Vibrational Analysis of Organic Molecules Encapsulated in Carbon Nanotubes by Tip-Enhanced Raman Spectroscopy
Abstract
Tip-enhanced Raman spectroscopy revealed the nanoscale chemical properties of organic molecules encapsulated in single-wall carbon nanotubes (SWNTs). Our approach is based on an enhanced electric field near a laser-irradiated metal tip functioning as a Raman excitation source. The enhanced field can successfully act on encapsulated molecules through the walls of the SWNTs to extract molecular vibrational information. β-carotene, which exhibits several active Raman modes under visible light illumination, was used as the encapsulated molecule. Tip-enhanced Raman spectra measured at seven different positions on SWNT bundles showed that β-carotene molecules inside the tubes were not uniformly distributed. We also found that the filling rate and peak position of the radial breathing mode of the SWNTs are linearly correlated.
- Publication:
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Japanese Journal of Applied Physics
- Pub Date:
- December 2006
- DOI:
- 10.1143/JJAP.45.9286
- Bibcode:
- 2006JaJAP..45.9286S