Future combinations of plasmonics with nanometer-sized electronic circuits require strategies to control the electrical excitation of plasmons at the length scale of individual molecules. A unique tool to study the electrical plasmon excitation with ultimate resolution is scanning tunneling microscopy (STM). Inelastic tunnel processes generate plasmons in the tunnel gap that partially radiate into the far field where they are detectable as photons. Here we employ STM to study individual tris-(phenylpyridine)-iridium complexes on a C60 monolayer, and investigate the influence of their electronic structure on the plasmon excitation between the Ag(111) substrate and an Ag-covered Au tip. We demonstrate that the highest occupied molecular orbital serves as a spatially and energetically confined nanogate for plasmon excitation. This opens the way for using molecular tunnel junctions as electrically controlled plasmon sources.

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Even though medical devices have improved a lot over the past decades, there are still issues regarding their anti‐biofouling properties and tribological performance, and both aspects contribute to the short‐ and long‐term failure of these devices. Coating these devices with a biocompatible layer that reduces friction, wear, and biofouling at the same time would be a promising strategy to address these issues. Inspired by the adhesion mechanism employed by mussels, here, dopamine is made use of to immobilize lubricious mucin macromolecules onto both manufactured commercial materials and real medical devices. It is shown that purified mucins successfully adsorb onto a dopamine pre‐coated substrate, and that this double‐layer is stable toward mechanical challenges and storage in aqueous solutions. Moreover, the results indicate that the dopamine/mucin double‐layer decreases friction (especially in the boundary lubrication regime), reduces wear damage, and provides anti‐biofouling properties. The results obtained in this study show that such dopamine/mucin double‐layer coatings can be powerful candidates for improving the surface properties of medical devices such as catheters, stents, and blood vessel substitutes.