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Synthesis of plasmonic Fe/Al nanoparticles in ionic liquids
摘要： Bottom-up and top-down approaches are described for the challenging synthesis of Fe/Al nanoparticles (NPs) in ionic liquids (ILs) under mild conditions. The crystalline phase and morphology of the metal nanoparticles synthesized in three different ionic liquids were identified by powder X-ray diffractometry (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected-area electron diffraction (SAED) and fast Fourier transform (FFT) of high-resolution TEM images. Characterization was completed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) for the analysis of the element composition of the whole sample consisting of the NPs and the amorphous background. The bottom-up approaches resulted in crystalline FeAl NPs on an amorphous background. The top-down approach revealed small NPs and could be identified as Fe4Al13 NPs which in the IL [OPy][NTf2] yield two absorption bands in the green-blue to green spectral region at 475 and 520 nm which give rise to a complementary red color, akin to appropriate Au NPs.
关键词： plasmonic properties,bottom-up synthesis,ionic liquids,Fe/Al nanoparticles,top-down synthesis
更新于2025-09-23 15:21:01
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Additive-controlled synthesis of monodisperse single crystalline gold nanoparticles: interplay of shape and surface plasmon resonance
摘要： We introduce a three-step seed-mediated synthesis for single crystalline gold nanoparticles (Au NPs) stabilized by hexadecylpyridinium chloride (CPC) in variable sizes with an adjustable ratio of the cubic and octahedral facets. The effect of KBr and ascorbic acid (AA) on shape and growth kinetics is systematically investigated. The kinetic data were evaluated using the minimalistic Finke-Watzky autocatalytic two-step mechanism, which allows to estimate the rate constants of the “pseudoelementary” reactions. The proposed surface-mediated mechanism of reduction of gold ions and Au NPs growth allows to explain the effect of gradual increase of bromide ion concentration on switching the Au NPs morphology from cubic to octahedral. The plasmonic properties of single particles of different facetings and their assemblies are investigated.
关键词： gold nanoparticles,Finke-Watzky mechanism,plasmonic properties,seed-mediated synthesis,surface plasmon resonance
更新于2025-09-23 15:21:01
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Molecular-Level Control over Plasmonic Properties in Silver Nanoparticle/Self-Assembling Peptide Hybrids
摘要： The plasmonic properties of silver nanoparticle (AgNP) arrays are directly controlled by AgNP size, shape, and spatial arrangement. Reported here is a strategy to prepare chiral AgNP arrays templated by two constitutionally isomeric aromatic peptide amphiphiles (APAs), KS C′EKS and C′EKSKS (KS = S-aroylthiooxime-modi?ed lysine, C′ = citrulline, and E = glutamic acid). In phosphate bu?er, both APAs initially self-assembled into nanoribbons with a similar geometry. However, in the presence of silver ions and poly(sodium 4-styrenesulfonate) (PSSS), one of the nanoribbons (KS C′EKS) turned into nanohelices with a regular twisting pitch, while the other (C′EKSKS) remained as nanoribbons. Both were used as templates for synthesis of arrays of ～8 nm AgNPs to understand how small changes in molecular structure a?ect the plasmonic properties of these chiral AgNP/APA hybrids. Both hybrids showed improved colloidal stability compared to pure AgNPs, and both showed enhanced sensitivity as surface-enhanced Raman spectroscopy (SERS) substrates for model analytes, with nanohelices showing better SERS performance compared to their nanoribbon counterparts and pure AgNPs.
关键词： self-assembling peptide,silver nanoparticle,plasmonic properties,chiral AgNP arrays,SERS
更新于2025-09-23 15:21:01
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Electronic and plasmonic phenomena at nonstoichiometric grain boundaries in metallic SrNbO <sub/>3</sub>
摘要： Grain boundaries could exhibit exceptional electronic structure and exotic properties, which are determined by a local atomic configuration and stoichiometry that differs from the bulk. However, optical and plasmonic properties at the grain boundaries in metallic oxides have rarely been discussed before. Here, we show that non-stoichiometric grain boundaries in the newly discovered metallic SrNbO3 photocatalyst show exotic electronic, optical and plasmonic phenomena in comparison to bulk. Aberration-corrected scanning transmission electron microscopy and first-principles calculations reveal that a Nb-rich grain boundary exhibits an increased carrier concentration with quasi-1D metallic conductivity, and newly induced electronic states contributing to the broad energy range of optical absorption. More importantly, dielectric function calculations reveal extended and enhanced plasmonic excitations compared with bulk SrNbO3. Our results show that non-stoichiometric grain boundaries might be utilized to control the electronic and plasmonic properties in oxide photocatalysis.
