Magnetoelectroluminescence of organic heterostructures: Analytical theory and spectrally resolved measurements
- Univ. of Minnesota, Minneapolis, MN (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Minnesota, Minneapolis, MN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
The effect of a magnetic field on the electroluminescence of organic light emitting devices originates from the hyperfine interaction between the electron/hole polarons and the hydrogen nuclei of the host molecules. In this paper, we present an analytical theory of magnetoelectroluminescence for organic semiconductors. To be specific, we focus on bilayer heterostructure devices. In the case we are considering, light generation at the interface of the donor and acceptor layers results from the formation and recombination of exciplexes. The spin physics is described by a stochastic Liouville equation for the electron/hole spin density matrix. By finding the steady-state analytical solution using Bloch-Wangsness-Redfield theory, we explore how the singlet/triplet exciplex ratio is affected by the hyperfine interaction strength and by the external magnetic field. In order to validate the theory, spectrally resolved electroluminescence experiments on BPhen/m-MTDATA devices are analyzed. With increasing emission wavelength, the width of the magnetic field modulation curve of the electroluminescence increases while its depth decreases. Furthermore, these observations are consistent with the model.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- DMR-0819885; AC52-06NA25396
- OSTI ID:
- 1235729
- Alternate ID(s):
- OSTI ID: 1181137
- Report Number(s):
- LA-UR-14-28083; PRBMDO
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 90, Issue 23; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Direct observation of reverse intersystem crossing from fully confined triplet exciplexes using magneto-electroluminescence
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journal | January 2019 |
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