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

Autor: Shulenberger KE; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Coppieters 't Wallant SC; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Klein MD; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., McIsaac AR; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Goldzak T; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Berkinsky DB; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Utzat H; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Barotov U; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Van Voorhis T; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States., Bawendi MG; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Jazyk: angličtina
Zdroj: Nano letters [Nano Lett] 2021 Sep 22; Vol. 21 (18), pp. 7457-7464. Date of Electronic Publication: 2021 Sep 13.
DOI: 10.1021/acs.nanolett.0c05109
Abstrakt: 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.
Databáze: MEDLINE
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