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A luminous off-on probe for the determination of 2,6-pyridinedicarboxylic acid as an anthrax biomarker based on water-soluble cadmium sulfide quantum dots
摘要： A fluorescence off-on sensing platform was developed based on thioglycolic acid-stabilized cadmium sulfide quantum dots (CdS QDs) as fluorescence probe for the sensitive and selective detection of 2,6-pyridinedicarboxylic acid (DPA) in spores. The fluorescence emission intensity of the quantum dots at 650 nm when excited at 460 nm was first quenched by mixing with europium ions (Eu3+) and then recovered after the addition of DPA. The interaction of DPA with Eu3+ relieved the quenching effect of Eu3+ toward CdS QDs. As the DPA concentration increases, the color of the probe changes from colorless to red. The method exhibits a wide linear range from 1 to 120 μM for DPA determination, with a detection limit of 0.2 μM. The CdS QDs based nanoprobe was successfully applied for sensitive determination of DPA released from bacteria spores. In this case, the detection limit is 3.5 × 104 CFU·mL?1.
关键词： Bacillus anthracis,CdS quantum dots,2, 6-Pyridinedicarboxylic acid,Bacteria spores,Fluorescence recovery
更新于2025-09-23 15:19:57
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Numerical analysis of CdS-CIGS interface configuration on the performances of Cu(In,Ga)Se2 solar cells
摘要： One dimension solar Cell Simulation package (SCAPS) is used to analyze the impact of the CdS-CIGS interface configuration on the performances of CIGS solar cells. We simulated the current-voltage characteristic of two models of the cell: one with a donor type defect (OVC model) and the other with acceptor type defect (P+ model) at the CdS-CIGS interface. The advantages and disadvantages of these CIGS surface configuration on the electrical parameters were discussed according to their thicknesses, defect density and carrier lifetime. The simulation results show that the model with the P+ layer has poor performance when its thickness and defect density increase, due to a huge distortion on the J-V characteristic. On the other hand, the OVC layer plays a fundamental role in the performance of CIGS solar cells. Better performances are obtained with the OVC model when the density of donor defect is in the range 1013 - 1015 cm-3, the charge carriers lifetime in the range 0.02 - 1 ns, and the thickness of the OVC layer in the range 200 - 400 nm.
关键词： P+ layer,OVC layer,SCAPS-1D,Distortion,CdS-CIGS interface
更新于2025-09-23 15:19:57
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Hybrid chemical bath deposition-CdS/sputter-Zn(O,S) alternative buffer for Cu <sub/>2</sub> ZnSn(S,Se) <sub/>4</sub> based solar cells
摘要： To replace the conventionally used CdS buffers in Cu2ZnSn(S,Se)4 (CZTSSe) based thin-film solar cells, sputtered Zn(O,S) buffer layers have been investigated. Zn(O,S) layers with three different [O]/([O] + [S]) ratios (0.4, 0.7, and 0.8)—and a combination of Zn(O,S) and CdS (“hybrid buffer layer”) were studied. In comparison to the CdS reference, the external quantum efficiency (EQE) of the Zn(O,S)-buffered devices increases in the short- and long-wavelength regions of the spectrum. However, the average EQE ranges below that of the CdS reference, and the devices show a low open-circuit voltage (VOC). By adding a very thin CdS layer (5 nm) between the absorber and the Zn(O,S) buffer, the VOC loss is completely avoided. Using thicker intermediate CdS layers result in a further device improvement, with VOC values above those of the CdS reference. X-ray photoelectron spectroscopy (XPS) measurements suggest that the thin CdS layer prevents damage to the absorber surface during the sputter deposition of the Zn(O,S) buffer. With the hybrid buffer configuration, a record VOC deficit, i.e., a minimum difference between bandgap energy Eg (divided by the elementary charge q) and VOC (Eg/q – VOC) of 519 mV could be obtained, i.e., the lowest value reported for kesterite solar cells to date. Thus, the hybrid buffer configuration is a promising approach to overcome one of the main bottlenecks of kesterite-based solar cells, while simultaneously also reducing the amount of cadmium needed in the device.
