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Multi-mode photocatalytic performances of CdS QDs modified CdIn2S4/CdWO4 nanocomposites with high electron transfer ability
摘要： In general, quantum dots have the property of generating a plurality of charge carriers using hot electrons or using a single high-energy photon to improve the photocatalytic properties of the material. In this paper, CdS QDs@CdIn2S4/CdWO4 modified by CdS QDs was synthesized by the microwave-assisted hydrothermal method, and its composition, crystal structure, morphology, and surface physicochemical properties were well characterized. Electron microscopy results showed that CdS QDs@CdIn2S4/CdWO4 composite material exhibited a sheet structure with a length of ca. 350 nm and a width of ca. 50 nm, and CdS QDs uniformly distributes with a diameter of about 5 nm on the sheet structure. UV-visible diffuse reflectance tests showed that the combination of CdS QDs and CdIn2S4 can extend the light absorption range of CdWO4 to the visible region. Photoluminescence spectroscopy confirmed that CdS QDs had efficient electron transport capabilities. The multi-mode photocatalytic activity of CdS QDs@CdIn2S4/CdWO4 showed an excellent ability to degrade organic pollutants. Under the conditions of no co-catalyst and Na2S-Na2SO3 as the sacrificial agent, the hydrogen production of CdS QDs@CdIn2S4/CdWO4 can reach 221.3 μmol g?1 when exposed to visible light (λ > 420 nm) for 8 h.
关键词： CdS QDs,Quantum dots,Microwave-assisted hydrothermal method,CdWO4,Multimode photocatalysis,H2 evolution,CdIn2S4
更新于2025-09-10 09:29:36
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Amalgamation of N-graphene quantum dots with nanocubic like TiO2: an insight study of sunlight sensitive photocatalysis
摘要： In this work, a sunlight-sensitive photocatalyst of nanocubic-like titanium dioxide (TiO2) and N-doped graphene quantum dots (N-GQDs) is developed through a simple hydrothermal and physical mixing method. The successful amalgamation composite photocatalyst characteristics were comprehensively scrutinized through various physical and chemical analyses. A complete removal of bisphenol A (BPA) is attained by a synthesized composite after 30 min of sunlight irradiation as compared to pure TiO2. This clearly proved the unique contribution of N-GQDs that enhanced the ability of light harvesting especially under visible light and near-infrared region. This superior characteristic enables it to maximize the absorbance in the entire solar spectrum. However, the increase of N-GQDs weight percentage has created massive oxygen vacancies that suppress the generation of active radicals. This resulted in a longer duration for a complete removal of BPA as compared to lower weight percentage of N-GQDs. Hence, this finding can offer a new insight in developing effective sunlight-sensitive photocatalysts for various complex organic pollutants degradation.
关键词： Visible light,Near Infrared,Nanocubic-like TiO2,Bisphenol A,N-Graphene quantum dots,Sunlight
更新于2025-09-10 09:29:36
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-shell excitons studied using two-dimensional coherent spectroscopy
摘要： The dephasing mechanisms of p-shell and s-shell excitons in an InAs self-assembled quantum dot ensemble are examined using two-dimensional coherent spectroscopy (2DCS). 2DCS provides a comprehensive picture of how the energy level structure of dots affects the exciton dephasing rates and recombination lifetimes. We find that at low temperatures, dephasing of s-shell excitons is lifetime limited, whereas p-shell excitons exhibit significant pure dephasing due to scattering between degenerate spin states. At elevated temperatures, quadratic exciton-phonon coupling plays an important role in both s-shell and p-shell exciton dephasing. We show that multiple p-shell states are also responsible for stronger phonon dephasing for these transitions.
