Controllable Optical Activities and Rotatable Polarization Selectivity of Chiral GNH@TiO ₂ Nanostructures

ABSTRACT Hybrid chiral nanostructures hold great promise for next‐generation photonic, catalytic, and biomedical technologies. However, the construction of hybrid chiral nanoparticles (NPs) with tunable chiroptical activity, high anisotropy factor (g‐factor), and broad application potential remains a considerable challenge. Here, we report a chiral plasmon‐dielectric coupling strategy to construct helicoid Au core‐TiO 2 shell nanostructures (GNH@TiO 2 ) with enhanced and tunable chiroptical activity. By precisely controlling the TiO 2 shell thickness, the optical activity profiles of the hybrid nanostructures are effectively extended to the near‐infrared region with an enhanced g‐factor up to 0.14. Systematic analysis indicates that the shell‐dependent g‐factors of GNH@TiO 2 hybrids are closely associated with the chiral configuration of the hybrid structure induced by the coating of TiO 2 , as well as the electron transfer dynamics between GNH and TiO 2 . Moreover, the chiral GNH@TiO 2 with a high g‐factor exhibits asymmetric color modulation capability. Our findings provide a successful platform for engineering chiral hybrid nanostructures with tunable optical activities and mechanistic insights into the chiral plasmon‐semiconductor interactions.