapod and cross-sensorPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2010Lee Chow Abstract This article presents the fabrication of zinc oxide (ZnO) nanotetrapod and cross-nanorods-based sensors. This low-dimensional device is made in a focused ion beam set-up by using nanodeposition for metal electrodes. The gas response of the sensor based on an individual zinc oxide nanotetrapod and on crossed ZnO nanorod for detection of ultraviolet (UV) light and hydrogen at room temperature is presented. It is shown that ZnO tetrapod has potential application as UV and as chemical sensor with multi-terminal construction. The chemisorbed gas molecules on the ZnO surface can extract or donate electrons to ZnO and this effect was used to monitor the electrical resistance values change of the tetrapod sensor. ZnO tetrapod sensor demonstrates sensitivity and selectivity in resistance upon exposure to UV light, H2, O2, NH3, CO, CO2, and LPG gas. The resistivity change is different for UV and for H2 gas sensing. The presented ZnO sensor proves to be promising for application in various processes. [source] Direct Oxidation of Benzene to Phenol by Dioxygen over Nano-vanadium OxideCHINESE JOURNAL OF CHEMISTRY, Issue 11 2009Xiaohan Gao Abstract Reducing regents, such as ascorbic acid, are needed for vanadium-containing catalysts to catalyze the direct oxidation of benzene to phenol by dioxygen. Quadrivalent vanadium species, reduced from quinquevalent vanadium species, can activate dioxygen to produce active oxygen species, which is important for the reaction. The key step is to prepare more V4+ -containing catalysts. Here, VOX -C16 -A was prepared in an acidic medium to produce more V4+ species. The results of XPS and XRD studies confirmed that the vanadium species in VOX -C16 -A was mainly V4+ ions. The results of XRD and electron diffraction patterns revealed that VOX -C16 -A consisted of tetragonal VO2 and monoclinic VO2. Morphology observations display that the VOX -C16 -A is made of nanorod. Investigations into the performances of the catalysts showed that VOX -C16 -A was reusable, producing a 1.9% conversion of benzene without reducing agent. [source] Synthesis and properties of ,-Fe2O3 nanorodsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2010R. Ramesh Abstract We report synthesis of ,-Fe2O3 (hematite) nanorods by reverse micelles method using cetyltrimethyl ammonium bromide (CTAB) as surfactant and calcined at 300 °C. The calcined ,-Fe2O3 nanorods were characterized by X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). The result showed that the ,-Fe2O3 nanorods were hexagonal structure. The nanorods have diameter of 30-50 nm and length of 120-150 nm. The weak ferromagnetic behavior was observed with saturation magnetization = 0.6 emu/g, coercive force = 25 Oe and remanant magnetization = 0.03 emu/g. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Epitaxial Sn1-xPbxS nanorods on iso-compositional thin filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2010K. Bente Abstract Based on SnS (Herzenbergite) , SnPbS2 (Teallite) mixed crystals with orthorhombic layer structures, thin films and lawns of Sn1-xPbxS nanorods were produced using hot wall vacuum deposition method (HWVD). The lawn was formed onto the surface of an underlying thin Sn1-xPbxS film which is build by differently oriented blocks. The density of rods arranged like a lawn depends on the metal ratio and substrate temperature. X-ray and TEM analysis of the epitaxial material showed preferential (001) orientation perpendicular to the surface of the glass substrate. The roughness of the films measured by atomic force microscopy was in the range of Rq = 49.5,86.3 nm depending on lead concentration The rods were about 500 nm high and 300 nm in diameter. As revealed by TEM-EDX experiments the droplet at the tip of rods consists of tin. Therefore it is assumed the rods grew via a self-consuming vapor,liquid,solid (VLS) mechanism. