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Sandwich-like layer-by-layer assembly of gold nanoparticles with tunable SERS properties

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ABSTRACT

Sandwich-like layer-by-layer thin films consisting of polyelectrolytes and gold nanoparticles were utilized to construct surface-enhanced Raman scattering (SERS) substrates with tunable SERS properties. It is found that both the size of the nanoparticles in the layers and the interlayer distance significantly influence the SERS performance of the multilayered thin film. These simple, low-cost, easily processable and controllable SERS substrates have a promising future in the field of molecular sensing.

No MeSH data available.


SEM images of multilayer thin films consisted of PDDA and Au NPs of different sizes: (a) SSS, (b) SBS, (c) BSB, (d) BBB.
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Figure 2: SEM images of multilayer thin films consisted of PDDA and Au NPs of different sizes: (a) SSS, (b) SBS, (c) BSB, (d) BBB.

Mentions: Typical sandwich-like multilayer thin films were prepared by sequential deposition of polyelectrolytes and Au NPs. For example, the BSB thin film formed after the substrate was alternately dipped into PDDA/big Au NP/PDDA/small Au NP/PDDA/big Au NP solutions. From the point of view of Au NPs, these sandwich-like nanostructures are ideal for the evaluation of NP size effects on the SERS performance of NP assemblies. Fig. 2 presents the SEM images of the SSS, SBS, BSB and BBB multilayer thin films. Undoubtedly, both small and big Au NPs were assembled into the thin films, and the NP size did not change during the assembly process. It is clear that the sandwich-like LbL assembly of Au NPs occurs via lateral expansion mode, which is consistent with previous results [18,22–23]. Interestingly, compared with the BSB thin film, there were more small Au NPs in the SBS thin film, though the number of big Au NPs was about the same. This phenomenon may result from the steric hindrance of the pre-assembled big Au NPs. In other words, the first big NP layer in the BSB thin film is more unfavorable for the following deposition of small NPs, resulting in less small NPs in the non-stratified thin film. What is more, these LbL thin films are relatively uniform (Figure S1, Supporting Information File 1), which is important for reproducible SERS performance [18].


Sandwich-like layer-by-layer assembly of gold nanoparticles with tunable SERS properties
SEM images of multilayer thin films consisted of PDDA and Au NPs of different sizes: (a) SSS, (b) SBS, (c) BSB, (d) BBB.
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4979642&req=5

Figure 2: SEM images of multilayer thin films consisted of PDDA and Au NPs of different sizes: (a) SSS, (b) SBS, (c) BSB, (d) BBB.
Mentions: Typical sandwich-like multilayer thin films were prepared by sequential deposition of polyelectrolytes and Au NPs. For example, the BSB thin film formed after the substrate was alternately dipped into PDDA/big Au NP/PDDA/small Au NP/PDDA/big Au NP solutions. From the point of view of Au NPs, these sandwich-like nanostructures are ideal for the evaluation of NP size effects on the SERS performance of NP assemblies. Fig. 2 presents the SEM images of the SSS, SBS, BSB and BBB multilayer thin films. Undoubtedly, both small and big Au NPs were assembled into the thin films, and the NP size did not change during the assembly process. It is clear that the sandwich-like LbL assembly of Au NPs occurs via lateral expansion mode, which is consistent with previous results [18,22–23]. Interestingly, compared with the BSB thin film, there were more small Au NPs in the SBS thin film, though the number of big Au NPs was about the same. This phenomenon may result from the steric hindrance of the pre-assembled big Au NPs. In other words, the first big NP layer in the BSB thin film is more unfavorable for the following deposition of small NPs, resulting in less small NPs in the non-stratified thin film. What is more, these LbL thin films are relatively uniform (Figure S1, Supporting Information File 1), which is important for reproducible SERS performance [18].

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Sandwich-like layer-by-layer thin films consisting of polyelectrolytes and gold nanoparticles were utilized to construct surface-enhanced Raman scattering (SERS) substrates with tunable SERS properties. It is found that both the size of the nanoparticles in the layers and the interlayer distance significantly influence the SERS performance of the multilayered thin film. These simple, low-cost, easily processable and controllable SERS substrates have a promising future in the field of molecular sensing.

No MeSH data available.