FAILURE MODES IN POLYMER-BASED LIGHT-EMITTING-DIODES

Polymeric electroluminescent devices are now being made that achieve l ifetimes of several thousands of hours at room temperature, and are pr obably nearing commercial appearance. This article reviews what has be en learned about how to achieve these lifetimes, and considers what mu st still be done in order to extend them. Degradation processes discus sed include formation of non-emissive spots due to cathode reaction, p hotooxidation in air, anode reactions, shorts and current leakage due to film defects and ion migration in strong fields, and probable sourc es of the slow luminance decay that limits the lifetime of state-of-th e-art devices. (C) 1998 Elsevier Science S.A. All rights reserved.