Hidden Properties of Carbon Dots Revealed After HPLC Fractionation

Vinci, John C.; Ferrer, Ivonne M.; Seedhouse, Steven J.; Bourdon, Allen K.; Reynard, Justin M.; Foster, Barbara A.; Bright, Frank V.; Colón, Luis A.

doi:10.1021/jz301911y

Cited by 111 publications

(101 citation statements)

References 43 publications

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“…Using the nitric acid-sulfuric acid mixture, we found that, after 1 h of reaction, luminescent nanoparticle fractions were regenerated that had chromatographic patterns and elution times similar to those obtained from GNFs. 4 To investigate whether, indeed, different bulk carbon starting materials could be used to reproduce similar C-dots species, the oxidation of CFs was followed for seven days using AE-HPLC (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

“…9 Carbon dots have also been synthesized from CFs by electrochemical etching; 22 other reports of CF-derived CNPs use single-temperature and reaction-time conditions. 10 Although there is a plethora of literature on various reaction conditions at different temperatures and oxidizing conditions using nitric acid only, 3 nitric acidsulfuric acid mixtures, 4 and modified Hummers' methods, 5 there is a distinct lack of fundamental studies and understanding of the reaction dynamics and the species produced at various time points. Furthermore, a detailed study of intact CFs treated under a mixture of nitric and sulfuric acids has previously revealed that oxygen-, nitrogen-, and sulfur-containing groups varied discontinuously over time on the CF surface, especially in the early stages of reaction.…”

Section: Introductionmentioning

confidence: 99%

“…There are reports on using both CFs and GNFs to produces C-dots. 4,5,9,10 Considering their costs (GNFs cost $$50.00/g and CFs $$0.10/g), it is important to understand whether both can be used to generate the same species. We also wanted to understand how CNP species change over an extended period of time in the reaction vessel.…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic Characteristics of Carbon Dots (C-Dots) Derived from Carbon Fibers and Conversion to Sulfur-Bridged C-Dots Nanosheets

et al. 2015

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We synthesized sub-10 nm carbon nanoparticles (CNPs) consistent with photoluminescent carbon dots (C-dots) from carbon fiber starting material. The production of different C-dots fractions was monitored over seven days. During the course of the reaction, one fraction of C-dots species with relatively high photoluminescence was short-lived, emerging during the first hour of reaction but disappearing after one day of reaction. Isolation of this species during the first hour of the reaction was crucial to obtaining higherluminescent C-dots species. When the reaction proceeded for one week, the appearance of larger nanostructures was observed over time, with lateral dimensions approaching 200 nm. The experimental evidence suggests that these larger species are formed from small C-dot nanoparticles bridged together by sulfur-based moieties between the C-dot edge groups, as if the C-dots polymerized by cross-linking the edge groups through sulfur bridges. Their size can be tailored by controlling the reaction time. Our results highlight the variety of CNP products, from sub-10 nm C-dots to $200 nm sulfur-containing carbon nanostructures, that can be produced over time during the oxidation reaction of the graphenic starting material. Our work provides a clear understanding of when to stop the oxidation reaction during the top-down production of Cdots to obtain highly photoluminescent species or a target average particle size.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectroscopic Characteristics of Carbon Dots (C-Dots) Derived from Carbon Fibers and Conversion to Sulfur-Bridged C-Dots Nanosheets

et al. 2015

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“…Due to the intensive research efforts carried out in the past decades, the scientific community nowadays understands much better the structural, photophysical, and chemical properties of C-dots; however, the complete characterization of C-dots mixture still remains unachieved and faces noteworthy challenge. This is due to the fact that a C-dots product exists as a complex mixture comprising components with various sizes and different surface functionalities, and a polydisperse C-dots sample only represents the summation or average properties of all individual C-dots species [95,100,101]. In this sense, there is an urgent need for the development of efficient analytical separation methods to isolate high-purity C-dots fractions for more precious investigation of their unique chemical and photophysical properties.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Analytical Separation of Fluorescent Carbon Nanodots

Gong

Liu

et al. 2017

Journal of Nanomaterials

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Carbon nanodots (C-dots) are recently discovered fluorescent carbon nanoparticles with typical sizes of <10 nm. The C-dots have been reported to have excellent photophysical and chemical characteristics. In recent years, the advances in the development and improvement in C-dots synthesis, characterization, and applications are burgeoning. In this review, we introduce the most commonly used techniques for the characterization of C-dots. The characterization techniques for C-dots are briefly classified, described, and illustrated with applied examples. In addition, the analytical separation methods for C-dots (including electrophoresis, chromatography, density gradient centrifugation, differential centrifugation, solvent extraction, and dialysis) are included and discussed according to their analytical characteristics. The review concludes with an outlook towards the future developments in the characterization and the analytical separation of C-dots. The comprehensive overview of the characterization and the analytical separation techniques will safeguard people to use each technique more wisely.

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“…Unlike the semiconductor quantum dots derived from heavy metal precursors incurring long term toxicity [11], C-dots are environmentally friendly and lack of known cytotoxicity [12,13]. The spectroscopic studies have shown that the mixture of C-dots of different sizes with the ability to emit in different color at different excitation wavelength [14]. The multicolor property of C-dots has made them promising "nano-lights" that can emit tuneable photoluminescence for various applications.…”

Section: Introductionmentioning

confidence: 99%