Synthesis and Multipole Plasmon Resonances of Spherical Aluminum Nanoparticles

Abstract

In comparison to Au and Ag, the high plasma frequency of Al allows multipole plasmon resonances from the ultraviolet to visible (UV–vis) range to be achieved by its nanoparticles with much smaller sizes and even a spherical shape. Herein, we report the high-supersaturation growth of monodisperse spherical Al nanoparticles (Al NPs) from 84 to 200 nm and their distinctive size-dependent multipole plasmon resonance properties in the UV–vis range. Linear relationships between the particle diameter and resonance peak positions of the dipole, quadrupole, and octupole were observed experimentally and confirmed by finite-difference time-domain (FDTD) calculations. FDTD calculations further reveal the high scattering-to-extinction ratio of multipole modes for the particle diameters >100 nm. The extinction coefficients of spherical Al NPs with different diameters were also determined. The excellent matching between the experimental and simulated results in the present work not only offers a standard for the synthesis and characterization of high-quality Al NPs but also provides new insight into the multipole plasmonic properties of Al NPs for advanced optical and sensing applications.

Synthesis of Liquid Gallium@Reduced Graphene Oxide Core–Shell Nanoparticles with Enhanced Photoacoustic and Photothermal Performance

“…It is attributed to the sizedependent multipole plasmon resonance of GaNPs. 63 This result is quite similar to that of the previous studies of other LMbased colloidal solutions. 11,12,64 Due to the electron−electron and electron−phonon scattering, heat is transferred to the surroundings of the metallic nanostructure.…”

“…Plasmon resonance peaks of GaNPs deposited on the substrates in the UV range have been demonstrated experimentally and theoretically; − the UV–vis–NIR spectra shown in Figure S15 of colloidal GaNP solutions, however, did not show obvious plasmonic peaks. It is attributed to the size-dependent multipole plasmon resonance of GaNPs . This result is quite similar to that of the previous studies of other LM-based colloidal solutions. ,, Due to the electron–electron and electron–phonon scattering, heat is transferred to the surroundings of the metallic nanostructure. , The heat generated from localized surface plasmon resonance of LM-based particles over the near-infrared region has already been used in cancer therapy and nanomotors .…”

Spallation of Isolated Aluminum Nanoparticles by Rapid Photothermal Heating

“…The electric-field distribution and transient thermal response were simulated numerically using finite-element software ( COMSOL Multiphysics 5.2a ). The numerical simulations have been used in numerous recent reports − and were preferable to the analytical solution in solving partial differential equations (PDEs) for heterostructured models. The baseline spectral absorption of an Al NP surrounded by air was first evaluated and represented by the absorption cross section based on the Mie theory (Figure ).…”

Surface Plasmon Enhanced Fluorescence Temperature Mapping of Aluminum Nanoparticle Heated by Laser

“…The interband transitions of bulk aluminum have an intrinsic peak at 810 nm and the peak intensity grows with increasing particle diameters [75]. Below 600 nm, Al NPs can exhibit dipole, quadrupole, and octupole plasmonic resonances, of which peak wavelengths are red-shifted as the diameter increases [76]. The better confinement of light at these lower wavelengths leads to higher absorption such that the 808 nm wavelength exhibits a relatively weak plasmonic coupling compared to other laser wavelengths.…”