Control over exciton confinement versus separation in composite films of polyfluorene and CdSe nanocrystals

Y. C. Tseng, M. Tzolov, E. H. Sargent, P. W. Cyr, M. A. Hines

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Composite films of polyfluorene derivative poly(9,9-di-(2-ethylhexyl)- fluorenyl-2,7-diyl) and cadmium selenide nanocrystals were investigated using photomodulation spectroscopy exciting only the nanocrystal phase. Efficient charge separation resulting in hole injection into the polymer was observed in films in which the nanocrystals had been stripped of surface trioctylphosphine oxide passivating groups. The resulting induced absorption band centered at 1.2 eV was assigned to bipolarons or π-dimers formed on the polymer in the near vicinity of the polymer/nanocrystal interface. The intensity dependence of this band suggests bimolecular recombination, supporting the interpretation of the band as due to charge separation. The measured wide distribution of lifetimes for the photogenerated states confirms the glassy nature of the polymer.

Original languageEnglish (US)
Pages (from-to)3446-3448
Number of pages3
JournalApplied Physics Letters
Volume81
Issue number18
DOIs
StatePublished - Oct 28 2002

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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