Optical properties of symmetry-breaking tetrahedral nanoparticles

Zheng, Peng; Paria, Debadrita; Wang, Haitao; Li, Ming; Barman, Ishan

doi:10.1039/c9nr08515g

Cited by 15 publications

(21 citation statements)

References 53 publications

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“…Recent advancements in preparation of realistic quantities of catalytic nanoparticles with size-selection by gas phase deposition 10 , 11 have opened a way for us to study the shape-induced effects of nanocatalysts in a systematic way. Tetrahedral Pt nanoparticles would also exhibit unique plasmon responses 12 that can be explored in bio-sensing and spectroscopy of trace elements. The availability of size-tunable tetrahedral nanoparticles is therefore not only of fundamental interest, but of enormous practical values.…”

Section: Introductionmentioning

confidence: 99%

Shape control of size-selected naked platinum nanocrystals

et al. 2021

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Controlled growth of far-from-equilibrium-shaped nanoparticles with size selection is essential for the exploration of their unique physical and chemical properties. Shape control by wet-chemistry preparation methods produces surfactant-covered surfaces with limited understanding due to the complexity of the processes involved. Here, we report the controlled production and transformation of octahedra to tetrahedra of size-selected platinum nanocrystals with clean surfaces in an inert gas environment. Molecular dynamics simulations of the growth reveal the key symmetry-breaking atomic mechanism for this autocatalytic shape transformation, confirming the experimental conditions required. In-situ heating experiments demonstrate the relative stability of both octahedral and tetrahedral Pt nanocrystals at least up to 700 °C and that the extended surface diffusion at higher temperature transforms the nanocrystals into equilibrium shape.

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Section: Introductionmentioning

confidence: 99%

Shape control of size-selected naked platinum nanocrystals

et al. 2021

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“…The major plasmonic peak red-shifts from 564 to 594 nm with increasing tetrahedron size (Figure h). The gradual emergence of a small shoulder peak centered at ∼525 nm for larger tetrahedra likely results from the hybridization between quadrupole and dipole plasmonic vertex modes supported by gold tetrahedra …”

Section: Resultsmentioning

confidence: 99%

“…The gradual emergence of a small shoulder peak centered at ∼525 nm for larger tetrahedra likely results from the hybridization between quadrupole and dipole plasmonic vertex modes supported by gold tetrahedra. 38 To form 2D superstructures, a toluene solution of polymergrafted gold tetrahedra was allowed to dry on top of immiscible EG (Figure 2a). Narrowly dispersed PS-PEHA ligands with number-average molecular weights (M n ) ranging from 1.6 to 39 kDa were synthesized and grafted onto gold tetrahedra through ligand exchange (Figures S5 and S6 and Tables S2− S4).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Structural Diversity in Dimension-Controlled Assemblies of Tetrahedral Gold Nanocrystals

et al. 2022

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Polyhedron packings have fascinated humans for centuries and continue to inspire scientists of modern disciplines. Despite extensive computer simulations and a handful of experimental investigations, understanding of the phase behaviors of synthetic tetrahedra has remained fragmentary largely due to the lack of tetrahedral building blocks with tunable size and versatile surface chemistry. Here, we report the remarkable richness of and complexity in dimension-controlled assemblies of gold nanotetrahedra. By tailoring nanocrystal interactions from long-range repulsive to hard-particle-like or to systems with short-ranged directional attractions through control of surface ligands and assembly conditions, nearly a dozen of two-dimensional and three-dimensional superstructures including the cubic diamond and hexagonal diamond polymorphs are selectively assembled. We further demonstrate multiply twinned icosahedral supracrystals by drying aqueous gold nanotetrahedra on a hydrophobic substrate. This study expands the toolbox of the superstructure by design using tetrahedral building blocks and could spur future computational and experimental work on self-assembly and phase behavior of anisotropic colloidal particles with tunable interactions.

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“…Such a plasmonic substrate was selected because of the well-established fabrication protocol based on the nanosphere lithography and its well-understood optical properties for plasmonic biosensing that have been detailed in our previous studies. [39][40][41][42][43] The fabricated gold nanopyramid array featured a sharp pyramidal geometry arranged hexagonally onto the quartz substrate (Figure 2a). The sharp vertices and edges have been found to contribute to a significant local EM field enhancement for superior SERS applications.…”

Section: Resultsmentioning

confidence: 99%

A Dual‐Modal Single‐Antibody Plasmonic Spectro‐Immunoassay for Detection of Small Molecules

Zheng

Raj

et al. 2022

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Small molecules play a pivotal role in regulating physiological processes and serve as biomarkers to uncover pathological conditions and the effects of therapeutic treatments. However, it remains a significant challenge to detect small molecules given the size as compared to macromolecules. Recently, the newly emerging plasmonic immunoassays based on surface‐enhanced Raman scattering (SERS) offer great promise to deliver extraordinary sensitivity. Nevertheless, they are limited by the intrinsic SERS intensity fluctuations associated with the SERS uncertainty principle. The single transducer that relies on the intensity change is also prone to false signals. Additionally, the prevailing sandwich immunoassay format proves less effective towards detecting small molecules. To circumvent these critical issues, a dual‐modal single‐antibody approach that synergizes both the intensity and shift of the peak‐based immunoassay with Raman enhancement, coined as the INSPIRE assay, is developed for small molecules detection. With two independent transduction mechanisms, it allows better prediction of analyte concentration and attenuation of signal artifacts, providing a new and robust strategy for molecular analysis. With a proof‐of‐concept demonstration for detection of free T4 and testosterone in serum matrix, the authors envision that the INSPIRE assay could be expanded for a wide spectrum of applications in biomedical diagnosis, discovery of new biopharmaceuticals, food safety, and environmental monitoring.

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Optical properties of symmetry-breaking tetrahedral nanoparticles

Abstract: Tetrahedral nanoparticles are found to support counterintuitive extinction spectral splitting behavior owing to symmetry breaking and mediated by geometric roundness.

Cited by 15 publications

References 53 publications

Shape control of size-selected naked platinum nanocrystals

Shape control of size-selected naked platinum nanocrystals

Structural Diversity in Dimension-Controlled Assemblies of Tetrahedral Gold Nanocrystals

A Dual‐Modal Single‐Antibody Plasmonic Spectro‐Immunoassay for Detection of Small Molecules

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