关键词： VOC deficit,Cu2ZnSn(S,Se)4,CdS,hybrid buffer layer,open-circuit voltage,X-ray photoelectron spectroscopy,thin-film solar cells,Zn(O,S) buffer layers,external quantum efficiency
更新于2025-09-23 15:19:57
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Facile incorporation of DNA-templated quantum dots for sensitive electrochemical detection of the oral cancer biomarker interleukin-8
摘要： Recent studies reveal a great value of interleukin-8 (IL-8), a pro-inflammatory cytokine, as a potent biomarker for early diagnosis of oral cancer. Herein, a new electrochemical method is proposed to detect IL-8 by facilely incorporating DNA-templated quantum dots (QDs). In principle, target IL-8 is first treated with the reducing agent tris(2-carboxyethyl)phosphine (TCEP) to yield active thiols and then captured by antibody-functionalized magnetic beads (MBs). Thereafter, via the Michael addition reaction between the active thiol and maleimide group, a maleimide-modified DNA probe is linked to the surface of MBs, which can initiate a process of rolling circle amplification. In this way, long-range DNA strands are generated on the MB surface, subsequently recruiting DNA-templated CdTe/CdS QDs (DNA-QDs) to act as electrochemical reporters. By tracing the responses of DNA-QDs, the method allows IL-8 detection in a linear range from 5 to 5000 fg/mL with a detection limit of 3.36 fg/mL. The selectivity, reproducibility, and applicability in complex serum samples are also demonstrated to be favorable, indicating that the method may have a great potential in the future. More importantly, the use of TCEP treatment in the method not only provides a facile way to incorporate DNA-QDs, avoiding the complicated and time-consuming preparation process of antibody-DNA conjugates or functional nanomaterials; but also makes the method capable of being extended to detect other protein biomarkers in view of widespread presence of disulfides, which may hold a broad potential to facilitate efficient biosensing designs.
关键词： Michael addition reaction,Oral cancer,Interleukin-8,Tris(2-carboxyethyl)phosphine,DNA-templated CdTe/CdS quantum dots
更新于2025-09-23 15:19:57
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A facile in situ growth of CdS quantum dots on covalent triazine-based frameworks for photocatalytic H2 production
摘要： CdS quantum dots (QDs) are excellent visible-light-driven photocatalysts due to their unique small size (<10 nm), suitable band energy structure, and short charge transportation length. Unfortunately, the easy aggregation of CdS QDs to form larger particles results in a higher recombination rate for photoinduced electron-hole pairs, which deteriorates the photocatalytic activity. Here, we report in situ growth of CdS QDs with high dispersion and stability on covalent triazine-based frameworks (CTFs) via a facile photoreduction method. The photocatalytic H2 evolution activity of CdS QD-loaded CTFs is effectively enhanced to approximately 55 and 4 times than that of pristine CTFs and bulk CdS, respectively. This enhanced photocatalytic performance is mainly ascribed to the higher separation rate of photogenerated carriers resulting from synergistic QD-on-sheet interactions between CdS QDs and CTFs. This work develops an efficient one-pot strategy to prepare metal-sulfide QDs with high dispersion and underlines the potential of utilizing CTFs as a suitable platform to develop efficient photocatalytic systems.
关键词： In situ growth,CdS QDs,Photocatalysis,Visible light,H2 evolution,Covalent triazine-based frameworks
更新于2025-09-23 15:19:57
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Synthesis, characterization and electrochemical properties of Cadmium sulfide -Reduced Graphene Oxide nanocomposites
摘要： Nowadays, research interest is speedily growing for fabrication of semiconductor metal sulfide nanoparticles. Proper optimization of process variables for the synthesis process can ensure tunable morphologies and distinct characteristics. Appropriate synthesis strategy can alter their electrical, optical and catalytic properties significantly. A simple, one step, the hydrothermal approach has been undertaken to prepare CdS/rGO nanocomposite here. This technique ensures fabrication of graphene-based nanocomposites with outstanding electro-catalytic characteristics using a facile route. The structural, morphological and the electrochemical properties of the synthesized sample were observed. Surface morphological features together with its phase was identified using FESEM, TEM, and XRD analysis. The crystalline phase of the synthesized sample was confirmed from the X-ray diffraction pattern. Surface functional groups of the synthesized sample were analyzed using the FTIR and FT-Raman analysis. The optical characterization of the CdS and CdS/rGO nanocomposite were examined. The FESEM and TEM images were used to illustrate the surface morphology and particle size of the CdS and CdS/rGO nanocomposite. The elemental composition of the synthesized sample was evaluated using EDAX analysis. In this research, the values for dielectric loss, dielectric constant, and resistivity and AC conductivity of the synthesized samples were determined. Thus, the overall electrochemical features of the prepared sample were evaluated. The results elucidated here showed that the synthesized sample can be used as potential electrode materials for supercapacitor ensuring high energy.
