Uniform Chiral Gap Synthesis for High Dissymmetry Factor in Single Plasmonic Gold Nanoparticle

Abstract

Synthesis of chiral plasmonic materials has been highlighted for the last decades with their optical properties and versatile potential applications. Recently reported aqueous-based amino acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles with 432 point-group symmetry shows exceptionally high chiroptic response within 100 nm scales. Despite its already excellent chiroptic response, a single-nanoparticle dark field scattering study revealed that full chiroptic potential of chiral gold nanoparticle is limited with its overall synthetic uniformity. Based on this knowledge, we present a multi-chirality-evolution step synthesis method for the enhancement of chiroptic response through an increase in particle uniformity. Detailed time variant study and interrelationship study of reaction parameters allowed the systematic construction of design principles for chiral nanoparticles with exceptional chiroptic response. With the application of precisely controlled growth kinetic to two distinct growth regimes, modified chiral gold nanoparticles showed significantly improved uniformity, achieving an improved dissymmetry factor of g = 0.31. We expect that our strategy will aid in precise morphology and property control for chiral nanomaterials, which can be used in various plasmonic metamaterial applications.

Giant polarization anisotropic optical response from anodic aluminum oxide templates embedded with plasmonic metamaterials

“…It is important to note that at an incident angle of 70°, the differentiation between LCP and RCP is only focused on a narrow bandwidth at short wavelengths, resulting in a CD value that exceeds 0.5 from 400 nm to 435 nm with a maximum value of 0.7 attained at 430 nm. These CD signals are comparable to or even surpass the plasmonic optical activity in the visible range in recent studies [29,[49][50][51]. Figs.…”

A Single Chiral Nanoparticle Induced Valley Polarization Enhancement

“…However, uniformity of such chiral gold nanoparticles can be significantly increased by adopting multichirality‐evolution step synthesis method. [ 28 ]…”

Controlling the size and circular dichroism of chiral gold helicoids

“…The devised synthetic method demonstrated various nanoparticle morphologies and chiroptic responses, 14,15 which through systematic optimization of the synthetic conditions enhanced the g-factor up to 0.3. 16 However, control over the nanoparticle size and maximum chiroptic peak position was limited to a fixed size and wavelength. Therefore, we believe that synthetic efforts to precisely control the size and spectral position of 432 helicoid III could significantly broaden the range of applications to include size-sensitive or spectralsensitive nanoparticle applications such as cellular interaction studies or broadband optical communication systems.…”