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1.
Cottineau T Albrecht A Janowska I Macher N Bégin D Ledoux MJ Pronkin S Savinova E Keller N Keller V Pham-Huu C 《Chemical communications (Cambridge, England)》2012,48(9):1224-1226
Novel transparent 1D-TiO(2)/few-layer graphene electrodes are realised by the anodic growth of vertically aligned TiO(2) nano-tubes on a few-layer graphene film coated on a glass substrate. 相似文献
2.
Eres G Kinkhabwala AA Cui H Geohegan DB Puretzky AA Lowndes DH 《The journal of physical chemistry. B》2005,109(35):16684-16694
The main obstacle to widespread application of single-wall carbon nanotubes is the lack of reproducible synthesis methods of pure material. We describe a new growth method for single-wall carbon nanotubes that uses molecular beams of precursor gases that impinge on a heated substrate coated with a catalyst thin film. In this growth environment the gas and the substrate temperature are decoupled and carbon nanotube growth occurs by surface reactions without contribution from homogeneous gas-phase reactions. This controlled reaction environment revealed that SWCNT growth is a complex multicomponent reaction in which not just C, but also H, and O play a critical role. These experiments identified acetylene as a prolific direct building block for carbon network formation that is an order of magnitude more efficient than other small-molecule precursors. The molecular jet experiments show that with optimal catalyst particle size the incidence rate of acetylene molecules plays a critical role in the formation of single-wall carbon nanotubes and dense vertically aligned arrays in which they are the dominant component. The threshold for vertically aligned growth, the growth rate, the diameter, and the number of walls of the carbon nanotubes are systematically correlated with the acetylene incidence rate and the substrate temperature. 相似文献
3.
Conducting Polyaniline Nanowire Arrays Modified Electrode for High Performance Supercapacitor and Enhanced Catalysis of Nitrite Reduction
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Vertically aligned conducting polymer nanowire arrays had great potential applications in supercapacitor electrode material and exhibited enhanced electrocatalytic behavior towards the reduction of nitrite. In this paper, a facial template‐free approach to synthesize large arrays of vertically aligned polyaniline (PANI) nanowires on electrochemically pretreated glassy carbon electrodes was reported by using a galvanostatic current method. The as‐prepared large arrays of PANI nanowires had very narrow diameters and were oriented perpendicular to the substrate, which was a benefit to the ion diffusion when being used as the supercapacitor electrode. The highest specific capacitance of PANI nanowire arrays was measured and kept high at a large charge‐discharge current density. Furthermore, it also can detect nitrite with ultrahigh sensitivity of 62.99 µA mM?1 cm?2 and a remarkable fast response time of less 1 s. The results indicated that the vertically aligned PANI nanowires could dramatically enhance the electrochemical performance. 相似文献
4.
A facile strategy for preparing vertically aligned polypyrrole (PPy) nanoarrays with precisely controlled density and quantity is presented. The method involves two steps: (1) the fabrication of the patterned substrate via electron beam lithography and (2) the controlled growth of PPy nanowires via electrochemical polymerization on the patterned substrate. The electrical property of a single PPy nanowire is investigated via in situ conducting probe atomic force microscopy. 相似文献
5.
A Versatile Anisometric Metallic Supercrystal with Controllable Orientation on a Chip as a Stable and Reliable Label‐Free Biosensor
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Li Qiu Wei Qiang Wang Dr. Nan Nan Zhang Hao Wei Jia Prof. Dr. Jin Wang Prof. Dr. Hong Hua Ge 《化学:亚洲杂志》2016,11(2):256-264
Based on anisometric noble‐metal nanocrystals, a universal fabrication protocol for preparing 3D supercrystals with controlled orientation on a chip has been developed. A comparison of the surface‐enhanced Raman scattering (SERS) behavior of 3D nanorod supercrystals aligned vertically and parallel to the chip indicates that the SERS‐enhancing ability and reproducibility of the former is superior to the latter. The 3D nanorod supercrystals aligned vertically to the chip have been utilized as highly sensitive SERS substrates for the label‐free discrimination of Gram‐positive and ‐negative bacteria. Furthermore, to strengthen the stability of the supercrystal substrate for assays of bacteria in biosamples, a coating of the antibiotic vancomycin can dramatically increase adhesion of bacteria on a nanointerface and simultaneously improve the SERS response of bacteria to achieve a layer‐by‐layer assembled, stable, and reliable biosensor for bacteria. 相似文献
6.
