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Cell Imaging Using Two-Photon Excited CdS Fluorescent Quantum Dots Working within the Biological Window
摘要： In recent years, two-photon excited semiconductor quantum dots (QDs) have been the subject of intense investigation due to their long excitation wavelength which helps to achieve deeper penetration and higher image resolution in optical bioimaging. In this paper, water-soluble CdS QDs were synthesized using a hydrothermal method and applied to human liver hepatocellular carcinoma (HepG2) cells. The first-principles calculation suggested that the S-rich defected structure contributes to a narrower band gap compared to the pristine structure. The resulting fluorescence wavelength was significantly red shifted, which was attributed to the deep defect states emission. The large Stokes shifts (> 200 nm) of the QDs can eliminate the possible cross-talk between the excitation light and the emission light. Two-photon induced red fluorescence emission can avoid overlapping with the autofluorescence emission of biological samples. The uptake and cell viability measurements of the HepG2 cells showed a good biocompatibility and a low toxicity of CdS QDs. Two-photon excited scanning microscopy images revealed that the HepG2 cells incubated with CdS QDs emitted bright red upconversion fluorescence and the fluorescence brightness was 38.2 times of that of the control group. These results support CdS QDs as a good candidate for application in cellular imaging.
关键词： two-photon absorption,CdS quantum dots,deep defect states,HePG2 cells,biological imaging
更新于2025-11-21 11:24:58
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Coordination between Surface Lattice Resonances of Poly(glycidyl Methacrylate) Line Array and Surface Plasmon Resonances of CdS Quantum on Silicon Surface
摘要： In this work, a unique hybrid system is proposed for one-dimensional gratings comprising of poly(glycidyl methacrylate) (PGMA) brushes and CdS quantum dots (CQDs). Generally, the emission of QDs is too weak to be observed in a dry state. Plasmonic resonances of the grating structures can be used to enhance the light emission or absorption of CQDs. The interaction between PGMA plasmonic nanostructures and inorganic CQDs plays a crucial role in engineering the light harvest, notably for optoelectronic applications. Extinction measurements of the hybrid system consisting of a PGMA grating and CQDs are reported. We designed one-dimensional gratings with various resolutions to tune the absorptance peaks of grating. PGMA grating grafted from a 1.5 μm resolution of trench arrays of photoresist exhibited absorptance peak at 395 nm, close to the absorption peak of CQDs, resulting in the photoluminescence enhancement of CQDs on the grating due to high charge carriers’ recombination rate. Generally, the emission of quantum dots occurs under irradiation at characteristic wavelengths. Immobilizing QDs on the grating facilitates the emission of QDs under irradiation of full-wavelength light. Furthermore, the PGMA gratings with CQDs were immersed in various solvents to change the geometries resulting the shift of absorptance peak of grating. The proposed method could be applied for sensing the nature of the surrounding media and vice versa, as well as for various media of solvents.
关键词： one-dimensional grating,CdS quantum dots,PGMA brush
更新于2025-11-14 17:03:37
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Efficient All-Inorganic CsPbBr <sub/>3</sub> Perovskite Solar Cells by Using CdS/CdSe/CdS Quantum Dots as Intermediate Layers
摘要： Highly e?cient all-inorganic perovskite solar cells require a fast charge transfer from CsPbBr3 to TiO2 to reduce the recombination from trap states. Herein, we insert a CdS/CdSe/CdS quantum dot (QD) layer between the TiO2 and CsPbBr3 layers to fabricate all-inorganic perovskite solar cells. By tuning the thicknesses of the CdSe layer of CdS/CdSe/CdS QDs, the conduction band (CB) levels can be adjusted to -3.72~-3.87 eV. After inserting the QD intermediate layer, the energy o?set between the CB of TiO2 and CsPbBr3 is reduced, thus leading to a charge transfer rate boost from 0:040 × 109 to 0:059 × 109 s?1. The power conversion e?ciency (PCE) of the solar cell with QD intermediate layer achieves 8.64%, which is 20% higher than its counterpart without QDs.