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation of shuttle-like Sb2S3 nanorod-bundles via a solvothermal approach under alkaline conditionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2010Ling Zhang Abstract Uniform shuttle-like Sb2S3 nanorod-bundles were synthesized via a polyvinylpyrrolidone (PVP) assisted solvothermal approach under alkaline condition, using antimony chloride (SbCl3) and thiourea (CH4N2S, Tu) as the starting materials in ethanol. The phase structure, composition and morphology of the product were characterized by means of X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). XRD and EDS results confirm that the synthesized Sb2S3 nanorod-bundles have an orthorhombic structure and an atomic ratio of 3:2 for S:Sb. TEM and HRTEM results show that the shuttle-like Sb2S3 bundles are composed of nanorods with a size distribution of 20-40 nm and growing along c-axis. Furthermore, experiments under different reaction conditions were carried out and the mechanism for the growth of nanorod-bundles was discussed (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Sonochemical synthesis and characterization of ZnO nanorod/Ag nanoparticle compositesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2009Fei Li Abstract A simple sonochemical route for the synthesis of Ag nanoparticles on ZnO nanorods is reported. Ultrasonic irradiation of a mixture of ZnO nanorods, Ag(NH3)2+, and formaldehyde in an aqueous medium yields ZnO nanorod/Ag nanoparticle composites. The powder X-ray diffraction of the ZnO/Ag composites shows additional diffraction peaks corresponding to the face-center-cubic structured Ag crystalline, apart from the signals from the ZnO nanorods. Scanning electron microscopy and transmission electron microscopy images of the ZnO/Ag composites reveal that the ZnO nanorods are coated with Ag nanoparticles with a mean size of several tens nanometer. The absorption band of ZnO/Ag composites is distinctly broadened and red-shifted, indicating the strong interfacial interaction between ZnO nanorods and Ag nanoparticles. This sonochemical method is simple, mild and readily scaled up, affording a simple way for synthesis of other composites. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Solvothermal production of CdS nanorods using polyvinylpyrrolidone as a templateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2009Titipun Thongtem Abstract CdS nanorods were solvothermally produced using Cd(NO3)2 and S powder in ethylenediamine containing different amounts of polyvinylpyrrolidone (PVP). The phase with hexagonal structure was detected using X-ray diffraction (XRD) and selected area electron diffraction (SAED). Their SAED patterns were in accordance with those of the simulations. Scanning and transmission electron microscopies (SEM and TEM) revealed the presence of CdS nanorods with their lengths influenced by different amounts of PVP. The nanorods were also characterized using high resolution TEM (HRTEM). They grew in the [001] direction normal to the (002) parallel crystallographic planes composing the nanorods. Raman spectra showed the 1LO (first harmonic) and 2LO (second harmonic) modes at the same wavenumbers although the products were produced under different conditions. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low temperature hydrothermal growth and optical properties of ZnO nanorodsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2009J. H. Yang Abstract Well-faceted hexagonal ZnO nanorods have been synthesized by a simple hydrothermal method at relative low temperature (90°C) without any catalysts or templates. Zinc oxide (ZnO) nanorods were grown in an aqueous solution that contained Zinc chloride (ZnCl2, Aldrich, purity 98%) and ammonia (25%). Most of the ZnO nanorods show the perfect hexagonal cross section and well-faceted top and side surfaces. The diameter of ZnO nanorods decreased with the reaction time prolonging. The samples have been characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurement. XRD pattern confirmed that the as-prepared ZnO was the single-phase wurtzite structure formation. SEM results showed that the samples were rod textures. The surface-related optical properties have been investigated by photoluminescence (PL) spectrum and Raman spectrum. Photoluminescence measurements showed each spectrum consists of a weak band ultraviolet (UV) band and a relatively broad visible light emission peak for the samples grown at different time. It has been found that the green emission in Raman measurement may be related to surface states. