Origin of the Plasmonic Chirality of Gold Nanorod Trimers Templated by DNA Origami.

Templated by DNA origami, plasmonic gold nanorods (AuNRs) could be assembled into complex nanostructures with strong chiroptical activities. However, it is still not clear how the plasmonic chirality of a complex nanostructure matters with its daughter structural components. Here, we rationally design and fabricate a series of AuNR trimers and their daughter AuNR dimers. Strikingly, we corroborate by circular dichroism spectroscopy that the plasmonic chirality of asymmetrical AuNR trimers is a nearly perfect summation of the chiroptical response of all their constituent dimeric components. Our results provide fundamental insight into the origin of the plasmonic chirality of complex nanostructures.