High-concentration solvent exfoliation of graphene

Umar Khan, Arlene O'Neill, Mustafa Lotya, Sukanta De, Jonathan N. Coleman

Research output: Contribution to journalArticlepeer-review

921 Citations (Scopus)

Abstract

A method is demonstrated to prepare graphene dispersions at high concentrations, up to 1.2mg mL-1, with yields of up to 4 wt% monolayers. This process relies on low-power sonication for long times, up to 460 h. Transmission electron microscopy shows the sonication to reduce the flake size, with flake dimensions scaling as t-1/2. However, the mean flake length remains above 1 μm for all sonication times studied. Raman spectroscopy shows defects are introduced by the sonication process. However, detailed analysis suggests that predominately edge, rather than basal-plane, defects are introduced. These dispersions are used to prepare high-quality freestanding graphene films. The dispersions can be heavily diluted by water without sedimentation or aggregation. This method facilitates graphene processing for a range of applications.

Original languageEnglish
Pages (from-to)864-871
Number of pages8
JournalSmall
Volume6
Issue number7
DOIs
Publication statusPublished - 9 Apr 2010
Externally publishedYes

Keywords

  • Films
  • Graphene dispersions
  • Solvent exfoliation

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