Libai Huang1
Purdue University1
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 exciton delocalization and transport in perovskite QD SLs. Through temperature-dependent and time-resolved photoluminescence microscopy measurements, we demonstrate coherent exciton propagation in highly ordered SLs. We unravel the effect of disorder by comparing SLs with varying degrees of inhomogeneity. Our results point to the exciting opportunities in engineering exciton coherence in perovskite solids.