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Role of Temperature in the Growth of Silver Nanoparticles Through a Synergetic Reduction Approach

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ABSTRACT

This study presents the role of reaction temperature in the formation and growth of silver nanoparticles through a synergetic reduction approach using two or three reducing agents simultaneously. By this approach, the shape-/size-controlled silver nanoparticles (plates and spheres) can be generated under mild conditions. It was found that the reaction temperature could play a key role in particle growth and shape/size control, especially for silver nanoplates. These nanoplates could exhibit an intensive surface plasmon resonance in the wavelength range of 700–1,400 nm in the UV–vis spectrum depending upon their shapes and sizes, which make them useful for optical applications, such as optical probes, ionic sensing, and biochemical sensors. A detailed analysis conducted in this study clearly shows that the reaction temperature can greatly influence reaction rate, and hence the particle characteristics. The findings would be useful for optimization of experimental parameters for shape-controlled synthesis of other metallic nanoparticles (e.g., Au, Cu, Pt, and Pd) with desirable functional properties.

No MeSH data available.


The size evolution process of silver nanoparticles at different temperatures: a 17–38°C and b 45–55°C.
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Figure 4: The size evolution process of silver nanoparticles at different temperatures: a 17–38°C and b 45–55°C.

Mentions: To track the formation and growth with time, the dimensions of plates were checked. Figure 4 shows the growth process of silver plates at different temperature stages of 17–38°C (a) and 45–55°C (b). Because the data were collected at different time intervals of 5 min for lower temperatures (<38°C) and 3 min for relatively high temperatures (>42°C), the data were analysed separately. In general, the particle size increases with time at 17–55°C: from 90 to 180 nm for the edge length of triangular plates and from 25 to 48 nm for the diameter of silver spheres. The reaction rate denoted by the slope of particle growth curves shows that the higher the temperature the faster the particle grows. Additionally, it appears that a size jump occurred from 90 to 180 nm for plates and/or 25 to 48 nm for spheres when the temperature is around 32–38°C, as observed in TEM images (Figure 1d) and the growth trend (Figure 3). The possible fusion growth mechanism occurred at this stage has been discussed above. This is different from the observation of particle grow with time through Ostwald ripening process at room temperature [53]. The details in this growth mechanism need to be investigated in the near future. Nonetheless, the effect of temperature on particle size increase is significant under the reported conditions.


Role of Temperature in the Growth of Silver Nanoparticles Through a Synergetic Reduction Approach
The size evolution process of silver nanoparticles at different temperatures: a 17–38°C and b 45–55°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211407&req=5

Figure 4: The size evolution process of silver nanoparticles at different temperatures: a 17–38°C and b 45–55°C.
Mentions: To track the formation and growth with time, the dimensions of plates were checked. Figure 4 shows the growth process of silver plates at different temperature stages of 17–38°C (a) and 45–55°C (b). Because the data were collected at different time intervals of 5 min for lower temperatures (<38°C) and 3 min for relatively high temperatures (>42°C), the data were analysed separately. In general, the particle size increases with time at 17–55°C: from 90 to 180 nm for the edge length of triangular plates and from 25 to 48 nm for the diameter of silver spheres. The reaction rate denoted by the slope of particle growth curves shows that the higher the temperature the faster the particle grows. Additionally, it appears that a size jump occurred from 90 to 180 nm for plates and/or 25 to 48 nm for spheres when the temperature is around 32–38°C, as observed in TEM images (Figure 1d) and the growth trend (Figure 3). The possible fusion growth mechanism occurred at this stage has been discussed above. This is different from the observation of particle grow with time through Ostwald ripening process at room temperature [53]. The details in this growth mechanism need to be investigated in the near future. Nonetheless, the effect of temperature on particle size increase is significant under the reported conditions.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

This study presents the role of reaction temperature in the formation and growth of silver nanoparticles through a synergetic reduction approach using two or three reducing agents simultaneously. By this approach, the shape-/size-controlled silver nanoparticles (plates and spheres) can be generated under mild conditions. It was found that the reaction temperature could play a key role in particle growth and shape/size control, especially for silver nanoplates. These nanoplates could exhibit an intensive surface plasmon resonance in the wavelength range of 700&ndash;1,400 nm in the UV&ndash;vis spectrum depending upon their shapes and sizes, which make them useful for optical applications, such as optical probes, ionic sensing, and biochemical sensors. A detailed analysis conducted in this study clearly shows that the reaction temperature can greatly influence reaction rate, and hence the particle characteristics. The findings would be useful for optimization of experimental parameters for shape-controlled synthesis of other metallic nanoparticles (e.g., Au, Cu, Pt, and Pd) with desirable functional properties.

No MeSH data available.