Excitation wavelength independent visible color emission of carbon dots

Wang, Hua; Sun, Chun; Chen, Xingru; Yu, Zhangjun; Colvin, Vicki L.; Rice, Quinton; Seo, Jaetae; Feng, Shengyu; Wang, Shengnian; Yu, William W.

doi:10.1039/c6nr09200d

Cited by 380 publications

(282 citation statements)

References 42 publications

(42 reference statements)

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“…In different solvents, not only the orientation of the solvent dipole but also the hydrogen‐bonding interactions between the solute and solvent are different, thereby resulting in tunable PL, known as solvatochromism. When the CDs were dissolved in solvents of different polarity, from toluene to water, the emission was redshifted with increasing solvent polarity (Figure ) . In polar protic solvents, the hydrogen‐bonding interaction between the functional groups of CD and the solvent was strong.…”

Section: Optical Propertiesmentioning

confidence: 99%

“…When the CDs wered issolved in solvents of different polarity, from toluene to water,t he emission was redshifted with increasings olvent polarity( Figure 5). [49] In polar protic solvents, the hydrogen-bonding interaction between the functional groups of CD and the solvent was strong. Thus, non-radiative recombination was enhanced, producingared emission.…”

Section: Solvatochromismmentioning

confidence: 99%

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Carbon Dots: Bottom‐Up Syntheses, Properties, and Light‐Harvesting Applications

Choi

Kwon

et al. 2018

Chemistry An Asian Journal

111

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The development of cost-effective and environmentally friendly photocatalysts and photosensitizers has received tremendous attention because of their potential utilization in solar-light-harvesting applications. In this respect, carbon dots (CDs) prepared by bottom-up methods have been considered to be promising light-harvesting materials. Through their preparation from various molecular precursors and synthetic methods, CDs exhibit excellent optical and charge-transfer properties. Furthermore, their photophysical properties can be readily optimized and enhanced by means of doping, functionalization, and post-synthetic treatment. In this review, we summarize the recent progress in CDs synthesized using bottom-up approaches. These CDs exhibit strong light absorption and unique electron donor/acceptor capabilities for light-harvesting applications. We anticipate that this review will provide new insights into novel types of photosensitizers and photocatalysts for a wide range of applications.

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Section: Optical Propertiesmentioning

confidence: 99%

Section: Solvatochromismmentioning

confidence: 99%

Carbon Dots: Bottom‐Up Syntheses, Properties, and Light‐Harvesting Applications

Choi

Kwon

et al. 2018

Chemistry An Asian Journal

111

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“…As for the PL mechanism, Lin and his co‐workers mentioned in another paper that CDs exhibiting excitation wavelength‐independent PL reflects surface states rather than size effect, and the surface states should be rather uniform . Such CDs are often reported to have solvent effect but with relatively low quantum yield ,. Therefore, the improvement of QY of such CDs should be investigated.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescent Carbon Dots: A Mixture of Heterogeneous Fractions

et al. 2018

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Photoluminescent carbon dots (CDs) fractions have been isolated from a gel-like material (GM), which was synthesized using a convenient one-step solvothermal route. In terms of purification, size exclusion chromatography (SEC) and dialysis were compared with acetone wash, which revealed the advantage of acetone wash. The pre-purified GM with acetone wash (A-GM) was further isolated by the reversed-phase preparative thin layer chromatography (TLC) with acetonitrile-water mixture (7 : 3; v /v ) as the developing solvent. As a result, there were four photoluminescent bands on the TLC plate, which indicated the presence of four photoluminescent fractions. Detailed characterization measurements such as UV/Vis absorption, fluorescence emission, attenuated total reflection Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential, dynamic light scattering, atomic force microscopy, and TEM measurements were performed on all fractions to analyze their heterogeneous optical, structural, electrical, and morphological properties. Considering the comprehensive analysis, all isolated fractions were CDs. In addition, excitation wavelength-independent CDs were obtained with a mean size of 2.5 nm and high quantum yield (55 %). Furthermore, the study demonstrates that the excitation wavelength-dependent photoluminescence of GM could result from the mixture of different surface states of each CD fraction rather than multiple surface states of uniform CDs nanoparticles.

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“…The time‐resolved PL spectrum of O‐CDs in aqueous solution (Figure D) was double‐exponential with an average lifetime of 4.15 ns (τ 1 : 1.23 ns, α 1 : 69.2%; τ 2 : 10.72 ns, α 2 : 30.8%), revealing the singlet state nature of emission of the O‐CDs . Furthermore, the absolute PL quantum yield (QY) of O‐CDs was determined to be 3.54% under 440 nm excitation; one possible reason for the relatively low QY is mostly related to the self‐absorption because of large overlap between absorption and excitation; another possible reason is that the O‐CDs in aqueous solution suffered from massive resonance energy transfer or direct π–π interaction …”

Section: Resultsmentioning

confidence: 98%

Orange‐Emissive Carbon Quantum Dots: Toward Application in Wound pH Monitoring Based on Colorimetric and Fluorescent Changing

Yang

Zhu

Zhang

et al. 2019

Small

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Monitoring of wound pH is critical for interpreting wound status, because early identification of wound infection or nonhealing wounds is conducive to administion of therapies at the right time. Here, novel orange‐emissive carbon quantum dots (O‐CDs) are synthesized via microwave‐assisted heating of 1,2,4‐triaminobenzene and urea aqueous solution. The as‐prepared O‐CDs exhibit distinctive colorimetric response to pH changing, and also display pH‐sensitive fluorescence. Benefiting from the response of O‐CDs over a wound‐relevant pH range (5–9), medical cotton cloth is selected to immobilize O‐CDs through hydrogen bond interactions, the resultant O‐CDs‐coated cloth with emission at 560 nm shows a high response to pH variation in the range of 5–9 via both fluorescence and visible colorimetric changes. Moreover, the sensitivity of fluorescence to pH is capable of establishing an analytical mode for determining pH value. Further, the O‐CDs‐based pH indicator possesses not only superior biocompatibility and drug compatibility but also excellent resistance leachability and high reversibility. Importantly, the usage of O‐CDs‐coated cloth to detect pH is free from the interference of blood contamination and long‐term storage, thus providing a valuable strategy for wound pH monitoring through visual response and quantitative determination.

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Excitation wavelength independent visible color emission of carbon dots

Cited by 380 publications

References 42 publications

Carbon Dots: Bottom‐Up Syntheses, Properties, and Light‐Harvesting Applications

Carbon Dots: Bottom‐Up Syntheses, Properties, and Light‐Harvesting Applications

Photoluminescent Carbon Dots: A Mixture of Heterogeneous Fractions

Orange‐Emissive Carbon Quantum Dots: Toward Application in Wound pH Monitoring Based on Colorimetric and Fluorescent Changing

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