Toward a reusable surface-enhanced Raman spectroscopy (SERS) substrate by soft-landing ion mobility

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) requires precisely controlled nanostructures for optimal sensitivity.
• Developing reusable SERS substrates is crucial for cost-effective and sustainable analytical applications.
• Traditional methods for nanoparticle deposition can be complex and may not yield uniform feature sizes.

Purpose of the Study:

• To develop a reusable SERS substrate using soft-landing ion mobility (SLIM) for gold nanoparticle deposition.
• To optimize gold deposition parameters for enhanced Raman scattering.
• To demonstrate the substrate's reusability and specificity in detecting analytes.

Main Methods:

• Silicon wafer substrates were modified with 3-(mercaptopropyl) triethoxysilane.
• Gold nanoparticles were deposited onto the modified silicon wafers using SLIM at controlled thermal kinetic energies.
• Deposition time (30 min) and pressure were optimized for feature size and surface coverage.
• Caffeine was used as an analyte to test Raman activity and substrate performance.
• The substrate was cleaned and re-tested with sodium bicarbonate to assess reusability and absence of cross-contamination.

Main Results:

• Optimal feature size for SERS was achieved with 30 minutes of gold deposition.
• Raman signal intensity of caffeine showed an inverse relationship with deposition pressure, correlating with gold particle coverage.
• The developed substrate demonstrated high sensitivity for caffeine detection.
• Ultrasonic cleaning in deionized water effectively removed residual caffeine, allowing for successful detection of sodium bicarbonate without interference.

Conclusions:

• Soft-landing ion mobility is an effective technique for fabricating reusable SERS substrates with controlled gold nanoparticle morphology.
• The optimized deposition process yields a highly sensitive and specific platform for molecular detection.
• The demonstrated reusability and lack of cross-contamination highlight the practical utility of this SERS substrate in analytical chemistry.