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Title: Tuning magnetoresistance and magnetic-field-dependent electroluminescence through mixing a strong-spin-orbital-coupling molecule and a weak-spin-orbital-coupling polymer

Abstract

We report a tunable magnetoresistance by uniformly mixing strong-spin-orbital-coupling molecule fac-tris (2-phenylpyridinato) iridium [Ir(ppy)3] and weak-spin-orbital-coupling polymer poly(N-vinyl carbazole) (PVK). Three possible mechanisms, namely charge transport distribution, energy transfer, and intermolecular spin-orbital interaction, are discussed to interpret the Ir(ppy)3 concentration-dependent magnetoresistance in the PVK+Ir(ppy)3 composite. The comparison between the magnetic field effects measured from energy-transfer and non-energy-transfer Ir(ppy)3 doped polymer composites indicates that energy transfer and intermolecular spin-orbital interaction lead to rough and fine tuning for the magnetoresistance, respectively. Furthermore, the photocurrent dependence of magnetic field implies that the excited states contribute to the magnetoresistance through dissociation. As a result, the modification of singlet or triplet ratio of excited states through energy transfer and intermolecular spin-orbital interaction form a mechanism to tune the magnetoresistance in organic semiconducting materials.

Authors:
 [1];  [1];  [1];  [2]
  1. University of Tennessee, Knoxville (UTK)
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Temperature Materials Laboratory
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
932161
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 75; Journal Issue: 3
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; IRIDIUM COMPLEXES; POLYVINYLS; CARBAZOLES; POLYMERS; L-S COUPLING; MIXING; COMPOSITE MATERIALS; CHARGE TRANSPORT; ELECTROLUMINESCENCE; ENERGY TRANSFER; MAGNETORESISTANCE; TUNING; EXCITED STATES; DISSOCIATION; SEMICONDUCTOR MATERIALS

Citation Formats

Wu, Yue, Xu, Zhihua, Hu, Bin, and Howe, Jane Y. Tuning magnetoresistance and magnetic-field-dependent electroluminescence through mixing a strong-spin-orbital-coupling molecule and a weak-spin-orbital-coupling polymer. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.75.035214.
Wu, Yue, Xu, Zhihua, Hu, Bin, & Howe, Jane Y. Tuning magnetoresistance and magnetic-field-dependent electroluminescence through mixing a strong-spin-orbital-coupling molecule and a weak-spin-orbital-coupling polymer. United States. doi:10.1103/PhysRevB.75.035214.
Wu, Yue, Xu, Zhihua, Hu, Bin, and Howe, Jane Y. Mon . "Tuning magnetoresistance and magnetic-field-dependent electroluminescence through mixing a strong-spin-orbital-coupling molecule and a weak-spin-orbital-coupling polymer". United States. doi:10.1103/PhysRevB.75.035214.
@article{osti_932161,
title = {Tuning magnetoresistance and magnetic-field-dependent electroluminescence through mixing a strong-spin-orbital-coupling molecule and a weak-spin-orbital-coupling polymer},
author = {Wu, Yue and Xu, Zhihua and Hu, Bin and Howe, Jane Y},
abstractNote = {We report a tunable magnetoresistance by uniformly mixing strong-spin-orbital-coupling molecule fac-tris (2-phenylpyridinato) iridium [Ir(ppy)3] and weak-spin-orbital-coupling polymer poly(N-vinyl carbazole) (PVK). Three possible mechanisms, namely charge transport distribution, energy transfer, and intermolecular spin-orbital interaction, are discussed to interpret the Ir(ppy)3 concentration-dependent magnetoresistance in the PVK+Ir(ppy)3 composite. The comparison between the magnetic field effects measured from energy-transfer and non-energy-transfer Ir(ppy)3 doped polymer composites indicates that energy transfer and intermolecular spin-orbital interaction lead to rough and fine tuning for the magnetoresistance, respectively. Furthermore, the photocurrent dependence of magnetic field implies that the excited states contribute to the magnetoresistance through dissociation. As a result, the modification of singlet or triplet ratio of excited states through energy transfer and intermolecular spin-orbital interaction form a mechanism to tune the magnetoresistance in organic semiconducting materials.},
doi = {10.1103/PhysRevB.75.035214},
journal = {Physical Review B},
number = 3,
volume = 75,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}