We report substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes ͑OLEDs͒. Heat dissipation behavior of top-emission OLEDs fabricated on silicon, glass, and planarized stainless steel substrates was measured by using an infrared camera. Peak temperature measured from the backside of each substrate was saturated to be 21.4, 64.5, and 40.5°C, 180 s after the OLED was operated at luminance of 10 000 cd/ m 2 and 80% luminance lifetime was about 198, 31, and 96 h, respectively. Efficient heat dissipation through the highly thermally conductive substrates reduced temperature increase, resulting in much improved OLED lifetime.

Key technical issues of flexible stainless steel foil substrates are addressed for OLED display backplane applications. Surface roughness and corresponding planarization layer technology development will be the major factors for the stainless steel foil substrates to be used for commercial applications. Promising candidates for the planarization layer materials are reviewed and some of the properties are addressed. In addition, if the substrate is sustained to a constant voltage for guaranteed circuit operation, capacitive coupling through the insulation and planarization dielectric layer, from the conductive substrate to the electrode and circuit elements on it, is also carefully analyzed for panel design and operation. Especially for large size high-resolution display applications, low k and thick planarization layer should be used.

This report describes laboratory tests performed to characterize candidate encapsulation materials with respects to changes in their physical and chemical properties caused by photothermak,aging, Several key material properties relating directly to material degradation and deterioration of performance have been identified and have been monitored as functions of aging conditions and time. This handbook provides a status report on accelerated testing activities and presents experimental data collected before and during December 1982. It will be updated periodically as more data become available.The use of them data in development and dissemination of predictive models describing the rate of aging as a function of stress parameters is a separate and ongoing task. A preliminary version of this model will be published soon in a separate Flat Plate Solar Array Project report. ORI GINAL, PAM IS OF Pooft QUAL",.

Stretchable electrodes with high stretching capability and low sheet resistance were developed using a metal/silver nanowires (AgNWs)/metal hybrid structure on a poly-dimethylsiloxane (PDMS) substrate. A low sheet resistance around 100 mΩ/square was achieved using the hybrid structures of Ag/AgNWs/Ag and Cu/AgNWs/Cu electrodes. The stretching capability under single and multi-cycling strain conditions was greatly improved due the AgNWs in-between top and bottom metal electrodes. The random connection of AgNWs generates new current path over the various cracks and wavy structures of the metal electrodes, which improve the initial resistance, the stretching capability of single strain up to 16 % and the resistance stability of 100 times cycling strain for the electrodes. Using a simple resistor model, it was shown that the hybrid structure is effective to improve the stretching capability of the stretchable metal electrodes due to random connection of AgNWs in-between the metal electrodes.