关键词： quantum dots,two-dimensional coherent spectroscopy,dephasing,InAs,exciton-phonon coupling
更新于2025-09-10 09:29:36
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[Advances in Experimental Medicine and Biology] Biomimetic Medical Materials Volume 1064 (From Nanotechnology to 3D Bioprinting) || Graphene-Based Nanomaterials and Their Applications in Biosensors
摘要： Graphene has been drawing tremendous attraction since the crystal graphene had been first observed by Novoselov in 2004 based on scotch-tape method (Novoselov et al. 2004). The name of the one-atom thick 2-D material, graphene is composed of two concepts, graphite and -ene. The thickness of graphene is the separation distance of the graphite, which is 0.335 nm recording the thinnest among all the nanomaterials developed until now. Graphene is 100–300 times stronger than steel with its Young’s modulus of 0.5–1.0 TPa and intrinsic strength of 130 GPa (Lee et al. 2008). The electron mobility at room temperature is 2.5 (cid:1) 105 cm2 V(cid:3)1 s(cid:3)1 (Mayorov et al. 2011) with tis maximum current density reaching a few million times larger than copper (Liu et al. 2007). The single atom thick crystal material has high thermal conductivity of 3000 WmK(cid:3)1 (Balandin et al. 2008) and high optical transmittance of 97.7% (Nair et al. 2008). Rightly these superb properties contributed Nobel Prize for Physics in 2010 and have been widely used for applications including sensors, electronics, energies and biology.
关键词： Electrochemical Detection,Graphene,Nanomaterials,Biosensors,Quantum Dots
更新于2025-09-10 09:29:36
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Wavelength-Tunable Band-Edge Photoluminescence of Nonstoichiometric Ag–In–S Nanoparticles via Ga <sup>3+</sup> Doping
摘要： The nonstoichiometry of I?III?VI semiconductor nanoparticles, especially the ratio of group I to group III elements, has been utilized to control their physicochemical properties. We report the solution-phase synthesis of non-stoichiometric Ag?In?S and Ag?In?Ga?S nanoparticles and results of the investigation of their photoluminescence (PL) properties in relation to their chemical compositions. While stoichiometric AgInS2 nanoparticles simply exhibited only a broad PL band originating from defect sites in the particles, a narrow band edge PL peak newly appeared with a decrease in the Ag fraction in the nonstoichiometric Ag?In?S nanoparticles. The relative PL intensity of this band edge emission with respect to the defect-site emission was optimal at a Ag/(Ag + In) value of ca. 0.4. The peak wavelength of the band edge emission was tunable from 610 to 500 nm by increased doping with Ga3+ into Ag?In?S nanoparticles due to an increase of the energy gap. Furthermore, surface coating of Ga3+-doped Ag?In?S nanoparticles, that is, Ag?In?Ga?S nanoparticles, with a GaSx shell drastically and selectively suppressed the broad defect-site PL peak and, at the same time, led to an increase in the PL quantum yield (QY) of the band edge emission peak. The optimal PL QY was 28% for Ag?In?Ga?S@GaSx core?shell particles, with green band-edge emission at 530 nm and a full width at half-maximum of 181 meV (41 nm). The observed wavelength tunability of the band-edge PL peak will facilitate possible use of these toxic-element-free I?III?VI-based nanoparticles in a wide area of applications.
关键词： band-edge photoluminescence,multinary semiconductor,quantum dots,nonstoichiometry,I?III?VI2 semiconductor,visible photoluminescence,wavelength tunability,semiconductor nanocrystals
更新于2025-09-10 09:29:36
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Evolution of the Ligand Shell around Small ZnO Nanoparticles during the Exchange of Acetate by Catechol: A Small Angle Scattering Study
摘要： The core-shell structure of colloids surrounded by ligands is of great importance for their later application as it can significantly alter the chemical and physical properties of the nanoparticles (NPs). A combination of small angle X-ray and neutron scattering (SAXS/SANS) the native solution with additional ex situ measurements (titration-UV) was applied to study the NP/ligand interface of ZnO NPs after functionalization with catechol derivatives. Based on SAXS data, it was found that within the multimodal particle size distribution the fraction of agglomerates is shifted to smaller sizes and nearly disappeared upon the binding of ethyl 3,4-dihydroxybenzoate (CAT) molecules. This is ascribed to improved stabilization at the primary particle level by CAT molecules. By combining the neutron scattering contrast with the input of bound CAT molecules from a previously developed titration-UV method, the heterogeneous composition of the ligand shell became accessible for the first time.
