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

Introducing a thin Mg layer at the hole injection contact of organic light-emitting devices remarkably improves their operational stability. Devices in which a similar to 2.5 nm 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 600 h of operation at a current density of 62.5 mA/cm(2) with a 50% duty cycle, the luminance of devices containing the Mg layer decreases by only similar to 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. (c) 2006 American Institute of Physics.