Density Gradient Ultracentrifugation of Graphene


22 Φεβ 2014 (πριν από 3 χρόνια και 4 μήνες)

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Gradient Ultracentrifugation
of Graphene

Nano Letters
, 4931 (2009).

Alexander Green and Mark Hersam

National Science Foundation
Nanoelectronics Research Initiative Grant DMR

NRI supplement to IRG
4 of the Northwestern University
MRSEC is developing unique
combinations of materials,
prototype devices, and
experimental tools to study
excitons in carbon
nanomaterials. The program aims

to explore, understand, and optimize the electrial generation of excitons, their stability,
transport, and exciton
exciton interactions in monodisperse carbon nanotubes and
graphene. One major thrust requires the isolation of monodisperse graphene flakes.
This is accomplished in solution using density gradient ultracentrifugation. Stable
graphene dispersions are produced using the bile salt sodium cholate, which promotes
graphite exfoliation and results in graphene
surfactant complexes having buoyant
densities that vary with graphene thickness. Graphene dispersions produced using
density differentiation offer superior performance in transparent conductors to those
produced using conventional sedimentation
based centrifugation techniques.