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Advances in OptoElectronics
Volume 2012 (2012), Article ID 869829, 4 pages
Research Article

In Situ Raman Spectroscopy of COOH-Functionalized SWCNTs Trapped with Optoelectronic Tweezers

1Chemical Sciences Division, Lawrence Livermore National Laboratory, 7000 East Avenue L-231, Livermore, CA 94551, USA
2Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
3Department of Electrical Engineering, University of California, Berkeley, CA 94720, USA

Received 2 May 2011; Revised 2 November 2011; Accepted 16 November 2011

Academic Editor: Eric Pei Yu Chiou

Copyright © 2012 Peter J. Pauzauskie et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Optoelectronic tweezers (OETs) were used to trap and deposit aqueous dispersions of carboxylic-acid-functionalized single-walled carbon nanotube bundles. Dark-field video microscopy was used to visualize the dynamics of the bundles both with and without virtual electrodes, showing rapid accumulation of carbon nanotubes when optical virtual electrodes are actuated. Raman microscopy was used to probe SWCNT materials following deposition onto metallic fiducial markers as well as during trapping. The local carbon nanotube concentration was observed to increase rapidly during trapping by more than an order of magnitude in less than one second due to localized optical dielectrophoresis forces. This combination of enrichment and spectroscopy with a single laser spot suggests a broad range of applications in physical, chemical, and biological sciences.