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Synthesis of Colloidal Blue-Emitting InP/ZnS Core/Shell Quantum Dots with the Assistance of Copper Cations
摘要： Colloidal InP quantum dots (QDs) have been considered as one of the most promising candidates for the applications in display and bio-label due to intrinsic toxicity-free and high photoluminescence. On account of the uncontrollable nucleation and growth for the synthesis of InP, it remains a challenge to obtain high-quality blue-emitting InP QDs with uniform size distribution. Herein, we employ a novel synthetic approach for producing blue-emitting InP/ZnS core/shell QDs with the assistance of copper cations. The studies reveal that the copper ions could combine with phosphorus precursor to form hexagonal Cu3-xP nanocrystals, which competed with the nucleation process of InP QDs, resulting in the smaller sized InP QDs with blue photoluminescence emission. After the passivation of InP QDs with ZnS shell, the synthesized InP/ZnS core/shell QDs present bright blue emission (~425 nm) with photoluminescence quantum yield (PLQY) of ~25%, which is the shortest wavelength emission for InP QDs till now. This research provides a new way to synthesize ultra-small semiconductor nanocrystals.
关键词： InP/ZnS core/shell,blue-emitting,Colloidal InP quantum dots,photoluminescence quantum yield,copper cations
更新于2025-09-12 10:27:22
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Enhanced PEC performance of hematite photoanode coupled with bimetallic oxyhydroxide NiFeOOH through a simple electroless method
摘要： The oxygen evolution reaction (OER) is one important bottleneck in the development of economical photoelectrodes. Herein, we firstly prepared bimetallic oxyhydroxide NiFeOOH layer on Fe2O3 photoanode through a simple electroless ligand-regulated oxidation method in order to build highly-matched semiconductor/cocatalyst interface. Benefited from the accelerated OER kinetics and low overpotential of bimetallic oxyhydroxide NiFeOOH, the resultant Fe2O3/NiFeOOH core-shell with strongly-bound heterojunction interface possesses better visible light absorption, enhanced photocurrent density (1.83 mA/cm2 at 1.23 VRHE) and good stability than bare Fe2O3 and semi-FeOOH and NiOOH decorated Fe2O3 photoanodes. We believe this work provides a new pathway for designing high-quality contact interface of various photoelectrode/catalyst.
关键词： electroless ligand-regulated oxidation,photoelectrochemical water splitting,Fe2O3,core-shell nanorod arrays,NiFeOOH
更新于2025-09-12 10:27:22
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Record High External Quantum Efficiency of 19.2% Achieved in Light‐Emitting Diodes of Colloidal Quantum Wells Enabled by Hot‐Injection Shell Growth
摘要： Colloidal quantum wells (CQWs) are regarded as a highly promising class of optoelectronic materials, thanks to their unique excitonic characteristics of high extinction coefficients and ultranarrow emission bandwidths. Although the exploration of CQWs in light-emitting diodes (LEDs) is impressive, the performance of CQW-LEDs lags far behind other types of soft-material LEDs (e.g., organic LEDs, colloidal-quantum-dot LEDs, and perovskite LEDs). Herein, high-efficiency CQW-LEDs reaching close to the theoretical limit are reported. A key factor for this high performance is the exploitation of hot-injection shell (HIS) growth of CQWs, which enables a near-unity photoluminescence quantum yield (PLQY), reduces nonradiative channels, ensures smooth films, and enhances the stability. Remarkably, the PLQY remains 95% in solution and 87% in film despite rigorous cleaning. Through systematically understanding their shape-, composition-, and device-engineering, the CQW-LEDs using CdSe/Cd0.25Zn0.75S core/HIS CQWs exhibit a maximum external quantum efficiency of 19.2%. Additionally, a high luminance of 23 490 cd m?2, extremely saturated red color with the Commission Internationale de L’Eclairage (CIE) coordinates of (0.715, 0.283), and stable emission are obtained. The findings indicate that HIS-grown CQWs enable high-performance solution-processed LEDs, which may pave the path for future CQW-based display and lighting technologies.
