Improved operational stability of polyfluorene-based organic light-emitting diodes with plasma-treated indium-tin-oxide anodes

Abstract

Double layer green light-emitting diodes were fabricated on indium-tin-oxide (ITO) anodes with a modified poly(3,4-ethylene dioxythiophene) doped with polystyrene sulfonate layer as a hole-injection/transport material, and a poly(9,9-dioctylfluorene) based system as the emitting layer. The effect of anode surface modification by oxygen-plasma and aquaregia cleaning, both alone and in combination, on the operational stability of the device was investigated. Two considerations are indicated for optimum operational stability. Thermal management of the diode provides significant scope for improvements, while the ITO anode and in general, the electrical properties of the hole-injecting contact are crucial to device operation.