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Optical Trapping of Plasmonic Nanoparticles for In Situ Surface-Enhanced Raman Spectroscopy Characterizations
Published on: June 23, 2022
Enhancing single-nanoparticle surface-chemistry by plasmonic overheating in an optical trap
Weihai Ni1, Haojin Ba1, Andrey A Lutich1
1Photonics and Optoelectronics Group, Department of Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich, Germany.
Nano Letters
|August 29, 2012
Summary
Plasmonic overheating of gold nanorods in optical traps alters their surface chemistry. Unlike bulk experiments, localized heating enables unique red shifts, indicating increased aspect ratios due to solvent boiling.
Area of Science:
- Nanotechnology
- Physical Chemistry
- Surface Science
Background:
- Plasmonic nanoparticles exhibit unique optical properties.
- Optical trapping allows manipulation of individual nanoparticles.
- Plasmonic heating can modify nanoparticle properties.
Purpose of the Study:
- Investigate the surface chemistry of optically trapped plasmonic nanoparticles.
- Understand the effect of plasmonic overheating on nanoparticle behavior.
- Explain observed shifts in plasmon resonance.
Main Methods:
- Optical trapping of individual gold nanorods.
- Monitoring plasmon resonance shifts under varying optical power.
- Computational modeling to determine local temperatures.
Main Results:
- Plasmonic overheating significantly modifies nanoparticle surface chemistry.
- Gold nanorods showed red shifts (increasing aspect ratio) in optical traps under oxidative conditions.
- Calculations indicated local temperatures exceeding solvent boiling point in the trap.
Conclusions:
- Localized heating in optical traps drives unique nanoparticle transformations.
- Solvent boiling at the nanoscale is a key factor in observed red shifts.
- Findings differ from bulk experiments, highlighting the importance of localized effects.
