Chapter 2 - Graphene quantum dots characterization and surface modification

Abstract

The zero-dimensional (0D) characteristics of graphene quantum dots (GQDs), mainly due to its outstanding properties, have caught the interest of many researchers. Numerous methods are used to synthesize GQDs. The significance of data collecting through the characterization of GQDs is essential to investigate the morphology, structural analysis, and properties, which is especially true in determining the potential of GQDs for specific applications, whether it is the functional groups attached or biocompatibility. As GQDs are a derivative of graphene, the same techniques used in the characterization of graphene can be exploited for GQDs. In this chapter, we will investigate multiple characterization procedure which can be divide into two categories: spectroscopy and microscopy, which include Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy transmission electron microscopy electron (TEM), Brunauer-Emmett-Teller thermogravimetric analysis X-ray photoelectron spectroscopy (XPS), and many more. Alternatively, surface chemistry studies have provided opportunities for many applications by altering the interaction of surfaces. GQDs possess limitations due to their heteroatoms or surface groups, which will hinder it from being used in some applications, ranging from field emission devices to biosensing applications. Therefore, some surface modifications can be applied to remove these obstacles, which we will discuss further in this chapter.