Optical properties and exciton dynamics of alloyed core/shell/shell Cd 1-xZnxSe/ZnSe/ZnS quantum dots

Bob C. Fitzmorris, Ying Chih Pu, Jason K. Cooper, Yi Fang Lin, Yung-Jung Hsu*, Yat Li, Jin Z. Zhang

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

63 Scopus citations

Abstract

In this study we introduce a new method for the one-pot synthesis of core/shell/shell alloyed Cd1-xZnxSe/ZnSe/ZnS QDs and examine the effect of the shell coating on the optical properties and exciton dynamics of the alloy core. The photoluminescence (PL) quantum yield is greatly enhanced after shell growth, from 9.6% to 63%. The exciton dynamics were studied by time correlated single photon counting (TCSPC) and fit using integrated singular value decomposition global fitting (i-SVD-GF), which showed the biexponential observed lifetimes on the nanosecond time scale remain the same after shell growth. Using ultrafast transient absorption (TA) spectroscopy and SVD-GF, we have determined that surface passivation by ZnSe and ZnSe/ZnS shells reduces nonradiative recombination primarily on the picosecond time scale. These findings are helpful in directing the development of the next generation of QDs for biological labeling and other applications.

Original languageEnglish
Pages (from-to)2893-2900
Number of pages8
JournalACS Applied Materials and Interfaces
Volume5
Issue number8
DOIs
StatePublished - 24 Apr 2013

Keywords

  • CdSe
  • ZnS
  • ZnSe
  • alloy
  • biological labeling
  • core/shell
  • core/shell/shell
  • dynamics
  • exciton
  • fluorescence
  • photoluminescence
  • quantum dot
  • quantum yield
  • shell
  • time-resolved
  • transient absorption
  • ultrafast

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