Scalable synthesis of highly photoluminescence carbon quantum dots

Dũng, Mai Xuân; Kim, Tran Thi; Nguyen, Truong-Chung; Ta, Van-Thao

doi:10.1016/j.matlet.2020.127595

Cited by 47 publications

(31 citation statements)

References 18 publications

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“…All samples also exhibited bands coming from -CH 2 - and CH 3 aliphatic groups in the range between 2930 and 2840 cm −1 . The chemical structure is typical for the CQDs and corresponds to other researchers’ data [ 20 , 25 ]. The presence of various functional groups is important for the selective interactions with various molecules.…”

Section: Resultssupporting

confidence: 78%

“…All of the CQDs were characterized by two peaks visible approximately at 205 nm and 260 nm, which are typical for the electron transitions occurring in carbons with sp 2 hybridization (π–π* type) present in the carbon core of the nanodots. The UV-Vis spectra are characteristic for carbon quantum dots [ 20 , 25 , 30 ]. The highest intensity is observed in the case of the CQDs-2 and CQDs-7 samples.…”

Section: Resultsmentioning

confidence: 99%

“…What is interesting, the choice of the modifying agent affected the PL properties in various ways and there was no general tendency for all of the samples, similarly as in the case of the optical characteristics of the products. The fluorescence of the prepared samples was a result of the disruption of the crystalline structure along with the band gap transitions (conjugated π-type bonds), which is characteristic for carbon quantum dots [ 5 , 6 , 14 , 20 , 25 , 29 , 30 ]. Figure 7 presents the CQDs solutions irradiated with the commercially available diode, which exhibit blue fluorescence at λ = 365 nm.…”

Section: Resultsmentioning

confidence: 99%

“…They may have a crystalline or amorphous structure. Carbon quantum dots fluorescence can be explained by surface defects or conjugated π-bonds bandgap transitions [ 20 , 25 , 26 , 27 , 28 , 29 , 30 ]. The nanodots can be prepared via two different approaches, namely top down and bottom up.…”

Section: Introductionmentioning

confidence: 99%

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Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

et al. 2020

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Recently, fluorescent probes became one of the most efficient tools for biosensing and bioimaging. Special attention is focused on carbon quantum dots (CQDs), which are characterized by the water solubility and lack of cytotoxicity. Moreover, they exhibit higher photostability comparing to traditional organic dyes. Currently, there is a great need for the novel, luminescent nanomaterials with tunable properties enabling fast and effective analysis of the biological samples. In this article, we propose a new, ecofriendly bottom-up synthesis approach for intelligent, surface-modified nanodots preparation using bioproducts as a raw material. Obtained nanomaterials were characterized over their morphology, chemical structure and switchable luminescence. Their possible use as a nanodevice for medicine was investigated. Finally, the products were confirmed to be non-toxic to fibroblasts and capable of cell imaging.

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Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

et al. 2020

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“…e latest type has been vastly reported and interchangeably called as CQDs owing to their simple synthesis and facile tunability in chemical composition and functionality [6,7]. CQDs can be facilely synthesized by solvothermal methods using simple organic precursors such as citric acid, ethylenediamine, urea, thiourea, and phenylenediamine.…”

Section: Introductionmentioning

confidence: 99%

Excitation‐Independent Emission of Carbon Quantum Dot Solids

Dũng

Phan

Nguyen

2020

Advances in Materials Science and Engineering

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Solid assemblies of carbon quantum dots (CQDs) are important for diverse applications including LEDs, solar cells, and photosensors; their optical and electrical properties have not been explored yet. Herein, we used amphiphilic CQDs synthesized from citric acid and thiourea by a solvothermal method to fabricate CQD solid films. Optical properties of CQDs studied by UV-Vis and photoluminescence spectroscopies indicate that CQDs possess three different emission centers at 425 nm, 525 nm, and 625 nm originating from C sp2 states, N-states, and S-states, respectively. In a solid state, π-π stacking quenched the blue emission, while the red emission increased. Importantly, CQD films exhibited excitation independence, which is important to design solid-state lighting applications.

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Exploration of Room‐Temperature Phosphorescence and New Mechanism on Carbon Dots in a Polyacrylamide Platform and their Applications for Anti‐Counterfeiting and Information Encryption

Wang

Zhang

et al. 2022

Advanced Optical Materials

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devices, sensing, biological imaging, and display [1][2][3][4] due to their long-life characteristics. Carbon dots (CDs) as the emerging carbon nano-luminescent materials, due to their unique optical properties, low toxicity, chemical inertness, and easy preparation, [5][6][7][8] stand out among many luminescent materials and become the important parts of RTP materials. Different CDs fluoresce in unique ways under different states. CDs in dilute solutions have different photophysical properties compared with solid or highconcentration solutions. Moreover, CDs follow the aggregation-caused quenching (ACQ) effect. [9] For example, the luminescence of CDs will be weakened in the solid-state. The reasons for the quenching are the excessive fluorescence resonance energy transfer (FRET) and the π-π stacking interaction between the carbon cores, resulting in the non-radiative loss of the excited state. [10][11][12][13] The luminescence of CDs in the solid-state is obviously quenched due to the ACQ effect, which severely limits their development in the direction of RTP materials.Theoretically, the best way to prepare CDs-based RTP materials and solve the problem of CDs luminescence quenching in the solid-state, the current effective method is to stabilize triple states (T 1 ) , suppress the nonradiative transitions, and limit vibrations and rotations of molecules by embedding CDs into appropriate substrates with the help of hydrogen bonds. [14][15][16][17] The phosphorescence phenomenon in the CDsbased composite system has attracted more and more attention in recent years. [14][15][16][18][19][20][21] Gou et al. reported a series of RTP composites based on tunable polyaniline CDs (PACDs) and polymer matrices (polyacrylic acid, polyacrylamide (PAM), polyvinyl alcohol (PVA)). Only green RTP emissions with adjustable lifetime have been realized by the hydrogen bonding formed between polymer matrices and PACDs. [14] Li et al. prepared an efficient CDs-based RTP material by mixing N-doped CDs (NCDs) with urea and biuret through one-pot heating method. The appearance of CN bonds creates new energy level structures. The interaction of the mixture of biuret and NCDs with composite matrices is This is the first report of full-color afterglow composites composed of four multicolored (blue, green, orange, and red) carbon dots (CDs) in polyacrylamide (PAM) matrix. Thus, adjustable four-color room-temperature phosphorescence (RTP) CDs@PAM composites are prepared on a PAM platform. The abundant amide groups in PAM are connected to the functional groups in CDs by hydrogen bonds, which promote the intersystem crossover and inhibit the non-radiative relaxation of triple states (T 1 ) in CDs@PAM and effectively shield the quenching agents such as oxygen. Furthermore, the rigid hydrogen bond mesh structure is beneficial to the stability of T 1 in CDs@PAM. In addition, the results of electron spin resonance reveal that the afterglow of CDs@PAM composites is not caused by oxygen defects and the increase of oxygen defects hinders the emissio...

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Scalable synthesis of highly photoluminescence carbon quantum dots

Cited by 47 publications

References 18 publications

Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

Excitation‐Independent Emission of Carbon Quantum Dot Solids

Exploration of Room‐Temperature Phosphorescence and New Mechanism on Carbon Dots in a Polyacrylamide Platform and their Applications for Anti‐Counterfeiting and Information Encryption

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