Coupling Silver Iodide Emitters to Aluminum Plasmons

Abstract

Silver iodide (AgI) is an efficient blue emitter that is easily synthesized and nanostructured. We investigate the coupling of AgI to plasmon modes, choosing aluminum (Al) owing to its low damping in the blue spectral range, in contrast to silver or gold. We investigate, first, an extended Al thin film overcoated with a SiO2 spacer layer and a AgI film. Spectroscopic surface plasmon resonance measurements confirm the anticrossing in the system's dispersion diagram, with a large energy splitting of about 140 meV, indicative of the onset of strong coupling. Second, we probe Al nanodisks overcoated with SiO2 and AgI, spectrally shifting the dipolar Al plasmon over the AgI absorption line by lithographically controlling the disk diameter. From extinction spectra, we again observe anticrossing, with an energy splitting of about 100 meV. Our results demonstrate that AgI is an easily fabricated and structured emitter, which in combination with Al forms an attractive platform to achieve an efficient plasmon-exciton coupling in the blue spectral range. © 2021 American Chemical Society.