Folding and cracking of graphene oxide sheets upon deposition

Deepak K. Pandey, Birck Nanotechnology Center, Purdue University
Ting Fung Chung, Birck Nanotechnology Center, Purdue University
G. Prakash, Birck Nanotechnology Center, Purdue University
R. Piner, University of Texas at Austin
Yong P. Chen, Birck Nanotechnology Center, Purdue University
R. Reifenberger, Birck Nanotechnology Center, Purdue University

Abstract

Graphene Oxide (GO) sheets, suspended in an aqueous solution, were deposited on freshly cleaved highly oriented pyrolytic graphite (HOPG) and studied using Raman spectroscopy, atomic force microscopy (AFM) and scanning tunneling microscopy (STM). AFM phase imaging shows a distinct contrast between GO and the underlying HOPG substrate. Raman spectroscopy clearly showed the presence of GO sheets on the top of HOPG substrate. The AFM and STM images also reveal wrinkling, folding, and tearing of individual GO sheets after depositing onto an HOPG substrate. We have also observed a distinct cracking of a GO sheet after folding. We attribute this new cracking phenomenon to a weakening of C C bonds during the oxidation of a graphene sheet. (C) 2011 Elsevier B.V. All rights reserved.

Discipline(s)

Nanoscience and Nanotechnology