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Compact Shielding of Graphene Monolayer Leads to Extraordinary SERS-Active Substrate with Large-Area Uniformity and Long-Term Stability.

Liu X, Wang J, Wu Y, Fan T, Xu Y, Tang L, Ying Y - Sci Rep (2015)

Bottom Line: Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface.Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform.Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

View Article: PubMed Central - PubMed

Affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.

ABSTRACT
Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface. Despite the long history of this technology, SERS has yet to become a sophisticated analytical tool in practical applications. A major obstacle is the absence of high-quality and stable SERS-active substrate. In this work, we report a monolayer graphene-shielded periodic metallic nanostructure as large-area uniform and long-term stable SERS substrate. The monolayer graphene acting as a corrosion barrier, not only greatly enhanced stability, but also endowed many new features to the substrate, such as alleviating the photo-induced damages and improving the detection sensitivity for certain analytes that are weakly adsorbed on the conventional metallic substrates. Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform. Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

No MeSH data available.


Related in: MedlinePlus

Photographs of an 4 × 4 graphene-shielded SERS substrate array from a different angle (a, b) and SERS intensity mapping collected in an 5 × 5 mm area with a step size of 50 μm (acquisition time for each point is 0.1 s) after the substrate was treated with 10 μM CV and washed thoroughly, which were constructed based on the band intensities at 1167 cm−1 (c) and 1617 cm−1 (d). (e) Average intensity distribution of the 1167 cm−1 peak of the 4 × 4 SERS sensing spots (average of 20 randomly selected locations for each spot with 1s acquisition time, using 10× objective). The dark blue and light blue zones represent ±5 and ±5 ~ 10% intensity variation, respectively.
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f3: Photographs of an 4 × 4 graphene-shielded SERS substrate array from a different angle (a, b) and SERS intensity mapping collected in an 5 × 5 mm area with a step size of 50 μm (acquisition time for each point is 0.1 s) after the substrate was treated with 10 μM CV and washed thoroughly, which were constructed based on the band intensities at 1167 cm−1 (c) and 1617 cm−1 (d). (e) Average intensity distribution of the 1167 cm−1 peak of the 4 × 4 SERS sensing spots (average of 20 randomly selected locations for each spot with 1s acquisition time, using 10× objective). The dark blue and light blue zones represent ±5 and ±5 ~ 10% intensity variation, respectively.

Mentions: Sensor arrays are practically useful in high-throughput or multi-analyte analysis282930. Interestingly, graphene-shielded SERS sensing spots array could also be prepared by a similar approach. Before silver coating, a facile technique was adopted to generate the SERS sensing array. The excessive nanospheres on Si wafer were removed by an adhesive tape with predrilled patterned holes, resulting in a patterned nanospheres spot array. After silver coating and graphene transferring, the graphene-shielded SERS sensing array was obtained. Figure 3a shows a typical 4 × 4 array containing 16 sensing spots. Each spot was ~500 μm in diameter with an average center-to-center distance ~1.5 mm. The iridescent structural colors from each spot were easily identified (Fig. 3b), suggesting the homogeneous morphology and prominent plasmonic properties of the substrate. But, monolayer graphene on the substrate was hard to distinguish by naked eyes, due to its low color contrast. We collected SERS spectra of the obtained graphene-shielded sensing array after exposure to same concentration of CV. The SERS mapping based on the intensities at 1167 cm−1 and 1617 cm−1 are shown in Fig. 3c,d, which were perfectly matched the optical images of the array (Fig. 3a,b). Further, to investigate the signal reproducibility of the sensing array, the SERS spectra collected at 20 randomly chosen points (for each spot) are shown in Figure S8. The average Raman intensities of the characteristic 1617 cm−1 peak are also quantitatively displayed in Fig. 3e, which shows that 7 of the total 16 sensing spots exhibiting an intensity variation within 5%, while the rest 9 spots are ~10%. The relative standard deviation of the averaged intensity is 6.4%, indicating homogeneous site enhancement distribution and potentialities of the array in quantitative analysis.


Compact Shielding of Graphene Monolayer Leads to Extraordinary SERS-Active Substrate with Large-Area Uniformity and Long-Term Stability.

