Time-of-Flight Measurement of Hole Mobility in Aluminum (III) Complexes

We measured hole drift mobility in vacuum-deposited films of aluminum (III) complexes, tris (8-quinolinolato) aluminum (III) (Alq 3 ), tris (8-phenanthridinolato) aluminum (III) (Alph 3 ) and tris (4-methyl-8-quinolinolato) aluminum (III) (Almq 3 ), using a time-of-flight technique. Hole transport was nondispersive for Alq 3 and dispersive for Alph 3 and Almq 3 . The hole mobilities of these aluminum complexes were of the order of 10 -10 –10 -8 cm 2 /V·s and were largely dependent on the electric field.