Nondispersive electron transport in Alq(3)

We have studied room temperature electron transport in amorphous films of t ris (8-hydroxyquinolinolato) aluminum (III) (Alq(3)) with the time-of-fligh t technique. Nondispersive photocurrent transients indicate the absence of intrinsic traps in well-purified films. Exposure of the films to ambient at mosphere 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 eff ective dipole moment for Alq(3), and the corresponding meridional to facial isomeric ratio. (C) 2001 American Institute of Physics.