Research in the Lange group: Polaritons in binary nanoparticle superlattices - gold crystals catch light

29 June 2022

Photo: Florian Schulz

Boundary between monolayer (right) and bilayer of gold nanoparticle films. The superimposition of the two layers creates a moiré effect.

In a seminal work published in Nature (Vol. 583, pp. 780, 2020), a team of researchers led by Stephanie Reich (FU Berlin), Florian Schulz and Holger Lange (Universität Hamburg) demonstrated extremely strong light-matter interaction with periodically ordered metal nanoparticles. Whether light is guided through these so-called supercrystals, focused into the gaps between the nanoparticles or absorbed in them depends on the supercrystal geometry.

The goal of the recently approved Research Grant is to explore the resulting possibilities to construct optical designer materials.
For example, the combination of nanoparticles of different sizes (binary supercrystals) can resemble the rock salt lattice structure. There, light is supposed to be focused into the gaps and might interact strongly with fluorescent dyes or photocatalysts, enhancing light emission or photocatalytic activity. The German Research Foundation funds the joint project of FU Berlin and Universität Hamburg with 500,000 EUR.