Gunther Haas

P‐157: Electrical Modeling and Numerical Simulation of Doped Multilayer Organic Light‐Emitting Diodes (OLEDs)

This work aims at explaining and predicting the influence of dye doping and space charge effects on charge carrier transport at different operating temperatures. for that purpose, current-voltage J-V characteristics for typical electrically-doped multilayer OLEDs have been simulated. The results are in good agreement with experiment.

Stable, highly efficient and temperature resistant organic light-emitting devices

Highly efficient small molecule-based organic light-emitting devices (OLED) that use electrically doped charge injection layers are presented. These structures exhibit low power consumption, long lifetime and high stability when operated at ambient temperature. It is also shown that their performances do not change significantly even when devices are stored at 90 °C for 80 days or 110 °C for 24 h. Such OLED structures thus fulfill the most severe requirements for mobile display applications.

A 5.4 MDOT OLED microdisplay for digital night vision and image fusion

We developed a 0.61 diagonal OLED microdisplay dedicated to electronic viewfinders for digital vision systems, e.g. for security or other professional applications. The microdisplay has a very high resolution of 5.4 million subpixels and combines excellent image quality with low power consumption and a 10bit per color digital input. Subpixel pitch is 4.7x4.7μm². Thanks to the versatile architecture of the underlying ASIC circuit, the device can be easily adapted to different applications and image formats: In the standard full color version, the resulting resolution is 1300 by 1044 pixels (SXGA). In a monochrome version, the resolution is 2600 by 2088 independent pixels, enabling e.g. digital night vision at full 2K by 2K resolution. In addition to this, we developed two- and three color versions of the display that allow to merge high resolution monochrome images e.g.in 2K by 2K resolution with lower resolution images e.g., from an infrared sensor for image fusion or for adding colored graphical overlays.

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

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 opera- tive 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∕m 2 . 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∕m 2 . Further- more, aging inside the emission layer is investigated.

Electrical simulations of doped multilayer organic light-emitting diodes (OLEDs) under temperature stress for high current densities

— This work aims at explaining and predicting the influence of the thickness of organic materials, dye doping, and space-charge effects on charge-carrier transport at different operating temperatures for high current densities (50 ≤ J ≤ 7000 mA/cm2). For the purpose of determining these influences, current-voltage characteristics for typical electrically doped multilayer organic light-emitting diodes (OLEDs) have been simulated. The results of the simulations concur with experimental data.

58.2: Invited Paper: Novel High Efficiency Top Emission OLEDs for Display and Lighting Applications

We present results on low voltage and highly efficient OLED devices. The architecture based on doped transport layers is compatible with established manufacturing equipment, and shows long lifetime, good temperature stability, very low voltage drift, and very low heat dissipation. Main impacts are passive and active matrix displays with very low power consumption, use of a-Si backplanes, and realization of ITO free structures, e.g. for lighting applications.