关键词： small angle scattering,quantum dots,in situ analysis,ligand exchange,core-shell
更新于2025-09-10 09:29:36
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14.2: <i>Invited Paper:</i> Quantum Yield Measurement Using Organic Dyes as References for Semiconductor Nanocrystals
摘要： A method of using series of organic dyes as reference to measure the quantum yield efficiency (QY) for semiconductor nanocrystals (Quantum Dots, QDs) in solution state is reported. In the proposed method, the sensitivity of the fluorescence spectrophotometer on wavelength as well as the excitation power intensity is considered to improve the accuracy.
关键词： Semiconductor Nanocrystals,Quantum Dots,QDs,Quantum Yield Efficiency Measurment
更新于2025-09-09 09:28:46
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Super-resolution enhancement by quantum image scanning microscopy
摘要： The principles of quantum optics have yielded a plethora of ideas to surpass the classical limitations of sensitivity and resolution in optical microscopy. While some ideas have been applied in proof-of-principle experiments, imaging a biological sample has remained challenging, mainly due to the inherently weak signal measured and the fragility of quantum states of light. In principle, however, these quantum protocols can add new information without sacrificing the classical information and can therefore enhance the capabilities of existing super-resolution techniques. Image scanning microscopy, a recent addition to the family of super-resolution methods, generates a robust resolution enhancement without reducing the signal level. Here, we introduce quantum image scanning microscopy: combining image scanning microscopy with the measurement of quantum photon correlation allows increasing the resolution of image scanning microscopy up to twofold, four times beyond the diffraction limit. We introduce the Q-ISM principle and obtain super-resolved optical images of a biological sample stained with fluorescent quantum dots using photon antibunching, a quantum effect, as a resolution-enhancing contrast mechanism.
关键词： image scanning microscopy,quantum dots,quantum optics,super-resolution microscopy,photon antibunching
更新于2025-09-09 09:28:46
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Molecularly imprinted polymer based hybrid structure SiO2@MPS-CdTe/CdS: A novel fluorescence probe for Hepatitis A Virus
摘要： A novel designed fluorescence molecularly imprinted polymer (MIP) probe made from CdTe/CdS quantum dot (QD)-based silica nanoparticles (SiO2@MPS-CdTe/CdS) was successfully created via a sol?gel process. The target virus - hepatitis A virus (HAV) was selectively captured by imprinted polymer layer, resulting in the fluorescence quenching of the QDs within 20 min, which could be explained by the energy transfer mechanism. Under optimized conditions, the limit of detection for the SiO2@MPS-CdTe/CdS MIP was as low as 88 pmol?L?1, and excellent linearity was obtained from 0.2 to 1.4 nM. Additionally, the nanosensor was successfully used to detect the HAV from a dilution of human serum, in which recoveries were in the range of 96.7%-103.8%. Overall, the current work proposes a novel and cost-effective method to synthesize SiO2@MPS-CdTe/CdS MIPs for use as a tool to rapidly and efficiently detect HAV, and it also provides promising perspectives to further advance virus imprinting research.
关键词： Hepatitis A Virus (HAV),Virus Molecularly Imprinted Polymer,Fluorescence Detection,Quantum Dots,Hybrid Structure
更新于2025-09-09 09:28:46
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Paper-Based Fluorescent Immunoassay for Highly Sensitive and Selective Detection of Norfloxacin in Milk at Picogram Level
摘要： Norfloxacin (NOR) in milk may influence mammalian cell replication and bring about a decrease in the efficiency for treating infection in humans. However, current techniques for detecting NOR usually require expensive instruments and trained personnel. In this work, we have developed a low-cost and simple method via paper-based fluorescent immunoassay for highly sensitive and selective detection of NOR in milk at picogram level. The NOR monoclonal antibody labeled with quantum dots is used as a detection probe to recognize the corresponding NOR, which can quantitatively detect NOR on paper-based devices. The detection limits in aqueous solution and milk are 1 pg/mL and 10 pg/mL, respectively. The developed paper-based method provides a cheap, sensitive, eco-friendly, and rapid approach for quantitative detection of trace NOR in milk, which may find wide applications in food safety inspection. Noteworthy, the method is especially suitable for applications at resource-limited and on-site settings.
关键词： Fluorescent immunoassay,Paper-based devices,Quantum dots,Norfloxacin,Milk
更新于2025-09-09 09:28:46