Theory of low-field hopping mobility in organic solids with energetic and positional disorder

The influence of superimposed energetic and positional disorder on the field dependence of drift mobility in disordered organic solids is considered for the first time analytically by an Effective Medium theory. We find that the negative field dependence of the drift mobility at low fields is a genuine property of the nondispersive hopping transport in three-dimensional disordered organic solids and caused by positional disorder. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)