Integration of high brightness and low operating voltage green organic light-emitting diodes on complementary metal-oxide semiconductor backplane

Abstract

We report high brightness and low operating voltage efficient green organic light-emitting diodes (OLEDs) based on silicon complementary metal-oxide semiconductor (CMOS) backplane which can be used in applications such as microdisplays. The small molecule top-emitting OLEDs are based on a fluorescent green emitter accompanied by blocking, doped charge transport layers, and an anode fabricated with standard CMOS processes of a 200 mm integrated circuit (IC) fab. The devices are designed to maximize the efficiency under low operative bias so as to fit the limited voltage budget of the IC. This was done by making optical simulations of the device structure, optimizing the organic layer thicknesses and charge injection in the n and p transport layers. The devices reach a current efficacy of 21.6 cd/A at a luminance of 20,000 cd/m2. The devices exhibit a voltage swing as low as 2.95 V for a contrast ratio of 1000. The optimized devices have a high lifetime of 6000 and 8800 h at 5000 cd/m2. Furthermore, aging inside the emission layer is investigated.