| Abstract: | We report on magnetic field effects in organic light emitting diodes made of homopolymer active layers in magnetic fields up to 8 T. The measurements on bias driven devices include magneto-condoctance and magneto-electroluminescence. We also studied magneto-photoconductance and magnetophotoluminescence in optically excited devices. In the very low magnetic field regime (B<~10 mT) we find that the main mechanism responsible for the magneto-effects is the hyperfine interaction between the charge carriers and protons. The high field response is dominated by the anisotropic g-tensor and thermal spin polarization. We developed a simplified quantum mechanical approach taking into the above interactions in order to account for the experimental data. |
