Plasmonic Chiral Photoheating using DNA-Nanocrystal Assemblies

Over the past decade, the field of chiral plasmonics has emerged as a novel way of manipulating the optical properties of metallic nanocrystals (NCs). Specifically, it was found that plasmonic NCs generate heat efficiently in the presence of electromagnetic radiation and even strongly when this is at the frequency of the plasmon resonance, hence allowing a great deal of tunability. Here, we use a chiral DNA-assembled nanorod pair as a model system for chiral plasmonic photo-heating, and we study the subsequent chiral photo-melting of its components. We show that both the enantiomeric excess and consequent circular dichroism can be controlled with chiral light, for both the single-complex and the collective heating regimes. The chiral asymmetry factors of the calculated photothermal and photo-melting effects exceed the values typical for the chiral molecular photochemistry at least 10-fold. Our proposed mechanism can be used to develop chiral photo-responsive systems controllable with circularly polarized light, e.g. for uses in photo-medicine or photocatalysis.