Direct coating of gold nanoparticles with silica by a seeded polymerization technique

Mine, Eiichi; Yamada, Akira; Kobayashi, Yoshio; Konno, Mikio; Liz‐Marzán, Luis M.

doi:10.1016/s0021-9797(03)00422-3

Cited by 189 publications

(141 citation statements)

References 30 publications

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“…53,54 We focus here on the use of 5 and 10 nm diameter gold core SiO 2 −AuNPs (SiO 2 shells thicknesses of 15−20 nm) in order to explore a new pore size regime in NPSi as well as to achieve a fine degree of pore size and interpore spacing control. Figure 2 displays TEM and SEM images of 5 and 10 nm SiO 2 −AuNPs drop-cast from aqueous solutions of acetone and ultrapure water onto (100) Si wafers.…”

Section: Resultsmentioning

confidence: 99%

Catalyst Self-Assembly for Scalable Patterning of Sub 10 nm Ultrahigh Aspect Ratio Nanopores in Silicon

Smith

Patil

Ferralis

et al. 2016

ACS Appl. Mater. Interfaces

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Nanoporous silicon (NPSi) has received significant attention for its potential to contribute to a large number of applications, but has not yet been extensively implemented because of the inability of current state-of-the-art nanofabrication techniques to achieve sufficiently small pore size, high aspect ratio, and process scalability. In this work we describe the fabrication of NPSi via a modified metal-assisted chemical etching (MACE) process in which silica-shell gold nanoparticle (SiO 2 −AuNP) monolayers self-assemble from solution onto a silicon substrate. Exposure to the MACE etchant solution results in the rapid consumption of the SiO 2 spacer shell, leaving well-spaced arrays of bare AuNPs on the substrate surface. Particles then begin to catalyze the etching of nanopore arrays without interruption, resulting in the formation of highly anisotropic individual pores. The excellent directionality of pore formation is thought to be promoted by the homogeneous interparticle spacing of the gold core nanocatalysts, which allow for even hole injection and subsequent etching along preferred crystallographic orientations. Electron microscopy and image analysis confirm the ability of the developed technique to produce micrometer-scale arrays of sub 10 nm nanopores with narrow size distributions and aspect ratios of over 100:1. By introducing a scalable process for obtaining high aspect ratio pores in a novel size regime, this work opens the door to implementation of NPSi in numerous devices and applications.

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Section: Resultsmentioning

confidence: 99%

Catalyst Self-Assembly for Scalable Patterning of Sub 10 nm Ultrahigh Aspect Ratio Nanopores in Silicon

Smith

Patil

Ferralis

et al. 2016

ACS Appl. Mater. Interfaces

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“…Preparation of silica-coated gold nanoparticles (Au@SiO 2 ) Au@SiO 2 particles were prepared following the published method, 13 with slight modifications. First, gold nanoparticles were prepared using sodium citrate as a reductant.…”

Section: Resultsmentioning

confidence: 99%

“…The sol-gel seeded-growth process was applied to produce a silica shell on the gold nanoparticle surface. 13 Then, TEOS in ethanol (5 mM) was slowly added to the gold sol. The mixture was stirred for 10 min, and 5 ml of ammonia solution was added to the TEOS/ethanol/gold sol mixture with vigorous stirring.…”

Section: Experimental Procedures Materialsmentioning

confidence: 99%

Preparation of organic–ceramic–metal multihybrid particles and their organized assembly

Matsui

Parvin

Sato

et al. 2009

Polym J

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This paper describes the synthesis and assembly of multihybrid particles having a gold core, silica as an initial shell and polymethylmethacrylate (pMMA) as a second shell (Au@SiO 2 @pMMA). Multihybrid particles were synthesized in a stepwise manner. First, direct sol-gel coating of silica onto gold nanoparticles was carried out to prepare Au@SiO 2 particles. The Au@SiO 2 particles were modified with 3-(triethoxysilyl)propyl 2-bromo-2-methylpropanoate (BMPS), which is an initiator for atom transfer radical polymerization (ATRP) of MMA. Finally, bulk ATRP of MMA was conducted using BMPS-coated Au@SiO 2 particles. Au@SiO 2 @pMMA particles formed a closely packed monolayer at the air-water interface. The monolayer can be deposited onto a solid substrate using the Langmuir-Blodgett technique. Atomic force microscopy and scanning electron microscopy images of the deposited film show a uniform and closely packed monolayer film in an area a few tens-of-micrometers in size with no voids. Moreover, a clear Au core, silica shell and pMMA shell structure were observed in a transmission electron microscopy image of the transferred film. It is particularly interesting that the monolayer film shows no clear plasmon absorption of the gold core, as observed in the chloroform solution of the particle. Results show that a thick silica shell masked the monolayer film's plasmon absorption.

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“…For realization of this shell type microsphere, there are some main stages consist of the synthesis of metal cores, the modification of their surfaces with organic materials having functional groups, absorbing of seeding dielectric nanoparticles with diameter of 500 nm on modified cores and the synthesis of dielectric shell by the seeded growth technique [21,22].…”

Section: Shell Type Structure Microspherementioning

confidence: 99%

Analytical Modeling of Quality Factor for Shell Type Microsphere Resonators

Talebi¹,

Abbasian

Rostami³

2011

PIER B

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Abstract-In this paper, we have proposed a shell type dielectric microsphere resonator in order to enhance its quality factor. In this work we have assumed that the radius of dielectric microsphere is 12 µm and that the interior metal layer radius is 11.5 µm. We have obtained analytic equations for Vector potentials, characteristic equation, quality factor, resonance frequency and resonance location of TE modes. We have plotted these characteristics by MATLAB software and compared them with the normal microsphere characteristics.

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Direct coating of gold nanoparticles with silica by a seeded polymerization technique

Cited by 189 publications

References 30 publications

Catalyst Self-Assembly for Scalable Patterning of Sub 10 nm Ultrahigh Aspect Ratio Nanopores in Silicon

Catalyst Self-Assembly for Scalable Patterning of Sub 10 nm Ultrahigh Aspect Ratio Nanopores in Silicon

Preparation of organic–ceramic–metal multihybrid particles and their organized assembly

Analytical Modeling of Quality Factor for Shell Type Microsphere Resonators

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