Signatures of exciton dynamics and carrier trapping in the time-resolved photoluminescence of colloidal cdse nanocrystals

Marcus Jones, Shun S. Lo, Gregory D. Scholes

Research output: Contribution to journalArticle

113 Scopus citations

Abstract

Surface effects significantly affect the photoexcitation dynamics of colloidal nanocrystals, but their influence is hard to study because of sample complexity and the typically small extinction coefficient of trap states. Using temperature-dependent time-resolved photoluminescence (PL) measurements, we investigate the perturbations induced by surface-localized carrier traps on the exciton dynamics of the nanocrystals. We present a model of carrier trapping that is based on Marcus' electron-transfer theory and use it to accurately reproduce PL dynamics over a wide temperature range in five core-shell CdSe/CdZnS nanocrystal samples. The resulting pictures of carrier dynamics are then used to identify features in the PL data that may be used in subsequent experiments to reveal information about the energy and distribution of surface-localized trap states. We find that in certain cases, the shape of the ensemble distribution of trap energies can be accurately determined from data recorded at a single temperature that is easily identified from plots of average PL lifetime.

Original languageEnglish (US)
Pages (from-to)18632-18642
Number of pages11
JournalJournal of Physical Chemistry C
Volume113
Issue number43
DOIs
StatePublished - Nov 20 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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