Efficient one-pot synthesis of highly monodisperse carbon quantum dots

Linehan, Keith; Doyle, Hugh

doi:10.1039/c3ra45083j

Cited by 38 publications

(27 citation statements)

References 25 publications

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“…We have recently demonstrated that similar sized CQDs exhibit distinctly different absorbance and photoluminescence spectra when capped with ligands of different polarity, underlining the importance of the surface in determining their photophysical properties. 7,26 Due to the high degree of monodispersity within those samples, we concluded the most plausible explanation was that the excitation wavelength dependence observed originated from recombination of photogenerated excitons at different surface trap states. Since the surface of the CQDs were capped using the same ligand functionalisation method, any variation in the PL spectra shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Size controlled synthesis of carbon quantum dots using hydride reducing agents

Linehan

Doyle

2014

J. Mater. Chem. C

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Highly luminescent carbon quantum dots (CQDs) are synthesized at room temperature by hydride reduction of carbon tetrachloride (CCl4) within inverse micelles. Regulation of the average diameter of the allylamine terminated CQDs is achieved by varying the strength of the reducing agent used. Transmission electron microscopy shows that the NCs are highly crystalline with well-defined core diameters tuned from 2 to 6 nm, while FTIR and XPS spectroscopy confirm that the CQDs possess similar surface chemistry. UV-Vis and PL spectroscopy show significant quantum confinement effects, with moderate absorption in the UV spectral range, and a strong, narrow luminescence in the visible with a marked dependency on excitation wavelength. Time resolved photoluminescence measurements showed lifetimes for all CQDs in the ns range, while a maximum PL quantum yield of 27% is observed for the CQDs

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Section: Resultsmentioning

confidence: 99%

“…25 The size of the CQDs was controlled by regulating the amount of the emulsifier. Previously, we reported the synthesis of size monodisperse CQDs using a room temperature microemulsion strategy, 7,26 see Fig. 1.…”

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Size controlled synthesis of carbon quantum dots using hydride reducing agents

Linehan

Doyle

2014

J. Mater. Chem. C

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“…One widespread problem in CDs nanoscience is the heterogeneity of most CD samples, in the sense that several synthesis routes tend to yield CDs with a large degree of structural heterogeneity, such as very broad size distributions, large dot-to-dot variations in surface structure, optical heterogeneity, or the contamination of the sample by small fluorescent molecules produced together with CDs. Therefore, aside a few exceptions [84], the use of a purification method is often crucial to achieve a full control on the size dispersion of the synthesized nanosystems, or select some sub-sets of CDs based on their size or their surface structure. In some cases, separation methods have been used simply to select the most fluorescent part of a CD sample, out of a heterogeneous distribution of fluorescent quantum yields [10,85], leading to some of the highest fluorescence quantum yields reported in the literature.…”

Section: Purification and Separation Methodsmentioning

confidence: 99%

Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response

2018

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Carbon dots (CDs) are an emerging family of nanosystems displaying a range of fascinating properties. Broadly speaking, they can be described as small, surface-functionalized carbonaceous nanoparticles characterized by an intense and tunable fluorescence, a marked sensitivity to the environment and a range of interesting photochemical properties. CDs are currently the subject of very intense research, motivated by their possible applications in many fields, including bioimaging, solar energy harvesting, nanosensing, light-emitting devices and photocatalyis. This review covers the latest advancements in the field of CDs, with a focus on the fundamental understanding of their key photophysical behaviour, which is still very debated. The photoluminescence mechanism, the origin of their peculiar fluorescence tunability, and their photo-chemical interactions with coupled systems are discussed in light of the latest developments in the field, such as the most recent results obtained by femtosecond time-resolved experiments, which have led to important steps forward in the fundamental understanding of CDs. The optical response of CDs appears to stem from a very complex interplay between the electronic states related to the core structure and those introduced by surface functionalization. In addition, the structure of CD energy levels and the electronic dynamics triggered by photo-excitation finely depend on the microscopic structure of any specific sub-type of CD. On the other hand, this remarkable variability makes CDs extremely versatile, a key benefit in view of their very wide range of applications.

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“…For example, Kwon and Rhee used reverse micelles as nanoreactors to synthesize luminescent nanoparticles under the reaction temperature of 160 °C . Linehan and Doyle fabricated fluorescent nanoparticles through the metal reduction of carbon precursors in reverse micellar nanoreactors . However, most micellar nanoreactor approaches for PCPNs preparation require high temperature and involve the addition of toxic organic solvents or metal catalysts and the use of more than one chemical.…”

Section: Introductionmentioning

confidence: 99%

“…[19] Linehan and Doyle fabricated fluorescent nanoparticles through the metal reduction of carbon precursors in reverse micellar nanoreactors. [20] However, most micellar nanoreactor approaches for PCPNs preparation require high temperature and involve the addition of toxic organic solvents or metal catalysts and the use of more than one chemical. Therefore, the fabrication of PCPNs using vesicles as nanoreactors under ambient temperature and without a catalyst is crucial for scientific research and industry.…”

Section: Introductionmentioning

confidence: 99%

In Situ Nanoreactors: Controllable Photoluminescent Carbon‐Rich Polymer Nanodots Derived from Fatty Acid under Photoirradiation

Dai

Zhao

Fan

et al. 2018

Macromol. Rapid Commun.

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Amphiphilic nanoreactors have been recently used to fabricate photoluminescent carbon-rich polymer nanodots (PCPNs). However, the applications of PCPNs have been limited by their requirements for high temperature and toxic organic solvents or catalysts and the difficult control of their luminescent properties. Herein, a novel and facile strategy is reported for the synthesis of controllable PCPNs. This strategy involves the use of in situ vesicular nanoreactors under mild photoirradiation with fatty acid as the precursor. The conjugation degree of the uniformly sized PCPNs can be increased by extending photoreaction time, thus enabling the tuning of the optical properties of PCPNs. The PCPNs, which feature controllable and outstanding luminescent properties, low cytotoxicity, and biocompatibility, are successfully applied in bioimaging and as fluorescent ink. The present strategy is an attractive and facile platform for the preparation of carbon-rich nanomaterials with controllable photoluminescence.

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Efficient one-pot synthesis of highly monodisperse carbon quantum dots

Abstract: Type of publicationArticle (

Cited by 38 publications

References 25 publications

Size controlled synthesis of carbon quantum dots using hydride reducing agents

Size controlled synthesis of carbon quantum dots using hydride reducing agents

Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response

In Situ Nanoreactors: Controllable Photoluminescent Carbon‐Rich Polymer Nanodots Derived from Fatty Acid under Photoirradiation

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