Fast dissociation and reduced auger recombination of multiple excitons in closely packed PBS nanocrystal thin films

Taishi Nishihara, Hirokazu Tahara, Makoto Okano, Masashi Ono, Yoshihiko Kanemitsu

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Exciton decay dynamics in chemically treated PbS quantum-dot (QD) films have been studied using femtosecond transient-absorption (TA) spectroscopy. In photoconductive QD films, a decay component with a lifetime of a few nanoseconds appeared in the TA signals because of exciton dissociation under weak excitation. Increasing excitation fluence resulted in additional fast-decay components corresponding to the lifetimes of multiple excitons, which decreased with increasing photoconductivity of the closely packed QD films. Auger recombination in photoexcited QDs was suppressed in highly photoconductive films. Our findings clearly show that the carrier transfer between the QDs dominates the lifetimes of single and multiple excitons.

Original languageEnglish
Pages (from-to)1327-1332
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume6
Issue number8
DOIs
Publication statusPublished - 2015 Apr 16
Externally publishedYes

Keywords

  • Auger recombination
  • exciton dissociation
  • multiple exciton generation
  • quantum dot film
  • transient absorption

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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