Controlling the size and circular dichroism of chiral gold helicoids†
The precise control of size and optical response holds significance in various applications, but the detailed control of the contributing electric dipole and magnetic dipole to tune the chiroptic response remains a challenge. In this work, we systematically controlled the size- and optical-properties of chiral gold 432 helicoid III nanoparticles using an aqueous-based seed-mediated method. Control of the Au metal precursor and glutathione concentration yields various sizes of chiral nanoparticles with a precisely controlled geometry from 100 nm to 180 nm and maximum chiroptic peak positions from 540 nm to 650 nm. Based on this synthetic platform, a comprehensive understanding of chiral morphology, optical response, and the corresponding simulation data has been developed.