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1.
Quantifying plasmon resonance and interband transition contributions in photocatalysis of gold nanoparticle
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《中国物理 B》2021,30(7):77301-077301
Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However, the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood. Here, we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations. By photo-excitation of Na YF4:Eu~(3+)@Au composite structure, it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments, owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction. We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity. The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design. 相似文献
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应用有限元方法, 研究金纳米球壳对的几何结构参数及物理参量对其表面等离激元共振的散射及消光光谱的影响, 并根据等离激元杂化理论进行了理论分析. 结果表明, 随着金壳厚度的增加, 金纳米球壳对的散射及消光共振峰先发生蓝移而后红移, 而随着金纳米球壳间隙的减小, 或者随着金纳米球壳的内核尺寸或内核介质折射率的增大, 散射及消光共振峰均发生红移; 随着金壳厚度或内核尺寸减小, 或者随着内核介质折射率增大, 金纳米球壳对的散射与消光共振强度减弱, 而随着金壳间隙的减小, 金纳米球壳对的散射共振强度先增强后减弱, 而消光共振强度逐渐增强, 数值模拟与理论分析一致. 相似文献
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Mindaugas Maciulevičius Antanas Vinčiūnas Marijus Brikas Andrei Butsen Natalie Tarasenka Nikolai Tarasenko Gediminas Račiukaitis 《Applied Physics A: Materials Science & Processing》2013,111(1):289-295
Size of nanoparticles is an important parameter for their applications. The real-time monitoring is required for reliable and reproducible production of nanoparticles with controllable size. We present results of our research on development of the system for the online nanoparticle characterization during their production by a laser. The laser ablation chamber which allows measurements of surface plasmon resonance spectra during the nanoparticle generation process has been designed and fabricated. The online characterization system was tested by producing and modification of gold nanoparticles. Nanoparticles were generated by nanosecond-laser (wavelength 1064 nm) ablation of gold target in deionized water, and optimal conditions for the highest nanoparticle productivity were estimated. The mean diameter of nanoparticles was determined using their absorption spectra measured in the real-time during the ablation experiments and from the TEM images analysis, and it varied from 20 to 45 nm. The mismatch between nanoparticle diameters, estimated using these two methods, is due to the polydispersity of the generated nanoparticles. The further experiments of laser-induced modification of colloidal gold nanoparticles were carried out using second harmonic (wavelength 532 nm) of nanosecond Nd:YAG laser and alteration in nanoparticle size were acquired by the online measurement system. 相似文献
5.
Humidity sensor based on localized surface plasmon resonance of multilayer thin films of gold nanoparticles linked with myoglobin 总被引:1,自引:0,他引:1
Layer-by-layer self-assembled multilayer thin films of gold nanoparticles (GNPs) linked with myoglobin (Mb) show substantial sensitivity to humidity at room temperature according to measurements of localized surface plasmon resonance (LSPR) absorption that relies on the interparticle interaction present in the film. The sensor response is reversible, with response and recovery times as low as 5 s. The sensing mechanism is as follows: as the ambient humidity changes, Mb molecules change their size, making the GNP-to-GNP spacing and thereby the interparticle interaction change; the change in the interparticle interaction causes a change in the LSPR absorption of the multilayer thin film. We found that the LSPR band of the multilayer thin film was almost insensitive to both the surrounding refractive index and the adlayer thickness, rendering the multilayer-film-based humidity sensor highly immune to ambient disturbances. 相似文献
6.
The gold nanoparticle exhibits optical property of localized surface plasmon resonance (LSPR), which dynamically alters as the surface adsorbs new ligands. We carried out a semi-quantitative analysis with the method of multivariate curve resolution, observing that the adsorption of serum albumin on gold nanoparticle was best deciphered as two-mode competitive kinetics. Interestingly, for human serum albumin, the slower mode contributed considerably to the LSPR response of protein-conjugated surfaces, while in the case of bovine serum albumin the faster mode overwhelmed the slower one at high protein concentrations. The kinetic patterns were rationalized with diversity of biomolecular orientations on the nanoparticle surface. The simple but efficient protocol supports semi-quantitative analysis combining UV-vis spectroscopy with chemometrics method for distinguishing conjugation kinetics of different types of proteins on the surface of nanoparticles at nanomolar concentration. 相似文献
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相对于单一金属纳米材料,二金属复合纳米材料具有更大的潜在应用价值.基于时域有限差分方法,研究了SiO2-Ag-Au和SiO2-Au-Ag二金属三层纳米管的消光光谱,并对其局域表面等离激元共振(Localized Surface Plasmon Resonance,LSPR)特性进行了分析.研究发现,内核尺寸变大将导致上述两种金属纳米管LSPR峰红移;内层金属及外层金属壳层厚度增大均会导致其LSPR峰蓝移.银壳厚度变化对纳米管LSPR的调制作用大于金壳厚度变化造成的影响.上述现象可以利用等离激元杂化理论及自由电子和振荡电子变化的竞争机制进行分析. 相似文献
8.
