Gold Nanotubes Synthesized via Magnetic Alignment of Cobalt Nanoparticles as Templates

Schwartzberg, Adam M.; Olson, Tammy Y.; Talley, Chad E.; Zhang, Jin Z.

doi:10.1021/jp076034b

Cited by 68 publications

(75 citation statements)

References 16 publications

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“…The GRR is one of the most efficient strategies to combine different metals in a single nanostructure. This strategy provides a remarkably simple route to produce complex metallic nanostructures with controllable hollow interiors by means of the reaction of solid metal nanostructures, used as sacrificial templates (usually Ag [19,[64][65][66][67][68], but also Cu [69][70][71], Co [70,[72][73][74][75][76][77], Pd [78,79], Mg [80] or alloys Pd-Cu [81]) and a precursor containing a relatively more noble metal ion (Au, Pd, or Pt), in a process by which the composition of the template is modified while retaining its initial morphology. Figure 2A [82].…”

Section: Synthesis Of Hollow Nanostructuresmentioning

confidence: 99%

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

et al. 2016

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Metallic nanostructures have received great attention due to their ability to generate surface plasmon resonances, which are collective oscillations of conduction electrons of a material excited by an electromagnetic wave. Plasmonic metal nanostructures are able to localize and manipulate the light at the nanoscale and, therefore, are attractive building blocks for various emerging applications. In particular, hollow nanostructures are promising plasmonic materials as cavities are known to have better plasmonic properties than their solid counterparts thanks to the plasmon hybridization mechanism. The hybridization of the plasmons results in the enhancement of the plasmon fields along with more homogeneous distribution as well as the reduction of localized surface plasmon resonance (LSPR) quenching due to absorption. In this review, we summarize the efforts on the synthesis of hollow metal nanostructures with an emphasis on the galvanic replacement reaction. In the second part of this review, we discuss the advancements on the characterization of plasmonic properties of hollow nanostructures, covering the single nanoparticle experiments, nanoscale characterization via electron energy-loss spectroscopy and modeling and simulation studies. Examples of the applications, i.e. sensing, surface enhanced Raman spectroscopy, photothermal ablation therapy of cancer, drug delivery or catalysis among others, where hollow nanostructures perform better than their solid counterparts, are also evaluated.

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Section: Synthesis Of Hollow Nanostructuresmentioning

confidence: 99%

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

et al. 2016

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“…This has also been observed experimentally for hollow gold nanospheres. 27 Note that these morphological redshifting effects are much stronger than the shift in Fig. 1.4 which was due to the increasing size of the scatterer.…”

Section: Core-shell Structuresmentioning

confidence: 82%

Electromagnetic Metamaterials: Homogenization and Effective Properties of Mixtures

Sihvola¹

2017

World Scientific Handbook of Metamaterials and Plasmonics

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This chapter presents homogenization principles for metamaterials and dielectric mixtures. The focus is on the principles with which homogenization brings forth emergence: such qualitatively new properties in the effective characterization that are not present in the constituent components that make the medium. The classical Maxwell Garnett mixing result is paralleled with the deterministic scattering problem of a composite sphere, and the resulting equivalence is exploited in translating known mixing results to scattering and absorption properties of simple scatterers and vice versa. Emphasis is given to the way mixing can lead to situations where the composite obeys an unexpected dispersion behavior that is not directly predictable from the knowledge of the dispersion of the component materials. The characteristics of the localized resonances and their dependence on geometrical and structural parameters in plasmonic nanoparticles are analyzed. Theoretical bounds for the effective permittivity of mixtures are discussed as well as situations in which these bounds can allow enhanced polarization and percolation effects.

