Stability and characterization of large area polymer light-emitting diodesover extended periods

In order to exploit the extensive potential of polymer light-emitting diode s in commercial applications a number of lifetime specifications have to be met. In this paper we report on the performance and stability of polymer l ight-emitting diodes based on fully conjugated PPV. Lifetime measurements h ave been performed on small (5 mm(2)) and large (8 cm(2)) area devices unde r different conditions, including variations in temperature, luminescence i ntensity and humidity. It will be shown that polymer LEDs can withstand ext reme lifetime tests successfully. The results are compared with lifetime sp ecifications for applications in consumer applications and are discussed in terms of the stability of the emissive polymer. Spectral measurements (IR, FL) as a function of the operational lifetime are presented. (C) 1999 Else vier Science B.V. All rights reserved.