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1.
利用金属蒸发真空多弧离子源注入机, 将Au离子注入到高纯石英玻璃来制备镶嵌有Au 纳米颗粒的衬底材料, 随后将化学方法合成的CdTe量子点旋涂在玻璃衬底上制备了Au纳米颗粒和CdTe量子点复合体系. 通过对镶嵌有Au纳米颗粒的衬底进行热退火处理来控制Au纳米颗粒的生长和分布, 系统研究了Au纳米颗粒的局域表面等离子体共振对CdTe量子点光致发光性能的影响. 利用光学吸收谱、原子力显微镜、透射电子显微镜和光致发光谱对样品进行了表征和测试. 光致发光谱表明, Au纳米颗粒的局域表面等离子体对CdTe量子点的发光有增强效应也有猝灭效应. 深入分析了Au纳米颗粒和CdTe量子点之间的相互作用过程, 提出了关于Au-CdTe 纳米复合体系中CdTe 发光增强和猝灭的新机理. 该实验结果为利用金属纳米颗粒表面等离子体技术制备高发光性能的光电子器件提供了较好的参考. 相似文献
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采用纳米球刻蚀技术中漂移法在玻璃基片上制备较大 面积不同直径的聚苯乙烯小球掩模板, 采用磁控溅射技术在掩模板上沉积不同厚度的金薄膜, 去除聚苯乙烯小球后, 通过扫描电子显微镜观察到周期排列的三角状金纳米颗粒点阵. 通过紫外-可见分光光度计测试所制备样品的光吸收特性, 发现表面等离子体共振峰随粒径增大发生红移, 随金纳米颗粒高度增加发生蓝移. 基于Mie理论, 利用Matlab软件编程对不同粒径的金阵列光吸收特性进行理论模拟, 并与实验结果进行对比.
关键词:
纳米球刻蚀
金纳米颗粒阵列
表面等离子体共振 相似文献
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采用加热分解油酸铁法制备了Fe3O4磁性纳米颗粒,并用有机模板和反相微乳液相结合的方法将磁性纳米颗粒包裹在多孔二氧化硅中.用红外光谱(FTIR)研究了不同的处理方式对油酸铁表面官能团的影响及油酸的反应浓度和加热分解油酸铁的过程中升温速率对Fe3O4纳米颗粒的影响.结果表明,用乙醇和丙酮处理后的固态蜡状油酸铁表面的油酸基团会受到损害,将不利于加热分解时形成单分散性的Fe3O4纳
关键词:
3O4纳米颗粒')" href="#">Fe3O4纳米颗粒
2包裹')" href="#">多孔SiO2包裹
反相微乳液法
油酸铁 相似文献
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采用离子交换结合热处理的方法在碱石灰玻璃表面制备了银纳米颗粒。通过紫外-可见分光光度计、X射线衍射仪、扫描电子显微镜对样品进行了表征。结果表明:热处理时,银离子在玻璃表面成核并生长成近似长方形的纳米颗粒。吸收光谱在416nm附近出现明显的银纳米颗粒表面等离子体共振吸收特征峰。 相似文献
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利用溶液共沉淀法制备了纳米氧化锌和三氧化二铁的非常均匀的混合物。通过常规的高温焙烧法和冲击波压缩方法分别合成了铁酸锌。这两种铁酸锌对硫化氢气体的光催化脱氢表现出显著不同的催化活性。试验表明:高温焙烧法合成的铁酸锌是一种颗粒度为几十纳米的结晶完整的化合物;而冲击波合成的铁酸锌是一种颗粒度为几个纳米的非化学计量比化合物,它的光催化活性随着冲击波合成压力的增高而迅速提高。在37 GPa时,冲击波合成的铁酸锌对H2S脱氢的光催化活性要比高温焙烧法制备的铁酸锌高出3倍以上。利用粉末X光衍射,透射电镜及电子衍射,Mossbauer谱等分析手段对这两种铁酸锌的晶格结构、细观特征及磁特性进行了表征。 相似文献
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用等离子体增强化学气相沉积法在低温(低于50℃)衬底上沉积Si-SiOx和Si-SiNx复合薄膜,可得到平均颗粒尺寸小至3nm的高密度(最高可达4.0×1012cm-2)纳米硅复合薄膜.500℃快速退火后,这种复 合薄膜显现出优异的可见光全波段光致发光特性.通过比较相同条件下所制备的纳米Si-SiOx和Si-SiNx复合薄膜的光致发光效率,发现纳米Si-SiNx具有更为优异 的光致发光效率,这一点在可见光短波区表现得尤为显著.
