The role of orientation in the MEL response of OLEDs

Sebastian Engmann, Emily G. Bittle, Lee J. Richter, Rawad K. Hallani, John E. Anthony, David J. Gundlach

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Magneto electroluminescence (MEL) is emerging as a powerful tool to study spin dynamics in organic light emitting diodes (OLEDs). The shape of the MEL response is typically used to draw qualitative inference on the dominant process (singlet fission or triplet fusion) in the device. In this study, we develop a quantitative model for MEL and apply it to devices based on rubrene, and three solution processable anthradithiophene emitters. The four emitters allow us to systematically vary the film structure between highly textured, poly-crystalline to amorphous. We find significant diversity in the MEL, with the textured films giving highly structured responses. We find that the additional structure does not coincide with energy anti-crossings, but intersections in the singlet character between adjacent states. In all cases the MEL can be adequately described by an extended Merrifield model.Viathe inclusion of charge injection, we are able to draw additional information on underlying physics in OLED devices.

Original languageEnglish
Pages (from-to)10052-10064
Number of pages13
JournalJournal of Materials Chemistry C
Volume9
Issue number31
DOIs
StatePublished - Aug 21 2021

Bibliographical note

Funding Information:
S. E. acknowledges support from the U.S. Department of Commerce, National Institute of Standards and Technology under the financial assistance award 70NANB17H305. J. E. A. and R. K. H. acknowledge support from the National Science Foundation, award DMREF-1627428. X-Ray scattering measurements were carried out at the CMS beamline of the National Synchrotron Light Source II (NSLS II), a U.S. Department of Energy (DOE) office of the Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory. We thank Dr Ruipeng Li and Dr Masafumi Fukuto for their assistance with X-ray scattering measurements at NSLS II.

Publisher Copyright:
© The Royal Society of Chemistry 2021.

ASJC Scopus subject areas

  • Chemistry (all)
  • Materials Chemistry

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