The future implementation of integrated photonic devices requires the creation of nanostructures with well defined morphological and optical properties. To this end, we deposited size-selected gold nanoparticles produced by a gas phase aggregation cluster source on transparent substrates at room temperature with controlled impact energy. Interferometric optical detection measurements using a supercontinuum laser source demonstrated a blue-shifted plasmon resonance at the single particle level. The blue shift was observed to be more pronounced for small single clusters down to 3 nm in size. 相似文献
9.
Effects of thickness & shape on localized surface plasmon resonance of sexfoil nanoparticles
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《中国物理 B》2017,(1)
Localized surface plasmon(LSPR) resonance and sensing properties of a novel nanostructure(sexfoil nanoparticle)are studied using the finite-difference time-domain method. For the sandwich sexfoil nanoparticle, the calculated extinction spectrum shows that with the thickness of the dielectric layer increasing, long-wavelength peaks blueshift, while shortwavelength peaks redshift. Strong near-field coupling of the upper and lower metal layers leads to electric and magnetic field resonances; as the thickness increases, the electric field resonance gradually increases, while the magnetic field resonance decreases. The obtained refractive index sensitivity and figure of merit are 332 nm/RIU and 3.91 RIU~(-1), respectively. In order to obtain better sensing ability, we further research the LSPR character of monolayer Ag sexfoil nanoparticle. After a series of trials to optimize the thickness and shape, the refractive index sensitivity approximates 668 nm/RIU, and the greatest figure of merit value comes to 14.8 RIU~(-1). 相似文献
10.
Multipolar plasmon optical excitations at spherical gold nanoparticles and their manifestations in the particle images formatted
in the particle surface proximity are studied. The multipolar plasmon size characteristic: plasmon resonance frequencies and
plasmon damping rates were obtained within rigorous size dependent modelling. The realistic, frequency dependent dielectric
function of a metal was used. The distribution of light intensity and of electric field radial component at the flat square
scanning plane scattered by a gold sphere of radius 95 nm was acquired. The images resulted from the spatial distribution
of the full mean Poynting vector including near-field radial components of the scattered electromagnetic field. Monochromatic
images at frequencies close to and equal to the plasmon dipole and quadrupole resonance frequencies are discussed. The changes
in images and radial components of the scattered electromagnetic field distribution at the scanning plane moved away from
the particle surface from near-field to far-field region are discussed. 相似文献
11.
T. A. El-Brolossy T. Abdallah M. B. Mohamed S. Abdallah K. Easawi S. Negm H. Talaat 《The European physical journal. Special topics》2008,153(1):361-364
We report on the optical absorption properties of as
prepared gold naoparticles of different shapes and sizes measured by
photoacoustic (PA) method. The gold nanoparticles of two different shapes
(dots, rods) have been prepared using the seed mediated growth method. The
shape and the size of these different nanoparticles were determined by STM
measurements. PA spectra show the splitting of the surface plasmon resonance
(SPR) into two modes (transverse and longitudinal) in case of gold nanorods.
The increase in the aspect ratio of the nanorods leads to clear redshifts of
the longitudinal SPR. These shifts were used to determine the dielectric
constant of the surrounding medium and its variation with the aspect ratios. 相似文献
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We present extinction measurements on rectangular two-dimensional arrays of gold nanoparticles on a dielectric waveguide.
The spectra exhibit spectrally narrow bands of suppressed extinction within the particle–plasmon resonance, resulting from
destructive interference between the incident light field and the excited waveguide modes. The dependence of the spectral
position of these high-transmission bands on different waveguide modes is investigated in detail.
