Optical characterization of carbon quantum dots in colloidal suspensions

Castro, Hemerson P. S.; Pereira, Magnus Kaldieff; Ferreira, Vinícius Castro; Hickmann, Jandir M.; Correia, Ricardo Rego Bordalo

doi:10.1364/ome.7.000401

Cited by 25 publications

(16 citation statements)

References 31 publications

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“…Figure 3 shows the FTIR spectra of suspension of CNPs suspended in PEG 200 . The whole spectrum together with the position of vibrational absorption band of carboxylate group C=O at 1647 cm − 1 is very similar to that presented by Castro et al [12]. The intrinsic features of CDots spectrum are overshadowed by the absorption of PEG and can be well The size of carbon particles was measured by dynamic light scattering technique (DLS) using Zetasizer Nano ZS (Malvern Instruments Ltd., UK).…”

Section: Resultssupporting

confidence: 70%

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Fluorescent carbon and graphene oxide nanoparticles synthesized by the laser ablation in liquid

et al. 2018

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The results of synthesis of the fluorescent carbon dots (CDots) from graphite target and reduced graphene oxide (rGO) nanoparticles performed by the nanosecond laser ablation in polyethylene glycol 200 (PEG 200) are shown. Two-step laser irradiation (first graphite target, next achieved suspension) revealed a very effective production of CDots. However, the ablation in PEG appeared to be effective with 1064 nm laser pulse in contrast to the ablation with 355 nm laser pulse. In the case of rGO nanoparticles similar laser irradiation procedure was less efficient. In both cases, received nanoparticles exhibited strong, broadband photoluminescence with a maximum dependent on the excitation wavelength. The size distribution for obtained CDots was evaluated using the DLS technique and HRTEM images. The results from both methods show quite good agreement in nanoparticle size estimation although the DLS method slightly overestimates nanoparticle's diameter.

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Section: Resultssupporting

confidence: 70%

“…However, the experiments with laser synthesis in PEG are rather scarce [3,5,12,13] and most of them were made in graphite powder [3,12,13]. For carbon dots produced by laser ablation of a carbon target in the presence of water vapor photoluminescence was achieved only after dots' surface passivation [5].…”

Section: Introductionmentioning

confidence: 99%

Fluorescent carbon and graphene oxide nanoparticles synthesized by the laser ablation in liquid

et al. 2018

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“…Figure shows the UV‐vis absorption spectra of the CDs and the AuNPs prepared in its presence. The absorption spectrum of CDs shows strong absorption at 260–320 nm, which may be due to the π‐π * and n‐π * transition of C=C and C=O functionality present within the CDs . Usually the absorption spectrum of CDs appear in the UV region and the tail extending towards the visible region.…”

Section: Resultsmentioning

confidence: 99%

Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

et al. 2019

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A novel biocompatible carbon nanoparticles, i. e., carbon dots (CDs) are prepared from cheap organic precursors and are used to synthesize gold nanoparticles (AuNPs). The formation of CDs are confirmed from their absorption and emission properties. The CDs not only acts as reducing agent but also stabilizes the resulting AuNPs. The high stabilizing effect of CDs can be attributed to their hydrophilic surfaces due to the presence of ‐C=O, ‐OH, etc. functional group as confirmed from FTIR spectral analysis. Basically, two types of AuNPs are observed, one is decahedron type particles and the other one is triangular plates. The size of decahedron type AuNPs are measured to be ∼ 30 nm, whereas those of triangular plates are ∼ 100 nm. These mixture of AuNPs are used to study a model catalytic reaction, i. e., reduction of 4‐nitrophenol by NaBH4 in which the reaction is completed in 5 Mins and the reaction follows the first order kinetics with a first order rate constant of 1.28 min−1. Moreover, the resulting AuNPs can be reused for further reactions and up to 4 cycles it has been observed that the efficiency of conversion remains ∼100% with this AuNPs catalyst. Thus, functional CDs not only catalyse the formation of AuNPs, but also give them enough stability for catalytic applications in many organic transformation reactions.

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“…Some natural ingredients that have been made C-dots, as flowers [10], fruit [11], fruit peels [12,13], vegetables [14], and leaves [15]. C-dots can be synthesized by several methods, as laser ablation [16], electrochemical [17], arc-discharge [3], ultrasonic [18], and microwave [13]. This method has several advantages, such as facile, fast, measurable and tunable surface conditions [19].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Poly (Ethylene Glycol) on the Photoluminescence Properties of Carbon Dots From Cassava Peels Synthesized by Hydrothermal Methods

Putro

Roza

Isnaeni

2019

SPEKTRA

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Carbon dots (C-dots) have been successfully synthesized from cassava peels using the hydrothermal method. The C-dots are further passivated using poly (ethylene glycol) (PEG) with a variation of the volume of 0.5 ml, 1.0 ml, and 1.5 ml. The properties of photoluminescence C-dots before and after PEG were characterized using photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectrophotometers. PEG succeeded in influencing PL C-dots properties, such as peak wavelength, PL intensity, and electron time decay. The addition of 0.5 ml of PEG to C-dots is the optimum condition and best with the peak wavelength, the PL intensity and, time decay electron is 507.52 nm, 5302 a.u, and 3.794031133 ns, respectively.

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Optical characterization of carbon quantum dots in colloidal suspensions

Cited by 25 publications

References 31 publications

Fluorescent carbon and graphene oxide nanoparticles synthesized by the laser ablation in liquid

Fluorescent carbon and graphene oxide nanoparticles synthesized by the laser ablation in liquid

Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

The Effect of Poly (Ethylene Glycol) on the Photoluminescence Properties of Carbon Dots From Cassava Peels Synthesized by Hydrothermal Methods

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