Superfluorescence in Lead Halide Perovskite Nanocrystals

Abstract

Fully inorganic cesium lead halide perovskite nanocrystals have emerged as an interesting optoelectronic material due to several extraordinary properties. They exhibit giant oscillator strength and long dephasing time at cryogenic temperature as well as low inhomogeneous energetic broadening, which makes them ideally suited to explore settings that exploit their exceptionally strong intrinsic light-matter coupling and collective effects. Through drying-mediated self-assembly of the colloidal nanocrystals, we can realize various superlattice geometries where we observe coherent, cooperative emission. After optical excitation, the quantum dots spontaneously synchronize, thereby effectively emitting an intense burst of light with characteristic signatures of superfluorescence that will be discussed for different superlattice assemblies. Moreover, using thin films of giant perovskite nanocrystals, we investigate temperature- and density-driven transitions between superfluorescence and amplified spontaneous emission regimes.