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Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate.

Hao J, Han MJ, Xu Z, Li J, Meng X - Nanoscale Res Lett (2011)

Bottom Line: The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity.By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate.Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA. xmeng@stevens.edu.

ABSTRACT
Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

No MeSH data available.


Related in: MedlinePlus

SEM images of AgNPs multilayer films on glass slides prepared in a AgNO3/BuNH2 (5/2.5 mM) ethanolic solution with different reaction times: (a) 1.5 h, (b) 2 h, (c) 5 h, (d) 18 h, (e) 25 h, and (f) 40 h.
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Figure 1: SEM images of AgNPs multilayer films on glass slides prepared in a AgNO3/BuNH2 (5/2.5 mM) ethanolic solution with different reaction times: (a) 1.5 h, (b) 2 h, (c) 5 h, (d) 18 h, (e) 25 h, and (f) 40 h.

Mentions: To investigate the evolution of the nanostructured Ag films and the relationship between the Ag film structures and the SERS effect, the surface morphologies of the Ag/GL substrates were characterized by SEM observation. Figure 1 presents typical SEM images of the Ag/GL substrates prepared in a 5/2.5 mM AgNO3/BuNH2 solution at different reaction times of 1.5-40 h. At the beginning stage of the reaction (≤ 2 h), a thin monolayer (1st-layer) consisting of small sphere-like AgNPs formed on the glass surfaces as shown in Figure 1a,b. Most of AgNPs in the monolayer were isolated from their nearest neighbors for the 1.5 h reaction time (Figure 1a). As the reaction time increased to 2 h, the AgNPs grew and some of them appeared to contact each other, and the AgNPs monolayer exhibited a close-packed structure.


Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate.

Hao J, Han MJ, Xu Z, Li J, Meng X - Nanoscale Res Lett (2011)

SEM images of AgNPs multilayer films on glass slides prepared in a AgNO3/BuNH2 (5/2.5 mM) ethanolic solution with different reaction times: (a) 1.5 h, (b) 2 h, (c) 5 h, (d) 18 h, (e) 25 h, and (f) 40 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211326&req=5

Figure 1: SEM images of AgNPs multilayer films on glass slides prepared in a AgNO3/BuNH2 (5/2.5 mM) ethanolic solution with different reaction times: (a) 1.5 h, (b) 2 h, (c) 5 h, (d) 18 h, (e) 25 h, and (f) 40 h.
Mentions: To investigate the evolution of the nanostructured Ag films and the relationship between the Ag film structures and the SERS effect, the surface morphologies of the Ag/GL substrates were characterized by SEM observation. Figure 1 presents typical SEM images of the Ag/GL substrates prepared in a 5/2.5 mM AgNO3/BuNH2 solution at different reaction times of 1.5-40 h. At the beginning stage of the reaction (≤ 2 h), a thin monolayer (1st-layer) consisting of small sphere-like AgNPs formed on the glass surfaces as shown in Figure 1a,b. Most of AgNPs in the monolayer were isolated from their nearest neighbors for the 1.5 h reaction time (Figure 1a). As the reaction time increased to 2 h, the AgNPs grew and some of them appeared to contact each other, and the AgNPs monolayer exhibited a close-packed structure.

Bottom Line: The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity.By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate.Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA. xmeng@stevens.edu.

ABSTRACT
Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

No MeSH data available.


Related in: MedlinePlus