关键词:
等离子体增强化学气相沉积
冷衬底
硅纳米颗粒
光致发光 相似文献
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Dong Xi XiaoPing Luo QiangHua Lu KaiLun Yao ZuLi Liu Qin Ning 《Journal of nanoparticle research》2008,10(3):393-400
Gold-coated iron oxide nanoparticle Hepatitis B virus (HBV) DNA probes were prepared, and their application for HBV DNA measurement
was studied. Gold-coated iron oxide nanoparticles were prepared by the citrate reduction of tetra-chloroauric acid in the
presence of iron oxide nanoparticles which were added as seeds. With a fluorescence-based method, the maximal surface coverage
of hexaethiol 30-mer oligonucleotides and the maximal percentage of hybridization strands on gold-coated iron oxide nanoparticles
were (120 ± 8) oligonucleotides per nanoparticle, and (14 ± 2%), respectively, which were comparable with those of (132 ± 10)
and (22 ± 3%) in Au nanoparticle groups. Large network aggregates were formed when gold-coated iron oxide nanoparticle HBV
DNA gene probe was applied to detect HBV DNA molecules as evidenced by transmission electron microscopy and the high specificity
was verified by blot hybridization. Our results further suggested that detecting DNA with iron oxide nanoparticles and magnetic
separator was feasible and might be an alternative effective method. 相似文献
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Ilker Dincer Onur Tozkoparan Sergey V. German Alexey V. Markin Oguz Yildirim Gennady B. Khomutov Dmitry A. Gorin Sergey B. Venig Yalcin Elerman 《Journal of magnetism and magnetic materials》2012
Aqueous colloidal suspension of iron oxide nanoparticles has been synthesized. Z-potential of iron oxide nanoparticles stabilized by citric acid was −35±3 mV. Iron oxide nanoparticles have been characterized by the light scattering method and transmission electron microscopy. The polyelectrolyte/iron oxide nanoparticle thin films with different numbers of iron oxide nanoparticle layers have been prepared on the surface of silicon substrates via the layer-by-layer assembly technique. The physical properties and chemical composition of nanocomposite thin films have been studied by atomic force microscopy, magnetic force microscopy, magnetization measurements, Raman spectroscopy. Using the analysis of experimental data it was established, that the magnetic properties of nanocomposite films depended on the number of iron oxide nanoparticle layers, the size of iron oxide nanoparticle aggregates, the distance between aggregates, and the chemical composition of iron oxide nanoparticles embedded into the nanocomposite films. The magnetic permeability of nanocomposite coatings has been calculated. The magnetic permeability values depend on the number of iron oxide nanoparticle layers in nanocomposite film. 相似文献
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Hayden Carlton Kathryn Krycka Markus Bleuel David Huitink 《Particle & Particle Systems Characterization》2020,37(1):1900358
The study and fundamental understanding of magnetic nanoparticle induction heating remains critical for the advancement of magnetic hyperthermia technologies. Complete characterization of not only the nanoparticles themselves but their interparticle behavior in a sample matrix is necessary to accurately predict their heating response. Herein, an in situ method for measuring the extent of nanoparticle clustering during induction heating using small-angle and ultrasmall-angle neutron scattering facilities at the National Institute of Standards and Technology Center for Neutron Research is described and implemented by comparing two sets of iron oxide nanoparticles with differing structures and magnetic properties. By fitting the scattering profiles to a piecewise model covering a wide Q-range, the magnitude of nanoparticle clustering during induction heating is quantified. Observations of the low-Q intensity before and after heating also allow for relative measurement of the cluster volume fraction during heating. The use of this method can prove to be advantageous in both developing more encompassing models to describe magnetic nanoparticle dynamics during heating as well as optimizing nanoparticle synthesis techniques to reduce aggregation during heating. 相似文献
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Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward
organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate
stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer
is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type
and iron precursor (FeSO4·7H2O or FeCl3), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in
their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences
caused by the three stabilizers. A range of stabilizer-to-iron (0.05–0.9) and borohydride-to-iron (0.5–8) molar ratios were
tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous
sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested
resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles,
and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle
size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method,
was minimally successful in several different organic solvents. 相似文献
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Ali Nakhaei Pour Mohammad Reza Housaindokht Alireza Behroozsarand Mohammad Ali Khodagholi 《Applied Physics A: Materials Science & Processing》2014,116(2):789-797
The kinetic parameters of the Fischer–Tropsch synthesis (FTS) on iron catalyst are analyzed by size-dependent thermodynamic method. A Langmuir–Hinshelwood kinetic equation is considered for evaluation of catalytic activity of lanthanum promoted iron catalyst. A series of unsupported iron catalysts with different particle sizes were prepared via microemulsion method. The experimental results showed that catalyst activity pass from a maximum value by increasing the iron particle size. Also, data presented that iron particle size has considerable effects on adsorption parameters and FTS rates. The ratio of surface tension (σ) to nanoparticle radius (r) is important in FTS reaction on iron catalyst. Finally, the results showed that by increasing of iron particle size from 18 to 45 nm the activation energies of catalysts and heats of adsorption of catalysts as two main parameters of FTS reaction increased from 89 to 114 kJ/mol and from 51 to 71 kJ/mol, respectively. 相似文献
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The tubulization process of amorphous carbon nanopillars was observed in situ by transmis-sion electron microscopy. Amorphous carbon nanopillars were transformed into graphitic tubules by annealing at 650-900 degrees C in the presence of iron nanoparticles. A molten catalyst nanoparticle penetrated an amorphous carbon nanopillar, dissolving it, and leaving a graphite track behind. An iron nanoparticle moved with its shape changing like an earthworm. We concluded that the tubulization mechanism is a solid-(quasiliquid)-solid mechanism where the carbon phase transformation is a kind of liquid phase graphitization of amorphous carbon catalyzed by liquefied metal-carbon alloy nanoparticles. 相似文献
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Zhanhu Guo Di Zhang Suying Wei Zhe Wang Amar B. Karki Yuehao Li Paul Bernazzani David. P. Young J. A. Gomes David L. Cocke Thomas C. Ho 《Journal of nanoparticle research》2010,12(7):2415-2426
Iron oxide (α-phase) nanoparticles with coercivity larger than 300 Oe have been fabricated at a mild temperature by an environmentally benign method. The economic sodium chloride has been found to effectively serve as a solid spacer to disperse the iron precursor and to prevent the nanoparticles from agglomeration. Higher ratios of sodium chloride to iron nitrate result in smaller nanoparticles (19 nm for 20:1 and 14 nm for 50:1). The presence of polyvinyl alcohol (PVA) limits the particle growth (15 nm for 20:1 and 13 nm for 50:1) and favors nanoparticle dispersion in polymer matrices. Obvious physicochemical property changes have been observed with PVA attached to the nanoparticle surface. With PVA attached to the nanoparticle surface, the nanoparticles are found not only to increase the PVA cross-linking with an increase in melting temperature but also to enhance the thermal stability of the PVA. The nanoparticles are observed to be uniformly dispersed in the polymer matrix. Scanning electron microscopy (SEM) microstructure also shows an intermediate phase with a strong interaction between the nanoparticles and the polymer matrices, arising from the hydrogen bonding between the PVA and hydroxyl groups on the nanoparticle surface. The addition of nanoparticles favors the cross-linkage of the bulk PVA matrices, resulting in a higher melting temperature, and an enhanced thermal stability of the polymer matrix. 相似文献
18.
