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On-substrate porous-anodic-alumina-assisted gold nanostructure arrays: Meeting the challenges of various sizes and interfaces
摘要： Arrays of 0- and 1-dimentional noble-metal nanostructures aligned on solid substrates are in demand for nanocatalysis, bio- and optical sensing, or biomolecular analysis. Here we introduce a range of advances based on a systematic research towards the porous-anodic-alumina (PAA)-assisted on- substrate arrays of gold nanostructures, such as rods and spheres, spatially-separated and highly aligned on a metal or semiconductor supporting layer via a blend of the anodizing, re-anodizing, and post- anodizing treatments applied to a thin layer of Al superimposed on selected valve metals (W, Ti, Hf), metal bilayers (W/Ti), or binary metal alloy layers (W-Ti). The achievements are due to (1) the improved self-organization in the PAA thin films during the self-localizing high-current anodization of the upper Al layer at challenging potentials ranging 100 to 250 V and 20 to 5 V, and (2) the enhanced penetration of the alumina barrier layer by the undergrowing metal oxide due to the increasing polarization (re- anodizing). The protrusions of the undergrown metal oxide can be either selectively dissolved away providing perfect nanoholes in the alumina barrier layer or left as formed in the barrier layer and annealed in vacuum to increase their electron conductance and serve as the supports for subsequent metal electrodeposition. Additionally, the in-situ amplitude-modulated constant-current pulse deposition mode combined with the original surface-wiping technique to remove the overdeposited gold allow for smooth nucleation and uniform finishing of perfect arrays of on-substrate gold nanospheres and nanorods, having diameters from 10 to over 250 nm and length up to 2.5 ?m.
关键词： gold nanorods,electrodeposition,barrier layer dissolution,nanodots,porous anodic alumina
更新于2025-09-10 09:29:36
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Synthesis and magnetic properties of Fe-doped CdS nanorods
摘要： Hexagonal CdS and Fe-doped CdS nanorods were synthesized by a facile hydrothermal method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, UV-vis absorption, photoluminescence and X-ray photoelectron spectroscopy. The magnetic properties of undoped and Fe-doped CdS nanorods were investigated at room temperature. The experimental results demonstrate that the ferromagnetism of the Fe-doped CdS nanorods differ from that of the undoped CdS nanorods. The remanence magnetization (Mr) and the coercive field (Hc) of the Fe-doped CdS nanorods were 4.9×10-3 emu/g and 270.6 Oe, respectively, while photoluminescence properties were not influenced by doping. First-principle calculations show that the ferromagnetism in Fe-doped CdS nanocrystal arose not only from the Fe dopants but also from the Cd vacancies, although the main contribution was due to the Fe dopants.
关键词： hydrothermal synthesis,CdS nanorods,Fe doping,magnetic properties,photoluminescence
更新于2025-09-10 09:29:36
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Fabrication of novel 1D/2D V2O5/g-C3N4 composites as Z-scheme photocatalysts for CR degradation and Cr (VI) reduction under sunlight irradiation
摘要： Photocatalytic materials for environmental remediation of organic pollutants and heavy metals require not only a strong visible light response and high photocatalytic performance, but also the regeneration and reuse of catalysts. In this work, 1D/2D V2O5 nanorods/g-C3N4 nanosheets (VONRs/CNNs) composites were prepared by a facile impregnation method and employed in the degradation of a Congo red (CR) and reduction of Cr (VI) under sunlight irradiation. The as-prepared samples were studied by several characterization techniques including XRD, SEM, TEM, EDS, XPS, FTIR, UV-vis DRS and PL. Results revealed that the interface interaction between VONRs and CNNs was recognized via V2O5 nanorods loading on the surface of g-C3N4 nanosheets, improving the separation and transfer of photogenerated electron-hole pairs and restraining the recombination rate of charge carriers. As a result, the photocatalytic activity of the composites was enhanced in comparison with pure CNNs and VONRs. The photocatalytic efficiency of optimal composite (4-VONRs/CNNs) for the removal of CR (Cr (VI)) was about 9.33 (4.22) and 73.52 (19.2) times higher than that of pure CNNs and VONRs, respectively. Meanwhile, the 4-VONRs/CNNs exhibited good photocatalytic stability in recycling experiments. Such enormous enhancement in photocatalytic performance was predominantly ascribed to the efficient separation and transfer of photogenerated electron-hole pairs at the VONRs/CNNs interface imparted through the direct Z-scheme charge carrier migration mechanism. Moreover, the energy band structure and the quenching effects of different scavengers demonstrated that the electrons of CNNs and holes of VONRs with higher oxidizability and reducibility are the real participants in photocatalytic reactions.
