Colloidal CdSe nanocrystals are inherently defective

Tamar Goldzak, Alexandra R. McIsaac, Troy Van Voorhis

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Colloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.

Original languageEnglish
Article number890
JournalNature Communications
Volume12
Issue number1
DOIs
StatePublished - 9 Feb 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).

Funding

This work was supported by the Department of Energy under grant number DMR-1905164. This work used the Extreme Science and Engineering Discovery Environment (XSEDE) resource Comet at the San Diego Supercomputing Center through allocation TG-DMR190054, which is supported by National Science Foundation grant number ACI-1548562. T.G. received financial support from the Technion-MIT fellowship and the Technion-New England Foundation. A.R.M. was supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1122374.

FundersFunder number
Technion-MIT
Technion-New England Foundation
National Science FoundationACI-1548562
U.S. Department of EnergyDMR-1905164
Directorate for Education and Human Resources1122374

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