关键词： plasmonic properties,SrNbO3,grain boundaries,photocatalysis,metallic oxides
更新于2025-09-23 15:19:57
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Plasmonic Metamaterial Gels with Spatially Patterned Orientational Order via 3D Printing
摘要： Optical properties can be programmed on mesoscopic scales by patterning host materials while ordering their nanoparticle inclusions. While liquid crystals are often used to define the ordering of nanoparticles dispersed within them, this approach is typically limited to liquid crystals confined in classic geometries. In this work, the orientational order that liquid crystalline colloidal hosts impose on anisotropic nanoparticle inclusions is combined with an additive manufacturing method that enables engineered, macroscopic three-dimensional (3D) patterns of co-aligned gold nanorods and cellulose nanocrystals. These gels exhibit polarization-dependent plasmonic properties that emerge from the unique interaction between the host medium’s anisotropic optical properties defined by orientationally ordered cellulose nanocrystals, from the liquid crystal’s gold nanorod inclusions, and from the complexity of spatial patterns accessed with 3D printing. The gels’ optical properties that are defined by the interplay of these effects are tuned by controlling the gels’ order, which is tuned by adjusting the gels’ cellulose nanocrystal concentrations. Lithe optical responsiveness of these composite gels to polarized radiation may enable unique technological applications like polarization-sensitive optical elements.
关键词： liquid crystals,optical properties,nanoparticles,plasmonic properties,cellulose nanocrystals,gold nanorods,3D printing
更新于2025-09-12 10:27:22
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The IR plasmonic properties of sub-wavelength ITO rod arrays predicted by anisotropic effective medium theory
摘要： Simple three-layer Fresnel equations combined with Maxwell-Garnett approximation were applied to study the IR plasmonic properties of ITO nanorods. By treating the anisotropic nanorod layer as a layer with an effective dielectric constant, and using anisotropic effective medium theory, we were able to accurately predict the surface plasmon resonance behavior of ITO nanorods with different nanorod length, spacing, and tilt angle. This model allows a fast and computationally inexpensive calculation to predict the plasmonic properties of arrayed nanorods.
关键词： IR plasmonic properties,ITO nanorods,anisotropic effective medium theory
更新于2025-09-12 10:27:22
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Dumbbell–Like Silica Coated Gold Nanorods and their Plasmonic Properties
摘要： Silica coated gold nanorods with dumbbell-like morphology allowing dual functionalization in an individual nanostructure have attracted great attention for applications such as sensing and biological imaging. We report a detailed study on the feasibility of controlling the morphology of silica coating on gold nanorods. The morphology of the silica shell can be either cylindrical or dumbbell shaped. The morphology of the silica shell can be either cylindrical or dumbbell shaped. With constant GNR concentration, the ratio of CTAB and TEOS concentration is the key to determine the amount of available TEOS for silica deposition on GNR since the TEOS will diffuse towards the surface of GNRs. The effect of morphologies on surface-enhanced Raman scattering (SERS) performance was also investigated and we found that the dumbbell morphology of silica coated gold nanorods has the most significant SERS enhancement. Our study is significant in terms of the capability to control the dumbbell morphology of silica coated gold nanorods, which can eventually broaden the application of these plasmonic nanomaterials.
