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Synthesis of carbon quantum dots in a Nafion matrix: Precursor effect on the ion transport properties
摘要： Carbon quantum dots have been prepared in a Nafion? matrix via the hydrothermal treatment of organic precursors, and the swelling and ion transport properties of the prepared composite materials have been characterized.
关键词： Nafion matrix,ion transport properties,carbon quantum dots,hydrothermal treatment
更新于2025-09-16 10:30:52
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Detection of Ascorbic Acid Using Green Synthesized Carbon Quantum Dots
摘要： In this work, carbon quantum dots (CQDs) were synthesized by microwave irradiation and were electropolymerized on glassy carbon electrode (GCE) to establish an electrochemical sensor for the selective detection of ascorbic acid (AA). Electrochemical behaviors of the prepared sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Herein, two wide linear responses were obtained in ranges of 0.01-3 mM and 4-12 mM with a low detection limit of 10 μM to AA. High sensitivities (44.13 μA-1 μM-1 cm-2, 9.66 μA-1 μM-1 cm-2, respectively) corresponding to the linear ranges were also achieved. In addition, the electrochemical sensor exhibited good selectivity and robust anti-interference ability toward AA in the presence of dopamine (DA) and uric acid (UA). These results showed that this sensor can be used as a promising tool to detect AA in real complex systems.
关键词： electrochemical sensor,selective detection,ascorbic acid,carbon quantum dots,microwave irradiation
更新于2025-09-16 10:30:52
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Rapid synthesis of B-N co-doped yellow emissive carbon quantum dots for cellular imaging
摘要： In order to avoid the interference of autofluorescence and improve tissue penetration capability of carbon quantum dots (CQDs) in biological imaging, the synthesis of long-wavelength emission CQDs was achieved in this work. Boron and nitrogen co-doped CQDs (BN-CQDs) were synthesized by one-step microwave assisted hydrothermal method with o-phenylenediamine as carbon and nitrogen source, boric acid as boron source. The BN-CQDs (QY ? 13.79%) synthesized under the optimal conditions exhibit excitation independence, a large Stoke shift, satisfactory fluorescent stability, good biocompatibility and low toxicity, which can meet the basic requirements as cell imaging agent. Cell imaging measurements prove their increased intracellular accumulation with the extension of incubation time with HeLa cells, and clearly observable BN-CQDs imaging for cell morphology. Hence BN-CQDs can be used as a good cell imaging agent.
关键词： Rapidity,Cellular imaging,Yellow emission,B-N co-doped carbon quantum dots
更新于2025-09-16 10:30:52
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Visible light induced efficient activation of persulfate by a carbon quantum dots (CQDs) modified ?3-Fe2O3 catalyst
摘要： In this study, a carbon quantum dots modified maghemite catalyst (CQDs@γ-Fe2O3) has been synthesized by a one-step solvothermal method for efficient persulfate (PDS) activation under visible light irradiation. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) characterization indicated that the formation of heterojunction structure between CQDs and γ-Fe2O3 effectively reduced the catalyst band gap (Eg), favoring the separation rate of electrons and holes, leading to remarkable efficient sulfamethoxazole (SMX) degradation as compared to the dark-CQDs@γ-Fe2O3/PDS and vis-γ-Fe2O3/PDS systems. The evolution of dissolved irons also demonstrated that CQDs could accelerate the in-situ reduction of surface-bounded Fe3+. Electron paramagnetic resonance (EPR) and radical scavenging experiments demonstrated that both ?OH and SO4?? were generated in the reaction system, while ?OH was relatively more dominant than SO4?? for SMX degradation. Finally, the reaction mechanism in the vis-CQDs@γ-Fe2O3/PDS system was proposed involving an effective and accelerated heterogeneous-homogeneous iron cycle. CQDs would enrich the photo-generated electrons from γ-Fe2O3, causing efficient interfacial generation of surface-bond Fe2+ and reduction of adsorbed Fe3+. This visible light induced iron cycle would eventually lead to effective activation of PDS as well as the efficient degradation of SMX.
