Effect of g-factor anisotropy in the magnetoresponse of organic light-emitting diodes at high magnetic fields

We report the magnetic field and temperature dependences of magnetoconductance (MC) and magnetoelectroluminescence (MEL) in organic light emitting diodes (OLED) made of homopolymer organic layers. We show that in these OLEDs a spin mixing mechanism due to the anisotropy of the organic layer g factor has a significant effect in the measured MC(B) and MEL(B) at fields of order of ∼1T. We discuss the model of spin mixing among polaron pairs due to the anisotropy of the g factor and show that it can be described as an angle dependent Δg mechanism that is known to have significant magnetoresponse effects. We show that the internal structure of the polaron pair is material dependent rationalizing thus the differences in their electrical mobility.