Ji-cheng Zhang Yong-jian Tang Yong Yi Min-jie Zhou Kang-fu Ma Wei-dong Wu Chao-yang Wang Yan Zhao Bing-chi Luo Zhuo Wang 《化学物理学报(中文版)》2015,28(5):617-622
Vertically aligned multi-walled carbon nanotube arrays grown on quartz substrate are obtained by co-pyrolysis of xylene and ferrocene at 850 oC in a tube furnace. Raman spectroscopy and high resolution transmission electron microscopy measurements show that the single-walled carbon nanotubes are only present on top of vertically aligned multi-walled carbon nanotube arrays. It has been revealed that isolated single-walled carbon nanotubes are only present in those floating catalyst generated materials. It thus suggests that the single-walled carbon nanotubes here are also generated by floating catalyst. Vertically alignedcarbon nanotube arrays on the quartz substrate have shown good orientation and good graphitization. Meanwhile, to investigate the growth mechanism, two bi-layers carbon nan-otube films with di erent thickness have been synthesized and analyzed by Raman spectroscopy. The results show that the two-layer vertically aligned carbon nanotube films grow “bottom-up”. There are distinguished Raman scattering signals for the second layer itself, surface of the first layer, interface between the first and second layer, side wall and bottom surface. It indicates that the obtained carbon nanotubes follow the base-growth mechanism, and the single-walled carbon nanotubes grow from their base at the growth beginning when iron catalyst particles have small size. Those carbon nanotubes with few walls (typically <5 walls) have similar properties, which also agree with the base-growth mechanism. 相似文献
7.
《Chemical physics letters》2003,367(1-2):109-115
Metal-catalysed reactions between atomic H and C nanopowders in a modified CVD reactor are used to generate ordered arrays of aligned nanotubes. The technique allows to produce either deposits consisting of aligned bundles of nanotubes laying along the substrate or dense arrays of nanotubes oriented at variable angles with respect to the substrate surface. Moreover, controlled growth of densely packed nanotube arrays can be obtained at given locations of substrates by means of a process sequence which exposes patterned layers of thermally grown SiO2 onto Si(1 0 0) wafers to the reactant flows. This procedure has been successfully used to realize specific architectures, such as the selected-area growth of rather long (30–50 μm) and vertically aligned nanotubes bundles along the crossing lines of regularly shaped features. 相似文献
8.
Carbon nanotubes (CNTs) were prepared using different carrier gases, with ferrocene as the catalyst precusor and acetylene as the carbon source. The effects of ammonia and nitrogen as carrier gases on the structure and morphology of CNTs were investigated. Transmission electron microscope (TEM), high-resolution electron microscope (HRTEM), scanning electron microscope (SEM) and X-ray diffraction (XRD) were employed to characterize the products and the catalyst. Experiment results show that the CNTs grown in N2 gas exhibited cylindrical and tubular structure, while a bamboo-like structure was observed for the CNTs grown in NH3 gas. Moreover, vertically aligned CNTs were obtained on an A12O3 disk when NH3 was used as the carrier gas. The carrier gas also exerted influence on the shape of the catalyst. Based on the theory of active centers of catalysis and combined with the particle shape of the catalyst, a growth model for the vertically aligned CNTs on the substrate is given. 相似文献
9.
Iwasaki T Zhong G Aikawa T Yoshida T Kawarada H 《The journal of physical chemistry. B》2005,109(42):19556-19559
The root growth mode of extremely dense and vertically aligned single-walled carbon nanotubes (SWNTs) synthesized by microwave plasma chemical vapor deposition was clarified by a new method, marker growth, which does not require transmission electron microscopy. SWNT layers were grown intermittently on a substrate, and a line between the layers was used as a marker to identify the growth mode. Micro-Raman spectroscopy revealed that the SWNT layers have the same diameter distribution. 相似文献
10.
