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Smart choice of carbon dots as a dual-mode onsite nanoplatform for the trace level detection of Cr2O72-
摘要： Efficient ways for the trace level monitoring of Cr2O7 2? have generated considerable attention in the fields of medical diagnosis and environmental protection. In current research, the water-soluble carbon dots (CDs) have been developed via the precursors of 1,3-phenylenediamine and citric acid. The quantum dots with particle size of 3–4 nm have been prepared based on a simple one-pot ultrasonic irradiation method and demonstrate bright blue emission at 440 nm. Its excitation-dependent feature has been explored and the achieved emission evolves from blue (440 nm) to green luminescence (528 nm). Photophysical studies support that CDs can be remarkably quenched by the presence of chromate due to inner filter effect. In addition, the absorption curves demonstrate that carbon dots possess highly selective and sensitive responses to Cr2O7 2? through color changes. The dual sensing modes (fluorescence and colorimetric detection) can be well-established for the recognition of chromate and the detection limits are calculated to be as low as 140 nM and 410 nM respectively. To further evaluate the analytical potentials of such nano-platform, the concentration of Cr2O7 2? have been determined in real water and river samples.
关键词： Ultrasonic,Luminescence,Carbon dots,Sensor
更新于2025-09-23 15:21:01
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Carbon Dots as Theranostic Agents || Carbon Dots for Cell Imaging and Diagnostics
摘要： Not only CDs, but many carbon allotropes showing graphitic structure, i.e., honeycomb-like arrangement of carbon atoms, have shown potential for various applications in electronic devices in biosensors and bioimaging agents. Some examples of these are 0D fullerene [274], diamond nanocrystals [123] and carbon dots (CDs), as well as 1D CNT [275], 2D graphene QD (GQDs) [276] and graphene [277]. However, it must be mentioned here that although CDs and GQDs have similar quantum-confined fluorescent carbon materials, CDs have been more used as biosensors and bioimaging agents [278]. Both CD and GQD are mainly composed of sp2 carbon, oxygen and nitrogen elements and other doped heteroatoms [24, 101]; the different spatial arrangements of carbon atoms exhibit distinctive physical and chemical properties [279]. Unlike GQD, the CDs do not have perfect crystal structures [42]. Moreover, CDs exhibit luminance at size < 10 nm, whereas GQDs have size up to 100 nm [280, 281] and are luminescent. Generally, CDs display strong optical absorption in the UV region, with a tail extending out into the visible range (Figure 5.1a), i.e., 280–360 nm. The absorption band could be regulated via surface passivation or modification. CDs show the excitation-dependent emission properties in wavelength and intensity (Figure 5.1b). Other properties that make CD more applicable for biomedical applications are their low cost, high quantum yield, abundant source, low cytotoxicity, and superior chemical and photo stability. Wang et al. [282] have evaluated the cytotoxicity of the CDs prepared by different combinations of precursor of CDs and molecules used for surface functionalization. It is found that in terms of their nanoscale structure and configuration CDs are not intrinsically cytotoxic. The cytotoxicity of CD depends on the selection of surface passivation molecules.
关键词： quantum yield,theranostic agents,bioimaging,carbon dots,photoluminescence,biosensors,cytotoxicity
更新于2025-09-23 15:21:01
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Review on Carbon Dots in Food Safety Applications
摘要： As a new class of promising fluorescent carbon nanomaterials, carbon dots (CDs) have been well developed in recent years for their excellent fluorescent properties, simple synthetic approaches, good biocompatibility and various detection applications, which can be expected to replace the tradition semi-quantum dots. This review aims presents the current progress in the development of CDs with an emphasis on fluorescent properties, synthetic approaches and applications in food safety. First, the fluorescent properties of CDs are briefly introduced. To seek more reasonable synthetic approaches, the characteristics of the diverse methods of CD synthesis are summarized. And then, applications of CDs as fluorescent probes in food safety are discussed, with emphasis on the determination of metal ions/anions, pesticides, veterinary drugs, bacteria, functional components and banned additives. Finally, the challenges, such as how to explain the diversity of fluorescent properties, and how to form a uniform synthesis procedure to improve the quantum yield (QY), for CDs are presented. Although CDs have found many applications in food safety, it is still a challenge to detect a specific target in complex samples. Therefore, combination with other biochemistry technology to exploit novel ligands against the specific target with high binding affinity and selectivity is vitally important for developing sensitive and specific sensing probes in the future.
