Antagonistic responses between magnetoconductance and magnetoelectroluminescence in polymer light-emitting diodes

Kai Wei Tsai, Tsung Hsun Lee, Jin Han Wu, Jing Yuan Jhou, Wei Shun Huang, Sung Nien Hsieh, Ten Chin Wen, Tzung Fang Guo, J. C.A. Huang

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Antagonistic responses between magnetoconductance (MC) and magnetoelectroluminescence (MEL) in the polymer light-emitting diodes with an interfacial layer between Al cathode and active layer are simultaneously measured. As the interfacial layer (tetraoctylammonium bromide) is used, the significant increase in the number of injected negative polarons and the blocking of positive polarons promote the triplets-(free polaron) reaction and provide a good explanation for the reason that electroluminescence (EL) efficiency is maximal in the trap free space charge limited current regime at high bias. By fitting of MC and MEL curves using Lorentzian and non-Lorentzian empirical equations, three magnetic field dependent mechanisms, which are the intersystem crossing between singlet/triplet polaron pairs, the triplets-(free polaron) reaction, and the triplets-(trapped polaron) reaction are elucidated. The distribution of the three components is tunable by varying the applied electric field, which primarily modulates the triplets-(free polaron) reaction rate. The results pave a new route toward understanding the mechanism of organic spintronics for developing of multifunctional devices.

Original languageEnglish
Pages (from-to)1376-1382
Number of pages7
JournalOrganic Electronics
Volume14
Issue number5
DOIs
Publication statusPublished - 2013 May

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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