关键词： core/shell structures,colloidal quantum wells,nanoplatelets,hot injection,light-emitting diodes
更新于2025-09-12 10:27:22
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TiO2 Coated ZnO Nanorods by Mist Chemical Vapor Deposition for Application as Photoanodes for Dye-Sensitized Solar Cells
摘要： In this study, a mist chemical vapor deposition method was applied to create a coating of titanium dioxide particles in order to fabricate ZnO/TiO2 core–shell nanostructures. The thin layers of titanium dioxide on the zinc oxide nanorods were uniform and con?rmed as pure anatase phase. The morphological, structural, optical and photoluminescence properties of the ZnO/TiO2 core–shell structures were in?uenced by coating time. For instance, the crystallinity of the titanium dioxide increased in accordance with an increase in the duration of the coating time. Additionally, the thickness of the titanium dioxide layer gradually increased with the coating time, resulting in an increased surface area. The transmittance of the arrayed ZnO/TiO2 core–shell structures was 65% after 15 min of coating. The obtained ZnO/TiO2 core–shell nanostructures demonstrated high potentiality to serve as photoanodes for application in dye-sensitized solar cells.
关键词： chemical bath deposition,titanium dioxide,core–shell nanorods,mist chemical vapor deposition,zinc oxide
更新于2025-09-12 10:27:22
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Controlled Detonation Synthesis of Nano Fe-based Oxides/ SiO2 Core-shell Composite Particles
摘要： Controlled detonation of emulsion Explosive and Hexogen (a kind of high explosive, for short, RDX) was performed to prepare Fe-based oxides/SiO2 nanoparticles. XRD (X-ray diffraction), TEM (Transmission electron microscope) and VSM (Vibrating sample magnetometer) experiments were performed to characterize and investigate the ingredients and phase structure of the granules, morphology, and distribution of the particles and the magnetism of the powders respectively. Results indicated that Fe/Urea complex detonation via emulsion explosives was advantageous to prepare Fe-based oxides/SiO2 core-shell powders, the inner FeO/Fe core was properly coated by a silica outer shell with the core size of around 50nm and shell thickness of around 5~10nm. And most of the raw detonation dust were converted into SiO2 coating Fe particles with the remained core-shell structure after proper thermal treatment. Raw powders obtained by RDX detonation presented weaker magnetism than that via emulsion explosives detonation, but which was substantially improved after thermal treatment.
关键词： Controlled detonation,Fe-based oxides/SiO2,Emulsion explosive,Core-shell Structure
更新于2025-09-12 10:27:22
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Interfacial growth of the optimal BiVO4 nanoparticles onto self-assembled WO3 nanoplates for efficient photoelectrochemical water splitting
摘要： Photoelectrochemical water splitting is the most efficient green engineering approach to convert the sun light into hydrogen energy. The formation of high surface area core-shell heterojunction with enhanced light-harvesting efficiency, elevated charge separation, and transport are key parameters in achieving the ideal water splitting performance of the photoanode. Herein, we demonstrate a first green engineering interfacial growth of the BiVO4 nanoparticles onto self-assembled WO3 nanoplates forming WO3/BiVO4 core-shell heterojunction for efficient PEC water splitting performance. The three different WO3 nanostructures (nanoplates, nanobricks, and stacked nanosheets) were self-assembled on fluorine doped tin oxide glass substrates via hydrothermal route at various pH (0.8–1.2) of the solutions. In comparison to nanobricks and stacked nanosheets, WO3 nanoplates displayed considerably elevated photocurrent density. Moreover, a simple and low cost green approach of modified chemical bath deposition technique was established for the optimal decoration of a BiVO4 nanoparticles on vertically aligned WO3 nanoplates. The boosted photoelectrochemical current density of 1.7 mA cm?2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination was achieved for the WO3/BiVO4 heterojunction which can be attributed to a suitable band alignment for the efficient charge transfer from BiVO4 to WO3, increased light harvesting capability of outer BiVO4 layer, and high charge transfer efficiency of WO3 nanoplates.
关键词： Green hydrogen,Photoelectrochemical water oxidation,WO3/BiVO4 heterojunction,Low cost,Core-shell
更新于2025-09-12 10:27:22
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ZnO@TiO2 Core Shell Nanorod Arrays with Tailored Structural, Electrical, and Optical Properties for Photovoltaic Application
摘要： ZnO has prominent electron transport and optical properties, beneficial for photovoltaic application, but its surface is prone to the formation of defects. To overcome this problem, we deposited nanostructured TiO2 thin film on ZnO nanorods to form a stable shell. ZnO nanorods synthesized by wet-chemistry are single crystals. Three different procedures for deposition of TiO2 were applied. The influence of preparation methods and parameters on the structure, morphology, electrical and optical properties were studied. Nanostructured TiO2 shells show different morphologies dependent on deposition methods: (1) separated nanoparticles (by pulsed laser deposition (PLD) in Ar), (2) a layer with nonhomogeneous thickness (by PLD in vacuum or DC reactive magnetron sputtering), and (3) a homogenous thin layer along the nanorods (by chemical deposition). Based on the structural study, we chose the preparation parameters to obtain an anatase structure of the TiO2 shell. Impedance spectroscopy shows pure electron conductivity that was considerably better in all the ZnO@TiO2 than in bare ZnO nanorods or TiO2 layers. The best conductivity among the studied samples and the lowest activation energy was observed for the sample with a chemically deposited TiO2 shell. Higher transparency in the visible part of spectrum was achieved for the sample with a homogenous TiO2 layer along the nanorods, then in the samples with a layer of varying thickness.
