Operating stability of light-emitting polymer diodes based on poly(p-phenylene vinylene)

We have developed modified poly(p-phenylene vinylene) (PPV) to improve its performance in organic electroluminescent devices. Encapsulated single-layer devices with this PPV on indium–tin oxide and a calcium cathode have been operated in air for >7000 h at 20 °C and >1100 h at 80 °C without noticeable degradation. Devices fabricated with this PPV, a conducting polymer layer as anode, and a sputtered low work-function alloy as cathode have efficiencies of over 2 lm/W, brightnesses of >600 Cd/m2 at 4 V, and lifetimes of >1400 h driven at ∼100 Cd/m2 initial brightness.