Determine the carrier-population scaling governing superfluorescence in quasi-2D lead-halide perovskites

Determine whether excitons constitute the majority carrier population in two-dimensional and quasi-two-dimensional lead-halide perovskites or are only transiently formed from a plasma of unbound electrons and holes, and consequently establish the relationship between excitation fluence and the number of superfluorescent emitters.

Background

The supplementary analysis discusses how the number of emitters participating in superfluorescence should scale with excitation fluence. Ideal Dicke-model relations depend on this scaling, but the appropriate relationship is unsettled for two-dimensional and quasi-two-dimensional lead-halide perovskites. One possibility assumes that excitons are the dominant photoexcited population and therefore that the emitter number scales linearly with fluence; another assumes that free carriers form only a minority exciton population, yielding a different scaling such as the quadratic relation used in prior work.

Resolving the microscopic carrier composition would clarify how to interpret fluence-dependent superfluorescence intensity, delay times, and burst widths, and would determine which scaling law should be used to compare experiments with Dicke or modified Maxwell–Bloch models.