Exciplex formations at the HTL/Alq3 interface in an organic light-emitting diode: Influence of the electron-hole recombination zone and electric field

Naoki Matsumoto, Chihaya Adachi

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21 Citations (Scopus)

Abstract

In this work, we investigate the influence of weak intermolecular interactions, which have not previously been carefully considered, in hole transport material (HTM)/tris(8-hydroxyquinoline)aluminum (Alq 3)-based organic light-emitting diodes (OLEDs). Although such weak interactions quench Alq3 fluorescence, no significant spectral shift is identified. Electroluminescence of OLEDs containing HTM:Alq3 codeposited (mixed) emitter is quenched by the formation of such exciplexes. In general, the electroluminescence quantum efficiency of OLEDs correlates closely with the photoluminescence quantum yields of HTM:Alq3 codeposited films. In contrast, in an OLED containing a layered structure of HTM/Alq 3, exciplexes are less effective at quenching the electroluminescence of Alq3. Because exciplexes form only at the interface between the HTM and Alq3 layers in HTM/Alq3-based OLEDs, exciplex formation is affected not only by the electron donating nature of the HTM but also by the position of the electron-hole recombination zone and the application of an external electric field during OLED operation.

Original languageEnglish
Pages (from-to)4652-4658
Number of pages7
JournalJournal of Physical Chemistry C
Volume114
Issue number10
DOIs
Publication statusPublished - Mar 18 2010

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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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