Unoccupied molecular orbital states of tris (8-hydroxy quinoline) aluminum: Observation and dynamics

Electrons photoexcited into the normally unoccupied states of vacuum deposited thin films of tris (8-hydroxy quinoline) aluminum (Alq) have been studied with excite-probe harmonic laser photoemission. Both valence and transiently excited empty states are observed. A surface recombination velocity of 75±30 cm/s has been determined. © 1997 American Institute of Physics.