关键词： g-C3N4 nanosheets,Z-scheme mechanism,Composites,Photocatalytic activity,V2O5 nanorods,1D/2D heterojunction
更新于2025-09-10 09:29:36
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Synthesis of ultra-narrow PbTe nanorods with extremely strong quantum confinement
摘要： Monodisperse, high-quality, ultra-narrow PbTe nanorods were synthesized for the first time in a one-pot, hot-injection reaction using trans-2-decenoic acid as the agents for lead precursors and tris(diethylamino)phosphine as the telluride precursors. High monomer reactivity, rapid nucleation and fast growth rate derived from the new precursors led to the anisotropic growth of PbTe nanocrystals at low reaction temperatures (< 150 oC). In addition, the aspect ratio of PbTe nanorods could be largely adjusted from 4 to 15 by tuning the Pb to Te precursor molar ratio and reaction temperatures. Moreover, the synthesized ultra-narrow PbTe nanorods exhibited extremely strong quantum confinement and presented unique optical properties. We revealed that the diameter and length of PbTe nanorods could significantly affect their optical properties, which potentially offer them new opportunities in the application of optoelectronic and thermoelectric devices and make them desired subjects for multiple exciton generation and other fundamental physics studies.
关键词： optical properties,PbTe nanorods,Colloidal semiconductor nanocrystals
更新于2025-09-10 09:29:36
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Solvent-Assisted Tuning the Size and Shape of CsPbBr3 Nanocrystals via Re-Dispersion Process at Ambient Condition
摘要： All-inorganic CsPbBr3 perovskite nanocrystals are emerging as a new class of semiconductors with outstanding optoelectronic properties and great potential for various applications, such as, lasing, photon detection, photovoltaics etc. This article provides the effect of solvents on the re-precipitation of CsPbBr3 perovskite at room temperature. The results observed for CsPbBr3 perovskite in various anti-solvent showed various cubes (nano to micro size), self-assembly of nanocubes and nanorods. In addition, all the various size (nano to micro), self-assembly of nanocubes and shape-controlled nanorods exhibited band-gap tuning at the green light region. The corresponding microscopy (FE-SEM and HR-TEM) images and photoluminescence quantum yield as well as lifetime decay are presented. To the best of our literature knowledge this is the first report on various solvent assisted studies on CsPbBr3 perovskite nanocrystals.
关键词： CsPbBr3 Nanocrystals,nanocubes,effect of solvents,lifetime decay,nanorods,self-assembly
更新于2025-09-10 09:29:36
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Fabrication of Gold Nanorods for SERS Detection of Thiabendazole in Apple
摘要： Thiabendazole (TBZ) is a kind of pesticide that is widely used in agriculture, and its residue may pose a threat to human health. In order to measure TBZ residues in food samples, a surface-enhanced Raman spectroscopy (SERS) method combined with a homogeneous and reusable gold nanorods (GNR) array substrate was proposed. GNR with a high uniformity was synthesized and then applied to the self-assembly of a GNR vertically aligned array. The relative standard deviation (RSD) of the array for SERS could reach 15.4%, and the array could be reused for more than seven times through the treatment of plasma etching. A logarithmic correlation between TBZ concentration and Raman intensity was obtained, with the best determination coefficient (R2) and the corresponding limit of detection (LOD) of 0.991 and 0.037 mg/L in methanol solution, and 0.980 and 0.06 ppm in apple samples, respectively. The recoveries of TBZ in apple samples ranged from 76% to 107%. This study provided a rapid and sensitive approach for detecting TBZ in apples based on SERS coupled with GNR array substrate, showing great potential for analyzing other trace contaminants in food.
关键词： Apple,Gold nanorods array,Surface enhanced Raman spectroscopy,Thiabendazole
更新于2025-09-10 09:29:36
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Effect of Catalysts on Hydrothermal Preparation of boron nitride nanostructures
摘要： Boron nitride (BN) has attracted intense interests due to its excellent thermal conductivity and electrical insulation, which make it a promising thermal interface material for electronic packaging. Conventionally, the BN nanostructures were made from high cost method, e.g. chemical vapor deposition (CVD), which was restricted by the extremely high reaction temperature as well as the expensive instruments. Herein, a facile hydrothermal method was presented, where the catalysts were used to tune the phase and morphologies of the BN products starting from the boron and nitrogen sources. With different catalysts, the phase of the products could be changed from the orthorhombic to cubic BN, and the morphology underwent an evolution from nanorods to nanoflowers. The results are of great significance for the large-scale fabrication of BN nanostructures in a low cost.
