Towards organic light-emitting diode microdisplays with sub-pixel patterning

We report on solution processed top-emitting organic light-emitting diodes (TEOLEDs) that are compatible with TFT- and CMOS-substrates, thus being applicable in full-color microdisplays. In this device geometry TEOLEDs offer highly tunable and controllable color-coordinates. Compared to the standard sRGB-colorspace the color gamut is increased by 18%. The CIE (Commission internationale de l’éclairage) color coordinates are more saturated in the red and green spectral region and comparable in the blue region. Brightness levels of 1000 cd/m2 are reached at voltages below 7 V for all colors which is within the operating voltage range of CMOS-backplanes. The polymeric emitters are crosslinkable and can be patterned in a UV-lithography process. The achieved minimum feature size is suitable for high resolution microdisplays.