Chemical control of the photoluminescence of CdSe quantum dot-organic complexes with a series of para-substituted aniline ligands

Kathryn E. Knowles, Daniel B. Tice, Eric A. McArthur, Gemma C. Solomon, Emily A. Weiss

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Abstract

Replacement of the native (as-synthesized) ligands of colloidal CdSe QDs with varying concentrations of a series of para-substituted anilines (R-An), where R ranges from strongly electronwithdrawing to strongly electron-donating, decreases the PL of the QDs. The molar ratio of R-An to QD ([R-An]:[QD]) at which the PL decreases by 50% shifts by 4 orders of magnitude over the series R-An. The model employed to describe the data combines a Freundlich binding isotherm (which reflects the dependence of the binding affinity of the amine headgroups of R-An on the substituent R) with a function that describes the response of the PL to R-An ligands once they are bound at their equilibrium surface coverage. The latter function includes as a parameter the rate constant, knr, for nonradiative decay of the exciton at a site to which an R-An ligand is coordinated. The value of this parameter reveals that the predominant mechanism of QD-ligand interaction is passivation of Cd2+ surface sites through σ-donation for R-An ligands with R ) H, Br, OCF3, and reductive quenching through photoinduced hole transfer for R = MeO, (Me)2N.

Original languageEnglish
Pages (from-to)1041-1050
Number of pages10
JournalJournal of the American Chemical Society
Volume132
Issue number3
DOIs
Publication statusPublished - Feb 12 2010

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ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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