Nondispersive electron transport in Alq3

We have studied room temperature electron transport in amorphous films of tris (8-hydroxyquinolinolato) aluminum (III) (Alq(3)) with the time-of-flight technique. Nondispersive photocurrent transients indicate the absence of intrinsic traps in well-purified films. Exposure of the films to ambient atmosphere results in highly dispersive transport, indicating that oxygen is a likely candidate for a trapping site. The mobility was found to obey the Poole-Frenkel law. We use the correlated disorder model to determine an effective dipole moment for Alq(3), and the corresponding meridional to facial isomeric ratio. (C) 2001 American Institute of Physics.