Remote Giant Multispectral Plasmonic Shifts of Labile Hinged Nanorod Array via Magnetic Field

Abstract

We report a remotely mediated and fast responsive plasmonic-magnetic nanorod array with extremely large variability in optical appearance (up to 100 nm shifts in scattering maxima) and concurrently for multiple wavelengths in a broad range from UV-vis to near-infrared (at 450, 550, and 670 nm) with an external magnetic field with variable direction. The observed phenomenon demonstrates a rapid, wide-range response controlled via a noninvasive remote stimulus. The remotely controlled system suggested here is a magnetic field-directed assembly of an ordered monolayer array of unipolar oriented magnetic-plasmonic nickel-gold nanorods flexibly hinged to a sticky substrate. The unique geometry of the mobile nanorod array allows for the instant alteration of the surface plasmon polariton modes in the gold segment of the controllably tilting nanorods. This design demonstrates the utility of hybrid bimetallic nanoparticles and gives a novel approach to the design of fast-acting, remotely controlled color-changing nanomaterials for sensing and interfacial transport.

Novel Ba-hexaferrite structural variations stabilized on the nanoscale as building blocks for epitaxial bi-magnetic hard/soft sandwiched maghemite/hexaferrite/maghemite nanoplatelets with out-of-plane easy axis and enhanced magnetization

“…[9][10][11] Moreover, the effective coupling of the nanoparticle magnetic moments with a magnetic field can be used in sensors. [12][13][14][15] In particular, magnetic nanoplatelets that display a high uniaxial magnetocrystalline anisotropy with an easy axis perpendicular to the platelet can be especially appropriate for certain applications. Barium hexaferrite (BaFe12O19, BHF) nanoplatelets are a classic example of this type of magnetic structure.…”

Self‐(Un)rolling Biopolymer Microstructures: Rings, Tubules, and Helical Tubules from the Same Material

“…Various responsive soft materials and structures have been utilized as dynamic components for selective drug encapsulation and targeting,11 energy harvesting and storage,12 and actuating micro‐robotic structures 13. Such actuating and adaptive structures have been based on a wide range of responsive materials, mostly involving elastomeric synthetic gels, which are responsive to pH, temperature, light, humidity, ionic strength, and magnetic and electric fields 14–16. However, for a variety of self‐rolling and self‐folding structures, careful tuning of composition, morphology, patterning schemes, and thicknesses of 2D templates is required.…”

Stimuli‐Responsive Optical Nanomaterials

“…This strategy was later extended to modulate the scattering of Au microplates by attaching small γ-Fe 2 O 3 nanoparticles [153] Block nanocomposites with integrated plasmonic and magnetic segments represent another type of magnetically responsive plasmonics, as demonstrated by block Ni-Au nanorods synthesized by electrochemical deposition in porous alumina templates. [154] By controlling their orientations magnetically, the strongest scattering peak shifted by more than 100 nm. During magnetic manipulation, however, irreversible aggregation of nanorods occurred due to the strong magnetic interaction and poor surface modification, which degrades the optical performance.…”