Determination of Aspect-Ratio Distribution in Gold Nanowires Using Absorption Spectra and Transmission Electron Microscopy Techniques

Omi, Hiroo

doi:10.5772/37507

Cited by 2 publications

(12 citation statements)

References 34 publications

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“…22 respectively (Figure 3 a and b). Consistent with the literature, 35,43 as-synthesized Au-nanowires using…”

Section: Influence Of Citrate-to-gold Molar Ratio ([Cit]/[au])supporting

confidence: 62%

“…Careful inspection of the absorption spectra of Au-NPs reveals that the maximum absorption (λ max ) of Au-NPs synthesized at high microwave power (e.g., 45 W) is blue-shifted compared to the absorption of a sample synthesized at low microwave power (e.g., 25 W) as shown in Figure c. For spherical Au-NPs, a blue-shift in λ max is usually attributed to the formation of Au-NPs smaller in size. , However, UV–vis spectroscopy alone is an inadequate technique for particle size and morphology analysis since the SPR of Au-NPs is highly morphology dependent; thus, the use of alternative techniques such as electron microscopy is necessary to elucidate the reason for the observed λ max shift. ,,,,, Thus, transmission electron microscopy (TEM) has been extensively used to observe the mean particle size and size distribution of Au-NPs. ,, …”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, a weak shoulder is observed at ca.750 nm for Au-NPs synthesized under 25 W, that may probably be attributed to the presence of high aspect ratio (>2) Au-NPs observed in TEM images (ESI Figure S2). 34,35 Typical TEM image of the Au-NPs synthesized under constant citrate-to-gold molar ratio of 6/1 and 4 mL min -1 flow rate at 36 W is shown in Figure 1b. The high magnification HR-TEM image (inset of Figure 1b) proves Au-NPs (average aspect ratio of 1.37) with lattice spacing consistent with Au 0 (111) have been synthesised by the system.…”

Section: Influence Of Microwave Irradiation Intensitymentioning

confidence: 99%

“…27,37 However, UV-vis spectroscopy alone is an inadequate technique for particle size and morphology analysis since the SPR of Au-NPs is highly morphology dependent, thus the use of alternative techniques such as electron microscopy is necessary to elucidate the reason of the observed λmax shift. 9,26,27,34,35,38 Thus transmission electron microscopy (TEM) has been extensively used to observe the mean particle size and size distribution of Au-NPs. 13,15,35 Mean particle size / nm…”

Section: Influence Of Microwave Irradiation Intensitymentioning

confidence: 99%

“…9,26,27,34,35,38 Thus transmission electron microscopy (TEM) has been extensively used to observe the mean particle size and size distribution of Au-NPs. 13,15,35 Mean particle size / nm…”

Section: Influence Of Microwave Irradiation Intensitymentioning

confidence: 99%

See 4 more Smart Citations

Controllable Synthesis of Gold Nanoparticles in Aqueous Solution by Microwave Assisted Flow Chemistry

Bayazit

Yue

Cao

et al. 2016

ACS Sustainable Chem. Eng.

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The development of energy efficient, reproducible and high throughput approaches to gold nanoparticles (Au-NPs) synthesis have gained increasing attention over the past decades due to their application in biomedicine, sensor and catalysis. In this work, single mode microwave irradiation is for the first time combined with microflow chemistry to fabricate Au-NPs continuously and reproducibly with controllable size in an aqueous solution. The major experimental parameters including microwave power, citrate-to-gold molar ratio ([Cit]/[Au]) and reaction residence time have been investigated systematically. As indicated by TEM, the mean particle width of the synthesised Au-NPs is between 4 and 15 nm with mean aspect ratio between ~1.4 and 2.2 after only 90 s microwave irradiation. Furthermore the Au particle morphology can be manipulated from nanowires to nanoparticles by adjusting the [Cit]/[Au] ratio. HRTEM analysis of the produced Au-NPs and UV-vis spectroscopy suggest a correlation between the red-shifted surface plasmon resonance peak and the particle aspect ratio that is probably dependent on the creation of particle-particle junctions, which alter both the size and the aspect ratio of the Au-NPs. The synthesis further demonstrated high reproducibility.

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“…22 respectively (Figure 3 a and b). Consistent with the literature, 35,43 as-synthesized Au-nanowires using…”

Section: Influence Of Citrate-to-gold Molar Ratio ([Cit]/[au])supporting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Section: Influence Of Microwave Irradiation Intensitymentioning

confidence: 99%

Section: Influence Of Microwave Irradiation Intensitymentioning

confidence: 99%

“…9,26,27,34,35,38 Thus transmission electron microscopy (TEM) has been extensively used to observe the mean particle size and size distribution of Au-NPs. 13,15,35 Mean particle size / nm…”

Section: Influence Of Microwave Irradiation Intensitymentioning

confidence: 99%

See 3 more Smart Citations

Controllable Synthesis of Gold Nanoparticles in Aqueous Solution by Microwave Assisted Flow Chemistry

Bayazit

Yue

Cao

et al. 2016

ACS Sustainable Chem. Eng.

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show abstract

Competitive Seeded Growth: An Original Tool to Investigate Anisotropic Gold Nanoparticle Growth Mechanism

et al. 2019

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The influence of initial seed structure on final nanoparticle geometry has been investigated by an original "competitive approach" using SAXS, UV-Vis Spectroscopy and TEM analysis. Herein by using the seed mediated gold nanoparticle growth, seeds with different size and crystalline structure were synthesized and injected into the same growth media. The seeds were chosen due to their different growth evolution into two different morphologies. CTAB coated single crystalline seeds grow into rod like shapes whereas citrate coated multi-crystalline seeds mainly grow into wheat shape polycrystalline particles with small elongation called nanobeans in coexistence with a large quantity of spheres. When seeds are added into the same growth media for competition, a mixture of the different morphologies is obtained. By controlling the number of added competing seeds in the solution, it was found that the multi-crystalline seeds have a higher growth rate than the single crystalline seeds. This has a direct impact on the final distribution of size and morphologies of the nanoparticles. The consequence is a large tendency towards nanobean and sphere structure formation even when a small number of multi-twinned seeds is added in the solution. This method demonstrates the importance of the nature of defects hidden in the initial seed and proves that these defaults are inherited to the final nanocrystal throughout the growth stage from the beginning of the growth. This competitive seeded growth approach is an easy way to identify the influence of seeds morphologies in synthetic pathway of nanoparticles formation.

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Determination of Aspect-Ratio Distribution in Gold Nanowires Using Absorption Spectra and Transmission Electron Microscopy Techniques

Cited by 2 publications

References 34 publications

Controllable Synthesis of Gold Nanoparticles in Aqueous Solution by Microwave Assisted Flow Chemistry

Controllable Synthesis of Gold Nanoparticles in Aqueous Solution by Microwave Assisted Flow Chemistry

Competitive Seeded Growth: An Original Tool to Investigate Anisotropic Gold Nanoparticle Growth Mechanism

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