Improved stabilities on surface-enhanced Raman scattering-active Ag/Al2O3 films on substrates

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Surface-enhanced Raman scattering (SERS)-active silver (Ag) films are widely used for analyte structure examination.
• Ag nanoparticles (NPs) offer significant SERS effects but suffer from stability issues.
• Improving the stability of SERS-active materials is crucial for practical applications.

Purpose of the Study:

• To develop more stable SERS-active Ag films.
• To investigate the effect of incorporating Al2O3 NPs on the stability of Ag films.
• To evaluate the thermal and environmental stability of the novel Ag/Al2O3 films.

Main Methods:

• Preparation of Ag/Al2O3 colloids using sonoelectrochemical methods in nitric acid solution.
• Fabrication of SERS-active Ag/Al2O3 films on glass slides via salting-out with saturated NaCl solution.
• Characterization of film stability under elevated temperatures and controlled humidity conditions.

Main Results:

• Ag/Al2O3 films demonstrated significantly improved thermal stability, withstanding operation temperatures over 100 °C.
• The incorporation of Al2O3 NPs suppressed the aging of SERS enhancement capability under 50% relative humidity and 20% O2 at 30 °C.
• A minor decrease in Raman intensity (approx. 30%) was observed compared to pure Ag films.

Conclusions:

• Ag/Al2O3 composite films offer enhanced thermal and environmental stability for SERS applications.
• The improved stability comes at an acceptable cost of reduced Raman intensity.
• These findings pave the way for more robust SERS-based analytical techniques.