CW-laser-induced morphological changes of a single gold nanoparticle on glass: observation of surface evaporation

Pulsed-laser heating of colloidal noble-metal nanoparticles in an aqueous solution induces morphological changes such as size reduction. However, the technique suffers disadvantages through polydispersed products. Here, we show that continuous-wave (CW) laser heating of single gold nanoparticles is...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2014-01, Vol.16 (48), p.26938-26945
Main Authors: Setoura, Kenji, Okada, Yudai, Hashimoto, Shuichi
Format: Article
Language:English
Subjects:
Air - analysis
Density
Evaporation
Glass - chemistry
Gold
Gold - chemistry
Heating
Illumination
Lasers
Metal Nanoparticles - chemistry
Metal Nanoparticles - ultrastructure
Nanoparticles
Nanostructure
Particle Size
Surface Properties
Transition Temperature
Volatilization
Water - chemistry
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Summary:Pulsed-laser heating of colloidal noble-metal nanoparticles in an aqueous solution induces morphological changes such as size reduction. However, the technique suffers disadvantages through polydispersed products. Here, we show that continuous-wave (CW) laser heating of single gold nanoparticles is capable of generating particles of smaller diameters with superb control in terms of exposure time and intensity. We show, based on calculations of particle temperatures under illumination, that surface evaporation below the boiling point of bulk gold occurs, resulting in a gradual diameter decrease in air. In our experiment, a focused illumination of Au NPs through an objective lens of a microscope provided peak-power densities (10(6)-10(7) W cm(-2)) equivalent to that of a typical nanosecond laser. Nevertheless the heating rate under CW laser illumination is much lower than that under pulsed-laser illumination, resulting in better control over nanoparticle heating and related morphological changes. Furthermore, the single-particle study of such heating helps us to clarify the evolution of such changes to a given particle.
ISSN:1463-9076
1463-9084
DOI:10.1039/c4cp03733b