Surface Enhanced Raman Spectroscopy

 

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Surface Enhanced Raman spectroscopy (SERS)

Surface-enhanced Raman scattering (SERS) is one of the most practical analysis techniques for molecular structure characterization and trace-amount detection due to unique fingerprint signals and large signal enhancement ratio.

By utilizing of SERS for detection applications, we can realize..

1.Universal molecule detection
2.Non-invasive and safe detection
3.Trace molecule detection even at single molecule level.

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1. Fabrication of sub-20 nm nanopattern for SERS

To maximize SERS signal intensity, fabrication of well-defined ultra-small nanostructures with large-area uniformity is an essential factor.

Among the various fabrication tools, direct self-assembly of block copolymers is one of most attractive candidate for sub-20 nm pattern generation. By changing the total molecular weight and the volume fraction of the minority block, different geometries such as lines, dots, and holes can be obtained.

We reported sequentially self-assembled nanoplasmonic arrays achieved by the synergic combination of sub-micron-scale polystyrene (PS) particle self-assembly and sub-10 nm BCP self-assembly without using high-cost top-down lithography.

Different length scale self-assembly nanostructures provide multiple advantages for SERS analysis in terms of signal amplification and measurement reproducibility.

 

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2. Solvent-assisted nanotransfer printing(S-nTP) based SERS applications.

 

a) S-ntp onto diverse surfaces and SERS analysis

The SERS substrate based on the transfer-printed Ag nanowires showed clearly resolved Raman peaks of rhodamine 6G (R6G) molecules even at a low concentration of 10-9 M

As an example of a near-term application, we demonstrate that Ag nanowires printed on the inner surface of a vial glass can enhance SERS signals, enabling direct and convenient detection of molecules dispersed in a solution at an extremely low concentration. Also, transfer printing of Ag nanowires onto the surface of a fruit enables direct and rapid detection of pesticide residues on the surface using a SERS analysis.

 

b) Fabrication of 3D cross-point plasmonic nanoarchitectures via S-ntp technique

We have demonstrated highly SERS-active and uniform 3D cross-point plasmonic nanostructures over a large area based on solvent-assisted high-resolution nanotransfer printing. In term of SERS performance, we successfully demonstrated a high-performance, uniform, and low-cost SERS substrate with an average enhancement factor of up to 4.1 × 107

Moreover, S-nTP enabled the fabrication of a SERS contact lens that can detect glucose in an aqueous solution. These promising results suggest that S-nTP can be extensively utilized for various nanoscale sensing platforms.

 

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[REFERENCE]

■Jae Won Jeong, Se Ryeun Yang, Yoon Hyung Hur, Seong Wan Kim, Kwang Min Baek, Soonmin Yim, Hyun-Ik Jang, Jae Hong Park, Seung Yong Lee, Chong-Ook Park & Yeon Sik Jung*, ”High-resolution nanotransfer printing applicable to diverse surfaces via interface-targeted adhesion switching”Nature Communications, 2014, 5, 5387  [PDF file]

■Kwang Min Baek, Jong Min Kim, Jae Won Jeong, Seung Yong Lee*, and Yeon Sik Jung*, ”Sequentially Self-Assembled Rings-in-Mesh Nanoplasmonic Arrays for Surface-Enhanced Raman Spectroscopy” Chemistry of Materials, 2015, Online published  [PDF File]

■Jae Won Jeong, Md Masud Parvez Arnob, Kwang-Min Baek, Seung-Yong Lee, Wai-Chuan Shih and Yeon Sik Jung*, ”Three-dimensional Cross-point Plasmonic Nano-architectures Containing Dense and Regular Hot Spots for Surface-Enhanced Raman Spectroscopy Analysis” Advanced Materials, 2016, Online published  [PDF File]