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Carbon quantum dots (CQDs) modified ZnO/CdS nanoparticles based fluorescence sensor for highly selective and sensitive detection of Fe(III)
摘要： A simple and fast spectrofluorimetric method coupled with carbon quantum dots (CQDs) modified ZnO/CdS nanoparticles was developed for the detection of Ferric iron (Fe(III)). The fluorescence of CQDs/ZnO/CdS NPs was effectively quenched by Fe(III) due to the strong interaction between the CQDs/ZnO/CdS NPs and Fe(III). In addition, the detection limit of Fe(III) was about 1.72 × 10^-7 M. The effect of foreign ions on the fluorescence intensity of CQDs/ZnO/CdS NPs showed that the interference response in detecting of Fe(III) ions was low. Moreover, the quenching of Fe(III) and CQDs/ZnO/CdS NPs was discussed to be a static quenching procedure, which was proved by quenching constant KSV and fluorescence lifetime τ. The study of thermodynamics showed that the values of entropy change (?S) and enthalpy change (?H) were both positive, and the values of free energy (?G) was negative, which implied that the weak interaction of the molecular between CQDs/ZnO/CdS NPs and Fe(III) was hydrophobic force, and the quenching process was endothermic and spontaneous.
关键词： Static quenching,Ferric iron,CQDs/ZnO/CdS NPs,Fluorescence sensor
更新于2025-09-12 10:27:22
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Impact of aminated carbon quantum dots as a novel co-reactant for Ru(bpy)32+: resolving specific electrochemiluminescence for butein detection
摘要： Development of novel nanomaterial-based co-reactant is highly desired for enhancing ECL intensity and widespread analytical applications. Herein, we report the distinct role of amine-functionalized carbon quantum dots (f-CQDs) as a co-reactant, for the first time, augmenting the ECL property of Ru(bpy)3 2+ and demonstrating for biopharmaceutical (butein) detection. Unlike conventional co-reactants like tripropylamine (TPrA), 2-(dibutylamino)ethanol (DBAE), and pristine CQDs, the f-CQDs as a co-reactant yield superior ECL of Ru(bpy)3 2+. More importantly, the ECL intensity is independent of types of noble metals, metal oxide surfaces, and dissolved oxygen. Notably, the ECL intensity of Ru(bpy)3 2+–f-CQDs is linearly quenched with an increased concentration of butein, whereas no changes were observed with conventional co-reactants. ECL functionality of Ru(bpy)3 2+–f-CQDs has no interference with other similar phytochemicals and antioxidants. Enhanced selectivity is observed due to the formation of polyaminoquinone-like structures, which is confirmed by in situ spectroelectrochemical (UV–vis) and FT-IR studies. The present result envisaged that f-CQDs could be an alternative co-reactant for TPrA/DBAE, raising the ECL of Ru(bpy)3 2+ suitable for analytical studies.
关键词： Polyphenol,Functionalized carbon quantum dots (f-CQDs),Co-reactant,Electrochemiluminescence,Butein
更新于2025-09-12 10:27:22
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A facile approach to synthesis carbon quantum dots-doped P25 visible-light driven photocatalyst with improved NO removal performance
摘要： The water-soluble carbon quantum dots (CQDs) and a novel composite photocatalyst CQDs/P25 have been prepared by a one-step electrochemical-microwave method. The experimental result shows that the photocatalytic degradation of NO by this new kind of CQDs/P25 composite reaches 71%, which is approximately 1.65 times than that of the pure P25 at room temperature. The initial concentration of NO pollutants is 10 ppm. The photocatalytic efficiency of the composite catalyst achieves the highest when the content of CQDs is 1%. It can be concluded that the CQDs extend the light absorption range and adjust the band gap of pure P25. The high photocatalytic performance of this new kind of photocatalyst can be mainly attributed to the unique up-conversion fluorescence property, nanometer size effect and surface activity effect.
关键词： Composite catalyst,NO pollutant,CQDs,P25,Photocatalytic
更新于2025-09-12 10:27:22
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Bio-safety assessment of carbon quantum dots, N-doped and folic acid modified carbon quantum dots: A systemic comparison
摘要： The carbon quantum dots (CQDs) and their functionalized materials are promising in biomedical field because of their unique properties; meanwhile, a growing concern has been raised about the potential toxicity of these modified materials in biosystem. In this study, we synthesized original CQDs and two common functionalized CQDs including N-doped CQDs (NCQDs) and folic acid-modified CQDs (FA-CQDs), and compared the toxicity and biocompatibility with each other in vitro and in vivo. L929, C6 and normal cell MDCK were selected to detect the adverse reaction of these materials in vitro. No acute toxicity or obvious changes were noted from in vitro cytotoxicity studies with the dose of these CQD materials increasing to a high concentration at 1 mg/mL. Among these materials, the FA-CQDs show a much lower toxicity. Moreover, in vivo toxicity studies were performed on the nude mice for 15 days. The experimental animals in 10 or 15 mg/kg groups were similar with animals treated by phosphate buffer solution (PBS) after 15 days. The results of the multifarious biochemical parameters also suggest that the functionalized products of CQDs do not influence the biological indicators at feasible concentration. Our findings in vitro and in vivo through toxicity tests demonstrate that CQDs and their modified materials are safe for future biological applications.
