Research on multi-color OLED with bi-directional charge transfer using Ag: Mg as intermediate electrode

Organic light-emitting devices (OLEDs) have received widespread attention due to their excellent luminescence performance and flexibility. In this work, we demonstrate a novel two-color OLED, in which the forward and reverse units are vertically stacked together using Ag: Mg as an intermediate electrode for charge injection and transfer. Due to the extremely thin Ag: Mg film layer has a relatively smooth surface, it plays a critical role in the reverse unit light emission of the device. Thus, it is realized that the device emits green and red light when forward and reverse voltages are applied respectively. This provides a new possibility for future OLEDs lighting and display developments. The OLEDs were prepared by using such Ag: Mg intermediate electrodes, and a maximum brightness of 451.14 cd/m 2 and an external quantum efficiency ( EQE ) of 3.82% were obtained at a small current density.