Design of Carbon Dots for Metal-free Photoredox Catalysis

Cailotto, Simone; Mazzaro, Raffaello; Enrichi, Francesco; Vomiero, Alberto; Selva, Maurizio; Cattaruzza, Elti; Cristofori, Davide; Amadio, Emanuele; Perosa, Alvise

doi:10.1021/acsami.8b14188

Cited by 85 publications

(70 citation statements)

References 56 publications

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“…It can be noticed that different carbonizing agents applied for the glucose carbonization ( Table 2) caused diversification in their size and shape. However, their round-shaped morphology is typical for CQDs obtained by the bottom-up approach and corresponds to other researchers' results [36][37][38][39]44]. It can be observed that the Dot-3 sample prepared using tartaric acid is the most uniform one and the average carbon dot diameter is 10 nm.…”

Section: Scheme 1 Carbon Quantum Dots With the Free Carboxylic Groupsupporting

confidence: 87%

“…Molecules 2020, 25, combining with other types of nanoparticles [21,[36][37][38][39]. Application of heteroatoms, such as nitrogen and sulfur, helps to create new surface states which results in enhanced photoluminescence (PL) properties, especially increased photostability and quantum yield [10,24,35].…”

Section: Fouriertransform Infrared Spectroscopy (Ftir) and Nuclear Mamentioning

confidence: 99%

“…Similar functionalization of the carbon quantum dots was carried out using hyaluronic acid which enabled controlled doxorubicine delivery coupled with realtime bioimaging [24]. Aforementioned examples show that novel approaches of carbon quantum dot functionalization are highly desired since, although there are still many issues to be overcome, CQDbased nanomaterials may play a crucial role in the development of nanomedicine [2,[36][37][38][39]. The aim of the following research was to develop a new type of carbon quantum dots functionalized with novel rhodamine derivatives to enhance their PL.…”

Section: Fouriertransform Infrared Spectroscopy (Ftir) and Nuclear Mamentioning

confidence: 99%

“…Molecules 2020, 25, x FOR PEER REVIEW 8 of 18 are two strong absorption peaks present in the diluted CQD solutions, one sharp and one broad. The first one, around 200 nm, comes from the π → π* transitions of C=C groups which are caused by the sp2 hybridization of the C atoms [2], whereas the peaks at 293 nm (Dot-2), 298 nm (Dot-3), 301 nm (Dot-1), and 301 nm (Dot-4) corresponds to n → π* transitions of C=O groups [2,38,39,43]. The UV-VIS spectrum is typical for carbon quantum dots and two different surface states can be distinguished which agrees with the data obtained by other researchers [2,6,8,43].…”

Section: Spectroscopic Properties Studymentioning

confidence: 99%

“…Neutral or negatively-charged macromolecules are used for the CQDs' surface modification with therapeutic designation since they prevent protein adsorption, resulting in prolonged circulation in blood [24]. There are also numerous scientific reports regarding other ways of carbon quantum dot functionalization, including doping and combining with other types of nanoparticles [21,[36][37][38][39]. Application of heteroatoms, such as nitrogen and sulfur, helps to create new surface states which results in enhanced photoluminescence (PL) properties, especially Sample Availability: Samples of the compounds are available from the authors on the request.…”

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confidence: 99%

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Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

et al. 2020

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Carbon quantum dots (CQDs) are nanoobjects of a size below 10 nm. Due to their favorable features, such as tunable luminescence, unique optical properties, water solubility, and lack of cytotoxicity, they are willingly applied in biomedicine. They can be obtained via bottom-up and top-down methods. However, to increase their quantum yield they must undergo post-processing. The aim of the following research was to obtain a new type of CQDs modified with a rhodamine b derivative to enhance their fluorescence performance without biocompability deterioration. For their preparation glucose was used as a precursor and four different carbonizing agents which affected semi-and final products luminescence properties. The ready nanomaterials were investigated over their chemical structure by FTIR and NMR, whereas morphology was investigated by the TEM method. Their optical properties were determined by UV-VIS spectroscopy. Fluorescence behavior, photo-and pH-stability, as well as solvatochromism showed their applicability in various biomedical applications due to the controlled properties. The samples exhibited excellent antioxidant activity and lack of cytotoxicity on L929 mouse fibroblasts. The results showed that proposed strategy enables preparation of the superior nanomaterials with outstanding luminescence properties such as quantum yield up to 17% which can be successfully applied in cell labelling, bioimaging, and theranostics.Molecules 2020, 25, 736 2 of 18 can release cadmium ions leading to cell death. Importantly, it occurred that quantum dots may undergo certain modifications resulting in the change of their surface or chemical structure [27,28]. Finally, their preparation is expensive. Therefore, there was a need for a novel type of quantum dots which would be suitable for biomedical applications. In 2004, a new type of carbon-based materials was accidentally obtained during nanotube purification [29]. Until then, numerous types of carbon quantum dots (CQDs) have been obtained with various possible applications due to their very attractive properties, such as luminesce, good water solubility, high photostability, resistance to photobleaching or photoblinking, possibility, chemical inertness and, finally, lack of toxicity and biocompability [1][2][3]. Furthermore, CQDs' region of photoluminescence is very broad, starting in the ultraviolet and ending in the near-infrared. Although, until now, the luminescence behavior of carbon nanodots is still not fully clear, it is believed that crucial role plays two factors, namely, that the quantum size is below 10 nm and surface defects which may act as excitation energy traps. Interestingly, CQDs can successfully act as both electron donors and acceptors [2][3][4].CQDs can be prepared from various resources, such as peels (mango, orange, banana, pineapple, onion, seaweed etc.), meat, grains, nuts, or vegetable by-products, which makes them a low-cost material [30,31]. Currently, these nanomaterials are widely applied in drug delivery, gene delivery, biosensing, bioimag...

