Graphitic Dots Combining Photophysical Characteristics of Organic Molecular Fluorophores and Inorganic Quantum Dots

Boëver, Raphaël de; Langlois, Adam; Xu, Liang; Claverie, Jérôme P.

doi:10.1021/jacsau.1c00055

Cited by 17 publications

(25 citation statements)

References 29 publications

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“…Although CDs have already permeated many different fields, it is apparent that any application will encounter the challenge of expanding knowledge on the structure-activity relationship of CDs. Further development in controlled synthesis, along with development of innovative methods, 172 will surely lead to rapid progression and new unforeseen applications. There is great scope and potential for absolute control over function and application in bottom-up approach.…”

Section: Perspectivesmentioning

confidence: 99%

A multifunctional chemical toolbox to engineer carbon dots for biomedical and energy applications

et al. 2022

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Photoluminescent carbon nanomaterials, or carbon dots (CDs), are an emerging class of materials that has recently attracted considerable attention for biomedical and energy applications. They are defined by characteristic sizes of <10 nm, a carbon-based core, and the possibility to add various functional groups at their surface for targeted applications. These nanomaterials possess many interesting physicochemical and optical properties, including tuneable light emission, dispersibility and low toxicity. In this Review, we categorize how chemical tools impact the properties of CDs. We look for pre-and post-synthetic approaches for the preparation of CDs and their derivatives or composites. We then showcase examples to correlate structure, composition, and function and use them to discuss the future development for this class of nanomaterials. monomer/polymer as starting materials. Historically, the top-down strategy was first exploited and consisted mainly of electrochemical or chemical oxidation of graphite. 7 While these approaches can yield relatively large quantities of CDs, they usually employ harsh conditions (in terms of voltage applied or chemical oxidant used), long synthetic times, and still need post-synthetic procedures to tune the optoelectronic properties. From the fluorescence perspective, oxidative cutting of carbon sources leads to more structural defects, resulting in less appealing photoluminescence properties.Currently, the bottom-up syntheses are more popular and will be the focus of this Review. In addition to the multitude of molecular precursors available, other benefits include multiple choices of thermal treatments, quicker reaction times, and more uniform properties in the final material. The choice of precursors and synthetic procedures (i.e. pre-synthetic control) affects the physicochemical properties of CDs in terms of size, graphitization degree, surface functional groups, and doping. Nevertheless, the structural features of the precursors can be retained in the nanoparticles, allowing for some degree of predictability. Single-component, to a certain extent, and multi-component reactions enable the use of straightforward doping strategies. These include heteroatoms (examples here include boron, nitrogen, sulfur, selenium, or a combination of them) and metals (such as lanthanides).Besides pre-synthetic control, engineering the surface composition via post-synthetic approaches is a promising way to optimize and expand the utilization of CDs (Fig. 1b). Post-synthetic strategies usually affect the surface functional groups of the CDs since they are generally inefficient in changing properties and chemical composition of the core. Exploiting their surface chemistry also prompted the development of multifunctional CD-based materials (Fig. 1c).There are many excellent sources of information about the intricacies of CDs properties [7][8][9][10][11] and their applications, [12][13][14][15][16] as well as their progress in comparison to traditional inorganic quantum dots. 17 At first, emphas...

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Section: Perspectivesmentioning

confidence: 99%

A multifunctional chemical toolbox to engineer carbon dots for biomedical and energy applications

et al. 2022

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“…Indeed, a protective effect of the carbon core against PB effects was already proposed in previous studies of the PB of specific blue-emitting fluorophores. 67 , 68 Anyway, the present FLIP experiments provide an efficient way to discriminate apparently identical CDs with respect to their photostability, which is an important functional property and is essential for viability in practical applications.…”

Section: Resultsmentioning

confidence: 99%

Photobleaching and Recovery Kinetics of a Palette of Carbon Nanodots Probed by In Situ Optical Spectroscopy

Terracina

Armano

Meloni

et al. 2022

ACS Appl. Mater. Interfaces

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Carbon dots (CDs) are a family of fluorescent nanoparticles displaying a wide range of interesting properties, which make them attractive for potential applications in different fields like bioimaging, photocatalysis, and many others. However, despite many years of dedicated studies, wide variations exist in the literature concerning the reported photostability of CDs, and even the photoluminescence mechanism is still unclear. Furthermore, an increasing number of recent studies have highlighted the photobleaching (PB) of CDs under intense UV or visible light beams. PB phenomena need to be fully addressed to optimize practical uses of CDs and can also provide information on the fundamental mechanism underlying their fluorescence. Moreover, the lack of systematic studies comparing several types of CDs displaying different fluorescence properties represents another gap in the literature. In this study, we explored the optical properties of a full palette of CDs displaying a range from blue to red emissions, synthesized using different routes and varying precursors. We investigated the photostability of different CDs by observing in situ their time-resolved fluorescence degradation or optical absorption changes under equivalent experimental conditions and laser irradiation. The results about different PB kinetics clearly indicate that even CDs showing comparable emission properties may exhibit radically different resistances to PB, suggesting systematic connections between the resistance to PB, the characteristic spectral range of emission, and CD quantum yields. To exploit the PB dynamics as a powerful tool to investigate CD photophysics, we also carried out dedicated experiments in a partial illumination geometry, allowing us to analyze the recovery of the fluorescence due to diffusion. Based on the experimental results, we conclude that the nature of the CD fluorescence cannot be solely ascribable to small optically active molecules free diffusing in solution, contributing to shed light on one of the most debated issues in the photophysics of CDs.

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“…Solvents such as dimethylformamide (DMF) and tetrahydrofuran (THF) were purchased from Sigma Aldrich (Burlington, MA, USA) and used without any further purification. The GDs were prepared using the method reported in [ 26 , 27 ].…”

Section: Methodsmentioning

confidence: 99%

Ultra-High Tg Thermoset Fibers Obtained by Electrospinning of Functional Polynorbornenes

et al. 2022

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Insertion polynorbornenes (PBNEs) are rigid-rod polymers that have very high glass transition temperatures (Tg). In this study, two functional PNBEs were electrospun in the presence of a variety of cross-linkers, resulting in fibers with Tgs greater than 300 °C. The fibers are long (several mm), rigid, and with diameters that can be tuned in the range 300 nm–10 μm. The electrospinning process can be used to encapsulate dyes or graphene dots. Due to the high cross-linking density of the fiber, dye leaching is prevented. In contrast with other rigid-rod polymers, electrospinning of PNBE is facile and can be performed at injection rates as high as 1 mL/min.

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Graphitic Dots Combining Photophysical Characteristics of Organic Molecular Fluorophores and Inorganic Quantum Dots

Cited by 17 publications

References 29 publications

A multifunctional chemical toolbox to engineer carbon dots for biomedical and energy applications

A multifunctional chemical toolbox to engineer carbon dots for biomedical and energy applications

Photobleaching and Recovery Kinetics of a Palette of Carbon Nanodots Probed by In Situ Optical Spectroscopy

Ultra-High Tg Thermoset Fibers Obtained by Electrospinning of Functional Polynorbornenes

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