Correlating the lifetime and fluorine content of iridium(III) emitters in green light-emitting electrochemical cells

Research output: Contribution to journalArticlepeer-review

Authors

  • Daniel Tordera
  • Juan J. Serrano-Pérez
  • Antonio Pertegás
  • Enrique Ortí
  • Henk J. Bolink
  • Md Khaja Nazeeruddin
  • Julien Frey

Colleges, School and Institutes

External organisations

  • Ecole Polytechnique Federale de Lausanne
  • Instituto de Ciencia Molecular, Universidad de Valencia

Abstract

In light-emitting electrochemical cells, the lifetime of the device is intrinsically linked to the stability of the phosphorescent emitter. In this study, we present a series of ionic iridium(III) emitters based on cyclometalating phenylpyridine ligands whose fluorine substituents are varied in terms of position and number. Importantly, despite these structural modifications, the emitters exhibit virtually identical electrochemical and spectroscopic properties, which allows for proper comparison in functional devices. Quantum-chemical calculations support the properties measured in solution and suggest great similarities regarding the electronic structures of the emitters. In electroluminescent devices, the initial luminance, efficiency, and efficacy are also relatively unaffected throughout the series. However, a shorter device lifetime is obtained upon increasing the fluorine content of the emitter, which suggests drawbacks of such electron-withdrawing substituents for the design of ionic iridium(III) emitters.

Details

Original languageEnglish
Pages (from-to)3391-3397
Number of pages7
JournalChemistry of Materials
Volume25
Issue number16
Publication statusPublished - 27 Aug 2013

Keywords

  • electroluminescent devices, iridium emitters, stability