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Section: Scheme 1 Carbon Quantum Dots With the Free Carboxylic Groupsupporting

confidence: 87%

Section: Fouriertransform Infrared Spectroscopy (Ftir) and Nuclear Mamentioning

confidence: 99%

Section: Fouriertransform Infrared Spectroscopy (Ftir) and Nuclear Mamentioning

confidence: 99%

Section: Spectroscopic Properties Studymentioning

confidence: 99%

mentioning

confidence: 99%

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Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

et al. 2020

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Influence of Electron Acceptor and Electron Donor on the Photophysical Properties of Carbon Dots: A Comparative Investigation at the Bulk‐State and Single‐Particle Level

Srivastava

Khamo

Pandit

et al. 2019

Adv Funct Materials

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Carbon dots (CDs) are extensively studied to investigate their unique optical properties such as undergoing electron transfer in different scenarios. This study presents an in-depth investigation to study the ensemble-averaged state/bulk state and single-particle level photophysical properties of CDs that have been passivated with electron-accepting (CD-A) and electron-donating molecules (CD-D) on their surface. Our ensemble-averaged state experiments including UV-Vis absorbance titrations, time-resolved photoluminescence (PL) spectra, and 2D emission studies depicted that both CD-A or CD-D had a blue-shift in emission, with a drastic increase in emission intensity, and consequently higher quantum yields, and that acceptor populations (CD-A) dominate overall photophysical properties. Interestingly, transmission electron microscopy and atomic force microscopy revealed that the mixing of donor and acceptor particles (CD-A+ CD-D) leads to a formation of at least two associated geometries, which was dependent on time, concentration, intramolecular electron/charge transfer and hydrogen bonding. On the other hand, single-particle studies revealed that the instantaneous intensity of CDs was comparable, but that CD-A and CD-D have a larger on-time duty cycle, attributed to an increase of blinking frequency. On-and off-time power-law analysis further revealed that CD-A has a larger off-time distribution slope than bare CDs, This article is protected by copyright. All rights reserved. 3 while their on-time distribution is similar. CD-D exhibits an increase in both on-and off-time distribution slope compared to bare CDs. These results indicate that the electron donor provides additional bright and dark states, while the electron acceptor primarily provides bright states, which can explain the increased blinking frequency in CD-A and CD-D at the single-particle level. Singleparticle studies, however, did not reveal an "acceptor-dominating" scenario based on analysis of instantaneous intensity, bleaching kinetics, and photoblinking, indicating that the direct interaction of CD-A and CD-D may affect their photophysical properties in the bulk state due to formation of hierarchical structural assemblies. We anticipate that these fundamental results will further provide insights towards our understanding of the complex mechanism associated with CD emission, which is one of the key contributors to their successful application. As an immediate application of these CDs, we have shown that they can be used as a sensing array for metal ions and can serve as a powerful toolbox for the technological application of CDs.

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Carbon Dots for Photocatalytic Degradation of Aqueous Pollutants: Recent Advancements

Akbar

Moretti

Vomiero

2021

Advanced Optical Materials

Self Cite

102

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The immense progress of humanity on the technological, domestic, and industrial fronts comes at the cost of polluting the planet. Aquatic pollution is particularly dangerous since all life forms are directly linked to it. Each year tons of industrial and domestic pollutants make their way into aqueous systems. Efficient removal/degradation of these pollutants is of prime importance for the sustainable future. Among many technologies, photodegradation is an emerging and promising method for the successful removal of aqueous pollutants since it is powered by abundant solar light. The last decade had shown that carbon dots are among the most promising materials that can be utilized as an efficient tool to derive various solar‐driven chemical reactions. Carbon dots possess unique photophysical and chemical properties such as light‐harvesting over a broad‐spectrum region, upconversion photoluminescence, photosensitizers, chemical inertness, and bivalent redox character, etc. The ease of synthesis of carbon dots at low cost also contributes hugely to their utilizations as an efficient photocatalyst for the degradation of aqueous pollutants. This review summarizes the recent progress made in the field of photodegradation of aqueous pollutants with the aid of carbon dots and their hybrids, highlighting the critical role carbon dots can play in the field.

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Design of Carbon Dots for Metal-free Photoredox Catalysis

Cited by 85 publications

References 56 publications

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

Influence of Electron Acceptor and Electron Donor on the Photophysical Properties of Carbon Dots: A Comparative Investigation at the Bulk‐State and Single‐Particle Level

Carbon Dots for Photocatalytic Degradation of Aqueous Pollutants: Recent Advancements

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