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Surface enhanced Raman spectroscopy: new materials, concepts, characterization tools, and applications
Jon A Dieringer1, Adam D McFarland, Nilam C Shah
1Department of Chemistry, Northwestern University, Evanston IL 60208-3113, USA.
Faraday Discussions
|July 13, 2006
Summary
Researchers developed robust surface-enhanced Raman spectroscopy (SERS) substrates using nanosphere lithography and atomic layer deposition. This advancement enables highly sensitive molecular detection and in vivo glucose sensing.
Area of Science:
- Plasmonics and Nanophotonics
- Spectroscopy
- Materials Science
Background:
- Surface-enhanced Raman spectroscopy (SERS) relies on localized surface plasmon resonance (LSPR) for signal amplification.
- Controlling factors like material, size, shape, and environment is crucial for reproducible SERS.
- Nanotechnology offers pathways to engineer SERS substrates with enhanced performance.
Purpose of the Study:
- To fabricate reproducible and robust SERS substrates for fundamental studies and applications.
- To investigate the impact of dielectric environment and interparticle spacing on SERS using novel fabrication techniques.
- To explore advanced SERS techniques like tip-enhanced Raman spectroscopy (TERS) and in vivo sensing.
Main Methods:
- Nanosphere lithography (NSL) for fabricating SERS substrates.
- Atomic layer deposition (ALD) for creating dielectric spacers and controlling the nanoscale environment.
- Wavelength scanned SER excitation spectroscopy (WS SERES) for characterizing enhancement factors.
- 2D correlation analysis for single molecule SERS (SMSERS) data.
- In vivo SERS glucose sensing.
Main Results:
- NSL-fabricated surfaces achieve enhancement factors of approximately 10^8.
- ALD enables precise control over dielectric environments and distance dependence studies.
- WS SERES provides insights into electromagnetic field enhancement mechanisms.
- TERS shows promise for improving SERS generality and information content.
- Demonstrated the first in vivo SERS glucose sensing study.
Conclusions:
- Nanosphere lithography and ALD are effective methods for creating high-performance, reproducible SERS substrates.
- Precise control over substrate parameters significantly enhances SERS capabilities.
- Advanced techniques like TERS and in vivo sensing expand the applicability of SERS.
- This work paves the way for sensitive molecular detection and real-time biological monitoring.