关键词： Biodistribution,Functional materials,Biocompatibility,Fluorescence bioimaging,Carbon quantum dots (CQDs)
更新于2025-09-12 10:27:22
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All-solution-processed UV-IR broadband trilayer photodetectors with CsPbBr3 colloidal nanocrystals as carriers-extracting layer
摘要： Colloidal quantum dots (CQDs) are very promising nanomaterials for optoelectronics due to their tunable bandgap and quantum confinement effect. Especially, all-inorganic CsPbX3 (X=Br, Cl and I) perovskite nanocrystals (NCs) have attracted enormous interests owing to their promising and exciting applications in photovoltaic devices. In this paper, all-solution-processed broadband photodetectors ITO/ZnO/CsPbBr3/PbS/Au with high-performance were presented. The role of CsPbBr3 QDs layer as the carriers-extracting layer in the trilayer devices was discussed. As compared with bilayer device ITO/ZnO/PbS/Au, both the dark currents and photocurrents under illumination from UV-IR broadband trilayer photodetector ITO/ZnO(80nm)/PbS(150nm)/CsPbBr3(50nm)/Au are enhanced, but the trilayer photodetector ITO/ZnO(80nm)/CsPbBr3(50nm)/PbS(150nm)/Au showed a maximum specific detectivity (D*) of 1.73×1012 Jones with a responsivity (R) of 5.31 A/W under 6.8 mW/cm2 405 nm illumination. However, another trilayer photodetector ITO/ZnO(80nm)/PbS(150nm)/CsPbBr3(50nm)/Au showed a maximum D* of 8.3×1012 Jones with a R of 35 A/W under 1.6 mW/cm2 980 nm illumination. Further, the underlying mechanism for the enhanced performance of trilayer photodetectors was discussed. Thus, this strategy of all-solution-processed heterojunction configuration paves a facile way for broadband photodetectors with high-performance.
关键词： broadband photodetectors,all-solution-processed heterojunction,Colloidal quantum dots (CQDs),CsPbBr3 perovskite nanocrystals,carrier-extraction layer
更新于2025-09-12 10:27:22
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Facile preparation of high fluorescent carbon quantum dots from orange waste peels for nonlinear optical applications
摘要： A facile and eco‐friendly hydrothermal method was used to prepare carbon quantum dots (CQDs) using orange waste peels. The synthesized CQDs were well dispersed and the average diameter was 2.9 ± 0.5 nm. Functional group identification of the CQDs was confirmed by Fourier transform infrared spectrum analysis. Fluorescence properties of the synthesized CQDs exhibited blue emission. The fluorescence quantum yield of the CQDs was around 11.37% at an excitation wavelength of 330 nm. The higher order nonlinear optical properties were examined using a Z‐scan technique and a continuous wave laser that was operated at a wavelength of 532 nm. Results demonstrated that the synthesis of CQDs can be considered as promising for optical switching devices, bio‐scanning, and bio‐imaging for optoelectronic applications.
关键词： Z‐scan analysis,fluorescence quantum yield,CQDs,HR‐TEM,hydrothermal method
更新于2025-09-11 14:15:04
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A multifunctional sensor for selective and sensitive detection of vitamin B12 and tartrazine by F?rster resonance energy transfer
摘要： We used thiamine nitrate (TN) as single material to fabricate nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) with a quantum yield of 10.4% through one-pot hydrothermal method, and its properties were characterized by TEM, XPS, FTIR, fluorescence (FL) and UV-vis spectrophotometer, respectively. The fluorescence of N,S-CQDs was effectively quenched in the presence of vitamin B12 (VB12)/tartrazine due to F?rster resonance energy transfer (FRET). Moreover, the rate (KT) and efficiency (E%) of energy transfer from N,S-CQDs (as a donor) to VB12/tartrazine (as an acceptor) enhanced with increasing the concentrations of acceptor, and the KT and E% were also varied with the change of excitation wavelengths (from 338 to 408 nm). Based on this principle, a multifunctional fluorescence probe was designed for selective and sensitive detection of VB12/tartrazine with a detection limit (3σ/slope) of 15.6/18.0 nmol/L. Meanwhile, the proposed method was successfully employed to detect VB12/tartrazine in milk and several beverages with a recovery range of 97.5-104.2% /91.0-110.6%.
关键词： Tartrazine,Multifunctional sensor,FRET,N,S-CQDs,Vitamin B12
更新于2025-09-09 09:28:46
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Fabrication of highly efficient and hierarchical CdS QDs/CQDs/H-TiO2 ternary heterojunction: Surpassable photocatalysis under sun-like illumination
摘要： Highly efficient and durable visible-light utilized nanocomposites have a vital role in environmental pollutants remediation. Hence, in this study, we have fabricated CdS QDs co-sensitized CQDs/H-TiO2 (Hollow Titania) ternary heterostructures (CdS QDs/CQDs/H-TiO2) in a facile region-selective deposition route. The as-fabricated nanocomposites were evidently characterized by physicochemical techniques. CdS QDs were uniformly distributed on the smooth surface of hierarchical CQDs/H-TiO2 heterojunction. The as-fabricated CdS QDs/CQDs/H-TiO2 nanocomposite has high-performances for efficient degradation efficacy of phenol, MB and RhB which exhibited enhanced degradation activities with rate constants (k) of 0.03, 0.051 and 0.045 min-1, respectively. All these superior photocatalytic activities obviously attributed to the effect of calcination temperature, enhanced photocurrent, minimized recombination of photo-induced charges in the photocatalysis and optimum content of CdS QDs have the distinct basis for the close interfacial connection developing. In addition, evidenced on the arguable results of electron spin resonance and radical-trapping experiments, the primary reactive-oxygen species and a plausible reaction-mechanism for organic pollutants degradation over CdS QDs/CQDs/H-TiO2 were proposed. This creative work is strategically considered an important step to potentially enhance the utilization of TiO2 in various fields as visible light-induced heterojunction.
关键词： Hollow TiO2,CdS QDs/CQDs/H-TiO2,Visible-light photocatalysis,CQDs/H-TiO2,Environmental remediation
更新于2025-09-04 15:30:14