Liu X, Wang J, Wu Y, Fan T, Xu Y, Tang L, Ying Y - Sci Rep (2015)

Photographs of an 4 × 4 graphene-shielded SERS substrate array from a different angle (a, b) and SERS intensity mapping collected in an 5 × 5 mm area with a step size of 50 μm (acquisition time for each point is 0.1 s) after the substrate was treated with 10 μM CV and washed thoroughly, which were constructed based on the band intensities at 1167 cm−1 (c) and 1617 cm−1 (d). (e) Average intensity distribution of the 1167 cm−1 peak of the 4 × 4 SERS sensing spots (average of 20 randomly selected locations for each spot with 1s acquisition time, using 10× objective). The dark blue and light blue zones represent ±5 and ±5 ~ 10% intensity variation, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663485&req=5

f3: Photographs of an 4 × 4 graphene-shielded SERS substrate array from a different angle (a, b) and SERS intensity mapping collected in an 5 × 5 mm area with a step size of 50 μm (acquisition time for each point is 0.1 s) after the substrate was treated with 10 μM CV and washed thoroughly, which were constructed based on the band intensities at 1167 cm−1 (c) and 1617 cm−1 (d). (e) Average intensity distribution of the 1167 cm−1 peak of the 4 × 4 SERS sensing spots (average of 20 randomly selected locations for each spot with 1s acquisition time, using 10× objective). The dark blue and light blue zones represent ±5 and ±5 ~ 10% intensity variation, respectively.
Mentions: Sensor arrays are practically useful in high-throughput or multi-analyte analysis282930. Interestingly, graphene-shielded SERS sensing spots array could also be prepared by a similar approach. Before silver coating, a facile technique was adopted to generate the SERS sensing array. The excessive nanospheres on Si wafer were removed by an adhesive tape with predrilled patterned holes, resulting in a patterned nanospheres spot array. After silver coating and graphene transferring, the graphene-shielded SERS sensing array was obtained. Figure 3a shows a typical 4 × 4 array containing 16 sensing spots. Each spot was ~500 μm in diameter with an average center-to-center distance ~1.5 mm. The iridescent structural colors from each spot were easily identified (Fig. 3b), suggesting the homogeneous morphology and prominent plasmonic properties of the substrate. But, monolayer graphene on the substrate was hard to distinguish by naked eyes, due to its low color contrast. We collected SERS spectra of the obtained graphene-shielded sensing array after exposure to same concentration of CV. The SERS mapping based on the intensities at 1167 cm−1 and 1617 cm−1 are shown in Fig. 3c,d, which were perfectly matched the optical images of the array (Fig. 3a,b). Further, to investigate the signal reproducibility of the sensing array, the SERS spectra collected at 20 randomly chosen points (for each spot) are shown in Figure S8. The average Raman intensities of the characteristic 1617 cm−1 peak are also quantitatively displayed in Fig. 3e, which shows that 7 of the total 16 sensing spots exhibiting an intensity variation within 5%, while the rest 9 spots are ~10%. The relative standard deviation of the averaged intensity is 6.4%, indicating homogeneous site enhancement distribution and potentialities of the array in quantitative analysis.

Bottom Line: Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface.Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform.Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

View Article: PubMed Central - PubMed

Affiliation: College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.

ABSTRACT
Surface-enhanced Raman scattering (SERS) can significantly boost the inherently weak Raman scattering signal and provide detailed structural information and binding nature of the molecules on the surface. Despite the long history of this technology, SERS has yet to become a sophisticated analytical tool in practical applications. A major obstacle is the absence of high-quality and stable SERS-active substrate. In this work, we report a monolayer graphene-shielded periodic metallic nanostructure as large-area uniform and long-term stable SERS substrate. The monolayer graphene acting as a corrosion barrier, not only greatly enhanced stability, but also endowed many new features to the substrate, such as alleviating the photo-induced damages and improving the detection sensitivity for certain analytes that are weakly adsorbed on the conventional metallic substrates. Besides, our fabrication strategy were also capable of fabricating the reproducible SERS sensing spots array, which may serve as a promising high-throughput or multi-analyte sensing platform. Taken together, the graphene-shielded SERS substrate holds great promise both in fundamental studies of the SERS effect and many practical fields.

No MeSH data available.


Related in: MedlinePlus