Efficient and long-living light-emitting electrochemical cells

Rubén D. Costa, Enrique Ortí, Henk J. Bolink, Stefan Graber, Catherine E. Housecroft, Edwin C. Constable

Research output: Contribution to journalArticle

129 Citations (Scopus)

Abstract

Three new heteroleptic iridium complexes that combine two approaches, one leading to a high stability and the other yielding a high luminescence efficiency, are presented. All complexes contain a phenyl group at the 6-position of the neutral bpy ligand, which holds an additional, increasingly bulky substituent on the 4-position. The phenyl group allows for intramolecular π-π stacking, which renders the complex more stable and yields long-living light-emitting electrochemical cells (LECs). The additional substituent increases the intersite distance between the cations in the film, reducing the quenching of the excitons, and should improve the efficiency of the LECs. Density functional theory calculations indicate that the three complexes have the desired π-π intramolecular interactions between the pendant phenyl ring of the bpy ligand and the phenyl ring of one of the ppy ligands in the ground and the excited states. The photoluminescence quantum efficiency of concentrated films of the complexes improves with the increasing size of the bulky groups indicating that the adopted strategy for improving the efficiency is successful. Indeed, LEC devices employing these complexes as the primary active component show shorter turn-on times, higher efficiencies and luminances, and, surprisingly, also demonstrate longer device stabilities.

Original languageEnglish
Pages (from-to)1511-1520
Number of pages10
JournalAdvanced Functional Materials
Volume20
Issue number9
DOIs
Publication statusPublished - 2010 May 10

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrochemistry

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  • Cite this

    Costa, R. D., Ortí, E., Bolink, H. J., Graber, S., Housecroft, C. E., & Constable, E. C. (2010). Efficient and long-living light-emitting electrochemical cells. Advanced Functional Materials, 20(9), 1511-1520. https://doi.org/10.1002/adfm.201000043