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“…One such factor is environmental oxygen. GE in HGN synthesis has traditionally been performed under aerobic conditions [31][32][33][34][35][36][37][39][40][41][42]45 Co 2 B NP scaffolds were synthesized via the well-established nucleation of Co 2+ ions with NaBH 4 , using citrate as a capping ligand. Briefly, a 100 mL solution of 0.40 mM CoCl 2 ·6H 2 O and 4.0 mM Na 3 C 6 H 5 O 7 ·2H 2 O was prepared in a 500 mL round-bottom flask and deaerated by bubbling with nitrogen for 1 h. During this time, the solution was stirred at 700 rpm with a magnetic stir bar.…”

Section: −41mentioning

confidence: 99%

“…For one hollow structure of note, the hollow gold nanosphere (HGN), the SPR may be tuned across the visible wavelengths and into the nearinfrared by adjusting the ratio of outer diameter to shell thickness (the aspect ratio). 31 Increasing the aspect ratio and red-shifting the SPR may be accomplished by either increasing the diameter or thinning the shell. Because of this twofold tunability, the diameter and SPR frequency can in principle be independently adjusted, allowing the formation of targeted photoactivated structures of specific size and optical functionality.…”

Section: ■ Introductionmentioning

confidence: 99%

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Highly Tunable Hollow Gold Nanospheres: Gaining Size Control and Uniform Galvanic Exchange of Sacrificial Cobalt Boride Scaffolds

Lindley

Cooper

Rojas‐Andrade

et al. 2018

ACS Appl. Mater. Interfaces

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In principle, the diameter and surface plasmon resonance (SPR) frequency of hollow metal nanostructures can be independently adjusted, allowing the formation of targeted photoactivated structures of specific size and optical functionality. Although tunable SPRs have been reported for various systems, the shift in SPR is usually concomitant with a change in particle size. As such, more advanced tunability, including constant diameter with varying SPR or constant SPR with varying diameter, has not been properly achieved experimentally. Herein, we demonstrate this advanced tunability with hollow gold nanospheres (HGNs). HGNs were synthesized through galvanic exchange using cobalt-based nanoparticles (NPs) as sacrificial scaffolds. Co 2 B NP scaffolds were prepared by sodium borohydride nucleation of aqueous cobalt chloride and characterized using UV−vis, dynamic light scattering, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. Careful control over the size of the Co 2 B scaffold and its galvanic conversion is essential to realize fine control of the resultant HGN diameter and shell thickness. In pursuit of size control, we introduce B(OH) 4 − (the final product of NaBH 4 hydrolysis) as a growth agent to obtain hydrodynamic diameters ranging from ∼17−85 nm with relative standard deviation <3%. The highly monodisperse Co 2 B NPs were then used as scaffolds for the formation of HGNs. In controlling HGN shell thickness and uniformity, environmental oxygen was shown to affect both the structural and optical properties of the resultant gold shells. With careful control of these key factors, we demonstrate an HGN synthesis that enables independent variation of diameter and shell thickness, and thereby SPR, with unprecedented uniformity. The new synthesis method creates a truly tunable plasmonic nanostructure platform highly desirable for a wide range of applications, including sensing, catalysis, and photothermal therapy. KEYWORDS: cobalt boride, size control, sodium borohydride, galvanic exchange, hollow gold nanospheres, surface plasmon resonance ■ INTRODUCTIONPlasmonic metal nanostructures exhibit beneficial optical properties owing to their surface plasmon resonance (SPR), the collective oscillation of conduction band electrons that manifests as strong absorption, and/or scattering at the oscillation frequency.1,2 As oscillation frequency is structure dependent, the SPR may be tuned by changing the size or shape of the nanoparticle (NP). 3−5 This tunability positions plasmonic metal NPs as highly attractive components in nanomedicine, 6−12 optoelectronics, 13−18 sensing, [6][7][8][9]13,18,19 and solar energy conversion. 20−24 In these applications, hollow metal nanostructures have distinct advantages over their solid metal counterparts including lower mass per particle for reduced material costs, higher surface-area-to-volume ratio for increased density of loading or catalytic sites, and enhanced plasmonic performance in applications like surface-enhanced Raman scattering (SERS), drug ...

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Gold Nanotubes Synthesized via Magnetic Alignment of Cobalt Nanoparticles as Templates

Cited by 68 publications

References 16 publications

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

Electromagnetic Metamaterials: Homogenization and Effective Properties of Mixtures

Highly Tunable Hollow Gold Nanospheres: Gaining Size Control and Uniform Galvanic Exchange of Sacrificial Cobalt Boride Scaffolds

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