Many researches about plasmonic materials with chirality has been carried out due to their intensive light-manipulating ability. However, synthesis of plasmonic nanoparticles have difficulties in delicate structure-making. In an effort to solve the problems, we focus on nature materials which have delicate chiral nanostructure and their ability to transfer properties from starting organic material to inorganic material, and vice versa. Previously, we presented a novel fabrication method for gold helicoid nanoparticles by peptide-assisted method<sup> </sup>which transfer intrinsic chirality of organic material (peptide) to inorganic achiral gold nanoparticle to manage their morphology and chirality. The synthesized gold helicoid nanoparticles had fine chiral nanostructure in nanoscale level. Based on this structure, they exhibit strong optical activity with Kuhn’s dissymmetry factor 0.2 in visible range under CPL(circularly polarized light). This intense optical activity also can be seen in polarization-sensitive color modulation in far-field transmission of randomly dispersed solution. In an extension of our newly developed synthesis strategy, now, we are doing research about coupling behavior from periodically arrayed Helicoid gold nanoparticles to see enhanced optical properties and apply our nanoparticles to appropriate field. Generally, periodically assembled plasmonic nanoparticles show coupled resonance which induce another spectral peaks resulting in Fano-like resonance. Inspired from this, we assembled chiral Helicoid nanoparticles in periodic way utilizing soft templates. Assembled chiral nanoparticles showed collective resonance behavior and strong enhancement in CD signal. Interestingly, resonance position of assembled chiral nanoparticles is tunable upon incidence angle of light and periodicity of array. Also, quality of chiral lattice resonance increased as we increase incidence angle of light. Based on this enhanced chiroptical properties from assembled chiral nanoparticles, we expect this strategy and template can be new break-through to colloidal chiral nanoparticles for being applied in various field such as, chiral sensing, wave plate, etc.

Chiral lattice plasmon generation from 3 dimensionally chiral helicoid gold nanoparticles

ACS Fall 2020 Virtual Meeting

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