277483 Monodisperse Carbon Nanotubes Produced Using Iterative Orthogonal Density Gradient Ultracentrifugation

Tuesday, October 30, 2012: 12:30 PM
311 (Convention Center )
Alexander A. Green, Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA and Mark C. Hersam, Northwestern University, Evanston, IL

The variation in physical and electronic properties of as-synthesized carbon nanotubes can hinder their application as optical, electronic, and energy harvesting materials. Here, we describe the use of iterative orthogonal density gradient ultracentrifugation (DGU) to isolate carbon nanotubes that are monodisperse in physical structure and electronic properties. This approach achieves concurrent separation by electronic type (semiconducting or metallic) and diameter, thus enabling the production of highly pure semiconducting single-walled carbon nanotubes (SWNTs) in which 99% of the nanotubes have diameters within 0.01 nm of each other. Applying this strategy to a polydisperse mixture of multi-walled carbon nanotubes, we demonstrate the enrichment of double-walled carbon nanotubes (DWNTs) having outer walls of either semiconducting or metallic electronic type. The semiconducting character of these sorted carbon nanotubes is verified through direct electrical measurements in carbon nanotube network thin film transistors (TFTs). TFTs fabricated from semiconducting outer wall DWNTs provide on/off ratios two orders of magnitude higher than comparable metallic DWNT devices. Furthermore, semiconducting SWNT devices exhibit on/off ratios approaching 105 and mobilities up to 37 cm2V-1s-1, while maintaining on-state width-normalized conductances of 0.19 S/m. These figures of merit suggest future application of these monodipserse SWNTs in integrated circuits and near-infrared optoelectronic light emitters and photodetectors.

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See more of this Session: Graphene and Carbon Nanotubes: Applications
See more of this Group/Topical: Nanoscale Science and Engineering Forum