关键词： Photocatalysis,Persulfate,Carbon quantum dots,Iron cycle
更新于2025-09-16 10:30:52
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Electric field-assisted synthesis of Pt, carbon quantum dots-coloaded graphene hybrid for hydrogen evolution reaction
摘要： A simple method for preparation of Pt, CQDs-coloaded graphene composite for hydrogen evolution reaction (HER) is established by electrolysis-solvothermal process. Graphene is obtained by electrochemical exfoliation of graphite in cathode, while carbon quantum dots (CQDs) and Pt nanoparticles (NPs) are in-situ generated in the electrolyte simultaneously. CQDs are evolved from propylene carbonate solvent and Pt NPs are derived from reduction of Pt intermediate species generated from anodic dissolution of Pt counter electrode during electrolysis process. Then Pt NPs and CQDs are well dispersed on graphene at subsequent solvothermal process. Work voltage and electrolyte type as the key electrolysis conditions are applied to control the concentration of CQDs and Pt NPs, which decides electrochemically active surface area and HER activity of obtained catalysts. Significantly, the obtained superior catalyst with trace amount of Pt (0.145 wt%), shows markedly enhanced catalytic HER activity with mass activity of 37.5 A mg?1 at ?50 mV in acidic solution, 68.2 times more active than Pt/C. This study provides a universal and promising methodology for synthesizing Pt, CQDs coloaded hybrid with the assistance of electric field as cost-effective catalysts for fuel cells.
关键词： Pt nanoparticles,Carbon quantum dots,Graphene,Hydrogen evolution reaction
更新于2025-09-16 10:30:52
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Investigations on Novel Carbon Quantum Dots Covered Nanofluid Insulation for Medium Voltage Applications
摘要： The extensive use of mineral oil for high voltage insulation applications has directed to widespread research works targeted at improving its dielectric and thermal characteristics. The present study investigates a novel nanofluid insulation prepared using carbon quantum dots (CQD) which is used for the surface treatment of SiO2 nanoparticles added to commercially available mineral oil. The proposed nanofluid referred as CQD–SiO2 nanofluid is tested for its insulation properties such as AC breakdown voltage (BDV), partial discharge (PD), lightning impulse (LI), dissipation factor (Tan-delta), volume resistivity, viscosity and thermal characteristics such as flash and fire point. The tests were conducted for three different nanofluid concentrations, that is, 0.01%wt, 0.05%wt and 0.1%wt. Weibull distribution analysis is carried out for breakdown data of BDV test and LI test. Results of CQD–SiO2 nanofluid are compared with mineral oil with and without SiO2 nanofillers. The results show that inclusion of CQD covered SiO2 nanoparticles have the capability to improve the AC breakdown strength by more than 100%, partial discharge inception voltage by 50%, lightning impulse withstand capabilities up to 20% and volume resistivity by 50%. It has also the tendency to slightly improve the flash point and fire point properties than the mineral oil. Significant reduction of PD magnitude and Tan-delta values are noticed with CQD–SiO2 nanofluid. Such results indicate that the CQD–SiO2 nanofluid can be a suitable candidate for MV insulation applications.
关键词： Carbon quantum dots,Liquid insulators,Nanofluid,Breakdown voltage,Partial discharge
更新于2025-09-12 10:27:22
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Functionalized graphene transistor for ultrasensitive detection of carbon quantum dots
摘要： Ubiquitous carbon nanomaterials have great potential for emerging technologies, but they also pose a threat to human health at the end of their lifecycle, especially when they are introduced into waste or ground waters. Graphene field-effect transistors (GFET) and real time in situ confocal Raman microscopy (CRM) were employed to detect a submonolayer of carbon quantum dots (CQDs) in water. An effective GFET channel was formed on exfoliated and chemical vapor deposited (CVD) graphene. The adsorption of CQDs was monitored by measuring conductance changes in GFETs. The graphene channel was functionalized with (3-aminopropyl) triethoxysilane (APTES), which allowed for easy observation of a shift in the charge neutrality point (CNP) when the graphene channel was exposed to CQDs. The affinity of the CQD’s carboxyl terminal groups to the aminofunctionalized channel enabled a highly sensitive CQD detection based on changes in the GFET conductivity. The adsorption of the CQDs induced a positive shift of the CNP with a limit of detection at concentrations of 239 ppm and 62 ppm for the exfoliated and CVD graphene, respectively. A supporting study of graphene functionalization and CQD adsorption was performed by real time in situ CRM, ellipsometry, and ex situ X-ray photoelectron spectroscopy.
