Preparation of graphene quantum dots through liquid phase exfoliation method

Zdražil, Lukáš; Zahradníček, Radim; Mohan, Rajneesh; Sedláček, Petr; Nejdl, Lukáš; Schmiedova, Veronika; Pospı́šil, J.; Horák, Michal; Weiter, Martin; Zmeškal, Oldřich; Hubálek, Jaromír

doi:10.1016/j.jlumin.2018.08.017

Cited by 25 publications

(17 citation statements)

References 31 publications

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“…By using various synthetic methods and tuning reaction conditions, the properties of the synthesized GQDs can be manipulated. Hydro-and solvothermal synthesis, [68,71,72] electrochemical exfoliation, [73] and liquid phase exfoliation [74,75] are some of the techniques employed as top-down methods.…”

Section: Top-down Methodsmentioning

confidence: 99%

“…[8] Copyright 2017, Elsevier. Graphite rods Electrochemical exfoliation 340 400 2.6 ± 0.4 Facile synthesis of GQDs [71] Graphite rods Electrochemical exfoliation 440-480 4 Tumor detection using pH-responsive change in PL [131] Graphite flakes Microwave-assisted liquid phase exfoliation 400-550 6 Synthesis without oxidation or reducing agents [75] Graphite Graphite intercalated method 400-550 5…”

Section: Physical Propertiesmentioning

confidence: 99%

“…Then, these expanded graphite flakes were dispersed in NMP and ultrasonicated for 9 h, after which GQDs were obtained by removing sediments via centrifugation. [75] In contrast to electrochemical exfoliation, LPE does not provide precise control over the morphology of the resulting GQDs because the cleavage of the bulk material occurs at the intercalation sites that are randomly dispersed within the lattice. However, the use of sonication instead of chemical oxidation and reduction as a means of synthesis demonstrates a safer and simpler alternative to other top-down methods.…”

Section: Liquid-phase Exfoliationmentioning

confidence: 99%

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Graphene Quantum Dots and Their Applications in Bioimaging, Biosensing, and Therapy

2019

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the bandgap of graphene may be tunably increased by decreasing the size of the graphene fragment. These graphene particles have been dubbed graphene quantum dots (GQDs), and this tunable electronic structure has been exploited for applications in electronics, energy harvesting, and medicine. [2] One of the most utilized properties of GQDs is their photoluminescence (PL), which describes the emission of light by graphene caused by the excitation of electrons within a GQD upon the absorption of incident photons and the subsequent emission of photons when those excited electrons relax back to a lower energy level. Through various studies, it has been shown that the PL excitation and emission wavelengths can be altered by controlling the size of GQDs, changing the surface properties, or through the introduction of dopants, such as nitrogen or boron, into the carbon lattice. [3][4][5] The tunable PL of GQDs makes them an effective platform for application in bioimaging and biosensing systems since the optimal wavelengths of light dictated by the situation at hand may be harnessed by synthesizing GQDs of appropriate size and/or dopant concentration to elicit the desired PL properties. In addition to dopants within the lattice, oxygen-rich functional groups such as hydroxyl and carboxyl groups exist on the edge of GQDs. These functional groups are a result of oxidation and self-passivation at the surface of GQDs during synthesis, and these polar constituents confer excellent aqueous solubility onto the GQDs, which is beneficial for biological applications. [6] Furthermore, functional groups allow for the facile surface conjugation of useful moieties such as tumor-targeting ligands or chemotherapeutics for use in anticancer drug delivery systems. [7][8][9][10] In many other nanoparticle-based drug delivery systems, a solid core is stabilized by coating the core with polymers, which restricts the number of sites available for chemotherapeutic conjugation on the surface of the nanoparticle. Conversely, GQDs have a large surface area to volume ratio, owing to their planar structure; this allows for higher drug loading and more efficient delivery of chemotherapeutics. Furthermore, π-orbitals that are present throughout the sp 2 -hybridized GQD lattice can bind chemotherapeutics that have an aromatic ring in their structure through π-stacking, without covalent conjugation, further enhancing their ability for drug delivery. [8,11,12] The potential for GQDs to make a substantial impact in medicine has been demonstrated by a myriad of recent developments. Many studies have been aimed at developing novel Graphene quantum dots (GQDs) are carbon-based, nanoscale particles that exhibit excellent chemical, physical, and biological properties that allow them to excel in a wide range of applications in nanomedicine. The unique electronic structure of GQDs confers functional attributes onto these nanomaterials such as strong and tunable photoluminescence for use in fluorescence bioimaging and biosensing, a high loading capacity of aroma...

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Section: Top-down Methodsmentioning

confidence: 99%

Section: Physical Propertiesmentioning

confidence: 99%

Section: Liquid-phase Exfoliationmentioning

confidence: 99%

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Graphene Quantum Dots and Their Applications in Bioimaging, Biosensing, and Therapy

2019

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“…To prepare GQDs, low and highly defected (edge and surface defects) precursors are graphite and acetylene carbon powder respectively has been used through this process. 56,57 Graphene was produced through LE of graphite aer intercalation by Viculis et al 58 and has involved great attention recently. Inspired by this, Sarkar et al 57 have synthesized GQDs through LE via probe sonication treatment of graphite powder.…”

Section: Synthesis Of Gqdsmentioning

confidence: 99%

Graphene quantum dot based materials for sensing, bio-imaging and energy storage applications: a review

et al. 2020

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“…However, LP is among the most promising method for synthesis of 2D nanosheets with unique benefits, such as low production costs, ease of operation, or minimal environmental impact. Furthermore, the graphite is exfoliated to graphene layers during the long LP phase and is mostly very thin (quantum size) with low-defect Nano graphite powder and highly defective acetylene carbon powder were prepared via LP [73].…”

Section: Electrochemical Methodsmentioning

confidence: 99%

Outstanding Graphene Quantum Dots from Carbon Source for Biomedical and Corrosion Inhibition Applications: A Review

et al. 2021

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Graphene quantum dots (GQD) is an efficient nanomaterial composed of one or more layers of graphene with unique properties that combine both graphene and carbon dots (CDs). It can be synthesized using carbon-rich materials as precursors, such as graphite, macromolecules polysaccharides, and fullerene. This contribution emphasizes the utilization of GQD-based materials in the fields of sensing, bioimaging, energy storage, and corrosion inhibitors. Inspired by these numerous applications, various synthetic approaches have been developed to design and fabricate GQD, particularly bottom-up and top-down processes. In this context, the prime goal of this review is to emphasize possible eco-friendly and sustainable methodologies that have been successfully employed in the fabrication of GQDs. Furthermore, the fundamental and experimental aspects associated with GQDs such as possible mechanisms, the impact of size, surface alteration, and doping with other elements, together with their technological and industrial applications have been envisaged. Till now, understanding simple photo luminance (PL) operations in GQDs is very critical as well as there are various methods derived from the optical properties of manufactured GQDs can differ. Lack of determining exact size and morphology is highly required without loss of their optical features. Finally, GQDs are promising candidates in the after-mentioned application fields.

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Preparation of graphene quantum dots through liquid phase exfoliation method

Cited by 25 publications

References 31 publications

Graphene Quantum Dots and Their Applications in Bioimaging, Biosensing, and Therapy

Graphene Quantum Dots and Their Applications in Bioimaging, Biosensing, and Therapy

Graphene quantum dot based materials for sensing, bio-imaging and energy storage applications: a review

Outstanding Graphene Quantum Dots from Carbon Source for Biomedical and Corrosion Inhibition Applications: A Review

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