Spatial Confinement of Electromagnetic Hot and Cold Spots in Gold Nanocubes

Abstract

We report a near-field imaging study of colloidal gold nanocubes. This is accomplished through a photochemical imaging method in which molecular displacements are vectorial in nature, enabling sensitivity to the polarization of the optical near-field of the nanocubes. We analyze the confinement of both electromagnetic hot and "cold" spots with a resolution of λ/35 and emphasize the particularly high spatial confinement of cold spots. The concept of a cold spot complements the well-known electromagnetic hot spot but can have significant advantages. The application of the ultraconfined cold spots to high resolution imaging and spectroscopy is discussed.

A review on plasmonic metal⿿TiO2 composite for generation, trapping, storing and dynamic vectorial transfer of photogenerated electrons across the Schottky junction in a photocatalytic system

“…These photoexcited electrons directly get injected into the nearby TiO 2 CB due to the formation of Schottky barrier at the metal semiconductor interface. It was also suggested that the hot spots (plasmon decay producing intensely hot electrons) appear on the sharp edges and corners of TiO 2 where the electric field intensity of SPR is several times higher than that of the incident electric field of the photon [201][202][203][204]. Electron hole pairs are generated by surface plasmon decay and the rate of generation is intensified by the local filed enhancement on the hot spot regions (Fig.…”

Azopolymer‐based micro‐ and nanopatterning for photonic applications

“…More recently, azopolymers have been employed to map the optical near fields around various types of metal nanostructures . Typically, a thin azopolymer layer is spin coated onto a plasmonic array, and the topographic modification upon irradiation is observed to closely follow the near‐field intensity distribution around the structures .…”

Recent advancements in plasmon-enhanced promising third-generation solar cells

“…The IPCE enhancement ratio graph clearly shows photocurrent enhancement in the 550-800-nm region of the spectrum, corresponding to the LSPR of the popcorn-shaped metal NPs (Figure 18). Au@SiO 2 nanocubes were found advantageous over spherical NPs in DSCs, as they had two times higher extinction and absorption efficiency, two times larger surface area, and higher electromagnetic field localization at edges and corners [49,30,98,99]. The edge length of Au nanocubes can be adjusted by hexadecyltrimethylammonium bromide (CTAB) ligands [100].…”