Solution Phase Processing of Carbon Nanotubes with Optoelectronic Tweezers

Carbon nanotube (CNT) processing will require a massively parallel technique to enable high-throughput patterning and separations. Optoelectronic tweezers (OET) have emerged in recent years as a powerful tool for highly parallel manipulation of micron scale particles, including solid-state nanowires [1]. In this presentation we demonstrate that aqueous dispersions of both carboxylic-functionalized and individual sodium dodecyl benzene sulfonate (SDBS) coated multiwalled CNTs are addressable with forces generated by optoelectronic tweezers (OET). Due to the large aspect ratio of carbon nanotubes, OET is capable of transporting CNTs in solutions with conductivites ranging from 10 – 100 mS/m while using 100,000x less optical power density than optical tweezers. AFM images are used to characterize nanotube diameters and in situ Raman spectroscopy is presented as a way to monitor nanotube ensembles trapped within individual OET potential wells. Digital video microscopy is used to quantify inter-tube repulsion dynamics resulting from dipole-dipole interactions. Potential applications involving nanotube separations and optically-patterned nanotube arrays will be discussed.

References:

[1] Jamshidi, A.; Pauzauskie, P. J.; Schuck, P. J.; Ohta, A. T.; Chiou, P. Y.; Chou, J.; Yang, P. D.; Wu, M. C. Nature Photonics 2008, 2, 85-89.