关键词： TiO2 thin film,optical properties,ZnO nanorods,chemical deposition,DC reactive magnetron sputtering,pulsed laser deposition,electrical properties,core–shell
更新于2025-09-12 10:27:22
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Solidification Behavior of YSZ@Ni Nanoparticles during Laser Cladding Process
摘要： In this study, yttria-stabilized zirconia (YSZ) nanoparticles with a core-shell structure (YSZ@Ni) were used to produce a YSZ/metal thermal barrier coating by the laser cladding process. The surface morphology, phase composition, and elemental distribution of the cladding layer were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS), respectively. Splashing of YSZ nanoparticles during the cladding process was reduced when they were encapsulated with nickel. It was found that primary phases of elliptically shaped YSZ and YSZ/(FeCr2O4) eutectic nanostructures formed in the center of the molten pool, whereas equiaxed YSZ crystals formed along the edges after the laser cladding. The results showed that aggregation of Ni was observed in the interlayer between the ceramic coating and the substrate. Ni-rich spheres were observed around the equiaxed YSZ crystals. Furthermore, the solidification behavior of YSZ@Ni core-shell nanoparticles was analyzed by studying the thermodynamics and kinetics.
关键词： laser cladding,YSZ@Ni nanoparticles,coating,core-shell structure,solidification behavior
更新于2025-09-12 10:27:22
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Controlling Surface Chemical Heterogeneities of Ultrasmall Fluorescent Core–Shell Silica Nanoparticles as Revealed by High-Performance Liquid Chromatography
摘要： Ultrasmall (diameter below 10 nm) fluorescent core?shell silica nanoparticles have garnered increasing attention in recent years as a result of their high brightness and favorable biodistribution properties important for applications including bioimaging and nanomedicine. Here, we present an in-depth study that provides new insights into the physical parameters that govern full covalent fluorescent dye encapsulation within the silica core of poly(ethylene glycol)-coated core?shell silica nanoparticles referred to as Cornell prime dots (C′ dots). We use a combination of high-performance liquid chromatography (HPLC), gel-permeation chromatography, and fluorescence correlation spectroscopy to monitor the result of ammonia concentration in the synthesis of C′ dots from negatively and positively charged versions of near-infrared dyes Cy5 and Cy5.5. HPLC, in particular, allows the distinction between cases of full versus partial dye encapsulation in the silica particle core leading to surface chemical heterogeneities in the form of hydrophobic surface patches, which, in turn, modulate biological response in ferroptotic cell death experiments. Our results demonstrate that there is a complex interplay between dye?dye and dye?silica cluster interactions originally formed in the sol?gel synthesis governing optimal dye encapsulation. We expect that the reduced surface chemical heterogeneities will make the resulting nanoparticles attractive for a number of applications in biology and medicine.
关键词： gel-permeation chromatography,ferroptotic cell death,high-performance liquid chromatography,fluorescent core?shell silica nanoparticles,fluorescence correlation spectroscopy
更新于2025-09-11 14:15:04
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Studies on the Effect of Acetate Ions on the Optical Properties of InP/ZnSeS Core/Shell Quantum Dots
摘要： The effect of residual acetate ions in indium oleate (In(OA)3) precursor on the photoluminescence quantum yield (PL QY) and size distribution of InP-based core/shell quantum dots (QDs) was studied. For comparison, the synthesis conditions of In(OA)3 were varied to control the amount of acetate ions that remained in the In(OA)3 precursor. The acetate ions resulted in smaller crystallites in single QD and in surfaces with a greater defect concentration, yielding low PL QYs and broader size distributions. For a complete exchange of acetate ligand in indium acetate (In(Ac)3) with oleate, In(Ac)3 was reacted with excess oleic acid. Pure In(OA)3 precursor led to bright InP/ZnSeS core/shell QDs with a uniform size after a shell was formed on the InP core QDs.
关键词： Core/shell,Indium phosphide,Quantum dots,Photoluminescence quantum yields
更新于2025-09-11 14:15:04