OVERVIEW OF THE 4n4SERS SUBSTRATE4n4SERS基板の概要
◆Improvement in Enhancement Factor: In 2023, the enhancement factor improved by approximately 16 times, changing from the 4n4SERS substrate to the 4n4SERS 4×4 substrate.
Figure 1: The 4n4SERS substrate uses noble metal nanoparticles and exhibits significantly different optical and electromagnetic properties compared to bulk materials, due to the Localized Surface Plasmon Resonance (LSPR) effect.
As a result, this significantly enhances the Surface-Enhanced Raman Scattering (SERS) effect. These characteristics make it useful for molecular-level diagnostics, utilizing the high optical properties of HighQuant NPs.
Furthermore, the 4n4SERS ４ｘ４ (Figure, right side), developed in 2023, is significantly improved and generates higher electric field intensity compared to our conventional 4n4SERS substrate (Figure, left side).
Consequently, the enhancement factor is further increased, and the detection limit when using the 4n4SERS ４ｘ４ has been significantly improved.
SCHEMATIC DIAGRAM OF THE 4n4SERS SUBSTRATE 4n4SERS基板の模式図
The 4n4SERS chip adopts PHORNANO’s patented robust heat sink technology, which prevents the analyte from overheating. (Patent No.: WO2022266691A1)
— The structure beneath the cover film of the 4n4SERS substrate features PHORNANO’s unique/proprietary structure, as shown in the figure.
A 5μℓ analyte sample is dried onto the 4n4SERS chip using nanotechnology.
The Raman laser (red) focuses on the analyte, generating a Raman signal (blue) which is then enhanced and reflected back to the Raman probe by the 4n4SERS chip.
The system also enables quantitative analysis SERS in some cases, producing an enhancement factor of up to one million times.
OVERVIEW OF THE LITERATURE文献の概要
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ーSensitive and high laser damage threshold substrates for surface-enhanced Raman scattering based on gold and silver nanoparticlesー
Dr.FelixMayr：Linz Institute for Organic Solar Cells (LIOS), Institute of Physical Chemistry, Johannes Kepler University Linz, Linz, Austria
Abstract
Surface-enhanced Raman scattering (SERS) is a sensitive and fast technique for sensing applications such as chemical trace analysis.
However, a successful, high-throughput practical implementation necessitates the availability of simple-to-use and economical SERS substrates.
In this work, we present a robust, reproducible, flexible, and yet cost-effective SERS substrate suited for the sensitive detection of analytes at near-infrared (NIR) excitation wavelengths.
The fabrication is based on a simple drop-cast deposition of silver or gold nanomaterials on an aluminium foil support, making the design suitable for mass production.
The fabricated SERS substrates can withstand very high average Raman laser power of up to 400 mW in the NIR wavelength range while maintaining a linear signal response of the analyte.
This enables a combined high signal enhancement potential provided by:
(i) field enhancement via the localized surface plasmon resonance introduced by the noble metal nanomaterials, and
(ii) additional enhancement proportional to an increase of the applicable Raman laser power, without causing thermal decomposition of the analyte.
The application of the SERS substrates for trace detection of melamine and rhodamine 6G is demonstrated.
The results show limits of detection smaller than 0.1 ppm and analytical enhancement factors on the order of 10⁴ as compared to bare aluminium foil.