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Regulatory Preparation of N/S Doped Carbon Quantum Dots and Their Applications as Fe(III) Ion Sensors
摘要： The nitrogen-sulfur co-doped fluorescent carbon quantum dots (N/S-CQDs) were synthesized from sulfanilic acid. The fluorescence emission was independent of the excitation wavelength. In this experiment, the carbonization degree of the precursors was adjusted by solvent-thermal method to affect the sp2 conjugated dimension of CQDs, thus affecting the fluorescence performance of CQDs. They are well dispersed in water and ethanol, and have high selectivity for Fe3 +. The detection range is 0.025 ～ 0.4 mmol/L, and the detection limit is about 2.549 μmol/L. The CQDs prepared in this experiment emit light indirectly through the surface defect state. When CQDs is illuminated by light, the carriers generated by photons will emit light at a very fast speed due to the surface defect state, so the excited electrons in CQDs can be easily transferred to Fe3 +, making the surface of CQDs more complete, thus leading to the quenching of CQDs fluorescence.
关键词： Fe3 + sensor,Nitrogen and sulfur co-doping,carbon quantum dots,Fluorescence
更新于2025-09-23 15:21:01
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A Review: Recent Advances in Preparations and Applications of Heteroatom-Doped Carbon Quantum Dots
摘要： Carbon quantum dots (CQDs) are widely used in optoelectronic catalysis, biological imaging, and ion probes owing to their low toxicity, stable photoluminescence, and ease of chemical modification. However, the low fluorescence yield and monochromatic fluorescence of CQDs limit their practical applications. This review summarizes the commonly used approaches for improving the fluorescence efficiency of CQDs doped with non-metallic (heteroatoms) elements. Herein, three types of heteroatom-doped CQDs have been investigated: (1) CQDs doped with a single heteroatom; (2) CQDs doped with two heteroatoms; and (3) CQDs doped with three heteroatoms. The limitations and future perspectives of doped CQDs from the viewpoint of producing CQDs for specific applications, especially for bioimaging and light emitting diodes, have also been discussed herein.
关键词： Carbon quantum dots,Doping,Photoluminescence,Heteroatoms
更新于2025-09-23 15:21:01
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Carbon quantum dots decorated on ZnO nanoparticles: An efficient visiblea??light responsive antibacterial agents
摘要： Zinc oxide@carbon quantum dots (ZnO@CQDs) nanocomposite was prepared via a facile hydrothermal method. Characterization of the obtained samples was carried out by Scanning electron microscopy-EDX(SEM–EDX), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Photoluminescence (PL), and Fourier transformed infrared spectroscopy (FT-IR). These results revealed that we have prepared ZnO@CQDs nanocomposite successfully. Our study revealed that the antibacterial efficiency (against S.aureus and E.coli) under visible light irradiation of as prepared ZnO@CQDs nanocomposite was higher than pure ZnO nanoparticles. The ZnO@CQDs nanocomposite showed excellent antibacterial activity against Gram-negative and Gram-positive bacteria with a minimal inhibitory concentration (6–8 mg/mL) against to E.coli and S.aureus. We also tested the light response of ZnO@CQDs under UV–vis light, by calculating its band gap data, after decorated with CQDs, the band gap of the pure ZnO can significantly decreased from 2.57 eV to 2.50 eV. The ZnO decorated by CQDs can both enhance the light absorption and suppress photogenerated electron–hole's recombination which results in the enhancement of antibacterial properties.
关键词： ZnO,carbon quantum dots,antibacterial
更新于2025-09-23 15:21:01
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One-pot synthesis of 2,2'-dipicolylamine derived highly photoluminescent nitrogen-doped carbon quantum dots for Fe3+ detection and fingermark identification
摘要： The novel nitrogen-doped carbon quantum dots (N-CQDs) with high fluorescence quantum yield of 23.2% were successfully prepared via a simple hydrothermal reaction with citric acid and 2,2'-dipicolylamine. The as-prepared blue fluorescent N-CQDs had excellent water dispersibility, and showed pH and excitation-dependent emission behaviors. Noticeably, owing to the strong interaction between the residual 2,2'-dipicolylamine group on the surface of N-CQDs and Fe3+, the N-CQDs could be used as a turn off fluorescence probe for Fe3+ sensing through an electron transfer process. Moreover, the photoluminescent N-CQDs/poly(vinyl alcohol) film was further applied for latent fingermark imaging.
