Flexible organic light-emitting diodes with efficiency improvement by dielectric-metal-dielectric anode

Flexible displays and lightings have attracted tremendous attention recently. However, conventional organic light-emitting diodes (OLEDs) with ITO cannot meet market needs due to its poor flexibility. There have been efforts on developing a variety of flexible transparent conductors (FTCs), such as metal mesh, Ag nanowires, conducting oxides, thin metals, two-dimensional materials [1]. While many issues due to stability and reliability were addressed in most of the FTCs, dielectric-metal-dielectric (DMD) films have been considered the most promising FTCs due to its high stability, flexibility, uniformity, and uniform charge injection for future large-area flexible display and lightings [2]. Recently, we developed ITO-based DMDs fabricated by ITO/CuAg/ITO stacks, which are highly flexible, stable, and conductive with good uniformity over a large area [3]. Also, this DMD shows very high transmittance over the entire visible wavelength range, while it suppresses significant amount of UV and infrared light. Therefore, we used this DMD-based FTC into conventional OLEDs, and observed that the ITO-based DMD is not only compatible with high efficiency OLEDs, but also helps to increase efficiency and flexibility of OLEDs.