Frequency dependent carrier mobility in polymer LED's

The charge mobility in polymer LED's depends on the polymer and its packing . In the latter various length scales play a role. To study this aspect, we performed dielectric spectroscopy as function of electric field and temper ature on OC1C10-poly(p-phenylene vinylene). At low frequencies the mobility (mu) is mainly determined by the energetic disorder of the weakest link. A round 100 GHz mu has increased by 6 orders of magnitude and the field depen dence has changed significantly. At these high frequencies, which in this c ase are representative for the pair limit, the field dependence shows that still appreciable energy barriers have to be overcome. Together these data allow a detailed characterization of the charge transport in the LED.