Ulrich Denker

62.4: Hybrid Polymer‐OLEDs with Doped Small‐molecule Electron Transport Layers for Display Applications

We report on the development of hybrid P-OLEDs for display applications. Hybrid P-OLEDs combine polymeric hole side and emitter layers with small molecule layers as organic electron side. Experimental data for blue hybrid P-OLEDs is presented and compared to standard P-OLEDs with inorganic cathode side.

Application of redox doping in OTFTs

Molecular redox dopants are tested concerning their application to organic thin-film transistors (OTFT). Here we report on the feasibility of solution processing of molecular-doped transport layers, showing high air-stability of solutions and layers. We apply capacitance spectroscopy to investigate the interface of intrinsic and electrically doped layers. We also show that there is virtually no dopant migration in real devices, even when high electric fields up to 300 kV/cm2 are applied for 1000 h. We report on p- and n-type on OTFTs with silver contacts. The application of injection layers based on redox dopants improves the measured field-effect mobility by about 2 orders of magnitude.

36.5: Late‐News Paper: The Light Distribution in OLEDs and Ways to Increase the Light Outcoupling Efficiency

Power efficiency of organic light emitting devices (OLEDs) is in the focus of worldwide research in order to reduce power consumption of displays and to improve the competitive situation of OLEDs for lighting devices. The optical properties of OLEDs are studied with the aim to enhance the fraction of light coupled out of these devices. Simulation software has been used to analyze the transfer of internally generated emission into usable external light modes. Results from modeling have been compared to experimental data to build trust into the validity of the results. Critical parameters influencing outcoupling properties have been identified. Thus, 185lm/W at 1000cd/m2 have been achieved for a green PIN-OLED using a high-n substrate & half ball lens. Finally, some conclusions for the design of outcoupling enhancing means are drawn.