Dipole-like electrostatic asymmetry of gold nanorods

Kim, Ji-Young; Han, Myung Geun; Lien, Miao-Bin; Magonov, Sergei; Zhu, Yimei; George, H.; Norris, Theodore B.; Kotov, Nicholas A.

doi:10.1126/sciadv.1700682

Cited by 47 publications

(40 citation statements)

References 56 publications

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“…An additional contribution to the significant chirality amplification observed here experimentally could be the dipole-like electrostatic asymmetry of the gold nanorods themselves. Using a range of electron microscopy techniques, Kelvin probe microscopy, and simulations Kotov and co-workers showed that gold nanorods capped with CTAB surfactant bilayers (the starting point for the GNR synthesis and surface modification described herein) are non-centrosymmetric resulting from an uneven distribution of CTAB molecules on the nanorod surface 38 .…”

Section: Resultsmentioning

confidence: 99%

Chirality amplification by desymmetrization of chiral ligand-capped nanoparticles to nanorods quantified in soft condensed matter

et al. 2018

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Induction, transmission, and manipulation of chirality in molecular systems are well known, widely applied concepts. However, our understanding of how chirality of nanoscale entities can be controlled, measured, and transmitted to the environment is considerably lacking behind. Future discoveries of dynamic assemblies engineered from chiral nanomaterials, with a specific focus on shape and size effects, require exact methods to assess transmission and amplification of nanoscale chirality through space. Here we present a remarkably powerful chirality amplification approach by desymmetrization of plasmonic nanoparticles to nanorods. When bound to gold nanorods, a one order of magnitude lower number of chiral molecules induces a tighter helical distortion in the surrounding liquid crystal–a remarkable amplification of chirality through space. The change in helical distortion is consistent with a quantification of the change in overall chirality of the chiral ligand decorated nanomaterials differing in shape and size as calculated from a suitable pseudoscalar chirality indicator.

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Section: Resultsmentioning

confidence: 99%

Chirality amplification by desymmetrization of chiral ligand-capped nanoparticles to nanorods quantified in soft condensed matter

et al. 2018

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“…4h. The organic stabilizers used in the synthesis of the nanoparticles may persist on the surface and contribute to charging [21]. There are clusters on the surface of the particles which may be electrically insulated.…”

Section: Methodsmentioning

confidence: 99%

“…Off-axis electron holography offers a more interpretable measurement of phase with respect to a vacuum reference wave. This allows, for example, imaging of magnetic bits in recording media [20] and insight into the charge distribution and asymmetry of nanoparticles [21]. However, as interference fringes are in real space, resolution is limited by the spacing of fringes [22], coherence, and biprism stability.…”

Section: T(x)mentioning

confidence: 99%

Interpretable and Efficient Interferometric Contrast in Scanning Transmission Electron Microscopy with a Diffraction-Grating Beam Splitter

et al. 2018

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Efficient imaging of biomolecules, 2D materials and electromagnetic fields depends on retrieval of the phase of transmitted electrons. We demonstrate a method to measure phase in a scanning transmission electron microscope using a nanofabricated diffraction grating to produce multiple probe beams. The measured phase is more interpretable than phase-contrast scanning transmission electron microscopy techniques without an off-axis reference wave, and the resolution could surpass that of off-axis electron holography. We apply the technique to image nanoparticles, carbon substrates and electric fields. The contrast observed in experiments agrees well with contrast predicted in simulations.

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“…In addition, the asymmetry of individual nanorods can augment the structural chirality of assemblies mad from them. For instance, the recently discovered asymmetry of Au NRs is likely to pay a role in generating plasmonic CD . In future, advanced characterization methods are needed for deeper nature.…”

Section: Summary and Perspectivementioning

confidence: 99%

Plasmonic Circular Dichroism of Gold Nanoparticle Based Nanostructures

Meng

Lin

et al. 2019

Advanced Optical Materials

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IntroductionChirality refers to the certain handedness in geometry with a mirror image that cannot coincide with itself. [1] Mirror images with opposite chirality are enantiomers, and can be divided into left-and right-handedness, respectively. Two enantiomers can interact differently with left-(LCP) and right-circularly With great advances in wet chemical synthesis of nanoparticles (NPs), plasmonic NPs with various sizes and morphologies are easily available nowadays and demonstrate great potentials in optical, electronic, and biomedical applications. Plasmonic circular dichroism (CD), relating to circular dichroism responses at localized surface plasmon resonance of metal nanostructures, has emerged as a research direction of plasmonics with promising prospects in enantioselective catalysis, chiral separation, and ultrasensitive detections. Herein, plasmonic CD responses of gold nanoparticle based nanostructures are summarized. Two kinds of plasmonic CD phenomena are investigated: structural CD and induced CD. Structural CD is the response from chiral assemblies composed of plasmonic NPs with strong dipole-dipole interactions. Induced CD is the response of nonchiral plasmonic NPs with chiral molecules attached at surface. The weak CD is the result of Coulomb interaction between chiral molecules and plasmonic NPs. Efforts on how to achieve strong CD signals for these two configurations by using chiral molecules and Au nanoparticles are reported. The fabrication of chiral nanostructures, tuning and amplification of CD responses, CD-based biosensors, chiral catalysis, and future perspectives are presented. The importance of the shape anisotropy of gold nanorods in the generation and amplification of CD signals is especially highlighted.

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Dipole-like electrostatic asymmetry of gold nanorods

Abstract: Seemingly symmetric nanoscale cylinders have hidden asymmetry of charge distribution.

Cited by 47 publications

References 56 publications

Chirality amplification by desymmetrization of chiral ligand-capped nanoparticles to nanorods quantified in soft condensed matter

Chirality amplification by desymmetrization of chiral ligand-capped nanoparticles to nanorods quantified in soft condensed matter

Interpretable and Efficient Interferometric Contrast in Scanning Transmission Electron Microscopy with a Diffraction-Grating Beam Splitter

Plasmonic Circular Dichroism of Gold Nanoparticle Based Nanostructures

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