Symmetry Breaking and Chiral Shaping of Au Nanodisks by Plasmon-Induced Ag Deposition under Circularly Polarized Light

Chiral plasmonic nanostructures attract attention recently, and one of the promising methods for chiral shaping is photoelectrochemical growth of the nanostructures under circularly polarized light (CPL).The CPL-induced method has been based on asymmetric and twisted electric field distribution generated around anisotropic plasmonic nanoparticles irradiated with CPL.In the present work, isotopic and symmetric Au nanodisks were used as plasmonic precursors, around which uniform electric fields were generated.When the Au nanodisks were irradiated with CPL in the presence of Ag ions and citrate ions, initial Ag deposition at an arbitrary site broke the symmetry, and gave rise to anisotropic and asymmetric electric field distribution, which leads to chiral shaping of Au-Ag nanostructures and chiroptical responses.