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystalline bismuth oxide nanorods fabricated on Pt-coated substrates using a trimethylbismuth and oxygen mixtureCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2008Hyoun Woo Kim Abstract The current work reports the fabrication of crystalline Bi2O3 nanorods on Pt-coated Si substrates using trimethylbismuth and O2 as the bismuth and the oxygen sources, respectively, in the metalorganic chemical vapor deposition process. Their microstructures were characterized by scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The obtained nanorods were crystalline, with their diameters in the range of 20,200 nm. The absence of tip-nanoparticle and the presence of predeposited Bi2O3 layer indicated that the growth was dominated by a vapor-solid process. The photoluminescence measurements of the Bi2O3 nanorods at room temperature exhibited an emission band peaked at around 422 nm. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Direct Electron Transfer and Electrocatalysis of Hemoglobin on Chitosan-TiO2 Nanorods-Glass Carbon ElectrodeELECTROANALYSIS, Issue 20 2008Xiaoling Xiao Abstract The direct electron transfer between hemoglobin (Hb) and the glassy carbon electrode (GC) can be readily achieved via a high biocompatible composite system based on biopolymer chitosan (CHT) and TiO2 nanorods (TiO2 -NRs). TiO2 -NRs greatly promote the electron transfer between Hb and GC, which contribute to the higher redox peaks. UV-vis spectra result indicated the Hb entrapped in the composite film well keep its native structure. The immobilized Hb remains its bioelectrocatalytical activity to the reduction of H2O2 with a lower detection limit. A novel, sensitive, reproducible and stable electrochemical biosensing platform of H2O2 based on Hb-TiO2 -CHT electrode is explored. [source] Synthesis and Characterization of Colloidal Core,Shell Semiconductor NanowiresEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2010Zhen Li Abstract CdSe colloidal nanowires, generated from solution-liquid-solid approach, have been coated with CdS rods (or ribbons) by using cadmium hexadecyl xanthate (Cd-HDX) as a single source precursor. The use of different solvents and ligands causes pronounced effects on the morphology of the nanowires. The coating process includes nucleation and growth of CdS nanorods onto the core CdSe nanowires, followed by ripening of the CdS nanorods to produce the desired core-shell nanowire structure. [source] Synthesis of Zinc Glycerolate Microstacks from a ZnO Nanorod Sacrificial TemplateEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2009Róbert Rémiás Abstract We synthesized zinc glycerolate (ZnGly) microstacks bytreating ZnO with glycerol at 100 °C under reflux. We observed that the morphology of the ZnO source has a pronounced effect on the appearance of the ZnGly product. In the absence of structure-directing effects the product ZnGly is obtained as a random heap of hexagonal prisms with an average diameter and thickness of ca. 2.5 ,m and ca. 350 nm, respectively. However, bundles of nanorod-shaped ZnO obtained by the thermal decomposition of zinc oxalate nanorods could readily be transformed into 2,4 ,m long zinc glycerolate microstacks in which 6,12 hexagonal prisms are aligned face-to-face. We present evidence that the ZnGly plates in the microstacks are bound together by forces strong enough to withstand mechanical deformation exercised by a contacting AFM tip. The ZnGly microstacks appear to emerge from the ZnO nanorod bundles in an approx. 1:1 ratio in the reactive template synthesis.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Ultrasound-Assisted Synthesis of CuO Nanorods in a Neat Room-Temperature Ionic LiquidEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2009Tarek Alammar Abstract CuO nanorods were prepared via ultrasound-assisted synthesis in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] as a reaction medium. The structure and morphology of CuO nanorods were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), vibrational and UV/Vis absorption spectroscopy. The synthesized CuO nanocrystals are of rod like shape with lengths from 30 to 100 nm and diameters of about 10 nm. Quantum size effects were observed as the bandgap of the CuO nanorods was determined to 2.41 eV from UV/Vis absorption measurements, which is significantly larger than the bulk value. