The performance of quantum dot (QD) devices in optoelectronic and quantum information applications relies on not only the properties of the individual QDs but also the collective properties arising from interactions between QDs within a solid. The interactions between QDs determine whether long-range coherence and transport can be achieved. Due to their large oscillator strengths, perovskite QD superlattices (SLs) have the potential for exciton superradiance. However, the ultrafast dephasing processes can limit their coherence lengths. We provide a detailed study on the key factors that control superradiance in perovskite QD SLs. Through temperature-dependent and time-resolved photoluminescence measurements, we determine the relationship between exciton superradiance and dephasing processes, including those by static disorder and phonon scattering. We unravel the effect of disorder by comparing SLs with varying degrees of inhomogeneity. Our results contribute to a better understanding of the interplay between electronic coupling strength and the degree static and dynamic disorder in achieving superradiance in QD solids.

Disorder and phonon limited superradiance in perovskite quantum dot superlattices

ACS Spring 2022

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