Nature Commun. 5, 3186 (2014)

With a tensile strength of over 100 GPa, a pristine graphene layer is the strongest material known. However, most graphene fabrication processes inevitably produce a defective layer. Also, structural defects are desirable in some of the material's technological applications, as defects allow for the opening of a bandgap or act as pores for molecular sieving, for example. Now, by tuning the exposure of graphene to oxygen plasma to control the creation of defects, Ardavan Zandiatashbar et al. show that a single layer of graphene bearing sp3-type defects (chemisorbed oxygen atoms) at a high density (an average spacing between defects of 5 nm) maintains its stiffness, and that its breaking strength is only reduced by 14%. Instead, the presence of vacancies (formed by the removal of carbon atoms at higher oxygen-plasma exposure) causes both mechanical properties to degrade significantly from those of the pristine layer. The researchers also show that Raman spectra can be mapped to the measured stiffness and strength, thereby providing a non-destructive method to predict these properties from the respective Raman parameters.