Organic magnetic-field effect examined in frequency domain and time domain

Recent work has shown that weak applied magnetic fields of several tens of mT can lead to a change of several percent in the (photo)conductivity of organic semiconductor devices. However, it remains to be determined whether the applied magnetic field modifies the (photo)carrier density, their mobility or both. We use magneticfield- dependent time-of-flight spectroscopy to disentangle these two possibilities. We find evidence that the magnetic field leads to a decrease in the photocarrier time-of-flight. We also examine organic magnetoresistive devices in the frequency domain to complete the characterization of the time-dependent field-effect response.