On the Nature of Defects in Liquid-Phase Exfoliated Graphene

BRACAMONTE, M. V; GABRIELA LACCONI; SILVIA URRETA; LUIS E. F. FOA TORRES

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2014 vol. 118 p. 15455 - 15459

1932-7447

Liquid-phase exfoliation is one of the most promising routes for large-scale production of multilayer graphene dispersions. These  dispersions, which may be used in coatings, composites, or paints, are  believed to contain disorder-free graphene multilayers. Here, we address the  nature of defects in such samples obtained by liquid-phase exfoliation of graphite powder in N-methyl-2-pyrrolidone. Our Raman spectroscopy data  challenge the assumption that these multilayers are free of bulk defects,  revealing that defect localization strongly depends on the sonication time. For short ultrasound times, defects are located mainly at the layer edges; they turn  out to build up in the bulk for ultrasonic times above 2 h. This knowledge may  help to devise better strategies to achieve high-quality graphene dispersions.