关键词： CdS/rGO,nanocomposite,Graphene,electrochemical studies
更新于2025-09-23 15:19:57
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Improved CdS QDSSCs with graphene and anatase-rutile TiO2 composite as photoanodes
摘要： In this paper, we developed a simple and convenient method for incorporating graphene with anatase-rutile TiO2 composite and applied it as photoanode to improve the photovoltaic performance of CdS QDSSCs. Our research indicated in a CdS QDSSC system, the photoelectric conversion efficiency (PCE) of anatase-rutile TiO2 (TGr0) composite photoanode was 86% higher than that rutile TiO2 NRs. We also found that the PCE increased first and then decreased with the change of graphene content after the graphene was introduced into the anatase-rutile TiO2 photoanode. When the ratio of optimized graphene/anatase TiO2 particles composite that spin-coated on rutile TiO2 NRs photoanode was 5%, we attained a maximum PCE of 2.20%, which was 178% and 50% higher than that pure TiO2 NRs (0.79%) and TGr0 (1.47%), respectively.
关键词： Anatase-rutile TiO2,CdS quantum dots,Graphene,Photovoltaic performance
更新于2025-09-23 15:19:57
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Nonlinear Optical Properties of CdS Semiconductor nanowires
摘要： In this work, we report on the nonlinear optical properties in single Cadmium sulfide nanowires (CdS NWs). The high qulity growth of CdS semiconductor nanowires were synthesized by chemical vapor deposition (CVD) method. The as-obtained products were characterized by X-ray diffraction (XRD) , Scanning electron microscopy (SEM), and the energy dispersive X-ray spectrom (EDS) was used to determine the specific elemental distribution and show purity of the CdS semiconductor nanowires . The excitation of femtosecond laser(800 nm, 50 fs, 80 MHz) was used to study the nonlinear optical properties of CdS nanowires, such as the Second Harmonic Generation(SHG) and optical waveguide effect. CdS NW has a second harmonic generation with a blue emission bands at a wavelength of 400 nm . Finally, based on the dark field image of the CCD taken and combined with the spectrum, it is proved that CdS NW has an optical waveguide effect.
关键词： Cadmium sulfide (CdS),Waveguide,nanowires (NWs),Second- Harmonic Generation (SHG),Chemical Vapor Deposition (CVD)
更新于2025-09-19 17:15:36
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Bi-component synergic effect in lily-like CdS/Cu <sub/>7</sub> S <sub/>4</sub> QDs for dye degradation
摘要： CdS has attracted extensive attention in the photocatalytic degradation of wastewater due to its relatively narrow bandgap and various microstructures. Previous reports have focused on CdS coupled with other semiconductors to reduce the photocorrosion and improve the photocatalytic performance. Herein, a 3D hierarchical CdS/Cu7S4 nanostructure was synthesized by cation exchange using lily-like CdS as template. The heterojunction material completely inherits the special skeleton of the template material and optimizes the nano-scale morphology, and achieves the transformation from nanometer structure to quantum dots (QDs). The introduction of Cu ions not only tuned the band gap of the composites to promote the utilization of solar photons, more importantly, Fenton-like catalysis was combined into the degradation process. Compared with the experiments of organic dye degradation under different illumination conditions, the degradability of the CdS/Cu7S4 QDs is greatly superior to pure CdS. Therefore, the constructed CdS/Cu7S4 QDs further realized the optimization of degradation performance by the synergic effect of photo-catalysis and Fenton-like catalysis.
关键词： Fenton-like catalysis,photocatalysis,CdS/Cu7S4,ion exchange,quantum dots,dye degradation
更新于2025-09-19 17:15:36
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One-pot synthesis of carbon dots co-doped with N and S: high quantum yield governed by molecular state and fluorescence detection of Ag <sup>+</sup>
摘要： Fluorescent carbon-based nanoparticles, called chronically as carbon dots (CDs), were synthesised from citric acid (CA) and 2-Aminothiophenol (2AT) via an N and S co-doped hydrothermal method. After a series of micro-structural characterisation, N and S elements could be sufficiently doped by means of the heteroatom in the CDs solution. The as-prepared CDs solution showed blue colour fluorescence with the highest QY of 78.6%, and study on the UV–visible and PL spectra further revealed that the outstanding fluorescence of as-prepared CDs mainly originates from the generated molecular fluorophores instead of the surface state. Owing to the strong fluorescence, the as-prepared CDs can be used as a sensing probe for the detection of Ag+ with high sensitivity and selectivity. However, the changes of fluorescence intensity exhibited the complex nature of the quenching mechanism due to the –SH and –NH2 groups on the fringes of carbonaceous cores or molecular fluorophores to aggregate into another fluorescent cores with the assistance of Ag+ ions, which promises a new approach for efficient detection of Ag+ for the application in industrial pollutants.
关键词： Ag+,N-CDs,S,quenching mechanism,molecular fluorophores,higher QYs
更新于2025-09-19 17:15:36