ABSTRACT
Graphene quantum dots (GQDs) are single-up to five-layer formations of limited size, mostly 3 to 20 nm, fragments or pieces of graphene [1]. The presence of a graphene structure inside the dots not only endows them with some of the unusual properties of graphene but quantum confinement and edge effects resulting from converting two-dimensional graphene to zero-dimensional quantum dots yield novel electronic and optical properties [2-5]. These graphene-based carbon nanomaterials were first synthesized by Pan et al. in 2010 in order to exploit the optical properties that are directly associated with the quantum confinement and edge effects, and they obtained the first fluorescent GQDs about 9.6 nm in diameter [2]. The functionalized GQDs exhibited bright blue photoluminescence, which had never been observed in graphene sheets and graphene nanoribbons owing to their large lateral sizes.