关键词： Carbon quantum dots,2,2'-dipicolylamine,Fe3+ sensing,Latent fingermark detection
更新于2025-09-23 15:21:01
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Copper nanoclusters @ nitrogen-doped carbon quantum dots-based ratiometric fluorescence probe for lead (II) ions detection in porphyra
摘要： A novel ratiometric fluorescence probe was proposed for detecting lead (II) ions (Pb2+) in porphyra, the approach was based on copper nanoclusters and nitrogen-doped carbon quantum dots (CuNCs-CNQDs). In this probe, the CuNCs delivered the response signal, the fluorescence of which was enhanced by Pb2+ due to the aggregation-induced emission enhancement (AIEE) between Pb2+ and CuNCs. The CNQDs provided the self-calibration signal, whose fluorescence remained almost unchanged in coexistence with Pb2+. According to the change of fluorescence intensity ratio between the fluorophores, CuNCs–CNQDs nanohybrid was used as ratiometric probes for the sensitive detection of Pb2+ in the range of 0.010 to 2.5 mg L-1, with a detection limit of 0.0031 mg L-1. Finally, the probe was successfully applied to detect Pb2+ in porphyra with relative standard deviations (RSDs) lower than 5%. This study provides a straightforward, stable, and sensitive approach for detecting Pb2+ in porphyra.
关键词： Lead (II) ions,Ratiometric fluorescence probe,Aggregation-induced emission enhancement,Copper nanoclusters,Nitrogen-doped carbon quantum dots
更新于2025-09-23 15:21:01
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Organic Field-Effect Transistor Memory Device Based on an Integrated Carbon Quantum Dots/Polyvinyl Pyrrolidone Hybrid Nanolayer
摘要： In this work, we present a pentacene-based organic ?eld-e?ect transistor memory (OFETM) device, which employs one-step microwave-assisted hydrothermal carbon quantum dots (CQDs) embedded in a polyvinyl pyrrolidone (PVP) matrix, to form an integrated hybrid nanolayer as the charge trapping layer. The as-prepared CQDs are quasi-spherical amorphous C, with sizes ranging from 5 to 20 nm, with a number of oxygen-containing groups and likely some graphite-like domains that produce CQDs with excellent electron-withdrawing characteristics. The incorporation of CQDs into PVP dielectric materials results in a bidirectional storage property. By optimizing the concentration of CQDs embedded into the PVP matrix, the OFETM shows excellent memory characteristics with a large memory window of 8.41 V under a programming/erasing (P/E) voltage of ±60 V and a retention time of up to 104 s.
关键词： memory window modulation,integrated hybrid nanolayer,organic ?eld-e?ect transistor memory device,carbon quantum dots
更新于2025-09-23 15:21:01
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Visible light assisted photocatalytic reduction of CO2 to ethane using CQDs/Cu2O nanocomposite photocatalyst
摘要： CO2 reduction through photocatalysis is considered a promising way to mitigate the abundance of this greenhouse gas in the earth’s atmosphere. In this work, blue-fluorescent carbon quantum dots (CQDs) were synthesized via a facile top-down hydrothermal method using biochar as the carbon source. The as-synthesized CQDs were incorporated together with commercial copper (I) oxide (Cu2O) nanoparticles to form CQDs/Cu2O nanocomposite. The CQDs, Cu2O and CQDs/Cu2O nanocomposite were then applied for gas phase photocatalytic reduction of CO2. The experiments were performed under visible light irradiation in a self-designated photoreactor which was connected to an online Gas Chromatography (GC). High resolution transmission electron microscopy (HRTEM) confirmed the uniform deposition of CQDs with size ranging from 2.5 to 6.0 nm on the surface of Cu2O nanoparticles. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy further revealed the presence of CQDs on the surface of Cu2O. The CQDs/Cu2O nanocomposite photocatalyst showed a considerable improvement in the CO2 photoreduction with an enhancement of 54% compared to the pure Cu2O. In addition, the band alignment of CQDs/Cu2O, charge carriers transfer and separation as well as possible reaction pathways for CO2 photoreduction was proposed. Finally, the photostability test revealed the CQDs/Cu2O nanocomposite was able to retain its photostability of up to ~90% under five cycles of photoreaction.
