Nanometer control in plasmonic systems through discrete layer-by-layer macrocycle-cation deposition.

In this work, we demonstrate that coordination interactions between Fe3+ and cucurbit[7]uril (CB[7]) can be utilised to build up defined nanoscale spacing layers in metallic nanosystems. We begin by characterising the layer-by-layer deposition of CB[7] and FeCl3·6H2O coordination layers through the use of a Quartz-Crystal Microbalance (QCM) and contact angle measurements. We then apply this layered structure to accurately control the spacing, and thus optical properties, of gold nanoparticles in a Nanoparticle-on-Mirror (NPoM) structure, which is demonstrated via normalising plasmon resonance spectroscopy.European Commission for a Marie Curie Fellowship (NANOSPHERE, 658360) ERC starting investigator grant (ASPiRe 240629) RC acknowledges support from the Dr. Manmohan Singh scholarship from St. John’s College BdN acknowledges support from the Leverhulme Trust and the Isaac Newton trust ECF