关键词： Nanoflowers,Hydrothermal synthesis,Morphology evolution,Nanorods,Boron nitride,Catalyst
更新于2025-09-10 09:29:36
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Direct imaging of Indium-rich triangular nanoprisms self-organized formed at the edges of InGaN/GaN core-shell nanorods
摘要： Higher indium incorporation in self-organized triangular nanoprisms at the edges of InGaN/GaN core-shell nanorods is directly evidenced by spectral cathodoluminescence microscopy in a scanning transmission electron microscope. The nanoprisms are terminated by three 46 nm wide a-plane nanofacets with sharp interfaces forming a well-defined equilateral triangular base in the basal plane. Redshifted InGaN luminescence and brighter Z-contrast are resolved for these structures compared to the InGaN layers on the nanorod sidewalls, which is attributed to at least 4 % higher indium content. Detailed analysis of the inner optical and structural properties reveals luminescence contributions from 417 nm up to 500 nm peak wavelength proving the increasing indium concentration inside the nanoprism towards the nanorod surface.
关键词： cathodoluminescence microscopy,InGaN/GaN core-shell nanorods,nanoprisms,scanning transmission electron microscope,indium incorporation
更新于2025-09-10 09:29:36
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Photothermal Therapy Employing Gold Nanoparticle- Loaded Macrophages as Delivery Vehicles: Comparing the Efficiency of Nanoshells Versus Nanorods
摘要： Macrophages (Ma) loaded with gold-based nanoparticles, which convert near infrared light to heat, have been studied as targeted transport vectors for photothermal therapy (PTT) of tumors. The purpose of the experiments reported here was to compare the efficacy of gold-silica nanoshells (AuNS) and gold nanorods (AuNR) in macrophage-mediated PTT. Photothermal therapy efficacy was evaluated in hybrid glioma spheroids consisting of human glioma cells and either AuNS- or AuNR-loaded Ma, designated MaNS and MaNR, respectivly. Spheroids were irradiated for 10 minutes with light from an 810-nm diode laser at irradiances ranging from 0 to 28 W/cm2. Photothermal therapy efficacy was determined from spheroid growth over a 14-day period. The uptake by Ma of pegylated AuNR (3.9 ± 0.9 %) was twice that of pegylated AuNS (7.9 ± 0.7%). Hybrid spheroids consisting of a 5:1 ratio of glioma cells to loaded Ma exhibited significant growth inhibition with MaNS when subjected to irradiances of 7 W/cm2 or greater. In contrast, no significant growth inhibition was observed for the MaNR hybrid spheroids at this 5:1 ratio, even at the highest irradiance investigated (28 W/cm2). Although AuNR were taken up by Ma in larger numbers than AuNS, MaNS were shown to have greater PTT efficacy compared to MaNR for equivalent numbers of loaded Ma.
关键词： photothermal therapy,glioma,murine macrophages,gold-silica nanoshells,gold nanorods
更新于2025-09-09 09:28:46
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Thermal Reshaping Dynamics of Gold Nanorods: Influence of Size, Shape, and Local Environment
摘要： The thermal reshaping of gold nanorods in a polymer matrix is an important phenomenon for many potential applications. However, a fundamental understanding of the various mechanisms that govern the nanorod reshaping dynamics is still lacking. Here we provide evidence for a phenomenological model of the gold nanorod shape transformation based on the measurements and detailed analysis of the time-resolved thermal reshaping for a variety of gold nanorods having different geometries (aspect ratio, volume, diameter) in a crosslinked epoxy matrix at application relevant temperatures (120 ? 220 ?C). Our analysis suggests that a) the nanorod reshaping dynamics consist of two temporal regimes that are governed by different phenomena, and b) the ultimate amount of reshaping at a given temperature depends strongly on the initial particle geometry and the mechanical stiffness of its surroundings. At short times the shape transformation is dominated by a curvature-induced surface diffusion process in which the activation energy for diffusion depends on curvature. At long times, however, the surrounding environment plays a key role in slowing the diffusion and stabilizing the nanorod shape. We show that the long time behavior can be well described using a modified surface diffusion model that takes into account the slowing of atomic diffusivity as a result of external forces arising from mechanical constraints. The ability to tune both the final shape and the reshaping dynamics in nanocomposites opens up new possibilities in tailoring the optical properties of these materials.
关键词： Polymer Nanocomposites,Surface Diffusion,Temperature Sensing,Plasmonics,Thermal Reshaping,Gold Nanorods
更新于2025-09-09 09:28:46