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Advancement in liquid exfoliation of graphite through simultaneously oxidizing and ultrasonicating

journal contribution
posted on 21.12.2014, 00:00 authored by G Shi, A Michelmore, J Jin, Luhua LiLuhua Li, Ying (Ian) ChenYing (Ian) Chen, L Wang, H Yu, G Wallace, S Gambhir, S Zhu, P Hojati-Talemi, J Ma
Layered crystals, once exfoliated in liquids, create nanosheets with large surface area and likely generate electron band gaps. The current liquid exfoliation of graphite is performed by either oxidation, ultrasonication or the oxidation followed by ultrasonication; these methods are respectable but have limitations in general: the oxidation actually produces graphene oxide while the sonication is timeconsuming with a low yield. In this paper we report a highly effective yet simple approach for the fabrication of high-quality graphene; the approach consists of simultaneously oxidizing and ultrasonicating graphite for merely 60 min, followed by washing and filtration. Exfoliation was markedly promoted by the simultaneous treatment, where 80% of the sheets comprise single or few layers with lateral dimensions ranging 50 nm to over 100 nm; their carbon to oxygen ratio is at 8.85; the ratio of Raman D- to G-band intensity is as low as 0.211; and the sheets can be stably dispersed in acetone for at least 48 hours and they have an electrical conductivity over 600 S cm-1. A thin graphene film made by casting exhibited a sheet resistance of ∼1000 Ωsquare-1 with 80% transparency at 550 nm.

History

Journal

Journal of Materials Chemistry A

Volume

2

Issue

47

Pagination

20382 - 20392

Publisher

Royal Society of Chemistry

Location

Cambridge, England

ISSN

2050-7488

eISSN

2050-7496

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2014, Royal Society of Chemistry