DNA nanotechnology for light-emitting plasmonic applications

Abstract

DNA nanotechnology for light-emitting plasmonic applications - Sara Rocchetti. The development of plasmonic nanocavities allows for the direct observation of light-matter interactions at the nanoscale. Collective oscillations of electrons (SPPs) at a metal-dielectric interface confine light into nanometric spaces, sustaining an optical resonance. This resonance can be carefully tuned by changing the geometry and material of the gap. In this work, I use the NanoParticle-on-Mirror (NPoM) geometry to fabricate plasmonic cavities in a bottom-up fashion by simply drop casting gold nanoparticles on thin gold films. The existence of tightly confined optical modes enhances both electronic and vibrational transitions of the molecules present in the gap. To accurately position single molecules within these plasmonic cavities, I utilise DNA nanotechnology. This bottom-up, self-assembly technique facilitates the creation of molecular platforms at the nanoscale. By developing pro tocols to fabricate NPoM constructs where DNA nanostructures serve as molecular frameworks, I can precisely place single emitters within plasmonic gaps. This allows for the investigation of the emission properties of individual molecules and their interaction with metals at a sub-nanometric scale. By combining DNA nanotechnol ogy with NPoMs, I demonstrate that utilising various DNA constructs as scaffolds results in different regimes of light-matter interaction. This leads to the observation of amplified optical forces at the nanoscale and strongly coupled systems.