Synthesis, Applications, and Prospects of Graphene Quantum Dots: A Comprehensive Review

Abstract

Graphene quantum dot (GQD) is one of the youngest superstars of the carbon family. Since its emergence in 2008, GQD has attracted a great deal of attention due to its unique optoelectrical properties. Non‐zero bandgap, the ability to accommodate functional groups and dopants, excellent dispersibility, highly tunable properties, and biocompatibility are among the most important characteristics of GQDs. To date, GQDs have displayed significant momentum in numerous fields such as energy devices, catalysis, sensing, photodynamic and photothermal therapy, drug delivery, and bioimaging. As this field is rapidly evolving, there is a strong need to identify the emerging challenges of GQDs in recent advances, mainly because some novel applications and numerous innovations on the ease of synthesis of GQDs are not systematically reviewed in earlier studies. This feature article provides a comparative and balanced discussion of recent advances in synthesis, properties, and applications of GQDs. Besides, current challenges and future prospects of these emerging carbon‐based nanomaterials are also highlighted. The outlook provided in this review points out that the future of GQD research is boundless, particularly if upcoming studies focus on the ease of purification and eco‐friendly synthesis along with improving the photoluminescence quantum yield and production yield of GQDs.

Carbon Dots in Bioimaging, Biosensing and Therapeutics: A Comprehensive Review

“…[183][184][185] Most of the CDs@drug complexes have cleavable chemical bonds, allowing the targeted release of drugs under the acidic environment of tumor sites or in response to other stimuli. [186][187][188] In addition to enhancing the delivery and controlled release at the target site, CDs can help overcome the drug resistance of cancer cells or other diseased cells.…”

Structured Ultra‐Flyweight Aerogels by Interfacial Complexation: Self‐Assembly Enabling Multiscale Designs

“…Like graphene, graphene oxide (GO) nanosheets are essentially one-atom thick but can be as wide as tens of micrometers (Figure S1, Supporting Information). [32][33][34] Recently, it was shown [35] that GO nanosheets in water (W-GO, see Table 1 for abbreviations) instantaneously migrate and assemble at the oil/ water (O/W) interface due to their tendency to spread over highenergy interfaces, to minimize the Helmholtz free energy. [32,36] This propensity stems from the dual nature (hydrophobic and hydrophilic) of GO; the hydrophobic nature of GO nanosheets originates from the basal plane, i.e., carbon rings.…”

Graphene Quantum-Dot-Based Nanophotonic Approach for Targeted Detection of Long Noncoding RNAs in Circulation

“… 4 − 6 In comparison to QDs and other metallic NPs, GQDs offer steady fluorescence properties, improved biocompatibility, and minimal toxicity and thus are considered superior for various biological applications. 7 , 8 The other remarkable optoelectric features of GQDs, such as the excitation-dependent photoluminescence emission, transfer and redox of photo-induced electrons, and size-tunable optical characteristics, further allow flexibility in the selection of the desired wavelength with minimal spectral overlapping. This has also widened the use of these NPs for various multiplexed, highthroughput diagnostic applications.…”