Long-term effects of impurities on the particle size and optical emission of carbon dots

Javed, Nasir; O’Carroll, Deirdre M.

doi:10.1039/d0na00479k

Cited by 33 publications

(27 citation statements)

References 48 publications

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“…[142] They also observed the gradual growth of non-dialyzed CDs upon storage over 13 weeks concomitantly with their quantum yield plummeting from 30 % to 3 %, against no growth at all for dialyzed-CDs. [142] Yellow PL is attributed to CDs surface states while blue PL is attributed to free molecular fluorophores capable of aggregating themselves around CDs upon storage.…”

Section: The Molecular Questionmentioning

confidence: 91%

“…To illustrate the criticalness of purification, N. Javed and D. M. O'Carroll reported a single blue PL band for their non‐dialyzed CDs, and both blue and yellow bands for dialyzed ones [142] . They also observed the gradual growth of non‐dialyzed CDs upon storage over 13 weeks concomitantly with their quantum yield plummeting from 30 % to 3 %, against no growth at all for dialyzed‐CDs [142] . Yellow PL is attributed to CDs surface states while blue PL is attributed to free molecular fluorophores capable of aggregating themselves around CDs upon storage.…”

Section: Carbon Dots Terminologymentioning

confidence: 99%

See 1 more Smart Citation

Carbon Dots for Carbon Dummies: The Quantum and The Molecular Questions Among Some Others

Boëver

Town

et al. 2022

Chemistry A European J

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Carbon Dots (CDs) are carbon nanoparticles which were discovered in 2004. Despite two decades of intensive work from the scientific community and a colossal amount of gathered experimental data, no definitive consensus exists to date on several key aspects such as the actual definition of CDs and the origin of their emissive properties. This review proposes a critical evaluation of these fundamental questions. Lay persons will also find here an alternative introduction to the CDs domain, including synthetic strategies, photophysical properties, as well as challenges and outlook of this exciting new area.

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Section: The Molecular Questionmentioning

confidence: 91%

Section: Carbon Dots Terminologymentioning

confidence: 99%

Carbon Dots for Carbon Dummies: The Quantum and The Molecular Questions Among Some Others

Boëver

Town

et al. 2022

Chemistry A European J

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“…To identify the material luminescence properties like photoluminescence, chemiluminescence, and phosphorescence, the lifetime measurements are performed using PL lifetime spectroscopy ( Sun et al., 2020 ). The first approximation for the particle size measurements have been achieved using dynamic light scattering ( Javed and O’Carroll, 2021 ) based particle size analyzers, where the Brownian motion of the nanoparticles scatters the laser light and the analysis of the fluctuations is interpreted. Surface charge of the carbon dots has been obtained from zeta potential studies.…”

Section: Characterizationmentioning

confidence: 99%

Heavy metal ion detection using green precursor derived carbon dots

Torres¹,

Bogireddy

Kaur

et al. 2022

iScience

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“…Furthermore, we have recently shown that if CDs are not properly purified, their photoluminescence QY can considerably decrease even when they are stored in the dark. [77] More reports about the photostability of CDs are summarized in Table 1. It is noted that in almost all studies that report significant photobleaching, CDs were derived from bottomup approaches.…”

Section: Photobleachingmentioning

confidence: 99%

“…Furthermore, we have recently shown that if CDs are not properly purified, their photoluminescence QY can considerably decrease even when they are stored in the dark. [ 77 ]…”

Section: Stabilitymentioning

confidence: 99%

Carbon Dots and Stability of Their Optical Properties

Javed

O’Carroll

2021

Part & Part Syst Charact

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exploited for fabrication of light-emitting devices, [5] and their remarkable electronic properties have been used in the fields of photovoltaics [6] and electronics. [5d,7] Low toxicity and the excellent biocompatibility of CDs encourage researchers to study the role of CDs in the biomedical field, and many bioimaging [8] and drug delivery [9] applications of CDs have been reported. The dependence of the optical properties of CDs on the presence of metal ions in dispersion has been exploited for cation detection applications. [10] Besides this, CDs have been demonstrated to be useful for energy storage, [11] photocatalysis, [12] electrochemical sensing, [13] electrochemiluminescence sensing, [13,14] sensing and killing microorganisms [15] including viruses, [16] and numerous other applications. Although there have been several lab-scale demonstrations of a variety of different applications of CDs, there are hardly any commercially available device based on CDs. [3] To commercialize CD-based devices/applications, stable and predictable PL emission is one of the most important requirements. In a few early studies of the properties of CDs, it was reported that the PL emission of CDs is photostable, that is, CDs are photostable. [17] Additionally, the PL quantum yield (QY) of CDs reported in early studies was very low, typically less than 10%, and emission was mostly understood to arise from the presence of surface functional groups. In recent years, due to improvements in synthesis methods and use of different raw materials, remarkable increases in the PL QY of CDs have been reported. [18] Often the bright PL emission from these CDs is comparable to that of molecular fluorophores. Molecule-like bright emission from CDs is often attributed to the presence of molecular fluorophores on the surface of CDs [19] or sometimes freely floating in dispersion due to poor purification. [20] This striking change in the optical properties gave rise to observations of other molecular features in CDs, like blinking and photobleaching.Despite hundreds of published studies exploring the synthesis, properties and application of CDs, there are relatively few reports that consider the photostability of CDs. Most reports that showed CDs to be photostable were carried out in the early years of the development of CDs, and, consequently, CDs are still considered to be photostable. However, there are also some more recent reports showing significant photobleaching of CDs. Here, we review published work on the photostability of CDs. It is noted that while there is a wide variation in the reported photostability of CDs, there is also a lack of homogeneous systematic studies. In most studies of photobleaching the geometry of the experiment (i.e., the Carbon dots (CDs) are a new class of materials which have been extensively studied due to their unique optical properties, low toxicity, and abundance of raw materials to synthesize them. In this minireview, it is highlighted that the stability of the optical properties of CDs is an important...

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Long-term effects of impurities on the particle size and optical emission of carbon dots

Abstract: Carbon dots (CDs) are fluorescent nanoparticles that exhibit strong photoluminescence (PL) emission throughout the visible range of the electromagnetic spectrum. Recent studies highlight the presence of fluorescent impurities in CDs...

Cited by 33 publications

References 48 publications

Carbon Dots for Carbon Dummies: The Quantum and The Molecular Questions Among Some Others

Carbon Dots for Carbon Dummies: The Quantum and The Molecular Questions Among Some Others

Heavy metal ion detection using green precursor derived carbon dots

Carbon Dots and Stability of Their Optical Properties

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