关键词： SERS,TEOS,plasmonic properties,dumbbell-like morphology,CTAB,Silica coated gold nanorods
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Simulation of the Plasmonic Properties of Gold Nanosponges with Nanotomographically Reconstructioned Models
摘要： The plasmonic properties of gold nanosponges with nanotomographically reconstructed models are very interesting due to their high internal surface area and the possibility to build a model with the exact same structure as the real sample. In order to better understand the structure-property relationship, the optical properties of gold nanosponges were simulated with the exact same structure as the real sample. The results confirm that the nanosponges have a strong plasmonic effect, which is very similar to the plasmonic effect of gold nanoparticles. The specific internal surface area was computed from the 3D data and compared with the specific internal surface area of the real sample. The results show that the nanosponges have a specific internal surface area of about 20 m2/g, which matches well with the specific internal surface area of the real sample. The nanosponges also show a strong plasmonic effect in the near-infrared region, which is very interesting for applications in photothermal therapy and biosensing.
关键词： optical properties,biosensing,nanotomography,gold nanosponges,plasmonic properties,photothermal therapy
更新于2025-09-11 14:15:04
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Controllable “Clicked-to-Assembled” Plasmonic Core–Satellite Nanostructures and Its Surface-Enhanced Fluorescence in Living Cells
摘要： The assembly of noble-metal core?satellite (CS) nanostructures is an appealing means to control their plasmonic properties for applications such as surface-enhanced ?uorescence or Raman scattering. However, till now there is a lack of some rapid or convenient methods to construct stable CS nanostructures. Here, we proposed a “clicked-to-assembly” strategy based on the fast and speci?c “click chemistry” reaction between trans-cyclooctene (TCO) and 1,2,4,5-tetrazine (Tz). The CS nanostructures were constructed within 8 min by simple mixing of TCO- or Tz-modi?ed nanoparticles (TCO-NPs or Tz-NPs) without any catalysts or heating required. Transmission electron microscopy experiments show that the constructed CS nanostructures are uniform, and particularly the number of “satellite” nanoparticles in the core surface is controllable by simply adjusting the feeding ratio of TCO-NPs or Tz-NPs in the reaction. The strong surface plasmon coupling e?ect (SPCE) was observed in these CS nanostructures, which was dependent on the coverage degree, size and composition of the satellite, and core NPs. The nanostructures with tuned surface plasmon resonance (SPR) e?ect were tried for the surface-enhanced ?uorescence in living cells. Such well-de?ned CS nanostructures could potentially serve as e?cient SPR-enhanced ?uorescent probes as diagnostics or biomedical imaging agents in nanomedicine.
关键词： core?satellite nanostructures,surface-enhanced ?uorescence,plasmonic properties,nanomedicine,click chemistry
更新于2025-09-11 14:15:04
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Magneto-Plasmonic Co@Pt@Au Nanocrystals for Biosensing and Therapeutics
摘要： Multifunctional nanoparticles (NPs) exhibiting high magnetic property and plasmonic resonance, are expected to be advanced nanomaterials which enable therapy, detection and diagnosis simultaneously for medical applications. To achieve the practical performance of the multifunctional NPs, the precise design and synthesis both are required. In this work, considering the chemical stability and controllability, Co-Pt@Au core-shell NPs, which exhibit high magnetic property and plasmonic resonance were theoretically designed based on calculation and then experimentally synthesized using alcohol reduction method. Co-Pt NPs were uniformly synthesized using a technique which enables reduction control of Pt through the formation of Pt-oleylamine complex. Moreover, depending on Co/Pt ratio, distribution of Co and Pt in a nanoparticle were precisely controlled, and as a result, Co-Pt alloy and Co@Pt core-shell NPs were individually prepared. In particular, Co@Pt NPs exhibit a high magnetic property and are suitable for Au coating due to a small lattice mismatch. In fact, Au coating onto Co@Pt NPs was successfully performed via inhomogeneous nucleation, which results in Co@Pt@Au NPs exhibiting plasmonic response of Au with high magnetic property and being dispersed in water by ligand-exchange for in-vivo use. The developed synthetic method enables designed synthesis of complicated multicomponent nanoparticles through tunable reduction reaction and provides highly potential NPs for transport and sensing applications.
关键词： Biomedical nanomaterials,Pt-Oleylamine complex,Magnetic and plasmonic properties,Magnetic transport,Alcohol reduction method,Sensing,Co@Pt@Au colloidal nanoparticles,Ligand exchange
更新于2025-09-11 14:15:04