Nonlinear Optical Properties of Molecularly Bridged Gold Nanoparticle Arrays

Novak, James P.; Brousseau, Louis; Vance, Fredrick W.; Johnson, Robert C.; Lemon, Buford I.; Hupp, Joseph T.; Feldheim, Daniel L.

doi:10.1021/ja003129h

Cited by 148 publications

(130 citation statements)

References 18 publications

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“…By using b w = 0.56 10 À30 esu, as reported in the literature, we have found out b nano = 3.8 10 À24 esu for 80 nm gold nanorod and 4.2 10 À24 esu for DNA adsorbed gold nanorod, which is about 3-4 orders of magnitude higher than the b values reported for the best available molecular chromophores [21][22][23][24][25][26][27]37] and 1-2 orders of magnitude higher than the b value reported for gold nanoparticles. [6,22,38,39] This higher b value for nanorods with respect to nanosphere can be due to several facts and these are 1) The presence of {110} facets, which is not present in nanospheres, is known to give rise to strong absorption energies; 2) the surface electromagnetic field of rods is the highest relative to other shapes due to the rods high curvatures (called "the lightning rod" effect [40] ); 3) the presence of multipoles; and 4) possibility of single-photon resonance enhancement. The optical responses of particles that are small compared to the wavelength can be described usually in the framework of electric-dipole approximation.…”

Section: Resultsmentioning

confidence: 99%

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Darbha

Shanker

Singh

et al. 2008

Chemistry A European J

111

166

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Infectious diseases caused by the human immunodeficiency virus (HIV) remain the leading killers of human beings worldwide, and function to destabilize societies in Africa, Asia, and the Middle East. Driven by the need to detect the presence of HIV viral sequence, here we demonstrate that the second-order nonlinear optical (NLO) properties of gold nanorods can be used for screening HIV-1 viral DNA sequence without any modification, with good sensitivity (100 pico-molar) and selectivity (single base-pair mismatch). The hyper-Rayleigh scattering (HRS) intensity increases 45 times when a label-free 145-mer, ss-gag gene DNA, was hybridized with 100 pM target DNA. The mechanism of HRS intensity change has been discussed with experimental evidence for higher multipolar contribution to the NLO response of gold nanorods.

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Section: Resultsmentioning

confidence: 99%

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Darbha

Shanker

Singh

et al. 2008

Chemistry A European J

111

166

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“…Gold nanoparticles (AuNPs) are the most stable MNP; they can be synthesized with different sizes and shapes; and they are easily functionalized with diverse ligands 3 . AuNPs have numerous applications in nanomedicine 4,5 , biotechnology 6 , microelectronics 7 , optics [8][9][10] , gas sensing [11][12][13] and catalysis [14][15][16][17][18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

Molybdenum Trioxide Thin Films Doped With Gold Nanoparticles Grown by a Sequential Methodology: Photochemical Metal-Organic Deposition (Pmod) and Dc-Magnetron Sputtering

