Transient Electroluminescence of White Organic Light-Emitting Diodes with Blue Phosphorescent and Red Fluorescent Emissive Layers

Abstract

The transient electroluminescence (EL) of white organic light-emitting diodes (OLEDs) with blue phosphorescent and red fluorescent emissive layers was investigated by applying voltage pulses on the devices. The transient properties of a blue phosphorescence EL signal are strongly affected by the phosphorescence recombination lifetime. As a result, the transient properties of a white OLED were almost identical to those of a phosphorescent emissive layer. Utilizing the differences in transient characteristics between the fluorescent materials and Ir complexes, the emission color has been successfully tuned by varying applied pulse width and frequency.