Lifetime enhanced phosphorescent organic light emitting diode using an electron scavenger layer

We demonstrate a method to improve lifetime of a phosphorescent organic light emitting diode (OLED) using an electron scavenger layer (ESL) in a hole transporting layer (HTL) of the device. We use a bis(1-(phenyl)isoquinoline)iridium(III)acetylacetonate [Ir(piq)(2)(acac)] doped HTL to stimulate radiative decay, preventing thermal degradation in HTL. The ESL effectively prevented non-radiative decay of leakage electron in HTL by converting non-radiative decay to radiative decay via a phosphorescent red emitter, Ir(piq)(2)(acac). The lifetime of device (t(95): time after 5% decrease of luminance) has been increased from 75 h to 120 h by using the ESL in a phosphorescent green-emitting OLED. (C) 2015 AIP Publishing LLC.