Enhanced transport of zerovalent iron nanoparticles in saturated porous media by guar gum 总被引:1,自引:0,他引:1
In order to ensure adequate mobility of zerovalent iron nanoparticles in natural aquifers, the use of a stabilizing agent
is necessary. Polymers adsorbed on the nanoparticle surface will give rise to electrosteric stabilization and will decrease
attachment to the surface soil grains. Water saturated sand-packed columns were used in this study to investigate the transport
of iron nanoparticle suspensions, bare or modified with the green polymer guar gum. The suspensions were prepared at 154 mg/L
particle concentration and 0.5 g/L polymer concentration. Transport experiments were conducted by varying the ionic strength,
ionic composition, and approach velocity of the fluid. Nanoparticle deposition rates, attachment efficiencies, and travel
distances were subsequently calculated based on the classical particle filtration theory. It was found that bare iron nanoparticles
are basically immobile in sandy porous media. In contrast, guar gum is able to ensure significant nanoparticle transport at
the tested conditions, regardless of the chemistry of the solution. Attachment efficiency values for guar gum-coated nanoparticles
under the various conditions tested were smaller than 0.066. Although the calculated travel distances may not prove satisfactory
for field application, the investigation attested the promising role of guar gum to ensure mobility of iron nanoparticles
in the subsurface environment. 相似文献
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Yilian Fernández-Afonso Gorka Salas Irene Fernández-Barahona Fernando Herranz Cordula Grüttner Jesús Martínez de la Fuente María del Puerto Morales Lucía Gutiérrez 《Particle & Particle Systems Characterization》2020,37(7):2000032
Advanced uses of smartphones are changing lifestyles, and may have a great impact in materials science in the near future. In this work, the use of these devices to develop fast, simple, and cheap methods to characterize magnetic nanoparticle suspensions is tested. A series of dilutions of a wide library of magnetic nanoparticles, composed of iron oxide materials in the range between 3 and 43 nm, with two different shapes and four different coatings is prepared. The colloid color is analyzed using the RGB (red, green, blue) color model. Ratios of these parameters are correlated with the suspension iron concentration and with the nanoparticles average size. A linear relationship between the color (in particular the G/R ratio) and both the colloid iron content and the particles size is found. The link between these parameters allows the development of two new methods to determine either the concentration or the particle size of magnetic nanoparticle suspensions just by acquiring images from suspensions of iron oxide magnetic nanoparticles with a smartphone. 相似文献
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W.L. Zhou E.E. Carpenter J. Lin A. Kumbhar J. Sims C.J. O'Connor 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):289-292
Pure metal iron nanoparticles are unstable in the air. By a coating iron on nanoparticle surface with a stable noble metal,
these air-stable nanoparticles are protected from the oxidation and retain most of the favorable magnetic properties, which
possess the potential application in high density memory device by forming self-assembling nanoarrays. Gold-coated iron core-shell
structure nanoparticles (Fe/Au) synthesized using reverse micelles were characterized by transmission electron microscopy
(TEM). The average nanoparticle size of the core-shell structure is about 8 nm, with about 6 nm diameter core and 1∼2 nm shell.
Since the gold shell is not epitaxial growth related to the iron core, the morié pattern can be seen from the overlapping
of iron core and gold shell. However, the gold shell lattice can be seen by changing the defocus of TEM. An energy dispersive
X-ray spectrum (EDS) also shows the nanoparticles are air-stable. The magnetic measurement of the nanoparticles also proved
successful synthesis of gold coated iron core-shell structure. The nanoparticles were then assembled under 0.5 T magnetic
field and formed parallel nanobands with about 10 μm long. Assembling two dimensional ordered nanoarrays are still under going.
Received 29 November 2000 相似文献