Nanoscale chemical imaging of solid-liquid interfaces using tip-enhanced Raman spectroscopy
Naresh Kumar1, Weitao Su, Martin Veselý
1National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK. andy.wain@npl.co.uk.
Nanoscale
|January 9, 2018
Summary
Researchers developed new Tip-Enhanced Raman Spectroscopy (TERS) probes for nanoscale chemical imaging in liquids. These robust probes enable high-resolution surface mapping in aqueous environments, overcoming previous limitations.
Area of Science:
- Surface science
- Nanotechnology
- Spectroscopy
Background:
- Tip-Enhanced Raman Spectroscopy (TERS) offers nanoscale chemical imaging but is limited in liquid environments.
- Existing TERS probes lack stability and robustness when immersed in liquids, hindering applications.
Purpose of the Study:
- To develop stable, plasmonically-active TERS probes for nanoscale chemical imaging in liquid environments.
- To investigate the impact of liquid environments on TERS signal enhancement and understand signal attenuation mechanisms.
Main Methods:
- Fabrication of multilayer metal-coated TERS probes designed for liquid immersion.
- Comparative analysis of plasmonic enhancement in air versus water for gap and non-gap modes.
- Numerical simulations to correlate electric field enhancement with the refractive index of the surrounding medium.
Main Results:
- Novel TERS probes demonstrate stability and functionality in aqueous environments.
- Plasmonic enhancement of TERS signals decreases in water compared to air for both configurations.
- Simulations confirm a negative correlation between probe-apex electric field enhancement and medium refractive index.
Conclusions:
- The developed TERS probes enable the first demonstration of nanoscale spatial resolution chemical imaging in water.
- These robust probes significantly broaden the applicability of TERS to solid-liquid interface studies across various scientific disciplines.
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