关键词： graphene field-effect transistors,carbon quantum dots,confocal Raman microscopy,chemical vapor deposited graphene,aminofunctionalized channel
更新于2025-09-12 10:27:22
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Carbon quantum dot-AgOH colloid fluorescent probe for selective detection of biothiols based on the inner filter effect
摘要： Here, we present a selective and sensitive fluorescent probe for the detection and distinction of biothiols, such as glutathione (GSH) and cysteine (Cys). The adsorbance of Cys onto the surface of AgOH colloid could result in enhanced absorbance from 250 to 400 nm in the UV–vis absorption spectrum, while the addition of GSH could dissolve the AgOH colloid resulting in no change in the UV–vis absorption spectrum. Utilizing these different phenomena, two fluorescent probes were established based on the inner filter effect (IFE). The first probe, the “CDs-AgOH colloid” fluorescent probe, was used to quantitatively analyze Cys over a linear concentration range from 33 to 317 μM and a detection limit of 7.2 μM. The second probe, the “CDs-AgOH colloid-Cys” fluorescent probe, was used to quantitatively analyze GSH, with a detection limit down to 3.6 μM, and a linear range of detection of approximately 16.7 to 100 μM. The fluorescent probes were successfully applied for the detection of GSH in a fetal bovine serum (FBS) sample. Based on these results, IFE is considered to be an effective way to distinguish GSH and Cys.
关键词： Fluorescent probe,AgOH colloid,Carbon quantum dots,Inner filter effect,Biothiols
更新于2025-09-12 10:27:22
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Carbon quantum dot-incorporated nickel oxide for planar p-i-n type perovskite solar cells with enhanced efficiency and stability
摘要： Carbon quantum dots (CQDs) have attracted extreme interest as a promising nanocarbon platform for divergence optoelectronics due to their high stability, good dispersibility in solvents, and tunable optical and electronic properties. Herein, planar p-i-n type perovskite solar cells (PSCs) with enhanced efficiency and long-term stability were developed by incorporating CQDs into a nickel oxide (NiO) hole transport layer (HTL). The incorporation of CQDs downshifts the band structure of NiO, leading to good alignment with the work-function of the tin-doped indium oxide (ITO) electrode and the band-edges of the perovskite. The efficient cascade charge transport achieved with the optimized incorporation ratio of CQDs resulted in an enhanced power conversion efficiency (PCE) of 17.02%, compared to that of the PSC fabricated with bare NiO (15.66%), even though they were fabricated in air. The suppressed charge recombination accompanied by restricted charge accumulation curtails the J-V hysteresis, with a reduction from 4.5% to less than 1%. Moreover, long-term stability under atmospheric conditions without any encapsulation was achieved with CQD-incorporated NiO. More than 70% of the initial PCE was retained over 190 h. This work suggests a novel strategy for fabricating solution-processible metal oxide interlayers with highly efficient charge migration for divergence energy conversion devices.
关键词： Carbon quantum dots,Nickel oxide,Hole transport layer,Stability,Perovskite solar cells
更新于2025-09-12 10:27:22
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Sweet Corn <i>(Zea mays L. var. rugosa)</i> Derived Fluorescent Carbon Quantum Dots for Selective Detection of Hydrogen Sulfide and Bioimaging Applications
摘要： We report a green, simple, and facile fluorometric method for the detection of hydrogen sulfide (S2?) using bluish green carbon quantum dots (CQDs) derived from sweet corn (Zea mays L. var. rugosa) as carbon source. The optical properties of the CQDs were studied using UV-visible, PL spectra and lifetime measurements. High-resolution transmission electron microscopy (HR-TEM), atomic force microscope (AFM) and dynamic light scattering (DLS) were used for morphological studies. X-ray diffraction (XRD) technique was used for phase analysis. Zeta potential, Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS) were used to measure the charge and composition of QDs. The prepared CQDs having size less than 2.4 nm with bluish green emission at ～ 470 nm and showed excellent stability for more than 6 months in aqueous medium. The synthesized CQDs showed highly sensitive and selective detection of sulfide ions (S2?) in aqueous medium over other toxic metal ions and inorganic salts, and the detection limit was 8 nM in the linear range from 5 to 100 nM. The synthesized CQDs had excellent hemocompatibility as evidenced from the hemolytic assay (2.86 %) and ESR estimation (7.5 mm/h) on human RBCs. The cell viability of CQDs was evaluated on Vero and A549 cell line by MTT assay, which produced more than 90 % of cell viability in both cell lines at 250 μg/mL concentration. Owing to their biocompatible nature, the synthesized CQDs were used as a fluorescent probe for in vitro bioimaging applications.
关键词： Bioimaging,Sweet corn,Sensor,Hydrogen sulfide,Carbon quantum dots
更新于2025-09-12 10:27:22