Castillo

Buono-Core

Manzur

et al. 2016

J. Chil. Chem. Soc.

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Gold nanoparticles (AuNPs) were deposited by DC-magnetron sputtering onto molybdenum trioxide (MoO 3 ) thin films grown by Photochemical MetalOrganic Deposition (PMOD) on Si(100) and borosilicate glass substrates. The chemical, optical and morphology properties of the films were studied by UV/ Vis Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD). SEM revealed that AuNPs formed after 5 s of sputtering. AuNPs are spherical and have both an average diameter of 18 nm and a relatively narrow size distribution. As the deposition time increases, larger structures are formed by an aggregation of AuNPs. XPS studies of the AuNP/MoO 3 films on Si(100) showed the presence of Mo(VI) and Mo(V), which indicated that the films were primarily non-stoichiometric molybdenum oxides. The occurrence of oxygen vacancies in the substrate play an important role to stabilize the AuNPs. , gas sensing 11-13 and catalysis [14][15][16][17][18][19][20] . KeywordsAuNPs have been prepared using various approaches that can be divided into physical and chemical methods. Included among the chemical methods are reduction 21, photochemistry using UV irradiation 22,23 , photochemistry using X-ray irradiation 24 , sonochemistry 25,26 , and sonoelectrochemistry 27 . A physical method that can be used is cathodic deposition using magnetron sputtering. This physical method has several advantages over chemical syntheses, such as a lack of surface contamination from solvent or precursor molecules, which may be important for subsequent assays and/or applications. Furthermore, physical deposition is cheaper and faster and does not damage the environment [28][29][30] .Gold catalysts with selected support materials can efficiently promote many reactions that normally occur at much higher temperatures or with lower selectivity when catalyzed by other metals. It has been shown that AuNPs supported on metal oxides exhibit unique activity at room temperature because of a meta-stable interatomic bonding between gold atoms 31 . It has been shown that substrates such as ceria 32 , titania 33,34 and titanates 35 can stabilize AuNPs in which oxygen vacancies play an important role in the stabilizing effect. It is generally accepted that interfaces provide adequate sites for chemical reactions, and metallic Au surfaces are required as reservoirs for a determined reactant 36,37 . Gold nanoparticles also play an important role in the development of chemical and biological sensors. A sensor usually has two functional components: one component selectively binds with the analyte, and the other provides transduction of this interaction into a detectable signal 38 . Considering the chromogenic properties of molybdenum oxide on the one hand and the catalytic properties of gold nanoparticles on the other, a binary system that is formed by molybdenum oxide coated with gold nanoparticles could potentially be of use in the field of catalysis and/or in the fabrication of new specific sensors. For example, i...

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“…[3,4] Other techniques for the controlled assembly of Au particles include the use of template molecules with defined symmetry [5] and interparticle spacing, [6] metal coordination, [7] a polymer-mediated "BM" strategy coupled with hydrogen bonding, [8] and Langmuir techniques. [9] Although some success has been achieved, [8,10] the formation of aggregates of controllable size and shape in solution remains far from routine.…”

Section: Introductionmentioning

confidence: 99%

From Discrete Particles to Spherical Aggregates: A Simple Approach to the Self‐Assembly of Au Colloids

Zhong

Subramanian

Highfield

et al. 2005

Chemistry A European J

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Here we demonstrate a simple, template-free approach to the formation of spherical gold aggregates through the reduction of HAuCl4 by NaBH4, in the presence of cysteine (Cys) as a capping agent. The resulting aggregates are quite stable in solution. The pH of the solution and the molar ratio of Au:Cys are two key empirical factors in the formation of such highly ordered aggregates. At slightly alkaline pH (7-10) and with Au:Cys ratios ranging from 1:0.5 to 1:2, spherical Au aggregates of 30-80 nm are formed. At lower Cys ratios (Au:Cys> or =1:0.5) very loosely linked aggregates are formed; however, at very high Cys ratios (Au:Cys< or =1:3), highly dispersed Au particles of 2-4 nm are obtained, which are virtually indistinguishable from the original colloidal form. Aggregate size is influenced markedly by component concentration; a 3-fold increase in standard levels resulted in Au spherical aggregates of a larger size, 200-500 nm. In addition, we used a combination of Cys and lysine (Lys) as a capping agent/cross-linker and found that the morphology of the Au colloid aggregates can be easily manipulated from a linear to a spherical form by adjusting the proportions of Cys and Lys in the capping agent/cross-linker mixture. The introduction of mercapto (SH)-containing organic acids reduced the cross-linking ability of Cys, especially in the case of long-chain acids. Complete disruption of the spherical aggregates highlights the importance of Cys per se. An explanation of this ordered self-assembly process is proposed, in the context of the known surface chemistry of Au colloids.

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Nonlinear Optical Properties of Molecularly Bridged Gold Nanoparticle Arrays

Cited by 148 publications

References 18 publications

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Gold‐Nanorod‐Based Sensing of Sequence Specific HIV‐1 Virus DNA by Using Hyper‐Rayleigh Scattering Spectroscopy

Molybdenum Trioxide Thin Films Doped With Gold Nanoparticles Grown by a Sequential Methodology: Photochemical Metal-Organic Deposition (Pmod) and Dc-Magnetron Sputtering

From Discrete Particles to Spherical Aggregates: A Simple Approach to the Self‐Assembly of Au Colloids

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