Long-Life and pH-Stable SnO₂-Coated Au Nanoparticles for SHINERS

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Shell-isolated nanoparticles (SHINs) are crucial for enhancing Raman spectroscopy signals.
• Conventional silica (SiO2)-coated SHINs face limitations in durability and pH stability.
• Developing robust SHINs is essential for broader applications in harsh chemical environments.

Purpose of the Study:

• To investigate tin dioxide (SnO2)-coated gold nanoparticles (Au-SnO2) as a more durable alternative to SiO2-coated SHINs.
• To evaluate the long-term Raman enhancement stability and pH resistance of Au-SnO2 SHINs.
• To demonstrate the utility of Au-SnO2 SHINs in Shell-Isolated Nanoparticles for Enhanced Raman Spectroscopy (SHINERS).

Main Methods:

• Synthesis of Au-SnO2 core-shell nanoparticles with controlled dimensions (37 nm Au core, 11 nm SnO2 shell).
• Evaluation of Raman enhancement performance over an extended period (3 months).
• Assessment of nanoparticle stability across a broad pH range (pH 2-13).

Main Results:

• Au-SnO2 SHINs demonstrated sustained Raman enhancement for up to 3 months.
• The SnO2 coating provided excellent stability in highly acidic (pH 2) and alkaline (pH 13) conditions.
• Compared to SiO2-coated SHINs, Au-SnO2 exhibited significantly improved durability and wider pH tolerance.

Conclusions:

• Tin dioxide is a superior coating material for developing durable Shell-Isolated Nanoparticles.
• Au-SnO2 SHINs offer enhanced longevity and chemical robustness for SHINERS applications.
• These findings pave the way for utilizing SHINERS in more challenging analytical scenarios.