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Anionic Quantum Dots reveal actin-microridges in zebrafish epidermis
摘要： Enhancement of the aqueous solubility and functionalization of CdTe-QDs (Quantum Dots) via surface modifications have made them suitable to be used as specific probes for cell imaging. Applications for targeting cell surfaces have been widely demonstrated in vitro but their use in animal models is not trivial. Here, we reported the interaction of mercaptosuccinic-coated (MSA) CdTe-QDs with the epidermis of living and Carnoy-fixed zebrafish embryos, providing a faster approach compared with immunodetection or standard Phalloidin staining of actin for visualization by fluorescence microscopy. In our study, labeling with anionic QDs is attained within minutes at nanomolar concentrations in whole mounted Carnoy-fixed zebrafish embryos, providing a faster approach compared with immunodetection or standard Phalloidin staining of actin for visualization by fluorescence microscopy. QDs concentrate along adherent junctions and reveal the characteristic pattern of actin microridges at the apical surface of the enveloping layer.
关键词： actin-microridges,anionic quantum dots,zebrafish epidermis
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Evaluation of Unauthorization at the Express-Control of Heating of Natural Gas
摘要： Light emitting devices based on Si quantum dots/SiO2 multilayers with dot size of 2.5 nm have been prepared. Bright white light emission is achieved under the dc driving conditions and the turn-on voltage of the device is as low as 5 V. The frequency-dependent electroluminescence intensity was observed under ac conditions of square and sinusoidal wave. It was found that the emission wavelength changes with frequency when sinusoidal ac is applied. The degradation of emission intensity is less than 12% after 3 h for ac driving condition, exhibiting the better device stability compared to the dc driving one.
关键词： electroluminescence (EL),Direct current (dc),Si quantum dots (Si QDs),frequency dependent
更新于2025-09-23 15:21:01
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Regulatory Preparation of N/S Doped Carbon Quantum Dots and Their Applications as Fe(III) Ion Sensors
摘要： The nitrogen-sulfur co-doped fluorescent carbon quantum dots (N/S-CQDs) were synthesized from sulfanilic acid. The fluorescence emission was independent of the excitation wavelength. In this experiment, the carbonization degree of the precursors was adjusted by solvent-thermal method to affect the sp2 conjugated dimension of CQDs, thus affecting the fluorescence performance of CQDs. They are well dispersed in water and ethanol, and have high selectivity for Fe3 +. The detection range is 0.025 ～ 0.4 mmol/L, and the detection limit is about 2.549 μmol/L. The CQDs prepared in this experiment emit light indirectly through the surface defect state. When CQDs is illuminated by light, the carriers generated by photons will emit light at a very fast speed due to the surface defect state, so the excited electrons in CQDs can be easily transferred to Fe3 +, making the surface of CQDs more complete, thus leading to the quenching of CQDs fluorescence.
关键词： Fe3 + sensor,Nitrogen and sulfur co-doping,carbon quantum dots,Fluorescence
更新于2025-09-23 15:21:01
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Introducing New Conjugated Quantum Dots for Photothermal Therapy in Biological Applications
摘要： It is well-known that near-infrared (NIR) light sources are appropriate to ablate benign tumor irreversibly using heat treatment even in deep tissues. The laser light penetration into the skin in these wavelengths is deep (3–5 mm). Applying new stable materials for emitting NIR wavelengths in tumor positions can help cancer treatment. In this paper, synthesis of the conjugated core-multishell Ag/SiO2/Ag and Au/SiO2/Au quantum dots (QDs) with indocyanine green (ICG) is done and their theoretical and experimental absorptions and emissions in the NIR region are investigated. Thus, heat generation (high-resolution medical imaging capabilities) and emission enhancement are explained and described based on the FRET model for the proposed core-multishell QDs and it is shown that Ag/SiO2/Ag with ICG presents 4 times higher emission rate versus ICG alone in NIR region. Also, because of the plasmon hybridization and also resonance light penetration enhancement, the temperature in tissues increases that is useful for photothermal therapy and NIR high-resolution medical imaging for deep tissues. As an alternative application, these nanoparticles with amazing features are used as a heat source in cancer treatment for shallow and deep tissues. Finally, it is shown that Ag/SiO2/Ag QDs are the best solution for this purpose.
关键词： Cancer detection,FRET,Imaging,Quantum dots,Photothermal therapy
更新于2025-09-23 15:21:01
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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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Multi-wavelength colloidal quantum dot lasers in distributed feedback cavities
摘要： Lasers with multi-wavelength colloidal quantum dots (CQDs) can be achieved using complex grating structures and ?exible substrate. The structure contains graduated periods and rectangular cavity fabricated through interference lithography, which acts as the distributed feedback cavity. A layer of densely packed CQD ?lm is deposited on the cavity via spin coating technique. The performance of CQD lasers based on di?erent distributed feedback cavities is investigated. Multi-wavelength lasing is achieved based on a ?exible rectangular cavity.
