Assembled plasmonic asymmetric heterodimers with tailorable chiroptical response.

Directed nanocrystal (NC) heteroassemblies could potentially achieve tailorable multiplex circular dichroism (CD) bands. Here, for the first time, we developed assembly of nanoparticle (NP)-nanorod (NR) chiral heterodimers with chiral molecules to explore their chiroptical activities. The experimental results revealed that plasmonic CD responses were in the region from 520 to 750 nm, which was in agreement with the theoretical simulation. Importantly, the CD band could be regulated by controlling the gaps between adjacent NCs and altering the building blocks of the assemblies. These results show that the plasmonic chiroptical response of NP-NR heterodimers could come from the finger-crossed chiral construction of adjacent NC in the heterodimers and the formation of plasmonic hot-spots in the assemblies could further enhance the plasmonic CD. This work provides a new opportunity to create heterogeneous nanoscale plasmonic objects with tailorable chiroptical response for application in biosensors, in vivo chiral medical carriers and negative refractive index materials.