Synthesis and applications of graphene quantum dots: a review

Abstract

As a new class of fluorescent carbon materials, graphene quantum dots (GQDs) have attracted tremendous attention due to their outstanding properties and potential applications in biological, optoelectronic, and energy-related fields. Herein, top-down and bottom-up strategies for the fabrication of GQDs, mainly containing oxidative cleavage, the hydrothermal or solvothermal method, the ultrasonic-assisted or microwave-assisted process, electrochemical oxidation, controllable synthesis, and carbonization from small molecules or polymers, are discussed. Different methods are presented in order to study their characteristics and their influence on the final properties of the GQDs. The respective advantages and disadvantages of the methods are introduced. With regard to some important or novel methods, the mechanisms are proposed for reference. Moreover, recent exciting progresses on the applications of GQD, such as sensors, bio-imaging, drug carriers, and solar cells are highlighted. Finally, a brief outlook is given, pointing out the issues still to be settled for further development. We believe that new preparation methods and properties of GQDs will be found, and GQDs will play more important roles in novel devices and various applications.

Applications of Graphene Quantum Dots in Biomedical Sensors

“…Among these, semiconductor QDs were so far preferred as ideal fluorescent probes owing to their narrow range of emission, broad excitation wavelength, good photo-stability and easy functionalization ability with surface reagents. Nonetheless, most of the semiconductor QDs (i.e., PbS, CdTeSe@CdZnS, CdTe@CdSe and CdHgTe) comprise heavy metals, resulting into unfavorable environmental and biological detrimental effects, which obstruct their biomedical applicability [63][64][65]. However, GQDs being a member of the carbon family have emerged as novel carbon-based fluorescent materials, due to their excellent biocompatibility, fluorescence property and non-toxicity.…”

Carbon-based quantum particles: an electroanalytical and biomedical perspective

“…A review by Shen et al 31 captures much of the current progress and the excitement, while the synthetic methods for the formation of GQDs have been reviewed recently in Ref. 32 Here we give a global overview of methods applicable to the formation of carbon-based quantum particles without differentiation between CQDs and GQDs. Independent of the carbon nanostructure aimed at, the synthetic approaches are generally classified into two main categories: top-down and bottom up.…”

A brief review for fluorinated carbon: synthesis, properties and applications

“…The synthesis methods of fluorinated carbon can be mainly classified into direct gas fluorination, indirect fluorination and plasma-assisted fluorination [12][13][14]. The C-F bonds and the F/C ratios deeply depend on the raw carbon materials and fluorination conditions including fluorinating agents, temperature and reaction time [15][16][17]. Thus, the key point of fluorinated carbon materials is mainly about the design of carbon materials and the optimization of fluoridation conditions.…”