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] The Oriented Self-Assembly of Magnetic Fe3O4 Nanoparticles into Monodisperse Microspheres and Their Use as Substrates in the Formation of Fe3O4 NanorodsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2008Guangcheng Xi Abstract We describe a facile solvothermal route for the large-scale preparation of ferromagnetic Fe3O4 sub-micrometer spheres and nanorods by using FeCl3 as the iron source, oleic acid as the surfactant, and ethylene glycol as the reducing agent and solvent. The as-synthesized Fe3O4 microspheres are composed of a mess of Fe3O4 nanoparticles with a size of 10 nm and have nearly monodisperse diameters that can be controlled in the range 100,410 nm. HRTEM images and SAED patterns show that these microspheres present a "single-crystalline" nature, which can be attributed to the highly oriented assembly of the small Fe3O4 nanoparticles. Interestingly, by using the pre-synthesized Fe3O4 microspheres as the growth substrate, single-crystalline Fe3O4 nanorods can be formed on the surfaces of the microspheres. These nanorods are about 7,20 nm in diameter and 120,400 nm in length, and have smooth surfaces. The formation mechanisms of the Fe3O4 microspheres and nanorods have been investigated and discussed. Furthermore, the magnetic properties of the as-synthesized microspheres and nanorods have also been investigated and the magnetization saturation values are 74.6 and 92.3 emu/g, respectively.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Size- and Shape-Controlled Synthesis and Assembly of a Silver Nanocomplex in UV-Irradiated TSA SolutionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2006Liangbao Yang Abstract In this paper we describe the size-controlled synthesis ofa silver nanocomplex based on the reduction of silvernitrate (AgNO3) by UV-irradiated tungstosilicate acid [H4(SiW12O40), TSA] solution. This method allows the synthesis of ellipsoidal particles with an average size that is tunable between 2.4 and 84 nm by varying the molar ratio of silver nitrate to TSA, the pH of the reaction solution, and the reaction temperature. Silver nanorods can be formed from the ellipsoidal nanoparticles by controlling the aging time. The formation mechanism of these nanorods is also discussed. The nanoparticles are characterized by UV/Vis spectroscopy, FTIR spectroscopy, XRD analysis, XPS, electron diffraction (ED), TEM, and with a Zetasizer instrument. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Comparative Sol,Hydro(Solvo)thermal Synthesis of TiO2 NanocrystalsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2006Xianfeng Yang Abstract Three small inorganic compounds [acetic acid (CH3COOH), nitric acid (HNO3), and hydrochloric acid (HCl)] andfive small organic compounds [n -butyl alcohol (CH3CH2CH2CH2OH), 1,2-propanediol (CH2OHCHOHCH3), propane-1,3-dicarboxylic acid (HOOCCH2COOH), butane-1,4-dicarboxylic acid (HOOCCH2CH2COOH), and ethylenediamine (H2NCH2CH2NH2)] with different donors (Cl,, NO3,, OH, COO,, and NH2) are used respectively and comparatively in different reaction media for tailoring the sol,hydrothermal synthesis of TiO2 nanocrystals at a specific reaction temperature and/or for different reaction times. Both anatase and rutile with a variety of nanostructures such as nanocubes, nanorods, nanoneedles, and their self-assembled nanospheres are selectively grown. Well-defined and crystalline anatase nanocrystals with a narrow size distribution are prepared in the presence of n -butyl alcohol. With the use of HCl, nanoneedles and their assembled nanospheres of phase-pure rutile are obtained under much less drastic conditions, even at 100 °C and for only two hours. The effects of the reaction media, synthesis temperatures, and aging times on the structures and shapes of the products are investigated in detail by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Hierarchical ZnS-In2S3 -CuS Nanospheres with Nanoporous Structure: Facile Synthesis, Growth Mechanism, and Excellent Photocatalytic ActivityADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Yingxuan Li Abstract Without using any templates or surfactants, hierarchical ZnS-In2S3 -CuS nanospheres with nanoporous structure are successfully synthesized via a simple and convenient process. The nanospheres are aggregations of densely packed nanoparticles and nanorods. Different to the oriented attachment (OA) mechanism reported in the literature, the formation of these nanorods is believed to follow a lateral OA mechanism (nanoparticles attach along the direction perpendicular to the crystallographic axes with lateral planes as the juncture) based on the experimental data. This process could be a general phenomenon and would provide a new insight into the OA mechanism. A detailed time-resolved TEM kinetic study of the formation of the complex structure is shown. The