Using the angular emission of light to understand electronic dipole tunability in perovskite nanocrystals and fused structures

The observation of extraordinary quantum optical phenomena, which has been historically limited to exotic materials, is now being observed in colloidally synthesized perovskite nanomaterials. Because quantum phenomena often exhibit highly directional properties, we must understand their fundamental directional light-material properties. In this presentation, we will focus on the angular light emission properties of CsPbX₃ (X – halide) nanocrystals. We use back focal plane microscopy to determine the electronic transition alignments and quantify how structure and local environments drive these behaviors. Here I show that smaller nanoparticles have more in-plane light emission while larger, fused nanoparticles have more out-of-plane light emission. Despite their level of confinement being the same, these results show that smaller particles are more responsive to nearest-neighbor interactions – something which is unique to this class of materials. Understanding the interplay of surface chemistry and structure of these nanomaterial assemblies will elucidate why these nanocrystals, which typically suffer from optical decoherence and inhomogeneity, can achieve these quantum-light characteristics and further allow us to rationally design materials for next generation technologies.