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A novel fluorescent probe for H2O2 detection based on CdSe@ZnS quantum dots/Ag nanocluster hybrid
摘要： The selective and quantitative detection of H2O2 is important for its employment in physiological, environmental and industrial applications. In this paper, a sensitive and selective strategy for H2O2 detection was established based on the fluorescence quenching of CdSe@ZnS quantum dots (QDs) by H2O2-mediated etching process of Ag nanoclusters (AgNCs). In this strategy, dihydrolipoic acid (DHLA) modified AgNCs were applied as H2O2 response group, the existence of H2O2 could initiate the oxidation of AgNCs and the production of Ag+, which could give rise to the effective fluorescence quenching of CdSe@ZnS QDs. Based on this strategy, the present fluorescent assay could realize the quantificational detection of H2O2 and the limit of detection is calculated to be 0.3 mM under the optimum conditions. Furthermore, CdSe@ZnS/AgNCs hybrid-based probe was applied to detecting H2O2 in milk samples and showed a good recoveries results ranged from 95.8% to 112.0%, meaning the potential applicability of this strategy.
关键词： H2O2 detection,Ag nanoclusters,Fluorescence quenching,CdSe@ZnS quantum dots
更新于2025-11-19 16:46:39
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Photophysical Properties of Multilayer Graphenea??Quantum Dots Hybrid Structures
摘要： Photoelectrical and photoluminescent properties of multilayer graphene (MLG)–quantum dots (QD) hybrid structures have been studied. It has been shown that the average rate of transfer from QDs to the MLG can be estimated via photoinduced processes on the QDs’ surfaces. A monolayer of CdSe QDs can double the photoresponse amplitude of multilayer graphene, without influencing its characteristic photoresponse time. It has been found that efficient charge or energy transfer from QDs to MLG with a rate higher than 3 × 108 s?1 strongly inhibits photoinduced processes on the QD surfaces and provides photostability for QD-based structures.
关键词： photophysical properties,CdSe–ZnS quantum dots,hybrid structures,photoelectrical properties,multilayered graphene,photoactivation
更新于2025-09-23 15:19:57
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Alleviating the toxicity of quantum dots to Phanerochaete chrysosporium by sodium hydrosulfide and cysteine
摘要： Quantum dots (QDs) have caused large challenges in clinical tests and biomedical applications due to their potential toxicity from nanosize effects and heavy metal components. In this study, the physiological responses of Phanerochaete chrysosporium (P. chrysosporium) to CdSe/ZnS QDs with either an inorganic sulfide NaHS or an organic sulfide cysteine as antidote have been investigated. Scanning electron microscope analysis showed that the hyphal structure and morphology of P. chrysosporium have obviously changed after exposure to 100 nM of COOH CdSe/ZnS 505, NH2 CdSe/ZnS 505, NH2 CdSe/ZnS 565, or NH2 CdSe/ZnS 625. Fourier transform infrared spectroscopy analysis indicated that the existence of hydroxyl, amino, and carboxyl groups on cell surface could possibly conduct the stabilization of QDs in an aqueous medium. However, after NaHS or cysteine treatment, the cell viability of P. chrysosporium exposed to CdSe/ZnS QDs increased as compared to control group, since NaHS and cysteine have assisted P. chrysosporium to alleviate oxidative damage by regulating lipid peroxidation and superoxide production. Meanwhile, NaHS and cysteine have also stimulated P. chrysosporium to produce more antioxidant enzymes (superoxide dismutase and catalase), which played significant roles in the defense system. In addition, NaHS and cysteine were used by P. chrysosporium as sulfide sources to promote the glutathione biosynthesis to relieve CdSe/ZnS QDs-induced oxidative stress. This work revealed that sulfide sources (NaHS and cysteine) exerted a strong positive effect in P. chrysosporium against the toxicity induced by CdSe/ZnS QDs.
关键词： Detoxification,Cysteine,CdSe/ZnS quantum dots,Sodium hydrosulfide,Antioxidant enzymes,Oxidative stress
更新于2025-09-23 15:19:57
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Solution-processed QD-LEDs in visible range: Modulation bandwidth enhancement
摘要： Light-emitting diodes based on quantum dots (QD-LEDs) have attracted much attention not only due to their usage in lighting and display applications but also as the light sources in visible light communication (VLC). One of the most important parameters of a QD-LED as a light source is the improvement of modulation bandwidth in order to increase the data transfer rate. Here, three sets of QD-LEDs are presented for which some parameters such as frequency response are investigated, once for the devices with similar structure but different homogeneities and then for those with minor changes in the structure. It was found that by changing the homogeneity of QDs in the same structure based on CdSe/ZnS and using the ZnO shell instead of ZnS, the modulation bandwidth varied between 2 and 8 MHz. Furthermore, for the structure based on CdSe/ZnS, the modulation bandwidth of 8 MHz is achieved which is fairly a wide bandwidth for a QD-LED. The idea of manipulation in the structure of nanomaterials can be an important step toward increasing the modulation bandwidth. According to calculated results, the carrier density in different layers is calculated and then the recombination current-voltage characteristics are compared with the experimental results, indicating high conformity.
