Spectral Matching and Spatially Dependent Polarization-Selective Attenuation in Chiral Au-SiO2-Quantum Dot Nanohybrids.

Discrete colloidal nanohybrids that combine efficient achiral emitters with chiral plasmonic nanostructures offer a promising route to solution-processable circularly polarized luminescence (CPL)-active materials. Here, we construct Au/SiO2/QDs nanohybrids by assembling quantum dots (QDs) onto silica-coated chiral Au helicoids, where the SiO2 layer controls the separation between the QDs and the plasmonic core. When the QD emission is spectrally matched with the chiroptical response of the chiral Au/SiO2 nanoparticles, the Au/SiO2 ensemble acts as a nanopolarizer and produces strong CPL through polarization-selective attenuation. The resulting nanohybrids exhibit luminescence dissymmetry factor (glum) values reaching 0.12 in the visible region and 0.014 in the near-infrared region. To clarify how nanoscale arrangement influences CPL, we further construct spectrally mismatched nanohybrids in which the ensemble-level contribution is suppressed. In this regime, changing the SiO2 spacer thickness leads to a distance-dependent reversal of glum, indicating that QD emission experiences spatially dependent differential attenuation near the chiral Au surface. Optical simulations further reveal position-dependent differential attenuation across individual chiral Au helicoids, supporting the spatially heterogeneous origin of the CPL response in the mismatched system. These findings position chiral Au/SiO2/QDs nanohybrids as a useful colloidal platform for both strong CPL generation and spatially resolved control of polarization-selective attenuation.