Monodisperse Chemically Modified Graphene Obtained by Density Gradient Ultracentrifugal Rate Separation

A simple density gradient ultracentrifuge separation method has been developed for sorting chemically modified graphene (CMG) by sheet size and surface chemistry in just a few minutes. By optimizing the parameters, including the density gradient and centrifugation time, CMG sheets with specific size ranges and optical properties can be targeted selectively. UV−vis absorbance and photoluminescence spectra revealed the properties of separated CMG samples are highly dependent on their sheet size and degree of oxidation. A possible mechanism for the separation is discussed.