Properties and Synthesis Strategies of Graphene Quantum Dots

Abstract

Quantum dots (QDs) are usually referred to as semiconductor nanoparticles with their sizes in the quantum-confined regime, in which the excitons are confined in all the three spatial dimensions. Typical QDs are inorganic semiconductor nanocrystals from the group II-VI elements in the periodic table. However, the applications of these QDs are limited by their internal disadvantages, including intrinsic toxicity (e.g. in the case of widely studied CdSe QDs) and problems caused by the colloidal stability. Therefore, developing new QDs and relevant nanomaterials is necessary. Consequently, graphene quantum dots (GQDs), a class of zero-dimensional (0D) graphitic nanomaterials, have attracted increasing attention recently. Compared with semiconductor QDs, GQDs are superior in terms of low cytotoxicity, high dispersity in water and some polarity organic solvents, resistance to photobleaching and biocompatibility. In addition, the properties of GQDs are easier to be tuned through surface chemistry, indicating that researchers can design GQDs with various functionalities for different applications.