关键词： copper (I) oxide,carbon quantum dots,CO2 photoreduction,photocatalyst
更新于2025-09-23 15:21:01
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A new nano biosensor for maitotoxin with high sensitivity and selectivity based fluorescence resonance energy transfer between carbon quantum dots and gold nanoparticles
摘要： Maitotoxin (MTX) is a potent marine toxin with critical LD50, which usually causes poisoning because of eating the contaminated marine crustaceans. This poison is a severe threat to neuronal systems and also disables the heart by increasing the calcium ions flow in the cardiovascular. Therefore, the quantitative determination of MTX by using a fast and cost-effective way is essential. Application of carbon dots in the structure of various sensors for the measurement of biological compounds has been developed due to its easy, rapid and inexpensive synthesis. In this study, carbon quantum dots (CQDs) and gold nanoparticles (AuNPs) were synthesized for the determination of MTX with high sensitivity and selectivity. The structure of CQDs and AuNPs were characterized using SEM (Scanning electron microscopy), TEM (Transmission electron microscopy), EDS (Energy-dispersive X-ray spectroscopy) and FT-IR (Fourier-transform infrared spectroscopy) techniques. The Basis of the sensing method is fluorescence resonance energy transfer (FRET) which occurs between energy donor (CQDs) and energy acceptor (AuNPs). Under optimal conditions (excitation wavelength 430 nm and emission wavelength 523 nm), the linear range and detection limit were obtained 1-600 pmol L-1 and 0.3 pmol L-1, respectively. The strong point of this nanosensor is its very fast quenching process. The interference effect of other poisons and some ions on the MTX determination were investigated using CQDs at the constant concentration of MTX 50 pmol L-1 and various concentrations of other species. The results show excellent selectivity for the measurement of MTX in the presence of other similar species.
关键词： Gold nanoparticles,Fluorescence Resonance Energy Transfer,Maitotoxin,Carbon Quantum Dots
更新于2025-09-23 15:21:01
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Carbon quantum dots originated from chicken blood as peroxidase mimics for colorimetric detection of biothiols
摘要： Carbon quantum dots (CQDs) were prepared from chicken blood by hydrothermal method, which could catalyze the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the presence of H2O2 to generate the blue oxidized TMB (ox-TMB) with a strong absorption peak at 652 nm. However, the introduction of biothiols could induce the reduction of ox-TMB, leading to shallower blueness and lower absorbance. Based on this fact, a convenient and sensitive colorimetric method for detection of biothiols using CQDs as peroxidase mimics was established. Several factors, such as acidity, temperature, incubating time, CQDs dosage, H2O2 and TMB concentrations, which might influence the response of the analysis signal, were optimized by taking cysteine (CySH) as an example. Under the selected conditions, sensitive detection of biothiols was achieved, and the limits of detection (LOD) for CySH, glutathione (GSH), and homocysteine (HcySH) were 0.4, 0.6, and 0.9 μM respectively. This method was successfully applied for the determination of CySH in human serum samples with the recovery of 91.5%–109.3%, indicating the potential application of this method for biothiols sensing in real samples.
关键词： Determination,Carbon quantum dots,Peroxidase mimics,Colorimetry
更新于2025-09-23 15:21:01
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Water hyacinth derived carbon quantum dots and g-C3N4 composites for sunlight driven photodegradation of 2,4-dichlorophenol
摘要： Carbon dots (CDs) were successfully derived from water hyacinth leaves and the binary composite was achieved by incorporating CDs with g-C3N4 through hydrothermal treatment. The average particle size of CDs was found to be 3.1 nm and a blue-green fluorescence was emitted under the UV light irradiation. Both of the composites loaded with 20 wt.% (20CDs/g-C3N4) and 40 wt.% (40CDs/g-C3N4) of CDs achieved the highest degradation efficiency of 2,4-dichlorophenol (2,4-DCP) with 1.7 times higher than that of pure g-C3N4. This work successfully improved the properties of g-C3N4 by elongating the lifetime of photogenerated electrons and widening the visible light response. Both of 20CDs/g-C3N4 and 40CDs/g-C3N4 recorded the highest photocatalytic performance in degrading 2,4-DCP with degradation rate constant of 0.0194, and 0.0186 min?1, respectively. This is contributed by the prolonged charge carrier lifetime in 20CDs/g-C3N4; good visible light absorption and high specific surface area in 40CDs/g-C3N4. For the scavenger test, hole (h+) and superoxide radical (·O2?) were acknowledged as the key active species in photocatalysis.
关键词： Carbon quantum dots,Water hyacinth,CDs/g-C3N4 composite,2,4-Dichlorophenol
更新于2025-09-23 15:21:01