4-ACNI - A NEW POLYMER FOR LIGHT-EMITTING-DIODES

We report investigations on a 4-acetamido-substituted naphthalimide po lymer (4-AcNI) as a component for light-emitting diodes (LEDs). Device s prepared with 4-AcNI as the active material are relatively inefficie nt (4 x 10(-4)%). Higher internal quantum efficiency values of 0.4% ar e achieved if 4-AcNI is used as an electron-transporting layer (ETL) i n devices which use poly(p-phenylene vinylene) (PPV) as a hole transpo rt layer. For Al cathodes, this material proves to be superior to simi lar devices which use iphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazo le (PBD) as the ETL. The results are used to shed some light on the fu nction of ETLs in organic LEDs. (C) 1998 Elsevier Science S.A. All rig hts reserved.