Improving the stability of organic light-emitting devices by using a thin Mg anode buffer layer

Abstract

Introducing a thin Mg layer at the hole injection contact of organic light-emitting devices remarkably improves their operational stability. Devices in which a ∼2.5nm thick Mg layer is inserted between the indium tin oxide anode and a tetrafluoro-tetracyanoquinodimethane-doped hole transport material layer exhibit a significantly longer lifetime compared to similar devices without the Mg layer. After 600h of operation at a current density of 62.5mA∕cm2 with a 50% duty cycle, the luminance of devices containing the Mg layer decreases by only ∼10% of the initial value. The stability enhancement resulting from using the Mg layer is attributed to improved balance in charge injection at the anode and cathode contacts.