Theoretical investigation on magnetic field effect in organic devices with asymmetrical molecules

Abstract

A mechanism of organic magnetic field effect (OMFE) based on Lorentz effect in organic light-emitting devices with asymmetrical molecules is suggested and the magnetoconductance (MC) value is calculated. By considering the collision of a positive and a negative charged polaron and exciton formation in the organic layer through a non-adiabatic dynamic process, it is found that the exciton yield can be changed by applying a magnetic field due to the Lorentz effect on the moving polarons’ phase factors. By calculating the current through the device and the MC, we obtain that the calculated MC is well consistent to some experimental observations. It is also found that the MC value is sensitive to the asymmetrical structure and the electron–phonon (e–ph) coupling of the organic material, which explains why magnetic effect in an organic semiconductor is much more apparent than its inorganic counterpart.