Boosting quantum efficiency of single layer organic light emitting device by doping CoFe magnetic nanoparticles.

ORAL

Abstract

The effects of doping magnetic CoFe nanoparticles on electroluminance (EL) efficiency vs. current density, and current density vs. applied voltage for single layer organic light emitting devices (OLEDs) have been investigated. The electron trap densities increased with the increase of CoFe dopants, resulting in a high trap-filled limit (TFL) threshold voltage and significant enhancement EL efficiency ($\sim $27{\%}). The EL efficiencies were further improved ($\sim $5-7{\%}) by applied magnetic field. These improvements could be attributed to the enhancements of the ratios of the formation of excitons, and singlets to triplets, respectively and simultaneously. A maximum 32{\%} enhancement combing the two effects in EL efficiency has been achieved.

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Authors

  • Chengjun Sun

    Materials Science and Technology Division, Oak Ridge National Laboratory

  • Yue Wu

    Department of Materials Science and Engineering, University of Tennessee

  • Zhihua Xu

    Department of Materials Science and Engineering, University of Tennessee

  • Bin Hu

    University of Tennessee, Department of Materials Science and Engineering, University of Tennessee

  • Jian-Ping Wang

    The Center for MINT, and Department of ECE, University of Minnesota

  • J. Shen

    Material Science and Technology Division and Center for Nanophase Materials Science Division, Oak Ridge National Laboratory, ORNL and Univ of Tennessee