LOW-VOLTAGE OPERATION OF LARGE-AREA POLYMER LEDS

Continuous improvement in the materials, processing and device structu re of light-emitting diodes based on fully conjugated PPV-type polymer s has led to a performance level suitable for application. In this pap er we report on the electrical characteristics of large area devices, and show lifetime data at room temperature of several thousands of hou rs. In order to come to a more convenient testing scheme, lifetimes ha ve been measured at higher operational intensity as well as elevated t emperature and relative humidity. From these data, device degradation at normal operating conditions can be extrapolated. (C) 1997 Elsevier Science S.A.