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  • A composite electrodynamic mechanism to reconcile spatiotemporally resolved exciton transport in quantum dot superlattices
Title: A composite electrodynamic mechanism to reconcile spatiotemporally resolved exciton transport in quantum dot superlattices
Quantum dot (QD) solids are promising optoelectronic materials; further advancing their device functionality requires understanding their energy transport mechanisms. The commonly invoked near-field Förster resonance energy transfer (FRET) theory often underestimates the exciton hopping rate in QD solids, yet no consensus exists on the underlying cause. In response, we use time-resolved ultrafast stimulated emission depletion (STED) microscopy, an ultrafast transformation of STED to spatiotemporally resolve exciton diffusion in tellurium-doped cadmium selenide–core/cadmium sulfide–shell QD superlattices. We measure the concomitant time-resolved exciton energy decay due to excitons sampling a heterogeneous energetic landscape within the superlattice. The heterogeneity is quantified by single-particle emission spectroscopy. This powerful multimodal set of observables provides sufficient constraints on a kinetic Monte Carlo simulation of exciton transport to elucidate a composite transport mechanism that includes both near-field FRET and previously neglected far-field emission/reabsorption contributions. Uncovering this mechanism offers a much-needed unified framework in which to characterize transport in QD solids and additional principles for device design.  more » « less
Award ID(s):
1954393
PAR ID:
10488449
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
Science
Date Published:
Journal Name:
Science Advances
Volume:
9
Issue:
42
ISSN:
2375-2548
Page Range / eLocation ID:
eadh2410
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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