Enhanced Luminescent Stability through Particle Interactions in Silicon Nanocrystal Aggregates

Joseph B. Miller, Naveen Dandu, Kirill A. Velizhanin, Rebecca J. Anthony, Uwe R. Kortshagen, Daniel M. Kroll, Svetlana Kilina, Erik K. Hobbie

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Close-packed assemblies of ligand-passivated colloidal nanocrystals can exhibit enhanced photoluminescent stability, but the origin of this effect is unclear. Here, we use experiment, simulation, and ab initio computation to examine the influence of interparticle interactions on the photoluminescent stability of silicon nanocrystal aggregates. The time-dependent photoluminescence emitted by structures ranging in size from a single quantum dot to agglomerates of more than a thousand is compared with Monte Carlo simulations of noninteracting ensembles using measured single-particle blinking data as input. In contrast to the behavior typically exhibited by the metal chalcogenides, the measured photoluminescent stability shows an enhancement with respect to the noninteracting scenario with increasing aggregate size. We model this behavior using time-dependent density functional theory calculations of energy transfer between neighboring nanocrystals as a function of nanocrystal size, separation, and the presence of charge and/or surface-passivation defects. Our results suggest that rapid exciton transfer from 'bright' nanocrystals to surface trap states in nearest-neighbors can efficiently fill such traps and enhance the stability of emission by promoting the radiative recombination of slowly diffusing excited electrons.

Original languageEnglish (US)
Pages (from-to)9772-9782
Number of pages11
JournalACS nano
Volume9
Issue number10
DOIs
StatePublished - Oct 27 2015

Keywords

  • energy transfer
  • fluorescence intermittency
  • nanocrystal interactions
  • silicon nanocrystals

How much support was provided by MRSEC?

  • Primary

Reporting period for MRSEC

  • Period 2

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.

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