Won-jong Kim

Effect of transparent film desiccant on the lifetime of top-emitting active matrix organic light emitting diodes

The effects of a transparent film desiccant on the lifetime of top-emitting active matrix organic light emitting diodes (AMOLEDs) were investigated. The transparent film desiccants were prepared by mixing solutions dispersed with calcium oxide powders and ultraviolet-curable resins. As the solid content in the solutions increased from 15to30wt%, the average particle size increased from 107to240nm, whereas the transmittance of the films decreased from 98% to 80% in the visible range. The devices encapsulated with the transparent film desiccants which contained 20wt% CaO exhibited no dark spots and 97% of the initial luminance, even after being stored for over 500h at 70°C and 90% relative humidity. Also, the operational lifetime of these devices was 1850h, ten times longer than that of a device without desiccant. These results confirmed that the transparent film desiccants, which absorbed the moisture that penetrated into the devices, could be applied to the encapsulation of top-emitting AMOLEDs.

59.3: Paving the Way for Novel Top‐Emitting AMOLED Architecture through New Cathode and ETL Materials

A novel top-emitting AMOLED structure with transparent cathode has been successfully developed. Newly designed thermal deposition enabled to avoid damages to organic layers and to realize totally transparent conducting oxide cathode material with low work-function. Besides, new ETL material with excellent electron transporting characteristics has been designed and synthesized for the new top-emitting structure. Owing to the breakthrough in the transparent cathode and ETL materials, we could make a progress in overcoming the drawbacks of current microcavity- structured top-emitting AMOLED architecture.