PHOTOCONDUCTION IN POLY(3-ALKYLTHIOPHENE) .2. CHARGE TRANSPORT

Hole motion in poly(dodecylthiophene) has been investigated by means o f time of flight (TOF) studies and space charge limited conduction inv olving hole injection from a gold anode. The decrease of the hole mobi lity with temperature above 290 K parallels the increase of disorder m anifest in the absorption spectra. At lower temperatures TOF signals b ecome dispersive. The results are interpreted in terms of hopping moti on within an energetically random array of hopping sites formed by ord ered chain segments. The polaron contribution towards the activation e nergy for charge carrier motion is found negligible relative to the di sorder contribution.