Synthesis and Plasmonic Chiroptical Properties of Double‐Helical Gold Nanorod Enantiomers

Abstract Chiroplasmonic nanostructures have drawn increasing attention in the applications of photonics, biosensing, and asymmetric catalysis owing to their intense chiroptical activities. However, the types of plasmonic nanoparticles with the intrinsic chiral shapes are still rare now. Herein, the authors report a seed‐mediated strategy for synthesis of chiral‐morphology gold nanorods (GNRs) with a novel 222 symmetry as same as that of DNA double helixes. The chiral GNRs with their sides twisted into a double‐helical‐strip shape are synthesized by the formation of high‐Miller‐index side surfaces through the regrowth of GNRs. The chiral GNRs exhibit an excellent plasmonic circular dichroism response in the visible and near‐infrared regions, which is consistent with the finite‐difference time‐domain simulations. Moreover, by adjusting synthetic parameters, the shape and chiroptical response of 222‐symmetry chiral GNRs can be tuned. This work holds a promise for the fabrication of chiroplasmonic nanoparticles with tailored shapes toward chiroptical applications.