Lingchao Cao Yu Wang Dacheng Wei Lei Fu Ping'an Hu Hongliang Zhang Liping Huang Gui Yu 《Acta Physico》2008,24(6):951-954
A simple acid treatment method was applied to remove the catalyst impurities and other residues contaminated in the vertically aligned carbon nanotube arrays. We demonstrated that acid treatment was an efficient approach for aligned carbon nanotube purification. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the morphology of the aligned carbon nanotube arrays and to determine the efficiency of the purification. Using hydrochloric acid could efficiently eliminate catalyst impurities and retain the original structures of the aligned carbon nanotube arrays. The method provided a simple, economical, and effective way to purify the aligned carbon nanotubes, and it would promote the applications of vertically aligned carbon nanotube arrays in electronic field. 相似文献
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Shim TK Kim D Lee MH Rhee BK Cheong HM Kim HS Yoon KB 《The journal of physical chemistry. B》2006,110(34):16874-16878
A unidirectional ensemble of hemicyanine molecules was prepared by inserting the molecules into the vertical channels of a uniformly oriented zeolite (silicalite-1) film grown on a glass substrate. Fluorescence from this sample excited with light polarized along the vertical channel was 50 times larger than that excited with light polarized orthogonal to the vertical channel direction. These vertically aligned hemicyanine dyes were used to determine the ratio of the molecular hyperpolarizability components beta(zxx)/beta(zzz) of hemicyanine. 相似文献
14.
运用化学气相沉积法(CVD), 直接以Sn和S为原料分区加热蒸发, 通过控制温度分布、气压、载气流量和金属铅纳米颗粒分布等宏观实验条件, 成功制备大面积Sn2S3一维纳米结构阵列. 扫描电子显微镜(SEM)图片显示: Sn2S3一维纳米结构的横向尺度在100 nm左右, 长约几个微米. X射线衍射(XRD)谱显示: 所制备样品的晶体结构属于正交晶系, 沿[002]方向生长. 紫外-可见漫反射谱表明Sn2S3一维纳米结构是带隙为2.0 eV的直接带隙半导体. 讨论了温度分布和金属铅纳米颗粒对Sn2S3一维纳米结构生长的影响, 并指出其生长可能遵循气-固(V-S)生长机理. 相似文献
15.
A single-cell-gap transflective liquid crystal display with a vertically aligned cell using square ring electrode is demonstrated. The top substrate has a top planar common electrode, a square ring pixel electrode is coated on the bottom substrate, while a bumpy reflector is coated under the bottom substrate. In this device, the planar common electrode and square ring pixel electrode generate a strong longitudinal electric field in the transmissive region (T region) and a weak fringe field in the reflective region (R region). As result, the T and R regions accumulate the same optical phase retardation. The simulation results show that the display exhibits reasonably low operating voltage, high transmittance and well-matched voltage-dependent transmittance and reflectance curves. Besides, fabrication process of the transflective liquid crystal display is very simple. 相似文献
16.
《Electrochemistry communications》2007,9(7):1677-1683
The influence of both nanotube orientation and length on the electrochemical properties of electrodes modified with single-walled carbon nanotubes was investigated. Gold electrodes were modified with either randomly dispersed or vertically aligned nanotubes to which ferrocenemethylamine was attached. Electron transfer kinetics were found to depend strongly on the orientation of the nanotube, with electron transfer between the gold electrode and the ferrocene moiety being 40 times slower through randomly dispersed nanotubes than through vertically aligned nanotubes. The difference is hypothesized to be due to electron transfer being more direct through a single tube than that with electrodes modified with randomly dispersed nanotubes. With the vertically aligned nanotubes the rate constant for electron transfer varied inversely with the mean length of the nanotubes. The results indicate there is an advantage in using aligned carbon nanotube arrays over randomly dispersed nanotubes for achieving efficient electron transfer to bound redox active species such as in the case of bioelectronic or photovoltaic devices. 相似文献
17.