关键词： ?exible,tunable,distributed feedback,quantum dots lasers,multi-wavelength
更新于2025-09-23 15:21:01
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Facet Control for Trap-State Suppression in Colloidal Quantum Dot Solids
摘要： Trap states in colloidal quantum dot (QD) solids significantly affect the performance of QD solar cells, because they limit the open-circuit voltage and short circuit current. The {100} facets of PbS QDs are important origins of trap states due to their weak or missing passivation. However, previous investigations focused on synthesis, ligand exchange, or passivation approaches and ignored the control of {100} facets for a given dot size. Herein, trap states are suppressed from the source via facet control of PbS QDs. The {100} facets of ≈3 nm PbS QDs are minimized by tuning the balance between the growth kinetics and thermodynamics in the synthesis. The PbS QDs synthesized at a relatively low temperature with a high oversaturation follow a kinetics-dominated growth, producing nearly octahedral nanoparticles terminated mostly by {111} facets. In contrast, the PbS QDs synthesized at a relatively high temperature follow a thermodynamics-dominated growth. Thus, a spherical shape is preferred, producing truncated octahedral nanoparticles with more {100} facets. Compared to PbS QDs from thermodynamics-dominated growth, the PbS QDs with less {100} facets show fewer trap states in the QD solids, leading to a better photovoltaic device performance with a power conversion efficiency of 11.5%.
关键词： solar cells,trap-state suppression,quantum dots,facet control
更新于2025-09-23 15:21:01
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Plasmonic Hot-Electron-Induced Control of Emission Intensity and Dynamics of Visible and Infrared Semiconductor Quantum Dots
摘要： Plasmonic hot-electron-assisted control of emission intensities and dynamics of CdSe/ZnS and infrared PbS quantum dots are studied. This is done by exploring the impact of Au/Si and Ag/Si Schottky junctions on the decay rates of such quantum dots when these junctions are placed in close vicinity of a Si/Al oxide charge barrier, forming metal-oxide plasmonic metafilms. Such structures are used to investigate how metal-dependent distributions of hot electrons and their capture via Schottky junctions can lead to suppression of the defect environments of quantum dots, offering a novel platform wherein off-resonant (non-Purcell) plasmonic processes are used to control exciton dynamics. These results show that Ag metafilms can enhance the emission of CdSe/ZnS quantum dots and elongate their lifetimes more than Au metafilms. This highlights the more efficient nature of Ag/Si Schottky junctions for hot electron excitation and capture. These results also show that such junctions can significantly suppress the nonradiative decay rates of PbS quantum dots at frequencies far from the plasmon resonances. These results demonstrate a field-effect passivation of quantum dot defects via entrapment of hot electrons and control of emission intensities and dynamics of quantum dots via the nearly frequency-independent electrostatic field of such electrons.
关键词： hot electrons,passivation,quantum dots,plasmons,metal oxide
更新于2025-09-23 15:21:01
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Nitrogen-doped Graphene Quantum Dots for Remarkable Solar Hydrogen Production
摘要： We synthesized nitrogen (N)-doped graphene quantum dots (N-GQDs) using a top-down hydrothermal cutting approach. The concentration of N dopants was readily controlled by adjusting the concentration of the N source of urea. When N dopants were incorporated into GQDs, visible absorption was induced by C-N bonds, which created another pathway for generating photoluminescence (PL). Time-resolved PL data revealed that the carrier lifetime of GQDs was increased upon doping with the optimized N concentration. The photoelectrochemical properties of N-GQDs towards water splitting were studied, and the results showed that 2N-GQDs prepared with 2 g of urea produced the highest photocurrent. The photocatalytic activity of 2N-GQDs powder photocatalyst for hydrogen production was also examined under AM 1.5G illumination, showing substantial enhancement over that of pristine GQDs. Electrochemical impedance spectroscopy data further revealed a significant improvement in charge dynamics and reaction kinetics, and an increased carrier concentration as a result of N doping.
关键词： Solar Hydrogen Production,Charge Dynamics,Water Splitting,Graphene Quantum Dots,Nitrogen-doped
更新于2025-09-23 15:21:01
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Surface Regulation of CsPbBr <sub/>3</sub> Quantum Dots for Standard Blue-Emission with Boosted PLQY
摘要： It is demonstrated that, via surface treatment of CsPbBr3 perovskite quantum dots (PeQDs) by introducing small amount of organic ammonium chlorides possessing short alkyl chain (C ≤ 4) in methyl acetate in the typical purification process, the emission can be tuned from green to blue region with boosted photoluminescence quantum yield (PLQY). The Cl? mainly works on the surface of PeQDs to fill bromide vacancy, which generates a passivated mixed-halide surface and avoids formation of defects deep within bandgap. Meanwhile, the replacement of initial long-chain ligands with short chain ammonium moiety benefits the film PLQY. Accordingly, a standard blue emission of 461 nm with a high film PLQY of 52% is accessed and the corresponding colloidal shows a PLQY of 80% at 456 nm. This method is also proved to be a versatile tool to boost the PLQY of PeQDs by using short chain ammonium halides bearing the same X with the initial CsPbX3. A near-unity colloidal PLQY of 97% and 98% is achieved for CsPbBr3 and CsPbI3 respectively. Quantum dots light-emitting diode (QLED) with treated CsPbBr3 affords a standard blue electroluminescence of 459 nm and a maximum external quantum efficiency of 0.3%.
关键词： perovskite quantum dots,vacancy passivation,surface regulation,standard blue emission
更新于2025-09-23 15:21:01