(229j) Fabrication of Graphene Quantum Dots (GQDs)

The unique structure of monolayered graphene was composed of a one-atom thick two-dimensional crystal of sp² carbon atoms arranged in a honeycomb lattice had been attributed to its extraordinary electronic properties such as high intrinsic mobility, and excellent thermal and electrical conductivity. Those characteristics of graphene had led to extensive applications in the fields of electronic devices, including photovoltaic cells, supercapacitors and flexible touch screens. In addition to the superlative electronic properties, recent studies have demonstrated the graphene’s photoluminescent (PL) characteristics, which could expand its application area in optical related fields. The PL property of graphene was derived by controlling the zero-band gap of graphene. Since the bandgap could be tuned by the size, shape, and fraction of the sp2 domains in the sp3 matrix, a variety of graphene derivatives were explored as PL graphene moieties.

We demonstrated one step way to fabricate two different sizes of graphene quantum dots (GQDs) through modified Hummers oxidation from graphene oxide, which had many advantages of simple, low cost, in larger scale with a high yield comparing to the previously reported methods. Several instruments were employed to characterize the composition and morphology of resultants. Bright blue luminescent from GQDs were obtained with a high yield of 34.8%. Moreover, the size of GQDs has affected the light wavelength and proposed mechanism will be discussed in detail during the meeting.  The discovery of the new PL from GQDs may expand the application of graphene-based materials to other fields such as optoelectronics and biological labeling.