Shape-dependent plasmon resonances of gold nanoparticles

Nehl, Colleen L.; Hafner, Jason H.

doi:10.1039/b714950f

Cited by 447 publications

(341 citation statements)

References 82 publications

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“…It is consistent with the previous reports that the longitudinal band of GNRs is more sensitive to the local environment around GNRs than the transverse band [42][43][44][45]. This result suggested that the aggregation of GNRs takes place in a side-by-side manner [46,47].…”

Section: +supporting

confidence: 82%

Colorimetric assay of lead using unmodified gold nanorods

et al. 2012

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Lead poisoning in adults can affect the peripheral and central nervous systems, the kidneys, and blood pressure. Thus, the development of environment-friendly and simple methods for Pb 2+ detection is of great importance. Herein, a label-free colorimetric method has been developed for the detection of Pb 2+ based on the conformational switch from single-stranded DNA to G-quadruplex. The electrostatic interactions between DNA probe and gold nanorods (GNRs) induce GNRs to space closely. However, the electrostatic interaction is not strong enough to change the suspension state of GNRs. In the presence of Pb 2+ , the formation of G-quadruplexes increases the surface charge density around DNA, which is expected to strengthen the electrostatic interaction between the GNRs and the DNA. Therefore, the longitudinal absorption of GNRs decreased because the stronger interaction induced aggregation of GNRs. Importantly, the decrease in longitudinal absorption is proportional to concentration of Pb 2+ . By monitoring the change of absorbance, Pb 2+ can be detected at a level of 3 nM with a linear range from 5 nM to 1 μM. The overall test only takes a few minutes and very little interference is observed from other metal ions. The major advantages of this method are its low cost, convenience, simplicity, sensitivity, and specificity.

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Section: +supporting

confidence: 82%

Colorimetric assay of lead using unmodified gold nanorods

et al. 2012

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“…In these methods the metal ions are reduced but need thermal treatment. 9 In this paper, we report precise dopoing of gold nanoparticles in borate matrix, viz. "lithium-borate rubyglass-ceramics" without thermal treatment and addition of any reducing agent.…”

Section: Introductionmentioning

confidence: 99%

Ionic to Electronic Conductivity Studies of Lithium-Borate Ruby-Glass-Ceramics Containing Gold Nano Particles

Shivaprakash

Anavekar

2011

Transactions of the Indian Ceramic Society

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Glass-ceramics containing Au nanoparticles have been synthesized in the glass composition 30Li 2 O-70B 2 O 3 with HAuCl 4 .3H 2 O as dopant. The characteristic ruby colour has been observed which is attributed to the surface plasmon resonance of the Au nanoparticles, uniformly embedded in the glass matrix. The imparted red colour due to the presence of gold nanoparticles has been confirmed by studying the optical absorption spectra using UV-VIS spectrometer in the visible range (400-1000 nm) which show a characteristic absorption peak at ~560 nm. In order to check the crystallization/ amorphous nature, the samples were powdered and characterized using X-ray diffraction (XRD). The microstructural modifications in the samples due to the addition of Au have been recorded using scanning electron microscopy (SEM). Further, the electron spin resonance (ESR) studies reveal that the electronic state of gold is either Au 0 or Au + . AC conductivity studies have been performed at room temperature over a frequency range 100 to 10 MHz. The ac conductivity data is fitted by Almond-West law with power exponent 's'. The dc conductivity is found to be increasing with the increase of temperature for a typical ruby glass, but almost constant with dopant concentration.[Keywords : Ruby-glass, Gold nanoparticles, Optical absorption, SPR, Transport properties] IntroductionRuby glasses containing gold nanoparticles or other noble metal nanoparticles have been extensively investigated for the past decades because of their excellent properties such as ultrafast optical response and large third order non-linear susceptibility. [1][2][3][4] This kind of glasses are expected to be promising materials for ultrafast optical switches and optical circuits with micrometer size. Hence, preparation and characterization of materials containing noble metal nanoparticles is the most challenging task for researchers in the area of materials science. Glasses containing metal nanoparticles look very distinctive with different colours. Since the quantum size effects and enhanced surface effects are expected to influence the electronic and optical properties at much smaller particle sizes, it leads to more interest for researchers to fabricate the metal nanoparticles in glasses. 5,6 Such investigated gold-ruby glasses are used not only as decorative glasswares but also for many technological applications in the field of electrical and optical communications. Silicate ruby glasses are synthesized mainly by using HAuCl 4 .3H 2 O along with a reducing agent, such as tin based compounds, and then annealing the glass for several hours at a particular temperature. 7,8 Metal nanoparticles in glasses are also precipitated using electron beam and laser irradiation. In these methods the metal ions are reduced but need thermal treatment.

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“…Among them, urchin-like or branched gold particles with a rough surface are of great significance. The high surface area endows them excellent performance in catalysis, surface plasmon resonance (SPR) [7], surface-enhanced Raman spectra (SERS) [8], electronic devices, and biological applications [1,2,9].In particular, owing to the existence of a large electromagnetic field enhancement at the tips of branched particles, a strong SERS activity can be detected with intensity over 10 7 and a relatively high reproducibility [8]. In addition, the urchin-like structure leads to large SPR shift from 500 to 800 nm and tunable SPR enhancement light scattering and absorption, making them novel and highly effective contrast agents for in vivo cancer diagnosis and therapy [10].…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of hollow urchin-like gold nanoparticles and their catalytic activity

et al. 2012

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The galvanic replacement reaction between Ag nanoparticles (NPs) and HAuCl 4 followed by addition of ascorbic acid led to the formation of AuNPs sharing both urchin-like and hollow structures. The AgNPs took as sacrificial templates to guide the hollow structure and the intermediates provided rough surface and active sites for the further deposition of AuNPs, which originated from the reduction of excess HAuCl 4 by ascorbic acid. These unique structured AuNPs presented excellent optical properties and great advantages in catalysis applications.

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Shape-dependent plasmon resonances of gold nanoparticles

Cited by 447 publications

References 82 publications

Colorimetric assay of lead using unmodified gold nanorods

Colorimetric assay of lead using unmodified gold nanorods

Ionic to Electronic Conductivity Studies of Lithium-Borate Ruby-Glass-Ceramics Containing Gold Nano Particles

Facile synthesis of hollow urchin-like gold nanoparticles and their catalytic activity

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