Fig. 4: Morphology and chirality evolution of the chiral nanocrystals grown from the Au nanodisks by HADG.

The Au nanodisks with a size of 90/30 nm and the diameter-to-thickness ratio of 3.0 were employed as the seeds. a Effect of the KI concentration on the morphology of the obtained chiral nanocrystals. The 432 helicoid III nanocrystals are formed at low I⁻ concentrations (0.5–1.0 μM) and the 432 helicoid IV nanocrystals start to appear as the I⁻ concentration is increased. Further addition of KI (1.8–8.0 μM) finally results in the generation of the Au nanotriskelions. The morphology evolution was confirmed by SEM imaging. The scale bars in all the SEM images are the same. b Spectral evolution of the extinction g-factors for the chiral nanocrystals in (a). The chirality inversion of the optical response demonstrates that the grown chiral nanocrystals change from the 432 helicoid III nanocrystals to the Au nanotriskelions. The dashed lines show the spectral evolution with increasing KI concentrations. c Dependence of the extinction g-factors of the grown chiral nanocrystals on the concentrations of CTAB and KI. The dashed frames show the grown chiral nanocrystals with FFR symmetry. Source data are provided as a Source Data file.