High-quality thin graphene films from fast electrochemical exfoliation

Ching Yuan Su, Ang-Yu Lu, Yanping Xu, Fu Rong Chen, Andrei N. Khlobystov, Lain Jong Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

880 Scopus citations

Abstract

Flexible and ultratransparent conductors based on graphene sheets have been considered as one promising candidate for replacing currently used indium tin oxide films that are unlikely to satisfy future needs due to their increasing cost and losses in conductivity on bending. Here we demonstrate a simple and fast electrochemical method to exfoliate graphite into thin graphene sheets, mainly AB-stacked bilayered graphene with a large lateral size (several to several tens of micrometers). The electrical properties of these exfoliated sheets are readily superior to commonly used reduced graphene oxide, which preparation typically requires many steps including oxidation of graphite and high temperature reduction. These graphene sheets dissolve in dimethyl formamide (DMF), and they can self-aggregate at air-DMF interfaces after adding water as an antisolvent due to their strong surface hydrophobicity. Interestingly, the continuous films obtained exhibit ultratransparency (∼96% transmittance), and their sheet resistance is <1k σ/sq after a simple HNO3 treatment, superior to those based on reduced graphene oxide or graphene sheets by other exfoliation methods. Raman and STM characterizations corroborate that the graphene sheets exfoliated by our electrochemical method preserve the intrinsic structure of graphene.

Original languageEnglish (US)
Pages (from-to)2332-2339
Number of pages8
JournalACS Nano
Volume5
Issue number3
DOIs
StatePublished - Mar 22 2011
Externally publishedYes

Keywords

  • Raman spectroscopy
  • electrochemical exfoliation
  • field-effect transistor
  • graphene
  • transparent conductive film

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy

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