Received: 3 July 2001 / Published online: 10 October 2001 相似文献
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基于时域有限差分方法研究了几何形状、入射电场偏振方向、管壁厚度及内核和包埋介质的变化对椭圆截面金纳米管局域表面等离激元共振特性的影响.研究发现,当长轴固定时,短轴的减小将导致纳米管消光峰红移;入射电场偏振方向与椭圆长轴夹角的增大将导致消光峰红移;当颗粒整体尺寸不变时,管壁厚度减小同样会使得消光峰红移.此外,内核及包埋介质介电常数的增大均导致消光峰红移.利用等离激元杂化理论及自由电子和振荡电子竞争机理对上述现象进行了理论分析.
关键词:
消光光谱
局域表面等离激元共振
金纳米管
时域有限差分方法 相似文献
16.
Gold nanorods (AuNRs) are prepared through seeded growth approach. Synthesis parameters of the amount of cetyltrimethylammonium bromide (CTAB), and concentration of ascorbic acid (AA) were studied. We were aiming for an aspect ratio of 3 which could be achieved by a nanorod feature in the range of 45 nm length and 15 nm width. The absorption spectra are observed with an UV–visible NIR spectrophotometer and analysed theoretically. It is known that there are two plasmon resonance peaks for gold nanorod corresponding to transverse surface plasmon resonance (TSPR) and longitudinal surface plasmon resonance (LSPR), respectively. It is found that as the concentration of CTAB increases, the yield of NRs increases. As the concentration of AA increased from 0.05 to 0.2 M, LSP shifts to longer wavelength but upon further increasing the concentration, LSP shifts back to shorter wavelength. A linear relationship between LSPR wavelength and surrounding medium dielectric constant is obtained, which is in good agreement with the theoretical results. 相似文献
17.
金属纳米粒子的尺寸和形状对其物理和化学性质有很大影响,通常利用昂贵的透射电子显微镜和扫描电子显微镜进行其尺寸测量。为了节约测量成本,利用时域有限差分法研究了金纳米棒的尺寸与吸收峰的对应关系得到间接的测量方法。即当金纳米棒的纵横比增大时,横向等离子峰几乎没有变化,纵向等离子峰出现明显的红移,且红移速度随着金纳米棒半径的增大而增大。实际制备了两种不同尺寸的金纳米棒样品,通过理论模拟确定的金纳米棒的尺寸与利用透射电子显微镜测量的金纳米棒的尺寸符合的很好。 相似文献
18.
We present a label-free, nondestructive and high sensitivity biosensor by using the phase information of a gold nanoparticles enhanced ellipsometry signal. The refractive index (RI) resolution from ellipsometric phase information is of the order of 1.6×10(-6) RI units. Furthermore, spectroscopic and dynamic measurements show substantial change in the phase signal when biomolecules are coated on gold nanoparticles. The detection limit of our proposed technique is up to ~18?pM concentration of the target biomolecules. 相似文献
19.
Daria Riabinina Jianming Zhang Mohamed Chaker Joëlle Margot Dongling Ma Peter Tijssen 《Applied Physics A: Materials Science & Processing》2011,102(1):153-160
A significant shift of the surface plasmon resonance absorption spectrum of gold nanoparticles was obtained by the oxidation
of the nanoparticle surface via pulsed excimer laser irradiation. The high UV-light absorption of gold nanoparticles chemically
produced by citrate reduction led to the important surface oxidation up to 26%. As a result of laser irradiation, the gold/gold
oxide core-shell nanoparticles with little variation of the nanoparticle size were produced. After only 5 min of laser irradiation,
a 12-nm blue shift in surface plasmon resonance was obtained. The possible mechanisms governing the modification in surface
plasmon resonance by laser irradiation of gold nanoparticles were discussed. 相似文献
20.
《中国光学快报(英文版)》2016,(4)
We experimentally investigate the effects of the surface roughness of gold thin films on the properties of surface plasmon resonance. By annealing at different temperatures, film samples with different surface morphologies are obtained. Specifically, due to the diffusion of the gold atoms towards the films3 surface, the surface rootmean-square roughness decreases with the increasing annealing temperature. Then, we measure the surface plasmon resonance of the samples. The results show that the resonance angle of the surface plasmon resonance is sensitive to the root-mean-square roughness, and it gradually decreases by reducing the surface root-mean-square roughness.Yang 相似文献