THE DIELECTRIC RESPONSE OF 8-HYDROXYQUINOLINE ALUMINUM USED IN MULTILAYER ORGANIC DEVICES

摘要

We present optical measurements of 8-hydroxyquinoline aluminum (Akq_3) a metal-chelate complex which is an important material used for multilayer light emitting diodes. Thin films of Alq_3 produced by vacuum deposition were investigated by transmission and reflectance spectroscopy, and the dielectric coefficients in the near IR to UV-Vis energy range were calculated. Kramers-Kronig analysis was used to determine the real and imaginary dielectric spectral dependence of the thin films. Values obtained by internal field distribution measurements in organic double layer LED's are compared to those determined from optical data. A near-IR value of epsilon (real component) close to 3 was obtained from optical measurements.