Sensitive Surface-Enhanced Raman Scattering Detection Using On-Demand Postassembled Particle-on-Film Structure

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) requires highly sensitive and low-cost substrates for practical applications.
• Conventional SERS substrates often involve pre-treatment for analyte absorption, limiting flexibility.

Purpose of the Study:

• To develop a simple, cost-effective, and highly sensitive SERS substrate using a novel sandwich configuration.
• To demonstrate the substrate's efficacy in detecting low concentrations of molecules, including pesticide residues.

Main Methods:

• Fabrication of a particle/molecule/film sandwich structure by postassembling a plasmonic nanoparticle-embedded gel tape onto an analyte-decorated gold film.
• Utilizing the analyte molecules as both spacers and signal probes within the hot spots formed at the particle-film interface.
• Evaluating SERS detection sensitivity down to 10^-10 M.

Main Results:

• The assembled sandwich structure exhibits strong SERS signals due to numerous hot spots at the particle-film interface.
• The proposed SERS substrate demonstrates high sensitivity, achieving molecular detection limits as low as 10^-10 M.
• The substrate can be produced over large areas at extremely low cost.

Conclusions:

• The postassembly strategy offers an on-demand and flexible approach for SERS substrate fabrication.
• This method provides an ideal solution for sensitive detection of pesticide residues on fruit surfaces.
• The developed SERS substrate significantly enhances detection sensitivity and reduces costs for practical applications.