4-AcNI - a new polymer for light-emitting diodes

We report investigations on a 4-acetamido-substituted naphthalimide polymer (4-AcNI) as a component for light-emitting diodes (LEDs). Devices prepared with 4-AcNI as the active material are relatively inefficient (4 x 10(-4)%). Higher internal quantum efficiency values of 0.4% are achieved if 4-AcNI is used as an electron-transporting layer (ETL) in devices which use poly(p-phenylene vinylene) (PPV) as a hole transport layer. For Al cathodes, this material proves to be superior to similar devices which use 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as the ETL. The results are used to shed some light on the function of ETLs in organic LEDs. (C) 1998 Elsevier Science S.A. All rights reserved.