A Practical Guide to Prepare and Synthetically Modify Graphene Quantum Dots

Due to the favorable properties of graphene quantum dots (GQDs), there has been a rapid development of sensors, devices, and composite materials, which incorporate this 0D nanomaterial. GQDs provide a means to instill superior optical, electronic, mechanical, and adsorptive properties to various platforms and have found use as biosensors, photovoltaic devices, polymer composites, and drug delivery vehicles. One of the key factors to successfully integrating GQD technology is the intelligent choice of synthetic chemical pathways to fabricate, modify, and instill functionality in the developed platform. GQDs are decorated with a variety of functional groups that are amenable to traditional synthetic chemistry transformations; however, the technology for post-synthetic modifications is only in its infancy. Herein, a comprehensive analysis of the chemistry available for modifying GQDs is provided; starting from methods for GQD fabrication and synthetic chemical pathways for producing functional GQDs, to the advantages, disadvantages, and challenges of specific chemistries, and finally techniques for the appropriate characterization of these functional materials. This review is meant for researchers considering entering the GQD field, as well as those more experienced, providing a practical guide on how to prepare, modify, and characterize GQDs for a broad range of applications.