Tunable excitation-independent emissions from graphene quantum dots through microplasma-assisted electrochemical synthesis

Joffrion, Joshua B.; Clower, William; Wilson, Curtis M.

doi:10.1016/j.nanoso.2019.100341

Cited by 22 publications

(10 citation statements)

References 38 publications

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“…Therefore, it is suggested that the present GQDs prepared via microwave irradiation do not have considerable emissive traps or defect states and exhibit PL due to single emission fluorescence centre 64 , 66 . Since the prepared GQDs displays this unique optical characteristic, this makes them ideal for numerous applications such as lasing, display technologies, multi-target bioimaging and encryption 68 .…”

Section: Resultsmentioning

confidence: 99%

High yield synthesis of graphene quantum dots from biomass waste as a highly selective probe for Fe3+ sensing

Abbas

Tabish

Bull

et al. 2020

Sci Rep

168

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Graphene quantum dots (GQDs), a novel type of zero-dimensional fluorescent materials, have gained considerable attention owing to their unique optical properties, size and quantum confinement. However, their high cost and low yield remain open challenges for practical applications. In this work, a low cost, green and renewable biomass resource is utilised for the high yield synthesis of GQDs via microwave treatment. The synthesis approach involves oxidative cutting of short range ordered carbon derived from pyrolysis of biomass waste. The GQDs are successfully synthesised with a high yield of over 84%, the highest value reported to date for biomass derived GQDs. As prepared GQDs are highly hydrophilic and exhibit unique excitation independent photoluminescence emission, attributed to their single-emission fluorescence centre. As prepared GQDs are further modified by simple hydrothermal treatment and exhibit pronounced optical properties with a high quantum yield of 0.23. These modified GQDs are used for the highly selective and sensitive sensing of ferric ions (Fe3+). A sensitive sensor is prepared for the selective detection of Fe3+ ions with a detection limit of as low as 2.5 × 10–6 M. The utilisation of renewable resource along with facile microwave treatment paves the way to sustainable, high yield and cost-effective synthesis of GQDs for practical applications.

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Section: Resultsmentioning

confidence: 99%

High yield synthesis of graphene quantum dots from biomass waste as a highly selective probe for Fe3+ sensing

Abbas

Tabish

Bull

et al. 2020

Sci Rep

168

View full text Add to dashboard Cite

show abstract

“…Quantum confinement effect, size of the zigzag, recombination of the localized electron/hole pairs, surface states, and sites of defects, all play a part in making the emission spectra of carbon-based quantum dots unique to their corresponding composition and functionalities. The first three elements, which are termed intrinsic state emission, cause excitation-independent emission spectra in carbon-based quantum dots, whereas differing surface states and defect sites cause excitation wavelength-dependent emission spectra. , Figure b,c shows the PL emission spectra of G1 and G2, respectively. The sp 2 carbon domains with fewer defects display an emission spectrum that is independent of the excitation wavelength.…”

Section: Results and Discussionmentioning

confidence: 99%

Biological Evaluation of Graphene Quantum Dots and Nitrogen-Doped Graphene Quantum Dots as Neurotrophic Agents

Raghavan,

Radhakrishnan,

Soren

et al. 2023

ACS Appl. Bio Mater.

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Over time, developments in nano-biomedical research have led to the creation of a number of systems to cure serious illnesses. Tandem use of nano-theragnostics such as diagnostic and therapeutic approaches tailored to the individual disease treatment is crucial for further development in the field of biomedical advancements. Graphene has garnered attention in the recent times as a potential nanomaterial for tissue engineering and regenerative medicines owing to its biocompatibility among the several other unique properties it possesses. The zero-dimensional graphene quantum dots (GQDs) and their nitrogen-doped variant, nitrogen-doped GQDs (N-GQDs), have good biocompatibility, and optical and physicochemical properties. GQDs have been extensively researched owing to several factors such as their size, surface charge, and interactions with other molecules found in biological media. This work briefly elucidates the potential of electroactive GQDs as well as N-GQDs as neurotrophic agents. In vitro investigations employing the N2A cell line were used to evaluate the effectiveness of GQDs and N-GQDs as neurotrophic agents, wherein basic investigations such as SRB assay and neurite outgrowth assay were performed. The results inferred from immunohistochemistry followed by confocal imaging studies as well as quantitative real-time PCR (qPCR) studies corroborated those obtained from neurite outgrowth assay. We have also conducted a preliminary investigation of the pattern of gene expression for neurotrophic and gliotrophic growth factors using ex vivo neuronal and mixed glial cultures taken from the brains of postnatal day 2 mice pups. Overall, the studies indicated that GQDs and N-GQDs hold prospect as a framework for further development of neuroactive compounds for relevant central nervous system (CNS) purposes.

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“…An aqueous solution of NaOH is prepared as an electrolyte through the GQDs synthesis process. Then, the graphite rod and platinum foil, which acted as both the anode and counter electrode were soaked in an aqueous solution and applying the 5.0 v voltage for 6 h. The color of the homogeneous solution was changed from brownish to dark black along the reaction time and by filtration, GQDs were eventually obtained [71]. The GQDs synthesis by the electrochemical oxidation procedure has good stability, but perhaps the pre-treatment of raw materials and the cleansing of GQDs take a very long time, and the quantum yield is considerably low, making it difficult to achieve large-scale production of GQDs [72].…”

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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Tunable excitation-independent emissions from graphene quantum dots through microplasma-assisted electrochemical synthesis

Cited by 22 publications

References 38 publications

High yield synthesis of graphene quantum dots from biomass waste as a highly selective probe for Fe3+ sensing

High yield synthesis of graphene quantum dots from biomass waste as a highly selective probe for Fe3+ sensing

Biological Evaluation of Graphene Quantum Dots and Nitrogen-Doped Graphene Quantum Dots as Neurotrophic Agents

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

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