Location‐Controlled Growth of Vertically Aligned Si Nanowires using Au Nanodisks Patterned by KrF Stepper Lithography
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The location‐controlled epitaxial growth of vertically aligned Si nanowire (v‐SiNW) arrays over large surface area was investigated with Au nanodisks (AuNDs) patterned by KrF stepper lithography. There are two steps for synthesizing v‐SiNWs from an AuND pattern: annealing and growth. The annealing process induces the formation of a single Au nanoparticle (AuNP) from an AuND pattern, which consists of several cracked AuNPs. Here, the oxide layer between the AuNDs and Si substrate is necessary for impeding the diffusion of Si atoms into the AuNPs. However, the oxide layer must be removed for properly aligned epitaxial SiNW growth. These SiNW arrays in large area can contribute highly to improve a nanowire‐based engineering by controlling the location of SiNWs with consistent pitch. 相似文献
18.
Yun Y Shanov V Tu Y Subramaniam S Schulz MJ 《The journal of physical chemistry. B》2006,110(47):23920-23925
Highly aligned arrays of multiwalled carbon nanotube (MWCNT) on layered Si substrates have been synthesized by chemical vapor deposition (CVD). The effect of the substrate design and the process parameters on the growth mechanism were studied. Adding water vapor to the reaction gas mixture of hydrogen and ethylene enhanced the growth which led to synthesis of longer CNT arrays with high density. Environmental scanning electron microscopy (ESEM), energy-dispersive spectroscopy (EDS), and atomic force microscopy (AFM) were used to analyze the CNT morphology and composition. Quadrupole mass spectroscopy (QMS) provided in-situ information on the gas spices within the reaction zone. On the basis of results, we verified the top growth mechanism and evaluated the reason of decline and stoppage of the CNT growth after extended period of deposition. Multilayered Si substrates with a top film of Al2O3, having appropriate roughness, provide favorable conditions to form catalyst islands with uniform distribution and size. Using water-assisted CVD process and optimized substrate design, our group succeeded to grow vertically aligned, patterned MWCNT up to 4-mm long. The arrays were of high purity and weak adhesion which allowed to be peeled off easily from the substrate. 相似文献
19.
Vertically aligned perfectly hexagonal-shaped ZnO nanoprisms have been grown on a Si(100) substrate via a noncatalytic thermal evaporation process by using metallic zinc powder in the presence of oxygen gas. The as-grown nanoprisms consist of ultra smooth Zn-terminated (0001) facets bounded with the {0110} surfaces. The as-synthesized products are single-crystalline with the wurtzite hexagonal phase and grown along the [0001] direction, as confirmed from the detailed structural investigations. The presence of a sharp and strong nonpolar optical phonon high-E2 mode at 437 cm(-1) in the Raman scattering spectrum further confirms good crystallinity and wurtzite hexagonal phase for the as-grown products. The as-grown nanoprisms exhibit a strong near-band-edge emission with a very weak deep-level emission in the room-temperature and low-temperature photoluminescence measurements, confirming good optical properties for the deposited products. Moreover, systematic time-dependent experiments were also performed to determine the growth process of the grown vertically aligned nanoprisms. 相似文献
20.
D. A. L. Almeida E. F. Antunes V. Q. da Silva M. R. Baldan N. G. Ferreira 《Journal of Solid State Electrochemistry》2013,17(7):1977-1984
Composite electrodes of vertically aligned carbon nanotubes (VACNT) were synthesized on carbon fiber (CF) substrate by pyrolysis of camphor/ferrocene using a SiO2 interlayer as a barrier against metal diffusion into the substrate. Two treatments were used to remove iron from CF/VACNT structure: thermal annealing at high temperature under inert atmosphere and electrochemical oxidation in H2SO4 solution. The composites were characterized by scanning electron microscopy and Raman scattering spectroscopy. Besides, the electrochemical behavior of CF/VACNT was analyzed by cyclic voltammetry and charge/discharge tests. CF/VACNT composite submitted to the electrochemical oxidation showed the best electrochemical performance, with high specific capacitance, which makes it very attractive as electrode for supercapacitors. 相似文献