Defektcharakterisierung von OLED-Systemen auf flexiblen Metallsubstraten

Organic light emitting devices (OLEDs) are becoming increasingly attractive because of the high power efficiency, bending property and high potential of low production costs. Their performance of power efficiency and lifetime has steadily increased during recent years. In contrast to inorganic LEDs, OLED light sources can be built as surface-emitting sources that are colour tunable, potentially cheap, and flexible. A novel approach has been started to establish high efficient small molecule OLED deposition on metal foil in a roll-to-roll vacuum process. Using low cost metal foil as a substrate for the OLED combined with high throughput by a roll-to-roll production will allow a major cost reducing step to penetrate into the general lighting market. For higher yield, power efficiency and lifetime of OLED systems the purity of materials and clean deposition processes are decisive. Especially for enlarged areas the device production via the number of thin film deposition processes requires a low particle and defect density. The thesis presents qualitative and quantitative characterization of surface morphologies, defects and particles on substrates by the use of optical inspection techniques and analyzing methods. An introduction of an optical roll-to-roll defect inspection system will be presented. This novel approach of roll-to-roll inspection allows automatically determination of defect densities divided in different defect types. The determination into different defect types is a powerful method to identify defects which are responsible for high leakage, lower lifetime and shortcut behavior of OLED systems.