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Rapid synthesis of monodisperse Au nanospheres through a laser irradiation-induced shape conversion, self-assembly and their electromagnetic coupling SERS enhancement.

Liu D, Li C, Zhou F, Zhang T, Zhang H, Li X, Duan G, Cai W, Li Y - Sci Rep (2015)

Bottom Line: We develop a facile and effective strategy to prepare monodispersed Au spherical nanoparticles by two steps.These gold nanospheres and their self-assembled arrays possess distinct physical and chemical properties.It will make them as an excellent and promising candidate for applying in sensing and spectroscopic enhancement, catalysis, energy, and biology.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, P. R. China [2] Department of Materials Science &Engineering, University of Science and technology of China, Hefei 230026, P. R. China.

ABSTRACT
We develop a facile and effective strategy to prepare monodispersed Au spherical nanoparticles by two steps. Large-scale monocrystalline Au nanooctahedra with uniform size were synthesized by a polyol-route and subsequently Au nanoparticles were transformed from octahedron to spherical shape in a liquid under ambient atmosphere by non-focused laser irradiation in very short time. High monodispersed, ultra-smooth gold nanospheres can be obtained by simply optimizing the laser fluence and irradiation time. Photothermal melting-evaporation model was employed to get a better understanding of the morphology transformation for the system of nanosecond pulsed-laser excitation. These Au nanoparticles were fabricated into periodic monolayer arrays by self-assembly utilizing their high monodispersity and perfect spherical shape. Importantly, such Au nanospheres arrays demonstrated very good SERS enhancement related to their periodic structure due to existence of many SERS hot spots between neighboring Au nanospheres caused by the electromagnetic coupling in an array. These gold nanospheres and their self-assembled arrays possess distinct physical and chemical properties. It will make them as an excellent and promising candidate for applying in sensing and spectroscopic enhancement, catalysis, energy, and biology.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration of nanosecond laser-irradiation induced shape transformation of the octaheral Au NPs in water.Jm, threshold for melting to liquid phase of bulk gold; Jevp, threshold for boiling to evaporation of bulk gold; Jp, laser fluence acting on gold NPs.
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f9: Schematic illustration of nanosecond laser-irradiation induced shape transformation of the octaheral Au NPs in water.Jm, threshold for melting to liquid phase of bulk gold; Jevp, threshold for boiling to evaporation of bulk gold; Jp, laser fluence acting on gold NPs.

Mentions: With the help of equation (5), it is easy to understand the mechanism of the photothermal melting-evaporation of shape changes from Au nanooctahedron to nanosphere under nanosecond pulsed-laser irradiation. Figure 9 shows a schematic to illustrate the morphological evolution of the octahedral Au NPs under nanosecond pulsed-laser irradiation. When laser fluence Jp is smaller than the bulk melting threshold Jm, only particle heating is achieved or even a slight melting sharp corner is taken place. Or perhaps a surface melting of particles will be achieved due to their high surface-area-to-volume ratio61. While at the condition of Jm < JP < Jevp, a bulk melting occurs and the particle turns into ultra-spherical liquid phase. Once the heat dissipation to the surrounding medium, particles solidify into ultra-spherical phase for keeping. However, when the condition of JP > Jevp is met, the particle reaches the boiling temperature and starts to evaporate. The laser-induced size reduction takes place, and the slightly smaller and much smaller Au NPs are observed as a result of the layer-by-layer surface evaporation.


Rapid synthesis of monodisperse Au nanospheres through a laser irradiation-induced shape conversion, self-assembly and their electromagnetic coupling SERS enhancement.

Liu D, Li C, Zhou F, Zhang T, Zhang H, Li X, Duan G, Cai W, Li Y - Sci Rep (2015)

Schematic illustration of nanosecond laser-irradiation induced shape transformation of the octaheral Au NPs in water.Jm, threshold for melting to liquid phase of bulk gold; Jevp, threshold for boiling to evaporation of bulk gold; Jp, laser fluence acting on gold NPs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4286736&req=5

f9: Schematic illustration of nanosecond laser-irradiation induced shape transformation of the octaheral Au NPs in water.Jm, threshold for melting to liquid phase of bulk gold; Jevp, threshold for boiling to evaporation of bulk gold; Jp, laser fluence acting on gold NPs.
Mentions: With the help of equation (5), it is easy to understand the mechanism of the photothermal melting-evaporation of shape changes from Au nanooctahedron to nanosphere under nanosecond pulsed-laser irradiation. Figure 9 shows a schematic to illustrate the morphological evolution of the octahedral Au NPs under nanosecond pulsed-laser irradiation. When laser fluence Jp is smaller than the bulk melting threshold Jm, only particle heating is achieved or even a slight melting sharp corner is taken place. Or perhaps a surface melting of particles will be achieved due to their high surface-area-to-volume ratio61. While at the condition of Jm < JP < Jevp, a bulk melting occurs and the particle turns into ultra-spherical liquid phase. Once the heat dissipation to the surrounding medium, particles solidify into ultra-spherical phase for keeping. However, when the condition of JP > Jevp is met, the particle reaches the boiling temperature and starts to evaporate. The laser-induced size reduction takes place, and the slightly smaller and much smaller Au NPs are observed as a result of the layer-by-layer surface evaporation.

Bottom Line: We develop a facile and effective strategy to prepare monodispersed Au spherical nanoparticles by two steps.These gold nanospheres and their self-assembled arrays possess distinct physical and chemical properties.It will make them as an excellent and promising candidate for applying in sensing and spectroscopic enhancement, catalysis, energy, and biology.

View Article: PubMed Central - PubMed

Affiliation: 1] Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, P. R. China [2] Department of Materials Science &Engineering, University of Science and technology of China, Hefei 230026, P. R. China.

ABSTRACT
We develop a facile and effective strategy to prepare monodispersed Au spherical nanoparticles by two steps. Large-scale monocrystalline Au nanooctahedra with uniform size were synthesized by a polyol-route and subsequently Au nanoparticles were transformed from octahedron to spherical shape in a liquid under ambient atmosphere by non-focused laser irradiation in very short time. High monodispersed, ultra-smooth gold nanospheres can be obtained by simply optimizing the laser fluence and irradiation time. Photothermal melting-evaporation model was employed to get a better understanding of the morphology transformation for the system of nanosecond pulsed-laser excitation. These Au nanoparticles were fabricated into periodic monolayer arrays by self-assembly utilizing their high monodispersity and perfect spherical shape. Importantly, such Au nanospheres arrays demonstrated very good SERS enhancement related to their periodic structure due to existence of many SERS hot spots between neighboring Au nanospheres caused by the electromagnetic coupling in an array. These gold nanospheres and their self-assembled arrays possess distinct physical and chemical properties. It will make them as an excellent and promising candidate for applying in sensing and spectroscopic enhancement, catalysis, energy, and biology.

No MeSH data available.


Related in: MedlinePlus