Resolving the Triexciton Recombination Pathway in CdSe/CdS Nanocrystals through State-Specific Correlation Measurements

Katherine E. Shulenberger, Sophie C. Coppieters'T Wallant, Megan D. Klein, Alexandra R. McIsaac, Tamar Goldzak, David B. Berkinsky, Hendrik Utzat, Ulugbek Barotov, Troy Van Voorhis, Moungi G. Bawendi

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

As luminescence applications of colloidal semiconductor nanocrystals push toward higher excitation flux conditions, there is an increased need to both understand and potentially control emission from multiexciton states. We develop a spectrally resolved correlation method to study the triply excited state that enables direct measurements of the recombination pathway for the triexciton, rather than relying on indirect extraction of rates. We demonstrate that, for core-shell CdSe-CdS nanocrystals, triexciton emission arises exclusively from the band-edge S-like state. Time-dependent density functional theory and extended particle-in-a-sphere calculations demonstrate that reduced carrier overlap induced by the core-shell heterostructure can account for the lack of emission observed from the P-like state. These results provide a potential avenue for the control of nanocrystal luminescence, where core-shell heterostructures can be leveraged to control carrier separation and therefore maintain emission color purity over a broader range of excitation fluxes.

Original languageEnglish
Pages (from-to)7457-7464
Number of pages8
JournalNano Letters
Volume21
Issue number18
DOIs
StatePublished - 22 Sep 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society.

Funding

This work was supported primarily by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award DE-FG02-07ER46454 [K.E.S. (lead author, data collection, analysis and interpretation, software development), S.C.C. (colead author, data collection, analysis, software development), and H.U. (software development)]. M.D.K. (data collection, particle-in-a-sphere modeling) and A.R.M. (TDDFT calculations and interpretation) were supported by the National Science Foundation Graduate Research Fellowship Program Under Grant 1122374. T.G. (TDDFT calculations and interpretation) was supported by the Technion-MIT fellowship and the Technion-New England Foundation. U.B. (sample characterization) was supported by DSM research. D.B.B. (heterogeneity characterization) was support by Samsung SAIT. The computational work (A.R.M. and T.G.) was supported by the US Department of Energy, Office of Basic Energy Sciences (Award DE-FG02-07ER46474). We would also like to acknowledge Professor William A. Tisdale of the Chemical Engineering Department at Massachusetts Institute of Technology for both productive discussions as well as the use of synthetic laboratory space.

FundersFunder number
Technion-MIT
Technion-New England Foundation
National Science Foundation1122374
U.S. Department of Energy
Office of Science
Basic Energy SciencesDE-FG02-07ER46454, DE-FG02-07ER46474
Diagnostic Services Manitoba

    Keywords

    • multiexcitons
    • nanocrystals
    • photoluminescence
    • quantum dots
    • single-molecule spectroscopy
    • triexcitons

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