Synthesis, Characterization and Applications of Graphene Quantum Dots

Abstract

Graphene quantum dots (GQDs) represent unique zero-dimensional (0D) carbon materials with the lateral size below 100 nm. It possesses similar characteristics to graphene including large surface area, high electronic mobility, non-toxicity and chemical stability. Moreover, its special nanoscale structure exhibits new phenomena due to quantum confinement and edge effects that give its distinct chemical, optical and physical properties, commonly nonzero bandgap and photoluminescence. The tunable properties by sizes and functional groups make the GQDs potential materials for various applications in recent years. In this chapter, we will discuss the synthesis, characterization and applications of GQDs. In general, there are two approaches for GQD synthesis including top-down preparation and bottom-up methods. Possible characterization techniques include spectroscopic methods such as absorbance, Raman, photoluminescence, infrared and X-ray photoelectron spectroscopies to analyze their electron states, fluorescence properties, functional group compositions and vibrational patterns, and microscopic methods such as transmission electron microcopy (TEM) and atomic force microscopy (AFM) to study their surface morphologies and crystalline structures. We will further discuss the potential applications of GQDs in the fields of biomedicine, biosensing, optoelectronics, and energy conversion and storage.