关键词： CdS/CdSe/CdS quantum dots,power conversion efficiency,charge transfer,all-inorganic perovskite solar cells
更新于2025-09-23 15:21:01
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Mn-doped CdS quantum dots as sensitizers in solar cells
摘要： CdS and di?erent concentrations of Mn+2 doped CdS quantum dots are synthesized via simple chemical method on poly-vinyl alcohol matrix. The doped and undoped CdS quantum dots are characterized by using UV–Vis absorption spectroscopy, X-ray di?raction, and energy dispersive X-ray spectroscopy to revel the changes in optical and structural properties due to Mn doping. The synthesized quantum dots were used as sensitizing layer on a ZnO thin ?lm solar cell and tested under arti?cial illumination condition to obtain the current density-voltage characteristics. A signi?cantly higher e?ciency of about 2.09% was obtained for Mn doped CdS quantum dots compared to that of 1% e?ciency in pure CdS quantum dot sensitized solar cell.
关键词： Mn doping,CdS quantum dots,QDSSC
更新于2025-09-23 15:21:01
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Q-switched fiber laser based on CdS quantum dots as a saturable absorber
摘要： In this work, a Q-switched fiber laser is demonstrated using quantum dots (QDs) cadmium sulfide (CdS) as a saturable absorber (SA) in an erbium-doped fiber laser (EDFL) system. The QD CdS is synthesized via the microwave hydrothermal assisted method and embedded into polyvinyl alcohol (PVA). The QD CdS/PVA matrix film is sandwiched in between two fiber ferrules by a fiber adapter. The generation of Q-switched fiber laser having a repetition rate, a pulse width, and a peak-to-peak pulse duration of 75.19 kHz, 1.27 μs, and 13.32 μs, respectively. The maximum output power of 3.82 mW and maximum pulse energy of 50.8 nJ are obtained at the maximum pump power of 145.9 mW. The proposed design may add to the alternative material of Q-switched fiber laser generation, which gives a high stability output performance by using quantum dots material as a saturable absorber.
关键词： CdS Quantum Dots,erbium-doped fiber laser,microwave hydrothermal assisted method,saturable absorber,Q-switched fiber laser
更新于2025-09-23 15:19:57
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The transparent device of CdS quantum dots modified Cu2O/ZnO orderly nano array p-n junction towards the enhanced photovoltaic conversion
摘要： The transparent device of CdS QDs modified Cu2O/ZnO nano array p-n junction is prepared via simple continuous magnetron sputtering method and chemical deposition. The p-n junction device with good stability exhibits decent transparency of about ~80% in visible light, and evident photovoltaic response enhancement of about ~100 times than the unmodified sample, that can be mainly attributed to the CdS QDs with high QY can improve the visible light response, the p-n junction with self-photovoltage and the ZnO order arrays can improve the transport of the photon-generated carriers.
关键词： p-n junction,CdS quantum dots,Orderly nano array,Transparent device
更新于2025-09-23 15:19:57
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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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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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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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Supersandwich Nanowire/Quantum Dots Sensitization Structure-Based Photoelectrochemical a??Signal-Ona?? Platform for Ultrasensitive Detection of Thrombin
摘要： A new photoelectrochemical (PEC) “signal-on” sensing platform based on photoactive material Bi2O3-ZnO and CdS quantum dots (QDs) sensitizer were fabricated for ultrasensitive determination of thrombin by constructing supersandwich nanowires. The CdS/ZnO/Bi2O3 sensitization structure with excellent energy level arrangement remarkably improved photoelectric conversion efficiency due to efficient separation of electron-hole. Moreover, the DNA supersandwich nanowire is ingeniously synthesized in one step by simple dislocation hybridization, which could carry a large amount of sensitized material CdS QDs. More importantly, with Exo III-assisted multiple amplification, the proposed “signal-on” platform demonstrated a detection range of 10 fM to 1 μM with the detection limit of 1.41 fM for thrombin. Impressively, the PEC platform can successfully detect human serum samples with good accuracy. Above all, the CdS/ZnO/Bi2O3 sensitization photoelectric biosensing platform by using DNA nanowire in combination with Exo III-multiple amplification open new sensitized amplification paths for supersensitive biosensing and bioanalysis.
关键词： photoelectrochemical,CdS quantum dots,signal-on,thrombin detection,Bi2O3-ZnO,supersandwich nanowires,Exo III-assisted multiple amplification
更新于2025-09-19 17:13:59