dipole mechanism and electric field-induced growth are found to be responsible for the final architecture. Photocatalytic activities for water splitting are investigated under visible-light irradiation (, > 400 nm) and an especially high photocatalytic activity (apparent yield of 22.6% at 420 nm) is achieved by unloaded ZnIn0.25Cu0.02S1.395 prepared at 180 °C for 18 h because of their high crystallinity, large pore volume, and the presence of nanorods with special microstructures. [source] Hydrothermal Growth: Polymer-Templated Hydrothermal Growth of Vertically Aligned Single-Crystal ZnO Nanorods and Morphological Transformations Using Structural Polarity (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Mater. Abstract Position-configurable, vertical, single-crystalline ZnO nanorod arrays are fabricated via a polymer-templated hydrothermal growth method at a low temperature of 93 °C. A sol-gel processed dense c -oriented ZnO seed layer film is employed to grow nanorods along the c -axis direction [0001] regardless of any substrate crystal mismatches. Here, one-beam laser-interference lithography is utilized to fabricate nanoscale holes over an entire 2-in. wafer during the preparation of the polymer template. As such, vertically aligned ZnO nanorods can be grown from the seed layer exposed at the bottom of each hole. Furthermore, morphological transformations of the ZnO nanorods into pencil-like, needle-like, tubular, tree-like, and spherical shapes are obtained by controlling the growth conditions and utilizing the structural polarity of the ZnO nanorods. [source] Polymer-Templated Hydrothermal Growth of Vertically Aligned Single-Crystal ZnO Nanorods and Morphological Transformations Using Structural PolarityADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Ki Seok Kim Abstract Position-configurable, vertical, single-crystalline ZnO nanorod arrays are fabricated via a polymer-templated hydrothermal growth method at a low temperature of 93 °C. A sol-gel processed dense c -oriented ZnO seed layer film is employed to grow nanorods along the c -axis direction [0001] regardless of any substrate crystal mismatches. Here, one-beam laser-interference lithography is utilized to fabricate nanoscale holes over an entire 2-in. wafer during the preparation of the polymer template. As such, vertically aligned ZnO nanorods can be grown from the seed layer exposed at the bottom of each hole. Furthermore, morphological transformations of the ZnO nanorods into pencil-like, needle-like, tubular, tree-like, and spherical shapes are obtained by controlling the growth conditions and utilizing the structural polarity of the ZnO nanorods. [source] The Effect of Nanoparticle Shape on the Photocarrier Dynamics and Photovoltaic Device Performance of Poly(3-hexylthiophene):CdSe Nanoparticle Bulk Heterojunction Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Smita Dayal Abstract The charge separation and transport dynamics in CdSe nanoparticle:poly(3-hexylthiophene) (P3HT) blends are reported as a function of the shape of the CdSe-nanoparticle electron acceptor (dot, rod, and tetrapod). For optimization of organic photovoltaic device performance it is crucial to understand the role of various nanostructures in the generation and transport of charge carriers. The sample processing conditions are carefully controlled to eliminate any processing-related effects on the carrier generation and on device performance with the aim of keeping the conjugated polymer phase constant and only varying the shape of the inorganic nanoparticle acceptor phase. The electrodeless, flash photolysis time-resolved microwave conductivity (FP-TRMC) technique is used and the results are compared to the efficiency of photovoltaic devices that incorporate the same active layer. It is observed that in nanorods and tetrapods blended with P3HT, the high aspect ratios provide a pathway for the electrons to move away from the dissociation site even in the absence of an applied electric field, resulting in enhanced carrier lifetimes that correlate to increased efficiencies in devices. The processing conditions that yield optimum performance in high aspect ratio CdSe nanoparticles blended with P3HT result in poorly performing quantum dot CdSe:P3HT devices, indicating that the latter devices are inherently limited by the absence of the dimensionality that allows for efficient, prolonged charge separation at the polymer:CdSe interface. [source] |