Introduction

Крейбиг, У.; Vollmer, Michael

doi:10.1007/978-3-662-09109-8_1

Cited by 364 publications

(617 citation statements)

References 145 publications

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“…Intrinsic size effects for particles smaller than the mean free path of electrons in bulk gold were accounted for in the framework of the extended Drude model assuming size-and temperature-independent contribution from the interband transitions. 32,36,37 Thus, the complex dielectric function of gold reads:…”

Section: Computational Framework Dielectric Function Of Nanosized Golmentioning

confidence: 99%

Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold

et al. 2019

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An overarching computational framework unifying several optical theories to describe the temporal evolution of gold nanoparticles (GNPs) during a seeded growth process is presented. To achieve this, we used the inexpensive and widely available optical extinction spectroscopy, to obtain quantitative kinetic data. In situ spectra collected over a wide set of experimental conditions were regressed using the physical model, calculating light extinction by ensembles of GNPs during the growth process. This model provides temporal information on the size, shape, and concentration of the particles, and any electromagnetic interactions between them. Consequently, we were able to describe the mechanism of GNP growth and divide the process into distinct genesis periods. We provide explanations for several longstanding mysteries, e.g., the phenomena responsible for the purple-greyish hue during the early stages of GNP growth, the complex interactions between nucleation, growth and aggregation events, and a clear distinction between agglomeration and electromagnetic interactions. The presented theoretical formalism has been developed in a generic fashion so that it can readily be adapted to other nanoparticulate formation scenarios such as the genesis of various metal nanoparticles. KeywordsGold nanoparticles, seeded growth, UV-Vis spectroscopy, computational modeling, kinetics and mechanism.reason, there is a great need for a general and easily adaptable theoretical framework that utilizes the practical application of OES in the study of nanomaterial formation.So far, several investigations have addressed the mechanistic aspects during the (seeded) growth of GNPs using various characterization techniques such as atomic force microscopy (AFM), 5,14,18 electrophoretic measurements, 19,20 redox potential/pH measurements, 18-20 dynamic light scattering (DLS), 14,19,21 ex situ TEM, 4,5,7,14,[19][20][21][22][23] in situ TEM, 4,5 , and X-ray scattering. 6,7,13,23,24 Many of these studies follow the process also using ex situ 5,[19][20][21][22] or in situ 14,23,24 UV-vis spectroscopy but the information is treated merely qualitatively.From the plethora of research, some of which was summarized above, we know that the processes of seeded growth is typically accompanied by nucleation of new particles. 5,25 This could either be in a homogeneous fashion, 25 or in the close vicinity of the already present seed surface 5 (so called true catalytic secondary nucleation 26 or, equivalently, near surface nucleation followed by particle mediated growth 5 ). Additional complications arise from the possibility of agglomeration/aggregation invoked in many studies to describe the transient enhanced extinction in the wavelength range 600-800 nm, namely, the temporary purple-greyish colour of the suspension. 7,[18][19][20]27 Biggs et al. 18 and Chow and Zukoski 19 explained this in the light of the reduced colloidal stability in the presence of Au(III) in solution. Later, Rodriguez-Gonzalez and co-workers noticed that a homogeneous Au(III)→Au(I...

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Section: Computational Framework Dielectric Function Of Nanosized Golmentioning

confidence: 99%

Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold

et al. 2019

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“…[1] Furthermore, the absorption peak can be shifted by the adsorption of biomolecules [2] or by coating the nanoparticle (NP) surfacew ith other metal oxides, [3] which are often used for sensor or catalyst applications,r espectively. Amongv arious metals,s uch as gold, silver,c opper, platinum, and palladium, that display SPR in the UV/Vis/near-IR region, silver exhibits the highest efficiency excitation, [4] and, compared with gold, ah igher sensitivity to ac hange in the dielectric constant of the surrounding mediumf or biomolecule detection. [5] Moreover,t hrough shape transformation,s ilver nanostructures were converted into hollow,p orous, andf rame nanostructures by using the galvanic replacement reaction with more noble metal ions, such as gold, palladium, and platinum, that have ah igherr edox potential than Ag + /Ag (0.80 eV versus as tandard hydrogen electrode (SHE)).…”

Section: Introductionmentioning

confidence: 99%

Close‐Packed Two‐Dimensional Silver Nanoparticle Arrays: Quadrupolar and Dipolar Surface Plasmon Resonance Coupling

Yun

Hong

Acapulco

et al. 2015

Chemistry A European J

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Silver nanoparticles (NPs) ranging in size from 40 to 100 nm were prepared in high yield by using an improved seed-mediated method. The homogeneous Ag NPs were used as building blocks for 2D assembled Ag NP arrays by using an oil/water interface. A close-packed 2D array of Ag NPs was fabricated by using packing molecules (3-mercaptopropyltrimethoxysilane) to control the interparticle spacing. The homogeneous 2D Ag NP array exhibited a strong quadrupolar cooperative plasmon mode resonance and a dipolar red-shift relative to individual Ag NPs suspended in solution. A well-arranged 2D Ag NP array was embedded in polydimethylsiloxane film and, with biaxial stretching to control the interparticle distance, concomitant variations of the quadrupolar and dipolar couplings were observed. As the interparticle distance increased, the intensity of the quadrupolar cooperative plasmon mode resonance decreased and dipolar coupling completely disappeared. The local electric field of the 2D Ag NP array was calculated by using finite difference time domain simulation and qualitatively showed agreement with the experimental measurements.

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“…520 nm. 27 Upon increasing the number of depositions, a new broad band appeared as a shoulder in the region near 610 nm. The intensity of this new peak was proportional to the number of layers.…”

Section: Preparation and Characterization Of Au Np Films On Solid Submentioning

confidence: 99%

Solid Phase Extraction of Neutral Analytes through Silica Gel Coated with Layers of Au Nanoparticles Self‐Assembled with Alkanethiols

Liu

2008

J Chinese Chemical Soc

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In this study, we used Au nanoparticle (NP)-coated silica gel as a solid phase extraction sorbent for the preconcentration of neutral analytes (steroid drugs). The sorbent was fabricated using two alkanethiol self-assembly processes: one to deposit the Au NPs onto a 3-aminopropyltrimethoxysilane-modified silica gel and the other to functionalize the surfaces of the Au NPs. A large volume of the steroid solution was passed through the silica gel to facilitate adsorption mediated by hydrophobic interactions between the steroids and the hydrophobic moieties on the silica gel surface. Extraction of the steroids was accomplished by flushing the silica gel with a low-polarity solvent. In this preliminary study, we found that the particle size of the silica gel and the number of layers of Au NPs coated on the silica gel both affected the preconcentration performance for the steroids. When using six layers of Au NPs coated on 5-20-mm silica gel, the detection limits for steroids were below 80 ng L -1 ; the preconcentration efficiency was over 170-fold higher than that of the original steroid solution. Our findings provide further evidence that nanotechnology has much to benefit analytical science.

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Introduction

Cited by 364 publications

References 145 publications

Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold

Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold

Close‐Packed Two‐Dimensional Silver Nanoparticle Arrays: Quadrupolar and Dipolar Surface Plasmon Resonance Coupling

Solid Phase Extraction of Neutral Analytes through Silica Gel Coated with Layers of Au Nanoparticles Self‐Assembled with Alkanethiols

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