关键词： carbon dots,sensors,fluorescent properties,food safety
更新于2025-09-23 15:21:01
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Fluorescent hollow mesoporous carbon spheres for drug loading and tumor treatment through 980-nm laser and microwave co-irradiation
摘要： Hollow mesoporous particles for drug delivery and cancer therapy have attracted significant attention over recent decades. Here, we develop a simple and highly efficient strategy for preparing fluorescent hollow mesoporous carbon spheres (HMCSs). Compared with typical carbon materials such as fullerene C60, carbon nanotubes, reduced graphene oxide, and carbon nanohorns; HMCSs showed fewer effects on cell cycle distribution and lower toxicity to cells. Ten different drugs were incorporated into the HMCSs, and the maximum loading efficiency reached 42.79 ± 2.7%. Importantly, microwaves were found to improve the photothermal effect generated by HMCSs when combined with 980-nm laser irradiation. The cell killing and tumor growth inhibition efficiencies of HMCSs and drug-loaded HMCSs under co-irradiation with laser and microwaves were significantly improved compared with those under laser irradiation alone. After local administration HMCSs were only distributed in tissue at the injection site. HMCSs showed almost no toxicity in mice after local injection and could be completely removed from the injection site.
关键词： Hollow mesoporous carbon spheres,Low cytotoxicity,Fluorescent carbon dots,980-Nm laser and microwave co-irradiation,Improved cancer therapy
更新于2025-09-23 15:19:57
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Advance in carbon dots: a perspective from traditional quantum dots
摘要： Quantum dots (QDs) have been the core concept of nanoscience and nanotechnology since its inception, and play a dominant role in the development of the nano-field. Carbon dots (CDots), defined by a feature size of ?10 nm, have become a rising star in the crossing field of carbon materials and traditional QDs (TQDs). CDots own many unique structural, physicochemical and photochemical properties that render them a promising platform for biology, devices, catalysis and other applications. However, due to the complex nature of CDots, the profound understanding of the physical and chemical properties of CDots is still a great challenge. Many key issues including structure, synthesis, and optical properties are unclear, leaving opening arguments and nonuniform description of their basics. The achievements and experience of TQDs in the past four decades are expected to provide crucial values for further development of CDots. Here, we will compare the research outputs of TQDs and CDots and try to give a comprehensive picture on their differences and correlations in structure, synthesis, properties and applications. Along this way, further perspectives are given on future directions and key issues toward better understanding of the basic properties of TQDs and CDots in a unifying manner. We expect researchers in the community to foresee the great potential of CDots, and focus on the critical thinking from the development of TQDs, paying special attention to the profound principles behand the synthetic chemistry, luminescence mechanisms and applications.
关键词： Carbon dots,Quantum dots,Photochemical properties,Biology,Nanoscience,Catalysis,Devices,Nanotechnology
更新于2025-09-23 15:19:57
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Purple-emissive carbon dots enhance sensitivity of Si photodetectors to ultraviolet range
摘要： In this work, we realized the synthesis of purple-emissive carbon dots (p-CDs) by a facile and highly reproducible route using folic acid as a sole precursor. The emission of the p-CDs is located around 390 nm, and independent of the excitation wavelength with a high photoluminescence quantum yield of 54.6%, thus complementing an emission color palette of brightly emitting carbon dots to a purple. Purple-emissive CDs are highly stable in both the colloidal state and in polymer films. A carbon dot luminescence down-shifting layer is used to sensitize a Si photodetector to UV range. As an example, p-CDs with an excitation maximum at 330 nm were integrated into Si photodetector, resulting in improving the photoresponsivity in a UV range from 0.8 to 2.5 mA/W, with a relative enhancement of 203.8%. This work represents a cheap, scalable and environmentally friendly way to create purple-emissive carbon dots enhancing the photoresponsivity of commercial photodetectors in a UV range thus being applicable in optical power meters, optical wireless communication systems, sunlight sensors, spectrophotometers, or radiation detectors.
关键词： UV range,Si photodetector,carbon dots,purple-emissive,photoluminescence
更新于2025-09-23 15:19:57
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Silver nanosol SERS quantitative analysis of ultratrace biotin coupled N-doped carbon dots catalytic amplification with affinity reaction
摘要： Highly catalytic and stable N-doped carbon dots (N-CDs) were prepared rapidly by microwave procedure using glucose as precursor and ammonium sulfite as N-dopant. The reduction of AgNO3 by trisodium citrate (TCA) was slow to form nanosilver (AgNP), and the N-CDs exhibited strong catalysis of the AgNP reaction. The formed AgNPs were used as indicator in the presence of Vitoria blue B (VBB) molecule probe with a SERS peak at 1615 cm?1. With the increase of nanocatalyst N-CDs concentration, the AgNP reaction speed up, and the SERS peak of VBB enhanced linearly due to formation of more AgNPs as substrate. In the presence of avidin (Ad), the SERS peak weakened. Upon addition of biotin, the SERS peak enhanced due to turn on the indicator nanoreaction. The enhanced SERS signal had a good linear relationship with the biotin concentration in range of 0.0006–0.021 ng/mL, with a detection limit of 0.3 pg/mL.