关键词： Light emitting diode,Frequency response,CdSe/ZnS,Quantum dots,Modulation bandwidth
更新于2025-09-16 10:30:52
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Facile and efficient 3-chlorophenol sensor development based on photolumenescent core-shell CdSe/ZnS quantum dots
摘要： Quantum dots (QDs) are semiconducting inorganic nanoparticles, tiny molecules of 2–10 nm sizes to strength the quantum confinements of electrons. The QDs are good enough to emit light onto electrons for exciting and returning to the ground state. Here, CdSe/ZnS core/shell QDs have been prepared and applied for electrochemical sensor development in this approach. Flat glassy carbon electrode (GCE) was coated with CdSe/ZnS QDs as very thin uniform layer to result of the selective and efficient sensor of 3-CP (3-chlorophenol). The significant analytical parameters were calculated from the calibration plot such as sensitivity (3.6392 μA μM?1 cm?2) and detection limit (26.09 ± 1.30 pM) with CdSe/ZnS/GCE sensor probe by electrochemical approach. The calibration curve was fitted with the regression co-efficient r2 = 0.9906 in the range of 0.1 nM ～ 0.1 mM concentration, which denoted as linear dynamic range (LDR). Besides these, it was performed the reproducibility in short response time and successfully validated the fabricated sensor for 3-CP in the real environmental and extracted samples. It is introduced as a noble route to detect the environmental phenolic contaminants using CdSe/ZnS QDs modified sensor by electrochemical method for the safety of healthcare and environmental fields at broad scales.
关键词： CdSe/ZnS,Quantum dots,electrochemical sensor,3-chlorophenol,environmental safety
更新于2025-09-16 10:30:52
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Metal-enhanced fluorescence of interlaminar composite film with self-assembled quantum Dots/Au@SiO2 microarchitecture
摘要： Quantum dots fluorescence-enhanced films, which mainly consisted of CdSe@ZnS quantum dots and noble metal nanoparticles or nanorods, were formed by layer-by-layer self-assembly techniques. This particular architecture consisting of metal nanoparticles-poly (diallyl dimethylammonium chloride) (PDDA)-QDs was characterized by those fabrication processes mainly including surface-modifying the oleic acid-capped CdSe@ZnS QDs ( high quantum yield of ~89% ) with mercaptopropionic acid (MPA) to be charged negatively (-COO-) for following solution-processed assembly, adjusting the size and coating the gold nanoparticles/nanorods with silica to form suitable dielectric insulation layer and further optimize the fluorescence-enhanced performance, as well as using the cationic polyelectrolyte to control the charges between layers and form opposite charges between two adjacent layers. After optimizing the structure of the quantum dot fluorescence-enhanced films and corresponding surface plasmon enhancement effect, the enhancement factor of 10.8 in Au NPs@SiO2-PDDA-QDs complex film and that of 24.7 in Au NRs@SiO2-PDDA-QDs complex film as compared with the pure quantum dot fluorescence film were achieved, respectively. This indicated that the Au NRs@SiO2-PDDA-QDs complex film was one of the most promising potentials for further display backlight and biometric identifier application.
关键词： CdSe@ZnS quantum dots,Au@SiO2 microarchitecture,electrostatic self-assembly,metal surface plasmon enhancement,Quantum dots fluorescence-enhanced films
更新于2025-09-12 10:27:22
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Effect of energy transfer on the optical properties of surface-passivated perovskite films with CdSe/ZnS quantum dots
摘要： Surface passivation is an effective method to protect the surfaces and improve the luminescence properties of perovskite (PS) films. CdSe/ZnS core-shell quantum dots (QDs) have been employed for surface passivation of PS films because of their size-dependent tunable bandgaps. Herein, the energy transfer (ET) behavior of CH3NH3PbI2Br PS films covered with CdSe/ZnS QDs (QD/PS hybrid structures) is characterized by using photoluminescence (PL) and time-resolved PL spectroscopy. The PL decay time and the integrated PL intensity of the QD/PS hybrid structure increase compared with those of the bare PS films, owing to ET from the QDs to the PS and reduced charge traps. The ET efficiency increases from ~7% to 63% for the QD/PS hybrid structure when the core diameter of the QDs decreases from 6.5 to 2.7 nm, respectively. This can be explained by the charge transfer rate enhancement due to the control of energy level alignment of QDs. These results allow us to understand fundamental mechanisms such as ET from QDs to PS films as a function of the size of the QD.
关键词： CdSe/ZnS quantum dots,perovskite films,energy transfer,photoluminescence,surface passivation
更新于2025-09-12 10:27:22
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Photoinduced Modulation of the Emission from СdSe/ZnS Quantum Dots by Photochromic Transformations of Diarylethenes
摘要： A spectral study of the interaction between the molecules of photochromic compounds of the diarylethene class and CdSe/ZnS quantum dots (QDs), in dependence of the structure and nature of functional substituents of photochromes, has been performed. It is shown that both chemical and physical interactions are accompanied by photoinduced modulation of QD emission as a result of photochromic transformations of diarylethenes caused by the inductive transfer of excitation energy from QDs to the diarylethene cyclic isomer.
关键词： diarylethenes,CdSe/ZnS quantum dots,nanomaterials,photoinduced modulation,photochromic transformations,ceramics
更新于2025-09-12 10:27:22