Rationally Designed Graphene/Bilayer Silver/Cu Hybrid Structure with Improved Sensitivity and Stability for Highly...

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Surface-enhanced Raman scattering (SERS) requires efficient substrates for trace molecule detection.
• Existing SERS substrates often face challenges with sensitivity, durability, and cost-effectiveness.

Purpose of the Study:

• To design and fabricate a novel, cost-effective SERS substrate with enhanced sensitivity and stability.
• To investigate the SERS performance of a graphene/bilayer silver/copper sandwich structure for detecting trace pollutants.

Main Methods:

• Fabrication of a sandwich structure using graphene, bilayer silver (silver dendrites on silver nanospheres), and a copper plate.
• Growth of silver dendrite nanostructures on a silver nanosphere/copper surface.
• Characterization of SERS performance using portable Raman spectroscopy with crystal violet and rhodamine 6G as target molecules.

Main Results:

• The fabricated bilayer silver/copper structure showed a 1.5-fold Raman enhancement over the silver nanosphere/copper substrate.
• The optimized graphene/bilayer silver/copper sandwich structure exhibited high sensitivity with limits of detection of 10^-9 M for crystal violet and 10^-8 M for rhodamine 6G.
• The substrate demonstrated excellent reproducibility (RSD < 5.9%) and long-term stability (peak intensity deviation < 3.6% over 25 days) due to graphene's protective effect.

Conclusions:

• The graphene/bilayer silver/copper sandwich structure serves as a highly efficient and stable SERS substrate.
• This novel substrate shows significant potential for the reliable, quantitative detection of environmental pollutants.