关键词： Nanocatalysis,N-doped carbon dots,SERS,Affinity reaction,Biotin
更新于2025-09-23 15:19:57
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Green and Orange Emissive Carbon Dots with High Quantum Yields Dispersed in Matrices for Phosphor-Based White LEDs
摘要： Carbon dots (CDs) have aroused more interest in the LED phosphor. High quantum yields and suppressing solid-state luminescence quenching are the key factors for CDs to prepare high-quality phosphors. In this work, orange and green emissive CDs (O-CDs and G-CDs) with very high absolute quantum yields (abs. QYs: 85.19% at natural pH and 96.12% at pH 9.0 for G-CDs; 34.89% in aqueous solution and 77.54% in ethanol for O-CDs) were achieved. Then, sodium silicate and PVA were selected as matrices to suppress their aggregation-induced quenching effect. Phosphor powder was prepared by microwave-assisted pyrolysis of sodium silicate and films by self-assembling of PVA in the presence of the CDs. The phosphor powder simultaneously containing G-CDs and O-CDs (G-O-CDs-phosphor) presents bright yellow fluorescence but owns a relatively low abs. QY. However, O-CDs/PVA and G-CDs/PVA phosphor films possess very high abs. QYs of 51.51% and 72.81%, respectively. LEDs constructed by coating G-O-CDs-phosphor on a blue chip exhibited a cool white color and a color rendering index (CRI) of 78. Interestingly, high-quality warm white LEDs owning a superior CRI of 93 were achieved by the O-CDs/PVA and G-CDs/PVA films. By comparison, PVA is more suitable to maintain the high performance of G-CDs and O-CDs for high-quality phosphors.
关键词： White LEDs,Phosphor,Carbon dots,High quantum yield,Rhodamine B
更新于2025-09-23 15:19:57
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Formation of carbon quantum dots and graphene nanosheets from different abundant carbonaceous materials
摘要： Carbon quantum dots (CQDs) and graphene nanosheets (GNs) are one of the most attractive fluorescent carbon nano-sized materials with unique features of optical and physico-chemical properties having various applications in chemical sensing, biomedicine, semiconductor devices, photo-catalyzing, and electrocatalysis. The primary purpose of this preliminary work is the feasibility study for synthesis of nano-structured value-added carbon products i.e., CQDs and GNs from cheap and abundant carbon sources, such as coal, petroleum coke, graphite, and coal-based humic acid by hydrothermal techniques. The physico-chemical properties of the raw precursors were evaluated by proximate and ultimate analysis. High resolution-transmission electron microscopy (HR-TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared (FT-IR) spectroscopy, X-ray powder diffractometer (XRD), UV-visible (UV-vis), and fluorescence (FL) spectrophotometer were used to achieve physico-chemical parameters of carbon nanostructures, to better comprehend the development of carbon quantum dots and graphene nanosheets. HR-TEM analysis indicates that the dimensions of the synthesized CQDs from different carbon sources exist in the range of 3-6.5 nm. The approximate quantum yields (QY) of the synthesized carbon nanomaterials were found to be about 2-22%. The synthesised carbon based nanomaterials (i.e. CQDs and GNs) have been efficiently used in the photo-degradation of harmful 2-nitrophenols (2-NP) with the efficiency of 80.79% for CQDs and 82.53% for GNs, respectively. The present study provides a simple and environmentally-sound technique for large-scale fabrication of typical CQDs and GNs from abundantly available low-grade coal and other carbonaceous materials for photo-catalysis application.
关键词： Carbon Dots,Photocatalytic degradation,Carbonaceous materials,Graphene nanosheet,Hydrothermal treatment,Fluorescent materials
更新于2025-09-23 15:19:57
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Photocatalytic Hydrogen Generation Coupled to Pollutant Utilization Using Carbon Dots Produced from Biomass
摘要： Photocatalysis is deemed as an appealing strategy to exploit solar energy for simultaneous fuel production and pollutant utilisation. However, current photocatalytic systems rarely couple both processes and suffer from restricted scalability and sustainability as they use toxic and/or ultraviolet light harvesters, combined with noble-metal co-catalysts under corrosive conditions. Here, we show the synthesis of ultra-scalable and low-cost carbon nanodots from lignocellulosic waste, which when combined with a non-precious Ni-based co-catalyst, use visible light to drive H2 production in untreated river and sea water. Organic pollutants and chloride anions in these untreated media do not only allow unhindered photocatalytic activities, but also function as electron donors leading to economical pollutant utilisation. This system combines Earth’s most abundant resources (biomass, solar energy, untreated water), and functions at ambient temperature, pressure and physiological pH creating perspectives for simultaneous fuel synthesis and pollutant utilisation of sustainable and practical character.
关键词： Pollutant utilisation,Carbon dots,Photocatalysis,Biomass waste,Hydrogen production
更新于2025-09-23 15:19:57